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Sample records for bed combustion fly

  1. Synthetic aggregate compositions derived from spent bed materials from fluidized bed combustion and fly ash

    DOEpatents

    Boyle, Michael J.

    1994-01-01

    Cementitious compositions useful as lightweight aggregates are formed from a blend of spent bed material from fluidized bed combustion and fly ash. The proportions of the blend are chosen so that ensuing reactions eliminate undesirable constituents. The blend is then mixed with water and formed into a shaped article. The shaped article is preferably either a pellet or a "brick" shape that is later crushed. The shaped articles are cured at ambient temperature while saturated with water. It has been found that if used sufficiently, the resulting aggregate will exhibit minimal dimensional change over time. The aggregate can be certified by also forming standardized test shapes, e.g., cylinders while forming the shaped articles and measuring the properties of the test shapes using standardized techniques including X-ray diffraction.

  2. Distribution of polycyclic aromatic hydrocarbons in fly ash during coal and residual char combustion in a pressurized fluidized bed

    SciTech Connect

    Hongcang Zhou; Baosheng Jin; Rui Xiao; Zhaoping Zhong; Yaji Huang

    2009-04-15

    To investigate the distribution of polycyclic aromatic hydrocarbons (PAHs) in fly ash, the combustion of coal and residual char was performed in a pressurized spouted fluidized bed. After Soxhlet extraction and Kuderna-Danish (K-D) concentration, the contents of 16 PAHs recommended by the United States Environmental Protection Agency (U.S. EPA) in coal, residual char, and fly ash were analyzed by a high-performance liquid chromatography (HPLC) coupled with fluorescence and diode array detection. The experimental results show that the combustion efficiency is lower and the carbon content in fly ash is higher during coal pressurized combustion, compared to the residual char pressurized combustion at the pressure of 0.3 MPa. Under the same pressure, the PAH amounts in fly ash produced from residual char combustion are lower than that in fly ash produced from coal combustion. The total PAHs in fly ash produced from coal and residual char combustion are dominated by three- and four-ring PAHs. The amounts of PAHs in fly ash produced from residual char combustion increase and then decrease with the increase of pressure in a fluidized bed. 21 refs., 1 fig., 4 tabs.

  3. Desulfurization Characteristics of Fly Ash Recirculation and Combustion in the Circulating Fluidized Bed Boiler

    NASA Astrophysics Data System (ADS)

    Li, S. F.; Fang, M. X.; Yu, B.; Wang, Q. H.; Luo, Z. Y.

    The experiments of the fly ash recycle combustion using Guizhou anthracite were carried out in a bench scale circulating fluidized bed (CFB) combustor. Effects of some key operating parameters such as recycle ash to coal mass ratio (Ca to S molar ratio), temperature, reactivation modeof fly ash, circulation rateand fluidization velocity on the desulfurization efficiency were intensively investigated. It is shown that thelimestone utilization efficiency could be improved about 30% with the following operating conditions: the mass ratio of fly ash (reactivated by water and dried at 90°C) to coal was 0.45, the furnace temperature was 880°C, the water to ash mass ratio was 4.5% (the water-to-calcium molar ratio was 0.55) and circulation rate was 18.

  4. Utilization of blended fluidized bed combustion (FBC) ash and pulverized coal combustion (PCC) fly ash in geopolymer.

    PubMed

    Chindaprasirt, Prinya; Rattanasak, Ubolluk

    2010-04-01

    In this paper, synthesis of geopolymer from fluidized bed combustion (FBC) ash and pulverized coal combustion (PCC) fly ash was studied in order to effectively utilize both ashes. FBC-fly ash and bottom ash were inter-ground to three different finenesses. The ashes were mixed with as-received PCC-fly ash in various proportions and used as source material for synthesis of geopolymer. Sodium silicate (Na(2)SiO(3)) and 10M sodium hydroxide (NaOH) solutions at mass ratio of Na(2)SiO(3)/NaOH of 1.5 and curing temperature of 65 degrees C for 48h were used for making geopolymer. X-ray diffraction (XRD), scanning electron microscopy (SEM), degree of reaction, and thermal gravimetric analysis (TGA) were performed on the geopolymer pastes. Compressive strength was also tested on geopolymer mortars. The results show that high strength geopolymer mortars of 35.0-44.0MPa can be produced using mixture of ground FBC ash and as-received PCC-fly ash. Fine FBC ash is more reactive and results in higher degree of reaction and higher strength geopolymer as compared to the use of coarser FBC ash. Grinding increases reactivity of ash by means of increasing surface area and the amount of reactive phase of the ash. In addition, the packing effect due to fine particles also contributed to increase in strength of geopolymers.

  5. Utilization of blended fluidized bed combustion (FBC) ash and pulverized coal combustion (PCC) fly ash in geopolymer

    SciTech Connect

    Chindaprasirt, Prinya; Rattanasak, Ubolluk

    2010-04-15

    In this paper, synthesis of geopolymer from fluidized bed combustion (FBC) ash and pulverized coal combustion (PCC) fly ash was studied in order to effectively utilize both ashes. FBC-fly ash and bottom ash were inter-ground to three different finenesses. The ashes were mixed with as-received PCC-fly ash in various proportions and used as source material for synthesis of geopolymer. Sodium silicate (Na{sub 2}SiO{sub 3}) and 10 M sodium hydroxide (NaOH) solutions at mass ratio of Na{sub 2}SiO{sub 3}/NaOH of 1.5 and curing temperature of 65 deg. C for 48 h were used for making geopolymer. X-ray diffraction (XRD), scanning electron microscopy (SEM), degree of reaction, and thermal gravimetric analysis (TGA) were performed on the geopolymer pastes. Compressive strength was also tested on geopolymer mortars. The results show that high strength geopolymer mortars of 35.0-44.0 MPa can be produced using mixture of ground FBC ash and as-received PCC-fly ash. Fine FBC ash is more reactive and results in higher degree of reaction and higher strength geopolymer as compared to the use of coarser FBC ash. Grinding increases reactivity of ash by means of increasing surface area and the amount of reactive phase of the ash. In addition, the packing effect due to fine particles also contributed to increase in strength of geopolymers.

  6. Fabrication and properties of foam geopolymer using circulating fluidized bed combustion fly ash

    NASA Astrophysics Data System (ADS)

    Liu, Ze; Shao, Ning-ning; Wang, Dong-min; Qin, Jun-feng; Huang, Tian-yong; Song, Wei; Lin, Mu-xi; Yuan, Jin-sha; Wang, Zhen

    2014-01-01

    In recent years, circulating fluidized bed combustion fly ash (CFA) is used as a raw material for geopolymer synthesis. Hydrogen peroxide was employed as a foaming agent to prepare CFA-based foam geopolymer. The particle distribution, mineral composition, and chemical composition of CFA were examined firstly. Geopolymerization products were characterized by mechanical testing, scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF). The CFA-based foam geopolymer was successfully fabricated with different contents of hydrogen peroxide and exhibited uncompleted alkali reaction and reasonable strength with relative low atomic ratios of Si/Al and Si/Na. Type-C CFA in this research could be recycled as an alternative source material for geopolymer production.

  7. Low-reactive circulating fluidized bed combustion (CFBC) fly ashes as source material for geopolymer synthesis.

    PubMed

    Xu, Hui; Li, Qin; Shen, Lifeng; Zhang, Mengqun; Zhai, Jianping

    2010-01-01

    In this contribution, low-reactive circulating fluidized bed combustion (CFBC) fly ashes (CFAs) have firstly been utilized as a source material for geopolymer synthesis. An alkali fusion process was employed to promote the dissolution of Si and Al species from the CFAs, and thus to enhance the reactivity of the ashes. A high-reactive metakaolin (MK) was also used to consume the excess alkali needed for the fusion. Reactivities of the CFAs and MK were examined by a series of dissolution tests in sodium hydroxide solutions. Geopolymer samples were prepared by alkali activation of the source materials using a sodium silicate solution as the activator. The synthesized products were characterized by mechanical testing, scanning electron microscopy (SEM), X-ray diffractography (XRD), as well as Fourier transform infrared spectroscopy (FTIR). The results of this study indicate that, via enhancing the reactivity by alkali fusion and balancing the Na/Al ratio by additional aluminosilicate source, low-reactive CFAs could also be recycled as an alternative source material for geopolymer production.

  8. Low-reactive circulating fluidized bed combustion (CFBC) fly ashes as source material for geopolymer synthesis

    SciTech Connect

    Xu Hui; Li Qin; Shen Lifeng; Zhang Mengqun; Zhai Jianping

    2010-01-15

    In this contribution, low-reactive circulating fluidized bed combustion (CFBC) fly ashes (CFAs) have firstly been utilized as a source material for geopolymer synthesis. An alkali fusion process was employed to promote the dissolution of Si and Al species from the CFAs, and thus to enhance the reactivity of the ashes. A high-reactive metakaolin (MK) was also used to consume the excess alkali needed for the fusion. Reactivities of the CFAs and MK were examined by a series of dissolution tests in sodium hydroxide solutions. Geopolymer samples were prepared by alkali activation of the source materials using a sodium silicate solution as the activator. The synthesized products were characterized by mechanical testing, scanning electron microscopy (SEM), X-ray diffractography (XRD), as well as Fourier transform infrared spectroscopy (FTIR). The results of this study indicate that, via enhancing the reactivity by alkali fusion and balancing the Na/Al ratio by additional aluminosilicate source, low-reactive CFAs could also be recycled as an alternative source material for geopolymer production.

  9. Hybrid fluidized bed combuster

    DOEpatents

    Kantesaria, Prabhudas P.; Matthews, Francis T.

    1982-01-01

    A first atmospheric bubbling fluidized bed furnace is combined with a second turbulent, circulating fluidized bed furnace to produce heat efficiently from crushed solid fuel. The bed of the second furnace receives the smaller sizes of crushed solid fuel, unreacted limestone from the first bed, and elutriated solids extracted from the flu gases of the first bed. The two-stage combustion of crushed solid fuel provides a system with an efficiency greater than available with use of a single furnace of a fluidized bed.

  10. Quantitative evaluation of minerals in fly ashes of biomass, coal and biomass-coal mixture derived from circulating fluidised bed combustion technology.

    PubMed

    Koukouzas, Nikolaos; Ward, Colin R; Papanikolaou, Dimitra; Li, Zhongsheng; Ketikidis, Chrisovalantis

    2009-09-30

    The chemical and mineralogical composition of fly ash samples collected from laboratory scale circulating fluidised bed (CFB) combustion facility have been investigated. Three fly ashes were collected from the second cyclone in a 50 kW laboratory scale boiler, after the combustion of different solid fuels. Characterisation of the fly ash samples was conducted by means of X-ray fluorescence (XRF), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Quantitative analysis of the crystalline (mineral) and amorphous phases in each ash sample was carried out using the Rietveld-based Siroquant system, with an added spike of ZnO to evaluate the amorphous content. SiO(2) is the dominant oxide in the fly ashes, with CaO, Al(2)O(3) and Fe(2)O(3) also present in significant proportions. XRD results show that all three fly ashes contain quartz, anhydrite, hematite, illite and amorphous phases. The minerals calcite, feldspar, lime and periclase are present in ashes derived from Polish coal and/or woodchips. Ash from FBC combustion of a Greek lignite contains abundant illite, whereas illite is present only in minor proportions in the other ash samples.

  11. Combustion in fluidized beds

    SciTech Connect

    Dry, F.J.; La Nauze, R.D. )

    1990-07-01

    Circulating fluidized-bed (CFB) combustion systems have become popular since the late 1970s, and, given the current level of activity in the area,it is clear that this technology has a stable future in the boiler market. For standard coal combustion applications, competition is fierce with mature pulverized-fuel-based (PF) technology set to maintain a strong profile. CFB systems, however, can be more cost effective than PF systems when emission control is considered, and, as CFB technology matures, it is expected that an ever-increasing proportion of boiler installations will utilize the CFB concept. CFB systems have advantages in the combustion of low-grade fuels such as coal waste and biomass. In competition with conventional bubbling beds, the CFB boiler often demonstrates superior carbon burn-out efficiency. The key to this combustion technique is the hydrodynamic behavior of the fluidized bed. This article begins with a description of the fundamental fluid dynamic behavior of the CFB system. This is followed by an examination of the combustion process in such an environment and a discussion of the current status of the major CFB technologies.

  12. Fluidized-bed combustion

    SciTech Connect

    Botros, P E

    1990-04-01

    This report describes the activities of the Morgantown Energy Technology Center's research and development program in fluidized-bed combustion from October 1, 1987, to September 30, 1989. The Department of Energy program involves atmospheric and pressurized systems. Demonstrations of industrial-scale atmospheric systems are being completed, and smaller boilers are being explored. These systems include vortex, multi-solid, spouted, dual-sided, air-cooled, pulsed, and waste-fired fluidized-beds. Combustion of low-rank coal, components, and erosion are being studied. In pressurized combustion, first-generation, combined-cycle power plants are being tested, and second-generation, advanced-cycle systems are being designed and cost evaluated. Research in coal devolatilization, metal wastage, tube corrosion, and fluidization also supports this area. 52 refs., 24 figs., 3 tabs.

  13. Alkali activation of recovered fuel-biofuel fly ash from fluidised-bed combustion: Stabilisation/solidification of heavy metals.

    PubMed

    Yliniemi, Juho; Pesonen, Janne; Tiainen, Minna; Illikainen, Mirja

    2015-09-01

    Recovered fuel-biofuel fly ash from a fluidized bed boiler was alkali-activated and granulated with a sodium-silicate solution in order to immobilise the heavy metals it contains. The effect of blast-furnace slag and metakaolin as co-binders were studied. Leaching standard EN 12457-3 was applied to evaluate the immobilisation potential. The results showed that Ba, Pb and Zn were effectively immobilised. However, there was increased leaching after alkali activation for As, Cu, Mo, Sb and V. The co-binders had minimal or even negative effect on the immobilisation. One exception was found for Cr, in which the slag decreased leaching, and one was found for Cu, in which the slag increased leaching. A sequential leaching procedure was utilized to gain a deeper understanding of the immobilisation mechanism. By using a sequential leaching procedure it is possible fractionate elements into watersoluble, acid-soluble, easily-reduced and oxidisable fractions, yielding a total 'bioavailable' amount that is potentially hazardous for the environment. It was found that the total bioavailable amount was lower following alkali activation for all heavy metals, although the water-soluble fraction was higher for some metals. Evidence from leaching tests suggests the immobilisation mechanism was chemical retention, or trapping inside the alkali activation reaction products, rather than physical retention, adsorption or precipitation as hydroxides.

  14. Bed material agglomeration during fluidized bed combustion

    SciTech Connect

    Brown, R.C.; Dawson, M.R.; Noble, S.

    1993-02-01

    The purpose of this project is to determine the physical and chemical reactions which led to the undesired agglomeration of bed material during fluidized bed combustion and to relate these reactions to specific causes. Survey of industrial-scale fluidized bed combustors is being conducted to determine the occurrence of bed agglomeration and the circumstances under which agglomeration took place. This task should be finished by the end of February. Samples of bed material, agglomerate material, and boiler deposits are being requested from boiler operators as part of the survey. Once received, these sample will be analyzed to determine chemical and mineralogic composition. The bulk chemical determination will be performed using x-ray fluorescence and inductively coupled plasma-optical emission (ICP). Mineralogy will be detected by x-ray diffraction (XRD). Chemical and mineral reactions will be determined by scanning electron microscopy, optical microscopy, and electron microprobe.

  15. Reversed flow fluidized-bed combustion apparatus

    DOEpatents

    Shang, Jer-Yu; Mei, Joseph S.; Wilson, John S.

    1984-01-01

    The present invention is directed to a fluidized-bed combustion apparatus provided with a U-shaped combustion zone. A cyclone is disposed in the combustion zone for recycling solid particulate material. The combustion zone configuration and the recycling feature provide relatively long residence times and low freeboard heights to maximize combustion of combustible material, reduce nitrogen oxides, and enhance sulfur oxide reduction.

  16. Pulsed atmospheric fluidized bed combustion

    SciTech Connect

    Not Available

    1992-10-01

    The design of the Pulsed Atmospheric Fluidized Bed Combustor (PAFBC) as described in the Quarterly Report for the period April--June, 1992 was reviewed and minor modifications were included. The most important change made was in the coal/limestone preparation and feed system. Instead of procuring pre-sized coal for testing of the PAFBC, it was decided that the installation of a milling system would permit greater flexibility in the testing with respect to size distributions and combustion characteristics in the pulse combustor and the fluid bed. Particle size separation for pulse combustor and fluid bed will be performed by an air classifier. The modified process flow diagram for the coal/limestone handling system is presented in Figure 1. The modified process flow diagrams of the fluidized bed/steam cycle and ash handling systems are presented in Figures 2 and 3, respectively.

  17. Pulsed atmospheric fluidized bed combustion

    SciTech Connect

    Not Available

    1992-05-01

    During this first quarter, a lab-scale water-cooled pulse combustor was designed, fabricated, and integrated with old pilot-scale PAFBC test systems. Characterization tests on this pulse combustor firing different kinds of fuel -- natural gas, pulverized coal and fine coal -- were conducted (without fluidized bed operation) for the purpose of finalizing PAFBC full-scale design. Steady-state tests were performed. Heat transfer performance and combustion efficiency of a coal-fired pulse combustor were evaluated.

  18. Fluidized bed coal combustion reactor

    NASA Technical Reports Server (NTRS)

    Moynihan, P. I.; Young, D. L. (Inventor)

    1981-01-01

    A fluidized bed coal reactor includes a combination nozzle-injector ash-removal unit formed by a grid of closely spaced open channels, each containing a worm screw conveyor, which function as continuous ash removal troughs. A pressurized air-coal mixture is introduced below the unit and is injected through the elongated nozzles formed by the spaces between the channels. The ash build-up in the troughs protects the worm screw conveyors as does the cooling action of the injected mixture. The ash layer and the pressure from the injectors support a fluidized flame combustion zone above the grid which heats water in boiler tubes disposed within and/or above the combustion zone and/or within the walls of the reactor.

  19. Pulsed atmospheric fluidized bed combustion

    SciTech Connect

    Not Available

    1989-11-01

    In order to verify the technical feasibility of the MTCI Pulsed Atmospheric Fluidized Bed Combustor technology, a laboratory-scale system was designed, built and tested. Important aspects of the operational and performance parameters of the system were established experimentally. A considerable amount of the effort was invested in the initial task of constructing an AFBC that would represent a reasonable baseline against which the performance of the PAFBC could be compared. A summary comparison of the performance and emissions data from the MTCI 2 ft {times} 2 ft facility (AFBC and PAFBC modes) with those from conventional BFBC (taller freeboard and recycle operation) and circulating fluidized bed combustion (CFBC) units is given in Table ES-1. The comparison is for typical high-volatile bituminous coals and sorbents of average reactivity. The values indicated for BFBC and CFBC were based on published information. The AFBC unit that was designed to act as a baseline for the comparison was indeed representative of the larger units even at the smaller scale for which it was designed. The PAFBC mode exhibited superior performance in relation to the AFBC mode. The higher combustion efficiency translates into reduced coal consumption and lower system operating cost; the improvement in sulfur capture implies less sorbent requirement and waste generation and in turn lower operating cost; lower NO{sub x} and CO emissions mean ease of site permitting; and greater steam-generation rate translates into less heat exchange surface area and reduced capital cost. Also, the PAFBC performance generally surpasses those of conventional BFBC, is comparable to CFBC in combustion and NO{sub x} emissions, and is better than CFBC in sulfur capture and CO emissions even at the scaled-down size used for the experimental feasibility tests.

  20. Pressurized fluidized-bed combustion

    SciTech Connect

    Not Available

    1980-10-01

    The US DOE pressurized fluidized bed combustion (PFBC) research and development program is designed to develop the technology and data base required for the successful commercialization of the PFBC concept. A cooperative program with the US, West Germany, and the UK has resulted in the construction of the 25 MWe IEA-Grimethorpe combined-cycle pilot plant in England which will be tested in 1981. A 13 MWe coal-fired gas turbine (air cycle) at Curtis-Wright has been designed and construction scheduled. Start-up is planned to begin in early 1983. A 75 MWe pilot plant is planned for completion in 1986. Each of these PFBC combined-cycle programs is discussed. The current status of PFB technology may be summarized as follows: turbine erosion tolerance/hot gas cleanup issues have emerged as the barrier technology issues; promising turbine corrosion-resistant materials have been identified, but long-term exposure data is lacking; first-generation PFB combustor technology development is maturing at the PDU level; however, scale-up to larger size has not been demonstrated; and in-bed heat exchanger materials have been identified, but long-term exposure data is lacking. The DOE-PFB development plan is directed at the resolution of these key technical issues. (LCL)

  1. Regeneration of lime from sulfates for fluidized-bed combustion

    DOEpatents

    Yang, Ralph T.; Steinberg, Meyer

    1980-01-01

    In a fluidized-bed combustor the evolving sulfur oxides are reacted with CaO to form calcium sulfate which is then decomposed in the presence of carbonaceous material, such as the fly ash recovered from the combustion, at temperatures of about 900.degree. to 1000.degree. C., to regenerate lime. The regenerated lime is then recycled to the fluidized bed combustor to further react with the evolving sulfur oxides. The lime regenerated in this manner is quite effective in removing the sulfur oxides.

  2. Characterizing fuels for atmospheric fluidized bed combustion

    SciTech Connect

    Marban, G.; Pis, J.J.; Fuertes, A.B.

    1995-10-01

    A complete methodology for characterizing coal combustion in atmospheric fluidized bed reactors is presented. The methodology comprises studies of fragmentation and particle size variations during combustion, necessary to allow an accurate determination of kinetic parameters and attrition rates. Samples of three different carbonaceous materials (a medium-ash lignite, a medium-ash anthracite and a graphite) were pyrolyzed in N{sub 2} and partially burned in air in a bench-scale fluidized bed reactor at different operating conditions. The particle size distribution, apparent density and number of particles were evaluated by Image Analysis. Additionally, the sphericity factors were calculated. Combustion studies were carried out in batch experiments in the laboratory-scale, fluidized bed reactor at the same operating conditions. The reactor outlet concentrations of O{sub 2}, CO{sub 2}, and CO were monitored continuously. The results indicate that only anthracite particles experienced both primary (due to devolatilization) and secondary (during char combustion) fragmentation. Graphite particles underwent secondary fragmentation, whereas lignite particles did not significantly vary in number during combustion. Size and density variations during combustion suggest that graphite particles burn under regime II, interparticle diffusion being the rate controlling step. On the other hand, anthracite and lignite particles developed an ash layer, which may control combustion. The attrition constants of the medium-ash materials (lignite and anthracite) were found to be very low whereas that of graphite was much higher due mainly to peripheral percolation during combustion.

  3. Pyrolysis reactor and fluidized bed combustion chamber

    DOEpatents

    Green, Norman W.

    1981-01-06

    A solid carbonaceous material is pyrolyzed in a descending flow pyrolysis reactor in the presence of a particulate source of heat to yield a particulate carbon containing solid residue. The particulate source of heat is obtained by educting with a gaseous source of oxygen the particulate carbon containing solid residue from a fluidized bed into a first combustion zone coupled to a second combustion zone. A source of oxygen is introduced into the second combustion zone to oxidize carbon monoxide formed in the first combustion zone to heat the solid residue to the temperature of the particulate source of heat.

  4. Loop-bed combustion apparatus

    DOEpatents

    Shang, Jer-Yu; Mei, Joseph S.; Slagle, Frank D.; Notestein, John E.

    1984-01-01

    The present invention is directed to a combustion apparatus in the configuration of a oblong annulus defining a closed loop. Particulate coal together with a sulfur sorbent such as sulfur or dolomite is introduced into the closed loop, ignited, and propelled at a high rate of speed around the loop. Flue gas is withdrawn from a location in the closed loop in close proximity to an area in the loop where centrifugal force imposed upon the larger particulate material maintains these particulates at a location spaced from the flue gas outlet. Only flue gas and smaller particulates resulting from the combustion and innerparticle grinding are discharged from the combustor. This structural arrangement provides increased combustion efficiency due to the essentially complete combustion of the coal particulates as well as increased sulfur absorption due to the innerparticle grinding of the sorbent which provides greater particle surface area.

  5. Co-combustion of tannery sludge in a commercial circulating fluidized bed boiler.

    PubMed

    Dong, Hao; Jiang, Xuguang; Lv, Guojun; Chi, Yong; Yan, Jianhua

    2015-12-01

    Co-combusting hazardous wastes in existing fluidized bed combustors is an alternative to hazardous waste treatment facilities, in shortage in China. Tannery sludge is a kind of hazardous waste, considered fit for co-combusting with coal in fluidized bedboilers. In this work, co-combustion tests of tannery sludge and bituminous coal were conducted in a power plant in Jiaxing, Zhejiang province. Before that, the combustion behavior of tannery sludge and bituminous were studied by thermogravimetric analysis. Tannery sludge presented higher reactivity than bituminous coal. During the co-combustion tests, the emissions of harmful gases were monitored. The results showed that the pollutant emissions met the Chinese standard except for NOx. The Concentrations of seven trace elements (As, Cr, Cd, Ni, Cu, Pb, Mn) in three exit ash flows (bottom ash in bed, fly ash in filter, and submicrometer aerosol in flue gas) were analyzed. The results of mono-combustion of bituminous coal were compared with those of co-combustion with tannery sludge. It was found that chromium enriched in fly ash. At last, the leachability of fly ash and bottom ash was analyzed. The results showed that most species were almost equal to or below the limits except for As in bottom ashes and Cr in the fly ash of co-combustion test. The concentrations of Cr in leachates of co-combustion ashes are markedly higher than that of coal mono-combustion ashes.

  6. Metallic species derived from fluidized bed coal combustion. [59 references

    SciTech Connect

    Natusch, D.F.S.; Taylor, D.R.

    1980-01-01

    Samples of fly ash generated by the combustion of Montana Rosebud coal in an experimental 18 inch fluidized bed combustor were collected. The use of a heated cascade impactor permitted collection of size fractionated material that avoided condensation of volatile gases on the particles. Elemental concentration trends were determined as a function of size and temperature and the results compared to published reports for conventional power plants. The behavior of trace metals appears to be substantially different in the two systems due to lower operating temperatures and the addition of limestone to the fluidized bed. Corrosion of the impactor plates was observed at the highest temperature and lowest limestone feed rate sampled during the study. Data from the elemental concentration and leaching studies suggest that corrosion is most likely due to reactions involving sodium sulfate. However, it is concluded that corrosion is less of a potential problem in fluidized-bed systems than in conventional coal-fired systems.

  7. Fluidized-bed combustion reduces atmospheric pollutants

    NASA Technical Reports Server (NTRS)

    Jonke, A. A.

    1972-01-01

    Method of reducing sulfur and nitrogen oxides released during combustion of fossil fuels is described. Fuel is burned in fluidized bed of solids with simultaneous feeding of crushed or pulverized limestone to control emission. Process also offers high heat transfer rates and efficient contacting for gas-solid reactions.

  8. Internal Combustion Engines as Fluidized Bed Reactors

    NASA Astrophysics Data System (ADS)

    Lavich, Zoe; Taie, Zachary; Menon, Shyam; Beckwith, Walter; Daly, Shane; Halliday, Devin; Hagen, Christopher

    2016-11-01

    Using an internal combustion engine as a chemical reactor could provide high throughput, high chemical conversion efficiency, and reactant/product handling benefits. For processes requiring a solid catalyst, the ability to develop a fluidized bed within the engine cylinder would allow efficient processing of large volumes of fluid. This work examines the fluidization behavior of particles in a cylinder of an internal combustion engine at various engine speeds. For 40 micron silica gel particles in a modified Megatech Mark III transparent combustion engine, calculations indicate that a maximum engine speed of about 60.8 RPM would result in fluidization. At higher speeds, the fluidization behavior is expected to deteriorate. Experiments gave qualitative confirmation of the analytical predictions, as a speed of 48 RPM resulted in fluidized behavior, while a speed of 171 RPM did not. The investigation shows that under certain conditions a fluidized bed can be obtained within an engine cylinder. Corresponding Author.

  9. Pulsed atmospheric fluidized bed combustion. Final report

    SciTech Connect

    1998-03-01

    ThermoChem, under contract to the Department of Energy, conducted extensive research, development and demonstration work on a Pulsed Atmospheric Fluidized Bed Combustor (PAFBC) to confirm that advanced technology can meet these performance objectives. The ThermoChem/MTCI PAFBC system integrates a pulse combustor with an atmospheric bubbling-bed type fluidized bed combustor (BFBC) In this modular configuration, the pulse combustor burns the fuel fines (typically less than 30 sieve or 600 microns) and the fluidized bed combusts the coarse fuel particles. Since the ThermoChem/MTCI PAFBC employs both the pulse combustor and the AFBC technologies, it can handle the full-size range of coarse and fines. The oscillating flow field in the pulse combustor provides for high interphase and intraparticle mass transfer rates. Therefore, the fuel fines essentially burn under kinetic control. Due to the reasonably high temperature (>1093 C but less than the temperature for ash fusion to prevent slagging), combustion of fuel fines is substantially complete at the exit of the pulse combustor. The additional residence time of 1 to 2 seconds in the freeboard of the PAFBC unit then ensures high carbon conversion and, in turn, high combustion efficiency. A laboratory unit was successfully designed, constructed and tested for over 600 hours to confirm that the PAFBC technology could meet the performance objectives. Subsequently, a 50,000 lb/hr PAFBC demonstration steam boiler was designed, constructed and tested at Clemson University in Clemson, South Carolina. This Final Report presents the detailed results of this extensive and successful PAFBC research, development and demonstration project.

  10. Atmospheric fluidized bed combustion gas erosion solution

    SciTech Connect

    Seitzinger, D.L.

    1995-12-31

    The Westwood Generating Station is a 30 MW, anthracite culm-fired plant located near Joliet, Pennsylvania. The culm firing technology is based on the Combustion Engineering-Lurgi circulating fluidized bed combustion (CFBC) technology first introduced in this country in boiler applications in the mid-80`s. This unit went into commercial operation In July 1988 and is the second of its type in service in this country. It is located on the original site of the Westwood Colliery that was in operation from 1920 to 1950 preparing anthracite coal for the commercial market and leaving behind a 15 year fuel supply of anthracite culm, a coal screening waste, that is now the fuel for this station. This paper documents the investigations and corrective actions taken to stop severe tube erosion encountered in the combustor and heat recovery surfaces of the unit. This erosion is attributed to high gas velocities due to changing operation requirements and gas flow distribution.

  11. Second-generation pressurized fluidized bed combustion

    SciTech Connect

    Wolowodiuk, W.; Robertson, A.

    1992-01-01

    Under the sponsorship of the United States Department of Energy, Foster Wheeler Corporation is developing second-generation pressurized fluidized bed combustion (PFBC) power plant technology that will enable this type of plant to operate with net plant efficiencies in the range of 43 to 46 percent (based on the higher heating value of the coal), with a reduction in the cost of electricity of at least 20 percent. A three-phase program is under way. Its scope encompasses the conceptual design of a commercial plant through the process of gathering needed experimental test data to obtain design parameters.

  12. Second-generation pressurized fluidized bed combustion

    SciTech Connect

    Wolowodiuk, W.; Robertson, A.

    1992-05-01

    Under the sponsorship of the United States Department of Energy, Foster Wheeler Corporation is developing second-generation pressurized fluidized bed combustion (PFBC) power plant technology that will enable this type of plant to operate with net plant efficiencies in the range of 43 to 46 percent (based on the higher heating value of the coal), with a reduction in the cost of electricity of at least 20 percent. A three-phase program is under way. Its scope encompasses the conceptual design of a commercial plant through the process of gathering needed experimental test data to obtain design parameters.

  13. Bed material agglomeration during fluidized bed combustion. Final report

    SciTech Connect

    Brown, R.C.; Dawson, M.R.; Smeenk, J.L.

    1996-01-01

    The purpose of this project is to determine the physical and chemical reactions which lead to the undesired agglomeration of bed material during fluidized bed combustion of coal and to relate these reactions to specific causes. A survey of agglomeration and deposit formation in industrial fluidized bed combustors (FBCs) indicate that at least five boilers were experiencing some form of bed material agglomeration. Deposit formation was reported at nine sites with deposits most commonly at coal feed locations and in cyclones. Other deposit locations included side walls and return loops. Three general types of mineralogic reactions were observed to occur in the agglomerates and deposits. Although alkalies may play a role with some {open_quotes}high alkali{close_quotes} lignites, we found agglomeration was initiated due to fluxing reactions between iron (II) from pyrites and aluminosilicates from clays. This is indicated by the high amounts of iron, silica, and alumina in the agglomerates and the mineralogy of the agglomerates. Agglomeration likely originated in the dense phase of the FBC bed within the volatile plume which forms when coal is introduced to the boiler. Secondary mineral reactions appear to occur after the agglomerates have formed and tend to strengthen the agglomerates. When calcium is present in high amounts, most of the minerals in the resulting deposits are in the melilite group (gehlenite, melilite, and akermanite) and pyroxene group (diopside and augite). During these solid-phase reactions, the temperature of formation of the melilite minerals can be lowered by a reduction of the partial pressure of CO{sub 2} (Diopside + Calcite {r_arrow}Akermanite).

  14. Pulsed atmospheric fluidized bed combustion. Final report

    SciTech Connect

    Not Available

    1989-11-01

    In order to verify the technical feasibility of the MTCI Pulsed Atmospheric Fluidized Bed Combustor technology, a laboratory-scale system was designed, built and tested. Important aspects of the operational and performance parameters of the system were established experimentally. A considerable amount of the effort was invested in the initial task of constructing an AFBC that would represent a reasonable baseline against which the performance of the PAFBC could be compared. A summary comparison of the performance and emissions data from the MTCI 2 ft {times} 2 ft facility (AFBC and PAFBC modes) with those from conventional BFBC (taller freeboard and recycle operation) and circulating fluidized bed combustion (CFBC) units is given in Table ES-1. The comparison is for typical high-volatile bituminous coals and sorbents of average reactivity. The values indicated for BFBC and CFBC were based on published information. The AFBC unit that was designed to act as a baseline for the comparison was indeed representative of the larger units even at the smaller scale for which it was designed. The PAFBC mode exhibited superior performance in relation to the AFBC mode. The higher combustion efficiency translates into reduced coal consumption and lower system operating cost; the improvement in sulfur capture implies less sorbent requirement and waste generation and in turn lower operating cost; lower NO{sub x} and CO emissions mean ease of site permitting; and greater steam-generation rate translates into less heat exchange surface area and reduced capital cost. Also, the PAFBC performance generally surpasses those of conventional BFBC, is comparable to CFBC in combustion and NO{sub x} emissions, and is better than CFBC in sulfur capture and CO emissions even at the scaled-down size used for the experimental feasibility tests.

  15. Acidification of calf bedding reduces fly development and bacterial abundance.

    PubMed

    Calvo, M S; Gerry, A C; McGarvey, J A; Armitage, T L; Mitloehner, F M

    2010-03-01

    Environmental stressors, such as high fly density, can affect calf well-being. Sodium bisulfate (SBS) is an acidifier that reduces the pH of flooring and bedding, creating a medium that neither bacteria nor immature flies (also known as larvae or maggots) can thrive in. Two experiments were conducted to investigate the application of SBS to a mixture of rice hull calf bedding and calf slurry (BED) to reduce house fly (Musca domestica L.) larval density and the abundance of bacteria. In experiment 1, dish pans containing 1L of BED and 3,000 house fly eggs were treated with SBS at concentrations of 0, 8.9, 17.7, and 26.5g of SBS/0.05m(2) of BED (CON, LOW, MED, and HIGH, respectively), with each SBS concentration applied to 4 individual pans (16 pans total). Reapplication of the same SBS concentrations in each pan occurred 3 times/wk throughout the 23-d trial. Larval house fly survival was significantly reduced in all pans with SBS relative to CON pans, with lowest survival rates in the MED and HIGH pans (99% and 100% reduction, respectively). The mean pH for each treatment was inversely related to the SBS concentration. In experiment 2, pans containing 1L of BED and 3,000 house fly eggs were treated with either 0g of SBS (CON), 8.9g of SBS/0.05m(2) of BED with reapplication of the acidifier 3 times/wk (SB3x), or 8.9g of SBS/0.05m(2) of BED applied only once at 48h before the end of the 8 d-trial (SB48). Larval house fly survival and bacterial concentrations were reduced (90% larval reduction and 68% bacterial reduction) in the SB3x treatment relative to the CON. Mean pH was also reduced in SB3x pans relative to CON or SB48 pans. Overall, acidification of calf BED using the acidifier SBS resulted in a reduction of bacteria and house fly larval survival. This form of fly control might be expected to reduce adult fly production and, therefore, fly-related stress in calves.

  16. CIRCULATING MOVING BED COMBUSTION PROOF OF CONCEPT

    SciTech Connect

    Jukkola, Glen

    2010-06-30

    Circulating Moving Bed (CMB) combustion technology has its roots in traditional circulating fluidized bed technology and involves a novel method of solid fuel combustion and heat transfer. CMB technology represents a step change in improved performance and cost relative to conventional PC and FBC boilers. The CMB heat exchanger preheats the energy cycle working fluid, steam or air, to the high temperature levels required in systems for advanced power generation. Unique features of the CMB are the reduction of the heat transfer surfaces by about 60% as a result of the enhanced heat transfer rates, flexibility of operation, and about 30% lower cost over existing technology. The CMB Phase I project ran from July 2001 through March 2003. Its objective was to continue development of the CMB technology with a series of proof of concept tests. The tests were conducted at a scale that provided design data for scale up to a demonstration plant. These objectives were met by conducting a series of experiments in ALSTOM Power’s Multi-use Test Facility (MTF). The MTF was modified to operate under CMB conditions of commercial interest. The objective of the tests were to evaluate gas-to-solids heat transfer in the upper furnace, assess agglomeration in the high temperature CMB bubbling bed, and evaluate solids-to-tube heat transfer in the moving bed heat exchanger. The Phase I program results showed that there are still some significant technical uncertainties that needed to be resolved before the technology can be confidently scaled up for a successful demonstration plant design. Work remained in three primary areas: • scale up of gas to solid heat transfer • high temperature finned surface design • the overall requirements of mechanical and process design. The CMB Phase II workscope built upon the results of Phase I and specifically addressed the remaining technical uncertainties. It included a scaled MTF heat transfer test to provide the necessary data to scale up gas

  17. (Pulsed atmospheric fluidized bed combustion (PAFBC))

    SciTech Connect

    Not Available

    1988-10-01

    This first Quarterly Technical Progress Report presents the results of work accomplished during the period April 19 through July 24,1988. The overall objective of the program is the development of a pulsed atmospheric fluidized-bed combustion (PAFBC) technology to burn coal and to provide heat and steam to commercial, institutional, and small industrial applications at a reasonable price in an environmentally acceptable manner. the program scope consisted of two tasks; the first was to establish preliminary feasibility by the use of theoretical and state-of-the-art information. This task was completed during the first quarter of the contract period and a topical report entitled, Pulsed Atmospheric Fluidized Bed combustion (PAFBC) - Preliminary Feasibility Study'' was prepared as a decision point to proceed'' deliverable in accordance with the terms of the contract. This first quarterly progress report therefore covers the contract activities subsequent to the approval of the feasibility study and the decision to proceed with the Task 2 effort. As the initial quarterly technical progress report, this document includes a subsection on background which will be omitted in subsequent reports. All effort during this period was devoted to the design and analysis of the PAFBC. Design drawings were prepared and fabrication and procurement initiated. Quotations were evaluated and a fabrication contract awarded. A site adjacent to the MTCI building was chosen for the installation of the PAFBC. Some ancillary components were purchased, renovated, and tested. Some delays in delivery of components have resulted in some schedule delay. It is anticipated that the program pace will accelerate as soon as parts are received and installation and assembly are initiated. 10 figs.,1 tab.

  18. MERCURY CAPTURE ON COAL COMBUSTION FLY ASH. (R827649)

    EPA Science Inventory

    A study was performed at the Energy and Environmental Research Center (EERC) to test the hypotheses that (1) different carbon types contained in coal combustion fly ash have variable sorption capabilities relative to mercury and (2) the inorganic fraction of coal combustion fl...

  19. Fluidized-bed calciner with combustion nozzle and shroud

    DOEpatents

    Wielang, Joseph A.; Palmer, William B.; Kerr, William B.

    1977-01-01

    A nozzle employed as a burner within a fluidized bed is coaxially enclosed within a tubular shroud that extends beyond the nozzle length into the fluidized bed. The open-ended shroud portion beyond the nozzle end provides an antechamber for mixture and combustion of atomized fuel with an oxygen-containing gas. The arrangement provides improved combustion efficiency and excludes bed particles from the high-velocity, high-temperature portions of the flame to reduce particle attrition.

  20. The study of partitioning of heavy metals during fluidized bed combustion of sewage sludge and coal

    SciTech Connect

    Gulyurtlu, I.; Lopes, M.H.; Abelha, P.; Cabrita, I.; Oliveira, J.F.S.

    2006-06-15

    The behavior of Cd, Cr, Cu, Co, Mn, Ni, Pb, Zn, and Hg during the combustion tests of a dry granular sewage sludge on a fluidized bed combustor pilot (FBC) of about 0.3 MW was evaluated. The emissions of these heavy metals from mono-combustion were compared with those of co-combustion of the sludge with a bituminous coal. The effect of the addition of limestone was also studied in order to retain sulphur compounds and to verify its influence on the retention of heavy metals (HM). Heavy metals were collected and analyzed from different locations of the installation, which included the stack, the two cyclones, and the material removed from the bed. The results showed that the volatility of metals was rather low, resulting in emissions below the legal limits of the new directive on incineration, with the exception of Hg during the mono-combustion tests. The partitioning of metals, except for Hg, appeared to follow that of ashes, amounting to levels above 90% in the bed streams in the mono-combustion case. For co-combustion, there was a lower fixation of HM in the bed ashes, mostly originating essentially from the sewage sludge, ranging between 40% and 80%. It is believed that in this latter case, a slightly higher temperature could have enhanced the volatilization, especially of Cd and Pb. However these metals were then retained in fly ashes captured in the cyclones. In the case of Hg, the volatilisation was complete. The bed ashes were free of Hg and part of Hg was retained in the cyclones and the rest was emitted either with fine ash particles or in gaseous forms. In mono-combustion the Hg emissions from the stack (particles and gas) accounted, for about 50%. This appeared to have significantly decreased in the case of co-combustion, as only about 75% has been emitted, due to the retention effect of cyclone ashes.

  1. Steam generator with circulating atmospheric fluidized bed combustion

    NASA Astrophysics Data System (ADS)

    Wein, W.; Hoeffgen, H.; Maintok, K. H.; Daradimos, G.

    1982-08-01

    The combustion of coal in power plants by conventional combustion techniques is studied with emphasis on combustion in a circulating atmospheric fluidized bed (CFBC). The CFBC method stays half way between the classical fluidized bed with a well defined bed height and the pneumatic transport where particles and fluidizing gas have the same velocity. The main advantages of CFBC are: flexibility with respect to coal types; easy elimination of 80% of sulfur by mixing the coal with calcium carbonate to a molecular ratio Ca/S of about two; reduced nitrogen oxides production due to the low combustion temperature of 900 C; high steam production efficiency with the combustion degree exceeding 99%; high overall efficiency with no further desulfurizing being needed; easy regulation; high heat transmission rates (350 to 400 W/m2K) reducing exchange surfaces; small boiler building; and the possibility to build in one module a 300 MW unit.

  2. Staged fluidized-bed combustion and filter system

    DOEpatents

    Mei, Joseph S.; Halow, John S.

    1994-01-01

    A staged fluidized-bed combustion and filter system for substantially reducing the quantity of waste through the complete combustion into ash-type solids and gaseous products. The device has two fluidized-bed portions, the first primarily as a combustor/pyrolyzer bed, and the second as a combustor/filter bed. The two portions each have internal baffles to define stages so that material moving therein as fluidized beds travel in an extended route through those stages. Fluidization and movement is achieved by the introduction of gases into each stage through a directional nozzle. Gases produced in the combustor/pyrolyzer bed are permitted to travel into corresponding stages of the combustor/filter bed through screen filters that permit gas flow but inhibit solids flow. Any catalyst used in the combustor/filter bed is recycled. The two beds share a common wall to minimize total volume of the system. A slightly modified embodiment can be used for hot gas desulfurization and sorbent regeneration. Either side-by-side rectangular beds or concentric beds can be used. The system is particularly suited to the processing of radioactive and chemically hazardous waste.

  3. Fundamental Study of Low NOx Combustion Fly Ash Utilization

    SciTech Connect

    E. M. Suubert; I. Kuloats; K. Smith; N. Sabanegh; R.H. Hurt; W. D. Lilly; Y. M. Gao

    1997-05-01

    This study is principally concerned with characterizing the organic part of coal combustion fly ashes. High carbon fly ashes are becoming more common as by-products of low-NOx combustion technology, and there is need to learn more about this fraction of the fly ash. The project team consists of two universities, Brown and Princeton, and an electrical utility, New England Power. A sample suite of over forty fly ashes has been gathered from utilities across the United States, and includes ashes from a coals ranging in rank from bituminous to lignite. The characterizations of these ashes include standard tests (LOI, Foam Index), as well as more detailed characterizations of their surface areas, porosity, extractability and adsorption behavior. The ultimate goal is, by better characterizing the material, to enable broadening the range of applications for coal fly ash re-use beyond the current main market as a pozzolanic agent for concretes. The potential for high carbon-content fly ashes to substitute for activated carbons is receiving particular attention. The work performed to date has already revealed how very different the surfaces of different ashes produced by the same utility can be, with respect to polarity of the residual carbon. This can help explain the large variations in acceptability of these ashes as concrete additives.

  4. Investigation on Agropellet Combustion in the Fluidized Bed

    NASA Astrophysics Data System (ADS)

    Isemin, R. L.; Konayahin, V. V.; Kuzmin, S. N.; Zorin, A. T.; Mikhalev, A. V.

    Agricultural wastes (straw, sunflower or millet husk, etc.) are difficult to use as fuel because of low bulk density and relatively big ash content with a low melting point. It is possible to produce agropellets of agricultural wastes which are suggested to combust in a fluidized bed of pellets alone, their char particles and ash. The characteristics of the process of fluidization of agropellets are investigated at room temperature. The experiments on agropellet combustion in a fluidized bed are carried out in an experimental set-up. The results of the experiments have shown that in such a bed the pellets produced of straw and millet husk combust with the same rate as those of wood though the latter contain 8.76 - 19.4 times less ash. The duration of combustion of the same portion of straw pellets in a fluidized bed is 3.74 - 7.01 times less than the duration of combustion of cut straw in a fixed bed. Besides, the movement of agropellets prevents agglomeration and slagging of a boiler furnace.

  5. Fine and ultrafine particles generated during fluidized bed combustion of different solid fuels

    SciTech Connect

    Urciuolo, M.; Barone, A.; D'Alessio, A.; Chirone, R.

    2008-12-15

    The paper reports an experimental study carried out with a 110-mm ID fluidized bed combustor focused on the characterization of particulates formation/emission during combustion of coal and non-fossil solid fuels. Fuels included: a bituminous coal, a commercial predried and granulated sludge (GS), a refuse-derived fuel (RDF), and a biomass waste (pine seed shells). Stationary combustion experiments were carried out analyzing the fate of fuel ashes. Fly ashes collected at the combustor exhaust were characterized both in terms of particle size distribution and chemical composition, with respect to both trace and major elements. Tapping-Mode Atomic Force Microscopy (TM-AFM) technique and high-efficiency cyclone-type collector devices were used to characterize the size and morphology of the nanometric-and micronic-size fractions of fly ash emitted at the exhaust respectively. Results showed that during the combustion process: I) the size of the nanometric fraction ranges between 2 and 65 nm; ii) depending on the fuel tested, combustion-assisted attrition or the production of the primary ash particles originally present in the fuel particles, are responsible of fine particle generation. The amount in the fly ash of inorganic compounds is larger for the waste-derived fuels, reflecting the large inherent content of these compounds in the parent fuels.

  6. Oxy-combustion of biomass in a circulating fluidized bed

    NASA Astrophysics Data System (ADS)

    Kosowska-Golachowska, Monika; Kijo-Kleczkowska, Agnieszka; Luckos, Adam; Wolski, Krzysztof; Musiał, Tomasz

    2016-03-01

    The objective of this study was to investigate combustion characteristics of biomass (willow, Salix viminalis) burnt in air and O2/CO2 mixtures in a circulating fluidized bed (CFB). Air and oxy-combustion characteristics of wooden biomass in CFB were supplemented by the thermogravimetric and differential thermal analyses (TGA/DTA). The results of conducted CFB and TGA tests show that the composition of the oxidizing atmosphere strongly influences the combustion process of biomass fuels. Replacing N2 in the combustion environment by CO2 caused slight delay (higher ignition temperature and lower maximum mass loss rate) in the combustion of wooden biomass. The combustion process in O2/CO2 mixtures at 30% and 40% O2 is faster and shorter than that at lower O2 concentrations.

  7. Direct combustion of olive cake using fluidized bed combustor

    SciTech Connect

    Khraisha, Y.H.; Hamdan, M.A.; Qalalweh, H.S.

    1999-05-01

    A fluidized bed combustor of 0.146 m diameter and 1 m length was fabricated from stainless steel to burn olive cake. Initially, and in order to obtain fluidization, the system was operated under cold conditions using a sand with particle size in the range of 500 to 710 microns. The continuous combustion experiments were carried out under controlled conditions, such that the effects of bed temperature, olive cake feed rate, fluidization velocity, and particle size on combustion efficiency and flue gas composition were investigated. It was found that the combustion efficiency decreases with the bed temperature, fluidization velocity, and the feed rate, while it increases with the particle size used. Further, the gas products analysis carried out using a gas chromatography analyzer have shown a nonmeasured amount of SO{sub 2}, and small amounts of CO. Finally, the temperature distribution along the bed indicated that the temperature throughout the bed is fairly uniform, demonstrating a good mixing of reactants, which is important for efficient combustion.

  8. Decontamination of combustion gases in fluidized bed incinerators

    DOEpatents

    Leon, Albert M.

    1982-01-01

    Sulfur-containing atmospheric pollutants are effectively removed from exit gas streams produced in a fluidized bed combustion system by providing a fluidized bed of particulate material, i.e. limestone and/or dolomite wherein a concentration gradient is maintained in the vertical direction. Countercurrent contacting between upwardly directed sulfur containing combustion gases and descending sorbent particulate material creates a concentration gradient across the vertical extent of the bed characterized in progressively decreasing concentration of sulfur, sulfur dioxide and like contaminants upwardly and decreasing concentration of e.g. calcium oxide, downwardly. In this manner, gases having progressively decreasing sulfur contents contact correspondingly atmospheres having progressively increasing concentrations of calcium oxide thus assuring optimum sulfur removal.

  9. Fluidized bed combustion apparatus and method of operating same

    SciTech Connect

    Williams, R.M.

    1987-02-03

    This patent describes a coal burning boiler having a dense bed column with a closed end and opening into a combustion chamber, and a source of coal. The improvement described here comprises: (a) coal processing mill means adapted to receive coal from the source and having a first outlet conduit connected to a the dense bed column adjacent the closed end and a second outlet conduit connected to the dense bed column spaced from the connection of the first outlet conduit to the dense bed column; (b) means supplying air into the coal processing mill means for stripping fine particulate fractions and delivering the same into the first outlet conduit for injection into the dense bed column; (c) means in the second outlet conduit connection operable to feed coarse particulate fractions into the dense bed column for supplying coarse coal fractions into the column spaced from the injection of fines into the column; and (d) air supply means connected into the dense bed column adjacent the closed end of the dense bed column for fluidizing the fine and coarse coal fractions in the dense bed column.

  10. Combustion of sponge iron plant wastes -- Char and fly ash in FBC boilers

    SciTech Connect

    Rajavel, M.; Muthukrishnan, M.; Banerjee, M.; Natarajan, R.

    1997-12-31

    Coal based sponge iron plants generate large quantity of waste materials in the form of kiln char and fly ash. This material has a very little fuel value owing to the fact that it contains a large percentage of ash and it is almost free from volatiles. Added to this, wide size range of the kiln rejects makes it practically impossible to burn in conventional firing. However, it is realized that the overall economy of the sponge iron plant is likely to be greatly enhanced if the char, the fly ash and a considerable quantity of coal fines, separated in the coal preparation plant, can be utilized. The only possible way to gainfully use these fuels is by fluidized bed combustion. Extensive tests were conducted with these fuels in bubbling fluidized bed combustion test facilities at BHEL, Tiruchirapalli, India. The presentation highlights the experience gained with the above waste fuels in BHEL test facilities and discusses the findings which were subsequently used to design large size FBC boilers.

  11. Bed material agglomeration during fluidized bed combustion. Technical progress report, January 1, 1995--March 31, 1995

    SciTech Connect

    Brown, R.C.; Dawson, M.R.; Smeenk, J.L.

    1995-04-01

    Experiments performed support the hypothesis that a reducing atmosphere during fluidized bed coal combustion contributes to the formation of agglomerates. Reducing conditions are imposed by controlling the amount of combustion air supplied to the combustor, 50% of theoretical in these experiments. These localized reducing conditions may arise from either poor lateral bed mixing or oxygen-starved conditions due to the coal feed locations. Deviations from steady-state operating conditions in bed pressure drop may be used to detect agglomerate formation. Interpretation of the bed pressure drop was made more straightforward by employing a moving average difference method. During steady-state operation, the difference between the moving point averages should be close to zero, within {plus_minus}0.03 inches of water. Instability within the combustor, experienced once agglomerates begin to form, can be recognized as larger deviations from zero, on the magnitude of {plus_minus}0.15 inches of water.

  12. Pressurized fluidized-bed combustion technology exchange workshop

    SciTech Connect

    ,

    1980-04-01

    The pressurized fluidized-bed combustion technology exchange workshop was held June 5 and 6, 1979, at The Meadowlands Hilton Hotel, Secaucus, New Jersey. Eleven papers have been entered individually into EDB and ERA. The papers include reviews of the US DOE and EPRI programs in this area and papers by Swedish, West German, British and American organizations. The British papers concern the joint program of the USA, UK and FRG at Leatherhead. The key factor in several papers is the use of fluidized bed combustors, gas turbines, and steam turbines in combined-cycle power plants. One paper examines several combined-cycle alternatives. (LTN)

  13. Coal-feeding mechanism for a fluidized bed combustion chamber

    DOEpatents

    Gall, Robert L.

    1981-01-01

    The present invention is directed to a fuel-feeding mechanism for a fluidized bed combustor. In accordance with the present invention a perforated conveyor belt is utilized in place of the fixed grid normally disposed at the lower end of the fluidized bed combustion zone. The conveyor belt is fed with fuel, e.g. coal, at one end thereof so that the air passing through the perforations dislodges the coal from the belt and feeds the coal into the fluidized zone in a substantially uniform manner.

  14. Characterization of products from fluidized-bed combustion of coal.

    PubMed

    Bednarik, V; Vondruska, M; Sild, M; Vondruskova, E

    2000-11-01

    The technology of fluidized-bed combustion (FBC) of coal generates byproducts that have a series of unique characteristics and potential uses in technological practice. In this study, the products of fluidized-bed combustion (FBC-P) of coal derived from Moravian heat stations, a.s. Zlin, Cinergy Global Resources, Czech Republic, were characterized. Particular attention was paid to determining the chemical composition of FBC-P, the content of polycyclic aromatic hydrocarbons (PAHs) and toxic metals in the water leachates of these FBC-P, the content of unburned carbon, the capability of FBC-P to solidify with water and form a solid matrix, and the method for discovering optimum mixing water content for FBC-P solidification. The results suggest that one of the qualitatively more important means of utilizing FBC-P could be their application during solidification/stabilization (S/S) of wastes, particularly wastewater treatment sludges.

  15. Circulating fluid bed technology within Combustion Engineering Inc.

    SciTech Connect

    Treff, P.J.; Maitland, J.E.

    1995-12-31

    As the worldwide trend for more flexible, cost-effective CFB technology continues as an alternative to pulverized coal and combined cycle steam generation, Combustion Engineering Inc. has drawn on original scientific work and the operating history of numerous BFBs and CFBs worldwide as reported in publicly available literature to introduce many product enhancements for its next generation of circulating fluid bed boilers. The issues of in-furnace surface versus external fluid bed heat exchanger applicability, cyclone and loop seal design, refractory system design and operating requirements, and the suitability of regenerative air heaters for CFB applications will be among the topics discussed in this paper as Combustion Engineering Inc. answers the challenge to continuously advance CFB steam generation.

  16. Material handling systems for the fluidized-bed combustion boiler at Rivesville, West Virginia

    NASA Technical Reports Server (NTRS)

    Branam, J. G.; Rosborough, W. W.

    1977-01-01

    The 300,000 lbs/hr steam capacity multicell fluidized-bed boiler (MFB) utilizes complex material handling systems. The material handling systems can be divided into the following areas: (1) coal preparation; transfer and delivery, (2) limestone handling system, (3) fly-ash removal and (4) bed material handling system. Each of the above systems are described in detail and some of the potential problem areas are discussed. A major potential problem that exists is the coal drying system. The coal dryer is designed to use 600 F preheated combustion air as drying medium and the dryer effluent is designed to enter a hot electrostatic precipitator (730 F) after passage through a cyclone. Other problem areas to be discussed include the steam generator coal and limestone feed system which may have operating difficulties with wet coal and/or coal fines.

  17. Bed material agglomeration during fluidized bed combustion. Technical progress report, September 30, 1992--December 31, 1992

    SciTech Connect

    Brown, R.C.; Dawson, M.R.; Noble, S.

    1993-02-01

    The purpose of this project is to determine the physical and chemical reactions which led to the undesired agglomeration of bed material during fluidized bed combustion and to relate these reactions to specific causes. Survey of industrial-scale fluidized bed combustors is being conducted to determine the occurrence of bed agglomeration and the circumstances under which agglomeration took place. This task should be finished by the end of February. Samples of bed material, agglomerate material, and boiler deposits are being requested from boiler operators as part of the survey. Once received, these sample will be analyzed to determine chemical and mineralogic composition. The bulk chemical determination will be performed using x-ray fluorescence and inductively coupled plasma-optical emission (ICP). Mineralogy will be detected by x-ray diffraction (XRD). Chemical and mineral reactions will be determined by scanning electron microscopy, optical microscopy, and electron microprobe.

  18. Four Rivers second generation Pressurized Circulating Fluidized Bed Combustion Project

    SciTech Connect

    Holley, E.P.; Lewnard, J.J.; von Wedel, G.; Richardson, K.W.; Morehead, H.T.

    1995-04-01

    Air Products has been selected in the DOE Clean Coal Technology Round V program to build, own, and operate the first commercial power plant using second generation Pressurized Circulating Fluidized Bed (PCFB) combustion technology. The four Rivers Energy Project (Four Rivers) will produce up to 400,000 lb/hr steam, or an equivalent gross capacity of 95 MWe. The unit will be used to repower an Air Products chemicals manufacturing facility in Calvert City, Kentucky.

  19. Bed material agglomeration during fluidized bed combustion. Technical progress report, January 1, 1993--March 31, 1993

    SciTech Connect

    Brown, R.C.; Dawson, M.R.; Noble, S.D.

    1993-04-01

    The purpose of this project is to determine the physical and chemical reactions which lead to the undesired agglomeration of bed material during fluidized bed combustion and to relate these reactions to specific causes. A survey of agglomeration and deposit formation in industrial fluidized bed boilers is in progress. Preliminary results indicate that at least five boilers were experiencing some form of bed material agglomeration. In these instances it was observed that large particles were forming within the bed which were larger that the feed. Four operators could confirm that the larger bed particles had formed due to bed particles sticking together or agglomerating. Deposit formation was reported at nine sites with these deposits being found most commonly at coal feed locations and in cyclones. Other deposit locations included side walls and return loops. Examples of these agglomerates and deposits have been received from five of the surveyed facilities. Also during this quarter, a bulk sample of Illinois No. 6 coal was obtained from the Fossil Energy Program at Ames Laboratory here at Iowa State University and prepared for combustion tests. This sample was first ground to a top-size of 3/8`` using a jaw crusher then a size fraction of 3/8`` {times} 8 (US mesh) was then obtained by sieving using a Gilson Test-Master. This size fraction was selected for the preliminary laboratory-scale experiments designed to simulate the dense bed conditions that exist in the bottom of CFB combustors. To ensure uniformity of fuel composition among combustion runs, the sized coal was riffled using, a cone and long row method and stored in bags for each experiment. During this quarter additional modifications were made to achieve better control of fluidization regimes and to aid in monitoring the hydrodynamic and chemical conditions within the reactor.

  20. Physicochemical characterizations of limestone for fluidized-bed coal combustion

    SciTech Connect

    Fuller, E.L. Jr.; Yoos, T.R. III; Walia, D.S.

    1981-05-01

    This study is an investigation of the physicochemical characteristics of three limestone samples, Quincy limestone (-20 + 60), Franklin limestone (-12 + 30), and Franklin limestone (-6 + 16), currently being tested at Oak Ridge National Laboratory for use in a fluidized-bed coal combustion unit. By correlating the chemistry, mineralogy, and surface area of these samples with empirical data obtained at Argonne National Laboratory, the sulfur capture ability and performance of these limestones can be loosely predicted. X-ray fluorescence and neutron activation analysis revealed a very high calcium content and very low concentrations of other elements in the three samples. X-ray diffraction patterns and petrographic examination of the limestone grains detected essentially no dolomite in the Quincy limestone or the fine Franklin limestone samples. The coarse Franklin limestone sample showed dolomite to be present in varying amounts up to maximum of 2.75%. Limited surface chemistry investigations of the samples were undertaken. Limestone and dolostone resources of the Tennessee Valley Authority region are widespread and abundant, and judged sufficient to meet industrial demand for many years. No problems are anticipated in securing limestone or dolostone supplies for a commercial fluidized-bed combustion plant in the Tennessee Valley Authority region. Transportation facilities and costs for limestone or dolostone will influence the siting of such a commercial fluidized-bed combustion plant. The most promising location in the Tennessee Valley Authority region at this time is Paducah, Kentucky.

  1. Task 3.8 - pressurized fluidized-bed combustion

    SciTech Connect

    1995-03-01

    The focus of this work on pressurized fluidized-bed combustion (PFBC) is the development of sorbents for in-bed alkali control. The goal is to generate fundamental process information for development of a second-generation PFBC. Immediate objectives focus on the performance of sulfur sorbents, fate of alkali, and the Resource Conservation and Recovery Act (RCRA) heavy metals. The studies reported here focus on emission control strategies applied in the bed. Data from shakedown testing, alkali sampling, sulfur sorbent performance tests, and refuse-derived fuel (RDF) and lignite combustion tests are presented in detail. Initial results from the characterization of alkali gettering indicate that in-bed getters can remove a significant amount of alkali from the bed. Using kaolin as a sorbent, sodium levels in the flue gas were reduced from 3.6 ppm to less than 0.22 ppm. Sulfur was also reduced by 60% using the kaolin sorbent. Preliminary sulfur sorbent testing, which was designed to develop a reliable technique to predice sorbent performance, indicate that although the total sulfur capture is significantly lower than that observed in a full-scale PFBC, the emission trends are similar. RDF and RDF-lignite fuels had combustion efficiencies exceeding 99.0% in all test cases. Sulfur dioxide emission was significantly lower for the RDF fuels than for lignite fuel alone. Nitrogen oxide emission was also lower for the RDF-based fuels than for the lignite fuel. Both emission gases were well below current regulatory limits. Carbon monoxide and hydrocarbon emissions appeared to be slightly higher for the fuels containing RDF, but were below 9 ppm for the worst case. Analysis of volatile organic compound emission does not indicate an emission problem for these fuels. Chromium appears to be the only RCRA metal that might present some disposal problem; however, processing of the RDF with the wet resource recovery method should reduce chromium levels. 2 refs., 13 figs., 15 tabs.

  2. Speciation and mobility of cadmium in straw and wood combustion fly ash.

    PubMed

    Hansen, H K; Pedersen, A J; Ottosen, L M; Villumsen, A

    2001-10-01

    Two fly ashes from biomass combustion have been analysed regarding cadmium speciation and mobility. A fly ash from straw combustion contained 10 mg Cd/kg dry matter, and around 50% of the cadmium was leachable in water. The possible main speciation of cadmium in this fly ash was CdCl2. When adding this fly ash to agricultural soil a threat for groundwater contamination and plant uptake is existing. A fly ash from wood chip combustion had 28.6 mg Cd/kg dry matter. In this fly ash, the cadmium was bound more heavily, with only small amounts of cadmium leached in mild extractants. A possible speciation of cadmium in this fly ash was as oxide or as CdSiO3. Long-term effects and accumulation of cadmium could be a problem when adding this fly ash to agricultural or forest soils.

  3. Combustion of textile residues in a packed bed

    SciTech Connect

    Ryu, Changkook; Phan, Anh N.; Sharifi, Vida N.; Swithenbank, Jim

    2007-08-15

    Textile is one of the main components in the municipal waste which is to be diverted from landfill for material and energy recovery. As an initial investigation for energy recovery from textile residues, the combustion of cotton fabrics with a minor fraction of polyester was investigated in a packed bed combustor for air flow rates ranging from 117 to 1638 kg/m{sup 2} h (0.027-0.371 m/s). Tests were also carried out in order to evaluate the co-combustion of textile residues with two segregated waste materials: waste wood and cardboard. Textile residues showed different combustion characteristics when compared to typical waste materials at low air flow rates below 819 kg/m{sup 2} h (0.186 m/s). The ignition front propagated fast along the air channels randomly formed between packed textile particles while leaving a large amount of unignited material above. This resulted in irregular behaviour of the temperature profile, ignition rate and the percentage of weight loss in the ignition propagation stage. A slow smouldering burn-out stage followed the ignition propagation stage. At air flow rates of 1200-1600 kg/m{sup 2} h (0.272-0.363 m/s), the bed had a maximum burning rate of about 240 kg/m{sup 2} h consuming most of the combustibles in the ignition propagation stage. More uniform combustion with an increased burning rate was achieved when textile residues were co-burned with cardboard that had a similar bulk density. (author)

  4. Reduced bed agglomeration by co-combustion biomass with peat fuels in a fluidized bed

    SciTech Connect

    Karin Lundholm; Anders Nordin; Marcus Oehman; Dan Bostroem

    2005-12-01

    Fluidized bed combustion is an energy conversion technology that is very suitable for biomass combustion because of its fuel flexibility and low process temperatures. However, agglomeration of bed material may cause severe operating problems. To prevent or at least reduce this, peat has been suggested as an additive to the main fuels. Nevertheless, the characteristics of peat fuels vary and there is limited information of the effect of different peat fuels and of the mechanisms behind the agglomeration prevention. The objectives of the present work were therefore to: (I) quantify the potential positive effect by co-combustion peat with forest fuels in terms of initial agglomeration temperatures; (ii) determine the amount of peat fuel that is needed to significantly reduce the agglomeration tendencies; and, if possible, (iii) elucidate the governing mechanisms. The results showed that all peat fuels prevented agglomeration in the studied interval of 760-1020{sup o}C and even as little as 5% peat fuel was found to have significant effects. The results also indicated that the mechanism of the agglomeration prevention varies between different peat fuels. Possible mechanisms are the minerals in the peat fuel retain alkali, which then is either elutriated up from the bed or captured in the bed; calcium and other refractory elements increase the melting temperature and thereby counteract the melting of alkali; and sulfur reacts with alkali metals and the alkali sulfates is either elutriated up from the bed or prevents agglomeration by increased melting temperature and lowered viscosity. Results from elemental analysis of the coating on bed particles showed that all mixtures with peat fuel resulted in a decreased or unchanged fraction of potassium and an increased fraction of aluminum in the coatings. The results also indicated a complex relationship between the fuel inorganic contents and the agglomeration process. 21 refs., 6 figs., 5 tabs.

  5. EFFECTS OF IRON CONTENT IN COAL COMBUSTION FLY ASHES ON SPECIATION OF MERCURY

    EPA Science Inventory

    The paper discusses the effects of iron content in coal combustion fly ashes on speciation of mercury. (NOTE: The chemical form of mercury species in combustion flue gases is an important influence on the control of mercury emissions from coal combustion). The study focused on th...

  6. International energy technology assessment: Atmospheric fluidized-bed combustion

    NASA Astrophysics Data System (ADS)

    Krishnan, R. P.; Johnsson, K. O.

    1982-04-01

    A survey was made of atmospheric fluidized bed combustion (AFBC) research and development and commercial activities in foreign countries. These activities indicate a broad interest in the process largely because of its flexibility in burning a wide range of coals and low grade fuels. The conclusion is made that AFBC is a viable system and is in the process of being confirmed on a commercial scale for industrial heat and power generation. A number of organizations in the United States and western Europe are offering fluidized bed package boilers, with some form of commercial guarantees. The major uncertainties of the process lie in the areas of coal and sorbent handling systems, availability of reliable construction materials; the system's ability to meet varying load demands; reduced sorbent requirements; and improved carbon utilization. Research and development programs in these areas are being pursued.

  7. Element associations in ash from waste combustion in fluidized bed

    SciTech Connect

    Karlfeldt Fedje, K.; Rauch, S.; Cho, P.; Steenari, B.-M.

    2010-07-15

    The incineration of MSW in fluidized beds is a commonly applied waste management practice. The composition of the ashes produced in a fluidized bed boiler has important environmental implications as potentially toxic trace elements may be associated with ash particles and it is therefore essential to determine the mechanisms controlling the association of trace elements to ash particles, including the role of major element composition. The research presented here uses micro-analytical techniques to study the distribution of major and trace elements and determine the importance of affinity-based binding mechanisms in separate cyclone ash particles from MSW combustion. Particle size and the occurrence of Ca and Fe were found to be important factors for the binding of trace elements to ash particles, but the binding largely depends on random associations based on the presence of a particle when trace elements condensate in the flue gas.

  8. Fluidization, combustion and emission behavior of biomass in fluidized bed combustion units

    SciTech Connect

    Kaeferstein, P.; Tepper, H.; Gohla, M.; Reimer, H.

    1997-12-31

    Gaseous components were measured over the height and the cross section inside a circulating fluidized bed riser with a thermal power of 60 kW. The combustion behavior of lignite (German brown coal), hard coal, biomass (China reed), and sewage sludge was investigated. The burn-out behavior was investigated by in-situ and real time measurement of the oxygen consumption using solid electrolyte sensor probes within a bubbling fluidized bed combustor with 15 kW thermal power. Non-uniform oxygen concentration profiles were found over the small riser cross-section which differed for the various fuels. The feed location and the fuel distribution also influences the horizontal oxygen profile. The reasons for the non-uniformity of the horizontal oxygen concentration profile are the combustion of volatile matter and the recirculation of char near the walls. A simulation model was developed to calculate the hydrodynamics and the oxygen consumption for the difference fuels inside the CFBC riser.

  9. Method and equipment for treatment of fuel for fluidized bed combustion

    SciTech Connect

    Beranek, J.; Cermak, J.; Dobrozemsky, J.; Fibinger, V.

    1982-04-20

    The invention relates to the method and equipment for treatment of fuel for fluidized bed combustion, which includes drying, classification and crushing of the fuel. The method for treatment of fuel comprises mixing the fuel with hot ash removed from the fluidized bed combustor and drying said mixture in a fluidized bed dryer in which the velocity of the fluidization fluid equals or is lower than the minimum fluidization velocity of particles in the fluidized bed combustor. The equipment for treatment of fuel comprises a bunker, crusher and dryer, comprising a fluidized bed dryer provided with appropriate piping for interconnection of the fluidized bed dryer, fluidized bed combuster, fuel bunker and crusher.

  10. Hydrodynamic model of advanced pressurized fluidized bed combustion

    SciTech Connect

    Horio, Masayuki; Lei, H.W.

    1997-12-31

    A hydrodynamic model was developed for the advanced pressurized fluidized bed combustion (A-PFBC) process. The particular system investigated here is composed of a pressurized circulating fluidized bed (PCFB) for coal gasification/desulfurization and a PCFB for combustion with the gas-solid counter-current flow through the two PCFBs. One of the most important parameters may be the material seal height (MSH) in the downcomer connecting the gasifier/desulfurizer and the combustor, which is thought to strongly influence the safe and stable operation of the process. In this mode, MSH was determined according to the pressure balance between the gasifier/desulfurizer and the combustor. The solid flux in the lower dense region of the two PCFBs was estimated by considering the clustering suspension and core-annulus flow. The mean cluster size and voidage in the cluster phase were predicted by the cluster size model of Horio-Ito (1996). Solid flux of the gasifier and combustor was calculated based on mass balances of limestone, char and ash in the system. Based on this model, the whole pressure profile loop in the system was predicted, and the effects of operating conditions on MSH between the gasifier and the combustor were investigated. The feasibility of the A-PCFB system with PCFBs both for the gasifier/desulfurizer and for the combustor was successfully confirmed.

  11. Electric utility second-generation pressurized fluidized bed combustion plants

    SciTech Connect

    Robertson, A. ); Bonk, D. )

    1992-01-01

    In the search for a more efficient, less costly, and more environmentally responsible method for generating electrical power from coal, research and development has turned to advanced pressurized fluidized bed combustion (PFBC) and coal gasification technologies. A logical extension of this work is the second-generation PFBC plant, which incorporates key components of each of these technologies. In this new type of plant, coal is devolatilized/carbonized before it is injected into the PFB combustor bed, and the low-Btu fuel gas produced by this process is burned in a gas turbine topping combustor. By integrating coal carbonization with PFB coal/char combustion, gas turbine inlet temperatures higher than 1149{degrees}C (2100{degrees}F) can be achieved. The carbonizer, PFB combustor, and particulate-capturing hot gas cleanup systems operate at 871{degrees}C (1600{degrees}F), permitting sulfur capture by lime-based sorbents and minimizing the release of coal contaminants to the gases. This paper presents the performance and economics of this new type of plant and provides a brief overview of the pilot plant test programs being conducted to support its development.

  12. Characterization of fuels for atmospheric fluidized bed combustion

    SciTech Connect

    Daw, C.S. ); Rowley, D.R.; Perna, M.A. . Research Center); Stallings, J.W. ); Divilio, R.J. )

    1990-01-01

    The Electric Power Research Institute (EPRI) has sponsored a fuels characterization program for the past several years with the intention of assisting utilities and boiler manufacturers in evaluating fuel quality impact on atmospheric fluidized bed combustion (AFBC) performance. The goal has been to provide an improved framework for making fuel switching decisions and consolidating operating experience. Results from this program include a set of bench-scale testing procedures, a fuel characterization data base, and a performance simulation model that links fuel characteristics to combustion performance. This paper reviews the major results of the fuels characterization program. The testing procedures, data base, and performance simulation models are briefly described and their application illustrated with examples. Performance predictions for the B W 1-ft{sup 2} bench-scale AFBC and the Tennessee Valley Authority (TVA) 20 MW(e) AFBC Pilot Plant are compared with actual test data. The relationship of coal rank to combustion is discussed. 11 refs., 12 figs., 5 tabs.

  13. Coal Combustion Residual Beneficial Use Evaluation: Fly Ash Concrete and FGD Gypsum Wallboard

    EPA Pesticide Factsheets

    This page contains documents related to the evaluation of coal combustion residual beneficial use of fly ash concrete and FGD gypsum wallboard including the evaluation itself and the accompanying appendices

  14. Development of second-generation pressurized fluidized bed combustion process

    SciTech Connect

    Wolowodiuk, W.; Robertson, A.; Bonk, D.

    1995-12-01

    Under the sponsorship of the United States Department of Energy, Foster Wheeler Development Corporation, and its team members, Westinghouse, Gilbert/Commonwealth, and the Institute of Gas Technology are developing second-generation pressurized fluidized bed combustion technology capable of achieving net plant efficiency in excess of 45 percent based on the higher heating value of the coal. A three-phase program entails design and costing of a 500 MWe power plant and identification of developments needed to commercialize this technology (Phase 1), testing of individual components (Phase 2), and finally testing these components in an integrated mode (Phase 3). This paper briefly describes the results of the first two phases as well as the progress on the third phase. Since other projects which use the same technology are in construction or in negotiation stages-namely, the Power System Development Facility and the Four Rivers Energy Modernization Projects-brief descriptions of these are also included.

  15. Technical evaluation: pressurized fluidized-bed combustion technology

    SciTech Connect

    Miller, S A; Vogel, G J; Gehl, S M; Hanway, Jr, J E; Henry, R F; Parker, K M; Smyk, E B; Swift, W M; Podolski, W F

    1982-04-01

    The technology of pressurized fluidized-bed combustion, particularly in its application to a coal-burning combined-cycle plant, is evaluated by examining the technical status of advanced-concept plant components - boiler system (combustor, air-handling and air-injection equipment, and heat exchangers); solids handling, injection, and ejection system; hot-gas cleanup equipment; instrumentation/control system; and the gas turbine - along with materials of plant construction. Environmental performance as well as energy efficiency are examined, and economic considerations are reviewed briefly. The evaluation concludes with a broad survey of the principal related research and development programs in the United States and other countries, a foreview of the most likely technological developments, and a summary of unresolved technical issues and problems.

  16. METAL FILTERS FOR PRESSURIZED FLUID BED COMBUSTION (PFBC) APPLICATIONS

    SciTech Connect

    M.A. Alvin

    2004-01-02

    Advanced coal and biomass-based gas turbine power generation technologies (IGCC, PFBC, PCFBC, and Hipps) are currently under development and demonstration. Efforts at the Siemens Westinghouse Power Corporation (SWPC) have been focused on the development and demonstration of hot gas filter systems as an enabling technology for power generation. As part of the demonstration effort, SWPC has been actively involved in the development of advanced filter materials and component configuration, has participated in numerous surveillance programs characterizing the material properties and microstructure of field-tested filter elements, and has undertaken extended, accelerated filter life testing programs. This report reviews SWPC's material and component assessment efforts, identifying the performance, stability, and life of porous commercial metal, advanced alloy, and intermetallic filters under simulated, pressurized fluidized-bed combustion (PFBC) conditions.

  17. Partitioning of sodium, chlorine and sulfur during coal and char combustion in a fluid bed

    SciTech Connect

    Bhattacharya, S.P.; He, Y.

    1998-12-31

    Advanced power generation technologies (IGCC, Advanced PFBC) using high moisture low-rank coals require gasification of coal followed by combustion of char in a fluid bed. A study was undertaken to investigate the bed behaviour of char during combustion in a fluid bed. Three high moisture Australian low-rank coals, which are currently used in Victorian power stations, were chosen for this study. These were air dried, ground and sieved to 1--4 mm size. Char was prepared from these coals by devolatilising in a 76-mm diameter spouted bed at 700 C in presence of nitrogen. Char samples were combusted in the same spouted bed under hydrodynamic conditions similar to that in an atmospheric circulating fluid bed at temperatures of 800 C and 900 C. The three coal samples were also combusted under similar conditions to compare with the combustion behaviour of the char. No significant agglomeration problems were observed during combustion of these coals for periods of up to four hours. For one char, the bed defluidized 70 minutes after combustion at 900 C, while the two remaining chars didn`t present any significant agglomeration during the test period of four hours. Ultimate and inorganic analyses were carried out for the coal and char samples before the tests. The bed materials and cyclone ash after each combustion test were analyzed for inorganics and phases using chemical analysis, XRD and DTA techniques. A significant separation of the sodium and chlorine in coal was observed during pyrolysis of the coal to char. During combustion of char, most of the sodium (in char) was captured in the bed materials. This information was used to explain the bed behaviour observed during char combustion. This paper discusses the results and suggest strategies for mitigation of defluidization, that are currently under trial.

  18. SPECIATION OF MERCURY IN THE PRESENCE OF COAL AND WASTE COMBUSTION FLY ASHES

    EPA Science Inventory

    The paper gives results of a study that focused on the oxidation of elemental mercury (Hgo) in the presence of both complex, four-component, model fly ashes, and actual coal combustion fly ashes collected from a pilot plant. Steady-state oxidation of Hgo promoted by the four-com...

  19. Modern fluidized bed combustion in Ostrava-Karvina cogeneration plants

    SciTech Connect

    Mazac, V.; Novacek, A.; Volny, J.

    1995-12-01

    The contemporary situation of our environment claims the sensitive approach to solving effective conversion of energy. Limited supplies of noble fuels and their prices evoke the need to use new combustion technologies of accessible fuels in given region without negative ecological influences. Energoproject participates in the preparation of the two projects in Ostrava-Karvin{acute a} black coal field in Czech Republic. The most effective usage of fuel energy is the combined of electricity and heat. If this physical principle is supported by a pressurized fluidized bed combustion (PFBC) one obtains a high electricity/heat ratio integrated steam-gas cycle on the basis of solid fuel. Cogeneration plant Toebovice is the dominant source (600 MW{sub th}) of Ostrava district heating system (1100 MW{sub th}). The high utilization of the installed output and utilization of the clean, compact and efficient of the PFBC technology is the principal but not the single reason for the selection of the Toebovice power plant as the first cogeneration plant for installation of the PFBC in Czech Republic. The boiler will burn black coal from the neighboring coal basin.

  20. Effect of Bedding Material on Flies, and Behavior and Innate Immunity of Calves Reared in Hutches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dairy calf hutches are often bedded with straw (STR), but sand (SND) and wood shavings (SHV) are becoming more common. The objective was to compare 3 beddings for presence of flies and measures of innate immunity and behavior of calves. Hutches were blocked by location and each of 3 hutches in a blo...

  1. Effect of Bedding Material on Flies, and Behavior and Innate Immunity of Calves Reared in Hutches.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dairy calf hutches are often bedded with straw (STR), but sand (SND) and wood shavings (SHV) are becoming more common. The objective was to compare 3 beddings for presence of flies and measures of innate immunity and behavior of calves. Hutches were blocked by location and each of 3 hutches in a blo...

  2. PCDD/F FORMATION RATES FROM FLY ASH AND METHANE COMBUSTION CARBON SOURCES

    EPA Science Inventory

    The abstract discusses polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD,F) from fly ash and methane combustion carbon sources. (NOTE: PCDD,Fs are formed in trace quantities in combustion processes via two primary mechanisms: de novo synthesis in which they ...

  3. A CFD model for biomass combustion in a packed bed furnace

    NASA Astrophysics Data System (ADS)

    Karim, Md. Rezwanul; Ovi, Ifat Rabbil Qudrat; Naser, Jamal

    2016-07-01

    Climate change has now become an important issue which is affecting environment and people around the world. Global warming is the main reason of climate change which is increasing day by day due to the growing demand of energy in developed countries. Use of renewable energy is now an established technique to decrease the adverse effect of global warming. Biomass is a widely accessible renewable energy source which reduces CO2 emissions for producing thermal energy or electricity. But the combustion of biomass is complex due its large variations and physical structures. Packed bed or fixed bed combustion is the most common method for the energy conversion of biomass. Experimental investigation of packed bed biomass combustion is difficult as the data collection inside the bed is challenging. CFD simulation of these combustion systems can be helpful to investigate different operational conditions and to evaluate the local values inside the investigation area. Available CFD codes can model the gas phase combustion but it can't model the solid phase of biomass conversion. In this work, a complete three-dimensional CFD model is presented for numerical investigation of packed bed biomass combustion. The model describes the solid phase along with the interface between solid and gas phase. It also includes the bed shrinkage due to the continuous movement of the bed during solid fuel combustion. Several variables are employed to represent different parameters of solid mass. Packed bed is considered as a porous bed and User Defined Functions (UDFs) platform is used to introduce solid phase user defined variables in the CFD. Modified standard discrete transfer radiation method (DTRM) is applied to model the radiation heat transfer. Preliminary results of gas phase velocity and pressure drop over packed bed have been shown. The model can be useful for investigation of movement of the packed bed during solid fuel combustion.

  4. Desulfurization in reducing atmosphere and ammonia injection denitrification in a coal-fired fluidized bed combustor with fly-ash recycle

    NASA Astrophysics Data System (ADS)

    Zhong, Zhaoping; Lan, Jixiang; Han, Yongsheng; Wu, Xin; Zheng, Haiyun

    1997-03-01

    With the rising of IGCC and the second generation PFBC-CC, and with the development of technology of staged combustion to lower emission of NOx, the desulfurization efficiency under reducing atmosphere is raised. In this paper, with the application of the fly-ash recycle and two-stage combustion technologies in a fluidized bed combustor, the desulfurization test under reducing atmosphere is described. Meanwhile, ammonia injection test was also conducted. Results show that desulfurization under reducing atmosphere has higher efficiency, and ammonia injection denitrification effect is very perfect.

  5. Method and equipment for treatment of fuel for fluidized bed combustion

    SciTech Connect

    Beranek, J.; Dobrozemsky, J.; Fibinger, V.; Germak, J.

    1983-11-15

    The invention relates to the method and equipment for treatment of fuel for fluidized bed combustion, which includes drying, classification and crushing of the fuel. The method for treatment of fuel comprises mixing the fuel with hot ash removed from the fluidized bed combustor and drying said mixture in a fluidized bed dryer in which the velocity of the fluidization fluid equals or is lower than the minimum fluidization velocity of particles in the fluidized bed combustor. The equipment for treatment of fuel comprises a bunker, crusher and dryer, comprising a fluidized bed dryer provided with appropriate piping for interconnection of the fluidized bed dryer, fluidized bed combustor, fuel bunker and crusher.

  6. JV Task 5 - Evaluation of Residual Oil Fly Ash As A Mercury Sorbent For Coal Combustion Flue Gas

    SciTech Connect

    Robert Patton

    2006-12-31

    The mercury adsorption capacity of a residual oil fly ash (ROFA) sample collected form Florida Power and Light Company's Port Everglades Power Plant was evaluated using a bituminous coal combustion flue gas simulator and fixed-bed testing protocol. A size-segregated (>38 {micro}g) fraction of ROFA was ground to a fine powder and brominated to potentially enhance mercury capture. The ROFA and brominated-ROFA were ineffective in capturing or oxidizing the Hg{sup 0} present in a simulated bituminous coal combustion flue gas. In contrast, a commercially available DARCO{reg_sign} FGD initially adsorbed Hg{sup 0} for about an hour and then catalyzed Hg{sup 0} oxidation to produce Hg{sup 2+}. Apparently, the unburned carbon in ROFA needs to be more rigorously activated in order for it to effectively capture and/or oxidize Hg{sup 0}.

  7. CO₂ carbonation under aqueous conditions using petroleum coke combustion fly ash.

    PubMed

    González, A; Moreno, N; Navia, R

    2014-12-01

    Fly ash from petroleum coke combustion was evaluated for CO2 capture in aqueous medium. Moreover the carbonation efficiency based on different methodologies and the kinetic parameters of the process were determined. The results show that petroleum coke fly ash achieved a CO2 capture yield of 21% at the experimental conditions of 12 g L(-1), 363°K without stirring. The carbonation efficiency by petroleum coke fly ash based on reactive calcium species was within carbonation efficiencies reported by several authors. In addition, carbonation by petroleum coke fly ash follows a pseudo-second order kinetic model.

  8. Chemical and toxicological characterization of organic constituents in fluidized-bed and pulverized coal combustion: a topical report

    SciTech Connect

    Chess, E.K.; Later, D.W.; Wilson, B.W.; Harris, W.R.; Remsen, J.F.

    1984-04-01

    Coal combustion fly ash from both conventional pulverized coal combustion (PCC) and fluidized-bed combustion (FBC) have been characterized as to their organic constituents and microbial mutagenic activity. The PCC fly ash was collected from a commercial utility generating plant using a low sulfur coal. The FBC fly ash was from a bench-scale developmental unit at the Grand Forks Energy Technology Center. Bulk samples of each fly ash were extracted using benzene/methanol and further separated using high performance liquid chromatography (HPLC). Subfractions from the HPLC separation were analyzed by gas chromatography using both element-specific nitrogen-phosphorus detectors and flame ionization detectors. Microbial mutagenicity assay results indicated that the crude organic extracts were mutagenic, and that both the specific activity and the overall activity of the PCC material was greater than that of the FBC material. Comparison of results from assays using S. typhimurium, TA1538NR indicated that nitrated polycyclic aromatic compounds (PAC) were responsible for much of the mutagenic activity of the PCC material. Similar results were obtained for assays of the FBC organic extract with standard and nitroreductase-deficient strains of S. typhimurium, TA100 and TA1538. Mutagenically active HPLC fractions were analyzed using high resolution gas chromatography (HRGC) and GC mass spectrometry (GC/MS), as well as probe inlet low and high resolutions MS. The discovery and identification of nitrated, oxygenated PAC are important because the presence of both nitro and/or keto functionalities on certain PAC has been shown to confer or enhance mutagenic activity.

  9. Co-combustion of agricultural residues with coal in a fluidized bed combustor.

    PubMed

    Ghani, W A W A K; Alias, A B; Savory, R M; Cliffe, K R

    2009-02-01

    Power generation from biomass is an attractive technology that utilizes agricultural residual waste. In order to explain the behavior of biomass-fired fluidized bed incinerator, biomass sources from agricultural residues (rice husk and palm kernel) were co-fired with coal in a 0.15m diameter and 2.3m high fluidized bed combustor. The combustion efficiency and carbon monoxide emissions were studied and compared with those for pure coal combustion. Co-combustion of a mixture of biomass with coal in a fluidized bed combustor designed for coal combustion increased combustion efficiency up to 20% depending upon excess air levels. Observed carbon monoxide levels fluctuated between 200 and 900 ppm with the addition of coal. It is evident from this research that efficient co-firing of biomass with coal can be achieved with minimal modifications to existing coal-fired boilers.

  10. Fluidized-bed combustion process evaluation and program support. Quarterly report, January-March 1980

    SciTech Connect

    Johnson, I.; Podolski, W.F.; Swift, W.M.; Henry, R.F.; Hanway, J.E.; Griggs, K.E.; Herzenberg, C.; Helt, J.E.; Carls, E.L.

    1980-12-01

    Argonne National Laboratory is undertaking several tasks primarily in support of the pressurized fluidized-bed combustion project management team at Morgantown Energy Technology Center. Work is under way to provide fluidized-bed combustion process evaluation and program support to METC, determination of the state of the art of instrumentation for FBC applications, evaluation of the performance capability of cyclones for hot-gas cleaning in PFBC systems, and an initial assessment of methods for the measurement of sodium sulfate dew point.

  11. Impact of the addition of chicken litter on mercury speciation and emissions from coal combustion in a laboratory-scale fluidized bed combustor

    SciTech Connect

    Songgeng Li; Shuang Deng; Andy Wu; Wei-ping Pan

    2008-07-15

    Co-combustion of chicken litter with coal was performed in a laboratory-scale fluidized bed combustor to investigate the effect of chicken litter addition on the partitioning behavior of mercury. Gaseous total and elemental mercury concentrations in the flue gas were measured online, and ash was analyzed for particle-bound mercury along with other elemental and surface properties. The mercury mass balance was between 85 and 105%. The experimental results show that co-combustion of chicken litter decreases the amount of elemental and total mercury in the gas phase. Mercury content in fly ash increases with an increasing chicken litter share. 22 refs., 6 figs., 5 tabs.

  12. Progression in sulfur isotopic compositions from coal to fly ash: Examples from single-source combustion in Indiana

    USGS Publications Warehouse

    Yaofa, Jiang; Elswick, E.R.; Mastalerz, Maria

    2008-01-01

    Sulfur occurs in multiple mineral forms in coals, and its fate in coal combustion is still not well understood. The sulfur isotopic composition of coal from two coal mines in Indiana and fly ash from two power plants that use these coals were studied using geological and geochemical methods. The two coal beds are Middle Pennsylvanian in age; one seam is the low-sulfur ( 5%) Springfield Coal Member of the Petersburg Formation. Both seams have ash contents of approximately 11%. Fly-ash samples were collected at various points in the ash-collection system in the two plants. The results show notable difference in ??34S for sulfur species within and between the low-sulfur and high-sulfur coal. The ??34S values for all sulfur species are exclusively positive in the low-sulfur Danville coal, whereas the ??34S values for sulfate, pyritic, and organic sulfur are both positive and negative in the high-sulfur Springfield coal. Each coal exhibits a distinct pattern of stratigraphic variation in sulfur isotopic composition. Overall, the ??34S for sulfur species values increase up the section in the low-sulfur Danville coal, whereas they show a decrease up the vertical section in the high-sulfur Springfield coal. Based on the evolution of ??34S for sulfur species, it is suggested that there was influence of seawater on peat swamp, with two marine incursions occurring during peat accumulation of the high-sulfur Springfield coal. Therefore, bacterial sulfate reduction played a key role in converting sulfate into hydrogen sulfide, sulfide minerals, and elemental sulfur. The differences in ??34S between sulfate sulfur and pyritic sulfur is very small between individual benches of both coals, implying that some oxidation occurred during deposition or postdeposition. The ??34S values for fly ash from the high-sulfur Springfield coal (averaging 9.7???) are greatly enriched in 34S relative to those in the parent coal (averaging 2.2???). This indicates a fractionation of sulfur isotopes

  13. Solid by-products of coal combustion: Fly ash as a source of industrial minerals

    SciTech Connect

    Bhagwat, S.B.; Rapp, D.M.; Bukowski, J.M.

    1996-12-31

    Fly ash is one of the most important by-products of coal combustion. It is a complex mix of cenospheres, reactive glasses, magnetite and carbon, in addition to minor quantities of other minerals. Fly ash components are determined by the type of coal, the combustion technology, material collection system and the temperature of combustion. The changing mix of coal burned in power plants is increasingly making the fly ash characteristics independent of the locally mined coal. Fly ash is thus becoming a raw material independent of the existence of a local coal mining industry. Currently, about 65 million tons of fly ash are generated annually in the United States. This is equivalent to the crushed stone production of such highly industrialized states as Illinois. Only about twenty percent of the total fly ash are currently used, mostly in low value applications such as road building materials and concrete additions. The fly ash currently represents an environmental and financial liability to electric utilities. The increasingly competitive and boundaryless electricity market in the US increases the incentive to look at fly ash in terms of its individual components and recognize their potential as industrial minerals in the production of value added materials. For example, zeolites and other adsorbents could be produced from reactive glasses, magnetite could be used in pigments and ferrite manufacture, activated carbon could serve in pollution control and cenospheres could be used to make lightweight ceramics. If one begins to look at fly ash as a source of industrial minerals and not as a waste product, this change in perspective could turn a financial and environmental liability into an economic opportunity.

  14. Fluidized bed combustion of low-grade coal and wastes: Research and development

    SciTech Connect

    Borodulya, V.A.; Dikalenko, V.I.; Palchonok, G.I.; Vinogradov, L.M.; Dobkin, S.M.; Telegin, E.M.

    1994-12-31

    Experimental studies were carried out to investigate devolatilization of fuel as single spherical particles of wood, hydrolytic lignin, leather sewage sludge and Belarussian brown coals in a fluidized bed of sand. It is found that the devolatilization process depends on moisture and ash contents in fuel and on the external heat and mass transfer rate. The char combustion occurs largely in the intermediate region. Kinetic parameters of the devolatilization and char combustion are obtained. A low-capacity fluidized bed boiler suitable for combustion of coal and different wastes is described.

  15. Chemical composition and physical properties of filter fly ashes from eight grate-fired biomass combustion plants.

    PubMed

    Lanzerstorfer, Christof

    2015-04-01

    For the handling, treatment and utilization of fly ash from biomass combustion its chemical composition and physical properties are important. In this study eight filter fly ashes from different grate-fired biomass combustion plants were investigated. In fly ash from straw combustion high concentrations of (K) were found, whereas in the fly ash from wood combustion the concentrations of Ca and Mg were higher. The average concentration of PO4(3-) was similar in both types of fly ashes. In all wood fly ashes some measured heavy metal concentrations were above the limits for utilization. The straw fly ashes were much less contaminated and can be utilized. For wood fly ash most parameters showed little variation, except from one fly ash where the dust pre-separator is in poor condition. The average values were: mass median diameter 4.3±0.8 μm, spread of particle size distribution 19±11, particle density 2620±80 kg/m3 and angle of repose 50°±1°. The density of the straw fly ashes is lower (2260±80 kg/m3) and the spread of the size distribution is higher (72±24). For one straw combustion fly ash the values of the mass median diameter and the angle of repose were similar to the values of wood combustion fly ash, for the other straw fly ash the values differed considerably. While the particle size of this fly ash was much smaller, surprisingly the angle of repose was also lower. This can be attributed to the formation of small agglomerates in this fly ash, which were not disintegrated without a certain stress.

  16. Experimental studies on combustion of cattle manure in a fluidized bed combustor

    SciTech Connect

    Annamaial, K.; Ibrahim, M.Y.; Sweeten, J.M.

    1987-06-01

    Manure from cattle feedlots is a renewable energy source which has the potential of supplementing the existing fossil fuels. But the heat content of manure is rather low. Since the fluidized bed combustion technology has been used for the energy conversion of marginal fuels, such a technology is being explored for the combustion of feedlot manure. A fluidized bed combustor of 0.15 m (6 in.) diameter was used for the combustion tests on manure. Experiments were conducted with -20 to +20 percent excess air and at bed temperatures ranging from 600/sup 0/C (1112/sup 0/F) to 800/sup 0/C (1472/sup 0/F). Experimental data revealed that the gasification efficiencies ranged from 90 to 98 percent, while the combustion efficiencies varied from 45 to 85 percent.

  17. Combustion of peanut and tamarind shells in a conical fluidized-bed combustor: a comparative study.

    PubMed

    Kuprianov, Vladimir I; Arromdee, Porametr

    2013-07-01

    Combustion of peanut and tamarind shells was studied in the conical fluidized-bed combustor using alumina sand as the bed material to prevent bed agglomeration. Morphological, thermogravimetric and kinetic characteristics were investigated to compare thermal and combustion reactivity between the biomass fuels. The thermogravimetric kinetics of the biomasses was fitted using the Coats-Redfern method. Experimental tests on the combustor were performed at 60 and 45 kg/h fuel feed rates, with excess air within 20-80%. Temperature and gas concentrations were measured along radial and axial directions in the reactor and at stack. The axial temperature and gas concentration profiles inside the combustor exhibited sensible effects of fuel properties and operating conditions on combustion and emission performance. High (≈ 99%) combustion efficiency and acceptable levels of CO, CxHy, and NO emissions are achievable when firing peanut shells at excess air of about 40%, whereas 60% is more preferable for burning tamarind shells.

  18. Latest Evolution of Oxy-Fuel Combustion Technology in Circulating Fluidized Bed

    NASA Astrophysics Data System (ADS)

    Zhao, C. S.; Duan, L. B.; Chen, X. P.; Liang, C.

    O2/CO2 combustion technology is considered as one of the most promising method to mitigate the greenhouse effect, and the O2/CO2 CFB combustion technology which combines O2/CO2 combustion technology with circulating fluidized bed (CFB) combustion technology will extend both their advantages. The latest research findings on O2/CO2 CFB combustion technology are reviewed, the combustion and pollutant emission characteristics are expatiated, its effects on the boiler design are analyzed, the techno-economic assessment are reported and the key issues are indicated in the paper. O2/CO2 CFB combustion technology has no insolvable bottleneck in its development and due to its economic superiority; it is one of the most important clean coal technologies.

  19. Numerical simulation of gas concentration and dioxin formation for MSW combustion in a fixed bed.

    PubMed

    Sun, Rui; Ismail, Tamer M; Ren, Xiaohan; Abd El-Salam, M

    2015-07-01

    A numerical model was employed to simulate the combustion process in a fixed porous bed of municipal solid waste (MSW). Mass, momentum, energy and species conservation equations of the waste bed were set up to describe the incineration process. The rate of moisture evaporation, volatile matter devolatilization, char combustion, NOx production, and reduction and dioxin formation were calculated and established according to the local thermal conditions and waste property characteristics. Changes in the bed volume during incineration were calculated according to the reaction rate of the process. The simulation results were compared with experimental data, which shows that the incineration process of waste in the fixed bed was reasonably simulated. The simulation results of weight loss and solid temperature in the bed agree with the experimental data, which shows that the waste combustion rate is nearly constant in the middle of the incineration process, and that moisture evaporation takes up most of the time for the overall incineration experiment. The emission of gas species from the bed surface is also agreeably simulated, with O2, CO2, and CO concentrations in flue gas agreeing with the experimental data. The simulation results benefit the understanding of the combustion process in the waste bed as well as the design of incinerator grates.

  20. Fly-ash products from biomass co-combustion for VOC control.

    PubMed

    Kwong, C W; Chao, C Y H

    2010-02-01

    Experiments were conducted in a continuous flow reactor at room temperature to evaluate the elimination of low-concentration toluene in the gas phase to verify if fly-ash products from biomass combustion in an ozonation system could be used in the removal of volatile organic compounds. The fly-ash products from pure biomass combustion (Ash(100)) demonstrated the highest ozonation activities upon the removal of low-concentration toluene (1.5 ppmv), followed by the fly-ash products from co-combustion (Ash(30)) and the coal combustion (Ash(0)). Kinetic experiments showed that the activation energy of the toluene elimination process was substantially reduced with the use of ozone and the reaction intermediates, such as formic acids, aldehydes, etc. Results also showed that the intermediates were reduced with increasing humidity level. The combined use of fly-ash products and zeolite 13X enhanced the removal of toluene to above 90% and suppressed the release of residual ozone and intermediates by holding them in the adsorbed phase.

  1. Co-combustion of textile residues with cardboard and waste wood in a packed bed

    SciTech Connect

    Ryu, Changkook; Phan, Anh N; Sharifi, Vida N; Swithenbank, Jim

    2007-11-15

    The combustible fraction of the municipal waste is mostly bio-derived. Energy recovery of the wastes that cannot be economically recycled is a key part of sustainable energy policy and waste management. Textile residues have high energy content. When burned alone in a packed bed system, however, their combustion efficiency is low due to the irregular propagation of the ignition front and the low burning rates. In order to achieve more efficient combustion of textile residues, a series of co-combustion tests were carried out for various mixture compositions and air flow rates in a packed bed combustor. The combustion performance of these materials was evaluated by using quantitative measures such as ignition rate, burning rate and equivalence ratio. Co-combustion of textile residues with cardboard for a textile fraction of up to 30% achieved satisfactorily high burning rate and low unburned carbon content in the bottom ash. The mixture was more resistant to convective cooling by air, which significantly expanded the range of air flow rate for combustion at high burning rates. In co-combustion with a material that has a very low ignition front speed such as waste wood, the propagation of the ignition front was governed by textile residues. Therefore, the co-combustion of textile residues can be better performed with a material having similar ignition front speeds, in which the two materials simultaneously burn at the ignition front. (author)

  2. JV Task 108 - Circulating Fluidized-Bed Combustion and Combustion Testing of Turkish Tufanbeyli Coal

    SciTech Connect

    Douglas Hajicek; Jay Gunderson; Ann Henderson; Stephen Sollom; Joshua Stanislowski

    2007-08-15

    Two combustion tests were performed at the Energy & Environmental Research Center (EERC) using Tufanbeyli coal from Turkey. The tests were performed in a circulating fluidized-bed combustor (CFBC) and a pulverized coal-fired furnace, referred to as the combustion test facility (CTF). One of the goals of the project was to determine the type of furnace best suited to this coal. The coal is high in moisture, ash, and sulfur and has a low heating value. Both the moisture and the sulfur proved problematic for the CTF tests. The fuel had to be dried to less than 37% moisture before it could be pulverized and further dried to about 25% moisture to allow more uniform feeding into the combustor. During some tests, water was injected into the furnace to simulate the level of flue gas moisture had the fuel been fed without drying. A spray dryer was used downstream of the baghouse to remove sufficient sulfur to meet the EERC emission standards permitted by the North Dakota Department of Health. In addition to a test matrix varying excess air, burner swirl, and load, two longer-term tests were performed to evaluate the fouling potential of the coal at two different temperatures. At the lower temperature (1051 C), very little ash was deposited on the probes, but deposition did occur on the walls upstream of the probe bank, forcing an early end to the test after 2 hours and 40 minutes of testing. At the higher temperature (1116 C), ash deposition on the probes was significant, resulting in termination of the test after only 40 minutes. The same coal was burned in the CFBC, but because the CFBC uses a larger size of material, it was able to feed this coal at a higher moisture content (average of 40.1%) compared to the CTF (ranging from 24.2% to 26.9%). Sulfur control was achieved with the addition of limestone to the bed, although the high calcium-to-sulfur rate required to reduce SO{sub 2} emissions resulted in heat loss (through limestone calcination) and additional ash

  3. Study of instrumentation needs for process control and safety in coal fluidized-bed combustion systems

    SciTech Connect

    Herzenberg, C.L.; Griggs, K.E.; Henry, R.F.; Podolski, W.F.

    1981-02-01

    A study was conducted to evaluate the current state of the art of instrumentation for planned and operating fluidized-bed combustion systems. This study is intended to identify instrumentation needs and serve as a data base for projects to develop this instrumentation. A considerable number of needs for measurements for which presently available instrumentation is not suitable were reported by respondents. The identified deficiencies are presented with the associated physical parameter ranges for FBC processes. New techniques and instrumentation under development, as well as some available alternative instruments, are discussed briefly. Also, newly instituted mechanisms for technical information exchange on instrumentation for fossil energy applications are identified. Development of instruments to meet the identified measurement deficiencies is recommended in order to ensure the feasibility of automatic control of large-scale fluidized-bed combustion systems, and to advance the state of the art of fluidized-bed combustion technology.

  4. Utilization of ventilation air methane as a supplementary fuel at a circulating fluidized bed combustion boiler.

    PubMed

    You, Changfu; Xu, Xuchang

    2008-04-01

    Ventilation air methane (VAM) accounts for 60-80% of the total emissions from coal mining activities in China, which is of serious greenhouse gas concerns as well as a waste of valuable fuel sources. This contribution evaluates the use of the VAM utilization methods as a supplementary fuel at a circulating fluidized bed combustion boiler. The paper describes the system design and discusses some potential technical challenges such as methane oxidation rate, corrosion, and efficiency. Laboratory experimentation has shown that the VAM can be burnt completely in circulated fluidized bed furnaces, and the VAM oxidation does not obviously affect the boiler operation when the methane concentration is less than 0.6%. The VAM decreased the incomplete combustion loss for the circulating fluidized bed combustion furnace. The economic benefit from the coal saving insures that the proposed system is more economically feasible.

  5. Combustion behaviours of tobacco stem in a thermogravimetric analyser and a pilot-scale fluidized bed reactor.

    PubMed

    Yang, Zixu; Zhang, Shihong; Liu, Lei; Li, Xiangpeng; Chen, Hanping; Yang, Haiping; Wang, Xianhua

    2012-04-01

    Despite its abundant supply, tobacco stem has not been exploited as an energy source in large scale. This study investigates the combustion behaviours of tobacco stem in a thermogravimetric analyser (TGA) and a pilot-scale fluidized bed (FB). Combustion characteristics, including ignition and burnout index, and combustion reaction kinetics were studied. Experiments in the FB investigated the effects of different operating conditions, such as primary air flow, secondary air flow and feeding rates, on the bed temperature profiles and combustion efficiency. Two kinds of bed materials cinder and silica sand were used in FB and the effect of bed materials on agglomeration was studied. The results indicated that tobacco stem combustion worked well in the FB. When operation condition was properly set, the tobacco stem combustion efficiency reached 94%. In addition, compared to silica sand, cinder could inhibit agglomeration during combustion because of its high aluminium content.

  6. Pyrolysis and combustion of oil palm stone and palm kernel cake in fixed-bed reactors.

    PubMed

    Razuan, R; Chen, Q; Zhang, X; Sharifi, V; Swithenbank, J

    2010-06-01

    The main objective of this research was to investigate the main characteristics of the thermo-chemical conversion of oil palm stone (OPS) and palm kernel cake (PKC). A series of combustion and pyrolysis tests were carried out in two fixed-bed reactors. The effects of heating rate at the temperature of 700 degrees C on the yields and properties of the pyrolysis products were investigated. The results from the combustion experiments showed that the burning rates increased with an increase in the air flow rate. In addition, the FLIC code was used to simulate the combustion of the oil palm stone to investigate the effect of primary air flow on the combustion process. The FLIC modelling results were in good agreement with the experimental data in terms of predicting the temperature profiles along the bed height and the composition of the flue gases.

  7. Exploratory and basic fluidized-bed combustion studies. Quarterly report, January-March 1980

    SciTech Connect

    Johnson, I.; Myles, K.M.; Swift, W.M.

    1980-12-01

    This work supports development studies for both atmospheric and pressurized fluidized-bed coal combustion. Laboratory and process development studies are aimed at providing needed information on limestone utilization, removal of particulates and alkali metal compounds from the flue gas, control of SO/sub 2/ and trace pollutants emissions, and other aspects of fluidized-bed combustion. This report presents information on: (1) the development of a limestone utilization predictive methodology, (2) studies of particle breakup and elutriation, (3) basic studies on limestone sulfation enhancement by hydration, (4) studies of the kinetics of the hydration process, and (5) an investigation of various hydration process concepts.

  8. Combustion of an oil palm residue with elevated potassium content in a fluidized-bed combustor using alternative bed materials for preventing bed agglomeration.

    PubMed

    Ninduangdee, Pichet; Kuprianov, Vladimir I

    2015-04-01

    Palm kernel shell (PKS) was burned at 45 kg/s and excess air of 20-80% in a fluidized-bed combustor using alumina, dolomite, and limestone as the bed material. Temperature and gas concentrations were recorded along the reactor centerline as well as at stack. A SEM-EDS analysis was performed to investigate morphology and elemental composition of bed particles. An X-ray fluorescence method was used to determine the composition of used/reused bed materials and PM emitted from the combustor at different operating times. Excess air of 40% seems to be most appropriate for burning PKS in this combustor with an alumina bed, whereas 60% excess air is more suitable when using dolomite and limestone, as ensuring high (98.6-98.9%) combustion efficiency and acceptable CO and NO emissions. By using the selected bed materials, bed agglomeration can be prevented in this combustor. However, the bed materials exhibit substantial time-domain changes in physical and chemical properties.

  9. 10 CFR 503.10 - Use of fluidized bed combustion not feasible-general requirement for permanent exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Use of fluidized bed combustion not feasible-general requirement for permanent exemptions. 503.10 Section 503.10 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS NEW FACILITIES General Requirements for Exemptions § 503.10 Use of fluidized bed combustion...

  10. 10 CFR 503.10 - Use of fluidized bed combustion not feasible-general requirement for permanent exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Use of fluidized bed combustion not feasible-general requirement for permanent exemptions. 503.10 Section 503.10 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS NEW FACILITIES General Requirements for Exemptions § 503.10 Use of fluidized bed combustion...

  11. 10 CFR 503.10 - Use of fluidized bed combustion not feasible-general requirement for permanent exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Use of fluidized bed combustion not feasible-general requirement for permanent exemptions. 503.10 Section 503.10 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS NEW FACILITIES General Requirements for Exemptions § 503.10 Use of fluidized bed combustion...

  12. 10 CFR 503.10 - Use of fluidized bed combustion not feasible-general requirement for permanent exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Use of fluidized bed combustion not feasible-general requirement for permanent exemptions. 503.10 Section 503.10 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS NEW FACILITIES General Requirements for Exemptions § 503.10 Use of fluidized bed combustion...

  13. 10 CFR 503.10 - Use of fluidized bed combustion not feasible-general requirement for permanent exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Use of fluidized bed combustion not feasible-general requirement for permanent exemptions. 503.10 Section 503.10 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS NEW FACILITIES General Requirements for Exemptions § 503.10 Use of fluidized bed combustion...

  14. Combustion of various types of residues in a circulating fluidized bed combustor

    SciTech Connect

    Gulyurtlu, I.; Frade, E.; Lopes, H.; Figueiredo, F.; Cabrita, I.

    1997-12-31

    Combustion studies of different wastes alone or mixed were undertaken in an atmospheric circulating fluidized bed. The combustor was operated over a temperature range of 700 to 1,000 C. The residues studied included biomass, tyres, and oil sludges. The main parameters that were investigated are (1) where and how to feed residues, (2) the ratios of amounts of residues when they are burned mixed, (3) air staging, and (4) excess air levels along the riser. The main conclusions are: (1) a large variation in the combustion efficiency was observed depending on the fuel, its particle size and where the fuel was fed in the combustor, (2) in the case of the use of mixture of wastes the utilization of biomass residues as the base fuel increased their combustion efficiency and resulted in very stable combustion conditions, (3) temperature appeared to be still very influential in reducing the levels of unburned carbon and hydrocarbons released from residues, and (4) the air staging in the freeboard improved combustion efficiency by enhancing the combustion of volatiles released from residues in the riser and produced lower emissions of both NO{sub x}. Particles collected in the cyclone and those removed from the bed were also analyzed to determine the levels of heavy metals. When oil sludge was added, high amounts of very fine particles of heavy metals were observed in the combustion gases.

  15. A fixed granular-bed sorber for measurement and control of alkali vapors in PFBC (pressurized fluidized-bed combustion)

    SciTech Connect

    Lee, S.H.D.; Swift, W.M.

    1990-01-01

    Alkali vapors (Na and K) in the hot flue gas from the pressurized fluidized-bed combustion (PFBC) of coal could cause corrosion problems with the gas turbine blades. In a laboratory-scale PFBC test with Beulah lignite, a fixed granular bed of activated bauxite sorbent was used to demonstrate its capability for measuring and controlling alkali vapors in the PFBC flue gas. The Beulah lignite was combusted in a bed of Tymochtee dolomite at bed temperatures ranging from 850 to 875{degrees}C and a system pressure of 9.2 atm absolute. The time-averaged concentration of sodium vapor in the PFBC flue gas was determined from the analysis of two identical beds of activated bauxite and found to be 1.42 and 1.50 ppmW. The potassium vapor concentration was determined to be 0.10 ppmW. The sodium material balance showed that only 0.24% of the total sodium in the lignite was released as vapor species in the PFBC flue gas. This results in an average of 1.56 ppmW alkali vapors in the PFBC flue gas. This average is more than 1.5 orders of magnitude greater than the currently suggested alkali specification limit of 0.024 ppm for an industrial gas turbine. The adsorption data obtained with the activated bauxite beds were also analyzed mathematically by use of a LUB (length of unused bed)/equilibrium section concept. Analytical results showed that the length of the bed, L{sub o} in centimeters, relates to the break through time, {theta}{sub b} in hours, for the alkali vapor to break through the bed as follows: L{sub o} = 33.02 + 1.99 {theta}{sub b}. This formula provides useful information for the engineering design of fixed-bed activated bauxite sorbers for the measurement and control of alkali vapors in PFBC flue gas. 26 refs., 4 figs., 4 tabs.

  16. Technical advances and new opportunities for fluidized bed combustion

    SciTech Connect

    Alliston, M.G.; Kokko, A.; Martin, B.G.; Olofsson, J.

    1997-12-31

    This paper outlines opportunities for new circulating fluidized bed (CFB) boilers, technical considerations in selecting a fluidized bed boiler, and CFB boiler configuration types and sizes. New opportunities for CFBs include fuel opportunities from coke, mine mouth coals, and waste products, and boiler application opportunities in industrial cogeneration, repowering, and developing nations. Technical considerations discussed for boiler selection are fuel flexibility and environmental aspects. Three boiler configurations are briefly described: (1) water-cooled cyclone with water-cooled loopseal, (2) integral cylindrical cyclone and loopseal, and (3) Cylindrical multi-inlet cyclone. CFB scale-up is also briefly discussed. 3 refs., 3 figs.

  17. Characterization of alkali and sulfur sorbents for pressurized fluidized-bed combustion

    SciTech Connect

    Mann, M.D.; Swanson, M.L.; Yagla, S.L.

    1995-12-31

    Pressurized fluidized-bed combustion as applied to combined-cycle power generation has many advantages. Most important are high efficiency, fuel flexibility, and superior emissions control. The University of North Dakota Energy and Environmental Research Center is currently involved in a project to study further improvement of emissions control. The focus of this work has been utilizing in-bed sorbents for capture of sulfur and alkali. Results from the first series of tests utilizing kaolin for capturing alkali are reported, as are results from research to determine sulfur sorbent performance characteristics and to develop predictive techniques of sorbent classification in a pressurized fluidized-bed reactor.

  18. Three dimensional dynamic simulation for bubbling pressurized fluidized bed combustion furnace

    SciTech Connect

    Itami, Teturo; Yoshioka, Susumu; Katori, Takanori; Oki, Katsuya; Sakata, Taro

    1995-12-31

    A mathematical model for the simulation of the pressurized fluidized bed combustion (PFBC) furnaces has been developed to predict three-dimensional distribution of fuel, oxygen and bed temperatures. In this model fuel particles in the bed have been considered as moving diffusively. Three different values of dispersion coefficients of fuel particles, two lateral and one axial coefficients, have been measured using the temperature profile obtained in the scale-down cold model. The model was designed according to the similarity rule, and features a tube-bundle arrangement in the bed. Some of the fuel particles on the bed surface are assumed in the model to be blown out from the bed, and are regarded as unburnt fuel. The ratio of such unburnt fuel particles to the fuel particles concentrated on the bed surface has been estimated using combustion efficiency data obtained in the pilot plant. These dispersion coefficients and the ratio of the unburnt fuel have been used in the proposed simulation model. For the design of the large scale PFBC plants, the present simulation model has been utilized. The number and the location of the fuel feed points have been optimized by taking uniformity of combustion as the design criteria. The criterion for estimating favorable features of combustion has been chosen as minimizing the quantity of unburnt fuel that would move in the freeboard and the high temperature gas line. This paper presents the description and the verification of the proposed model and its application to the furnace design of the large scale PFBC plant.

  19. Investigation of heat transfer and combustion in the advanced fluidized bed combustor (FBC)

    SciTech Connect

    Dr. Seong W. Lee

    1998-10-01

    The objective of this project is to predict the heat transfer and combustion performance in newly-designed fluidized bed combustor (FBC) and to provide the design guide lines and innovative concept for small-scale boiler and furnace. The major accomplishments are summarized.

  20. Wood Combustion Behaviour in a Fixed Bed Combustor

    NASA Astrophysics Data System (ADS)

    Tokit, Ernie Mat; Aziz, Azhar Abdul; Ghazali, Normah Mohd

    2010-06-01

    Waste wood is used as feedstock for Universiti Teknologi Malaysia's newly-developed two-stage incinerator system. The research goals are to optimize the operation of the thermal system to the primary chamber, to improve its combustion efficiency and to minimize its pollutants formation. The combustion process is evaluated with the variation of fuel's moisture content. For optimum operating condition, where the gasification efficiency is 95.53%, the moisture content of the fuel is best set at 17%; giving outlet operating temperature of 550°C and exhaust gas concentrations with 1213 ppm of CO, 6% of CO2 and 14% of O2 respectively. In line to the experimental work, a computational fluid dynamics software, Fluent is used to simulate the performance of the primary chamber. Here the predicted optimum gasification efficiency stands at 95.49% with CO, CO2 and O2 concentrations as 1301 ppm, 6.5% and 13.5% respectively.

  1. [Combustion characteristics of mixed municipal solid waste in thermogravimetric analysis and lab scale fluidized bed].

    PubMed

    Jiang, Fan; Pan, Zhonggang; Liu, Shi; Wang, Haigang

    2002-01-30

    In this paper, thermogravimetric analysis (TGA) and a lab scale fluidized bed facility were used as experimental means. The data in the two different experimental systems were introduced and compared. Experimental results show that the differences of combustion velocity among different wastes in Fluidized Bed(FB) were very small whereas in thermogravimetric analyzer the differences can not be ignored as the value range of combustion velocity variation was between 0.49 and 5.5. It took municipal solid waste 3-3.5 min to burn out in FB, but in thermogravimetric analyzer, the time was 20-25 min. It can be concluded that, in general, the behavior of a mixture of waste in TGA can be expressed by simple combination of individual components of the waste mixtures. Only minor deviations from the rule were observed. In FB, it was found that, for some mixtures, there was interference among the components during FB combustion.

  2. Proceedings of the sixth international conference on fluidized bed combustion. Volume II. Technical sessions

    SciTech Connect

    1980-08-01

    The Sixth International Conference on Fluidized Bed Combustion was held April 9-11, 1980, at the Atlanta Hilton, Atlanta, Georgia. It was sponsored by the US Department of Energy, the Electric Power Research Institute, the US Environmental Protection Agency, and the Tennessee Valley Authority. The papers covered recent developments in atmospheric and pressurized fluidized-bed combustion, especially the design, operation and control of pilot and demonstration plants. The cleanup of combustion products and the erosion, corrosion and fouling of gas turbines was emphasized also. Fifty-five papers from Volume 2 of the proceedings have been entered individually into EDB and ERA; five papers had been entered previously from other sources. (LTN)

  3. Effects of fluidized bed combustion residue on pecan seedling growth and nutrient content. [Carya illinoensis

    SciTech Connect

    Edwards, J.H.; White, A.W. Jr.; Bennett, O.L.

    1985-01-01

    Fluidized bed combustion residue from a calcitic limestone source (FBCRC), a by-product of scrubbing SO/sub 2/ from fossil fuel fired boilers using the FBC technique was evaluated as a source of calcium for pecan (Carya illinoensis (Wang.) K. Koch) seedlings. Fluidized bed combustion residue produced following injection of calcitic limestone into the combustion chamber was more effective in neutralizing soil acidity and increasing extractable soil Ca levels than agricultural calcitic limestone. The Ca concentration in the pecan leaves was increased linearly by Ca rates for both 12- and 24-week growth periods, but stem and petiole Ca concentration was increased linearly for the second 12-week growth period. Macronutrient concentrations were affected by Ca rates for both 12- and 24-week growth periods, but no effect was observed with Ca source. The primary difference was between the control and all other Ca rates.

  4. ESTABLISHMENT OF AN ENVIRONMENTAL CONTROL TECHNOLOGY LABORATORY WITH A CIRCULATING FLUIDIZED-BED COMBUSTION SYSTEM

    SciTech Connect

    Wei-Ping Pan; Kunlei Liu; John T. Riley

    2004-01-01

    The purpose of this report is to summarize the progress made on the project ''Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion (CFBC) System'' in this quarter (September-December of 2003). The main tasks in this quarter consisted of the following four parts. First, all documents for managing this project have been prepared and sent to the Office of Project Management at the US Department of Energy's (DOE's) National Energy Technology Laboratory (NETL). Second, plans for the renovation of space for a new combustion laboratory for the CFBC system has progressed smoothly. Third, considerable progress in the design of the CFBC system has been made. Finally, a lab-scale simulated fluidized-bed combustion facility has been set up in order to make some fundamental investigations of the co-firing of coal with waste materials in the next quarter. Proposed work for the next quarter has been outlined in this report.

  5. Capture of toxic metals by vaious sorbents during fluidized bed coal combustion

    SciTech Connect

    Ho, T.C.; Ghebremeskel, A.; Hopper, J.R.

    1995-12-31

    This study investigated the potential of employing suitable sorbents to capture trace metallic substances during fluidized bed coal combustion. The objectives of the study were to demonstrate the capture process, identify effective sorbents, and characterize the capture efficiency. Experiments were carried out in a 25.4 mm (1 ``) quartz fluidized bed coal combustor enclosed in an electric furnace. In an experiment, a coal sample from the DOE Coal Sample Bank or the Illinois Basin Coal Sample Bank was burned in the bed with a sorbent under various combustion conditions and the amount of metal capture by the sorbent was determined. The metals involved in the study were arsenic, cadmium, lead, mercury and selenium, and the sorbents tested included bauxite, zeolite and lime. The combustion conditions examined included bed temperature, particle size, fluidization velocity (percent excess air), and sorbent bed height. In addition to the experimental investigations, potential metal-sorbent reactions were also identified through performing chemical equilibrium analyses based on the minimization of system free energy.

  6. Lewis Pressurized, Fluidized-Bed Combustion Program. Data and Calculated Results

    NASA Technical Reports Server (NTRS)

    Rollbuhler, R. J.

    1982-01-01

    A 200 kilowatt (thermal), pressurized, fluidized bed (PFB) reactor and research test facility were designed, constructed, and operated. The facility was established to assess and evaluate the effect of PFB hot gas effluent on aircraft turbine engine materials that may have applications in stationary powerplant turbogenerators. The facility was intended for research and development work and was designed to operate over a wide range of conditions. These conditions included the type and rate of consumption of fuel (e.g., coal) and sulfur reacting sorbent material: the ratio of feed fuel to sorbent material; the ratio of feed fuel to combustion airflow; the depth of the fluidized reaction bed; the temperature and pressure in the reaction bed; and the type of test unit that was exposed to the combustion exhaust gases.

  7. ESTABLISHMENT OF AN ENVIRONMENTAL CONTROL TECHNOLOGY LABORATORY WITH A CIRCULATING FLUIDIZED-BED COMBUSTION SYSTEM

    SciTech Connect

    Wei-Ping Pan; Andy Wu; John T. Riley

    2004-10-30

    This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period July 1, 2004 through September 30, 2004. The following tasks have been completed. First, renovation of the new Combustion Laboratory and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building have started. Second, the design if the component parts of the CFBC system have been reviewed and finalized so that the drawings may be released to the manufacturers during the next quarter. Third, the experiments for solid waste (chicken litter) incineration have been conducted using a Thermogravimetric Analyzer (TGA). This is in preparation for testing in the simulated fluidized-bed combustor. The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter has been outlined in this report.

  8. Combustion characteristics of paper and sewage sludge in a pilot-scale fluidized bed.

    PubMed

    Yu, Yong-Ho; Chung, Jinwook

    2015-01-01

    This study characterizes the combustion of paper and sewage sludge in a pilot-scale fluidized bed. The highest temperature during combustion within the system was found at the surface of the fluidized bed. Paper sludge containing roughly 59.8% water was burned without auxiliary fuel, but auxiliary fuel was required to incinerate the sewage sludge, which contained about 79.3% water. The stability of operation was monitored based on the average pressure and the standard deviation of pressure fluctuations. The average pressure at the surface of the fluidized bed decreased as the sludge feed rate increased. However, the standard deviation of pressure fluctuations increased as the sludge feed rate increased. Finally, carbon monoxide (CO) emissions decreased as oxygen content increased in the flue gas, and nitrogen oxide (NOx) emissions were also tied with oxygen content.

  9. ESTABLISHMENT OF AN ENVIRONMENTAL CONTROL TECHNOLOGY LABORATORY WITH A CIRCULATING FLUIDIZED-BED COMBUSTION SYSTEM

    SciTech Connect

    Wei-Ping Pan; Andy Wu; John T. Riley

    2005-01-30

    This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period October 1, 2004 through December 31, 2004. The following tasks have been completed. First, the renovation of the new Combustion Laboratory and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building have proceeded well. Second, the detailed design of supporting and hanging structures for the CFBC was completed. Third, the laboratory-scale simulated fluidized-bed facility was modified after completing a series of pretests. The two problems identified during the pretest were solved. Fourth, the carbonization of chicken waste and coal was investigated in a tube furnace and a Thermogravimetric Analyzer (TGA). The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter has been outlined in this report.

  10. Coal and biomass co-combustion on fluidized bed: Comparison of circulating and bubbling fluidized bed technologies

    SciTech Connect

    Armesto, L.; Cabanillas, A.; Bahillo, A.; Segovia, J.J.; Escalada, R.; Martinez, J.M.; Carrasco, J.E.

    1997-12-31

    The main objective of the proposed paper is to demonstrate the technical feasibility of fluidized bed as a clean technology for the combustion of low grade coal/biomass blends. The raw materials used as fuels in the tests are different blends of the following materials: refuse coal with a heating value of 3,658 kJ/kg (LHV, db) and 79.65% ash content; low grade coal--lignite with a heating value of 19952 kJ/kg (LHV, db), a sulfur content of 10.32% (db) and 23.70% ash content; and biomass--forestry wastes from wood cleaning whose heating value is 19555 kJ/kg (LHV, db). An absorbent, limestone, has been used for reducing sulfur emissions. Co-combustion tests, at the pilot plant level, have been carried out by using two fluidized bed technologies, circulating and bubbling. The object of this paper is to study, in an energy and emission point of view, the clean and efficient use of these resources. The paper collects, analyses and compares combustion test data.

  11. Modeling of devolatilization in circulating fluidized bed combustion

    SciTech Connect

    Stenseng, M.; Lin, W.; Johnsson, J.E.; Dam-Johansen, K.

    1997-12-31

    A mathematical model is developed to describe the devolatilization process in a circulating fluidized bed combustor. The model is a combination of two submodels: single particle devolatilization and fluid dynamics. The single particle model includes the influence of both chemical kinetics and heat transfer on the rate of devolatilization. The results show a good agreement with literature data. The fluid dynamic model describes the main characteristics of a CFB: a dense zone in the bottom, followed by a splash zone and a dilute zone with a core-annulus structure. Each zone is modeled as a number of CSTR`s and the size and number of CSTR`s has been estimated from tracer experiments in an 80 MW{sub th} CFB boiler. It was not possible to evaluate the model against experimental data, but the dependence of particle size on the degree of devolatilization in the dense bed agrees qualitative with the expected behavior. The mode4l shows that the devolatilization mainly occurs in the dense bed.

  12. Modeling of fluidized-bed combustion of coal: Phase II, final reports. Volume V. Appendix: stability and instability in fluidized-bed combustion

    SciTech Connect

    Louis, J.F.; Tung, S.E.

    1980-10-01

    This document is the fifth of the seven volumes series of our Phase II Final Report. The material developed in this volume has not been incorporated into the system model. It will be used as a precursor of a transient model to be developed in the next phase of our model work. There have been various fluidized combustor models of differing complexity and scope published in the literature. Most of these models have identified and predicted - often in satisfactory agreement with results from pilot units - the key steady state combustor characteristics such as the mass of carbon in the bed (carbon loading), the combustion efficiency, the sulfur retention by the solid sorbent and the pollutant (mainly NO/sub x/) emissions. These models, however, cannot be in most instances successfully used to study the extinction and ignition characteristics of the combustor because they are isothermal in structure in the sense that the bed temperature is not an output variable but rather an input one and must be a priori specified. In order to remedy these inadequacies of the previous models, we here present a comprehensive account of the formulation and some typical results of a new nonisothermal model which has been developed in order to study, among other things, the ignition and extinction characteristics of the AFBC units. This model is able to predict the temperature patterns in the bed, the carbon loading, the combustion efficiency and the O/sub 2/ and CO concentration profiles in the combustor for the different design or operational characteristics.

  13. Heavy metal behavior during circulating fluidized bed combustion of willow (Salix)

    SciTech Connect

    Lind, T.; Kauppinen, E.I.; Nilsson, K.; Sfiris, G.; Maenhaut, W.; Huggins, F.E.

    1999-07-01

    The behavior of the heavy metals Cd, Pb, Cu and Zn was studied experimentally at a 35 MW circulating fluidized bed boiler. The fuel was a Swedish willow (Salix) and quartz sand was used as an additional bed material. Almost no Cd was retained in the bottom ash, whereas Zn was clearly enriched in the bottom ash. 15--27% of Pb was in the gas phase downstream of the cyclone at T = 810 C, but less than 3% of Cd, Cu, or Zn. In the convective pass the gas phase Pb reacted with the coarse fly ash particles. Consequently, all the heavy metals were found entirely in the coarse fly ash particles downstream of the convective pass at T = 150 C. The heavy metals were not enriched in the fine fly ash particles. The coarse fly ash particles were large agglomerates consisting of up to thousands of submicron primary particles. These agglomerates were very effective in capturing volatile heavy metals into the coarse fly ash fraction hindering their condensation and subsequent enrichment in the fine particles.

  14. The satellite formation flying in lab: PROBA-3/ASPIICS metrology subsystems test-bed

    NASA Astrophysics Data System (ADS)

    Capobianco, G.; Loreggia, D.; Fineschi, S.; Focardi, M.; Bemporad, A.; Casti, M.; Noce, V.; Landini, F.; Baccani, C.; Pancrazzi, M.; Romoli, M.; Massone, G.; Nicolini, G.; Buckley, S.; O'Neill, K.; Cernica, I.; Purica, M.; Budianu, E.; Thizy, C.; Servaye, J.-S.; Mechmech, I.; Renotte, Etienne

    2016-07-01

    Formation flying is one of the most promising techniques for the future of astronomy and astrophysics from the space. The capabilities of the rockets strongly affect the dimensions and the weights of telescopes and instrumentation to be launched. Telescopes composed by several smallest satellites in formation flying, could be the key for build big space telescopes. With this aim, the ESA PROBA-3 mission will demonstrate the capabilities of this technology, maintaining two satellites aligned within 1 mm (longitudinal) when the nominal distance between the two is of around 144m. The scientific objective of the mission is the observation of the solar corona down to 1.08 solar radii. The Coronagraph Spacecraft (CSC) will observe the Sun, when the second spacecraft, the Occulter Spacecraft (OSC) will work as an external occulter, eclipsing to the CSC the sun disk. The finest metrology sub-systems, the Shadow Position Sensors (SPS) and the Occulter Position Sensor Emitters (OPSE) identifying respectively the CSC-Sun axis and the formation flying (i.e., CSC-OSC) axis will be considered here. In particular, this paper is dedicated to the test-bed for the characterization, the performance analysis and the algorithms capabilities analysis of the both the metrology subsystems. The test-bed is able to simulate the different flight conditions of the two spacecraft and will give the opportunity to check the response of the subsystems in the conditions as close as possible to the flight ones.

  15. The simulation of influence of different coals on the circulating fluidized bed Boiler's combustion performance

    NASA Astrophysics Data System (ADS)

    Yong, Yumei; Lu, Qinggang

    2003-05-01

    The combustion performance of the boiler largely depends on the coal type. Lots of experimental research shows that different fuels have different combustion characteristics. It is obvious that fuel will change the whole operating performance of Circulating Fluidized Bed Combustion (CFBC). We know even in a pilot-scale running boiler, the measurement of some parameters is difficult and costly. Therefore, we developed the way of simulation to evaluate the combustion performance of Chinese coals in CFB. The simulation results show that, different coals will result in different coal particle diameter and comminution depending on their mineral component and the change will affect the distribution of ash in CFBC system. In a word, the computational results are in accordance with experimental results qualitatively but there are some differences quantitatively.

  16. Atmospheric fluidized bed combustion of municipal solid waste: test program results

    SciTech Connect

    Preuit, L C; Wilson, K B

    1980-05-01

    Air classified municipal solid waste (MSW) was fired in an atmospheric fluidized bed combustor at low excess air to simulate boiler conditions. The 7 ft/sup 2/ combustor at Combustion Power Company's energy laboratory in Menlo Park, CA, incorporates water tubes for heat extraction and recycles elutriated particles to the bed. System operation was stable while firing processed MSW for the duration of a 300-h test. Low excess air, low exhaust gas emissions, and constant bed temperature demonstrated feasibility of steam generation from fluidized bed combustion of MSW. During the 300-h test, combustion efficiency averaged 99%. Excess air was typically 44% while an average bed temperature of 1400/sup 0/F and an average superficial gas velocity of 4.6 fps were maintained. Typical exhaust emission levels were 30 ppM SO/sub 2/, 160 ppM NO/sub x/, 200 ppM CO, and 25 ppM hydrocarbons. No agglomeration of bed material or detrimental change in fluidization properties was experienced. A conceptual design study of a full scale plant to be located at Stanford University was based on process conditions from the 300-h test. The plant would produce 250,000 lb/hr steam at the maximum firing rate of 1000 tons per day (TPD) processed MSW. The average 800 TPD firing rate would utilize approximately 1200 TPD raw MSW from surrounding communities. The Stanford Solid Waste energy Program was aimed at development of a MSW-fired fluidized bed boiler and cogeneration plant to supply most of the energy needs of Stanford University.

  17. Trends in the Rare Earth Element Content of U.S.-Based Coal Combustion Fly Ashes.

    PubMed

    Taggart, Ross K; Hower, James C; Dwyer, Gary S; Hsu-Kim, Heileen

    2016-06-07

    Rare earth elements (REEs) are critical and strategic materials in the defense, energy, electronics, and automotive industries. The reclamation of REEs from coal combustion fly ash has been proposed as a way to supplement REE mining. However, the typical REE contents in coal fly ash, particularly in the United States, have not been comprehensively documented or compared among the major types of coal feedstocks that determine fly ash composition. The objective of this study was to characterize a broad selection of U.S. fly ashes of varied geological origin in order to rank their potential for REE recovery. The total and nitric acid-extractable REE content for more than 100 ash samples were correlated with characteristics such as the major element content and coal basin to elucidate trends in REE enrichment. Average total REE content (defined as the sum of the lanthanides, yttrium, and scandium) for ashes derived from Appalachian sources was 591 mg kg(-1) and significantly greater than in ashes from Illinois and Powder River basin coals (403 and 337 mg kg(-1), respectively). The fraction of critical REEs (Nd, Eu, Tb, Dy, Y, and Er) in the fly ashes was 34-38% of the total and considerably higher than in conventional ores (typically less than 15%). Powder River Basin ashes had the highest extractable REE content, with 70% of the total REE recovered by heated nitric acid digestion. This is likely due to the higher calcium content of Powder River Basin ashes, which enhances their solubility in nitric acid. Sc, Nd, and Dy were the major contributors to the total REE value in fly ash, based on their contents and recent market prices. Overall, this study shows that coal fly ash production could provide a substantial domestic supply of REEs, but the feasibility of recovery depends on the development of extraction technologies that could be tailored to the major mineral content and origins of the feed coal for the ash.

  18. Atmospheric behaviour of oil-shale combustion fly ash in a chamber study

    NASA Astrophysics Data System (ADS)

    Teinemaa, Erik; Kirso, Uuve; Strommen, Michael R.; Kamens, Richard M.

    There are huge world deposits of oil shale, however, little is known about the fate of atmospheric oil-shale combustion fly ash. In the present work, oil-shale combustion fly-ash aerosol was investigated under simulated daytime and nighttime conditions. Fly-ash particles collected from the Baltic Power Plant (Estonia) were injected directly to a 190 m 3 outdoor Teflon film chamber. The initial concentration of particles was in the range from 15 to 20 mg/m 3. Particle size distributions were monitored continuously by various optical and electrical devices. During the course of an experiment the particle phase was collected on filters, and the gas phase was collected using denuders. The initial aerosol mass concentration decreased quickly due to the deposition of larger particles. Since fine particles dominated the count distribution, the change in aerosol number concentration was less significiant than the mass concentration over time. Experimental data showed a bimodal particle size distribution with maximums at about 0.07 and 4 μm. SEM images of aerosol particles also provided particle shape and size distribution information. The respirable fraction of particles, which contributes most to the health effects of the aerosol, significantly increased during the experiment, being 25% by mass immediately after the injection of fly ash and achieving 65% at the end of the experiment. Results of CG/MS analysis confirm the presence of different polycyclic aromatic hydrocarbons (PAHs) in the particle phase of the aerosol. Some of the individual compounds included phenanthrene, fluoranthene, pyrene, benz(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, and benzo(a)pyrene. Several PAHs were found in the gas phase of the chamber after fly ash had aged for 2 h, indicating that PAHs desorbed from the particles over time.

  19. Temporal measurements and kinetics of selenium release during coal combustion and gasification in a fluidized bed.

    PubMed

    Shen, Fenghua; Liu, Jing; Zhang, Zhen; Yang, Yingju

    2016-06-05

    The temporal release of selenium from coal during combustion and gasification in a fluidized bed was measured in situ by an on-line analysis system of trace elements in flue gas. The on-line analysis system is based on an inductively coupled plasma optical emission spectroscopy (ICP-OES), and can measure concentrations of trace elements in flue gas quantitatively and continuously. The results of on-line analysis suggest that the concentration of selenium in flue gas during coal gasification is higher than that during coal combustion. Based on the results of on-line analysis, a second-order kinetic law r(x)=0.94e(-26.58/RT)(-0.56 x(2) -0.51 x+1.05) was determined for selenium release during coal combustion, and r(x)=11.96e(-45.03/RT)(-0.53 x(2) -0.56 x+1.09) for selenium release during coal gasification. These two kinetic laws can predict respectively the temporal release of selenium during coal combustion and gasification with an acceptable accuracy. Thermodynamic calculations were conducted to predict selenium species during coal combustion and gasification. The speciation of selenium in flue gas during coal combustion differs from that during coal gasification, indicating that selenium volatilization is different. The gaseous selenium species can react with CaO during coal combustion, but it is not likely to interact with mineral during coal gasification.

  20. Chemical Characterization of Waste Fuel for Fluidized Bed Combustion

    NASA Astrophysics Data System (ADS)

    Claesson, F.; Skrifvars, B.-J.; Elled, A.-L.; Johansson, A.

    Combustible waste is very heterogeneous and the variation in chemical composition is of great significance for the performance of the combustors in terms of boiler availability and power efficiency. For example, the content of alkali, Chlorine and sulfur affect agglomeration, fouling and corrosion mechanisms, which often limits the steam data and requires counteracts such as soot blowing and outages. An increased knowledge on favorable levels and ratios of fuel components are therefore highly important when developing waste combustors, both existing and future. However, to be able to make good predictions of reactions, reliable fuel analyses are a necessity and they are difficult to perform because of the heterogeneity of waste. As a consequence, it is also difficult to complete pro-active measure to reduce unwanted reactions.

  1. EFFECTS OF FLY ASH ON MERCURY OXIDATION DURING POST COMBUSTION CONDITIONS

    SciTech Connect

    Glenn A. Norton; Hongqun Yang; Robert C. Brown; Dennis L. Laudal; Grant E. Dunham; John Erjavec; Joseph M. Okoh

    2002-01-31

    Tests were performed in simulated flue gas streams using fly ash from the electrostatic precipitators of two full-scale utility boilers. One fly ash was from a Powder River Basin (PRB) coal, while the other was from Blacksville coal. Elemental Hg was injected upstream from samples of fly ash loaded onto filters housed in an oven at 120 or 180 C. Concentrations of oxidized and elemental Hg downstream from the filters were determined using the Ontario Hydro method. The gas stream composition and whether or not ash was present in the gas stream were the two most important variables affecting Hg oxidation. The presence of HCl, NO, NO{sub 2}, and SO{sub 2} were all important with respect to Hg oxidation, with NO{sub 2} and HCl being the most important. The presence of NO suppressed Hg oxidation in these tests. Although the two fly ashes were chemically and mineralogically diverse, there were generally no large differences in catalytic potential (for oxidizing Hg) between them. Similarly, no ash fraction appeared to be highly catalytic relative to other ash fractions. This includes fractions enriched in unburned carbon and fractions enriched in iron oxides. Although some differences of lesser magnitude were observed in the amount of oxidized Hg formed, levels of oxidized Hg generally tracked well with the surface areas of the different ashes and ash fractions. Therefore, although the Blacksville fly ash tended to show slightly more catalytic activity than the PRB fly ash, this could be due to the relatively high surface area of that ash. Similarly, for Blacksville fly ash, using nonmagnetic ash resulted in more Hg oxidation than using magnetic ash, but this again tracked well with the relative surface areas of the two ash fractions. Test results suggest that the gas matrix may be more important in Hg oxidation chemistry than the fly ash composition. Combustion tests were performed in which Blacksville and PRB fly ashes were injected into filtered (via a baghouse with

  2. Pulsed atmospheric fluidized bed combustion. Quarterly technical progress report, July 1992--September 1992

    SciTech Connect

    Not Available

    1992-10-01

    The design of the Pulsed Atmospheric Fluidized Bed Combustor (PAFBC) as described in the Quarterly Report for the period April--June, 1992 was reviewed and minor modifications were included. The most important change made was in the coal/limestone preparation and feed system. Instead of procuring pre-sized coal for testing of the PAFBC, it was decided that the installation of a milling system would permit greater flexibility in the testing with respect to size distributions and combustion characteristics in the pulse combustor and the fluid bed. Particle size separation for pulse combustor and fluid bed will be performed by an air classifier. The modified process flow diagram for the coal/limestone handling system is presented in Figure 1. The modified process flow diagrams of the fluidized bed/steam cycle and ash handling systems are presented in Figures 2 and 3, respectively.

  3. Effect of unburned carbon content in fly ash on the retention of 12 elements out of coal-combustion flue gas.

    PubMed

    Bartonová, Lucie; Cech, Bohumír; Ruppenthalová, Lucie; Majvelderová, Vendula; Juchelková, Dagmar; Klika, Zdenek

    2012-01-01

    The aim of this study was to evaluate whether unburned carbon particles present in fly ash can help in the retention of S, Cl, Br, As, Se, Cu, Ni, Zn, Ga, Ge, Rb, and Pb out of flue gas during the coal combustion at fluidised-bed power station where the coal was combusted along with limestone. The competitive influence of 10%-25% CaO in fly ashes on the distribution of studied elements was studied as well to be clear which factor governs behaviour of studied elements. Except of S (with significant association with CaO) and Rb and Pb (with major affinity to Al2O3) the statistically significant and positive correlation coefficients were calculated for the relations between unburned carbon content and Br (0.959), Cl (0.957), Cu (0.916), Se (0.898), Ni (0.866), As (0.861), Zn (0.742), Ge (0.717), and Ga (0.588) content. The results suggest that the unburned carbon is promising material in terms of flue gas cleaning even if contained in highly calcareous fly ashes.

  4. Filling abandoned mines with fluidized bed combustion ash grout

    SciTech Connect

    Gray, D.D.; Reddy, T.P.; Black, D.C.; Ziemkiewicz, P.F.

    1998-10-01

    The hydraulic backfilling of abandoned room and pillar coal mines with ash-based grout holds promise as an environmentally beneficial method of ash disposal, capable of preventing acid mine drainage and subsidence. For this scheme to be economically viable, the grout must be sufficiently flowable so that mines can be filled from a small number of boreholes. This paper describes the development and testing of a water-ash-bentonite grout using ash from a coal and gob burning atmospheric pressure fluidized bed combustor. Bentonite was needed to prevent settling which would limit the ability of the grout to spread. Laboratory techniques were devised to measure the rheological parameters of the grout. A static model was developed to predict the maximum distance of spread due to gravity. A field injection of 765 m{sup 3} of grout into an inactive mine panel showed that the grout flows well enough to make hydraulic backfilling feasible.

  5. Method of removing sulfur emissions from a fluidized-bed combustion process

    DOEpatents

    Vogel, Gerhard John; Jonke, Albert A.; Snyder, Robert B.

    1978-01-01

    Alkali metal or alkaline earth metal oxides are impregnated within refractory support material such as alumina and introduced into a fluidized-bed process for the combustion of coal. Sulfur dioxide produced during combustion reacts with the metal oxide to form metal sulfates within the porous support material. The support material is removed from the process and the metal sulfate regenerated to metal oxide by chemical reduction. Suitable pore sizes are originally developed within the support material by heat-treating to accommodate both the sulfation and regeneration while still maintaining good particle strength.

  6. Sampling and instrumentation for fluidized-bed combustion. Annual report, October 1978-September 1979

    SciTech Connect

    Johnson, I.; Podolski, W.F.; Myles, K.M.

    1980-09-01

    In the first section of this report, background information is presented on instrumentation for fluidized-bed combustion, i.e., for process control, scientific investigation, and safety in planned and operating fluidized-bed combustion systems. The objective of this study is to update and extend the fluidized-bed portion of a preceding report, A Study of the State-of-the-Art of Instrumentation for Process Control and Safety in Large-Scale Coal Gasification, Liquefaction, and Fluidized-Bed Combustion Systems, ANL-76-4. The second section of this report describes two prototype mass flow rate instruments installed on the solids feed lines of an existing ANL fluidized-bed combustor. The Fossil Instrumentation Group at ANL designed, fabricated, and installed these instruments in cooperation with Chemical Engineering Division personnel - one on the coal feedline and one on the coal/limestone feedline. Each instrument consisted of a capacitive sensor spoolpiece and an associated preamplifier and signal conditioning. One channel of each instrument provides three outputs. One delivers a density signal while two others deliver two signals for measuring velocity by cross-correlation. Operation was verified by using laboratory signal analyzers to process the signals. The third section of this report summarizes the results of a Spectron Development Laboratory subcontract from ANL to investigate analytical techniques suitable for monitoring the concentration of gaseous alkali compounds in the hot gas stream from a fluidized-bed combustor. It was concluded from the study that the concept of using the Na/sub 2/SO/sub 4/ dew point to detect the onset of hot corrosion conditions is the most attractive of the techniques evaluated.

  7. Meat and bone meal as secondary fuel in fluidized bed combustion

    SciTech Connect

    L. Fryda; K. Panopoulos; P. Vourliotis; E. Kakaras; E. Pavlidou

    2007-07-01

    Meat and Bone Meal (MBM) was co-fired in a laboratory scale fluidized bed combustion (FBC) apparatus with two coals. Several fuel blends were combusted under different conditions to study how primary fuel substitution by MBM affects flue gas emissions as well as fluidized bed (FB) agglomeration tendency. MBM, being a highly volatile fuel, caused significant increase of CO emissions and secondary air should be used in industrial scale applications to conform to regulations. The high N-content of MBM is moderately reflected on the increase of nitrogen oxides emissions which are reduced by MBM derived volatiles. The MBM ash, mainly containing bone material rich in Ca, did not create any noteworthy desulphurization effect. The observed slight decrease in SO{sub 2} emissions is predominantly attributed to the lower sulphur content in the coal/MBM fuel mixtures. The SEM/EDS analysis of bed material samples from the coal/MBM tests revealed the formation of agglomerates of bed material debris and ash with sizes that do not greatly exceed the original bed inventory and thus not problematic. 37 refs., 9 figs., 3 tabs.

  8. Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion System

    SciTech Connect

    Wei-Ping Pan; Yan Cao; Songgeng Li

    2006-04-01

    This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period January 1, 2006 through March 31, 2006. Work was performed on the following activities. First, the fabrication and manufacture of the CFBC Facility were completed. The riser, primary cyclone and secondary cyclone of Circulating Fluidized Bed (CFB) Combustor have been erected. Second, the Mercury Control Workshop and the Grand Opening of Institute for Combustion Science and Environmental Technology (ICSET) were successfully held on February 22 and 23, 2006, respectively. Third, effects of hydrogen chlorine (HCl) and sulfur dioxide (SO{sub 2}) on mercury oxidation were studied in a drop tube reactor. The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter is described in this report.

  9. Trace metal capture by various sorbents during fluidized bed coal combustion

    SciTech Connect

    Ho, T.C.; Ghebremeskel, A.; Wang, K.S.; Hopper, J.R.

    1997-07-01

    This study investigated the potential of employing suitable sorbents to capture toxic trace metallic substances during fluidized bed coal combustion. Metal capture experiments were carried out in a 25.4 mm (1 inch) quartz fluidized bed combustor enclosed in an electric furnace. The metals involved were cadmium, lead, chromium, arsenic and selenium, and the sorbents tested included bauxite, zeolite and lime. In addition to the experimental investigations, potential metal-sorbent reactions were also identified through chemical equilibrium calculations based on the minimization of system free energy. The observed experimental results indicated that metal capture by sorbents can be as high as 88% depending on the metal species and sorbent involved. Results from thermodynamic equilibrium simulations suggested the formation of metal-sorbent compounds such as Pb{sub 2}SiO{sub 4}(s), CdAl{sub 2}O{sub 4}(s) and CdSiO{sub 3}(s) under the combustion conditions.

  10. Trace metal capture by various sorbents during fluidized bed coal combustion

    SciTech Connect

    Ho, T.C.; Ghebremeskel, A.; Hopper, J.R.

    1996-06-01

    Experiments were conducted in a 1-in. quartz fluidized bed combustor enclosed in an electric furnace. Coal samples were burned in the bed with a sorbent under specific combustion conditions and the amount of metal capture by the sorbent determined. Three different cao samples from the Illinois Basin Coal Sample Bank were tested. Metals involved were Cd, Pb, and Cr; the sorbents included bauxite, zeolite, and lime. Potential metal-sorbent reactions were identified. Results indicated that metal capture by sorbent can be as high as 96%, depending on the metal species and sorbent. All 3 sorbents were capable of capturing Pb, zeolite and lime were able to capture Cr, and bauxite was the only sorbent capable of capturing Cd. Thermodynamic equilibrium calculations suggested the formation of metal-sorbent compounds such as Pb{sub 2}SiO{sub 4}, CdAl{sub 2}O{sub 4}, and CdSiO{sub 3} solids under the combustion conditions.

  11. Combustion Characteristics of Lignite Char in a Laboratory-scale Pressurized Fluidized Bed Combustor

    NASA Astrophysics Data System (ADS)

    Murakami, Takahiro; Suzuki, Yoshizo

    In a dual fluidized bed gasifier, the residual char after steam gasification is burnt in riser. The objectives of this work are to clarify the effect of parameters (temperature, pressure, and particle size of lignite char) of char combustion using a laboratory-scale pressurized fluidized bed combustor (PFBC). As a result, the burnout time of lignite char can be improved with increasing operating pressure, and temperature. In addition, the decrease in the particle size of char enhanced the effect on burnout time. The initial combustion rate of the char can be increased with increasing operating pressure. The effect was decreased with increasing operating temperature. However, the effect of operating pressure was slightly changed in small particle size, such as 0.5-1.0 mm. It takes about 20 sec to burn 50% of char in the operating pressure of 0.5 MPa and the particle size of 0.5-1.0 mm.

  12. Activation of immune complement by fly ash particles from coal combustion. [Dogs

    SciTech Connect

    Hill, J.O.; Rothenberg, S.J.; Kanapilly, G.M.; Hanson, R.L.; Scott, B.R.

    1982-06-01

    The interaction of immune complement with fly ash particles from coal combustion was studied in vitro. Fly ash from different coal combustors was incubated for 1 hr with pooled normal dog serum at 37/sup 0/C. The serum supernatants were assayed for complement by a 505 hemolytic (CH/sub 50/) endpoint method. Ash produced by burning one type of coal activated complement with up to 70% of the complement activated at 10 mg ash/ml serum. This activation was concentration dependent and a linear dose-response curve was obtained. Heat treatment and surface area measurements, as well as immunofluorescence studies, suggest that the active component(s) is volatile or heat labile, found on the surface of the particles, and removed by saline or water extraction.

  13. High fire resistance in blocks containing coal combustion fly ashes and bottom ash.

    PubMed

    García Arenas, Celia; Marrero, Madelyn; Leiva, Carlos; Solís-Guzmán, Jaime; Vilches Arenas, Luis F

    2011-08-01

    Fire resistance recycled blocks, containing fly ash and bottom ash from coal combustion power plants with a high fire resistance, are studied in this paper by testing different compositions using Portland cement type II, sand, coarse aggregate and fly ash (up to 50% of total weight) and bottom ash (up to 30% of total weight). The fire resistance, physical-chemical (density, pH, humidity, and water absorption capacity), mechanical (compressive and flexural strength), and leaching properties are measured on blocks made with different proportions of fly ash and bottom ash. The standard fire resistance test is reproduced on 28cm-high, 18cm-wide and 3cm-thick units, and is measured as the time needed to reach a temperature of 180°C on the non-exposed surface of the blocks for the different compositions. The results show that the replacement of fine aggregate with fly ash and of coarse aggregate with bottom ash have a remarkable influence on fire resistance and cause no detriment to the mechanical properties of the product. Additionally, according to the leaching tests, no environmental problems have been detected in the product. These results lead to an analysis of the recycling possibilities of these by-products in useful construction applications for the passive protection against fire.

  14. Improving lithium-ion battery performances by adding fly ash from coal combustion on cathode film

    SciTech Connect

    Dyartanti, Endah Retno; Jumari, Arif Nur, Adrian; Purwanto, Agus

    2016-02-08

    A lithium battery is composed of anode, cathode and a separator. The performance of lithium battery is also influenced by the conductive material of cathode film. In this research, the use of fly ash from coal combustion as conductive enhancer for increasing the performances of lithium battery was investigated. Lithium iron phosphate (LiFePO{sub 4}) was used as the active material of cathode. The dry fly ash passed through 200 mesh screen, LiFePO{sub 4} and acethylene black (AB), polyvinylidene fluoride (PVDF) as a binder and N-methyl-2-pyrrolidone (NMP) as a solvent were mixed to form slurry. The slurry was then coated, dried and hot pressed to obtain the cathode film. The ratio of fly ash and AB were varied at the values of 1%, 2%, 3%, 4% and 5% while the other components were at constant. The anode film was casted with certain thickness and composition. The performance of battery lithium was examined by Eight Channel Battery Analyzer, the composition of the cathode film was examined by XRD (X-Ray Diffraction), and the structure and morphology of the anode film was analyzed by SEM (Scanning Electron Microscope). The composition, structure and morphology of cathode film was only different when fly ash added was 4% of AB or more. The addition of 2% of AB on cathode film gave the best performance of 81.712 mAh/g on charging and 79.412 mAh/g on discharging.

  15. Proceedings of the sixth international conference on fluidized bed combustion. Volume III. Technical sessions

    SciTech Connect

    1980-08-01

    The Sixth International Conference on Fluidized Bed Combustion was held April 9-11, 1980, at the Atlanta Hilton, Atlanta, Georgia. It was sponsored by the US Department of Energy, the Electric Power Research Institute, the US Environmental Protection Agency, and the Tennessee Valley Authority. Forty-five papers from Vol. III of the proceedings have been entered individually into EDB and ERA. Two papers had been entered previously from other sources. (LTN)

  16. Pulsed atmospheric fluidized bed combustion. Technical progress report, January 1992--March 1992

    SciTech Connect

    Not Available

    1992-05-01

    During this first quarter, a lab-scale water-cooled pulse combustor was designed, fabricated, and integrated with old pilot-scale PAFBC test systems. Characterization tests on this pulse combustor firing different kinds of fuel -- natural gas, pulverized coal and fine coal -- were conducted (without fluidized bed operation) for the purpose of finalizing PAFBC full-scale design. Steady-state tests were performed. Heat transfer performance and combustion efficiency of a coal-fired pulse combustor were evaluated.

  17. Proceedings of the Sixth International Conference on Fluidized Bed Combustion. Volume 1. Plenary sessions

    SciTech Connect

    1980-08-01

    The Sixth International Conference on Fluidized Bed Combustion was held at the Atlanta Hilton, Atlanta, Georgia, April 9-11, 1980. The papers in this volume involved presentation of the research and development programs of the US (US DOE, TVA, EPRI and US EPA), United Kingdom, Federal Republic of Germany and the People's Republic of China. Eight papers from Vol. 1 (Plenary Sessions) of the proceedings have been entered individually into EDB and ERA. (LTN)

  18. Design and performance of a fluidized-bed incinerator for TRU combustible wastes

    SciTech Connect

    Meile, L.J.; Meyer, F.G.

    1982-01-01

    Problems encountered in the incineration of glovebox generated waste at Rocky Flats Plant (RFP) led to the development of a fluidized-bed incineration (FBI) system for transuranic (TRU) combustible wastes. Laboratory and pilot-scale testing of the process preceded the installation of an 82-kg/h production demonstration incinerator at RFP. The FBI process is discussed, and the design of the demonstration incinerator is described. Operating experience and process performance for both the pilot and demonstration units are presented.

  19. Environmental, physical and structural characterisation of geopolymer matrixes synthesised from coal (co-)combustion fly ashes.

    PubMed

    Alvarez-Ayuso, E; Querol, X; Plana, F; Alastuey, A; Moreno, N; Izquierdo, M; Font, O; Moreno, T; Diez, S; Vázquez, E; Barra, M

    2008-06-15

    The synthesis of geopolymer matrixes from coal (co-)combustion fly ashes as the sole source of silica and alumina has been studied in order to assess both their capacity to immobilise the potentially toxic elements contained in these coal (co-)combustion by-products and their suitability to be used as cement replacements. The geopolymerisation process has been performed using (5, 8 and 12 M) NaOH solutions as activation media and different curing time (6-48 h) and temperature (40-80 degrees C) conditions. Synthesised geopolymers have been characterised with regard to their leaching behaviour, following the DIN 38414-S4 [DIN 38414-S4, Determination of leachability by water (S4), group S: sludge and sediments. German standard methods for the examination of water, waste water and sludge. Institut für Normung, Berlin, 1984] and NEN 7375 [NEN 7375, Leaching characteristics of moulded or monolithic building and waste materials. Determination of leaching of inorganic components with the diffusion test. Netherlands Normalisation Institute, Delft, 2004] procedures, and to their structural stability by means of compressive strength measurements. In addition, geopolymer mineralogy, morphology and structure have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. It was found that synthesised geopolymer matrixes were only effective in the chemical immobilisation of a number of elements of environmental concern contained in fly ashes, reducing (especially for Ba), or maintaining their leachable contents after the geopolymerisation process, but not for those elements present as oxyanions. Physical entrapment does not seem either to contribute in an important way, in general, to the immobilisation of oxyanions. The structural stability of synthesised geopolymers was mainly dependent on the glass content of fly ashes, attaining at the optimal activation conditions (12 M NaOH, 48 h, 80

  20. Measurement of alkali-vapor emission from pressurized fluidized-bed combustion of Illinois coals

    SciTech Connect

    Lee, S.H.D.; Teats, F.G.; Swift, W.M.; Banerjee, D.D.

    1993-04-01

    Two Illinois Herrin No. 6 coals and one Illinois Springfield No. 5 coal were separately combusted in a laboratory-scale (15-cm dia) pressurized fluidized-bed combustor (PFBC) combined with an alkali sorber. These coals were combusted in a fluidized bed of Tymochtee dolomite at temperatures ranging from 910 to 950{degree}C and a system pressure of 9.2 atm absolute. Alkali-vapor emission (Na and K) in the PFBC flue gas was determined by the analytical activated-bauxite sorber bed technique developed at Argonne National Laboratory. The test results showed that sodium is the major alkali-vapor species present in the PFBC flue gas, and that the level of sodium-vapor emission increases linearly with both Na and Cl contents in the coals. This suggests that the sodium-vapor emission results from direct vaporization of NaCl present in the coals. The measured alkali-vapor concentration (Na + K), 67 to 190 ppbW, is more than 2.5 times greater than the allowable alkali limit of 24 ppb for an industrial gas turbine. Combusting these coals in a PFBC for power generation may require developing a method to control alkali vapors.

  1. Measurement of alkali-vapor emission from pressurized fluidized-bed combustion of Illinois coals

    SciTech Connect

    Lee, S.H.D.; Teats, F.G.; Swift, W.M. ); Banerjee, D.D. )

    1993-01-01

    Two Illinois Herrin No. 6 coals and one Illinois Springfield No. 5 coal were separately combusted in a laboratory-scale (15-cm dia) pressurized fluidized-bed combustor (PFBC) combined with an alkali sorber. These coals were combusted in a fluidized bed of Tymochtee dolomite at temperatures ranging from 910 to 950[degree]C and a system pressure of 9.2 atm absolute. Alkali-vapor emission (Na and K) in the PFBC flue gas was determined by the analytical activated-bauxite sorber bed technique developed at Argonne National Laboratory. The test results showed that sodium is the major alkali-vapor species present in the PFBC flue gas, and that the level of sodium-vapor emission increases linearly with both Na and Cl contents in the coals. This suggests that the sodium-vapor emission results from direct vaporization of NaCl present in the coals. The measured alkali-vapor concentration (Na + K), 67 to 190 ppbW, is more than 2.5 times greater than the allowable alkali limit of 24 ppb for an industrial gas turbine. Combusting these coals in a PFBC for power generation may require developing a method to control alkali vapors.

  2. ESTABLISHMENT OF AN ENVIRONMENTAL CONTROL TECHNOLOGY LABORATORY WITH A CIRCULATING FLUIDIZED-BED COMBUSTION SYSTEM

    SciTech Connect

    Wei-Ping Pan; Andy Wu; John T. Riley

    2005-07-30

    This purpose of this report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period April 1, 2005 through June 30, 2005. The following tasks have been completed. First, the new Combustion Laboratory was occupied on June 15, 2005, and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building is in the final painting stage. Second, the fabrication and manufacturing contract for the CFBC Facility was awarded to Sterling Boiler & Mechanical, Inc. of Evansville, Indiana. Sterling is manufacturing the assembly and component parts of the CFBC system. The erection of the CFBC system is expected to start September 1, 2005. Third, mercury emissions from the cofiring of coal and chicken waste was studied experimentally in the laboratory-scale simulated fluidized-bed combustion facility. The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter is described.

  3. Capture of alkali during pressurized fluidized-bed combustion using in-bed sorbents

    SciTech Connect

    Mann, M.D.; Ludlow, D.K.

    1997-12-31

    The primary focus of this research was the removal of alkali from PFBC flue gases to a level specified by turbine manufactures. The target level was less than 24 ppbw. Several of the aluminosilicate minerals have the potential to capture alkalis, especially sodium and potassium, under conditions typical of fluid-bed operation. Other goals of this work were to investigate the potential for simultaneously removing SO{sub 2} and Cl from the PFBC gas stream. The initial work focused primarily on one class of sorbents, sodalites, with the goal of determining whether sodalites can be used as an in-bed sorbent to simultaneously remove alkali and sulfur. Thermo gravimetric analysis (TGA) was used to study the mechanism of alkali capture using sodalite. Further testing was performed on a 7.6 cm (3-in.)-diameter pressurized fluid-bed reactor (PFBR). Early results indicated that simultaneous removal of alkali and sulfur and/or chlorine was not practical under the conditions for commercial PFBC operations. Therefore, the focus of the latter part of this work was on sorbents that have been shown to capture alkali in other systems. The effectiveness of bauxite and kaolinite to reduce vapor-phase alkali concentrations was determined. In addition to studying the gettering capability of the sorbent, the impact of the getter on operational performance was evaluated. This evaluation included examining potential agglomeration of bed particles, deposition on heat-transfer surfaces, and the bridging and blinding of ceramic candle filters. The focus of this paper is on the work performed on the PFBR.

  4. Experimental study on combustion characteristics and NOX emissions of pulverized anthracite preheated by circulating fluidized bed

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Zhu, Jian-Guo; Lu, Qing-Gang

    2011-08-01

    A 30 kW bench-scale rig of pulverized anthracite combustion preheated by a circulating fluidized bed (CFB) was developed. The CFB riser has a diameter of 90 mm and a height of 1,500 mm. The down-fired combustion chamber (DFCC) has a diameter of 260 mm and a height of 3,000 mm. Combustion experiments were carried out using pulverized anthracite with 6.74% volatile content. This low volatile coal is difficult to ignite and burn out. Therefore, it requires longer burnout time and higher combustion temperature, which results in larger NOX emissions. In the current study, important factors that influence the combustion characteristics and NOX emissions were investigated such as excess air ratio, air ratio in the reducing zone, and fuel residence time in the reducing zone. Pulverized anthracite can be quickly preheated up to 800°C in CFB when the primary air is 24% of theoretical air for combustion, and the temperature profile is uniform in DFCC. The combustion efficiency is 94.2%, which is competitive with other anthracite combustion technologies. When the excess air ratio ranges from 1.26 to 1.67, the coal-N conversion ratio is less than 32% and the NOX emission concentration is less than 371 mg/m3 (@6% O2). When the air ratio in the reducing zone is 0.12, the NOX concentration is 221 mg/m3 (@6% O2), and the coal-N conversion ratio is 21%, which is much lower than that of other boilers.

  5. Combustion characteristics of different parts of corn straw and NO formation in a fixed bed.

    PubMed

    Zhao, Wei; Li, Zhengqi; Wang, Dawei; Zhu, Qunyi; Sun, Rui; Meng, Baihong; Zhao, Guangbo

    2008-05-01

    Experiments with five samples of corn straw were carried out on a one-dimensional bench combustion test rig. The bed temperature distribution and the mass loss of fuel and gas components such as O2, CO, CO2 and NO were measured in the bed. The combustion of corn straw occurred in two stages, ignition front propagation and char oxidation. The average burning rate increased with an increase in the primary air flow until a critical point was reached, beyond which a further increase in the primary air flow resulted in a decreased burning rate. The mean concentration of NO reached a minimum value and then increased with increased primary air flow. The time taken for the drying front to reach the bottom of the bed was 800 s, 700 s, and 500 s; the temperatures in the high bed temperature zones were 900-935 degrees C, 800-850 degrees C and 700-743 degrees C; and the maximum concentrations of NO were 725 ppmv, 1287 ppmv, and 2730 ppmv, for whole corn stalks, hollow corn stalks and flaked corn stalks, respectively. The maximum concentrations of CO and NO were quite different between samples. There was only one peak in the distribution of NO concentration for sample B, but there were two peaks for whole corn stalks and sample A.

  6. Hydration of spent limestone and dolomite to enhance sulfation in fluidized-bed combustion

    SciTech Connect

    Shearer, J.A.; Smith, G.W.; Moulton, D.S.; Turner, C.B.; Myles, K.M.; Johnson, I.

    1980-01-01

    The utilization of CaO in fluidized bed combustion can be markedly increased to reduce the cost and environmental impact of quarrying and disposing of large quantities of solid waste. A new method of treatment of spent bed material to reactivate its SO/sub 2/ capturing ability has been found. Partially sulfated spent overflow material from a fluidized-bed combustor is treated with water and then reintroduced to the combustor as renewed feed that further reacts with SO/sub 2/. This material has sufficient physical integrity, due to the outer layer of CaSO/sub 4/, and high reactivity to make it suitable as a sorbent feedstock. The work reported here details observations on a number of limestones and dolomites reacted in laboratory furnaces under simulated combustion conditions as well as verification of the effectiveness of the method in a 15-cm-ID process development unit scale atmospheric fluidized-bed coal combustor. Initial kinetic studies have also been made on the hydration reaction of partially sulfated limestone. A proposed mechanism of interaction is discussed to explain the enhanced reactivity. Changes in total porosity and pore size distribution in the partially sulfated material due to Ca(OH)/sub 2/ formation and its dehydration serve to open up the particle interior and its residual CaO to further reaction with SO/sub 2/. Almost complete utilization of the available CaO can be achieved by successive applications of this promising new technique.

  7. Atmospheric fluidized bed combustion (AFBC) plants: an operations and maintenance study

    SciTech Connect

    Jack A. Fuller; Harvie Beavers; Robert Bessette

    2006-06-15

    The authors analyzed data from a fluidized bed boiler survey distributed during the spring of 2003 to develop appropriate AFBC (Atmospheric Fluidized Bed Combustion) performance benchmarks. The survey was sent to members of CIBO (Council of Industrial Boiler Owners), who sponsored the survey, as well as to other firms who had an operating AFBC boiler on-site. There were three primary purposes for the collection and analysis of the data contained in this fluidized bed boiler survey: (1) To develop AFBC benchmarks on technical, cost, revenue, and environmental issues; (2) to inform AFBC owners and operators of contemporary concerns and issues in the industry; (3) to improve decision making in the industry with respect to current and future plant start-ups and ongoing operations.

  8. Exploratory and basic fluidized-bed combustion studies. Quarterly report, April-June 1980. [Limestone and dolomite; USA

    SciTech Connect

    Johnson, I.; Myles, K.M.; Swift, W.M.

    1980-12-01

    This work supports the development studies for both atmospheric and pressurized fluidized-bed coal combustion. Laboratory and process development studies are aimed at providing needed information on limestone utilization, removal of particles and alkali metal compounds from the flue gas, control of SO/sub 2/ and trace pollutant emissions, and other aspects of fluidized-bed coal combustion. This report presents information on: (1) the development of a sorbent utilization prediction methodology, (2) studies of factors which affect limestone breakup and elutriation, (3) basic studies of limestone sulfation under combustion conditions, and (4) studies of the kinetics of the hydration of spent limestone.

  9. Pressurized Fluidized Bed Combustion Second-Generation System Research and Development

    SciTech Connect

    A. Robertson; D. Horazak; R. Newby; H. Goldstein

    2002-11-01

    Research is being conducted under United States Department of Energy (DOE) Contract DE-AC21-86MC21023 to develop a new type of coal-fired plant for electric power generation. This new type of plant--called a Second-Generation or Advanced Pressurized Circulating Fluidized Bed Combustion (APCFB) plant--offers the promise of efficiencies greater than 45% (HHV), with both emissions and a cost of electricity that are significantly lower than conventional pulverized-coal-fired plants with scrubbers. The APCFB plant incorporates the partial gasification of coal in a carbonizer, the combustion of carbonizer char in a pressurized circulating fluidized bed boiler (PCFB), and the combustion of carbonizer syngas in a topping combustor to achieve gas turbine inlet temperatures of 2300 F and higher. A conceptual design was previously prepared for this new type of plant and an economic analysis presented, all based on the use of a Siemens Westinghouse W501F gas turbine with projected carbonizer, PCFB, and topping combustor performance data. Having tested these components at the pilot plant stage, the referenced conceptual design is being updated to reflect more accurate performance predictions together with the use of the more advanced Siemens Westinghouse W501G gas turbine and a conventional 2400 psig/1050 F/1050 F/2-1/2 in. steam turbine. This report describes the updated plant which is projected to have an HHV efficiency of 48% and identifies work completed for the October 2001 through September 2002 time period.

  10. ESTABLISHMENT OF AN ENVIRONMENTAL CONTROL TECHNOLOGY LABORATORY WITH A CIRCULATING FLUIDIZED-BED COMBUSTION SYSTEM

    SciTech Connect

    Wei-Ping Pan, Kunlei Liu; John T. Riley

    2004-07-30

    This report presents the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the quarter April 1--June 30, 2004. The following tasks have been completed. First, the final specifications for the renovation of the new Combustion Laboratory and the construction of the CFB Combustor Building have been delivered to the architect, and invitations for construction bids for the two tasks have been released. Second, the component parts of the CFBC system have been designed after the design work for assembly parts of the CFBC system was completed. Third, the literature pertaining to Polychlorinated Dibenzo-p-Dioxins (PCDD) and Polychlorinated Dibenzofurans (PCDF) released during the incineration of solid waste, including municipal solid waste (MSW) and refuse-derived fuel (RDF) have been reviewed, and an experimental plan for fundamental research of MSW incineration on a simulated fluidized-bed combustion (FBC) facility has been prepared. Finally, the proposed work for the next quarter has been outlined in this report.

  11. Experimental study on rice husk combustion in a vortexing fluidized-bed with flue gas recirculation (FGR).

    PubMed

    Duan, Feng; Chyang, Chien-Song; Lin, Chien-Wei; Tso, Jim

    2013-04-01

    Vortexing fluidized-bed combustor (VFBC) has been proven to be an effective equipment in converting biomass wastes into clean energy. This study conducted experiments on rice husk combustion in a VFBC with FGR. The effect of FGR on combustion characteristics is investigated. In addition, the effect of operating variables such as excess oxygen ratio, and in-bed stoichiometric oxygen ratio on the temperature distributions, pollutants emissions, and combustion efficiency are also studied. The results show that the combustion efficiency of rice husk can reach 99% at optimal operation condition. CO emission increases with the in-bed stoichiometric oxygen ratio, but decreases with excess oxygen ratio. NOx emissions show inverse trend, and it can be effectively reduced by using FGR in the VFBC.

  12. Characterization of Combustion and Emission of Several Kinds of Herbaceous Biomass Pellets in a Circulating Fluidized Bed Combustor

    NASA Astrophysics Data System (ADS)

    Li, S. Y.; Teng, H. P.; Jiao, W. H.; Shang, L. L.; Lu, Q. G.

    Characterizations of combustion and emission of four kinds of herbaceous biomass pellets were investigated in a 0.15 MWt circulating fluidized bed. Corn stalk, wheat stalk, cotton stalk and king grass, which are typical herbaceous biomass in China, were chosen for this study. Temperature profile, emission in flue gas and agglomeration were studied by changing the combustion temperature between 750°C and 880°C. The combustion efficiencies are in the range from 97.4% to 99.4%, which are relatively high due to the homogeneous temperature profiles and good circulating fluidization of bed material. Suitable combustion temperatures for the different herbaceous biomass are mainly depended on the emission and bed agglomeration. SO2 and HCl concentrations in flue gas are in direct proportion to the sulfur and chlorine contents of the herbaceous biomass. Agglomeration at the cyclone leg and the loop seal is the main reason for defluidization in the CFB combustor.

  13. Aerodynamic and aerothermodynamic trade-off analysis of a small hypersonic flying test bed

    NASA Astrophysics Data System (ADS)

    Pezzella, Giuseppe

    2011-08-01

    This paper deals with the aerodynamic and aerothermodynamic trade-off analysis aiming to design a small hypersonic flying test bed with a relatively simple vehicle architecture. Such vehicle will have to be launched with a sounding rocket and shall re-enter the Earth atmosphere allowing to perform several experiments on critical re-entry technologies such as boundary-layer transition and shock-shock interaction phenomena. The flight shall be conducted at hypersonic Mach number, in the range 6-8 at moderate angles of attack. In the paper some design analyses are shown as, for example, the longitudinal and lateral-directional stability analysis. A preliminary optimization of the configuration has been also done to improve the aerodynamic performance and stability of the vehicle. Several design results, based both on engineering approach and computational fluid dynamics, are reported and discussed in the paper. The aerodynamic model of vehicle is also provided.

  14. Second-Generation Pressurized Fluidized Bed Combustion: Small gas turbine induustrial plant study

    SciTech Connect

    Shenker, J.; Garland, R.; Horazak, D.; Seifert, F.; Wenglarz, R.

    1992-07-01

    Second-Generation Pressurized Fluidized Bed Combustion (PFBC) plants provide a coal-fired, high-efficiency, combined-cycle system for the generation of electricity and steam. The plants use lime-based sorbents in PFB combustors to meet environmental air standards without back-end gas desulfurization equipment. The second-generation system is an improvement over earlier PFBC concepts because it can achieve gas temperatures of 2100[degrees]F and higher for improved cycle efficiency while maintaining the fluidized beds at 1600[degrees]F for enhanced sulfur capture and minimum alkali release. Second-generation PFBC systems are capable of supplying the electric and steam process needs of industrial plants. The basic second-generation system can be applied in different ways to meet a variety of process steam and electrical requirements. To evaluate the potential of these systems in the industrial market, conceptual designs have been developed for six second-generation PFBC plants. These plants cover a range of electrical outputs from 6.3 to 41.5 MWe and steam flows from 46,067 to 442,337 lb/h. Capital and operating costs have been estimated for these six plants and for equivalent (in size) conventional, coal-fired atmospheric fluidized bed combustion cogeneration plants. Economic analyses were conducted to compare the cost of steam for both the second-generation plants and the conventional plants.

  15. Second-Generation Pressurized Fluidized Bed Combustion: Small gas turbine industrial plant study

    SciTech Connect

    Shenker, J.; Garland, R.; Horazak, D.; Seifert, F.; Wenglarz, R.

    1992-07-01

    Second-Generation Pressurized Fluidized Bed Combustion (PFBC) plants provide a coal-fired, high-efficiency, combined-cycle system for the generation of electricity and steam. The plants use lime-based sorbents in PFB combustors to meet environmental air standards without back-end gas desulfurization equipment. The second-generation system is an improvement over earlier PFBC concepts because it can achieve gas temperatures of 2100{degrees}F and higher for improved cycle efficiency while maintaining the fluidized beds at 1600{degrees}F for enhanced sulfur capture and minimum alkali release. Second-generation PFBC systems are capable of supplying the electric and steam process needs of industrial plants. The basic second-generation system can be applied in different ways to meet a variety of process steam and electrical requirements. To evaluate the potential of these systems in the industrial market, conceptual designs have been developed for six second-generation PFBC plants. These plants cover a range of electrical outputs from 6.3 to 41.5 MWe and steam flows from 46,067 to 442,337 lb/h. Capital and operating costs have been estimated for these six plants and for equivalent (in size) conventional, coal-fired atmospheric fluidized bed combustion cogeneration plants. Economic analyses were conducted to compare the cost of steam for both the second-generation plants and the conventional plants.

  16. ESTABLISHMENT OF AN ENVIRONMENTAL CONTROL TECHNOLOGY LABORATORY WITH A CIRCULATING FLUIDIZED-BED COMBUSTION SYSTEM

    SciTech Connect

    Wei-Ping Pan; Andy Wu; John T. Riley

    2005-04-30

    This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period January 1, 2005 through March 31, 2005. The following tasks have been completed. First, the renovation of the new Combustion Laboratory is nearly complete, and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building is in the final stages. Second, the fabrication and manufacture of the CFBC Facility is being discussed with a potential contractor. Discussions with potential contactor regarding the availability of materials and current machining capabilities have resulted in the modification of the original designs. The selection of the fabrication contractor for the CFBC Facility is expected during the next quarter. Third, co-firing experiments conducted with coal and chicken waste have been initiated in the laboratory-scale simulated fluidized-bed facility. The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter is described in this report.

  17. Analysis of naturally-occurring radionuclides in coal combustion fly ash, gypsum, and scrubber residue samples.

    PubMed

    Roper, Angela R; Stabin, Michael G; Delapp, Rossane C; Kosson, David S

    2013-03-01

    Coal combustion residues from coal-fired power plants can be advantageous for use in building and construction materials. These by-products contain trace quantities of naturally occurring radionuclides from the uranium and thorium series, as well as other naturally occurring radionuclides such as K. Analysis was performed on samples of coal fly ash, flue gas desulfurization, gypsum and scrubber sludges, fixated scrubber sludges, and waste water filter cakes sampled from multiple coal-fired power plants in the United States. The radioactive content of U and Th decay series nuclides was determined using gamma photopeaks from progeny Pb at 352 keV and Tl at 583 keV, respectively; K specific activities were determined using the 1,461 keV photopeak. The samples were hermetically sealed to allow for secular equilibrium between the radium parents and the radon and subsequent progeny. Samples were analyzed in a common geometry using two high purity germanium photon detectors with low energy detection capabilities. The specific activities (Bq kg) were compared to results from literature studies including different building materials and fly ash specific activities. Fly ash from bituminous and subbituminous coals had U specific activities varying from 30-217 Bq kg (mean + 1 s.d. 119 ± 45 Bq kg) and 72-209 Bq kg (115 ± 40 Bq kg), respectively; Th specific activities from 10-120 Bq kg (73 ± 26 Bq kg) and 53-110 Bq kg (81 ± 18 Bq kg), respectively; and K specific activities from 177 to 928 Bq kg (569 ± 184 Bq kg) and 87-303 Bq kg (171 ± 69 Bq kg), respectively. Gypsum samples had U, Th, and K specific activities approximately one order of magnitude less than measured for fly ash samples.

  18. pH-dependent leaching of constituents of potential concern from concrete materials containing coal combustion fly ash.

    PubMed

    Kosson, David S; Garrabrants, Andrew C; DeLapp, Rossane; van der Sloot, Hans A

    2014-05-01

    Current concerns about the environmental safety of coal combustion fly ash have motivated this evaluation of the impact of fly ash use as a cement replacement in concrete materials on the leaching of constituents of potential concern. The chemical effects of fly ash on leaching were determined through characterization of liquid-solid partitioning using EPA Method 1313 for four fly ash materials as well as concrete and microconcrete materials containing 0% (control materials), 25% and 45% replacement of portland cement with the fly ash source. All source materials, concrete formulations and replacement levels are representative of US concrete industry practices. Eluate concentrations as a function of pH were compared to a broader range of available testing results for international concretes and mortars for which the leaching characteristics of the component fly ashes were unknown. The chemistry of the hydrated cement fraction was found to dominate the liquid-solid partitioning resulting in reduced leaching concentrations of most trace metals compared to concentrations from fly ash materials alone. Compared to controls, eluate concentrations of Sb, As, B, Cr, Mo, Se, Tl and V from concrete products containing fly ash were essentially the same as the eluate concentrations from control materials produced without fly ash replacement indicating little to no significant impact on aqueous partitioning.

  19. Gaseous emissions from sewage sludge combustion in a moving bed combustor.

    PubMed

    Batistella, Luciane; Silva, Valdemar; Suzin, Renato C; Virmond, Elaine; Althoff, Chrtistine A; Moreira, Regina F P M; José, Humberto J

    2015-12-01

    Substantial increase in sewage sludge generation in recent years requires suitable destination for this residue. This study evaluated the gaseous emissions generated during combustion of an aerobic sewage sludge in a pilot scale moving bed reactor. To utilize the heat generated during combustion, the exhaust gas was applied to the raw sludge drying process. The gaseous emissions were analyzed both after the combustion and drying steps. The results of the sewage sludge characterization showed the energy potential of this residue (LHV equal to 14.5 MJ kg(-1), db) and low concentration of metals, polycyclic aromatic hydrocarbons (PAH), polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF). The concentration of CO, NOx, BTEX (benzene, toluene, ethylbenzene and xylenes) emitted from the sludge combustion process were lower than the legal limits. The overall sludge combustion and drying process showed low emissions of PCDD/PCDF (0.42 ng I-TEQ N m(-3)). BTEX and PAH emissions were not detected. Even with the high nitrogen concentration in the raw feed (5.88% db), the sludge combustion process presented NOx emissions below the legal limit, which results from the combination of appropriate feed rate (A/F ratio), excess air, and mainly the low temperature kept inside the combustion chamber. It was found that the level of CO emissions from the overall sludge process depends on the dryer operating conditions, such as the oxygen content and the drying temperature, which have to be controlled throughout the process in order to achieve low CO levels. The aerobic sewage sludge combustion process generated high SO2 concentration due to the high sulfur content (0.67 wt%, db) and low calcium concentration (22.99 g kg(-1)) found in the sludge. The high concentration of SO2 in the flue gas (4776.77 mg N m(-3)) is the main factor inhibiting PCDD/PCDF formation. Further changes are needed in the pilot plant scheme to reduce SO2 and particulate matter emissions

  20. Characteristics modeling for supercritical circulating fluidized bed boiler working in oxy-combustion technology

    NASA Astrophysics Data System (ADS)

    Balicki, Adrian; Bartela, Łukasz

    2014-06-01

    Among the technologies which allow to reduce greenhouse gas emission, mainly carbon dioxide, special attention deserves the idea of `zeroemission' technology based on boilers working in oxy-combustion technology. In the paper the results of analyses of the influence of changing two quantities, namely oxygen share in oxidant produced in the air separation unit, and oxygen share in oxidant supplied to the furnace chamber on the selected characteristics of a steam boiler including the degree of exhaust gas recirculation, boiler efficiency and adiabatic flame temperature, was examined. Due to the possibility of the integration of boiler model with carbon dioxide capture, separation and storage installation, the subject of the analysis was also to determine composition of the flue gas at the outlet of a moisture condensation installation. Required calculations were made using a model of a supercritical circulating fluidized bed boiler working in oxy-combustion technology, which was built in a commercial software and in-house codes.

  1. Mineral sequestration of CO(2) by aqueous carbonation of coal combustion fly-ash.

    PubMed

    Montes-Hernandez, G; Pérez-López, R; Renard, F; Nieto, J M; Charlet, L

    2009-01-30

    The increasing CO(2) concentration in the Earth's atmosphere, mainly caused by fossil fuel combustion, has led to concerns about global warming. A technology that could possibly contribute to reducing carbon dioxide emissions is the in-situ mineral sequestration (long term geological storage) or the ex-situ mineral sequestration (controlled industrial reactors) of CO(2). In the present study, we propose to use coal combustion fly-ash, an industrial waste that contains about 4.1 wt.% of lime (CaO), to sequester carbon dioxide by aqueous carbonation. The carbonation reaction was carried out in two successive chemical reactions, first, the irreversible hydration of lime. second, the spontaneous carbonation of calcium hydroxide suspension. A significant CaO-CaCO(3) chemical transformation (approximately 82% of carbonation efficiency) was estimated by pressure-mass balance after 2h of reaction at 30 degrees C. In addition, the qualitative comparison of X-ray diffraction spectra for reactants and products revealed a complete CaO-CaCO(3) conversion. The carbonation efficiency of CaO was independent on the initial pressure of CO(2) (10, 20, 30 and 40 bar) and it was not significantly affected by reaction temperature (room temperature "20-25", 30 and 60 degrees C) and by fly-ash dose (50, 100, 150 g). The kinetic data demonstrated that the initial rate of CO(2) transfer was enhanced by carbonation process for our experiments. The precipitate calcium carbonate was characterized by isolated micrometric particles and micrometric agglomerates of calcite (SEM observations). Finally, the geochemical modelling using PHREEQC software indicated that the final solutions (i.e. after reaction) are supersaturated with respect to calcium carbonate (0.7 < or = saturation index < or = 1.1). This experimental study demonstrates that 1 ton of fly-ash could sequester up to 26 kg of CO(2), i.e. 38.18 ton of fly-ash per ton of CO(2) sequestered. This confirms the possibility to use this

  2. Circulating fluidized bed tehnology in biomass combustion-performance, advances and experiences

    SciTech Connect

    Mutanen, K.I.

    1995-11-01

    Development of fluidized bed combustion (FBC) was started both in North America and in Europe in the 1960`s. In Europe and especially in Scandinavia the major driving force behind the development was the need to find new more efficient technologies for utilization of low-grade fuels like different biomasses and wastes. Both bubbling fluidized bed (BFB) and circulating fluidized bed (CFB) technologies were under intensive R&D,D efforts and have now advanced to dominating role in industrial and district heating power plant markets in Europe. New advanced CFB designs are now entering the markets. In North America and especially in the US the driving force behind the FBC development was initially the need to utilize different types of coals in a more efficient and environmentally acceptable way. The present and future markets seem to be mainly in biomass and multifuel applications where there is benefit from high combustion efficiency, high fuel flexibility and low emissions such as in the pulp and paper industry. The choice between CFB technology and BFB technology is based on selected fuels, emission requirements, plant size and on technical and economic feasibility. Based on Scandinavian experience there is vast potential in the North American industry to retrofit existing oil fired, pulverized coal fired, chemical recovery or grate fired boilers with FBC systems or to build a new FBC based boiler plant. This paper will present the status of CFB technologies and will compare technical and economic feasibility of CFB technology to CFB technology to BFB and also to other combustion methods. Power plant projects that are using advanced CFB technology e.g. Ahlstrom Pyroflow Compact technology for biomass firing and co-firing of biomass with other fuels will also be introduced.

  3. Characterizing and modeling combustion of mild-gasification chars in pressurized fluidized beds

    SciTech Connect

    Daw, C.S.

    1995-10-01

    Oak Ridge National Laboratory (ORNL) is supported by the Morgantown Energy Technology Center (METC) of the Department of Energy (DOE) under FWP-FEAA310 to characterize the fuel properties of liquid and char coproducts from the mild gasification of coal, Because most of the energy content of coals subjected to mild gasification is retained in the byproduct char, efficient and cost-effective utilization of the char is essential in insuring that candidate gasification processes are commercially viable. One potential use for char of particular interest to DOE is pressurized fluidized bed combustion (PFBC). PFBC is of particular interest because it has the potential for 10 to 30 percent greater overall energy efficiency than atmospheric fluidized bed combustion (AFBC), While bench-scale tools and analytical procedures for characterizing fuels for AFBC have been recently demonstrated, no such tools have been reliably demonstrated for PFBC. This report summarizes the results of joint research collaboration between ORNL and B&W that has been directed at modifying the previously developed AFBC fuel characterization procedures to be applicable for mild-gasification chars and PFBC conditions. The specific objectives were to: (1) characterize the combustion reactivity of a selected set of candidate mild- gasification chars at PFB conditions; (2) compare the measured char characteristics with those of more conventional PFBC fuels; (3) modify an AFBC computer code previously developed by B&W and ORNL for the Electric Power Research Institute (EPRI) to predict PFBC performance; and (4) apply the modified code and measured char combustion characteristics to make performance predictions for the candidate chars relative to more conventional fuels.

  4. Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion System

    SciTech Connect

    Wei-Ping Pan; Zhongxian Cheng; Yan Cao; John Smith

    2006-09-30

    This report is to present the progress made on the project entitled ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period July 1, 2006 through September 30, 2006. The following activities have been completed: the steel floor grating around the riser in all levels and the three-phase power supply for CFBC System was installed. Erection of downcomers, loop seals, ash bunker, thermal expansion joints, fuel and bed material bunkers with load cells, rotary air-lock valves and fuel flow monitors is underway. Pilot-scale slipstream tests conducted with bromine compound addition were performed for two typical types of coal. The purposes of the tests were to study the effect of bromine addition on mercury oxidization. From the test results, it was observed that there was a strong oxidization effect for Powder River Basin (PRB) coal. The proposed work for next quarter and project schedule are also described.

  5. West Virginia Geological Survey's role in siting fluidized bed combustion facilities

    USGS Publications Warehouse

    Smith, C.J.; King, Hobart M.; Ashton, K.C.; Kirstein, D.S.; McColloch, G.H.

    1989-01-01

    A project is presented which demonstrates the role of geology in planning and siting a fluidized bed combustion facility. Whenever a project includes natural resource utilization, cooperation between geologists and design engineers will provide an input that could and should save costs, similar to the one stated in our initial premise. Regardless of whether cost reductions stem from a better knowledge of fuel and sorbent availabilities, or a better understanding of the local hydrology, susceptibility to mine-subsidence, or other geologic hazards, the geological survey has a vital role in planning. Input to planning could help the fluidized-bed developer and design-engineer solve some economic questions and stretch the financial resources at their disposal.

  6. The ability of selected pupal parasitoids (Hymenoptera: Pteromalidae) to locate stable fly hosts in a soiled equine bedding substrate.

    PubMed

    Pitzer, Jimmy B; Kaufman, Phillip E; Geden, Christopher J; Hogsette, Jerome A

    2011-02-01

    The ability of Spalangia cameroni Perkins, Spalangia endius Walker, and Muscidifurax raptorellus Kogan and Legner to locate and attack stable fly hosts was evaluated under laboratory conditions. Postfeeding third-instar stable fly larvae were released and allowed to pupate in two arena types: large 4.8 liter chambers containing a field-collected, soiled equine bedding substrate; or 120-ml plastic cups containing wood chips. At the time of fly pupariation, parasitoids were released and permitted 72 h to locate and attack hosts. On average, parasitism rates of freely accessible stable fly pupae in cups were not significantly different between parasitoid species. However, parasitism rates in chambers containing either Spalangia spp. were ≈50-fold more than M. raptorellus. Additional intraspecies analysis revealed that parasitism rates both by S. cameroni and S. endius were not significantly different when pupae were freely accessible or within bedding, whereas M. raptorellus attacked significantly more pupae in cups than in the larger chambers where hosts were distributed within bedding. These results suggest that Spalangia spp. are more suited to successfully locate and attack hosts in habitats created by equine husbandry in Florida. Therefore, commercially available parasitoid mixtures containing Muscidifurax spp. may be ineffective if used as a control measure at Florida equine facilities.

  7. Thermal valorization of footwear leather wastes in bubbling fluidized bed combustion.

    PubMed

    Bahillo, A; Armesto, L; Cabanillas, A; Otero, J

    2004-01-01

    Transformation of hide (animal skins) into leather is a complicated process during which significant amounts of wastes are generated. Footwear is the sector that consumes the major part of leather (60%). Logically, this industry is producing the largest quantity of leather wastes. The objective of this work was to demonstrate the technical feasibility of fluidized bed technology to recover the energy from burning footwear leather wastes. Considering the characteristics of leather waste, especially the heating value (12.5-21 MJ/kg), it can be considered a fairly good fuel. Moreover, leather waste has suitable characteristics for combustion, e.g., high volatile matter (76.5%) and low ash content (5.2%). Two factors deserve special attention: N3O and NOx emissions as a consequence of its unusual high nitrogen content (14.1%) and the chromium speciation because chromium is the main element of ash (3.2%) due to its use in leather tanning. A series of experiments has been carried out in a 0.1 MWt bubbling fluidized bed pilot plant. The combustion efficiency, flue gas composition and chromium speciation were investigated. Despite having high nitrogen content, a low conversion rate of fuel-N to NOx and N2O was attained. Chromium was concentrated in the solid streams and it was consistently found as Cr(III+); no presence of Cr(VI+) was detected.

  8. Data summary of municipal solid waste management alternatives. Volume 5, Appendix C, Fluidized-bed combustion

    SciTech Connect

    1992-10-01

    This appendix provides information on fluidized-bed combustion (FBC) technology as it has been applied to municipal waste combustion (MWC). A review of the literature was conducted to determine: (1) to what extent FBC technology has been applied to MWC, in terms of number and size of units was well as technology configuration; (2) the operating history of facilities employing FBC technology; and (3) the cost of these facilities as compared to conventional MSW installations. Where available in the literature, data on operating and performance characteristics are presented. Tabular comparisons of facility operating/cost data and emissions data have been complied and are presented. The literature review shows that FBC technology shows considerable promise in terms of providing improvements over conventional technology in areas such as NOx and acid gas control, and ash leachability. In addition, the most likely configuration to be applied to the first large scale FBC dedicated to municipal solid waste (MSW) will employ circulating bed (CFB) technology. Projected capital costs for the Robbins, Illinois 1600 ton per day CFB-based waste-to-energy facility are competitive with conventional systems, in the range of $125,000 per ton per day of MSW receiving capacity.

  9. Second-generation pressurized fluidized bed combustion plants for electric power generation

    SciTech Connect

    Robertson, A. ); Bonk, D. ); Horazak, D. ); Newby, R. . Science and Technology Center); Rehmat, A.

    1992-01-01

    In the search for a more efficient, less costly, and more environmentally responsible method for generating electrical power from coal, research and development has turned to advanced pressurized fluidized bed combustion (PFBC) and coal gasification technologies. A logical extension of this work is the second-generation PFBC plant, which incorporates key components of each of these technologies. In this new type of plant, coal is devolatilized/carbonized before it is injected into the PFB combustor bed, and the low-Btu fuel gas produced by this process is burned in a gas turbine topping combustor. By integrating coal carbonization with PFB[degree]C (2300[degree]F) and higher can be achieved. When integrated with a conventional 16.5-MPa gage/538[degree]C/538[degree]C/8.5-kPa Hg (2400- psig/1000[degree]F/1000[degree]F/2.5-in. Hg) steam cycle, a plant electrical generating efficiency of 45-percent is predicted. Concomitant advantages, among others, are a 20-percent lower cost of electricity (compared with a conventional pulverized-coal-fired plant with stack gas scrubbing), reduced stack emissions, and components that can be shipped by barge. This paper presents a conceptual design and economic analysis of Pittsburgh No. 8 and Texas lignite coal-fired 500-MWe second-generation PFB combustion plants.

  10. Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion System

    SciTech Connect

    Wei-Ping Pan; Yan Cao; John Smith

    2008-05-31

    On February 14, 2002, President Bush announced the Clear Skies Initiative, a legislative proposal to control the emissions of nitrogen oxides (NO{sub x}), sulfur dioxide (SO{sub 2}), and mercury from power plants. In response to this initiative, the National Energy Technology Laboratory organized a Combustion Technology University Alliance and hosted a Solid Fuel Combustion Technology Alliance Workshop. The workshop identified multi-pollutant control; improved sorbents and catalysts; mercury monitoring and capture; and improved understanding of the underlying reaction chemistry occurring during combustion as the most pressing research needs related to controlling environmental emissions from fossil-fueled power plants. The Environmental Control Technology Laboratory will help meet these challenges and offer solutions for problems associated with emissions from fossil-fueled power plants. The goal of this project was to develop the capability and technology database needed to support municipal, regional, and national electric power generating facilities to improve the efficiency of operation and solve operational and environmental problems. In order to effectively provide the scientific data and the methodologies required to address these issues, the project included the following aspects: (1) Establishing an Environmental Control Technology Laboratory using a laboratory-scale, simulated fluidized-bed combustion (FBC) system; (2) Designing, constructing, and operating a bench-scale (0.6 MW{sub th}), circulating fluidized-bed combustion (CFBC) system as the main component of the Environmental Control Technology Laboratory; (3) Developing a combustion technology for co-firing municipal solid waste (MSW), agricultural waste, and refuse-derived fuel (RDF) with high sulfur coals; (4) Developing a control strategy for gaseous emissions, including NO{sub x}, SO{sub 2}, organic compounds, and heavy metals; and (5) Developing new mercury capturing sorbents and new

  11. Development of methods to predict agglomeration and deposition in fluidized-bed combustion systems (FBCS). Topical report

    SciTech Connect

    Mann, M.D.; Henderson, A.K.; Swanson, M.L.; Allan, S.E.

    1996-02-01

    The successful design and operation of advanced combustion systems require the ability to control and mitigate ash-related problems. The major ash-related problems are slag flow control, slag attack on the refractory, ash deposition on heat-transfer surfaces, corrosion and erosion of equipment materials, and emissions control. These problems are the result of physical and chemical interactions of the fuels, bed materials, and system components. The interactions that take place and ultimately control ash behavior in fluidized-bed combustion (FBC) systems are controlled by the abundance and association of the inorganic components in coal and by the system conditions. Because of the complexity of the materials and processes involved, the design and operations engineer often lacks the information needed to predict ash behavior and reduce ash-related problems. The deposition of ashes from the fluidized bed combustion of lignite and petroleum coke is described in this paper.

  12. Fluidized bed combustion of pelletized biomass and waste-derived fuels

    SciTech Connect

    Chirone, R.; Scala, F.; Solimene, R.; Salatino, P.; Urciuolo, M.

    2008-10-15

    The fluidized bed combustion of three pelletized biogenic fuels (sewage sludge, wood, and straw) has been investigated with a combination of experimental techniques. The fuels have been characterized from the standpoints of patterns and rates of fuel devolatilization and char burnout, extent of attrition and fragmentation, and their relevance to the fuel particle size distribution and the amount and size distribution of primary ash particles. Results highlight differences and similarities among the three fuels tested. The fuels were all characterized by limited primary fragmentation and relatively long devolatilization times, as compared with the time scale of particle dispersion away from the fuel feeding ports in practical FBC. Both features are favorable to effective lateral distribution of volatile matter across the combustor cross section. The three fuels exhibited distinctively different char conversion patterns. The high-ash pelletized sludge burned according to the shrinking core conversion pattern with negligible occurrence of secondary fragmentation. The low-ash pelletized wood burned according to the shrinking particle conversion pattern with extensive occurrence of secondary fragmentation. The medium-ash pelletized straw yielded char particles with a hollow structure, resembling big cenospheres, characterized by a coherent inorganic outer layer strong enough to prevent particle fragmentation. Inert bed particles were permanently attached to the hollow pellets as they were incorporated into ash melts. Carbon elutriation rates were very small for all the fuels tested. For pelletized sludge and straw, this was mostly due to the shielding effect of the coherent ash skeleton. For the wood pellet, carbon attrition was extensive, but was largely counterbalanced by effective afterburning due to the large intrinsic reactivity of attrited char fines. The impact of carbon attrition on combustion efficiency was negligible for all the fuels tested. The size

  13. A particulate model of solid waste incineration in a fluidized bed combining combustion and heavy metal vaporization

    SciTech Connect

    Mazza, G.; Falcoz, Q.; Gauthier, D.; Flamant, G.

    2009-11-15

    This study aims to develop a particulate model combining solid waste particle combustion and heavy metal vaporization from burning particles during MSW incineration in a fluidized bed. The original approach for this model combines an asymptotic combustion model for the carbonaceous solid combustion and a shrinking core model to describe the heavy metal vaporization. A parametric study is presented. The global metal vaporization process is strongly influenced by temperature. Internal mass transfer controls the metal vaporization rate at low temperatures. At high temperatures, the chemical reactions associated with particle combustion control the metal vaporization rate. A comparison between the simulation results and experimental data obtained with a laboratory-scale fluid bed incinerator and Cd-spiked particles shows that the heavy metal vaporization is correctly predicted by the model. The predictions are better at higher temperatures because of the temperature gradient inside the particle. Future development of the model will take this into account. (author)

  14. Mercury Adsorption and Oxidation over Cobalt Oxide Loaded Magnetospheres Catalyst from Fly Ash in Oxyfuel Combustion Flue Gas.

    PubMed

    Yang, Jianping; Zhao, Yongchun; Chang, Lin; Zhang, Junying; Zheng, Chuguang

    2015-07-07

    Cobalt oxide loaded magnetospheres catalyst from fly ash (Co-MF catalyst) showed good mercury removal capacity and recyclability under air combustion flue gas in our previous study. In this work, the Hg(0) removal behaviors as well as the involved reactions mechanism were investigated in oxyfuel combustion conditions. Further, the recyclability of Co-MF catalyst in oxyfuel combustion atmosphere was also evaluated. The results showed that the Hg(0) removal efficiency in oxyfuel combustion conditions was relative high compared to that in air combustion conditions. The presence of enriched CO2 (70%) in oxyfuel combustion atmosphere assisted the mercury oxidation due to the oxidation of function group of C-O formed from CO2. Under both atmospheres, the mercury removal efficiency decreased with the addition of SO2, NO, and H2O. However, the enriched CO2 in oxyfuel combustion atmosphere could somewhat weaken the inhibition of SO2, NO, and H2O. The multiple capture-regeneration cycles demonstrated that the Co-MF catalyst also present good regeneration performance in oxyfuel combustion atmosphere.

  15. Effect of coal combustion fly ash use in concrete on the mass transport release of constituents of potential concern.

    PubMed

    Garrabrants, Andrew C; Kosson, David S; DeLapp, Rossane; van der Sloot, Hans A

    2014-05-01

    Concerns about the environmental safety of coal combustion fly ash use as a supplemental cementitious material have necessitated comprehensive evaluation of the potential for leaching concrete materials containing fly ash used as a cement replacement. Using concrete formulations representative of US residential and commercial applications, test monoliths were made without fly ash replacement (i.e., controls) and with 20% or 45% of the portland cement fraction replaced by fly ash from four coal combustion sources. In addition, microconcrete materials were created with 45% fly ash replacement based on the commercial concrete formulation but with no coarse aggregate and an increased fine aggregate fraction to maintain aggregate-paste interfacial area. All materials were cured for 3 months prior to mass transport-based leach testing of constituents of potential concern (i.e., Sb, As, B, Ba, Cd, Cr, Mo, Pb, Se, Tl and V) according to EPA Method 1315. The cumulative release results were consistent with previously tested samples of concretes and mortars from international sources. Of the 11 constituents tested, only Sb, Ba, B, Cr and V were measured in quantifiable amounts. Microconcretes without coarse aggregate were determined to be conservative surrogates for concrete in leaching assessment since cumulative release from microconcretes were only slightly greater than the associated concrete materials. Relative to control materials without fly ash, concretes and microconcretes with fly ash replacement of cement had increased 28-d and 63-d cumulative release for a limited number 10 comparison cases: 2 cases for Sb, 7 cases for Ba and 1 case for Cr. The overall results suggest minimal leaching impact from fly ash use as a replacement for up to 45% of the cement fraction in typical US concrete formulations; however, scenario-specific assessment based on this leaching evaluation should be used to determine if potential environmental impacts exist.

  16. Effect of freeboard extension on co-combustion of coal and olive cake in a fluidized bed combustor.

    PubMed

    Akpulat, Onur; Varol, Murat; Atimtay, Aysel T

    2010-08-01

    In this study, flue gas emissions and combustion efficiencies during combustion and co-combustion of olive cake and coal were investigated in a bubbling fluidized bed. Temperature distributions along the combustion column and flue gas concentrations of O(2), CO, SO(2) and NO(x) were measured during combustion experiments. Two sets of experiments were performed to examine the effect of fuel composition, excess air ratio and freeboard extension on flue gas emissions and combustion efficiency. The results of the experiments showed that coal combustion occurs at lower parts of the combustion column whereas olive cake combustion takes place more in the freeboard region. As olive cake percentage in the fuel mixture increased, CO emissions increased, SO(2) and NO(x) emissions decreased. Additionally, flue gas emissions could be lowered with the freeboard extension while burning biomass or biomass/coal mixtures. Noticeable decrease in CO emissions and slight increase in combustion efficiencies were observed with a column height of 1900 mm instead of 900 mm.

  17. Some special features of combusting the coal-water fuel made of Belarussian brown coals in the fluidized bed

    NASA Astrophysics Data System (ADS)

    Borodulya, V. A.; Buchilko, E. K.; Vinogradov, L. M.

    2014-07-01

    This paper deals with the special features of combusting the coal-water fuel prepared on the basis of Belarussian brown coals and anthracite culm (Ukraine) in a fluidized bed. The sequence and the duration (calculated from the mathematical model being suggested) of the stages of the combustion of the coal-water fuel depending on the type of source solid fuel and fluidized bed temperature were experimentally confirmed. The temperature and time dependences of the content of sulfur, nitrogen, and carbon oxides in flue gases were studied.

  18. Design and construction of a circulating fluidized bed combustion facility for use in studying the thermal remediation of wastes

    NASA Astrophysics Data System (ADS)

    Rink, Karl K.; Kozinski, Janusz A.; Lighty, JoAnn S.; Lu, Quing

    1994-08-01

    Fluidized bed combustion systems have been widely applied in the combustion of solid fossil fuels, particularly by the power generation industry. Recently, attention has shifted from the conventional bubbling fluidized bed (BFB) to circulating fluidized bed (CFB) combustion systems. Inherent advantages of CFB combustion such as uniform temperatures, excellent mixing, high combustion efficiencies, and greater fuel flexibility have generated interest in the feasibility of CFB combustion systems applied to the thermal remediation of contaminated soils and sludges. Because it is often difficult to monitor and analyze the combustion phenomena that occurs within a full scale fluidized bed system, the need exists for smaller scale research facilities which permit detailed measurements of temperature, pressure, and chemical specie profiles. This article describes the design, construction, and operation of a pilot-scale fluidized bed facility developed to investigate the thermal remediation characteristics of contaminated soils and sludges. The refractory-lined reactor measures 8 m in height and has an external diameter of 0.6 m. The facility can be operated as a BFB or CFB using a variety of solid fuels including low calorific or high moisture content materials supplemented by natural gas introduced into the fluidized bed through auxiliary fuel injectors. Maximum firing rate of the fluidized bed is approximately 300 kW. Under normal operating conditions, internal wall temperatures are maintained between 1150 and 1350 K over superficial velocities ranging from 0.5 to 4 m/s. Contaminated material can be continuously fed into the fluidized bed or introduced as a single charge at three different locations. The facility is fully instrumented to allow time-resolved measurements of gaseous pollutant species, gas phase temperatures, and internal pressures. The facility has produced reproducible fluidization results which agree well with the work of other researchers. Minimum

  19. Test plan for valveless ash removal from pressurized fluid bed combustion systems

    SciTech Connect

    Hauserman, W.B.

    1989-07-01

    This is a test plan to demonstrate a method of ash removal from pressurized fluid bed combustion (PFBC) systems through small beds of crushed rock rather than conventional pressure let-down valves and lock hoppers. The economic advantage of such a method is that process-inherent erosive damage will be inflicted upon the cheaply replaceable crushed rock, rather than upon expensive, fabricated valve trim components. The concept to be tested is an extension of the gravel bucket'' principle in which an erosive, high pressure slurry stream passes through a bed of crushed rock with an adjustable flow path and cross-section. The original gravel bucket concept was inspired by the costly valve erosion problems projected for coal liquefaction plants. This project extends the same approach to systems where solids are to be removed from PFBC systems, with more limited possibilities of application to some coal gasification processes. If proven successful, a hot-gas gravel bucket could offer an economic alternative to a lock hopper plus a pair of expensive block valves. 6 refs., 10 figs., 1 tab.

  20. Pollutant emission characteristics of rice husk combustion in a vortexing fluidized bed incinerator.

    PubMed

    Duan, Feng; Chyang, Chiensong; Chin, Yucheng; Tso, Jim

    2013-02-01

    Rice husk with high volatile content was burned in a pilot scale vortexing fluidized bed incinerator. The fluidized bed incinerator was constructed of 6 mm stainless steel with 0.45 m in diameter and 5 m in height. The emission characteristics of CO, NO, and SO2 were studied. The effects of operating parameters, such as primary air flow rate, secondary air flow rate, and excess air ratio on the pollutant emissions were also investigated. The results show that a large proportion of combustion occurs at the bed surface and the freeboard zone. The SO2 concentration in the flue gas decreases with increasing excess air ratio, while the NOx concentration shows reverse trend. The flow rate of secondary air has a significant impact on the CO emission. For a fixed primary air flowrate, CO emission decreases with the secondary air flowrate. For a fixed excess air ratio, CO emission decreases with the ratio of secondary to primary air flow. The minimum CO emission of 72 ppm is attained at the operating condition of 40% excess air ratio and 0.6 partition air ratio. The NOx and SO2 concentrations in the flue gas at this condition are 159 and 36 ppm, which conform to the EPA regulation of Taiwan.

  1. Chemical looping combustion in a rotating bed reactor--finding optimal process conditions for prototype reactor.

    PubMed

    Håkonsen, Silje Fosse; Blom, Richard

    2011-11-15

    A lab-scale rotating bed reactor for chemical looping combustion has been designed, constructed, and tested using a CuO/Al(2)O(3) oxygen carrier and methane as fuel. Process parameters such as bed rotating frequency, gas flows, and reactor temperature have been varied to find optimal performance of the prototype reactor. Around 90% CH(4) conversion and >90% CO(2) capture efficiency based on converted methane have been obtained. Stable operation has been accomplished over several hours, and also--stable operation can be regained after intentionally running into unstable conditions. Relatively high gas velocities are used to avoid fully reduced oxygen carrier in part of the bed. Potential CO(2) purity obtained is in the range 30 to 65%--mostly due to air slippage from the air sector--which seems to be the major drawback of the prototype reactor design. Considering the prototype nature of the first version of the rotating reactor setup, it is believed that significant improvements can be made to further avoid gas mixing in future modified and up-scaled reactor versions.

  2. Evaluation of the behavior of Colombian coals during the combustion in fixed bed

    SciTech Connect

    Giraldo, M.; Chejne, F.; Hill, A.

    2000-07-01

    The improvements in the technological processes that have coal as energy source must be based on the knowledge of physical and chemical properties of coal and in the knowledge of its evolution during the combustion process. These characteristics are involved in the coal behavior. Moreover, the coal porosity has an important relevance on the reaction rate and in diverse physical and chemical properties, and therefore, is a key parameter in the usefulness of coal. This project includes studies about Colombian coal combustion and its kinetic behavior. The coal was characterized and classified by particle size,and origin. In this research project, the physical and chemical properties of coal that affect its applicability in different kinds of technological processes have been studied as well as the characteristics that could be related to pollutant generation. The study considers the following issues: the types and level of criteria pollutant precursor compounds such as sulfur and nitrogen in coal, the influence of particle size and porosity in the generation of pollutant species, the participation of pollutant species in the combustion process, and basic properties such as heat capacity, and heat effects related to the conversion of coal during heating test. Coal from Antioquia, Valle del Cauca and Cundinamarca Regions were used. These coals are used domestically by the industrial and power sector. Particle sizes of 4, 2.5 and 1 cm were used from each one of these coals. The combustion tests were done in a fixed bed pilot furnace. The amount of air used was controlled during the experiment. In addition, air and gas flow, concentration and temperatures were registered. This paper presents a description of: characteristics of each test, composition of generated gases, and the influence of the particle size and coal origin in the pollutant emissions, also includes the results of test done in different samples took along each test.

  3. Evaluation of the sulfur sorption properties of chemically improved limestones during fluidized-bed combustion

    SciTech Connect

    Grimm, U.

    1981-03-01

    A program was initiated in early 1980 at the Morgantown Energy Technology Center, Department of Energy, to evaluate the sulfur retention capability of a number of chemically improved limestones. These synthetic sorbents were developed by the University of Tennessee under an agreement with the Tennessee Valley Authority. Fredonia limestone and Shawnee hopper ash, in combination with a binder, are the main ingredients of the artificial sorbents. The manufacturing process of these pellets is described elsewhere. The effectiveness of the sorbents in sulfur emission controls and their calcium utilization potential were originally controlled by a rapid TG method displayed by the University of Tennessee. Performance data in real fluidizing combustion processes were missing. In a cooperative effort between the Morgantown Energy Technology Center and the Energy Research Division of TVA, an agreement was reached to test four new sorbents, a power station fly ash, and Fredonia limestone at the Morgantown 6-Inch Diameter AFBC Facility. The results generated in the fluidized-combustion test confirmed the findings by the University of Tennessee and the test program was determined to be highly successful. Details of the program as well as the results are presented in this report.

  4. Nitrogen oxides, sulfur trioxide, and mercury emissions during oxy-fuel fluidized bed combustion of Victorian brown coal.

    PubMed

    Roy, Bithi; Chen, Luguang; Bhattacharya, Sankar

    2014-12-16

    This study investigates, for the first time, the NOx, N2O, SO3, and Hg emissions from combustion of a Victorian brown coal in a 10 kWth fluidized bed unit under oxy-fuel combustion conditions. Compared to air combustion, lower NOx emissions and higher N2O formation were observed in the oxy-fuel atmosphere. These NOx reduction and N2O formations were further enhanced with steam in the combustion environment. The NOx concentration level in the flue gas was within the permissible limit in coal-fired power plants in Victoria. Therefore, an additional NOx removal system will not be required using this coal. In contrast, both SO3 and gaseous mercury concentrations were considerably higher under oxy-fuel combustion compared to that in the air combustion. Around 83% of total gaseous mercury released was Hg(0), with the rest emitted as Hg(2+). Therefore, to control harmful Hg(0), a mercury removal system may need to be considered to avoid corrosion in the boiler and CO2 separation units during the oxy-fuel fluidized-bed combustion using this coal.

  5. Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion System

    SciTech Connect

    Wei-Ping Pan; Songgeng Li

    2006-01-01

    This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period October 1, 2005 through December 31, 2005. Work was performed on the following activities. First, the fabrication and manufacture of the CFBC Facility is nearly completed. The erection of the CFBC facility is expected to start in the second week of February, 2006. Second, effect of flue gas components on mercury oxidation was investigated in a drop tube reactor. As a first step, experiment for mercury oxidation by chlorine was investigated. The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter is described in this report.

  6. Modified graphical autocatalytic set model of combustion process in circulating fluidized bed boiler

    NASA Astrophysics Data System (ADS)

    Yusof, Nurul Syazwani; Bakar, Sumarni Abu; Ismail, Razidah

    2014-07-01

    Circulating Fluidized Bed Boiler (CFB) is a device for generating steam by burning fossil fuels in a furnace operating under a special hydrodynamic condition. Autocatalytic Set has provided a graphical model of chemical reactions that occurred during combustion process in CFB. Eight important chemical substances known as species were represented as nodes and catalytic relationships between nodes are represented by the edges in the graph. In this paper, the model is extended and modified by considering other relevant chemical reactions that also exist during the process. Catalytic relationship among the species in the model is discussed. The result reveals that the modified model is able to gives more explanation of the relationship among the species during the process at initial time t.

  7. Fluidized-bed combustion process evaluation and program support. Annual report, October 1979-September 1980

    SciTech Connect

    Johnson, I.; Podolski, W.F.; Swift, W.M.; Carls, E.L.; Helt, J.E.; Henry, R.F.; Herzenberg, C.L.; Hanway, J.E.; Griggs, K.E.

    1981-03-01

    The purpose of this program is to support the pressurized fluidized-bed combustion project management team at Morgantown Energy Technology Center by providing a core group of experienced personnel (1) to prepare (a) program interaction plans suitable for recommending program needs and (b) recommendations for the DOE-PFBC development program, (2) to analyze data and designs for two large pilot-scale PFBC programs (i.e., Curtiss-Wright and IEA Grimethorpe), and (3) to participate in design/review for the large PFBC programs. Results are reported on a development methodology for the commercialization of PFBC technology, a FBC instrumentation state-of-the-art review, the development of a sodium sulfate dew point measurement instrument, and the evaluation of cyclones for hot gas cleanup.

  8. [Pulsed atmospheric fluidized bed combustion (PAFBC)]. Technical progress report, May--July 1988

    SciTech Connect

    Not Available

    1988-10-01

    This first Quarterly Technical Progress Report presents the results of work accomplished during the period April 19 through July 24,1988. The overall objective of the program is the development of a pulsed atmospheric fluidized-bed combustion (PAFBC) technology to burn coal and to provide heat and steam to commercial, institutional, and small industrial applications at a reasonable price in an environmentally acceptable manner. the program scope consisted of two tasks; the first was to establish preliminary feasibility by the use of theoretical and state-of-the-art information. This task was completed during the first quarter of the contract period and a topical report entitled, ``Pulsed Atmospheric Fluidized Bed combustion (PAFBC) - Preliminary Feasibility Study`` was prepared as a ``decision point to proceed`` deliverable in accordance with the terms of the contract. This first quarterly progress report therefore covers the contract activities subsequent to the approval of the feasibility study and the decision to proceed with the Task 2 effort. As the initial quarterly technical progress report, this document includes a subsection on background which will be omitted in subsequent reports. All effort during this period was devoted to the design and analysis of the PAFBC. Design drawings were prepared and fabrication and procurement initiated. Quotations were evaluated and a fabrication contract awarded. A site adjacent to the MTCI building was chosen for the installation of the PAFBC. Some ancillary components were purchased, renovated, and tested. Some delays in delivery of components have resulted in some schedule delay. It is anticipated that the program pace will accelerate as soon as parts are received and installation and assembly are initiated. 10 figs.,1 tab.

  9. Combustion of bark and wood waste in the fluidized bed boiler

    NASA Astrophysics Data System (ADS)

    Pleshanov, K. A.; Ionkin, I. L.; Roslyakov, P. V.; Maslov, R. S.; Ragutkin, A. V.; Kondrat'eva, O. E.

    2016-11-01

    In the Energy Development Strategy of Russia for the Period until 2035, special attention is paid to increased use of local fuel kinds—one of which is biofuel, in particular, bark and wood waste (BWW)— whose application at thermal power plants in Russia has been not developed due to the lack of appropriate technologies mastered by domestic energy mechanical engineering. The article describes the experience of BWW combustion in fluidized bed boilers installed on the energy objects of northern European countries. Based on this, reference points were defined (it is the section of boiler air-gas path where initially the approximate temperatures are set), making it possible to carry out a thermal design of a boiler and ensure its operation reliability. Permissible gas temperature at the furnace outlet at BWW combustion amounted to 950-1000°C. Exit gas temperature, depending on the implementation of special measures on protection of air heater from corrosion, amounted to 140-190°C. Recommended hot air temperature is within the range of 200-250°C. Recommendations for determining the boiler furnace dimensions are presented. Based on the presented reference temperatures in the main reference points, the thermal design of hot water boiler of KV-F-116-150 type with 116 MW capacity was carried out. The analysis of the results and comparison of designed boiler characteristics with operating energy boilers, in which a fuel is burned in a fluidized bed, were carried out. It is shown that, with increasing the boiler capacity, the ratio of its heating power Q to the crosssectional area of furnace chamber F rises. For power-generating boiler of thermal capacity of 100 MW, the ratio is within 1.8-2.2MW/m2. The boiler efficiency exceeds 90% in the range of changes of exit gas temperature typical for such equipment.

  10. Relationship between textural properties, fly ash carbons, and Hg capture in fly ashes derived from the combustion of anthracitic pulverized feed blends

    SciTech Connect

    Isabel Surez-Ruiz; Jose B. Parra

    2007-08-15

    In this work, the textural properties of a series of whole anthracitic-derived fly ashes sampled in eight hoppers from the electrostatic precipitators and their sized fractions (from {gt}150 to {lt}25 {mu}m) are investigated. Data from N{sub 2} adsorption isotherms at 77 K, helium density, and mercury porosimetry have contributed to establish a relationship between the Brunauer-Emmett-Teller (BET) surface areas, VTOT, porosity, carbon content (the type of fly ash carbons), and Hg retention in these fly ashes. The unburned carbons in these ashes are macroporous materials, and they are different from the carbons in fly ashes from classes C and F (the latter derived from the combustion of bituminous coals) and show different textural properties. These ashes represent the end member of the fly ash classes C and F with respect to certain textural properties. Although the BET surface area and VTOT values for the studied samples are the lowest reported, they increase with the increase in carbon content, anisotropic carbon content, and particle size of the ashes. Thus, a positive relationship between all these parameters and Hg capture by the coarser ash fractions was found. The finest fraction of carbons ({lt}25 {mu}m) represented an exception. Although it makes a significant contribution to the total carbon of the whole fly ashes and shows relatively higher surface areas and VTOT values, its Hg concentration was found to be the lowest. This suggests that the type of unburned carbons in the finest fraction and/or other adsorption mechanisms may play a role in Hg concentration. Because the textural properties of anisotropic carbons depend on their subtype and on their origin, the need for its differentiation has been evidenced. 54 refs., 8 figs., 3 tabs.

  11. Combustion tests of a turbine simulator burning low Btu fuel from a fixed bed gasifier

    SciTech Connect

    Cook, C.S.; Abuaf, N.; Feitelberg, A.S.; Hung, S.L.; Najewicz, D.J.; Samuels, M.S.

    1993-11-01

    One of the most efficient and environmentally compatible coal fueled power generation technologies is the integrated gasification combined cycle (IGCC) concept. Commercialization of the IGCC/HGCU concept requires successful development of combustion systems for high temperature low Btu fuel in gas turbines. Toward this goal, a turbine combustion system simulator has been designed, constructed, and fired with high temperature low Btu fuel. Fuel is supplied by a pilot scale fixed bed gasifier and hot gas desulfurization system. The primary objectives of this project are: (1) demonstration of long term operability of the turbine simulator with high temperature low Btu fuel; (2) measurement of NO{sub x}, CO, and particulate emissions; and (3) characterization of particulates in the fuel as well as deposits in the fuel nozzle, combustor, and first stage nozzle. In a related project, a reduced scale rich-quench-lean (RQL) gas turbine combustor has been designed, constructed, and fired with simulated low Btu fuel. The overall objective of this project is to develop an RQL combustor with lower conversion of fuel bound nitrogen (FBN) to NO{sub x} than a conventional combustor.

  12. Fuel-Nitrogen Evolution During Fluidized Bed Oxy-Coal Combustion

    NASA Astrophysics Data System (ADS)

    Sanchez, Astrid; Mondragon, Fanor; Eddings, Eric G.

    FTIR, thermo-gravimetric analysis techniques and molecular modelling were employed to study the effect of CO2 on fuel-nitrogen evolution under oxy-combustion conditions. The main objective is to compare NOx emissions at several molar fractions of O2 using Ar or CO2 as balance gas in a fluidized bed reactor. A char with about 16% N content was prepared by pyrolysis of polyacrylonitrile. This sample facilitated NOx evolution experiments due to the abundance of nitrogen complexes, and aided the identification and quantification of several N species by means ofFTIR. Results indicate that the presence of CO2 enhances NO2 formation. A complementary study was carried out by molecular modelling of the experimental reactions using the Gaussian 03 package. Different heterogeneous and homogeneous interactions between CO2 and char N-species were simulated. The results thus obtained show that the presence of CO2 during combustion can facilitate NCO formation which is a very reactive intermediate species that can be readily oxidized in the gaseous phase.

  13. Combustion of municipal solid wastes with oil shale in a circulating fluidized bed. Final report

    SciTech Connect

    1996-06-30

    The problem addressed by our invention is that of municipal solid waste utilization. The dimensions of the problem can be visualized by the common comparison that the average individual in America creates in five years time an amount of solid waste equivalent in weight to the Statue of Liberty. The combustible portion of the more than 11 billion tons of solid waste (including municipal solid waste) produced in the United States each year, if converted into useful energy, could provide 32 quads per year of badly needed domestic energy, or more than one-third of our annual energy consumption. Conversion efficiency and many other factors make such a production level unrealistic, but it is clear that we are dealing with a very significant potential resource. This report describes research pertaining to the co-combustion of oil shale with solid municipal wastes in a circulating fluidized bed. The oil shale adds significant fuel content and also constituents that can possible produce a useful cementitious ash.

  14. ESTABLISHMENT OF AN ENVIRONMENTAL CONTROL TECHNOLOGY LABORATORY WITH A CIRCULATING FLUIDIZED-BED COMBUSTION SYSTEM

    SciTech Connect

    Wei-Ping Pan; Kunlei Liu; John T. Riley

    2004-04-01

    The purpose of this report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the quarter January--March 2004. The following tasks have been completed. First, plans for the renovation of space for a new Combustion Laboratory for the CFBC Facility have progressed smoothly. Second, the design calculations, including the mass balances, energy balances, heat transfer, and strength calculations have been completed. Third, considerable modifications have been made on the draft design of the CFBC Facility based on discussions conducted during the project kick-off meeting held on January 13, 2004 at the National Energy Technology Laboratory (NETL). Comments received from various experts were also used to improve the design. Finally, the drawings of all assembly parts have been completed in order to develop specifications for the fabrication of individual parts. At the same time, the proposed work for the next quarter has been outlined in this report.

  15. Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion System

    SciTech Connect

    Wei-Ping Pan; Songgeng Li; John T. Riley

    2005-10-01

    This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period July 1, 2005 through September 30, 2005. The following tasks have been completed. First, the construction of the Circulating Fluidized-Bed (CFB) Combustor Building was completed. The experimental facilities have been moved into the CFB Combustor Building. Second, the fabrication and manufacture of the CFBC Facility is in the final stage and is expected to be completed before November 30, 2005. Third, the drop tube reactor has been remodeled and installed to meet the specific requirements for the investigation of the effects of flue gas composition on mercury oxidation. This study will start in the next quarter. Fourth, the effect of sulfur dioxide on molecular chlorine via the Deacon reaction was investigated. The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter is described in this report.

  16. Characteristics of high quality sorbent for fluidized bed combustion and problems of maintaining uniform reactivity

    SciTech Connect

    Bain, R.J. . Dept. of Geology)

    1993-03-01

    Fluidized bed combustion of coal is considered one of the more promising clean coal technologies for the future. While much research has gone into the design and operation of FBC units, there is little concern for what characterizes a high quality sorbent and the source of such a sorbent. Carbonate rocks, limestone and dolomite, have been tested extensively as sorbents and primarily two rock characteristics appear to significantly control reactivity: composition and texture. Calcium carbonate is more reactive than magnesium carbonate where all other rock characteristics are the same. In considering texture, highest reactivity is measured for carbonate rocks which consist of homogeneous, euhedral crystals ranging in size from .05 to .2 mm and which possess uniform intercrystalline porosity. The most reactive material possesses both high calcium content, uniform microcrystalline texture and intercrystalline porosity, however, such material is not very abundant in nature and is not locally available to midcontinent facilities. Sucrosic dolomite, which possesses uniform microcrystalline texture and intercrystalline porosity has high rank reactivity. While this rock is quite common, it occurs as beds, generally less than twenty feet thick, interlayered with less reactive dolomite types. Therefore, without selective quarrying methods, production of sorbent with uniformly high reactivity will be impossible.

  17. The Impact of Coal Combustion Fly Ash Used as a Supplemental Cementitious Material on the Leaching of Constituents from Cements and Concretes

    EPA Science Inventory

    The objective of this report is to compare the leaching of portland cement-based materials that have been prepared with and without coal combustion fly ash to illustrate whether there is evidence that the use of fly ash in cement and concrete products may result in increased leac...

  18. Emission characteristics of dioxins, furans and polycyclic aromatic hydrocarbons during fluidized-bed combustion of sewage sludge.

    PubMed

    Deng, Wenyi; Yan, Jianhua; Li, Xiaodong; Wang, Fei; Chi, Yong; Lu, Shengyong

    2009-01-01

    Pre-dried sewage sludge with high sulfur content was combusted in an electrically heated lab-scale fluidized-bed incinerator. The emission characteristics of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polycyclic aromatic hydrocarbons (PAHs) were studied. Coal and calcium oxide (CaO) were added during the sewage sludge combustion tests to optimize combustion conditions and control SO2 emission. The results indicated that the flue gases emitted during mono-combustion of sewage sludge were characterized by relatively high concentrations of SO2, NOx and organic pollutants, due to the high sulfur, nitrogen, and volatile matter content of sewage sludge. The total 16 USEPA priority PAHs and 2,3,7,8-substituted PCDD/Fs produced from sewage sludge combustion were found to be 106.14 microg/m3 and 8955.93 pg/m3 in the flue gas, respectively. In the case of co-combustion with coal (m(sludge)/m(coal) = 1:1), the 16 PAHs and 2,3,7,8-substituted PCDD/Fs concentrations were markedly lower than those found during mono-combustion of sewage sludge. During co-combustion, a suppressant effect of CaO on PCDD/Fs formation was observed.

  19. Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion System

    SciTech Connect

    Wei-Ping Pan; Yan Cao; John Smith

    2007-03-31

    This report is to present the progress made on the project entitled ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period January 1, 2007 through March 31, 2007. The effort in this quarter has concentrated on installing the CFBC Facility and for conducting cold fluidization operations tests in the CFBC facility. The assembly of the ash recirculation pipe duct from the cyclones back to the bed area of the combustor, including the upper and lower loop seals was completed. The electric bed pre-heater was installed to heat the fluidizing air as it enters the wind box. The induced draft fan along with its machine base and power supply was received and installed. The flue gas duct from secondary cyclone outlet to induced draft fan inlet was received and installed, as well as the induced fan flue gas discharge duct. Pressure testing from the forced draft fan to the outlet of the induced fan was completed. In related research a pilot-scale halogen addition test was conducted in the empty slipstream reactor (without (Selective Catalytic Reduction) SCR catalyst loading) and the SCR slipstream reactor with two commercial SCR catalysts. The greatest benefits of conducting slipstream tests can be flexible control and isolation of specific factors. This facility is currently used in full-scale utility and will be combined into 0.6MW CFBC in the future. This work attempts to first investigate performance of the SCR catalyst in the flue gas atmosphere when burning Powder River Basin (PRB), including the impact of PRB coal flue gas composition on the reduction of nitrogen oxides (NOx) and the oxidation of elemental mercury (Hg(0)) under SCR conditions. Secondly, the impacts of hydrogen halogens (Hydrogen fluoride (HF), Hydrogen chloride (HCl), Hydrogen Bromide (HBr) and Hydrogen Iodine (HI)) on Hg(0) oxidation and their mechanisms can be explored.

  20. Evaluation of fly ash from co-combustion of coal and petroleum coke for use in concrete

    SciTech Connect

    Scott, A.N.; Thomas, M.D.A.

    2007-01-15

    An investigation of fly ash (FA) produced from various blends of coal and petroleum coke (pet coke) fired at Belledune Generating Station, New Brunswick, Canada, was conducted to establish its performance relative to FA derived from coal-only combustion and its compliance with CSA A3000. The FA samples were beneficiated by an electrostatic separation process to produce samples for testing with a range of loss-on-ignition (LOI) values. The results of these studies indicate that the combustion of pet coke results in very little inorganic residue (for example, typically less than 0.5% ash) and the main impact on FA resulting from the co-combustion of coal and up to 25% pet coke is an increase in the unburned carbon content and LOI values. The testing of FA after beneficiation indicates that FA produced from fuels with up to 25% pet coke performs as good as FA produced from the same coal without pet coke.

  1. Characterisation of polycyclic aromatic hydrocarbons in flue gas and residues of a full scale fluidized bed combustor combusting non-hazardous industrial waste.

    PubMed

    Van Caneghem, J; Vandecasteele, C

    2014-11-01

    This paper studies the fate of PAHs in full scale incinerators by analysing the concentration of the 16 EPA-PAHs in both the input waste and all the outputs of a full scale Fluidized Bed Combustor (FBC). Of the analysed waste inputs i.e. Waste Water Treatment (WWT) sludge, Refuse Derived Fuel (RDF) and Automotive Shredder Residue (ASR), RDF and ASR were the main PAH sources, with phenanthrene, fluoranthene and pyrene being the most important PAHs. In the flue gas sampled at the stack, naphthalene was the only predominant PAH, indicating that the PAHs in FBC's combustion gas were newly formed and did not remain from the input waste. Of the other outputs, the boiler and fly ash contained no detectable levels of PAHs, whereas the flue gas cleaning residue contained only low concentrations of naphthalene, probably adsorbed from the flue gas. The PAH fingerprint of the bottom ash corresponded rather well to the PAH fingerprint of the RDF and ASR, indicating that the PAHs in this output, in contrast to the other outputs, were mainly remainders from the PAHs in the waste inputs. A PAH mass balance showed that the total PAH input/output ratio of the FBC ranged from about 100 to about 2600 depending on the waste input composition and the obtained combustion conditions. In all cases, the FBC was clearly a net PAH sink.

  2. Coal slurry solids/coal fluidized bed combustion by-product mixtures as plant growth media

    USGS Publications Warehouse

    Darmody, R.G.; Green, W.P.; Dreher, G.B.

    1998-01-01

    Fine-textured, pyritic waste produced by coal cleaning is stored in slurry settling ponds that eventually require reclamation. Conventionally, reclamation involves covering the dewatered coal slurry solids (CSS) with 1.3 m of soil to allow plant growth and prevent acid generation by pyrite oxidation. This study was conducted to determine the feasiblity of a less costly reclamation approach that would eliminate the soil cover and allow direct seeding of plants into amended CSS materials. Potential acidity of the CSS would be neutralized by additions of fluidized-bed combustion by-product (FBCB), an alkaline by-product of coal combustion. The experiment involved two sources of CSS and FBCB materials from Illinois. Birdsfoot trefoil (Lotus corniculatus L.), tall fescue (Festuca arundinacea Schreb.), and sweet clover (Melilotus officinalis (L.) Lam.) were seeded in the greenhouse into pots containing mixtures of the materials. CSS-1 had a high CaCO3:FeS2 ratio and needed no FBCB added to compensate for its potential acidity. CSS-2 was mixed with the FBCB materials to neutralize potential acidity (labeled Mix A and B). Initial pH was 5.6, 8.8, and 9.2 for the CSS-1, Mix A, and Mix B materials, respectively. At the end of the 70-day experiment, pH was 5.9 for all mixtures. Tall fescue and sweet clover grew well in all the treatments, but birdsfoot trefoil had poor emergence and survival. Elevated tissue levels of B, Cd, and Se were found in some plants. Salinity, low moisture holding capacity, and potentially phytotoxic B may limit the efficacy of this reclamation method.

  3. Combustion of liquid paint wastes in fluidized bed boiler as element of waste management system in the paint factory

    SciTech Connect

    Soko, W.A.; Biaecka, B.

    1998-12-31

    In this paper the solution to waste problems in the paint industry is presented by describing their combustion in a fluidized bed boiler as a part of the waste management system in the paint factory. Based on the Cleaner Production idea and concept of integration of design process with a future exploitation of equipment, some modifications of the waste management scheme in the factory are discussed to reduce the quantity of toxic wastes. To verify this concept combustion tests of paint production wastes and cocombustion of paint wastes with coal in an adopted industrial boiler were done. Results of these tests are presented in the paper.

  4. ON TRIMODAL PARTICLE SIZE DISTRIBUTIONS IN FLY ASH FROM PULVERIZED COAL COMBUSTION

    EPA Science Inventory

    Combustion generated fine particles, defined as those with aerodynamic diameters less than 2.5 micrometers, have come under increased regulatory scrutiny because of suspected links to adverse human health effects. Whereas classical theories regarding coal combustion suggest that ...

  5. Simulation of fluidized bed combustors. I - Combustion efficiency and temperature profile. [for coal-fired gas turbines

    NASA Technical Reports Server (NTRS)

    Horio, M.; Wen, C. Y.

    1976-01-01

    A chemical engineering analysis is made of fluidized-bed combustor (FBC) performance, with FBC models developed to aid estimation of combustion efficiency and axial temperature profiles. The FBC is intended for combustion of pulverized coal and a pressurized FBC version is intended for firing gas turbines by burning coal. Transport phenomena are analyzed at length: circulation, mixing models, drifting, bubble wake lift, heat transfer, division of the FB reactor into idealized mixing cells. Some disadvantages of a coal FBC are pointed out: erosion of immersed heat-transfer tubing, complex feed systems, carryover of unburned coal particles, high particulate emission in off-streams. The low-temperature bed (800-950 C) contains limestone, and flue-gas-entrained SO2 and NOx can be kept within acceptable limits.

  6. Market Assessment and Technical Feasibility Study of Pressurized Fluidized Bed Combustion Ash Use

    SciTech Connect

    Bland, A.E.; Brown, T.H.

    1996-12-31

    Western Research Institute in conjunction with the Electric Power Research Institute, Foster Wheeler Energy International, Inc. and the U.S. Department of Energy Technology Center (METC), has undertaken a research and demonstration program designed to examine the market potential and the technical feasibility of ash use options for pressurized fluidized bed combustion (PFBC) ashes. The assessment is designed to address six applications, including: (1) structural fill, (2) road base construction, (3) supplementary cementing materials in portland cement, (4) synthetic aggregate, and (5) agricultural/soil amendment applications. Ash from low-sulfur subbituminous coal-fired Foster Wheeler Energia Oy pilot circulating PFBC tests in Karhula, Finland, and ash from the high-sulfur bituminous coal-fired American Electric Power (AEP) bubbling PFBC in Brilliant, Ohio, were evaluated in laboratory and pilot-scale ash use testing. This paper addresses the technical feasibility of ash use options for PFBC unit using low- sulfur coal and limestone sorbent (karhula ash) and high-sulfur coal and dolomite sorbents (AEP Tidd ash).

  7. Land application uses of pressurized fluidized-bed combustion (PFBC) ash

    SciTech Connect

    Beeghly, J.H.; Dick, W.A.; Wolfe, W.

    1993-09-01

    Dry alkaline flue gas desulfurization by-products (dry lime and limestone FGD scrubber ashes) including the American Electric Power (AEP) Tidd PFBC bed and cyclone ash, are being evaluated for beneficial uses via land application for agriculture, mine reclamation, and soil stabilization in a 5 year study that began December, 1990. A 1989 Battelle Memorial Institute report had recommended that the highest priority in stimulating reuse of FGD by-products was the sponsoring of in-field research of coal combustion products generated from high sulfur midwestern coals to (a) better understand and quantify the leach rate, fate and transport of sulfates and trace metals and (b) demonstrate the level of protection necessary to build public acceptance of land-based reuses (1). The specific objectives of the demonstration project are as follows: To characterize the material generated from dry FGD processes; to demonstrate the utilization of dry FGD by-products as an soil amendment material on agricultural lands and on abandoned and active surface coal mines in Ohio; to demonstrate the use of dry FGD by-product as an engineering material for soil stabilization; to determine the quantities of dry FGD material than can be utilized in each of these applications; to determine the environmental and economic impact of utilizing the material.

  8. Synthesis of thermostable geopolymer from circulating fluidized bed combustion (CFBC) bottom ashes.

    PubMed

    Xu, Hui; Li, Qin; Shen, Lifeng; Wang, Wei; Zhai, Jianping

    2010-03-15

    Circulating fluidized bed combustion (CFBC) bottom ashes (CBAs) are a class of calcined aluminosilicate wastes with a unique thermal history. While landfill disposal of hazardous element-containing CBAs poses serious challenge, these wastes have long been neglected as source materials for geopolymer production. In this paper, geopolymerization of ground CBAs was investigated. Reactivity of the CBAs was analyzed by respective dissolution of the ashes in 2, 5, and 10N NaOH and KOH solutions. Geopolymer pastes were prepared by activating the CBAs by a series of alkalis hydroxides and/or sodium silicate solutions. Samples were cured at 40 degrees C for 168 h, giving a highest compressive strength of 52.9 MPa. Of the optimal specimen, characterization was conducted by TG-DTA, SEM, XRD, as well as FTIR analyses, and thermal stability was determined in terms of compressive strength evolution via exposure to 800 or 1050 degrees C followed by three cooling regimes, i.e. cooling in air, cooling in the furnace, and immerging in water. The results show that CBAs could serve as favorable source materials for thermostable geopolymers, which hold a promise to replace ordinary Portland cement (OPC) and organic polymers in a variety of applications, especially where fire hazards are of great concern.

  9. Feasibility of manufacturing geopolymer bricks using circulating fluidized bed combustion bottom ash.

    PubMed

    Chen, Chen; Li, Qin; Shen, Lifeng; Zhai, Jianping

    2012-06-01

    This paper presents a study on geopolymer bricks manufactured using bottom ash from circulating fluidized bed combustion (CFBC). The alkali activators used for synthesis were sodium silicate, sodium hydroxide, and potassium hydroxide and lithium hydroxide solutions. The study included the impact of alkali activator on compressive strength. The reaction products were analysed by XRD, FT-IR and SEM/EDS. The compressive strength of bricks was dependent on the modulus of the sodium silicate activator and the type and concentration of alkali activator. The highest compressive strength could be gained when the modulus was 1.5, and the value could reach 16.1 MPa (7 d after manufacture) and 21.9 MPa (28 d after manufacture). Under pure alkaline systems, the compressive strength was in the order of 10 M KOH > 10 M NaOH > 5 M LiOH > 5 M KOH > 5 M NaOH. Quartz was the only crystalline phase in the original bottom ash, and no new crystalline phase was found after the reaction. The main product of reaction was amorphous alkali aluminosilicate gel and a small amount of crystalline phase was also found by SEM.

  10. Combustion characteristics of paper mill sludge in a lab-scale combustor with internally cycloned circulating fluidized bed.

    PubMed

    Shin, D; Jang, S; Hwang, J

    2005-01-01

    After performing a series of batch type experiments using a lab-scale combustor, consideration was given to the use of an internally cycloned circulating fluidized bed combustor (ICCFBC) for a paper mill sludge. Operation parameters including water content, feeding mass of the sludge, and secondary air injection ratio were varied to understand their effects on combustion performance, which was examined in terms of carbon conversion rate (CCR) and the emission rates of CO, C(x)H(y) and NO(x). The combustion of paper mill sludge in the ICCFBC was compared to the reaction mechanisms of a conventional solid fuel combustion, characterized by kinetics limited reaction zone, diffusion limited reaction zone, and transition zone. The results of the parametric study showed that a 35% water content and 60 g feeding mass generated the best condition for combustion. Meanwhile, areal mass burning rate, which is an important design and operation parameter at an industrial scale plant, was estimated by a conceptual equation. The areal mass burning rate corresponding to the best combustion condition was approximately 400 kg/hm(2) for 35% water content. The secondary air injection generating swirling flow enhanced the mixing between the gas phase components as well as the solid phase components, and improved the combustion efficiency by increasing the carbon conversion rate and reducing pollutant emissions.

  11. Task 3.15 -- Impacts of low-NO{sub x} combustion on fly ash and slagging

    SciTech Connect

    Zygarlicke, C.J.; McCollor, D.P.

    1997-11-01

    This project by the Energy and Environmental Research Center (EERC) focuses on the issues of entrained-ash formation and slagging for low-NO{sub x} combustion systems in general. Time-resolved combustion tests under conventional and low-NO{sub x} conditions have been conducted to note particle-size formation and slagging deposition. Results will be used to support demonstration projects at the utility boiler scale. The results from this work are yielding an increased understanding of the mechanisms of ash formation during low-NO{sub x} combustion along with methods for enhancing heat transfer and fly ash collectibility. Specific objectives of this research project include (1) determining whether initial char and ash generated under low-NO{sub x} conditions have greater tendencies for slagging than conventionally generated ash and (2) determining the differences, if any, between particle size and composition for entrained ash generated under low-NO{sub x} and conventional combustion conditions. Progress on this sub-task is presented.

  12. Conventional pulverized coal and fluidized bed combustion testing of San Miguel lignite

    SciTech Connect

    Jones, M.L.; Goblirsch, G.M.

    1982-01-01

    The information generated at GFETC can be summarized in the following way: (1) The ash fouling furnace is an empirical tool which provides good information on relative fouling potential of various fuels. In the case of San Miguel lignite, tests suggest a severe fouling problem if conventional boiler designs are employed. (2) No effect in either deposition rate or deposit strength was seen when MgO and CaCO/sub 3/ were used as additives. For these tests a single addition rate was utilized at two different injection points in the system. (3) Deposits from the combustion of San Miguel lignite are very different from those observed when burning a Northern Great Plains lignite, primarily because of the building of deposits from the refractory wall. (4) No bed agglomeration was noted under the varied run conditions used in AFBC testing of this lignite fuel. (5) The AFBC NO/sub chi/ level emitted in the flue gas were always less than the NSPS limit of 0.6 lbs NO/sub 2//10/sup 6/ Btu. (6) Utilization of inherent alkali was less than that observed for North Dakota lignites. It was possible to meet NSPS standards of 90% sulfur capture using limestone addition. Use of lower grade fuels such as the lignite from the San Miguel mine is inevitable if we are to meet the expanding needs for energy in the United States today. To make use of these different fuels extensive testing on laboratory and pilot scales will be beneficial in avoiding major problems due to the different characteristics these materials possess. The present successful operation of a full scale boiler using the San Miguel lignite is a good example of the value pilot scale studies can have on the road to successful operation.

  13. Characterization of a fluidized-bed combustion ash to determine potential for environmental impact. Final report

    SciTech Connect

    Hassett, D.J.; Henderson, A.K.; Pflughoeft-Hassett, D.F.; Mann, M.D.; Eylands, K.E.

    1997-10-01

    A 440-megawatt, circulating fluidized-bed combustion (CFBC), lignite-fired power plant is planned for construction in Choctaw County north of Ackerman, Mississippi. This power plant will utilize Mississippi lignite from the first lignite mine in that state. Malcolm Pirnie, Inc., is working with the power plant developer in the current planning and permitting efforts for this proposed construction project. In order to accommodate Mississippi state regulatory agencies and meet appropriate permit requirements, Malcolm Pirnie needed to provide an indication of the characteristics of the by-products anticipated to be produced at the proposed plant. Since the Mississippi lignite is from a newly tapped mine and the CFBC technology is relatively new, Malcolm Pirnie contacted with the Energy and Environmental Research Center (EERC) to develop and perform a test plan for the production and characterization of ash similar to ash that will be eventually produced at the proposed power plant. The work performed at the EERC included two primary phases: production of by-products in a bench-scale CFBC unit using lignite provided by Malcolm Pirnie with test conditions delineated by Malcolm Pirnie to represent expected operating conditions for the full-scale plant; and an extensive characterization of the by-products produced, focusing on Mississippi regulatory requirements for leachability, with the understanding that return of the by-product to the mine site was an anticipated by-product management plan. The overall focus of this project was the environmental assessment of the by-product expected to be produced at the proposed power plant. Emphasis was placed on the leachability of potentially problematic trace elements in the by-products. The leaching research documented in this report was performed to determine trends of leachability of trace elements under leaching conditions appropriate for evaluating land disposal in monofills, such as returning the by-products to the mine

  14. Numerical and experimental studies on effects of moisture content on combustion characteristics of simulated municipal solid wastes in a fixed bed

    SciTech Connect

    Sun, Rui; Ismail, Tamer M.; Ren, Xiaohan; Abd El-Salam, M.

    2015-05-15

    Highlights: • The effects of moisture content on the burning process of MSW are investigated. • A two-dimensional mathematical model was built to simulate the combustion process. • Temperature distributions, process rates, gas species were measured and simulated. • The The conversion ratio of C/CO and N/NO in MSW are inverse to moisture content. - Abstract: In order to reveal the features of the combustion process in the porous bed of a waste incinerator, a two-dimensional unsteady state model and experimental study were employed to investigate the combustion process in a fixed bed of municipal solid waste (MSW) on the combustion process in a fixed bed reactor. Conservation equations of the waste bed were implemented to describe the incineration process. The gas phase turbulence was modeled using the k–ε turbulent model and the particle phase was modeled using the kinetic theory of granular flow. The rate of moisture evaporation, devolatilization rate, and char burnout was calculated according to the waste property characters. The simulation results were then compared with experimental data for different moisture content of MSW, which shows that the incineration process of waste in the fixed bed is reasonably simulated. The simulation results of solid temperature, gas species and process rate in the bed are accordant with experimental data. Due to the high moisture content of fuel, moisture evaporation consumes a vast amount of heat, and the evaporation takes up most of the combustion time (about 2/3 of the whole combustion process). The whole bed combustion process reduces greatly as MSW moisture content increases. The experimental and simulation results provide direction for design and optimization of the fixed bed of MSW.

  15. Performance improvement of a converted fluid bed boiler (from traveling grate type) for agro waste combustion -- A case study

    SciTech Connect

    Sethumadhavan, R.; Karthikeyan, G.; Raviprakash, A.V.; Vasudevan, R.

    1997-12-31

    This paper investigates the operational difficulty encountered while operating a fluid bed boiler--which was earlier serving with a traveling grate for agrowaste combustion. This boiler, although operating on fluid bed technology principle, could not produce required combustion efficiency while burning any of the agrowastes such as rice husk, de-oiled bran, ground nut shell, etc. While carrying out the performance assessment study, it was found that, this inefficient combustion was mainly due to the improper operating parameters and partly due to incorrect furnace configuration. The drawbacks of the system have been attended to and set right incurring a very minor expenditure. This has led to an annual fuel saving of approximately US $40,000. The major results achieved are: (1) boiler thermal efficiency increased from 66--73%; (2) boiler was loaded uniformly and on-time operation has increased to 100% from earlier 60%; (3) boiler shut down time due to operational problems has come down from 35 hours per month to 15 hours per month; (4) very effective dust collection system was achieved resulting in reduced ID fan erosion; and (5) an annual saving of US $100,000 (both direct and indirect) was achieved.

  16. Experimental investigation of wood combustion in a fixed bed with hot air

    SciTech Connect

    Markovic, Miladin Bramer, Eddy A.; Brem, Gerrit

    2014-01-15

    Highlights: • Upward combustion is a new combustion concept with ignition by hot primary air. • Upward combustion has three stages: short drying, rapid devolatilization and char combustion. • Variation of fuel moisture and inert content have little influence on the combustion. • Experimental comparison between conventional and upward combustion is presented. - Abstract: Waste combustion on a grate with energy recovery is an important pillar of municipal solid waste (MSW) management in the Netherlands. In MSW incinerators fresh waste stacked on a grate enters the combustion chamber, heats up by radiation from the flame above the layer and ignition occurs. Typically, the reaction zone starts at the top of the waste layer and propagates downwards, producing heat for drying and devolatilization of the fresh waste below it until the ignition front reaches the grate. The control of this process is mainly based on empiricism. MSW is a highly inhomogeneous fuel with continuous fluctuating moisture content, heating value and chemical composition. The resulting process fluctuations may cause process control difficulties, fouling and corrosion issues, extra maintenance, and unplanned stops. In the new concept the fuel layer is ignited by means of preheated air (T > 220 °C) from below without any external ignition source. As a result a combustion front will be formed close to the grate and will propagate upwards. That is why this approach is denoted by upward combustion. Experimental research has been carried out in a batch reactor with height of 4.55 m, an inner diameter of 200 mm and a fuel layer height up to 1 m. Due to a high quality two-layer insulation adiabatic conditions can be assumed. The primary air can be preheated up to 350 °C, and the secondary air is distributed via nozzles above the waste layer. During the experiments, temperatures along the height of the reactor, gas composition and total weight decrease are continuously monitored. The influence of

  17. Determination of the emissions of pollutants formed during the co-combustion of sludges with coals in a fluidized bed combustor

    SciTech Connect

    Gulyurtlu, I.; Lopes, H.; Bordalo, C.; Seica, A.; Cabrita, I.

    1996-12-31

    Co-combustion studies were carried out with mixtures of sludges with South African coal using a bubbling fluidized bed combustor of 90 kW. The combustion gases leaving the combustor was analyzed for CO{sub 2}, CO, O{sub 2}, NO{sub x}, N{sub 2}O, and SO{sub 2}. Sorbents were used to reduce the levels of SO{sub 2} and the influence of sorbent in capturing heavy metals during the combustion. Particles were collected from the combustion gases using an isokinetic sampling probe and the solids recovered were then analyzed to determine the particle size range and the composition.

  18. Mercury removal from coal combustion flue gas by modified fly ash.

    PubMed

    Xu, Wenqing; Wang, Hairui; Zhu, Tingyu; Kuang, Junyan; Jing, Pengfei

    2013-02-01

    Fly ash is a potential alternative to activated carbon for mercury adsorption. The effects of physicochemical properties on the mercury adsorption performance of three fly ash samples were investigated. X-ray fluorescence spectroscopy, X-ray photoelectron spectroscopy, and other methods were used to characterize the samples. Results indicate that mercury adsorption on fly ash is primarily physisorption and chemisorption. High specific surface areas and small pore diameters are beneficial to efficient mercury removal. Incompletely burned carbon is also an important factor for the improvement of mercury removal efficiency, in particular. The C-M bond, which is formed by the reaction of C and Ti, Si and other elements, may improve mercury oxidation. The samples modified with CuBr2, CuCl2 and FeCl3 showed excellent performance for Hg removal, because the chlorine in metal chlorides acts as an oxidant that promotes the conversion of elemental mercury (Hg0) into its oxidized form (Hg2+). Cu2+ and Fe3+ can also promote Hg0 oxidation as catalysts. HCl and O2 promote the adsorption of Hg by modified fly ash, whereas SO2 inhibits the Hg adsorption because of competitive adsorption for active sites. Fly ash samples modified with CuBr2, CuCl2 and FeCl3 are therefore promising materials for controlling mercury emissions.

  19. Discovery of a Rare Pterosaur Bone Bed in a Cretaceous Desert with Insights on Ontogeny and Behavior of Flying Reptiles

    PubMed Central

    Manzig, Paulo C.; Kellner, Alexander W. A.; Weinschütz, Luiz C.; Fragoso, Carlos E.; Vega, Cristina S.; Guimarães, Gilson B.; Godoy, Luiz C.; Liccardo, Antonio; Ricetti, João H. Z.; de Moura, Camila C.

    2014-01-01

    A pterosaur bone bed with at least 47 individuals (wing spans: 0.65–2.35 m) of a new species is reported from southern Brazil from an interdunal lake deposit of a Cretaceous desert, shedding new light on several biological aspects of those flying reptiles. The material represents a new pterosaur, Caiuajara dobruskii gen. et sp. nov., that is the southermost occurrence of the edentulous clade Tapejaridae (Tapejarinae, Pterodactyloidea) recovered so far. Caiuajara dobruskii differs from all other members of this clade in several cranial features, including the presence of a ventral sagittal bony expansion projected inside the nasoantorbital fenestra, which is formed by the premaxillae; and features of the lower jaw, like a marked rounded depression in the occlusal concavity of the dentary. Ontogenetic variation of Caiuajara dobruskii is mainly reflected in the size and inclination of the premaxillary crest, changing from small and inclined (∼115°) in juveniles to large and steep (∼90°) in adults. No particular ontogenetic features are observed in postcranial elements. The available information suggests that this species was gregarious, living in colonies, and most likely precocial, being able to fly at a very young age, which might have been a general trend for at least derived pterosaurs. PMID:25118592

  20. Discovery of a rare pterosaur bone bed in a cretaceous desert with insights on ontogeny and behavior of flying reptiles.

    PubMed

    Manzig, Paulo C; Kellner, Alexander W A; Weinschütz, Luiz C; Fragoso, Carlos E; Vega, Cristina S; Guimarães, Gilson B; Godoy, Luiz C; Liccardo, Antonio; Ricetti, João H Z; de Moura, Camila C

    2014-01-01

    A pterosaur bone bed with at least 47 individuals (wing spans: 0.65-2.35 m) of a new species is reported from southern Brazil from an interdunal lake deposit of a Cretaceous desert, shedding new light on several biological aspects of those flying reptiles. The material represents a new pterosaur, Caiuajara dobruskii gen. et sp. nov., that is the southermost occurrence of the edentulous clade Tapejaridae (Tapejarinae, Pterodactyloidea) recovered so far. Caiuajara dobruskii differs from all other members of this clade in several cranial features, including the presence of a ventral sagittal bony expansion projected inside the nasoantorbital fenestra, which is formed by the premaxillae; and features of the lower jaw, like a marked rounded depression in the occlusal concavity of the dentary. Ontogenetic variation of Caiuajara dobruskii is mainly reflected in the size and inclination of the premaxillary crest, changing from small and inclined (∼ 115°) in juveniles to large and steep (∼ 90°) in adults. No particular ontogenetic features are observed in postcranial elements. The available information suggests that this species was gregarious, living in colonies, and most likely precocial, being able to fly at a very young age, which might have been a general trend for at least derived pterosaurs.

  1. A circulating fluidized-bed furnace for combusting anthracite culm and the thermal-contact pyrolysis of coal

    NASA Astrophysics Data System (ADS)

    Rokhman, B. B.

    2007-09-01

    A method for thermal-contact pyrolysis of coal and a furnace design for combusting solid fuel in a circulating fluidized bed are proposed. The geometric, aerodynamic, and physicochemical parameters of the pyrolysis zone situated in the near-wall region of the freeboard space are calculated. It is shown that, if the initial fuel is fed through a part of the annular zone’s cross-sectional area, the near-wall clusters are destroyed and the concentration of the dispersed phase in the reaction zone increases, both resulting in the thermochemical processing of recirculating coke-ash particles to proceed more rapidly.

  2. Test results from the Department of Energy`s Pressurized Fluidized Bed Combustion Hot Gas Cleanup Program

    SciTech Connect

    Dennis, R.A.

    1995-12-01

    Presented here is a summary of operations and conclusions from the last two test campaigns of the Department of Energy`s Pressurized Fluidized Bed Combustion Hot Gas Cleanup Program which was implemented by the American Electric Power Service Corporation. In these tests, the Westinghouse Advanced Particle Filter (APF) operated on a one-seventh flow from the Tidd 70-MWe Pressurized Fluidized Bed Combustor. During these tests, the filter operated as predicted with extremely high particulate removal. During the combined test periods, more than 2,800 hours of operation were accumulated -- two operational periods lasted more than 650 hours. The completion of this program brings the total coal fired operating time of the APF to 5,854 hours.

  3. Results of the use of a system for continuous measurement of combustibles in the fly ash produced by burning of anthracite fines in a TPP-210A boiler

    SciTech Connect

    S.A. Fil; L.V. Golyshev; I.S. Mysak

    2002-11-15

    Data on the use of RCA-2000 (Mark & Vedell, Denmark) stationary analyzers of the content of combustibles in fly ash for optimizing the furnace performance of a TPP-210A boiler and determining the effect of process switchings of the boiler equipment on the quality of the furnace performance are presented.

  4. EFFECTS OF FLY ASH ON MERCURY OXIDATION DURING POST COMBUSTION CONDITIONS

    SciTech Connect

    Unknown

    2000-10-01

    Tests were performed in simulated flue gas streams using two fly ash samples from the electrostatic precipitators of two full-scale utility boilers. One fly ash was derived from a Powder River Basin (PRB) coal, while the other was derived from Blacksville coal (Pittsburgh No. 8 seam). The tests were performed at temperatures of 120 and 180 C under different gas compositions using whole fly ash samples as well as magnetic and nonmagnetic concentrates from sized fly ash. Only the Blacksville ash contained magnetic phases. The whole and fractionated fly ash samples were analyzed for morphology, chemical composition, mineralogical composition, total organic carbon, porosity, and surface area. Mineralogically, the Blacksville ash was composed predominantly of magnetite, hematite, quartz, and mullite, while the PRB ash contained mostly quartz with lesser amounts of lime, periclase, and calcium aluminum oxide. The iron oxides in the Blacksville ash were concentrated almost entirely in the largest size fraction. As anticipated, there was not a clean separation of magnetic (Fe-rich) and nonmagnetic (aluminosilicate-rich) phases for the Blacksville ash. The Blacksville ash had a significantly higher surface area and a much higher unburned carbon content than the PRB ash. Elemental mercury (Hg) streams were injected into the simulated flue gas and passed over filters (housed in a convection oven) loaded with fly ash. Concentrations of total, oxidized, and elemental Hg downstream from the ash samples were determined by the Ontario Hydro Method. The gas stream composition and whether or not ash was present in the gas stream were the two most important variables. Based on the statistical analyses, the presence of HCl, NO, NO{sub 2}, and SO{sub 2} and all two-way gas interactions were significant. In addition, it appears that even four-factor interactions between those gases are significant. The HCl, NO{sub 2}, and SO{sub 2} were critical gases resulting in Hg oxidation, while

  5. Volatiles combustion in fluidized beds. Technical progress report, 4 March 1993--3 June 1993

    SciTech Connect

    Hesketh, R.P.

    1993-09-01

    The goal of this project is to investigate the conditions in which volatiles will burn within both the dense and freeboard regions of fluidized beds. Experiments using a fluidized bed operated at incipient fluidization will be performed to characterize the effect of particle surface area, initial fuel concentration, and particle type on the inhibition of volatiles within a fluidized bed. The work conducted during the period 4 March, 1993 through 3 June, 1993 is reported in this technical progress report. The work during this time period consists primarily of the startup and trouble shooting of the fluidized bed reactor and gas phase modeling of methane and propane.

  6. Combustion and NO emission of high nitrogen content biomass in a pilot-scale vortexing fluidized bed combustor.

    PubMed

    Qian, F P; Chyang, C S; Huang, K S; Tso, Jim

    2011-01-01

    The combustion of biomass of various nitrogen contents and its NO emission were investigated experimentally in this study. All the experiments were conducted in an I.D. 0.45 m pilot-scale vortexing fluidized bed combustor (VFBC). Rice husk, corn, and soybean were used as feeding materials. Urea was added into the feeding materials for the purpose of adjusting nitrogen content. The effects of various operating parameters on NO emission, such as bed temperature, excess air ratio, and flow rate of secondary air, were investigated. The effects of nitrogen content of fuels on NO emissions were also investigated by using the mixtures of rice husk/soybean, rice husk/urea, corn/soybean, and corn/urea in various weight ratios. The NO concentrations at various positions in the combustor were sampled and recorded. The experimental results show that most nitric oxide is formed at just above the bed surface. Temperature and excess air ratio are the major operating parameters for NO emission. For biomass with high nitrogen content, NO emission decreases with excess air, and increases with bed temperature. Compared with char-N, volatile-N is the more dominant reactant source for NO emission.

  7. MERCURY SPECIATION IN COMBUSTION SYSTEMS: STUDIES WITH SIMULATED FLUE GASES AND MODEL FLY ASHES

    EPA Science Inventory

    The paper gives results of a bench-scale study of the effects of flue gas and fly ash parameters on the oxidation of elemental mercury in simulated flue gases containing hydrogen chloride (HCl), nitric oxide (NO), nitrogen dioxide (NO2), sulfur dioxide (SO2), and water vapor (H2O...

  8. Research on coal-water fuel combustion in a circulating fluidized bed / Badanie spalania zawiesinowych paliw węglowo-wodnych w cyrkulacyjnej warstwie fluidalnej

    NASA Astrophysics Data System (ADS)

    Kijo-Kleczkowska, Agnieszka

    2012-10-01

    In the paper the problem of heavily-watered fuel combustion has been undertaken as the requirements of qualitative coals combusted in power stations have been growing. Coal mines that want to fulfill expectations of power engineers have been forced to extend and modernize the coal enrichment plants. This causes growing quantity of waste materials that arise during the process of wet coal enrichment containing smaller and smaller under-grains. In this situation the idea of combustion of transported waste materials, for example in a hydraulic way to the nearby power stations appears attractive because of a possible elimination of the necessary deep dehydration and drying as well as because of elimination of the finest coal fraction loss arising during discharging of silted water from coal wet cleaning plants. The paper presents experimental research results, analyzing the process of combustion of coal-water suspension depending on the process conditions. Combustion of coal-water suspensions in fluidized beds meets very well the difficult conditions, which should be obtained to use the examined fuel efficiently and ecologically. The suitable construction of the research stand enables recognition of the mechanism of coal-water suspension contact with the inert material, that affects the fluidized bed. The form of this contact determines conditions of heat and mass exchange, which influence the course of a combustion process. The specificity of coal-water fuel combustion in a fluidized bed changes mechanism and kinetics of the process.

  9. Circulating fluidized bed combustion product addition to acid soil: alfalfa (Medicago sativa L.) composition and environmental quality.

    PubMed

    Chen, Liming; Dick, Warren A; Kost, David

    2006-06-28

    To reduce S emissions, petroleum coke with a high concentration of S was combusted with limestone in a circulating fluidized bed (CFB) boiler. The combustion process creates a bed product that has potential for agricultural uses. This CFB product is often alkaline and enriched in S and other essential plant nutrients, but also contains high concentrations of Ni and V. Agricultural land application of CFB product is encouraged, but little information is available related to plant responses and environmental impacts. CFB product and agricultural lime (ag-lime) were applied at rates of 0, 0.5, 1.0, and 2.0 times the soil's lime requirement (LR) to an acidic soil (Wooster silt loam). The 2.0x LR application rate of CFB product was equivalent to 67.2 Mg ha(-1). Alfalfa yield was increased 4.6 times by CFB product and 3.8 times by ag-lime compared to untreated control. Application of CFB product increased the concentration of V in soil and alfalfa tissue, but not in soil water, and increased the concentration of Ni in soil and soil water, but not in alfalfa tissue. However, these concentrations did not reach levels that might cause environmental problems.

  10. Investigation of the relationship between particulate-bound mercury and properties of fly ash in a full-scale 100 MWe pulverized coal combustion boiler

    SciTech Connect

    Sen Li; Chin-Min Cheng; Bobby Chen; Yan Cao; Jacob Vervynckt; Amanda Adebambo; Wei-Ping Pan

    2007-12-15

    The properties of fly ash in coal-fired boilers influence the emission of mercury from power plants into the environment. In this study, seven different bituminous coals were burned in a full-scale 100 MWe pulverized coal combustion boiler and the derived fly ash samples were collected from a mechanical hopper (MH) and an electrostatic precipitator hopper (ESP). The mercury content, specific surface area (SSA), unburned carbon, and elemental composition of the fly ash samples were analyzed to evaluate the correlation between the concentration of particulate-bound mercury and the properties of coal and fly ash. For a given coal, it was found that the mercury content in the fly ash collected from the ESP was greater than in the fly ash samples collected from the MHP. This phenomenon may be due to a lower temperature of flue gas at the ESP (about 135{sup o}C) compared to the temperature at the air preheater (about 350{sup o}C). Also, a significantly lower SSA observed in MH ash might also contribute to the observation. A comparison of the fly ash samples generated from seven different coals using statistical methods indicates that the mercury adsorbed on ESP fly ashes has a highly positive correlation with the unburned carbon content, manganese content, and SSA of the fly ash. Sulfur content in coal showed a significant negative correlation with the Hg adsorption. Manganese in fly ash is believed to participate in oxidizing volatile elemental mercury (Hg{sup 0}) to ionic mercury (Hg{sup 2+}). The oxidized mercury in flue gas can form a complex with the fly ash and then get removed before the flue gas leaves the stack of the boiler.

  11. Process costs and flowsheets, bed defluidization characteristics, stone reactivity changes and attrition losses for a regenerative fluidized-bed combustion process

    SciTech Connect

    Swift, W.M.; Montagna, J.C.; Smith, G.W.; Smyk, E.B.

    1980-05-01

    As a means of significantly reducing the amount of limestone required by the fluidized-bed combustion of coal, a limestone regeneration process has been developed which allows the sorbent to be recycled back to the combustor for reuse. To further the development of regeneration, experiments were performed to (1) evaluate the effects of repeated utilization on the sorbent reactivity for sulfation and regeneration and (2) characterize the minimum fluidizing-gas velocity required for the regeneration process to prevent agglomeration and defluidization of the bed. This report presents the results of those investigations plus (1) the development of process flowsheets and (2) an estimation of process costs and the economics of regeneration. The results of the experimental regeneration process studies confirm the potentially large reductions in the amount of sorbent required by FBC's which can be achieved by regeneration, possibly as high as 80%. The economic projections indicate that at current limestone prices, regeneration is not clearly justified on an economic basis; i.e., the cost of the regeneration process slightly exceeds the anticipated savings in limestone raw material cost which results from the regeneration process. However, the cost of limestone disposal has not been thoroughly addressed. Hence, if disposal costs due to environmental considerations, particularly the Resource Conservation and Recovery Act, become significant, the economic attractiveness of regeneration would be greatly enhanced.

  12. Separation of particulate from flue gas of fossil fuel combustion and gasification

    DOEpatents

    Yang, W.C.; Newby, R.A.; Lippert, T.E.

    1997-08-05

    The gas from combustion or gasification of fossil fuel contains fly ash and other particulates. The fly ash is separated from the gas in a plurality of standleg moving granular-bed filter modules. Each module includes a dipleg through which the bed media flows into the standleg. The bed media forms a first filter bed having an upper mass having a first frusto-conical surface in a frusto-conical member at the entrance to the standleg and a lower mass having a second frusto-conical surface of substantially greater area than the first surface after it passes through the standleg. A second filter media bed may be formed above the first filter media bed. The gas is fed tangentially into the module above the first surface. The fly ash is captured on the first frusto-conical surface and within the bed mass. The processed gas flows out through the second frusto-conical surface and then through the second filter bed, if present. The bed media is cleaned of the captured fly ash and recirculated to the moving granular bed filter. Alternatively, the bed media may be composed of the ash from the combustion which is pelletized to form agglomerates. The ash flows through the bed only once; it is not recycled. 11 figs.

  13. Mineralogy, chemical composition, and microstructure of ferrospheres in fly ashes from coal combustion

    SciTech Connect

    Yongchun Zhao; Junying Zhang; Junmin Sun; Xiangfei Bai; Chuguang Zheng

    2006-08-15

    Fourteen samples of coal and ferrospheres, which were recovered by dry magnetic separation from fly ashes, were collected from five power plants in China. The mineralogy, chemical composition, and microstructure of ferrospheres in fly ashes have been studied by optical microscopy, X-ray diffraction (XRD), Moessbauer spectroscopy, and field emission scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (FSEM-EDX). Iron in ferrospheres mainly occurs as Fe{sub 3}O{sub 4}, {alpha}Fe{sub 2}O{sub 3}, {gamma}Fe{sub 2}O{sub 3}, MgFe{sub 2}O{sub 4}, and Fe{sup 3+}-glass, ferrian spinel, and so on. On the basis of iron content, the ferrospheres in fly ashes are classified into four groups, namely ferrooxides, aluminosilicate-bearing ferrooxides, high-ferriferous aluminosilicates, and ferroaluminosilicates . Ferrooxides are derived from the oxidation of iron-bearing minerals, whereas aluminosilicate-bearing ferrooxides, high-ferriferous aluminosilicates, and ferroaluminosilicates are formed by the fusion of different proportions of inherent iron-bearing minerals and clay minerals. According to their microstructure, the ferrospheres in fly ashes are classified into seven groups, namely sheet ferrospheres, dendritic ferrospheres, granular ferrospheres, smooth ferrospheres, ferroplerospheres, porous ferrospheres, and molten drop ferrospheres. Sheet ferrospheres are derived from the oxidation of iron-bearing minerals immediately; smooth ferrospheres, molten drop ferrospheres, ferroplerospheres, and porous ferrospheres are the complex eutectic of inherent iron-bearing minerals and clay minerals; dendritic ferrospheres and granular ferrospheres are formed by the conglutination after the oxidation of iron-bearing minerals. Ferrooxides and aluminosilicate-bearing ferrooxides are important sources of the initial layer that occurs in deposits formed in coal-burning systems. 78 refs., 11 figs., 4 tabs.

  14. Modeling of fluidized-bed combustion of coal: Phase II, final reports. Volume II. Detailed description of the model

    SciTech Connect

    Louis, J.F.; Tung, S.E.

    1980-10-01

    This document is the second of a seven volume series of our Phase II Final Report. This volume deals with detailed descriptions of the structure of each program member (subroutines and functions), the interrelation between the members of a submodel, and the interrelation between the various submodels as such. The systems model for fluidized bed combustors (FBC-II) consists of a systematic combination of the following interrelated areas: fluid mechanics and bubble growth, char combustion and associated kinetics for particle burnout, sulfur capture, NO/sub x/ formation and reduction, freeboard reactions, and heat transfer. Program outline is shown in Figure 1.1. Input variables (supplied by the user are inspected to check that they lie inside the allowed range of values and are input to the various routines as needed. The necessary physical and fluid mechanical properties are calculated and utilized in estimating char combustion and sulfur capture in the bed and the freeboard. NO/sub x/ and CO emissions are estimated by taking into account all relevant chemical reactions. A material and energy balance is made over the bed. Figure 1.1 shows a block diagram of the systems program. In this diagram, the overall structure of the FBC program is illustrated in terms of the various submodels that together constitute the systems program. A more detailed outline of the systems program is shown in Figure 1.2. In this figure, all important subroutine members of the FBC program are shown, and their linkage to each other, as well as to the main program is indicated. A description of the exact sequence in which these various routines are called at time of program execution is provided in Chapter 8 under the executive routine MAIN.

  15. Experimental investigation of wood combustion in a fixed bed with hot air.

    PubMed

    Markovic, Miladin; Bramer, Eddy A; Brem, Gerrit

    2014-01-01

    Waste combustion on a grate with energy recovery is an important pillar of municipal solid waste (MSW) management in the Netherlands. In MSW incinerators fresh waste stacked on a grate enters the combustion chamber, heats up by radiation from the flame above the layer and ignition occurs. Typically, the reaction zone starts at the top of the waste layer and propagates downwards, producing heat for drying and devolatilization of the fresh waste below it until the ignition front reaches the grate. The control of this process is mainly based on empiricism. MSW is a highly inhomogeneous fuel with continuous fluctuating moisture content, heating value and chemical composition. The resulting process fluctuations may cause process control difficulties, fouling and corrosion issues, extra maintenance, and unplanned stops. In the new concept the fuel layer is ignited by means of preheated air (T>220 °C) from below without any external ignition source. As a result a combustion front will be formed close to the grate and will propagate upwards. That is why this approach is denoted by upward combustion. Experimental research has been carried out in a batch reactor with height of 4.55 m, an inner diameter of 200 mm and a fuel layer height up to 1m. Due to a high quality two-layer insulation adiabatic conditions can be assumed. The primary air can be preheated up to 350 °C, and the secondary air is distributed via nozzles above the waste layer. During the experiments, temperatures along the height of the reactor, gas composition and total weight decrease are continuously monitored. The influence of the primary air speed, fuel moisture and inert content on the combustion characteristics (ignition rate, combustion rate, ignition front speed and temperature of the reaction zone) is evaluated. The upward combustion concept decouples the drying, devolatilization and burnout phase. In this way the moisture and inert content of the waste have almost no influence on the combustion

  16. High-temperature-staged fluidized-bed combustion (HITS), bench scale experimental test program conducted during 1980. Final report

    SciTech Connect

    Anderson, R E; Jassowski, D M; Newton, R A; Rudnicki, M L

    1981-04-01

    An experimental program was conducted to evaluate the process feasibility of the first stage of the HITS two-stage coal combustion system. Tests were run in a small (12-in. ID) fluidized bed facility at the Energy Engineering Laboratory, Aerojet Energy Conversion Company, Sacramento, California. The first stage reactor was run with low (0.70%) and high (4.06%) sulfur coals with ash fusion temperatures of 2450/sup 0/ and 2220/sup 0/F, respectively. Limestone was used to scavenge the sulfur. The produced low-Btu gas was burned in a combustor. Bed temperature and inlet gas percent oxygen were varied in the course of testing. Key results are summarized as follows: the process was stable and readily controllable, and generated a free-flowing char product using coals with low (2220/sup 0/F) and high (2450/sup 0/F) ash fusion temperatures at bed temperatures of at least 1700/sup 0/ and 1800/sup 0/F, respectively; the gaseous product was found to have a total heating value of about 120 Btu/SCF at 1350/sup 0/F, and the practicality of cleaning the hot product gas and delivering it to the combustor was demonstrated; sulfur capture efficiencies above 80% were demonstrated for both low and high sulfur coals with a calcium/sulfur mole ratio of approximately two; gasification rates of about 5,000 SCF/ft/sup 2/-hr were obtained for coal input rates ranging from 40 to 135 lbm/hr, as required to maintain the desired bed temperatures; and the gaseous product yielded combustion temperatures in excess of 3000/sup 0/F when burned with preheated (900/sup 0/F) air. The above test results support the promise of the HITS system to provide a practical means of converting high sulfur coal to a clean gas for industrial applications. Sulfur capture, gas heating value, and gas production rate are all in the range required for an effective system. Planning is underway for additional testing of the system in the 12-in. fluid bed facility, including demonstration of the second stage char burnup

  17. Superadiabatic combustion of methane air mixtures under filtration in a packed bed

    SciTech Connect

    Zhdanok, S. . Chemical Physics Lab.); Kennedy, L.A.; Koester, G. . Dept. of Mechanical Engineering)

    1995-01-01

    Filtration combustion in porous media differs substantially from combustion in a homogeneous media. The difference is the heat transfer between the filtrated gas and the porous medium under conditions of active heat transfer over a highly developed internal solid surface. The reactive transfer is characterized by a thermal wave velocity that determines the velocity of heat accumulation in a porous medium due to the filtrated flow and by a reaction wave velocity. A resonance condition can occur when both velocities nearly coincide and the heat of reaction becomes localized in a moving thermal wave. A temperature can be reached much in excess of the adiabatic reaction temperature and thus self-propagating reactions are possible even in a weakly exothermic medium. The propagation of the localized resonance wave and the superadiabatic reaction effects is confirmed by experiments and the results of a simple mathematical analysis. The model is compared with predictions for the thermal and combustion wave speeds and demonstrates good agreement.

  18. Combustion of Biosolids in a Bubbling Fluidized Bed, Part 1: Main Ash-Forming Elements and Ash Distribution with a Focus on Phosphorus.

    PubMed

    Skoglund, Nils; Grimm, Alejandro; Ohman, Marcus; Boström, Dan

    2014-02-20

    This is the first in a series of three papers describing combustion of biosolids in a 5-kW bubbling fluidized bed, the ash chemistry, and possible application of the ash produced as a fertilizing agent. This part of the study aims to clarify whether the distribution of main ash forming elements from biosolids can be changed by modifying the fuel matrix, the crystalline compounds of which can be identified in the raw materials and what role the total composition may play for which compounds are formed during combustion. The biosolids were subjected to low-temperature ashing to investigate which crystalline compounds that were present in the raw materials. Combustion experiments of two different types of biosolids were conducted in a 5-kW benchscale bubbling fluidized bed at two different bed temperatures and with two different additives. The additives were chosen to investigate whether the addition of alkali (K2CO3) and alkaline-earth metal (CaCO3) would affect the speciation of phosphorus, so the molar ratios targeted in modified fuels were P:K = 1:1 and P:K:Ca = 1:1:1, respectively. After combustion the ash fractions were collected, the ash distribution was determined and the ash fractions were analyzed with regards to elemental composition (ICP-AES and SEM-EDS) and part of the bed ash was also analyzed qualitatively using XRD. There was no evidence of zeolites in the unmodified fuels, based on low-temperature ashing. During combustion, the biosolid pellets formed large bed ash particles, ash pellets, which contained most of the total ash content (54%-95% (w/w)). This ash fraction contained most of the phosphorus found in the ash and the only phosphate that was identified was a whitlockite, Ca9(K,Mg,Fe)(PO4)7, for all fuels and fuel mixtures. With the addition of potassium, cristobalite (SiO2) could no longer be identified via X-ray diffraction (XRD) in the bed ash particles and leucite (KAlSi2O6) was formed. Most of the alkaline-earth metals calcium and magnesium

  19. Combustion of Biosolids in a Bubbling Fluidized Bed, Part 1: Main Ash-Forming Elements and Ash Distribution with a Focus on Phosphorus

    PubMed Central

    2014-01-01

    This is the first in a series of three papers describing combustion of biosolids in a 5-kW bubbling fluidized bed, the ash chemistry, and possible application of the ash produced as a fertilizing agent. This part of the study aims to clarify whether the distribution of main ash forming elements from biosolids can be changed by modifying the fuel matrix, the crystalline compounds of which can be identified in the raw materials and what role the total composition may play for which compounds are formed during combustion. The biosolids were subjected to low-temperature ashing to investigate which crystalline compounds that were present in the raw materials. Combustion experiments of two different types of biosolids were conducted in a 5-kW benchscale bubbling fluidized bed at two different bed temperatures and with two different additives. The additives were chosen to investigate whether the addition of alkali (K2CO3) and alkaline-earth metal (CaCO3) would affect the speciation of phosphorus, so the molar ratios targeted in modified fuels were P:K = 1:1 and P:K:Ca = 1:1:1, respectively. After combustion the ash fractions were collected, the ash distribution was determined and the ash fractions were analyzed with regards to elemental composition (ICP-AES and SEM-EDS) and part of the bed ash was also analyzed qualitatively using XRD. There was no evidence of zeolites in the unmodified fuels, based on low-temperature ashing. During combustion, the biosolid pellets formed large bed ash particles, ash pellets, which contained most of the total ash content (54%–95% (w/w)). This ash fraction contained most of the phosphorus found in the ash and the only phosphate that was identified was a whitlockite, Ca9(K,Mg,Fe)(PO4)7, for all fuels and fuel mixtures. With the addition of potassium, cristobalite (SiO2) could no longer be identified via X-ray diffraction (XRD) in the bed ash particles and leucite (KAlSi2O6) was formed. Most of the alkaline-earth metals calcium and

  20. Hg and Se capture and fly ash carbons from combustion of complex pulverized feed blends mainly of anthracitic coal rank in Spanish power plants

    SciTech Connect

    I. Surez-Ruiz; J.C. Hower; G.A. Thomas

    2007-01-15

    In this work, the petrology and chemistry of fly ashes produced in a Spanish power plant from the combustion of complex pulverized feed blends made up of anthracitic/meta-anthracitic coals, petroleum, and natural coke are investigated. It was found that the behavior of fly ash carbons derived from anthracitic coals follows relatively similar patterns to those established for the carbons from the combustion of bituminous coals. Fly ashes were sampled in eight hoppers from two electrostatic precipitator (ESP) rows. The characterization of the raw ashes and their five sieved fractions (from {gt}150 to {lt}25 {mu}m) showed that glassy material, quartz, oxides, and spinels in different proportions are the main inorganic components. As for the organic fraction, the dominant fly ash carbons are anisotropic carbons, mainly unburned carbons derived from anthracitic vitrinite. The concentration of Se and Hg increased in ashes of the second ESP row, this increase being related to the higher proportion of anisotropic unburned carbons, particularly those largely derived from anthracitic vitrinite in the cooler ashes of the ESP (second row) and also related to the decrease in the flue gas temperature. This suggests that the flue gas temperature plays a major role in the concentration of mercury for similar ratios of unburned carbons. It was also found that Hg is highly concentrated in the medium-coarser fractions of the fly ashes ({gt} 45 {mu}m), there being a positive relationship between the amount of these carbons, which are apparently little modified during the combustion process, in the medium-coarse fractions of the ashes and the Hg retention. According to the results obtained, further research on this type of fly ash could be highly productive. 28 refs., 10 figs., 8 tabs.

  1. Task 3.15 -- Impacts of low-NOx combustion on fly ash and slagging. Semi-annual report, July 1--December 31, 1996

    SciTech Connect

    Zygarlicke, C.J.; McCollor, D.P.

    1997-08-01

    With the advent of the Clean Air Act Amendments of 1990, the coal-fired power industry began a more accelerated move toward using low-NOx burner (LNB) technologies to reduce NOx emissions. Most LNBs incorporate less oxygen with the coal initially, creating a cooler and somewhat substoichiometric initial combustion zone, with additional oxygen added further on in the combustion process to complete char combustion. Another method used to achieve lower NOx emissions is to fire the coal substoichiometrically and add additional air through overfire air ports. Both of these methods create certain impacts on fireside performance that are different from conventional high-excess-air firing arrangements. Some of the impacts that have been noticed by the utility industry are higher levels of unburned carbon in the fly ash and bottom ash, increased boiler tube corrosion, higher particulate loadings on control devices, and changes in slagging in the main furnace. Work on the fundamental mechanisms of entrained ash and ash deposit formation during low-NOx combustion has been sparse. This project by the Energy and Environmental Research Center (EERC) focuses on the issues of entrained ash formation and slagging for low-NOx combustion systems in general. Time-resolved combustion tests under conventional and low-NOx conditions have been conducted to note particle-size formation and slagging deposition. The results from this work are yielding an increased understanding of the mechanisms of ash formation during low-NOx combustion along with methods for enhancing heat transfer and fly ash collectability. Specific objectives of this research project include (1) determining whether initial char and ash generated under low-NOx conditions have greater tendencies for slagging than conventionally generated ash and (2) determining the differences, if any, between particle size and composition for entrained ash generated under low-NOx and conventional combustion conditions.

  2. Investigation of the flow in the vortex chamber with centrifugal fluidizing bed with and without combustion

    NASA Astrophysics Data System (ADS)

    Volchkov, E. P.; Dvornikov, N. A.; Lukashov, V. V.; Abdrakhmanov, R. Kh.

    2013-12-01

    The flow in the vortex chamber with centrifugal fluidized bed of solid particles was studied experimentally and simulated numerically. The chambers of different configurations were considered, and this allowed us to change the ratio of centrifugal and gravity forces. To estimate the hydraulic losses in the vortex chamber, a simple model was suggested.

  3. Investigation of the flow in the vortex chamber with centrifugal fluidizing bed with and without combustion

    NASA Astrophysics Data System (ADS)

    Volchkov, E. P.; Dvornikov, N. A.; Lukashov, V. V.; Abdrakhmanov, R. Kh.

    2014-12-01

    The flow in the vortex chamber with centrifugal fluidized bed of solid particles was studied experimentally and simulated numerically. The chambers of different configurations were considered, and this allowed us to change the ratio of centrifugal and gravity forces. To estimate the hydraulic losses in the vortex chamber, a simple model was suggested.

  4. Limited effect of fly-wheel and spinal mobilization exercise countermeasures on lumbar spine deconditioning during 90 d bed-rest in the Toulouse LTBR study

    NASA Astrophysics Data System (ADS)

    Belavý, Daniel L.; Ohshima, Hiroshi; Bareille, Marie-Pierre; Rittweger, Jörn; Felsenberg, Dieter

    2011-09-01

    We examined the effect of high-load fly-wheel (targeting the lower-limb musculature and concurrent loading of the spine via shoulder restraints) and spinal movement countermeasures against lumbar spine muscle atrophy, disc and spinal morphology changes and trunk isokinetic torque loss during prolonged bed-rest. Twenty-four male subjects underwent 90 d head-down tilt bed-rest and performed either fly-wheel (FW) exercises every three days, spinal movement exercises in lying five times daily (SpMob), or no exercise (Ctrl). There was no significant impact of countermeasures on losses of isokinetic trunk flexion/extension ( p≥0.65). Muscle volume change by day-89 of bed-rest in the psoas, iliacus, lumbar erector spinae, lumbar multifidus and quadratus lumborum, as measured via magnetic resonance imaging (MRI), was statistically similar in all three groups ( p≥0.33). No significant effect on MRI-measures of lumbar intervertebral disc volume, spinal length and lordosis ( p≥0.09) were seen either, but there was some impact ( p≤0.048) on axial plane disc dimensions (greater reduction than in Ctrl) and disc height (greater increases than in Ctrl). MRI-data from subjects measured 13 and 90-days after bed-rest showed partial recovery of the spinal extensor musculature by day-13 after bed-rest with this process complete by day-90. Some changes in lumbar spine and disc morphology parameters were still persistent 90-days after bed-rest. The present results indicate that the countermeasures tested were not optimal to maintain integrity of the spine and trunk musculature during bed rest.

  5. DISPOSAL OF FLUIDIZED BED COMBUSTION ASH IN AN UNDERGROUND MINE TO CONTROL ACID MINE DRAINAGE AND SUBSIDENCE

    SciTech Connect

    Unknown

    2000-01-01

    This project will evaluate the technical, economic and environmental feasibility of filling abandoned underground mine voids with alkaline, advanced coal combustion wastes (Fluidized Bed Combustion-FBC ash). Success will be measured in terms of technical feasibility of the approach (i.e. % void filling), cost, environmental benefits (acid mine drainage and subsidence control) and environmental impacts (noxious ion release). This document reports on progress made during Phase III. The report is divided into three major sections. The first deals with the Hydraulic Injection component. This section of the report describes the progress and milestones associated with the grouting activities of the project. The Phase III tasks of Economic Analysis and Regulatory Analysis is covered under this section. The second component is Pneumatic Injection. This section reports on progress made towards completing the demonstration project. The last component involves evaluating the migration of contaminants through the grouted mine. A computer model has been developed in earlier phases and will model the flow of water in and around the grouted Longridge mine.

  6. DISPOSAL OF FLUIDIZED BED COMBUSTION ASH IN AN UNDERGROUND MINE TO CONTROL ACID MINE DRAINAGE AND SUBSIDENCE

    SciTech Connect

    Unknown

    1999-07-01

    This project will evaluate the technical, economic and environmental feasibility of filling abandoned underground mine voids with alkaline, advanced coal combustion wastes (Fluidized Bed Combustion-FBC ash). Success will be measured in terms of technical feasibility of the approach (i.e. % void filling), cost, environmental benefits (acid mine drainage and subsidence control) and environmental impacts (noxious ion release). This document reports on progress made during Phase III. The report is divided into three major sections. The first deals with the Hydraulic Injection component. This section of the report describes the progress and milestones associated with the grouting activities of the project. The Phase III tasks of Economic Analysis and Regulatory Analysis is covered under this section. The second component is Pneumatic Injection. This section reports on progress made towards completing the demonstration project. The last component involves evaluating the migration of contaminants through the grouted mine. A computer model has been developed in earlier phases and will model the flow of water in and around the grouted Longridge mine.

  7. DISPOSAL OF FLUIDIZED BED COMBUSTION ASH IN AN UNDERGROUND MINE TO CONTROL ACID MINE DRAINAGE AND SUBSIDENCE

    SciTech Connect

    Unknown

    2000-04-01

    This project will evaluate the technical, economic and environmental feasibility of filling abandoned underground mine voids with alkaline, advanced coal combustion wastes (Fluidized Bed Combustion-FBC ash). Success will be measured in terms of technical feasibility of the approach (i.e. % void filling), cost, environmental benefits (acid mine drainage and subsidence control) and environmental impacts (noxious ion release). This document reports on progress made during Phase III. The report is divided into three major sections. The first deals with the Hydraulic Injection component. This section of the report describes the progress and milestones associated with the grouting activities of the project. The Phase III tasks of Economic Analysis and Regulatory Analysis is covered under this section. The second component is Pneumatic Injection. This section reports on progress made towards completing the demonstration project. The last component involves evaluating the migration of contaminants through the grouted mine. A computer model has been developed in earlier phases and will model the flow of water in and around the grouted Longridge mine.

  8. DISPOSAL OF FLUIDIZED BED COMBUSTION ASH IN AN UNDERGROUND MINE TO CONTROL ACID MINE DRAINAGE AND SUBSIDENCE

    SciTech Connect

    Unknown

    1999-04-01

    This project will evaluate the technical, economic and environmental feasibility of filling abandoned underground mine voids with alkaline, advanced coal combustion wastes (Fluidized Bed Combustion-FBC ash). Success will be measured in terms of technical feasibility of the approach (i.e. % void filling), cost, environmental benefits (acid mine drainage and subsidence control) and environmental impacts (noxious ion release). This document reports on progress made during Phase III. The report is divided into three major sections. The first deals with the Hydraulic Injection component. This section of the report describes the progress and milestones associated with the grouting activities of the project. The Phase III tasks of Economic Analysis and Regulatory Analysis is covered under this section. The second component is Pneumatic Injection. This section reports on progress made towards completing the demonstration project. The last component involves evaluating the migration of contaminants through the grouted mine. A computer model has been developed in earlier phases and will model the flow of water in and around the grouted Longridge mine.

  9. DISPOSAL OF FLUIDIZED BED COMBUSTION ASH IN AN UNDERGROUND MINE TO CONTROL ACID MINE DRAINAGE AND SUBSIDENCE

    SciTech Connect

    Unknown

    1999-01-01

    This project will evaluate the technical, economic and environmental feasibility of filling abandoned underground mine voids with alkaline, advanced coal combustion wastes (Fluidized Bed Combustion-FBC ash). Success will be measured in terms of technical feasibility of the approach (i.e. % void filling), cost, environmental benefits (acid mine drainage and subsidence control) and environmental impacts (noxious ion release). This document reports on progress made during Phase III. The report is divided into four major sections. The first deals with the Hydraulic Injection component. This section of the report reports on progress and milestones associated with the grouting activities of the project. The Phase III tasks of Economic Analysis and Regulatory Analysis is covered under this section. The second component is Pneumatic Injection. This section reports on progress made towards completing the demonstration project. The Water Quality component involves background monitoring of water quality and precipitation at the Phase III (Longridge) mine site. The last component involves evaluating the migration of contaminants through the grouted mine. A computer model has been developed in earlier phases and will model the flow of water in and around the grouted Longridge mine.

  10. Nitrogen evolution during the co-combustion of hydrothermally treated municipal solid waste and coal in a bubbling fluidized bed.

    PubMed

    Lu, Liang; Jin, Yuqi; Liu, Hongmei; Ma, Xiaojun; Yoshikawa, Kunio

    2014-01-01

    Nitrogen evolution was studied during the co-combustion of hydrothermally treated municipal solid wastes (HT MSW) and coal in a bubbling fluidized bed (BFB). HT MSW blending ratios as 10%, 20% and 30% (wt.%) were selected and tested at 700, 800, 900 °C. Emissions of NO and N2O from blends were measured and compared with the results of mono-combustion trials. Moreover, concentrations of precursors like NH3 and HCN were also quantified. The results are summarized as follows: NO emissions were predominant in all the cases, which rose with increasing temperature. The blending of HT MSW contributed to the NO reduction. N2O emissions decreased with temperature rising and the blending of HT MSW also presented positive effects. At 30% HT MSW addition, both NO and N2O emissions showed the lowest values (391.85 ppm and 55.33 ppm, respectively at 900 °C). For the precursors, more HCN was detected than NH3 and both played important roles on the gas side nitrogen evolution.

  11. Effect of CaO on retention of S, Cl, Br, As, Mn, V, Cr, Ni, Cu, Zn, W and Pb in bottom ashes from fluidized-bed coal combustion power station.

    PubMed

    Bartoňová, Lucie; Klika, Zdeněk

    2014-07-01

    This work was conducted to evaluate whether Ca-bearing additives used during coal combustion can also help with the retention of some other elements. This work was focused on the evaluation of bottom ashes collected during four full-scale combustion tests at an operating thermal fluidized-bed power station. Bottom ashes were preferred to fly ashes for the study to avoid interference from condensation processes usually occurring in the post-combustion zone. This work focused on the behaviors of S, Cl, Br, As, Mn, V, Cr, Ni, Cu, Zn, W, and Pb. Strong positive correlations with CaO content in bottom ashes were observed (for all four combustion tests) for S, As, Cl and Br (R=0.917-0.999). Strong inverse proportionality was calculated between the contents of Pb, Zn, Ni, Cr and Mn and CaO, so these elements showed association to materials other than Ca-bearing compounds (e.g., to aluminosilicates, organic matter, etc.). Somewhat unclear behaviors were observed for W, Cu, and V. Their correlation coefficients were evaluated as statistically "not significant", i.e., these elements were not thought to be significantly associated with CaO. It was also discovered that major enrichment of CaO in the finest bottom ash fractions could be advantageously used for simple separation of elements strongly associated with these fractions, mainly S and As, but also Cl or Br. Removal of 5% of the finest ash particles brings about a decrease in As concentration down to 77%-80% of its original bulk ash content, which can be conveniently used e.g., when high As content complicates further ash utilization.

  12. Regenerable cobalt oxide loaded magnetosphere catalyst from fly ash for mercury removal in coal combustion flue gas.

    PubMed

    Yang, Jianping; Zhao, Yongchun; Zhang, Junying; Zheng, Chuguang

    2014-12-16

    To remove Hg(0) in coal combustion flue gas and eliminate secondary mercury pollution of the spent catalyst, a new regenerable magnetic catalyst based on cobalt oxide loaded magnetospheres from fly ash (Co-MF) was developed. The catalyst, with an optimal loading of 5.8% cobalt species, attained approximately 95% Hg(0) removal efficiency at 150 °C under simulated flue gas atmosphere. O2 could enhance the Hg(0) removal activity of magnetospheres catalyst via the Mars-Maessen mechanism. SO2 displayed an inhibitive effect on Hg(0) removal capacity. NO with lower concentration could promote the Hg(0) removal efficiency. However, when increasing the NO concentration to 300 ppm, a slightly inhibitive effect of NO was observed. In the presence of 10 ppm of HCl, greater than 95.5% Hg(0) removal efficiency was attained, which was attributed to the formation of active chlorine species on the surface. H2O presented a seriously inhibitive effect on Hg(0) removal efficiency. Repeated oxidation-regeneration cycles demonstrated that the spent Co-MF catalyst could be regenerated effectively via thermally treated at 400 °C for 2 h.

  13. Building ceramics with an addition of pulverized combustion fly ash from the thermal power plant Nováky

    NASA Astrophysics Data System (ADS)

    Húlan, Tomáš; Trník, Anton; Medved, Igor; Štubňa, Igor; Kaljuvee, Tiit

    2016-07-01

    Pulverized combustion fly ash (PFA) from the Power plant Nováky (Slovakia) is analyzed for its potential use in the production of building ceramics. Three materials are used to prepare the mixtures: illite-rich clay (IRC), PFA and IRC fired at 1000 °C (called grog). The mixtures contain 60 % of IRC and 40 % of a non-plastic compound (grog or PFA). A various amount of the grog is replaced by PFA and the effect of this substitution is studied. Thermal analyses (TGA, DTA, thermodilatometry, and dynamical thermomechanical analysis) are used to analyze the processes occurring during firing. The flexural strength and thermal conductivity are determined at room temperature after firing in the temperature interval from 800 to 1100 °C. The results show that an addition of PFA slightly decreases the flexural strength. The thermal conductivity and porosity are practically unaffected by the presence of PFA. Thus, PFA from the Power plant Nováky is a convenient non-plastic component for manufacturing building ceramics.

  14. A model of coal particle drying in fluidized bed combustion reactor

    SciTech Connect

    Komatina, M.; Manovic, V.; Saljnikov, A.

    2007-02-15

    Experimental and theoretical investigation on drying of a single coal particle in fluidized bed combustor is presented. Coal particle drying was considered via the moist shrinking core mechanism. The results of the drying test runs of low-rank Serbian coals were used for experimental verification of the model. The temperature of the coal particle center was measured, assuming that drying was completed when the temperature equalled 100{sup o}C. The influence of different parameters (thermal conductivity and specific heat capacity of coal, fluidized bed temperature, moisture content and superheating of steam) on drying time and temperature profile within the coal particle was analyzed by a parametric analysis. The experimentally obtained results confirmed that the moist shrinking core mechanism can be applied for the mathematical description of a coal particle drying, while dependence between drying time and coal particle radius, a square law relationship, implicates heat transfer control of the process and confirms the validity of assumptions used in modeling.

  15. Valveless ash removal from pressurized fluidized-bed combustion systems by gravel bucket

    SciTech Connect

    Henderson, A.K.; Hauserman, W.B.

    1991-03-01

    The objective of this project is to apply the gravel bucket pressure letdown concept to a stream of hot, gas-borne ash, under conditions similar to those found in a pressurized fluidized-bed combustor, where the system pressure is dissipated across a packed or partially fluidized bed of coarsely crushed rock. A second objective is to use the data collected during testing to develop a mathematical model which can be used to predict pressure drop in a gravel bucket device. The final objective of the project is to develop an economic analysis comparing the cost of constructing and operating a gravel bucket with that of a lockhopper system. The results of this analysis will be submitted as a separate report. 9 refs., 6 figs., 5 tabs.

  16. An Overview of Atmospheric Fluidized Bed Combustion Systems as Applied to Army Scale Central Heat Plants

    DTIC Science & Technology

    1992-11-01

    However, not every boiler SJ. Makasi and R, Schwieger . 14 is suitable for AFBC retrofitting. Much depends on the site and age of the boiler. Sonic...Recommended limits of coal sizing for conventional boilers. (R. Schwieger , "lndusinal Boilers-What’s Happening Today," Power, February 1977 and February...2069 (DOE, December 1985), Makasi, J., and R. Schwieger , "Fluidized-Bed Boilers," Power (May 1987). Malone. R.A. and Veatch Engineers-Architects

  17. Temperatures of coal particle during devolatilization in fluidized bed combustion reactor

    SciTech Connect

    Komatina, M.; Manovic, V.; Saljnikov, A.

    2006-11-15

    The purpose of this study was to investigate the thermal behavior of coal during devolatilization in fluidized bed. Temperatures in the center of single coal particle were measured by thermocouple. Two coals were tested (brown coal Bogovina and lignite Kosovo), using dry coal particle, shaped into spherical form of diameters 7 and 10 mm, in temperature range from 300 to 850{sup o}C. Unsteady behavior of coal particle during heating and devolatilization in fluidized bed was described by a model that takes into account heat transfer between bed and particle surface, heat transfer through particle and an endothermic chemical reaction of first-order. Based on the mathematical model analysis and compared with experimental results, values of heat conductivity {lambda}{sub C} and heat capacity (C-p) of coal were determined. The best agreement was obtained for constant thermal properties, for brown coal {lambda}{sub C} = 0.20 W/mK and C{sub p} = 1200 J/kgK and for lignite {lambda}{sub C} = 0.17 W/mK and C-p = 1100 J/kgK.

  18. INVESTIGATION OF HEAT TRANSFER AND COMBUSTION IN THE ADVANCED FLUIDIZED BED COMBUSTOR (FBC)

    SciTech Connect

    Dr. Seong W. Lee

    1998-04-01

    This technical report summarizes the research conducted and progress achieved during the period from January 1, 1998 to March 31, 1998. The systematic combustion tests were conducted to investigate the thermal performance and heat transfer effect of the exploratory hot model. The different ratios of the top to the bottom secondary air flow rate were chosen to study the effect of the secondary air flow rate. The test results indicated that the secondary air flow rate was a very sensitive factor to the combustion temperature profile. The heat transfer coefficients were changed along the combustor height. Numerical simulation was continued to determine the pressure profiles and temperature profiles in the hot combustor model. The pressure change at the bottom is greater than that of the top region because of a large amount of primary air input. The higher pressure zone is formed where the secondary air flows into the center region of the combustor. The high temperature zone of the bottom section is located at the fuel injector nozzle outlet. The lower temperature profiles were near the combustor wall because the cooling effect of the heat exchanger. The center temperature of the combustor at the upper secondary air nozzles is higher than that at the lower secondary air nozzles.

  19. Characterizing and modeling combustion of mild-gasification chars in pressurized fluidized beds

    SciTech Connect

    Daw, C.S.

    1993-03-01

    Performance estimates for the UCC2, IGTP1, and IGTP2 chars were made for a typical utility PFBC boiler having nominal characteristics similar to those of the American Electric Power 75 MW(e) Tidd PFBC demonstration facility. Table 2 summarizes the assumed boiler operating conditions input to the PFBC simulation code. Input fuel parameters for the chars and reference fuels were determined from their standard ASTM analyses (Table 1) and the results of the bench-scale characterization tests at B&W`s Alliance Research Center. The required characterization information for the reference fuels was available from the B&W data base, and the combustion reactivity information for the mild-gasification chars was generated in the pressurized bench-scale reactor as described earlier. Note that the combustion reactivity parameters for Beulah lignite are those previously measured at low-pressure conditions. It was necessary to use the previous values as the new parameters could not be accurately measured in the pressurized bench-scale facility. Based on very limited measurements of particle size attrition in paste-type feed systems, it was assumed that all of the fuels (including the chars) would have a very small (essentially negligible) degree of attrition in the feed system. Char devolatilization parameters were assumed to be equal to those of anthracite because of the very low levels of volatiles present in UCC2, IGTP1, and IGTP2. Major fuel input parameters and higher heating values are summarized in Table 3.

  20. Characterizing and modeling combustion of mild-gasification chars in pressurized fluidized beds

    SciTech Connect

    Daw, C.S.

    1993-01-01

    Performance estimates for the UCC2, IGTP1, and IGTP2 chars were made for a typical utility PFBC boiler having nominal characteristics similar to those of the American Electric Power 75 MW(e) Tidd PFBC demonstration facility. Table 2 summarizes the assumed boiler operating conditions input to the PFBC simulation code. Input fuel parameters for the chars and reference fuels were determined from their standard ASTM analyses (Table 1) and the results of the bench-scale characterization tests at B W's Alliance Research Center. The required characterization information for the reference fuels was available from the B W data base, and the combustion reactivity information for the mild-gasification chars was generated in the pressurized bench-scale reactor as described earlier. Note that the combustion reactivity parameters for Beulah lignite are those previously measured at low-pressure conditions. It was necessary to use the previous values as the new parameters could not be accurately measured in the pressurized bench-scale facility. Based on very limited measurements of particle size attrition in paste-type feed systems, it was assumed that all of the fuels (including the chars) would have a very small (essentially negligible) degree of attrition in the feed system. Char devolatilization parameters were assumed to be equal to those of anthracite because of the very low levels of volatiles present in UCC2, IGTP1, and IGTP2. Major fuel input parameters and higher heating values are summarized in Table 3.

  1. Combustion

    NASA Technical Reports Server (NTRS)

    Bulzan, Dan

    2007-01-01

    An overview of the emissions related research being conducted as part of the Fundamental Aeronautics Subsonics Fixed Wing Project is presented. The overview includes project metrics, milestones, and descriptions of major research areas. The overview also includes information on some of the emissions research being conducted under NASA Research Announcements. Objective: Development of comprehensive detailed and reduced kinetic mechanisms of jet fuels for chemically-reacting flow modeling. Scientific Challenges: 1) Developing experimental facilities capable of handling higher hydrocarbons and providing benchmark combustion data. 2) Determining and understanding ignition and combustion characteristics, such as laminar flame speeds, extinction stretch rates, and autoignition delays, of jet fuels and hydrocarbons relevant to jet surrogates. 3) Developing comprehensive kinetic models for jet fuels.

  2. Modeling of fluidized-bed combustion of coal: Phase II, final reports. Volume 1. Model evolution and development

    SciTech Connect

    Louis, J.F.; Tung, S.E.

    1980-10-01

    The Energy Laboratory of the Massachusetts Institute of Technology (M.I.T.), under Department of Energy (DOE) sponsorship, has been engaged in the development of a comprehensive mechanistic model of Fluidized Bed Combustors (FBC). The primary aims of this modeling effort are the generation and to the extent possible, validation of an analytical framework for the design and scale-up of fluidized bed combustors. In parallel with this modeling effort, M.I.T. also embarked upon the development of an FBC-Data Base Management System (FBC-DBMS) aimed at facilitating the coordination, interpretation and utilization of the experimental data that are or will become available from diverse sources, as well as in the identification of areas of large uncertainty or having a paucity of experimental results. The synergistic operation of the FBC-Model and FBC-Data Base promises to offer a powerful tool for the design and optimization of FBC's and represents the ultimate goal of the M.I.T. effort. The modeling effort was initially focused upon evaluation and application of state-of-the-art models. The initial system model was divided into five basic components: fluid dynamics, combustion, sulfur capture, heat transfer and emissions. Due to the technical complexity of modeling FBC operation and the initial primitive nature of models for these components, it was deemed necessary to be able to incorporate evolutionary improvements in understanding and correlating FBC phenomena: the M.I.T. system model is, therefore, modular in nature, i.e., each sub-model can be replaced by an updated or equivalent sub-model without necessitating reprogramming of the entire system model.

  3. The use of fluidized bed combuster ash in the solidification of high oil and grease sediments

    SciTech Connect

    Bennett, R.G.; Stine, E.F. Jr.

    1996-12-31

    It has been common practice at petroleum refineries to dispose of oil sludges (containing oil, grease solids and water) in onsite pits. Remediation of these pits has typically involved in-situ solidification of the sludges using mixtures of Portland cement and fly ash. While this leaves the oily material in place, the resulting form is less permeable than the resulting sludge and has significant strength to support a cap. The supported cap reduces the infiltration rate of water to contact the solidified sludges. Due to the cumulative impact of the solidification and capping process the mobility of these materials is therefore reduced. Since 1991 an oil refinery has been investigating the closure of several large storm water impoundment ponds. These ponds contain sediments that are high in oil and grease and mostly low in solids. Oil and grease content ranges from 1.5 to 20% by EPA Method 9071. Consistencies and liquid content of the sediments vary from a very wet free flowing emulsion to a congealed sludge with about 70% solids. The primary concern of closure was to solidify the residues while still maintaining the low leachability and mobility of both metals and volatile organic hydrocarbons (VOCs).

  4. MARKET ASSESSMENT AND TECHNICAL FEASIBILITY STUDY OF PRESSURIZED FLUIDIZED BED COMBUSTION ASH USE

    SciTech Connect

    A.E. Bland; T.H. Brown

    1997-04-01

    Western Research Institute, in conjunction with the Electric Power Research Institute, Foster Wheeler International, Inc. and the US Department of Energy, has undertaken a research and demonstration program designed to examine the market potential and the technical feasibility of ash use options for PFBC ashes. Ashes from the Foster Wheeler Energia Oy pilot-scale circulating PFBC tests in Karhula, Finland, combusting (1) low-sulfur subbituminous and (2) high-sulfur bituminous coal, and ash from the AEP's high-sulfur bituminous coal-fired bubbling PFBC in Brilliant, Ohio, were evaluated in laboratory and pilot-scale ash use testing at WR1. The technical feasibility study examined the use of PFBC ash in construction-related applications, including its use as a cementing material in concrete and use in cement manufacturing, fill and embankment materials, soil stabilization agent, and use in synthetic aggregate production. Testing was also conducted to determine the technical feasibility of PFBC ash as a soil amendment for acidic and sodic problem soils and spoils encountered in agricultural and reclamation applications. The results of the technical feasibility testing indicated the following conclusions. PFBC ash does not meet the chemical requirements as a pozzolan for cement replacement. However, it does appear that potential may exist for its use in cement production as a pozzolan and/or as a set retardant. PFBC ash shows relatively high strength development, low expansion, and low permeability properties that make its use in fills and embankments promising. Testing has also indicated that PFBC ash, when mixed with low amounts of lime, develops high strengths, suitable for soil stabilization applications and synthetic aggregate production. Synthetic aggregate produced from PFBC ash is capable of meeting ASTM/AASHTO specifications for many construction applications. The residual calcium carbonate and calcium sulfate in the PFE3C ash has been shown to be of value in

  5. Application of noncatalytic gas-solid reactions for a single pellet of changing size to the modeling of fluidized-bed combustion of coal char containing sulfur

    SciTech Connect

    Rehmat, A.; Saxena, S.C.; Land, R.H.

    1980-09-01

    A mechanistic model is developed for coal char combustion, with sulfur retention by limestone or dolomite sorbent, in a gas fluidized bed employing noncatalytic single pellet gas-solid reactions. The shrinking core model is employed to describe the kinetics of chemical reactions taking place on a single pellet; changes in pellet size as the reaction proceeds are considered. The solids are assumed to be in back-mix condition whereas the gas flow is regarded to be in plug flow. Most char combustion occurs near the gas distributor plate (at the bottom of the bed), where the bubbles are small and consequently the mass transfer rate is high. For such a case, the analysis is considerably simplified by ignoring the bubble phase since it plays an insignificant role in the overall rate of carbon conversion. Bubble-free operation is also encounterd in the turbulent regime, where the gas flow is quite high and classical bubbles do not exist. Formulation of the model includes setting up heat and mass balance equations pertaining to a single particle (1) exposed to a varying reactant concentration along the height of the bed and (2) whose size changes during reaction. These equations are then solved numerically to account for particles of all sizes in the bed in obtaining the overall carbon conversion efficiency and resultant sulfur retention. In particular, the influence on sorbent requirement of several fluid-bed variables such as oxygen concentration profile, particle size, reaction rate for sulfation reaction, and suflur adsorption efficiency are examined.

  6. The Ability of selected Pupal Parasitoids (Hymenoptera: Pteromalidae) to Locate Stable Fly Hosts in a Soiled Equine Bedding Substrate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Laboratory evaluations assessing the ability of Spalangia cameroni Perkins, Spalangia endius Walker, and Muscidifurax raptorellus Kogan and Legner to locate and attack stable fly hosts in a field-collected fly-breeding substrate suggest that Spalangia spp. are more suited to successfully locate and ...

  7. Investigation of heat transfer and combustion in the advanced fluidized bed combustor (FBC)

    SciTech Connect

    Lee, S.W.

    1999-09-01

    This technical report summarizes the research conducted and progress achieved during the period from April 1, 1998 to June 30, 1998. The numerical simulation was continued to determine the concentration distribution of the gas species, heat flux and heat transfer coefficients in the hot combustor model. The different gas concentration profiles showed the gas mixing characteristics along the combustor height. The center zone of the combustor has a relatively high methane mass concentration. The injection of secondary air squeezes the uprising flue gas and methane that causes the fuel-lean zone near the secondary air nozzles. The carbon dioxide concentration increased with the increasing of the combustor height. The peak concentration of oxygen remains at the combustor wall because of the secondary injection. The heat flux on the wall of the upper chamber is much higher than that of the lower chamber. It is believed that the heat flux is affected by the designed strong swirl and secondary air injection. The heat transfer coefficient changes along the combustor height were also affected by the multiple secondary air injection. The numerical simulation results could verify the predictions of the experimental results. It is a quite similar trend of the heat transfer coefficient changes based on the combustion test results.

  8. Engineering systems analysis of pressurized fluidized-bed-combustion power systems

    SciTech Connect

    Graves, R.L.; Griffin, F.P.; Lackey, M.E.

    1982-04-01

    This effort was conducted to provde supporting data for the research and development program on pressurized fluidized bed combustor (PFBC) systems being continued under the auspices of the Office of Coal Utilization of DOE. This report deals with the first phase of the effort, designated Task 1, which was scoped to be a somewhat broad review of PFBC technology and an analysis to determine its potential and sensitivity to key development needs. Background information pertaining to the application of PFBC to the market for coal-fired technology is included. The status of development is reviewed and the deficiencies in data are identified. Responses to a survey of PFBC developers are reviewed with emphasis on the high risk areas of the PFBC concept. Some of these problems are: uncertainty of life of gas turbine components; lack of demonstration of load following; and hot solids handling. Some high risk areas, such as the gas cleanup or gas turbine systems, can be relieved by reducing the severity of design conditions such as the turbine inlet temperature. Alternate turbine designs or plant configurations are also possible solutions. Analyses were performed to determine whether the advantages held by PFBC systems in cost, efficiency, and emissions would be nullified by measures taken to reduce risk. In general, the results showed that the attractive features of the PFBC could be preserved.

  9. Development of Methane and Nitrous Oxide Emission Factors for the Biomass Fired Circulating Fluidized Bed Combustion Power Plant

    PubMed Central

    Cho, Chang-Sang; Sa, Jae-Hwan; Lim, Ki-Kyo; Youk, Tae-Mi; Kim, Seung-Jin; Lee, Seul-Ki; Jeon, Eui-Chan

    2012-01-01

    This study makes use of this distinction to analyze the exhaust gas concentration and fuel of the circulating fluidized bed (CFB) boiler that mainly uses wood biomass, and to develop the emission factors of Methane (CH4), Nitrous oxide (N2O). The fuels used as energy sources in the subject working sites are Wood Chip Fuel (WCF), RDF and Refused Plastic Fuel (RPF) of which heating values are 11.9 TJ/Gg, 17.1 TJ/Gg, and 31.2 TJ/Gg, respectively. The average concentrations of CH4 and N2O were measured to be 2.78 ppm and 7.68 ppm, respectively. The analyzed values and data collected from the field survey were used to calculate the emission factor of CH4 and N2O exhausted from the CFB boiler. As a result, the emission factors of CH4 and N2O are 1.4 kg/TJ (0.9–1.9 kg/TJ) and 4.0 kg/TJ (2.9–5.3 kg/TJ) within a 95% confidence interval. Biomass combined with the combustion technology for the CFB boiler proved to be more effective in reducing the N2O emission, compared to the emission factor of the CFB boiler using fossil fuel. PMID:23365540

  10. Development of methane and nitrous oxide emission factors for the biomass fired circulating fluidized bed combustion power plant.

    PubMed

    Cho, Chang-Sang; Sa, Jae-Hwan; Lim, Ki-Kyo; Youk, Tae-Mi; Kim, Seung-Jin; Lee, Seul-Ki; Jeon, Eui-Chan

    2012-01-01

    This study makes use of this distinction to analyze the exhaust gas concentration and fuel of the circulating fluidized bed (CFB) boiler that mainly uses wood biomass, and to develop the emission factors of Methane (CH(4)), Nitrous oxide (N(2)O). The fuels used as energy sources in the subject working sites are Wood Chip Fuel (WCF), RDF and Refused Plastic Fuel (RPF) of which heating values are 11.9 TJ/Gg, 17.1 TJ/Gg, and 31.2 TJ/Gg, respectively. The average concentrations of CH(4) and N(2)O were measured to be 2.78 ppm and 7.68 ppm, respectively. The analyzed values and data collected from the field survey were used to calculate the emission factor of CH(4) and N(2)O exhausted from the CFB boiler. As a result, the emission factors of CH(4) and N(2)O are 1.4 kg/TJ (0.9-1.9 kg/TJ) and 4.0 kg/TJ (2.9-5.3 kg/TJ) within a 95% confidence interval. Biomass combined with the combustion technology for the CFB boiler proved to be more effective in reducing the N(2)O emission, compared to the emission factor of the CFB boiler using fossil fuel.

  11. The role of thermally induced fractures in the calcination and sulfation behavior of sorbents in fluidized bed combustion

    SciTech Connect

    Liu, Y.; Morrison, J.L.; Scaroni, A.W.

    1995-12-31

    In atmospheric pressure, circulating fluidized bed combustors, sorbents are used to minimize SO{sub 2} emissions. It is generally accepted that CaO, formed by decomposition of CaCO{sub 3}, reacts with SO{sub 2} and O{sub 2}: CaCO{sub 3} {yields} CaO + CO{sub 2} and CaO + SO{sub 2} + 1/2 O{sub 2} {yields} CaSO{sub 4} rather than direct sulfation of CaCO{sub 3}: CaCO{sub 3} + SO{sub 2} + 1/2 O{sub 2} {yields} CaSO{sub 4} + CO{sub 2}. Therefore, the physical structure of a calcine, e.g. pore size distribution, accessible surface area, plays an important role in subsequent sulfation behavior. While the use of sorbents to capture SO{sub 2} from combustion gases has been in practice for decades, experimental evaluation is still necessary for selecting a sorbent for a specific application. Naturally occurring sorbents, composed of individual grains of carbonate crystallites, vary greatly in their chemical composition and physical structure. The variation in sorbent properties is often reflected in calcination and sulfation behavior. The present work involved studying the effect of particle size and grain size on the sulfation behavior of six sorbents. The samples covered a wide range of chemical compositions (limestone to dolostone), physical strengths (low to high) and grain structures (fine to coarse-grained).

  12. NO{sub x} formation and reduction during combustion of wet sewage sludge in the circulating fluidized bed -- Measurements and simulation

    SciTech Connect

    Philippek, C.; Knoebig, T.; Schoenfelder, H.; Werther, J.

    1997-12-31

    Mechanically dewatered municipal sewage sludge with a water content between 70 and 80 wt% was incinerated in a pilot-scale circulating fluidized bed (CFB). The combustion chamber had a total height of 15 m and a circular cross-section of 0.1 m diameter. In order to compensate for heat losses, the combustor was electrically heated from the outside. The combustion temperature of 850 C could thus be maintained along the whole length of the riser. Axial concentration profiles of the gaseous species O{sub 2}, CO{sub 2}, NO, N{sub 2}O, NH{sub 3} and organic carbon measured as CH{sub 4} were recorded for a variety of operating conditions. Since a major part of the investigation was devoted to the elucidation of the mechanisms of NO{sub x} formation and reduction in the case of combustion of wet sewage sludge, the combustor was also used for reaction kinetic studies whereby different gases, e.g., CO, NH{sub 3}, NO and N{sub 2}O were injected into the combustor which was during these experiments fluidized with nitrogen. The kinetic studies lead to a simplified kinetic scheme for NO{sub x} formation and reduction under conditions of sludge combustion. The combustor model divides the combustion chamber into four stages, i.e., a bottom zone, a splash-zone, an upper dilute zone and an exit zone. The bottom zone is modeled as a bubbling fluidized bed, whereas for the upper dilute zone a two-phase structure with an upflowing dilute suspension phase and a downflowing dense phase is assumed. This model is combined with a combustion model and the NO{sub x} formation and reduction model to form the CFB sludge combustor model. The calculations yield axial distributions of the different gaseous species which are shown to be fairly good agreement with the measurements. The model is able to explain the effects of different operating variables on the NO{sub x} emissions. IN particular, the model is able to explain why two-stage combustion, which in the case of coal combustion is

  13. DNA damage induced by coal dust, fly and bottom ash from coal combustion evaluated using the micronucleus test and comet assay in vitro.

    PubMed

    Matzenbacher, Cristina Araujo; Garcia, Ana Letícia Hilario; Dos Santos, Marcela Silva; Nicolau, Caroline Cardoso; Premoli, Suziane; Corrêa, Dione Silva; de Souza, Claudia Telles; Niekraszewicz, Liana; Dias, Johnny Ferraz; Delgado, Tânia Valéria; Kalkreuth, Wolfgang; Grivicich, Ivana; da Silva, Juliana

    2017-02-15

    Coal mining and combustion generating huge amounts of bottom and fly ash are major causes of environmental pollution and health hazards due to the release of polycyclic aromatic hydrocarbons (PAH) and heavy metals. The Candiota coalfield in Rio Grande do Sul, is one of the largest open-cast coal mines in Brazil. The aim of this study was to evaluate genotoxic and mutagenic effects of coal, bottom ash and fly ash samples from Candiota with the comet assay (alkaline and modified version) and micronucleus test using the lung fibroblast cell line (V79). Qualitative and quantitative analysis of PAH and inorganic elements was carried out by High Performance Liquid Chromatography (HPLC) and by Particle-Induced X-ray Emission (PIXE) techniques respectively. The samples demonstrated genotoxic and mutagenic effects. The comet assay modified using DNA-glicosilase formamidopirimidina (FPG) endonuclease showed damage related to oxidative stress mechanisms. The amount of PAHs was higher in fly ash followed by pulverized coal. The amount of inorganic elements was highest in fly ash, followed by bottom ash. It is concluded that the samples induce DNA damage by mechanisms that include oxidative stress, due to their complex composition, and that protective measures have to be taken regarding occupational and environmental hazards.

  14. The effect of fuel and sorbent properties on their partitioning between the flyash and bottom ash streams in fluidized bed combustion

    NASA Astrophysics Data System (ADS)

    Rozelle, Peter Lawrence

    2000-10-01

    The fluidized bed combustion process has been employed successfully in several applications, among which steam raising is notable. The use of circulating fluidized bed (CFB) combustion for steam and power generation offers a competitive alternative both in the United States and worldwide, yet there remain technical issues, which if addressed, can improve the competitive position of CFB boiler technology, and improve the operating economics of existing plants. Prominent among these technical issues are the performance of limestones and dolostones as sorbents for emissions control, and the ability of a plant's ash handling system to respond to changes in the fuel or sorbent used by the plant. Study of the effects of fuel and sorbent properties on the partitioning of their resultant bed particles between the ash streams, during the fluidized bed combustion process, has been carried out. This work used results from sorbent tests in a commercial CFB boiler and experimentation with laboratory fluid bed reactors. Sorbents varying in petrographic properties were used in the boiler tests as well as the laboratory testing. Fuels tested had varying distributions of ash content by specific gravity, and ranged in composite ash content from 25 to 49 wt%. Sorbent petrographic properties, described by a characteristic crystallite size, influenced the partitioning of calcium to the flyash and bottom ash streams of the boiler. Under the boiler conditions used for the sorbent tests, sorbent petrographic properties significantly influenced the sorbent consumption rate required by the boiler to maintain air quality compliance. Testing of a range of fuels was carried out in a laboratory fluid bed combustor. Ashing of different specific gravity fractions of the coarse fuel particles revealed a trend where higher specific gravity fractions of the fuel yielded coarse ash particles. A trend was found between increased presence of high ash content particles in a fuel, and increased

  15. Evaluation of cimi-shield knock-out bed bug eliminator against house fly (Musca domestica) adults.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cimi-Shield Knock-Out (CSKO) Bed Bug Eliminator is a green treatment labeled for use against bed bugs, carpet beetles, ants, roaches, fleas, ticks, silverfish, millipedes and centipedes. The active ingredient is soybean oil. If CSKO is formulated according to label instructions and sprayed directly ...

  16. Evaluation of cimi-shield knock-out bed bug eliminator against house fly (Musca domestica) adults

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cimi-Shield Knock-Out (CSKO) Bed Bug Eliminator is a green treatment labeled for use against bed bugs, carpet beetles, ants, roaches, fleas, ticks, silverfish, millipedes and centipedes. The active ingredient is soybean oil. If CSKO is formulated according to label instructions and sprayed directly ...

  17. Fundamental study of low-NOx combustion fly ash utilization. Semiannual report, May 1, 1998--October 31, 1998

    SciTech Connect

    Hurt, R.H.; Suuberg, E.M.

    1999-10-20

    The objective of the current work was to investigate the oxidation reactivity of fly ash carbons, using thermogravimetric analysis techniques. Good measures of the oxidation reactivity of fly ash carbon were the critical temperature (T{sub cr}) and the late burnout temperature (T{sub late}). The lower the critical temperature of the fly ash carbon, the more reactive the sample. By contrast, the higher T{sub late}, the less reactive the fly ash carbon. The difference between T{sub cr} and T{sub late} provided information about the reactivity distribution and was mainly dependent on fly ash carbon content (Loss-On-Ignition (LOI)). Fly ash carbons having different origins, some from lower rank coals and some from higher rank coals had slightly different reactivities. Class C fly ash carbons from low rank coals were more reactive than the typical class F fly ash carbons from higher rank coals. The reactivity parameters did not, however, provide any additional ability to predict the suitability of a given ash for use in concrete.

  18. Factors affecting cleanup of exhaust gases from a pressurized, fluidized-bed coal combustor

    NASA Technical Reports Server (NTRS)

    Rollbuhler, R. J.; Kobak, J. A.

    1980-01-01

    The cleanup of effluent gases from the fluidized-bed combustion of coal is examined. Testing conditions include the type and feed rate of the coal and the sulfur sorbent, the coal-sorbent ratio, the coal-combustion air ratio, the depth of the reactor fluidizing bed, and the technique used to physically remove fly ash from the reactor effluent gases. Tests reveal that the particulate loading matter in the effluent gases is a function not only of the reactor-bed surface gas velocity, but also of the type of coal being burnt and the time the bed is operating. At least 95 percent of the fly ash particules in the effluent gas are removed by using a gas-solids separator under controlled operating conditions. Gaseous pollutants in the effluent (nitrogen and sulfur oxides) are held within the proposed Federal limits by controlling the reactor operating conditions and the type and quantity of sorbent material.

  19. Emission and control of N2O and composition of ash derived from cattle manure combustion using a pilot-scale fluidized bed incinerator.

    PubMed

    Oshita, Kazuyuki; Kawaguchi, Koji; Takaoka, Masaki; Matsukawa, Kazutsugu; Fujimori, Takashi; Fujiwara, Taku

    2015-10-06

    This study investigates the emission of nitrous oxide (N2O) and discusses the reduction of N2O emissions during the 24-h combustion of cattle manure using a pilot-scale fluidized bed incinerator under various experimental conditions. The results of these experiments were then validated against previously reported data. In addition, the characteristics of cattle manure incineration ash and their changes under different combustion conditions were estimated. In incineration experiments with composted cattle manure, N2O concentrations using multi-stage combustion were 75% lower than the concentrations resulting from normal combustion without additional auxiliary fuel, since N2O could be decomposed in the high-temperature zone formed by the inlet of the secondary combustion air. The N2O emission factor under normal combustion conditions (800°C) was 6.0% g-N2O-N/g-N. This result is similar to the values found in previous studies at the same temperature. The N2O emission factor was decreased to 1.6% g-N2O-N/g-N using a multi-stage combustion procedure. The current Japanese N2O emission factor of 0.1% g-N2O-N/g-N is an underestimate for some conditions and should be uniquely specified for each condition. Finally, cattle manure ash contains ample fertilizer elements, little Fe, Al and Zn, but abundant Cl. Therefore if Cl could be removed by some kind of pretreatment, cattle manure ash could be used as a favourable fertilizer.

  20. Combustion characteristics and arsenic retention during co-combustion of agricultural biomass and bituminous coal.

    PubMed

    Zhou, Chuncai; Liu, Guijian; Wang, Xudong; Qi, Cuicui; Hu, Yunhu

    2016-08-01

    A combination of thermogravimetric analysis (TG) and laboratory-scale circulated fluidized bed combustion experiment was conducted to investigate the thermochemical, kinetic and arsenic retention behavior during co-combustion bituminous coal with typical agricultural biomass. Results shown that ignition performance and thermal reactivity of coal could be enhanced by adding biomass in suitable proportion. Arsenic was enriched in fly ash and associated with fine particles during combustion of coal/biomass blends. The emission of arsenic decreased with increasing proportion of biomass in blends. The retention of arsenic may be attributed to the interaction between arsenic and fly ash components. The positive correlation between calcium content and arsenic concentration in ash suggesting that the arsenic-calcium interaction may be regarded as the primary mechanism for arsenic retention.

  1. Effect of fluidising velocity on the combustion of rice husk in a bench-scale fluidised bed combustor for the production of amorphous rice husk ash.

    PubMed

    Rozainee, M; Ngo, S P; Salema, A A; Tan, K G; Ariffin, M; Zainura, Z N

    2008-03-01

    This study was focused on investigating the optimum fluidising velocity during the combustion of rice husk in a bench-scale fluidised bed combustor (ID 210mm) to obtain low carbon ash in the amorphous form. When all other parameters are held constant, the optimum fluidizing velocity aids in almost complete combustion, thereby releasing the entrapped carbon for further conversion. This results in ash with consistently low carbon content (less than 2wt%). The range of fluidising velocities investigated was from as low as 1.5U(mf) to as high as 8U(mf). It was found that the optimum fluidising velocity was approximately 3.3U(mf) as the mixing of rice husk with the bed was good with a high degree of penetration into the sand bed. The resulting ash retained its amorphous form with low residual carbon content (at 2.88wt%) and minimal sand contamination as shown by the X-ray diffraction analysis.

  2. Thermal co-treatment of combustible hazardous waste and waste incineration fly ash in a rotary kiln.

    PubMed

    Huber, Florian; Blasenbauer, Dominik; Mallow, Ole; Lederer, Jakob; Winter, Franz; Fellner, Johann

    2016-12-01

    As current disposal practices for municipal solid waste incineration (MSWI) fly ash are either associated with significant costs or negative environmental impacts, an alternative treatment was investigated in a field scale experiment. Thereto, two rotary kilns were fed with hazardous waste, and moistened MSWI fly ash (water content of 23%) was added to the fuel of one kiln with a ratio of 169kg/Mg hazardous waste for 54h and 300kg/Mg hazardous waste for 48h while the other kiln was used as a reference. It was shown that the vast majority (>90%) of the inserted MSWI fly ash was transferred to the bottom ash of the rotary kiln. This bottom ash complied with the legal limits for non-hazardous waste landfills, thereby demonstrating the potential of the investigated method to transfer hazardous waste (MSWI fly ash) into non-hazardous waste (bottom ash). The results of a simple mixing test (MSWI fly ash and rotary kiln bottom ash have been mixed accordingly without thermal treatment) revealed that the observed transformation of hazardous MSWI fly ash into non-hazardous bottom ash during thermal co-treatment cannot be referred to dilution, as the mixture did not comply with legal limits for non-hazardous waste landfills. For the newly generated fly ash of the kiln, an increase in the concentration of Cd, K and Pb by 54%, 57% and 22%, respectively, was observed. In general, the operation of the rotary kiln was not impaired by the MSWI fly ash addition.

  3. Relationship between fluid bed aerosol generator operation and the aerosol produced

    SciTech Connect

    Carpenter, R.L.; Yerkes, K.

    1980-12-01

    The relationships between bed operation in a fluid bed aerosol generator and aerosol output were studied. A two-inch diameter fluid bed aerosol generator (FBG) was constructed using stainless steel powder as a fluidizing medium. Fly ash from coal combustion was aerosolized and the influence of FBG operating parameters on aerosol mass median aerodynamic diameter (MMAD), geometric standard deviation (sigma/sub g/) and concentration was examined. In an effort to extend observations on large fluid beds to small beds using fine bed particles, minimum fluidizing velocities and elutriation constant were computed. Although FBG minimum fluidizing velocity agreed well with calculations, FBG elutriation constant did not. The results of this study show that the properties of aerosols produced by a FBG depend on fluid bed height and air flow through the bed after the minimum fluidizing velocity is exceeded.

  4. Atmospheric fluidized bed combustion advanced system concepts applicable to small industrial and commercial markets. Topical report, Level 2

    SciTech Connect

    Ake, T.R.; Dixit, V.B.; Mongeon, R.K.

    1992-09-01

    As part of an overall strategy to promote FBC coal combustion and to improve the marketability of the eastern coals, the US Department of Energy`s Morgantown Energy Research Center awarded a three level contract to Riley Stoker Corporation to develop advanced Multi Solids Fluidized Bed (MSFB) boiler designs. The first level of this contract targeted the small package boiler (10,000--50,000 lb/hr steam) and industrial size boiler (75,000--150,000 lb/hr steam) markets. Two representative sizes, 30,000 lb/hr and 110,000 lb/hr of steam, were selected for the two categories for a detailed technical and economic evaluation. Technically, both the designs showed promise, however, the advanced industrial design was favored on economic considerations. It was thus selected for further study in the second level of the contract. Results of this Level-2 effort, presented in this report, consisted of testing the design concept in Riley`s 4.4 MBtu/hr pilot MSFB facility located at Riley Research Center in Worcester, Mass. The design and economics of the proof of concept facility developed in Level-1 of the contract were then revised in accordance with the findings of the pilot test program. A host site for commercial demonstration in Level-3 of the contract was also secured. It was determined that co-firing coal in combination with paper de-inking sludge will broaden the applicability of the design beyond conventional markets. International Paper (IP), the largest paper company in the world, is willing to participate in this part of the program. IP has offered its Hammermill operation at Lockhaven, Pa, site of a future paper de-inking plant, for the proof of concept installation. This plant will go in operation in 1994. It is recommended that METC proceed to the commercial demonstration of the design developed. The approach necessary to satisfy the needs of the customer while meeting the objectives of this program is presented along with a recommended plan of action.

  5. APFBC repowering could help meet Kyoto Protocol CO{sub 2} reduction goals[Advanced Pressurized Fluidized Bed Combustion

    SciTech Connect

    Weinstein, R.E.; Tonnemacher, G.C.

    1999-07-01

    The Clinton Administration signed the 1997 Kyoto Protocol agreement that would limit US greenhouse gas emissions, of which carbon dioxide (CO{sub 2}) is the most significant. While the Kyoto Protocol has not yet been submitted to the Senate for ratification, in the past, there have been few proposed environmental actions that had continued and wide-spread attention of the press and environmental activists that did not eventually lead to regulation. Since the Kyoto Protocol might lead to future regulation, its implications need investigation by the power industry. Limiting CO{sub 2} emissions affects the ability of the US to generate reliable, low cost electricity, and has tremendous potential impact on electric generating companies with a significant investment in coal-fired generation, and on their customers. This paper explores the implications of reducing coal plant CO{sub 2} by various amounts. The amount of reduction for the US that is proposed in the Kyoto Protocol is huge. The Kyoto Protocol would commit the US to reduce its CO{sub 2} emissions to 7% below 1990 levels. Since 1990, there has been significant growth in US population and the US economy driving carbon emissions 34% higher by year 2010. That means CO{sub 2} would have to be reduced by 30.9%, which is extremely difficult to accomplish. The paper tells why. There are, however, coal-based technologies that should be available in time to make significant reductions in coal-plant CO{sub 2} emissions. Th paper focuses on one plant repowering method that can reduce CO{sub 2} per kWh by 25%, advanced circulating pressurized fluidized bed combustion combined cycle (APFBC) technology, based on results from a recent APFBC repowering concept evaluation of the Carolina Power and Light Company's (CP and L) L.V. Sutton steam station. The replacement of the existing 50-year base of power generating units needed to meet proposed Kyoto Protocol CO{sub 2} reduction commitments would be a massive undertaking. It is

  6. Fly and bottom ashes from biomass combustion as cement replacing components in mortars production: rheological behaviour of the pastes and materials compression strength.

    PubMed

    Maschio, Stefano; Tonello, Gabriele; Piani, Luciano; Furlani, Erika

    2011-10-01

    In the present research mortar pastes obtained by replacing a commercial cement with the equivalent mass of 5, 10, 20 and 30 wt.% of fly ash or bottom ash from fir chips combustion, were prepared and rheologically characterized. It was observed that the presence of ash modifies their rheological behaviour with respect to the reference blend due to the presence, in the ashes, of KCl and K2SO4 which cause precipitation of gypsum and portlandite during the first hydration stages of the pastes. Hydrated materials containing 5 wt.% of ash display compression strength and absorption at 28 d of same magnitude as the reference composition; conversely, progressive increase of ash cause a continuous decline of materials performances. Conversely, samples tested after 180 d display a marked decline of compression strength, as a consequence of potassium elution and consequent alkali-silica reaction against materials under curing.

  7. Co-combustion of coal and biomass in pulverized fuel and fluidized bed systems -- Activities and research in Europe

    SciTech Connect

    Hein, K.R.G.; Spliethoff, H.

    1999-07-01

    Biomass or sewage sludge utilized as additional fuel in coal combustion systems has consequences on combustion behavior, emissions, corrosion, and residual matter. Therefore, at the beginning of 1993 the European Union within the frame of the APAS program launched a project called ``Combined Combustion of Biomass/Sewage Sludge and Coal''. Within this project, the effects of burning sewage sludge and agricultural residuals such as straw and manure as well as specially grown energy plants in combination with coals of various ranks and origin were studied for the most common large-scale systems in order to establish both the optimum and the technically achievable process modifications necessary for co-combustion. Based on the experience of the APAS program, the objective of a further EU-co-funded project titled ``Operational problems, trace emissions and by-product management for industrial biomass co-combustion'' was to concentrate the research effort on the problem areas like slagging, fouling, corrosion, ash utilization and trace emissions for different co-combustion systems and carefully investigate technical options to avoid these negative effects. The solution of these technical problems is essential for a technically and economically feasible and environmentally advantageous co-combustion and will promote a widespread utilization of existing biomass resources. The project provides a comparison of different biomass co-utilization concepts with regard to fouling, slagging, corrosion, ash utilization and trace emissions. In detail the project incorporated biofuels like wood, wood pulp, bark, straw, wood matter from pressed olive stones and sewage sludge. The major operational problems like slagging, fouling and corrosion were investigated in both PF and CFB units of various scales. Finally the effect of co-combustion on the by-product management - handling, utilization and disposal are evaluated and compared with a pure coal or pure biomass combustion system

  8. A Contribution to the Problem of Initiation of a Combustion Source in an Oil-Saturated Bed

    NASA Astrophysics Data System (ADS)

    Koznacheev, I. A.; Dobrego, K. V.

    2013-11-01

    The problem on in-situ self-ignition of an oil-saturated bed under the conditions of forced filtration of an oxygen-containing gas has been solved with analytical and numerical methods with account of the burnout of a deficient gas component. The influence of the burnout of this component and of convective removal of heat from the bed on the time of its self-ignition has been determined. Recommendations for the optimum regime of initiation of the self-ignition of the bed with account of variation of the blast flow rate and the oxygen content have been given.

  9. Fluidized-bed boilers

    SciTech Connect

    Makansi, J.; Schwieger, B.

    1982-08-01

    This report reviews the current state of atmospheric fluidized-bed combustion. The fundamentals of fluidized-bed combustion and design considerations are first discussed. Tables provide details of manufacturers, worldwide, and of the boilers now installed. Eight plants in various countries and burning a variety of fuels, are described more fully.

  10. Co-firing a pressurized fluidized-bed combustion system with coal and refuse derived fuels and/or sludges. Task 16

    SciTech Connect

    DeLallo, M.; Zaharchuk, R.

    1994-01-01

    The co-firing of waste materials with coal in utility scale power plants has emerged as an effective approach to produce energy and manage municipal waste. Leading this approach, the atmospheric fluidized-bed combustor (AFBC) has demonstrated its commercial acceptance in the utility market as a reliable source of power burning a variety of waste and alternative fuels. The fluidized bed, with its stability of combustion, reduces the amount of thermochemical transients and provides for easier process control. The application of pressurized fluidized-bed combustor (PFBC) technology, although relatively new, can provide significant enhancements to the efficient production of electricity while maintaining the waste management benefits of AFBC. A study was undertaken to investigate the technical and economic feasibility of co-firing a PFBC with coal and municipal and industrial wastes. Focus was placed on the production of electricity and the efficient disposal of wastes for application in central power station and distributed locations. Wastes considered for co-firing include municipal solid waste (MSW), tire-derived fuel (TDF), sewage sludge, and industrial de-inking sludge. Issues concerning waste material preparation and feed, PFBC operation, plant emissions, and regulations are addressed. This paper describes the results of this investigation, presents conclusions on the key issues, and provides recommendations for further evaluation.

  11. Second-generation pressurized fluidized-bed combustion plant: Conceptual design and optimization of a second-generation PFB combustion plant. Phase 2, Annual report, October 1991--September 1992

    SciTech Connect

    Robertson, A.; Domeracki, W.; Newby, R.; Rehmat, A.; Horazak, D.

    1992-10-01

    After many years of experimental testing and development work, coal-fired pressurized fluidized bed (PFB) combustion combined-cycle power plants are moving toward reality. Under the US Department of Energy`s Clean Coal Technology Program, a 70-MWe PFB combustion retrofit, utilizing a 1525{degrees}F gas turbine inlet temperature, has been built and operated as a demonstration plant at the American Electric Power Company`s Tidd Plant in Brilliant, Ohio. As PFB combustion technology moves closer and closer to commercialization, interest is turning toward the development of an even more efficient and more cost-effective PFB combustion plant. The targeted goals of this ``second-generation`` plant are a 45-percent efficiency and a cost of electricity (COE) that is at least 20 percent lower than the COE of a conventional pulverized-coal (PC)-fired plant with stack gas scrubbing. In addition, plant emissions should be within New Source Performance Standards (NSPS) and the plant should have high availability, be able to burn different ranks of coal, and incorporate modular construction technologies. In response to this need, a team of companies led by Foster Wheeler Development Corporation (FWDC). The key components in the proposed second-generation plant are the carbonizer, CPFBC, ceramic cross-flow filter, and topping combustor. Unfortunately, none of these components has been operated at proposed plant operating conditions, and experimental tests must be conducted to explore/determine their performance throughout the proposed plant operating envelope. The major thrust of Phase 2 is to design, construct, test, and evaluate the performance of the key components of the proposed plant.

  12. Three-zonal engineering method of heat calculation for fluidized bed furnaces based on data on commercial investigations of heat generation distribution during biomass combustion

    NASA Astrophysics Data System (ADS)

    Litun, D. S.; Ryabov, G. A.

    2016-02-01

    A three-zonal method of heat calculation of furnaces for combustion of biomass and low-caloric fuel in the fluidized bed is described. The method is based on equations of thermal and material balances that account for heat generation by fuel in the zone, heat-and-mass transfer heat exchange between the furnace media and surfaces that bound the zone, and heat-and-mass transfer between furnace zones. The calculation procedure for heat generation by fuel in the fluidized bed (FB) using the heat generation portion by the fuel is proposed. Based on commercial investigations, the main factors that affect the average temperature in the FB and the portion of fuel heat that is released in the FB are determined. Results of commercial investigations showed that the airflow coefficient in the FB should be recognized as the main operation parameter that affects the average temperature in the FB and, consequently, heat generation in the FB. The gas flow rate in the FB can be marked out as the second factor that affects the consumption degree of oxidizer supplied in the FB. Commercial investigations revealed that mixing is affected by the gas flow rate in the FB and the bed material particle size, which may be changed during the boiler operation because of the agglomeration of particles of sand and ash. The calculation processing of commercial investigations on a KM-75-40M boiler of a CHP-3 of an Arkhangelsk Pulp and Paper Mill (APPM), which was carried out using the inverse problem procedure by means of a developed computer program, determined the range of the fuel heat release share in the FB, which was 0.26-0.45 at an excess air factor of 0.59-0.93 in the bed, and the heat release share in the maximum temperature zone in the total heat release in the superbed space. The heat release share in the bed is determined as an approximating function of the excess air factor in the bed and the fluidization number. The research results can be used during designing boilers with the

  13. Behavior of fluorine and chlorine in Spanish coal fired power plants with pulverized coal boilers and fluidized bed boiler.

    PubMed

    López-Vilariño, J M; Fernández-Martínez, G; Turnes-Carou, I; Muinategui-Lorenzo, S; López-Mahía, P; Prada-Rodríguez, D

    2003-06-01

    Behavior and contents of fluorine and chlorine in coal feedstock, combustion wastes (slag and fly ash) and emissions were studied in five conventional coal fired power plants and in a fluidized bed coal power plant. The halide levels found in the used coal were quite low. Mass balances and emission factors were calculated. The volatility of these elements makes the gaseous emission the main target between the residues. The influence of combustion parameters is not clearly established. Several analytical techniques (ion selective electrodes, capillary electrophoresis and ion chromatography) are employed to determinate the halide concentration in the different samples taken in the power plants studied (coal, slag, fly ash and flue gases).

  14. Disposal of fluidized bed combustion ash in an underground mine to control acid mine drainage and subsidence - phase II - small scale field demonstration. Topical report, December 1, 1996--February 28, 1997

    SciTech Connect

    Ziemkiewicz, P.F.; Head, W.J.; Gray, D.D.; Siriwardane, H.J.; Sack, W.A.

    1998-01-01

    It has been proposed that a mix made from fly and bottom ash from atmospheric pressure fluidized bed coal combusters (FBC ash), water, and stabilizers be injected from the surface into abandoned room and pillar coal mines through boreholes. Besides ash disposal, this process would prevent subsidence and acid mine drainage. Such a mix (called `grout`) needs to be an adequately stable and flowable suspension for it to spread and cover large areas in the mine. This is necessary as the drilling of the boreholes will be an expensive operation and the number such holes should be minimized. Addition of bentonite was found to be needed for this purpose. A suitable grout mix was tested rheologically to determine its fluid flow properties. Finding little published information on such materials, tests were performed using a commercial rotational viscometer with a T-bar rotor and a stand which produced a helical rotor path. Existing mixer viscometer test methods were modified and adapted to convert the measurements of torque vs. angular speed to the material properties appearing in several non-Newtonian constitutive equations. Yield stress was measured by an independent test called the vane method. The rheological behavior was a close fit to the Bingham fluid model. Bleed tests were conducted to ascertain the stability of the mixtures. Spread tests were conducted to compare the flowability of various mixes. Using the flow parameters determined in the laboratory, numerical simulations of grout flow were performed and compared with the results of scale model and field tests. A field injection of this grout was performed at the Fairfax mines in Preston county, W.V.. The observations there proved that this FBC ash grout flows as desired, is a very economical way of disposing the environmentally menacing ash, while also preventing the subsidence and acid mine drainage of the mines.

  15. Preliminary evaluation of coal-fired fluid bed combustion-augmented compressed air energy storage power plants

    NASA Astrophysics Data System (ADS)

    Lessard, R. D.; Giramonti, A. J.; Merrick, D.

    1980-03-01

    This paper presents highlights of an ongoing study program to assess the technical and economic feasibility of advanced concepts for generating peak-load electric power from a compressed air energy storage (CAES) power plant incorporating a coal-fired fluid bed combustor (FBC). It reviews the analyses performed to select an FBC/CAES power plant system configuration for the subsequent conceptual design phase of the study. Included in this review are: the design and operating considerations involved with integrating either an atmospheric or a pressurized fluid bed combustor with a CAES system to yield practical system configurations; the integration of system configurations; the parametric performance of these system configurations; and the preliminary screening which considered performance, cost, and technical risk and led to the identification of an open-bed PFBC/CAES system as having the greatest near-term commercialization potential.

  16. A refrigerated web camera for photogrammetric video measurement inside biomass boilers and combustion analysis.

    PubMed

    Porteiro, Jacobo; Riveiro, Belén; Granada, Enrique; Armesto, Julia; Eguía, Pablo; Collazo, Joaquín

    2011-01-01

    This paper describes a prototype instrumentation system for photogrammetric measuring of bed and ash layers, as well as for flying particle detection and pursuit using a single device (CCD) web camera. The system was designed to obtain images of the combustion process in the interior of a domestic boiler. It includes a cooling system, needed because of the high temperatures in the combustion chamber of the boiler. The cooling system was designed using CFD simulations to ensure effectiveness. This method allows more complete and real-time monitoring of the combustion process taking place inside a boiler. The information gained from this system may facilitate the optimisation of boiler processes.

  17. A Refrigerated Web Camera for Photogrammetric Video Measurement inside Biomass Boilers and Combustion Analysis

    PubMed Central

    Porteiro, Jacobo; Riveiro, Belén; Granada, Enrique; Armesto, Julia; Eguía, Pablo; Collazo, Joaquín

    2011-01-01

    This paper describes a prototype instrumentation system for photogrammetric measuring of bed and ash layers, as well as for flying particle detection and pursuit using a single device (CCD) web camera. The system was designed to obtain images of the combustion process in the interior of a domestic boiler. It includes a cooling system, needed because of the high temperatures in the combustion chamber of the boiler. The cooling system was designed using CFD simulations to ensure effectiveness. This method allows more complete and real-time monitoring of the combustion process taking place inside a boiler. The information gained from this system may facilitate the optimisation of boiler processes. PMID:22319349

  18. Effect of SiO2/Na2O mole ratio on the properties of foam geopolymers fabricated from circulating fluidized bed fly ash

    NASA Astrophysics Data System (ADS)

    Liu, Ze; Shao, Ning-ning; Huang, Tian-yong; Qin, Jun-feng; Wang, Dong-min; Yang, Yu

    2014-06-01

    Geopolymers are three-dimensional aluminosilicates formed in a short time at low temperature by geopolymerization. In this paper, alkali-activated foam geopolymers were fabricated from circulating fluidized bed fly ash (CFA), and the effect of SiO2/Na2O mole ratio (0.91-1.68) on their properties was studied. Geopolymerization products were characterized by mechanical testing, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The results show that SiO2/Na2O mole ratio plays an important role in the mechanical and morphological characteristics of geopolymers. Foam samples prepared in 28 d with a SiO2/Na2O mole ratio of 1.42 exhibit the greatest compressive strength of 2.52 MPa. Morphological analysis reveals that these foam geopolymers appear the relatively optimized pore structure and distribution, which are beneficial to the structure stability. Moreover, a combination of the Si/Al atomic ratio ranging between 1.47 and 1.94 with the Na/Al atomic ratio of about 1 produces the samples with high strength.

  19. Sampling and analysis of hydrocarbons in combustion gases. Annual report, October 1979-September 1980

    SciTech Connect

    Johnson, I.; Myles, K.M.; Siczek, A.A.

    1981-04-01

    The purpose of these studies is to develop a method for the chemical analysis of ultratrace levels of polycyclic organic compounds in the flue gases from fluidized-bed combustors. Methods which have the potential for real time analysis have been studied. Two methods, double mass spectrometry and laser ionization mass spectrometry, appear to be promising. A brief review of current analytical methods has been made. A brief examination of fly ash from fluidized-bed combustion revealed no carcinogenic species although samples collected during fluidized-bed combustor startup were found to be mutagenic.

  20. Co-combustion of coal and sewage sludge: chemical and ecotoxicological properties of ashes.

    PubMed

    Barbosa, Rui; Lapa, Nuno; Boavida, Dulce; Lopes, Helena; Gulyurtlu, Ibrahim; Mendes, Benilde

    2009-10-30

    The co-combustion of sewage sludge (SS) and coal is widely used for the treatment and thermal valorization of SS produced in wastewater treatment plants. The chemical and ecotoxicological properties of the ashes produced in this thermal treatment have not been fully studied. Two combustion tests were performed in a fluidized bed combustor. Colombian coal was used as fuel in test A. A blend (1+1) of this coal and a stabilized SS (Biogran) was used in a second test B. Samples of the bottom and fly ashes trapped in two sequential cyclones were collected. The characterization of the ashes was focused on two main aspects: (1) the bulk content of a set of metals and (2) the characterization of eluates produced according to the European Standard leaching test EN 12457-2. The eluates were submitted to an ecotoxicological characterization for two bio-indicators. In what concerns the bulk content of ashes, both combustion tests have produced ashes with different compositions. The ashes formed during the co-combustion test have shown higher concentrations of metals, namely Cr, Cu, Ni, Pb, Zn and Fe for all ashes. The leaching test has shown low mobility of these elements from the by-products produced during the combustion and co-combustion tests. Cr and Cr(VI) were mainly detected in the eluates of the 1st cyclone ashes produced in both combustion tests and in the 2nd cyclone ashes produced in the co-combustion test. Considering the ecotoxicity assays, the eluates of bottom and fly ashes for both combustion and co-combustion tests have shown low ecotoxic levels. The micro-crustacean Daphnia magna was generally more sensitive than the bacterium Vibrio fischeri. CEMWE criterion has allowed to classify the bottom ashes for both combustion and co-combustion tests as non-toxic residues and the fly ashes collected in both cyclones as toxic.

  1. Differential behaviour of combustion and gasification fly ash from Puertollano Power Plants (Spain) for the synthesis of zeolites and silica extraction.

    PubMed

    Font, O; Moreno, N; Díez, S; Querol, X; López-Soler, A; Coca, P; Peña, F García

    2009-07-15

    Coal gasification (IGCC) and pulverised coal combustion (PCC) fly ashes (FAs), obtained from two power plants fed with the carboniferous bituminous coal from Puertollano (Spain), were characterised and used as raw materials for zeolite synthesis by direct conversion (DC) and by alkaline fusion (Fu), and SiO2 extraction (Si-Ex) at laboratory scale. The Puertollano FAs are characterised by a high SiO2 content (59%) with respect to EU coal FAs. High zeolite synthesis yields were obtained from both FAs by using conventional alkaline activation. However, the Si extraction yields were very different. The results of the zeolite synthesis from the Si-bearing extracts from both FAs demonstrated that high purity zeolites with high cation exchange capacity (CEC, between 4.3 and 5.3meq/g) can be produced. The solid residue arising from Si-Ex is also a relatively high NaP1 zeolite product (CEC 2.4-2.7 meq/g) equivalent to the DC products. The zeolitic materials synthesised from both FAs by Fu showed an intermediate (between the high purity zeolites and the DC products) zeolite content with CEC values from 3.4 to 3.7 meq/g. Low leachable metal contents were obtained from high purity A and X zeolites and zeolite material synthesised by Fu for PCC FA.

  2. Finial Scientific/Technical Report: Application of a Circulating Fluidized Bed Process for the Chemical Looping Combustion of Solid Fuel

    SciTech Connect

    Dr. Wei-Ping Pan; Dr. John T. Riley

    2005-10-10

    Chemical Looping Combustion is a novel combustion technology for the inherent separation of the greenhouse gas, CO{sub 2}. In 1983, Richter and Knoche proposed reversible combustion, which utilized both the oxidation and reduction of metal. Metal associated with its oxidized form as an oxygen carrier was circulated between two reactors--oxidizer and reducer. In the reducer, the solid oxygen carrier reacts with the fuel to produce CO{sub 2}, H{sub 2}O and elemental metal only. Pure CO{sub 2} will be obtained in the exit gas stream from the reducer after H{sub 2}O is condensed. The pure CO{sub 2} is ready for subsequent sequestration. In the oxidizer, the elemental metal reacts with air to form metal oxide and separate oxygen from nitrogen. Only nitrogen and some unused oxygen are emitted from the oxidizer. The advantage of CLC compared to normal combustion is that CO{sub 2} is not diluted with nitrogen but obtained in a relatively pure form without any energy needed for separation. In addition to the energy-free purification of CO{sub 2}, the CLC process also provides two other benefits. First, NO{sub x} formation can be largely eliminated. Secondly, the thermal efficiency of a CLC system is very high. Presently, the CLC process has only been used with natural gas. An oxygen carrier based on an energy balance analysis and thermodynamics analysis was selected. Copper (Cu) seems to be the best choice for the CLC system for solid fuels. From this project, the mechanisms of CuO reduction by solid fuels may be as follows: (1) If pyrolysis products of solid fuels are available, reduction of CuO could start at about 400 C or less. (2) If pyrolysis products of solid fuels are unavailable and the reduction temperature is lower, reduction of CuO could occur at an onset temperature of about 500 C, char gasification reactivity in CO{sub 2} was lower at lower temperatures. (3) If pyrolysis products of solid fuels are unavailable and the reduction temperature is higher than 750 C

  3. The behaviour of ashes and heavy metals during the co-combustion of sewage sludges in a fluidised bed

    SciTech Connect

    Helena Lopes, M.; Abelha, P.; Lapa, N.; Oliveira, J.S.; Cabrita, I.; Gulyurtlu, I

    2003-07-01

    Co-combustion tests of dry sewage sludges with coal were performed in a pilot bubbling FBC aiming at the characterization of ashes and determining the behaviour of heavy metals in the process. The tests showed compliance with the regulatory levels as far as heavy metal emissions were concerned. The bottom ashes, which accounted for about 70% of the total ash production, were obtained in a granular form, with diameters ranging from 0.5 to 4 mm. The heavy metals were distributed in ashes obtained from different locations of the installation and their concentrations were found to vary depending on the location of capture. The increase in heavy metals content in bottom ashes was not found to lead to higher leachability and ecotoxicity compared to sewage sludges, suggesting that there could be opportunities for their further use. Mercury suffered vaporisation inside the reactor, thus leaving bottom ashes free of contamination by it. However, there was observed a strong retention of mercury in cyclone ashes due to the presence of unburned carbon which probably acted as an adsorbent. The effluent mercury was also found to be mostly associated with the particulate fraction, being less than 20% emitted in gaseous forms. The results suggested that the combustion of the sewage sludge could successfully be carried out and the amount of unburned carbon leaving the combustor but captured in cyclone was large enough to ensure substantial retention of mercury at low temperatures, hence could contribute to an improvement of the mercury release which still remains an issue of great concern to resolve during combustion of waste materials.

  4. The combustion of large particles of char in bubbling fluidized beds: The dependence of Sherwood number and the rate of burning on particle diameter

    SciTech Connect

    Dennis, J.S.; Hayhurst, A.N.; Scott, S.A.

    2006-11-15

    burning char particle; the implication of this correlation is that a completely new picture emerges for the combustion of a char particle in a hot fluidized bed. (author)

  5. TENORM: Coal Combustion Residuals

    EPA Pesticide Factsheets

    Burning coal in boilers to create steam for power generation and industrial applications produces a number of combustion residuals. Naturally radioactive materials that were in the coal mostly end up in fly ash, bottom ash and boiler slag.

  6. Performance and economics of co-firing a coal/waste slurry in advanced fluidized-bed combustion

    SciTech Connect

    DeLallo, M.R.; Zaharchuk, R.; Reuther, R.B.; Bonk, D.L.

    1996-09-01

    This study`s objective was to investigate co-firing a pressurized fluidized-bed combustor with coal and refuse-derived fuel for the production of electricity and the efficient disposal of waste. Performance evaluation of the pressurized fluidized-bed combustor (PFBC) power plant co-fired with refuse-derived fuel showed only slightly lower overall thermal efficiency than similar sized plants without waste co-firing. Capital costs and costs of electricity are within 4.2 percent and 3.2 percent, respectively, of waste-free operation. The results also indicate that there are no technology barriers to the co-firing of waste materials with coal in a PFBC power plant. The potential to produce cost-competitive electrical power and support environmentally acceptable waste disposal exists with this approach. However, as part of technology development, there remain several design and operational areas requiring data and verification before this concept can realize commercial acceptance. 3 refs., 3 figs., 4 tabs.

  7. Comparison of ash behavior of different fuels in fluidised bed combustion using advanced fuel analysis and global equilibrium calculations

    SciTech Connect

    Zevenhoven-Onderwater, M.; Blomquist, J.P.; Skrifvars, B.J.; Backman, R.; Hupa, M.

    1999-07-01

    The behavior of different ashes is predicted by means of a combination of an advanced fuel analysis and global equilibrium calculations. In order to cover a broad spectrum of fuels a coal, a peat, a forest residue and Salix (i.e. willow) are studied. The latter was taken with and without soil contamination, i.e. with a high and low content of silica , respectively. It is shown that mineral matter in fossil and biomass fuels can be present in the matrix of the fuel itself or as included minerals. Using an advanced fuel analysis, i.e. a fractionation method, this mineral content can be divided into four fractions. The first fraction mainly contains those metal ions, that can be leached out of the fuel by water and mainly contains alkali sulfates, carbonates and chlorides. The second fraction mainly consists of those ions leached out by ammonium acetate and covers those ions, that are connected to the organic matrix. The third fraction contains the metals leached out by hydrochloric acid and contains earth alkali carbonates and sulfates as well as pyrites. The rest fraction contains those minerals, that are not leached out by any of the above mentioned solvents, such as silicates. A global equilibrium analysis is used to predict the thermal and chemical behavior of the combined first and second fractions and of the combined third and rest fractions under pressurized and/or atmospheric combustion conditions. Results of both the fuel analysis and the global equilibrium analysis are discussed and practical implications for combustion processes are pointed out.

  8. Scramjet Combustion Processes

    DTIC Science & Technology

    2010-09-01

    plan for these flights is as follows: Scramjet Combustion Processes RTO-EN-AVT-185 11 - 21 HyShot 5 – A Free-Flying Hypersonic Glider HyShot...5 will be a hypersonic glider designed to fly at Mach 8. It will separate from its rocket booster in space and perform controlled manoeuvres as it...RTO-EN-AVT-185 11 - 1 Scramjet Combustion Processes Michael Smart and Ray Stalker Centre for Hypersonics The University of Queensland

  9. Control methods for mitigating biomass ash-related problems in fluidized beds.

    PubMed

    Vamvuka, D; Zografos, D; Alevizos, G

    2008-06-01

    Embodiment of biomass combustion technologies in the Cretan energy system will play an important role and will contribute to the local development. The main biomass fuels of Crete are the agricultural residues olive kernel and olive tree wood. Future applications of these biofuels may create, among others, operational problems related to ash effects. In this regard, the thermal behavior of the ashes during lab-scale fluidized bed combustion tests was examined, in terms of slagging/fouling and agglomeration of bed material. Control methodologies for mitigating ash problems were applied, such as leaching the raw fuels with water and using different mineral additives during combustion. The ashes and the bed material were characterized in terms of mineralogical, chemical and morphological analyses and the slagging/fouling and agglomeration propensities were determined. The results showed that fly ashes were rich in Ca, Si and Fe minerals and contained substantial amounts of alkali, falling within the range of "certain or probable slagging/fouling". Leaching of the raw fuels with water resulted in a significant reduction of the problematic elements K, Na, Cl and S in the fly ashes. The use of fuel additives decreased the concentrations of alkali and iron minerals in the fly ashes. With clay additives calcium compounds were enriched in the bottom ash, while with carbonate additives they were enriched in the fly ash. Fuel additives or water leaching reduced the slagging/fouling potential due to alkali. Under the conditions of the combustion tests, no signs of ash deposition or bed agglomeration were noticed.

  10. Disposal of fluidized bed combustion ash in an underground mine to control acid mine drainage and subsidence. Quarterly report, December 1, 1996--February 28, 1997

    SciTech Connect

    1997-12-31

    This project will evaluate the technical, economic and environmental feasibility of filling abandoned underground mine voids with alkaline, advanced coal combustion wastes (Fluidized Bed Combustion-FBC ash). Success will be measured in terms of technical feasibility of the approach (i.e. % void filling), cost, environmental benefits (acid mine drainage and subsidence control) and environmental impacts (noxious ion release). During Phase 3 the majority of the activity involves completing two full scale demonstration projects. The eleven acre Longridge mine in Preston County will be filled with 53,000 cubic yards of grout during the summer of 1997 and monitored for the following year. The second demonstration involves stowing 2,000 tons of ash into an abandoned mine to demonstrate the newly redesigned Burnett Ejector. This demonstration is anticipated to take place during Summer 1997, as well. This document will report on progress made during Phase 3. The report will be divided into four major sections. The first will be the Hydraulic Injection component. This section of the report will report on progress and milestones associated with the grouting activities of the project. The Phase 3 tasks of Economic Analysis and Regulatory Analysis is covered under this section. The second component is Pneumatic Injection. This section reports on progress made towards completing the demonstration project. The Water Quality component involves background monitoring of water quality and precipitation at the Phase 3 (Longridge) mine site. The last component involves evaluating the migration of contaminants through the grouted mine. A computer model has been developed in earlier phases and will model the flow of water in and around the grouted Longridge mine. The Gantt Chart on the following page details progress by task.

  11. Effect of temperature on reduction of CaSO{sub 4} oxygen carrier in chemical-looping combustion of simulated coal gas in a fluidized bed reactor

    SciTech Connect

    Song, Q.L.; Xiao, R.; Deng, Z.Y.; Shen, L.H.; Xiao, J.; Zhang, M.Y.

    2008-12-15

    Chemical-looping combustion (CLC) is a promising combustion technology for gaseous and solid fuel with efficient use of energy and inherent separation of CO{sub 2}. The concept of a coal-fueled CLC system using, calcium sulfate (CaSO{sub 4}) as oxygen carrier is proposed in this study. Reduction tests of CaSO{sub 4} oxygen carrier with simulated coal gas were performed in a laboratory-scale fluidized bed reactor in the temperature range of 890-950{degree}C. A high concentration of CO{sub 2} was obtained at the initial reduction period. CaSO{sub 4} oxygen carrier exhibited high reactivity initially and decreased gradually at the late period of reduction. The sulfur release during the reduction of CaSO{sub 4} as oxygen carrier was also observed and analyzed. H{sub 2} and CO{sub 2} conversions were greatly influenced by reduction temperature. The oxygen carrier conversion and mass-based reaction rates during the reduction at typical temperatures were compared. Higher temperatures would enhance reaction rates and result in high conversion of oxygen carrier. An XRD patterns study indicated that CaS was the dominant product of reduction and the variation of relative intensity with temperature is in agreement with the solid conversion. ESEM analysis indicated that the surface structure of oxygen carrier particles changed significantly from impervious to porous after reduction. EDS analysis also demonstrated the transfer of oxygen from the oxygen carrier to the fuel gas and a certain amount of sulfur loss and CaO formation on the surface at higher temperatures. The reduction kinetics of CaSO{sub 4} oxygen carrier was explored with the shrinking unreacted-core model. The apparent kinetic parameters were obtained, and the kinetic equation well predicted the experimental data. Finally, some basic considerations on the use of CaSO{sub 4} oxygen carrier in a CLC system for solid fuels were discussed.

  12. Disposal of fluidized bed combustion ash in an underground mine to control acid mine drainage and subsidence. Quarterly report, December 1, 1996--February 28, 1997

    SciTech Connect

    1997-12-31

    This project will evaluate the technical, economic and environmental feasibility of filling abandoned underground mine voids with alkaline, advanced coal combustion wastes (Fluidized Bed Combustion -- FBC ash). Success will be measured in terms of technical feasibility of the approach (i.e. % void filling), cost, environmental benefits (acid mine drainage and subsidence control) and environmental impacts (noxious ion release). During Phase 3 the majority of the activity involves completing two full scale demonstration projects. The eleven acre Longridge mine in Preston County will be filled with 53,000 cubic yards of grout during the summer of 1997 and monitored for the following year. The second demonstration involves stowing 2,000 tons of ash into an abandoned mine to demonstrate the newly redesigned Burnett Ejector. This demonstration is anticipated to take place during Summer 1997, as well. This document will report on progress made during Phase 3. The report will be divided into four major sections. The first will be the Hydraulic Injection component. This section of the report will report on progress and milestones associated with the grouting activities of the project. The Phase 3 tasks of Economic Analysis and Regulatory Analysis will be covered under this section. The second component is Pneumatic Injection. This section reports on progress made towards completing the demonstration project. The Water Quality component involves background monitoring of water quality and precipitation at the Phase 3 (Longridge) mine site. The last component involves evaluating the migration of contaminants through the grouted mine. A computer model has been developed in earlier phases and will model the flow of water in and around the grouted Longridge mine.

  13. The atmospheric bubbling fluidized bed combustion of coal in the Netherlands, cleaner it can't be

    SciTech Connect

    van Gasselt, M.L.G. )

    1991-01-01

    The use of coal in atmospheric bubbling fluidized bed combustors for the generation of process steam is still a viable option for industrial applications world wide but interest in this as and electricity generation technology has also grown. The general advantages of AB-FBC are environmental acceptability and great fuel flexibility. As will be shown in this paper, it has a great potential for meeting possible future, even more stringent, regulations. Since 1979, Stork Boilers, TNO and Twente University have been carrying out a joint national research programme aimed at the design of industrial installations operating to stringent emission standards. This has led to the demonstration of a 90 MWth industrial boiler at the AKZO Chemical Works. The work has been under the control of NOVEM, the Netherlands Agency of Energy and the Environment. This body provides the financial resources on behalf of the Dutch Ministry of Economic Affairs by awarding annual contracts.

  14. Investigation in NO{sub x}-formation at combustion of sewage sludge in a commercial scale bubbling fluidized bed

    SciTech Connect

    Albrecht, J.; Schelhaas, K.P.

    1997-12-31

    In 1993, the central sludge incineration plant at Dordrecht (NL) was commissioned. This plant disposes of the residues of 100 local sewage works; in three identical trains app. 54,000 t/a of dry matter are incinerated, each train treats app. 10--12t/h of raw sludge (app. 7.5 MW); a fourth train is currently under construction and will be commissioned shortly. For a test period of 24 h NO{sub x} emissions may vary between {approximately}50 mg/m{sub n}{sup 3} and approximately 600--800 mg/m{sub n}{sup 3} at process upsets. The experimentally well defined correlation of NO{sub x}-formation even under large scale operating conditions serves as a starting point for further process modelling. Conclusions are: for fluctuating operating condition of a large scale commercial plant NO{sub x}-emissions are closely related to fluid bed temperatures; by controlling fluid temperatures NO{sub x}-emissions can be maintained at approximately <200 mg/m{sub n}{sup 3}; effects of operating condition like feed moisture or O{sub 2}-concentration in flue gas are secondary and relate to changes in temperature profile; and for a wide range of operating conditions the NO{sub x}-formation can be modelled by a pseudo first order reaction with good agreement of experimental and theoretical data.

  15. Determination of flue gas alkali concentrations in fluidized-bed coal combustion by excimer-laser-induced fragmentation fluorescence

    SciTech Connect

    Hartinger, K.T.; Monkhouse, P.B.; Wolfrum, J.; Baumann, H.; Bonn, B.

    1994-12-31

    Gas-phase sodium concentrations were measured for the first time in situ in the flue gas of a fluidized-bed reactor by the excimer-laser-induced fragmentation fluorescence (ELIF) technique. This method involves using ArF-excimer laser light at 193 nm to simultaneously photodissociate the alkali compounds of interest and excite electronically the alkali atoms formed. The resulting fluorescence from Na (3{sup 2}P) atoms can he readily detected at 589 nm. Measured signals were converted to absolute concentrations using a calibration system that monitors alkali compounds under known conditions of temperature, pressure, and composition and rising the same optical setup as at the reactor. Several different coals were investigated under a specific set of reactor conditions at total pressures close to 1 bar. Sodium concentrations ranging from the sub-ppb region to 20 ppb were obtained, and a detection limit for sodium of 0.1 ppb under the present conditions was estimated. Over the course of the reactor program, contrasting concentration histories were observed for the two lignites and the hard coal investigated. In particular, significantly higher sodium concentrations were found for the hard coal, consistent with both the higher chlorine and sodium contents determined in the corresponding coal analysis.

  16. DISPOSAL OF FLUIDIZED BED COMBUSTION ASH IN AN UNDERGROUND MINE TO CONTROL ACID MINE DRAINAGE AND SUBSIDENCE

    SciTech Connect

    Unknown

    2000-10-01

    This project evaluated the technical, economic and environmental feasibility of filling abandoned underground mine voids with coal combustion byproducts. Success was measured in terms of technical feasibility of the approach (i.e. % void filling), cost, environmental benefits (acid mine drainage and subsidence control) and environmental impacts (noxious ion release). Phase 1 of the project was completed in September 1995 and was concerned with the development of the grout and a series of predictive models. These models were verified through the Phase II field phase and will be further verified fin the large scale field demonstration of Phase III. The verification allows the results to be packaged in such a way that the technology can be easily adapted to different site conditions. Phase II was successfully completed with 1000 cubic yards of grout being injected into Anker Energy's Fairfax mine. The grout flowed over 600 feet from a single injection borehole. The grout achieved a compressive strength of over 1000 psi (twice the level that is needed to guarantee subsidence control). Phase III was a full scale test at Anker's eleven acre Longridge mine site. The CCB grout replaced what was an open mine void with a solid so that the groundwater tends to flow around and through the pillars rather than through the previously mined areas. The project has demonstrated that CCBs can be successfully disposed in underground mines. Additionally, the project has shown that filling an abandoned underground mine with CCBs can lead to the reduction and elimination of environmental problems associated with underground mining such as acid mine drainage and subsidence. The filling of the Longridge Mine with 43,000 cubic yards of CCB grout resulted in a 97% reduction in acid mine drainage coming from the mine.

  17. Adsorption with biodegradation for decolorization of reactive black 5 by Funalia trogii 200800 on a fly ash-chitosan medium in a fluidized bed bioreactor-kinetic model and reactor performance.

    PubMed

    Lin, Yen-Hui; Lin, Wen-Fan; Jhang, Kai-Ning; Lin, Pei-Yu; Lee, Mong-Chuan

    2013-02-01

    A non-steady-state mathematical model system for the kinetics of adsorption and biodegradation of reactive black 5 (RB5) by Funalia trogii (F. trogii) ATCC 200800 biofilm on fly ash-chitosan bead in the fluidized bed process was derived. The mechanisms in the model system included adsorption by fly ash-chitosan beads, biodegradation by F. trogii cells and mass transport diffusion. Batch kinetic tests were independently performed to determine surface diffusivity of RB5, adsorption parameters for RB5 and biokinetic parameters of F. trogii ATCC 200800. A column test was conducted using a continuous-flow fluidized bed reactor with a recycling pump to approximate a completely-mixed flow reactor for model verification. The experimental results indicated that F. trogii biofilm bioregenerated the fly ash-chitosan beads after attached F. trogii has grown significantly. The removal efficiency of RB5 was about 95 % when RB5 concentration in the effluent was approximately 0.34 mg/L at a steady-state condition. The concentration of suspended F. trogii cells reached up to about 1.74 mg/L while the thickness of attached F. trogii cells was estimated to be 80 μm at a steady-state condition by model prediction. The comparisons of experimental data and model prediction show that the model system for adsorption and biodegradation of RB5 can predict the experimental results well. The approaches of experiments and mathematical modeling in this study can be applied to design a full-scale fluidized bed process to treat reactive dye in textile wastewater.

  18. Fluidized bed combustor modeling

    NASA Technical Reports Server (NTRS)

    Horio, M.; Rengarajan, P.; Krishnan, R.; Wen, C. Y.

    1977-01-01

    A general mathematical model for the prediction of performance of a fluidized bed coal combustor (FBC) is developed. The basic elements of the model consist of: (1) hydrodynamics of gas and solids in the combustor; (2) description of gas and solids contacting pattern; (3) kinetics of combustion; and (4) absorption of SO2 by limestone in the bed. The model is capable of calculating the combustion efficiency, axial bed temperature profile, carbon hold-up in the bed, oxygen and SO2 concentrations in the bubble and emulsion phases, sulfur retention efficiency and particulate carry over by elutriation. The effects of bed geometry, excess air, location of heat transfer coils in the bed, calcium to sulfur ratio in the feeds, etc. are examined. The calculated results are compared with experimental data. Agreement between the calculated results and the observed data are satisfactory in most cases. Recommendations to enhance the accuracy of prediction of the model are suggested.

  19. Synthesis of multiwalled carbon nanotubes on fly ash derived catalysts.

    PubMed

    Dunens, Oscar M; MacKenzie, Kieran J; Harris, Andrew T

    2009-10-15

    Carbon nanotubes (CNTs) are an allotrope of carbon with unique properties that make them potentially useful in a vast range of applications. However, CNTs are predominantly produced using expensive and/or nonrecyclable catalyst supports, e.g., mesoporous silica and alumina. In this work, coal combustion fly ash, a bulk waste product with limited uses, was impregnated with iron nitrate and successfully used as a substrate to produce industrial grade multiwalled carbon nanotubes (MWNTs) by fluidized bed chemical vapor deposition. CNTs were analyzed using thermogravimetric analysis, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The most successful catalyst trialed at 650 degrees C using ethylene as a carbon source was a 5 wt % Fe fly ash catalyst, which produced a CNT yield in respect to metal loading of approximately 82.5%. The MWNTs had outer diameters of between 12 and 20 nm with a reasonable degree of wall graphitization (I(G)/I(D) of 1.17). Advantages of utilizing fly ash as a catalyst support are its availability at low cost at the megaton scale, its high thermal stability, and suitability for use in industrial fluidized bed reactors. Potential applications for the fly ash produced CNTs include use in composite materials.

  20. Fluidized coal combustion

    NASA Technical Reports Server (NTRS)

    Moynihan, P. I.; Young, D. L.

    1979-01-01

    Fluidized-bed coal combustion process, in which pulverized coal and limestone are burned in presence of forced air, may lead to efficient, reliable boilers with low sulfur dioxide and nitrogen dioxide emissions.

  1. Effect of bed pressure drop on performance of a CFB boiler

    SciTech Connect

    Hairui Yang; Hai Zhang; Shi Yang; Guangxi Yue; Jun Su; Zhiping Fu

    2009-05-15

    The effect of bed pressure drop and bed inventory on the performances of a circulating fluidized bed (CFB) boiler was studied. By using the state specification design theory, the fluidization state of the gas-solids flow in the furnace of conventional CFB boilers was reconstructed to operate at a much lower bed pressure drop by reducing bed inventory and control bed quality. Through theoretical analysis, it was suggested that there would exist a theoretical optimal value of bed pressure drop, around which the boiler operation can achieve the maximal combustion efficiency and with significant reduction of the wear of the heating surface and fan energy consumption. The analysis was validated by field tests carried out in a 75 t/h CFB boiler. At full boiler load, when bed pressure drop was reduced from 7.3 to 3.2 kPa, the height of the dense zone in the lower furnace decreased, but the solid suspension density profile in the upper furnace and solid flow rate were barely influenced. Consequently, the average heat transfer coefficient in the furnace was kept nearly the same and the furnace temperature increment was less than 17{sup o}C. It was also found that the carbon content in the fly ash decreased first with decreasing bed pressure drop and then increased with further increasing bed pressure drop. The turning point with minimal carbon content was referred to as the point with optimal bed pressure drop. For this boiler, at the optimum point the bed pressure was around 5.7 kPa with the overall excess air ratio of 1.06. When the boiler was operated around this optimal point, not only the combustion efficiency was improved, but also fan energy consumption and wear of heating surface were reduced. 23 refs., 6 figs., 4 tabs.

  2. Fly ash quality and utilization

    SciTech Connect

    Barta, L.E.; Lachner, L.; Wenzel, G.B.; Beer, M.J.

    1995-12-01

    The quality of fly ash is of considerable importance to fly ash utilizers. The fly ash puzzolanic activity is one of the most important properties that determines the role of fly ash as a binding agent in the cementing process. The puzzolanic activity, however is a function of fly ash particle size and chemical composition. These parameters are closely related to the process of fly ash formation in pulverized coal fired furnaces. In turn, it is essential to understand the transformation of mineral matter during coal combustion. Due to the particle-to-particle variation of coal properties and the random coalescence of mineral particles, the properties of fly ash particles e.g. size, SiO{sub 2} content, viscosity can change considerably from particle to particle. These variations can be described by the use of the probability theory. Since the mean values of these randomly changing parameters are not sufficient to describe the behavior of individual fly ash particles during the formation of concrete, therefore it is necessary to investigate the distribution of these variables. Examples of these variations were examined by the Computer Controlled Scanning Electron Microscopy (CCSEM) for particle size and chemical composition for Texas lignite and Eagel Butte mineral matter and fly ash. The effect of combustion on the variations of these properties for both the fly ash and mineral matter were studied by using a laminar flow reactor. It is shown in our paper, that there are significant variations (about 40-50% around the mean values) of the above-listed properties for both coal samples. By comparing the particle size and chemical composition distributions of the mineral matter and fly ash, it was possible to conclude that for the Texas lignite mineral matter, the combustion did not effect significantly the distribution of these properties, however, for the Eagel Butte coal the combustion had a major impact on these mineral matter parameters.

  3. Fluidized bed injection assembly for coal gasification

    DOEpatents

    Cherish, Peter; Salvador, Louis A.

    1981-01-01

    A coaxial feed system for fluidized bed coal gasification processes including an inner tube for injecting particulate combustibles into a transport gas, an inner annulus about the inner tube for injecting an oxidizing gas, and an outer annulus about the inner annulus for transporting a fluidizing and cooling gas. The combustibles and oxidizing gas are discharged vertically upward directly into the combustion jet, and the fluidizing and cooling gas is discharged in a downward radial direction into the bed below the combustion jet.

  4. Post Combustion Test Bed Development

    SciTech Connect

    Cabe, James E.; King, Dale A.; Freeman, Charles J.

    2011-12-30

    Pacific Northwest National Laboratory (PNNL) assessment methodology and slip-stream testing platform enables the comprehensive early-stage evaluation of carbon capture solvents and sorbents utilizing a breadth of laboratory experimental capability as well as a testing platform at a nearby 600 MW pulverized coal-fired power plant.

  5. Structural and thermal behavior of coal combustion and gasification by-products

    SciTech Connect

    Valimbe, P.S.; Malhotra, V.M.; Banerjee, D.

    1995-12-31

    We have initiated studies which attempt to convert coal combustion and coal gasification by-products into high-value composite materials. However, before conversion strategies can be put in place, the raw materials must be characterized. Therefore, we undertook systematic microscopy and spectroscopy measurements on PCC fly ash, FBC fly ash, FBC spent bed ash, and scrubber sludge. Our spectroscopic results indicate that the scrubber sludge is mainly composed of a gypsum-like phase whose lattice structure does not exactly match either conventional gypsum or hannebachite. SEM images indicate that unlike PCC fly ash particles, which are mainly spherical, the FBC fly ash and FBC spent bed ash particles are irregularly shaped and show considerable fusion. FBC fly ashes are mainly composed of anhydrite, lime, portlandite, calcite, hematite, magnetite and various glass phases. The DTA and DSC data suggest that the PCC fly ash is thermally stable up to 1100{degrees}C. However, this is not the case for FBC residue.

  6. [Effects of sulphur compounds on the volatile characteristics of heavy metals in fly ash from the MSW and sewage sludge co-combustion plant during the disposal process with higher temperature].

    PubMed

    Liu, Jing-Yong; Sun, Shui-Yu

    2012-11-01

    Fly ash sample was collected from a MSW co-combustion with sewage sludge plant and the volatilization of heavy metals Pb, Cd, Cu and Zn was investigated before and after the water washing of fly ash, meanwhile, the influence of adding different sulphur compounds (S, NaS, Na2 SO3, Na2 SO4) on the volatilization of heavy metals was studied. The results showed that the contents of Zn, Pb and Mn were high, the Ni content was low and the Cd content reached 29.4 mg x kg(1). The contents of Pb, Cu, Zn increased, while that of Cd reduced in the fly ash after water washing. TG-DTG curves of fly ash showed highest weight loss in ranges of 579-732 degrees C and 949-1 200 degrees C, with 690 degrees C and 1 154 degrees C as the inflection point temperatures. The volatilization of different heavy metals showed great difference in the volatilization rate, following the order of Pb > Cd > Zn > Cu, in which the volatilization rate of Pb was more than 80% and that of Cu was less than 30%. After water washing, the volatilization of different heavy metals showed great difference in the volatilization rate, with the order of Zn > Pb > Cd > Cu, in which the volatilization rate of Zn was more than 20%. With the pretreatment of adding Na2 SO3 and Na2 SO4, the evaporation rates of heavy metals (Cu, Pb, Zn, Cd) were significantly decreased. After adding S, the evaporation rate of Zn was reduced, whereas the addition of Na2S reduced the evaporation rates of Cd and Zn. The evaporation rates of the four heavy metals were all reduced after adding Na2S in the washed fly ash. The evaporation rates of Cu and Zn were reduced with addition of S and Na2SO3 and the evaporation rate of Cd was reduced by adding the four sulfides. The results can provide a basis for the harmless disposal and maximized resource utilization and recycling of fly ash.

  7. Formation and use of coal combustion residues from three types of power plants burning Illinois coals

    USGS Publications Warehouse

    Demir, I.; Hughes, R.E.; DeMaris, P.J.

    2001-01-01

    Coal, ash, and limestone samples from a fluidized bed combustion (FBC) plant, a pulverized coal combustion (PC) plant, and a cyclone (CYC) plant in Illinois were analyzed to determine the combustion behavior of mineral matter, and to propose beneficial uses for the power plant ashes. Pyrite and marcasite in coal were converted during combustion to glass, hematite and magnetite. Calcite was converted to lime and anhydrite. The clay minerals were altered to mullite and glass. Quartz was partially altered to glass. Trace elements in coal were partially mobilized during combustion and, as a result, emitted into the atmosphere or adsorbed on fly ash or on hardware on the cool side of the power plants. Overall, the mobilities of 15 trace elements investigated were lower at the FBC plant than at the other plants. Only F and Mn at the FBC plant, F, Hg, and Se at the PC plant and Be, F, Hg, and Se at the CYC plant had over 50% of their concentrations mobilized. Se and Ge could be commercially recovered from some of the combustion ashes. The FBC ashes could be used as acid neutralizing agents in agriculture and waste treatment, and to produce sulfate fertilizers, gypsum wall boards, concrete, and cement. The PC and CYC fly ashes can potentially be used in the production of cement, concrete, ceramics, and zeolites. The PC and CYC bottom ashes could be used in stabilized road bases, as frits in roof shingles, and perhaps in manufacturing amber glass. ?? 2001 Elsevier Science Ltd. All rights reserved.

  8. A STUDY OF THE EFFECTS OF POST-COMBUSTION AMMONIA INJECTION ON FLY ASH QUALITY: CHARACTERIZATION OF AMMONIA RELEASE FROM CONCRETE AND MORTARS CONTAINING FLY ASH AS A POZZOLANIC ADMIXTURE

    SciTech Connect

    Robert F. Rathbone; Thomas L. Robl

    2001-04-11

    Work completed in this reporting period focused on finalization of the Work and Management Plan, sample acquisition and analysis, evaluation of ammonia measurement methods, and measurement of ammonia loss from mortar. All fly ash samples have been acquired and analyzed for chemical composition and particle fineness. Three non-ammoniated fly ash samples were obtained from power plants that do not inject ammonia for NOx or particulate control, while three ammoniated fly ashes originate from plants that inject ammonia into the flue gas. The fly ash sources were selected based on their marketability as concrete admixtures and ammonia content. Coarse and fine aggregates for mortar and concrete testing have also been secured and have been thoroughly characterized using ASTM methods. Methodologies for the measurement of ammonia in the gaseous and aqueous phase have been carefully considered in the context of their suitability for use in this project. These include ammonia detection tubes, carbon impregnated with sulfuric acid (CISA) tubes, titration, and electrochemical methods. It was concluded that each of these methods is potentially useful for different aspects of the project, depending on the phase and concentration of ammonia to be measured. Preparation of fly ash-containing mortars both with and without ammonia indicated that the ammonia has no significant influence on compressive strength. Finally, measurement of ammonia loss from mortar has begun and the results of several of these experiments are included herein. It has been found that, under the laboratory curing conditions devised, ammonia release from mortar occurs at a relatively rapid rate in the first 24 hours, proceeded by a much slower, essentially linear rate. Furthermore, at the end of the three-week experiments, it was calculated that greater than 80% of the initial ammonia concentration remained within the mortar.

  9. A STUDY OF THE EFFECTS OF POST-COMBUSTION AMMONIA INJECTION ON FLY ASH QUALITY: CHARACTERIZATION OF AMMONIA RELEASE FROM CONCRETE AND MORTARS CONTAINING FLY ASH AS A POZZOLANIC ADMIXTURE

    SciTech Connect

    Robert F. Rathbone; Thomas L. Robl

    2002-10-30

    The Clean Air Act Amendments of 1990 require large reductions in emissions of NO{sub x} from coal-fired electric utility boilers. This will necessitate the use of ammonia injection, such as in selective catalytic reduction (SCR), in many power plants, resulting in the deposition of ammonia on the fly ash. The presence of ammonia could create a major barrier to fly ash utilization in concrete because of odor concerns. Although there have been limited studies of ammonia emission from concrete, little is known about the quantity of ammonia emitted during mixing and curing, and the kinetics of ammonia release. This is manifested as widely varying opinions within the concrete and ash marketing industry regarding the maximum acceptable levels of ammonia in fly ash. Therefore, practical guidelines for using ammoniated fly ash are needed in advance of the installation of many more SCR systems. The goal of this project was to develop practical guidelines for the handling and utilization of ammoniated fly ash in concrete, in order to prevent a decrease in the use of fly ash for this application. The objective was to determine the amount of ammonia that is released, over the short- and long-term, from concrete that contains ammoniated fly ash. The technical approach in this project was to measure the release of ammonia from mortar and concrete during mixing, placement, and curing. Work initially focused on laboratory mortar experiments to develop fundamental data on ammonia diffusion characteristics. Larger-scale laboratory experiments were then conducted to study the emission of ammonia from concrete containing ammoniated fly ash. The final phase comprised monitoring ammonia emissions from large concrete slabs. The data indicated that, on average, 15% of the initial ammonia was lost from concrete during 40 minutes of mixing, depending on the mix proportions and batch size. Long-term experiments indicated that ammonia diffusion from concrete was relatively slow, with greater

  10. Numerical analysis of the process of combustion and gasification of the polydisperse coke residue of high-ash coal under pressure in a fluidized bed

    SciTech Connect

    A.Y. Maistrenko; V.P. Patskov; A.I. Topal; T.V. Patskova

    2007-09-15

    A numerical analysis of the process of 'wet' gasification of high-ash coal under pressure in a low-temperature fluidized bed has been performed. The applicability of the previously developed computational model, algorithm, and program for the case under consideration has been noted. The presence of 'hot spots' (short-time local heatings) at different points of the bed has been confirmed.

  11. Morphological and biochemical changes in Azadirachta indica from coal combustion fly ash dumping site from a thermal power plant in Delhi, India.

    PubMed

    Qadir, Sami Ullah; Raja, Vaseem; Siddiqui, Weqar A

    2016-07-01

    The foliar and biochemical traits of Azadirachta indica A. Juss from fly ash (FA) dumping site in Badarpur thermal power plant (BTPP) New Delhi, India was studied. Three different experimental sites were selected at different distances from the thermal power plant. Ambient suspended particulate matter (SPM) and plant responses such as leaf pigments (chlorophyll a, chlorophyll b, and carotenoids), total chlorophyll, net photosynthetic rate, stomatal index (SI), stomatal conductance (SC), intercellular carbon dioxide concentration [CO2]i, net photosynthetic rate (NPR), nitrogen, nitrate, nitrate reductase activity, proline, protein, reducing sugar and sulphur content were measured. Considerable reduction in pigments (chlorophyll a, chlorophyll b and carotenoids), and total chlorophyll was observed at fly ash dumping site. Fly ash stress revealed the inhibitory effect on Nitrate reductase activity (NRA), Nitrate, soluble protein, and reducing sugar content, whereas stimulatory effect was found for the stomatal index, nitrogen, proline, antioxidants and sulphur content in the leaves. Under fly ash stress, stomatal conductance was low, leading to declining in photosynthetic rate and increase in the internal CO2 concentration of leaf. Single leaf area (SLA), leaf length and leaf width also showed a declining trend from control to the polluted site. Antioxidant enzymes increased in leaves reflecting stress and extenuation of reactive oxygen species (ROS).

  12. Characterization study and five-cycle tests in a fixed-bed reactor of titania-supported nickel oxide as oxygen carriers for the chemical-looping combustion of methane.

    PubMed

    Corbella, Beatriz M; de Diego, Luis F; García-Labiano, Francisco; Adánez, Juan; Palaciost, José M

    2005-08-01

    Recent investigations have shown that in the combustion of carbonaceous compounds CO2 and NOx emissions to the atmosphere can be substantially reduced by using a two stage chemical-looping process. In this process, the reduction stage is undertaken in a first reactor in which the framework oxygen of a reducible inorganic oxide is used, instead of the usual atmospheric oxygen, for the combustion of a carbonaceous compound, for instance, methane. The outlet gas from this reactor is mostly composed of CO2 and steam as reaction products and further separation of these two components can be carried out easily by simple condensation of steam. Then, the oxygen carrier found in a reduced state is transported to a second reactor in which carrier regeneration with air takes place at relatively low temperatures, consequently preventing the formation of thermal NOx. Afterward, the regenerated carrier is carried to the first reactor to reinitiate a new cycle and so on for a number of repetitive cycles, while the carrier is able to withstand the severe chemical and thermal stresses involved in every cycle. In this paper, the performance of titania-supported nickel oxides has been investigated in a fixed-bed reactor as oxygen carriers for chemical-looping combustion of methane. Samples with different nickel oxide contents were prepared by successive incipient wet impregnations, and their performance as oxygen carriers was investigated at 900 degrees C and atmospheric pressure in five-cycle fixed-bed reactor tests using pure methane and pure air for the respective reduction and regeneration stages. The evolution of the outlet gas composition in each stage was followed by gas chromatography, and the involved chemical, structural, and textural changes of the carrier in the reactor bed were studied by using different characterization techniques. From the study, it is deduced that the reactivity of these nickel-based oxygen carriers is in the two involved stages and almost independent

  13. Design and assembly of a catalyst bed gas generator for the catalytic decomposition of high concentration hydrogen peroxide propellants and the catalytic combustion of hydrocarbon/air mixtures

    NASA Technical Reports Server (NTRS)

    Lohner, Kevin A. (Inventor); Mays, Jeffrey A. (Inventor); Sevener, Kathleen M. (Inventor)

    2004-01-01

    A method for designing and assembling a high performance catalyst bed gas generator for use in decomposing propellants, particularly hydrogen peroxide propellants, for use in target, space, and on-orbit propulsion systems and low-emission terrestrial power and gas generation. The gas generator utilizes a sectioned catalyst bed system, and incorporates a robust, high temperature mixed metal oxide catalyst. The gas generator requires no special preheat apparatus or special sequencing to meet start-up requirements, enabling a fast overall response time. The high performance catalyst bed gas generator system has consistently demonstrated high decomposition efficiency, extremely low decomposition roughness, and long operating life on multiple test articles.

  14. Flying wings / flying fuselages

    NASA Technical Reports Server (NTRS)

    Wood, Richard M.; Bauer, Steven X. S.

    2001-01-01

    The present paper has documented the historical relationships between various classes of all lifting vehicles, which includes the flying wing, all wing, tailless, lifting body, and lifting fuselage. The diversity in vehicle focus was to ensure that all vehicle types that map have contributed to or been influenced by the development of the classical flying wing concept was investigated. The paper has provided context and perspective for present and future aircraft design studies that may employ the all lifting vehicle concept. The paper also demonstrated the benefit of developing an understanding of the past in order to obtain the required knowledge to create future concepts with significantly improved aerodynamic performance.

  15. A STUDY OF THE EFFECTS OF POST-COMBUSTION AMMONIA INJECTION ON FLY ASH QUALITY: CHARACTERIZATION OF AMMONIA RELEASE FROM CONCRETE AND MORTARS CONTAINING FLY ASH AS A POZZOLANIC ADMIXTURE

    SciTech Connect

    Robert F. Rathbone; Thomas L. Robl

    2001-10-11

    Work completed in this reporting period focused on the measurement of the rate of ammonia loss from mortar and concrete, and the measurement of ammonia gas in the air above the materials immediately after placement. The majority of mortar experiments have been completed, and testing has begun on concrete. The mortar experiments indicate that the rate of ammonia loss is greater in mortars prepared using a higher water content and water:cement (W:C) ratio, although the higher rate is primarily observed within the first 2 days, after which the loss rates are nearly the same. The source of low-calcium (Class F) fly ash exerted a negligible influence on the loss rate. However, mortar prepared using a higher-calcium fly ash evolved ammonia at a slightly slower rate than the Class F ash mortars. The data also indicate that an increase in ventilation increases the ammonia loss rate from mortar, and suggest that a well-ventilated space could substantially increase the loss of ammonia from mortar and, by inference, a concrete slab. Analysis of ammonia concentrations in the air above freshly-placed mortars in an enclosed space indicate that the fly ash ammonia concentration should not exceed 100 mg N/kg ash in confined space applications. For most other applications with some ventilation the maximum acceptable concentration would be approximately 200 mg/kg. Early results from experiments on concrete suggest that, under similar conditions, ammonia diffusion from concrete occurs at a higher rate than in mortar. In addition, increasing the slump of concrete through the use of chemical admixtures has only a minor effect on the ammonia loss rate.

  16. A STUDY OF THE EFFECTS OF POST-COMBUSTION AMMONIA INJECTION ON FLY ASH QUALITY: CHARACTERIZATION OF AMMONIA RELEASE FROM CONCRETE AND MORTARS CONTAINING FLY ASH AS A POZZOLANIC ADMIXTURE

    SciTech Connect

    Robert F. Rathbone; Thomas L. Robl

    2002-04-11

    Work completed in this reporting period focused primarily on continuing measurements of the rate of ammonia loss from concrete, and the measurement of ammonia gas in the air above concrete and flowable fill immediately after placement. Concrete slabs were prepared to monitor the loss of ammonia during mixing, the concentration in the airspace above the slabs soon after placement, and the total quantity of ammonia evolved over a longer time period. Variables tested include temperature, ventilation rate, water:cementitious (W:C) ratio, and fly ash source. Short-term data indicate that for concrete placed in areas with poor air ventilation the fly ash NH{sub 3} concentration should not exceed about 90 to 145 mg/kg ash, depending on the water:cement ratio and the fly ash replacement rate, if a concentration of 10 ppm NH{sub 3} in the air is assumed to be the maximum acceptable level. Longer-term experiments showed that the ammonia loss rate is dependent on ammonia source (that is ammoniated ash vs. non-ammoniated ash with ammonia added to the water), and is also dependent on W:C ratio and temperature. Experiments were also conducted to study the loss of ammonia from fresh concrete during mixing. It was found that a high water:cementitious mix lost a greater percentage of ammonia than a low W:C mix, with a medium W:C mix losing an amount intermediate between these two. However, a larger batch size resulted in a smaller percentage of ammonia lost. The data suggest that a significant quantity of ammonia could be lost from Ready Mix concrete during transit, depending on the transit time, batch size, and mix proportions.

  17. Fast fluidized bed steam generator

    DOEpatents

    Bryers, Richard W.; Taylor, Thomas E.

    1980-01-01

    A steam generator in which a high-velocity, combustion-supporting gas is passed through a bed of particulate material to provide a fluidized bed having a dense-phase portion and an entrained-phase portion for the combustion of fuel material. A first set of heat transfer elements connected to a steam drum is vertically disposed above the dense-phase fluidized bed to form a first flow circuit for heat transfer fluid which is heated primarily by the entrained-phase fluidized bed. A second set of heat transfer elements connected to the steam drum and forming the wall structure of the furnace provides a second flow circuit for the heat transfer fluid, the lower portion of which is heated by the dense-phase fluidized bed and the upper portion by the entrained-phase fluidized bed.

  18. Fluidized bed boiler feed system

    DOEpatents

    Jones, Brian C.

    1981-01-01

    A fluidized bed boiler feed system for the combustion of pulverized coal. Coal is first screened to separate large from small particles. Large particles of coal are fed directly to the top of the fluidized bed while fine particles are first mixed with recycled char, preheated, and then fed into the interior of the fluidized bed to promote char burnout and to avoid elutriation and carryover.

  19. Using fly ash for construction

    SciTech Connect

    Valenti, M.

    1995-05-01

    Each year electrical utilities generate 80 million tons of fly ash, primarily from coal combustion. Typically, utilities dispose of fly ash by hauling it to landfills, but that is changing because of the increasing cost of landfilling, as well as environmental regulations. Now, the Electric Power Research Institute (EPRI), in Palo Alto, Calif., its member utilities, and manufacturers of building materials are finding ways of turning this energy byproduct into the building blocks of roads and structures by converting fly ash into construction materials. Some of these materials include concrete and autoclaved cellular concrete (ACC, also known as aerated concrete), flowable fill, and light-weight aggregate. EPRI is also exploring uses for fly ash other than in construction materials. One of the more high-end uses for the material is in metal matrix composites. In this application, fly ash is mixed with softer metals, such as aluminum and magnesium, to strengthen them, while retaining their lighter weight.

  20. Can Chemical Looping Combustion Use CFB Technology?

    SciTech Connect

    Gamwo, I.K.

    2006-11-01

    Circulating Fluidized Bed (CFB) technology has demonstrated an unparalleled ability to achieve low SO2 and NOx emissions for coal-fired power plants without CO2 capture. Chemical Looping combustion (CLC) is a novel fuel combustion technology which appears as a leading candidate in terms of competitiveness for CO2 removal from flue gas. This presentaion deals with the adaptation of circulating fluidized bed technology to Chemical looping combustion

  1. Bed Bugs

    EPA Pesticide Factsheets

    Prevent, identify, and treat bed bug infestations using EPA’s step-by-step guides, based on IPM principles. Find pesticides approved for bed bug control, check out the information clearinghouse, and dispel bed bug myths.

  2. Second generation pressurized fluidized-bed combustion (PFBC) research and development, Phase 2 --- Task 4, carbonizer testing. Volume 2, Data reconciliation

    SciTech Connect

    Froehlich, R.; Robertson, A.; Vanhook, J.; Goyal, A.; Rehmat, A.; Newby, R.

    1994-11-01

    During the period beginning November 1991 and ending September 1992, a series of tests were conducted at Foster Wheeler Development Corporation in a fluidized-bed coal carbonizer to determine its performance characteristics. The carbonizer was operated for 533 hours in a jetting fluidized-bed configuration during which 36 set points (steady-state periods) were achieved. Extensive data were collected on the feed and product stream compositions, heating values, temperatures, and flow rates. With these data, elemental and energy balances were computed to evaluate and confirm accuracy of the data. The carbonizer data were not as self-consistent as could be desired (balance closure imperfection). A software package developed by Science Ventures, Inc., of California, called BALAID, was used to reconcile the carbonizer data; the details of the reconciliation have been given in Volume 1 of this report. The reconciled data for the carbonizer were rigorously analyzed, correlations were developed, and the model was updated accordingly. The model was then used in simulating each of the 36 steady-state periods achieved in the pilot plant. The details are given in this Volume one. This Volume 2 provides details of the carbonizer data reconciliation.

  3. Second generation pressurized fluidized-bed combustion (PFBC) research and development, Phase 2 -- Task 4, carbonizer testing. Volume 1, Test results

    SciTech Connect

    Froehlich, R.; Robertson, A.; Vanhook, J.; Goyal, A.; Rehmat, A.; Newby, R.

    1994-11-01

    During the period beginning November 1991 and ending September 1992, a series of tests were conducted at Foster Wheeler Development Corporation in a fluidized-bed coal carbonizer to determine its performance characteristics. The carbonizer was operated for 533 hours in a jetting fluidized-bed configuration during which 36 set points (steady-state periods) were achieved. Extensive data were collected on the feed and product stream compositions, heating values, temperatures, and flow rates. With these data, elemental and energy balances were computed to evaluate and confirm accuracy of the data. The carbonizer data were not as self-consistent as could be desired (balance closure imperfection). A software package developed by Science Ventures, Inc., of California, called BALAID, was used to reconcile the carbonizer data; the details of the reconciliation have been given in Volume 1 of this report. The reconciled data for the carbonizer were rigorously analyzed, correlations were developed, and the model was updated accordingly. The model was then used in simulating each of the 36 steady-state periods achieved in the pilot plant. The details are given in this Volume of the report.

  4. Experiments on chemical looping combustion of coal with a NiO based oxygen carrier

    SciTech Connect

    Shen, Laihong; Wu, Jiahua; Xiao, Jun

    2009-03-15

    A chemical looping combustion process for coal using interconnected fluidized beds with inherent separation of CO{sub 2} is proposed in this paper. The configuration comprises a high velocity fluidized bed as an air reactor, a cyclone, and a spout-fluid bed as a fuel reactor. The high velocity fluidized bed is directly connected to the spout-fluid bed through the cyclone. Gas composition of both fuel reactor and air reactor, carbon content of fly ash in the fuel reactor, carbon conversion efficiency and CO{sub 2} capture efficiency were investigated experimentally. The results showed that coal gasification was the main factor which controlled the contents of CO and CH{sub 4} concentrations in the flue gas of the fuel reactor, carbon conversion efficiency in the process of chemical looping combustion of coal with NiO-based oxygen carrier in the interconnected fluidized beds. Carbon conversion efficiency reached only 92.8% even when the fuel reactor temperature was high up to 970 C. There was an inherent carbon loss in the process of chemical looping combustion of coal in the interconnected fluidized beds. The inherent carbon loss was due to an easy elutriation of fine char particles from the freeboard of the spout-fluid bed, which was inevitable in this kind of fluidized bed reactor. Further improvement of carbon conversion efficiency could be achieved by means of a circulation of fine particles elutriation into the spout-fluid bed or the high velocity fluidized bed. CO{sub 2} capture efficiency reached to its equilibrium of 80% at the fuel reactor temperature of 960 C. The inherent loss of CO{sub 2} capture efficiency was due to bypassing of gases from the fuel reactor to the air reactor, and the product of residual char burnt with air in the air reactor. Further experiments should be performed for a relatively long-time period to investigate the effects of ash and sulfur in coal on the reactivity of nickel-based oxygen carrier in the continuous CLC reactor

  5. Pressurized fluidized bed combustion second-generation system research and development. Technical progress for Phase 2 and Phase 3, October 1, 1997--September 30, 1998

    SciTech Connect

    Robertson, A.; Horazak, D.; Newby, R.; Rehmat, A.; White, J.

    1998-10-01

    When DOE funds were exhausted in March 1995, all Phase 2 activities were placed on hold. In February 1996 a detailed cost estimate was submitted to the DOE for completing the two remaining Phase 2 Multi Annular Swirl Burner (MASB) topping combustor test burns; in August 1996 release was received from METC to proceed with these tests. The first test (Test Campaign No.3) will be conducted to: (1) test the MASB at proposed demonstration plant full to minimum loading operating conditions; (2) identify the lower oxygen limit of the MASB; and (3) demonstrate natural gas to carbonizer fuel gas switching. The Livingston Phase 3 Pilot Plant was last operated under contract DE-AC21-86MC21023 in September 1995 for seven days in an integrated carbonizer-CPFBC configuration. In May, 1996, the pilot plant was transferred to Contract DE-AC22-95PC95143 to allow testing in support of the High Performance Power Systems (HIPPS) Program. The HIPPS Program required modifications to the pilot plant and the following changes were incorporated: (1) installation of a dense phase transport system for loading pulverized coal into the feed system lock hopper directly from a pneumatic transport truck; (2) removal of the char transfer pipe between the char collecting hopper and the CPFBC to allow carbonizer only operation; (3) installation of a lock hopper directly under the char collecting hopper to facilitate char removal from the process, the hopper vent gases exhaust to the carbonizer baghouse filter and the depressured char is transferred via nitrogen to the CPFBC baghouse for dumping into drums; (4) removal of the carbonizer cyclone and top of bed overflow drain line; all material elutriated from the carbonizer bed will thus be removed by the 22-element Westinghouse ceramic candle filter; (5) replacement of the carbonizer continuous bottom bed drain (screw feeder) with a batch-type drain removal system; and (6) installation of a mass spectrometer that draws sample gas via a steam jacketed

  6. Combustion characteristics of husk charcoal

    SciTech Connect

    Shimizu, H.; Kimura, T.; Nishiyama, Y.; Terui, T.

    1984-07-01

    This paper analyzes the factors involved in the extraordinary temperature generation in husk combustion furnaces, and investigates methods of protecting furnaces from heat damage. The combustion characteristics of fixed carbon in rice husks are examined in relation to the air flow rate using different husk charcoals. The theoretical flame temperature in a practical bed was determined from the combustion propagation velocity. It is determined that deviation from the regression line relating the combustion propagation velocity with the specific air flow rate showed a slight correlation with the bulk density of the charcoal samples used.

  7. Bed bugs.

    PubMed

    Foulke, Galen T; Anderson, Bryan E

    2014-09-01

    The term bed bug is applied to 2 species of genus Cimex: lectularius describes the common or temperate bed bug, and hemipterus its tropical cousin. Cimex lectularius is aptly named; its genus and species derive from the Latin words for bug and bed, respectively. Though the tiny pest is receiving increased public attention and scrutiny, the bed bug is hardly a new problem.

  8. The effect of staging of reburning fuel to reduce NO{sub x} and N{sub 2}O levels during fluidized bed coal combustion

    SciTech Connect

    Gulyurtlu, I.K.; Bordalo, C.; Cabrita, I.A.

    1995-12-31

    Studies have been undertaken with the objective of using biomass waste as a reburning fuel which could be introduced to the combustor at different heights. The staging of the secondary air was also implemented as a further measure for controlling the emissions of NO{sub x} and N{sub 2}O. The biomass waste contains very high volatile content and very small amounts of fuel-N. Upon release, these volatiles are generally released as NH{sub y} compounds rather than HCN or other CN groups. Consequently, the reactions leading to the formation of both N{sub 2}O and NO{sub x} appear to be suppressed and the presence of high levels of hydrocarbon radicals originating from volatiles consequently gives rise to a reduction in NO{sub x} amounts. Experimental results obtained suggest that the N{sub 2}O amounts could be lowered by about 20 to 40% and NO{sub x} values were found to be brought down below 250 ppm. With only coal combustion the levels of NO{sub x} and N{sub 2}O were measured to be about 400 and 100 ppm respectively. No adverse effects on SO{sub 2} capture were observed.

  9. Comparison of different natural sorbents for removing CO{sub 2} from combustion gases, as studied in a bench-scale fluidized bed

    SciTech Connect

    M. Ives; R.C. Mundy; P.S. Fennell; J.F. Davidson; J.S. Dennis; A.N. Hayhurst

    2008-11-15

    The reaction of CO{sub 2} with porous particles of CaO for chicken eggshells, mussel shells, and limestone. The reaction is a promising way of removing CO{sub 2}, e.g., from the exhaust of a power station, so that a pure stream of CO{sub 2} can subsequently be produced for sequestration by calcining (roasting) the solid CaCO{sub 3}. The reverse of the reaction regenerates the sorbent, which can thus be used cyclically. The reaction were investigated using a small electrically heated bed of sand at about 750{degree}C, fluidized by N{sub 2}. Typically, a sample (about 2 g) of cleaned calcareous material (sieved to about 600 {mu}m) was added to the hot bed, and the CO{sub 2} produced was measured, while the material was fully calcined. Next, enough CO{sub 2} was added to the fluidizing N{sub 2} to raise (CO{sub 2}) to above the value for equilibrium; thus, the CaO was carbonated. This forward step is shown to exhibit an apparent final conversion, the carrying capacity of the sorbent, below unity. This carrying capacity reduces after several cycles of calcination and carbonation, because blockage of pores denies access of CO{sub 2} to part of the CaO. After several such cycles, particles were removed from the reactor, either in their partially carbonated or fully calcined states, for studies using gas adsorption analysis, X-ray diffraction, and mercury porosimetry. Interestingly, it was found for all three sorbents that the carrying capacity of CaO for CO{sub 2} degraded at a similar rate. The carrying capacity was roughly proportional to the volume of pores narrower than about 100 nm, as measured by Barrett-Joyner-Halenda (BJH) gas adsorption analysis. Evidently, these narrow pores contain both the surface area for CO{sub 2} to absorb and the empty volume to accommodate the product, CaCO{sub 3}. The resistance of eggshells to attrition was broadly comparable to that of Purbeck (U.K.) limestone. 24 refs., 8 figs., 2 tabs.

  10. Pneumatic conveying of coal and coal-limestone mixtures as applied to atmospheric fluidized-bed combustion. [Effects of moisture, velocity, particle size

    SciTech Connect

    Daw, C. S.; Thomas, J. F.

    1982-01-01

    Pneumatic conveying experiments with coal and coal-limestone mixtures were performed on a conveying system designed to represent the feed lines in the Tennessee Valley Authority 20 MW atmospheric fluidized bed combustor. The experimental conditions were chosen to cover the anticipated combustor operating ranges. The results have led to a fundamental understanding of the operating limits associated with coal surface moisture, air velocity, coal and limestone fines, solids to air ratio, and limestone to coal ratio. Coal surface moisture was found to be the most important parameter affecting handling and transport. Specific upper limits for surface moisture were established. It was demonstrated that addition of dry limestone can reduce the conveying problems associated with wet coal. The air velocities causing saltation and surge flow were determined for a variety of conveying conditions. These velocities were related qualitatively to solids to air ratio, particle size, and surface moisture. Conveying pressure drop was also measured for a variety of conditions. In the absence of saltation, the horizontal, frictional pressure drop was only a function of the solids to air ratio and the air flow conditions. Comparison of the ORNL pressure drop data with the results of other investigators had led to the conclusion that there are two basic modes of flow in dilute-phase conveying; a primarily viscous mode and a primarily inertial mode. A general pressure drop model has been developed for the inertial mode.

  11. Starting procedure for internal combustion vessels

    DOEpatents

    Harris, Harry A.

    1978-09-26

    A vertical vessel, having a low bed of broken material, having included combustible material, is initially ignited by a plurality of ignitors spaced over the surface of the bed, by adding fresh, broken material onto the bed to buildup the bed to its operating depth and then passing a combustible mixture of gas upwardly through the material, at a rate to prevent back-firing of the gas, while air and recycled gas is passed through the bed to thereby heat the material and commence the desired laterally uniform combustion in the bed. The procedure permits precise control of the air and gaseous fuel mixtures and material rates, and permits the use of the process equipment designed for continuous operation of the vessel.

  12. Modeling of fluidized-bed combustion of coal: Phase II, final reports. Volume VI. FBC-Data Base-Management-System (FBC-DBMS) development

    SciTech Connect

    Louis, J.F.; Tung, S.E.

    1980-10-01

    The primary goal of the Fluidized Bed Combustor Data Base, (FBCDB), situated in MIT's Energy laboratory, is to establish a data repository for the express use of designers and research personnel involved in FBC development. DBMS is a software that provides an efficient way of storing, retrieving, updating and manipulating data using an English-like query language. It is anticipated that the FBCDB would play an active and a direct role in the development of FBC technology as well as in the FBC commercial application. After some in-house experience and after a careful and extensive review of commercially available database systems, it was determined that the Model 204 DBMS by Computer Corporation of America was the most suitable to our needs. The setup of a prototype in-house database also allowed us to investigate and understand fully the particular problems involved in coordinating FBC development with a DBMS. Various difficult aspects were encountered and solutions had been sought. For instance, we found that it was necessary to rename the variables to avoid repetition as well as to increase usefulness of our database and, hence, we had designed a classification system for which variables were classified under category to achieve standardization of variable names. The primary content of FBCDB is a collection of data points defined by the value of a number of specific FBC variables. A user may interactively access the database from a computer terminal at any location, retrieve, examine, and manipulate the data as well as produce tables or graphs of the results.

  13. Fly Ash and Mercury Oxidation/Chlorination Reactions

    SciTech Connect

    Sukh Sidhu; Patanjali Varanasi

    2008-12-31

    Mercury is a known pollutant that has detrimental effect on human health and environment. The anthropogenic emissions of mercury account for 10 to 30% of worldwide mercury emissions. There is a need to control/reduce anthropogenic mercury emissions. Many mercury control technologies are available but their effectiveness is dependent on the chemical form of mercury, because different chemical forms of mercury have different physical and chemical properties. Mercury leaves the boiler in its elemental form but goes through various transformations in the post-combustion zone. There is a need to understand how fly ash and flue gas composition affect speciation, partitioning, and reactions of mercury under the full range of post-combustion zone conditions. This knowledge can then be used to predict the chemical transformation of mercury (elemental, oxidized or particulate) in the post combustion zone and thus help with the control of mercury emissions from coal-burning power plants. To accomplish this goal present study was conducted using five coal fly ashes. These ashes were characterized and their catalytic activity was compared under selected reaction conditions in a fixed bed reactor. Based on the results from these fly ash experiments, three key components (carbon, iron oxide and calcium oxide) were chosen. These three components were then used to prepare model fly ashes. Silica/alumina was used as a base for these model fly ashes. One, two or three component model fly ashes were then prepared to investigate mercury transformation reactions. The third set of experiments was performed with CuO and CuCl2 catalysts to further understand the mercury oxidation process. Based on the results of these three studies the key components were predicted for different fly ash compositions under variety of flue gas conditions. A fixed bed reactor system was used to conduct this study. In all the experiments, the inlet concentration of Hg0(g) was maintained at 35 {micro}g/m3 using

  14. Multicycle study on chemical-looping combustion of simulated coal gas with a CaSO{sub 4} oxygen carrier in a fluidized bed reactor

    SciTech Connect

    Qilei Song; Rui Xiao; Zhongyi Deng; Wenguang Zheng; Laihong Shen; Jun Xiao

    2008-11-15

    The cyclic test of a CaSO{sub 4}-based oxygen carrier (natural anhydrite) in alternating reducing simulated coal gas and oxidizing conditions was performed at 950{degree}C in a fluidized bed reactor at atmospheric pressure. A high concentration of CO{sub 2} was obtained in the reduction. The H{sub 2} and CO conversions and CO{sub 2} yield increased initially and final decreased significantly. The release of SO{sub 2} and H{sub 2}S during the cyclic test was found to be responsible for the decrease of reactivity of a CaSO{sub 4} oxygen carrier. The oxygen carrier conversion after the reduction reaction decreased gradually in the cyclic test. Through the comparison of mass-based reaction rates as a function of mass conversion at typical cycles, it was also evident that the reactivity of a CaSO{sub 4} oxygen carrier increased for the initial cycles but finally decreased after around 15 cycles. X-ray diffraction analysis revealed that the presence and intensity of the reduction sulfur species was in accordance with the results of gas conversion. The content of CaO was higher than expected, suggesting the formation of SO{sub 2} and H{sub 2}S during the cycles. Surface morphology analysis demonstrates that the natural anhydrite particle surface varied from impervious to porous after the cyclic test. It was also observed that the small grains on the surface of the oxygen carrier sintered in the cyclic tests. Energy-dispersive spectrum analysis also demonstrated the decrease of oxygen intensity after reduction, and CaO became the main component after the 20th oxidation. Pore structure analysis suggested that the particles agglomerated or sintered in the cyclic tests. The possible method for sulfur mitigation is proposed. Finally, some basic consideration on the design criteria of a CLC system for solid fuels using a CaSO{sub 4} oxygen carrier is discussed by the references and provides direction for future work. 49 refs., 10 figs., 5 tabs.

  15. Flying Cars

    NASA Technical Reports Server (NTRS)

    Crow, Steven

    1996-01-01

    Flying cars have nearly mythical appeal to nonpilots, a group that includes almost the whole human race. The appeal resides in the perceived utility of flying cars, vehicles that offer portal-to-portal transportation, yet break the bonds of road and traffic and travel freely through the sky at the drivers will. Part of the appeal is an assumption that flying cars can be as easy to fly as to drive. Flying cars have been part of the dream of aviation since the dawn of powered flight. Glenn Curtiss built, displayed, and maybe even flew a flying car in 1917, the Curtiss Autoplane. Many roadable airplanes were built in the 1930's, like the Waterman Arrowbile and the Fulton Airphibian. Two flying cars came close to production in the early 1950's. Ted Hall built a series of flying cars culminating in the Convaircar, sponsored by Consolidated Vultee, General Motors, and Hertz. Molt Taylor built and certified his Aerocar, and Ford came close to producing them. Three Aerocars are still flyable, two in museums in Seattle and Oshkosh, and the third owned and flown by Ed Sweeny. Flying cars do have problems, which so far have prevented commercial success. An obvious problem is complexity of the vehicle, the infrastructure, or both. Another is the difficulty of matching low power for normal driving with high power in flight. An automobile uses only about 20 hp at traffic speeds, while a personal airplane needs about 160 hp at speeds typical of flight. Many automobile engines can deliver 160 hp, but not for very long. A more subtle issue involves the drag of automobiles and airplanes. A good personal airplane can fly 30 miles per gallon of fuel at 200 mph. A good sports car would need 660 hp at the same speed and would travel only 3 miles per gallon. The difference is drag area, about 4.5 sq ft for the automobile and 1.4 sq ft for the airplane. A flying car better have the drag area of the airplane, not the car!

  16. Char binder for fluidized beds

    DOEpatents

    Borio, Richard W.; Accortt, Joseph I.

    1981-01-01

    An arrangement that utilizes agglomerating coal as a binder to bond coal fines and recycled char into an agglomerate mass that will have suitable retention time when introduced into a fluidized bed 14 for combustion. The simultaneous use of coal for a primary fuel and as a binder effects significant savings in the elimination of non-essential materials and processing steps.

  17. Adsorptive properties of fly ash carbon

    SciTech Connect

    Graham, U.M.; Robl, T.L.; Rathbone, R.F.

    1996-12-31

    The driving force behind the development of this research project has been the increasing concerns about the detrimental effects of high carbon carryover into combustion ash. Without the carbon, combustion ash can be utilized in cement industry avoiding environmental implications in landfill operations. Because the carbon surfaces have been structurally altered while passing through the combustor, including the formation of a macro-porous surface, fly ash carbons, after separation from the ash, may constitute a unique precursor for the production of adsorbents. This paper discusses a novel approach for using fly ash carbons in the cleanup of organic pollutants.

  18. Contribution of Aluminas and Aluminosilicates to the Formation of PCDD/Fs on Fly Ashes

    PubMed Central

    Potter, Phillip M.; Dellinger, Barry; Lomnicki, Slawomir M.

    2015-01-01

    Chlorinated aromatics undergo surface-mediated reactions with metal oxides to form Environmentally Persistent Free Radicals (EPFRs) which can further react to produce polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Previous work using laboratory-made fly ash surrogates composed of transition metal oxides deposited on silica powder has confirmed their ability to mimic fly ash in the production of PCDD/Fs. However, little is known about the propensity of aluminas and aluminosilicates, other components of fly ash, to form PCDD/Fs. A fly ash sample containing both alumina and mullite, an aluminosilicate, was tested for PCDD/F formation ability and compared to PCDD/F yields from the thermal degradation of 2-monochlorophenol (2-MCP) precursor over γ-alumina, α-alumina, and mullite. A packed-bed flow reactor was used to investigate the thermal degradation of 2-MCP over the various catalysts at 200–600 °C. Fly ash gave similar PCDD/F yields to surrogates made with similar transition metal content. γ-alumina, which is thermodynamically unfavorable, was very catalytically active and gave low PCDD/F yields despite a high destruction of 2-MCP. Mullite and α-alumina, the thermodynamically favorable form of alumina, yielded higher concentrations of dioxins and products with a higher degree of chlorine substitution than γ-alumina. The data suggest that certain aluminas and aluminosilicates, commonly found in fly ash, are active catalytic surfaces in the formation of PCDD/Fs in the post-flame cool zones of combustion systems and should be considered as additional catalytic surfaces active in the process. PMID:26615490

  19. COSTS FOR ADVANCED COAL COMBUSTION TECHNOLOGIES

    EPA Science Inventory

    The report gives results of an evaluation of the development status of advanced coal combustion technologies and discusses the preparation of performance and economic models for their application to electric utility plants. he technologies addressed were atmospheric fluidized bed...

  20. Fluidized Bed Boiler Assessment for Navy Applications

    DTIC Science & Technology

    1986-11-01

    inertia and latent heat stored in the bed material allow newly added fuel to ignite quickly and evenly; even wet or low-quality fuels can be burned...about 97% inert bed material (e.g., sand) and 3% fuel. The upper bed is composed of finely ground sulfur sorbent and is where desulfurization of...can be burned without the need of the expensive back-end desulfurization equipment. In fact, most FBC boilers can practically burn all combustible

  1. Combustion engineering issues for solid fuel systems

    SciTech Connect

    Bruce Miller; David Tillman

    2008-05-15

    The book combines modeling, policy/regulation and fuel properties with cutting edge breakthroughs in solid fuel combustion for electricity generation and industrial applications. This book provides real-life experiences and tips for addressing the various technical, operational and regulatory issues that are associated with the use of fuels. Contents are: Introduction; Coal Characteristics; Characteristics of Alternative Fuels; Characteristics and Behavior of Inorganic Constituents; Fuel Blending for Combustion Management; Fuel Preparation; Conventional Firing Systems; Fluidized-Bed Firing Systems; Post-Combustion Emissions Control; Some Computer Applications for Combustion Engineering with Solid Fuels; Gasification; Policy Considerations for Combustion Engineering.

  2. Fly ash zeolite catalyst support for Fischer-Tropsch synthesis

    NASA Astrophysics Data System (ADS)

    Campen, Adam

    This dissertation research aimed at evaluating a fly ash zeolite (FAZ) catalyst support for use in heterogeneous catalytic processes. Gas phase Fischer-Tropsch Synthesis (FTS) over a fixed-bed of the prepared catalyst/FAZ support was identified as an appropriate process for evaluation, by comparison with commercial catalyst supports (silica, alumina, and 13X). Fly ash, obtained from the Wabash River Generating Station, was first characterized using XRD, SEM/EDS, particle size, and nitrogen sorption techniques. Then, a parametric study of a two-step alkali fusion/hydrothermal treatment process for converting fly ash to zeolite frameworks was performed by varying the alkali fusion agent, agent:flyash ratio, fusion temperature, fused ash/water solution, aging time, and crystallization time. The optimal conditions for each were determined to be NaOH, 1.4 g NaOH: 1 g fly ash, 550 °C, 200 g/L, 12 hours, and 48 hours. This robust process was applied to the fly ash to obtain a faujasitic zeolite structure with increased crystallinity (40 %) and surface area (434 m2/g). Following the modification of fly ash to FAZ, ion exchange of H+ for Na+ and cobalt incipient wetness impregnation were used to prepare a FTS catalyst. FTS was performed on the catalysts at 250--300 °C, 300 psi, and with a syngas ratio H2:CO = 2. The HFAZ catalyst support loaded with 11 wt% cobalt resulted in a 75 % carbon selectivity for C5 -- C18 hydrocarbons, while methane and carbon dioxide were limited to 13 and 1 %, respectively. Catalyst characterization was performed by XRD, N2 sorption, TPR, and oxygen pulse titration to provide insight to the behavior of each catalyst. Overall, the HFAZ compared well with silica and 13X supports, and far exceeded the performance of the alumina support under the tested conditions. The successful completion of this research could add value to an underutilized waste product of coal combustion, in the form of catalyst supports in heterogeneous catalytic processes.

  3. Eco-friendly fly ash utilization: potential for land application

    SciTech Connect

    Malik, A.; Thapliyal, A.

    2009-07-01

    The increase in demand for power in domestic, agricultural, and industrial sectors has increased the pressure on coal combustion and aggravated the problem of fly ash generation/disposal. Consequently the research targeting effective utilization of fly ash has also gained momentum. Fly ash has proved to be an economical substitute for expensive adsorbents as well as a suitable raw material for brick manufacturing, zeolite synthesis, etc. Fly ash is a reservoir of essential minerals but is deficient in nitrogen and phosphorus. By amending fly ash with soil and/or various organic materials (sewage sludge, bioprocess materials) as well as microbial inoculants like mycorrhizae, enhanced plant growth can be realized. Based on the sound results of large scale studies, fly ash utilization has grown into prominent discipline supported by various internationally renowned organizations. This paper reviews attempts directed toward various utilization of fly ash, with an emphasis on land application of organic/microbial inoculants amended fly ash.

  4. DURABILITY EVALUATION AND PRODUCTION OF MANUFACTURED AGGREGATES FROM COAL COMBUSTION BY-PRODUCTS

    SciTech Connect

    M. M. Wu

    2005-02-01

    Under the cooperative agreement with DOE, the Research and Development Department of CONSOL Energy (CONSOL R&D), teamed with Universal Aggregates, LLC, to conduct a systematic study of the durability of aggregates manufactured using a variety of flue gas desulfurization (FGD), fluidized-bed combustion (FBC) and fly ash specimens with different chemical and physical properties and under different freeze/thaw, wet/dry and long-term natural weathering conditions. The objectives of the study are to establish the relationships among the durability and characteristics of FGD material, FBC ash and fly ash, and to identify the causes of durability problems, and, ultimately, to increase the utilization of FGD material, FBC ash and fly ash as a construction material. Manufactured aggregates made from FGD material, FBC ash and fly ash, and products made from those manufactured aggregates were used in the study. The project is divided into the following activities: sample collection and characterization; characterization and preparation of manufactured aggregates; determination of durability characteristics of manufactured aggregates; preparation and determination of durability characteristics of manufactured aggregate products; and data evaluation and reporting.

  5. Heat exchanger support apparatus in a fluidized bed

    DOEpatents

    Lawton, Carl W.

    1982-01-01

    A heat exchanger is mounted in the upper portion of a fluidized combusting bed for the control of the temperature of the bed. A support, made up of tubes, is extended from the perforated plate of the fluidized bed up to the heat exchanger. The tubular support framework for the heat exchanger has liquid circulated therethrough to prevent deterioration of the support.

  6. Dual fluidized bed design for the fast pyrolysis of biomass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A mechanism for the transport of solids between fluidised beds in dual fluidised bed systems for the fast pyrolysis of biomass process was selected. This mechanism makes use of an overflow standpipe to transport solids from the fluidised bed used for the combustion reactions to a second fluidised be...

  7. Development and Oviposition Preference of House Flies and Stable Flies (Diptera: Muscidae) in Six Substrates From Florida Equine Facilities.

    PubMed

    Machtinger, E T; Geden, C J; Hogsette, J A; Leppla, N C

    2014-11-01

    House flies, Musca domestica L., and stable flies, Stomoxys calcitrans (L.), (Diptera: Muscidae), common pests on equine facilities, were studied in the laboratory to determine the success and duration of larval development and oviposition preferences on six substrates commonly found on equine facilities. Substrates tested were hay soiled with urine and manure, fresh horse manure, pine shaving bedding soiled with urine and manure (<12 h old), pine shaving bedding soiled with urine and manure (aged >72 h in a manure pile), builders sand bedding soiled with urine and manure aged 3 d, and soil from an overgrazed pasture mixed with urine and manure of variable age. House fly larvae failed to develop into adults in hay, soil, and sand substrates. Stable flies preferred to oviposit on substrates with plant material and not on fresh manure. However, when eggs were added to the substrates, pupariation was maximal in fresh manure and the fresh pine shaving substrate. Stable flies developed in all six equine substrates, but development was less successful on the substrates with soil. In choice tests, fresh manure and the fresh pine shaving substrates were the most attractive for house fly oviposition. These substrates also yielded the greatest number of house fly puparia from artificially added eggs. An understanding of oviposition preferences and differential larval development of house flies and stable flies on these substrates may help develop options for reducing pest populations by effectively managing equine waste and selecting appropriate bedding materials.

  8. Combustion noise

    NASA Technical Reports Server (NTRS)

    Strahle, W. C.

    1977-01-01

    A review of the subject of combustion generated noise is presented. Combustion noise is an important noise source in industrial furnaces and process heaters, turbopropulsion and gas turbine systems, flaring operations, Diesel engines, and rocket engines. The state-of-the-art in combustion noise importance, understanding, prediction and scaling is presented for these systems. The fundamentals and available theories of combustion noise are given. Controversies in the field are discussed and recommendations for future research are made.

  9. Determination of the Cd-bearing phases in municipal solid waste and biomass single fly ash particles using SR-microXRF spectroscopy.

    PubMed

    Camerani, Maria Caterina; Somogyi, Andrea; Vekemans, Bart; Ansell, Stuart; Simionovici, Alexandre S; Steenari, Britt-Marie; Panas, Itai

    2007-09-01

    By using an excitation energy of 27.0 keV, synchrotron radiation-induced micro-X-ray fluorescence (SR-microXRF) is employed to extract information regarding the composition and distribution of Cd-bearing phases in municipal solid waste (MSW) and biomass fly ashes. Significance of observation is based on statistics of totally more than 100 individual MSW and biomass fly ash particles from a fluidized bed combustion (FBC) plant. Cd concentrations in the parts-per-million range are determined. In general, although previous leaching studies have indicated Cd to be predominant in the smaller-size ash particles, in the present study Cd is more evenly distributed throughout all the particle sizes. For MSW fly ashes, results indicate the presence of Cd mainly as CdBr2 hot-spots, whereas for biomass fly ashes, which exhibit lower CdX2 concentration, a thin Cd layer on/in the particles is reported. For both ashes, Ca-containing matrixes are found to be the main Cd-bearing phases. Support for this observation is found from independent first-principles periodic density functional theory calculations. The observations are condensed into a schematic mechanism for Cd adsorption on the fly ash particles.

  10. Fluidized bed charcoal particle production system

    SciTech Connect

    Sowards, N.K.

    1985-04-09

    A fluidized bed charcoal particle production system, including apparatus and method, wherein pieces of combustible waste, such as sawdust, fragments of wood, etc., are continuously disposed within a fluidized bed of a pyrolytic vessel. Preferably, the fluidized bed is caused to reach operating temperatures by use of an external pre-heater. The fluidized bed is situated above an air delivery system at the bottom of the vessel, which supports pyrolysis within the fluidized bed. Charcoal particles are thus formed within the bed from the combustible waste and are lifted from the bed and placed in suspension above the bed by forced air passing upwardly through the bed. The suspended charcoal particles and the gaseous medium in which the particles are suspended are displaced from the vessel into a cyclone mechanism where the charcoal particles are separated. The separated charcoal particles are quenched with water to terminate all further charcoal oxidation. The remaining off-gas is burned and, preferably, the heat therefrom used to generate steam, kiln dry lumber, etc. Preferably, the bed material is continuously recirculated and purified by removing tramp material.

  11. Method for in situ combustion

    DOEpatents

    Pasini, III, Joseph; Shuck, Lowell Z.; Overbey, Jr., William K.

    1977-01-01

    This invention relates to an improved in situ combustion method for the recovery of hydrocarbons from subterranean earth formations containing carbonaceous material. The method is practiced by penetrating the subterranean earth formation with a borehole projecting into the coal bed along a horizontal plane and extending along a plane disposed perpendicular to the plane of maximum permeability. The subterranean earth formation is also penetrated with a plurality of spaced-apart vertical boreholes disposed along a plane spaced from and generally parallel to that of the horizontal borehole. Fractures are then induced at each of the vertical boreholes which project from the vertical boreholes along the plane of maximum permeability and intersect the horizontal borehole. The combustion is initiated at the horizontal borehole and the products of combustion and fluids displaced from the earth formation by the combustion are removed from the subterranean earth formation via the vertical boreholes. Each of the vertical boreholes are, in turn, provided with suitable flow controls for regulating the flow of fluid from the combustion zone and the earth formation so as to control the configuration and rate of propagation of the combustion zone. The fractures provide a positive communication with the combustion zone so as to facilitate the removal of the products resulting from the combustion of the carbonaceous material.

  12. Combined fluidized bed retort and combustor

    DOEpatents

    Shang, Jer-Yu; Notestein, John E.; Mei, Joseph S.; Zeng, Li-Wen

    1984-01-01

    The present invention is directed to a combined fluidized bed retorting and combustion system particularly useful for extracting energy values from oil shale. The oil-shale retort and combustor are disposed side-by-side and in registry with one another through passageways in a partition therebetween. The passageways in the partition are submerged below the top of the respective fluid beds to preclude admixing or the product gases from the two chambers. The solid oil shale or bed material is transported through the chambers by inclining or slanting the fluidizing medium distributor so that the solid bed material, when fluidized, moves in the direction of the downward slope of the distributor.

  13. Computational Combustion

    SciTech Connect

    Westbrook, C K; Mizobuchi, Y; Poinsot, T J; Smith, P J; Warnatz, J

    2004-08-26

    Progress in the field of computational combustion over the past 50 years is reviewed. Particular attention is given to those classes of models that are common to most system modeling efforts, including fluid dynamics, chemical kinetics, liquid sprays, and turbulent flame models. The developments in combustion modeling are placed into the time-dependent context of the accompanying exponential growth in computer capabilities and Moore's Law. Superimposed on this steady growth, the occasional sudden advances in modeling capabilities are identified and their impacts are discussed. Integration of submodels into system models for spark ignition, diesel and homogeneous charge, compression ignition engines, surface and catalytic combustion, pulse combustion, and detonations are described. Finally, the current state of combustion modeling is illustrated by descriptions of a very large jet lifted 3D turbulent hydrogen flame with direct numerical simulation and 3D large eddy simulations of practical gas burner combustion devices.

  14. Simulating Combustion

    NASA Astrophysics Data System (ADS)

    Merker, G.; Schwarz, C.; Stiesch, G.; Otto, F.

    The content spans from simple thermodynamics of the combustion engine to complex models for the description of the air/fuel mixture, ignition, combustion and pollutant formation considering the engine periphery of petrol and diesel engines. Thus the emphasis of the book is on the simulation models and how they are applicable for the development of modern combustion engines. Computers can be used as the engineers testbench following the rules and recommendations described here.

  15. Fluidized bed combustor and tube construction therefor

    DOEpatents

    De Feo, Angelo; Hosek, William

    1981-01-01

    A fluidized bed combustor comprises a reactor or a housing which has a windbox distributor plate adjacent the lower end thereof which contains a multiplicity of hole and air discharge nozzles for discharging air and coal into a fluidized bed which is maintained above the distributor plate and below a take-off connection or flue to a cyclone separator in which some of the products of combustion are treated to remove the dust which is returned into the fluidized bed. A windbox is spaced below the fluidized bed and it has a plurality of tubes passing therethrough with the passage of combustion air and fluidizing air which passes through an air space so that fluidizing air is discharged into the reaction chamber fluidized bed at the bottom thereof to maintain the bed in a fluidized condition. A fluid, such as air, is passed through the tubes which extend through the windbox and provide a preheating of the combustion air and into an annular space between telescoped inner and outer tubes which comprise heat exchanger tubes or cooling tubes which extend upwardly through the distributor plate into the fluidized bed. The heat exchanger tubes are advantageously arranged so that they may be exposed in groups within the reactor in a cluster which is arranged within holding rings.

  16. Tube construction for fluidized bed combustor

    DOEpatents

    De Feo, Angelo; Hosek, William

    1984-01-01

    A fluidized bed combustor comprises a reactor or a housing which has a windbox distributor plate adjacent the lower end thereof which contains a multiplicity of hole and air discharge nozzles for discharging air and coal into a fluidized bed which is maintained above the distributor plate and below a take-off connection or flue to a cyclone separator in which some of the products of combustion are treated to remove the dust which is returned into the fluidized bed. A windbox is spaced below the fluidized bed and it has a plurality of tubes passing therethrough with the passage of combustion air and fluidizing air which passes through an air space so that fluidizing air is discharged into the reaction chamber fluidized bed at the bottom thereof to maintain the bed in a fluidized condition. A fluid, such as air, is passed through the tubes which extend through the windbox and provide a preheating of the combustion air and into an annular space between telescoped inner and outer tubes which comprise heat exchanger tubes or cooling tubes which extend upwardly through the distributor plate into the fluidized bed. The heat exchanger tubes are advantageously arranged so that they may be exposed in groups within the reactor in a cluster which is arranged within holding rings.

  17. Symposium /International/ on Combustion, 18th, University of Waterloo, Waterloo, Ontario, Canada, August 17-22, 1980, Proceedings

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Problems related to combustion generated pollution are explored, taking into account the mechanism of NO formation from nitrogen compounds in hydrogen flames studied by laser fluorescence, the structure and similarity of nitric oxide production in turbulent diffusion flames, the effect of steam addition on NO formation, and the formation of NO2 by laminar flames. Other topics considered are concerned with propellant combustion, fluidized bed combustion, the combustion of droplets and sprays, premixed flame studies, fire studies, and flame stabilization. Attention is also given to coal flammability, chemical kinetics, turbulent combustion, soot, coal combustion, the modeling of combustion processes, combustion diagnostics, detonations and explosions, ignition, internal combustion engines, combustion studies, and furnaces.

  18. Development of a new method for improving load turndown in fluidized bed combustors: Final report

    SciTech Connect

    Brown, R.C.

    1988-12-01

    The objective of this research was to investigate a new concept in fluidized bed design that improves load turndown capability. This improvement is accomplished by independently controlling heat transfer and combustion in the combustor. The design consists of two fluidized beds, one central and one annular. The central bed serves as the combustion bed. The annular bed is fluidized separately from the combustion bed and its level of fluidization determine the overall heat transfer rate from the combustion bed to the surrounding water jacket. Early theoretical considerations suggested a load turndown exceeding ten was possible for this design. This research consisted of three major phases: development of a computational model to predict heat transfer in the two-bed combustor, heat transfer measurements in hot-and-cold flow models of the combustor, and combustion tests in an optimally designed combustor. The computation model was useful in selecting the design of the combustor. Annular bed width and particle sizes were chosen with the aid of the model. The heat transfer tests were performed to determine if the existing correlations for fluidized bed heat transfer coefficients were sufficiently accurate for high aspect ratio fluidized beds (such as the annular bed in the combustor). Combustion tests were performed in an optimally designed combustor. Three fuel forms were used: double screened, crushed coal, coal-water-limestone mixtures (CWLM), and coal-limestone briquettes. 18 refs., 30 figs., 8 tabs.

  19. Solid fuel feed system for a fluidized bed

    DOEpatents

    Jones, Brian C.

    1982-01-01

    A fluidized bed for the combustion of coal, with limestone, is replenished with crushed coal from a system discharging the coal laterally from a station below the surface level of the bed. A compartment, or feed box, is mounted at one side of the bed and its interior separated from the bed by a weir plate beneath which the coal flows laterally into the bed while bed material is received into the compartment above the plate to maintain a predetermined minimum level of material in the compartment.

  20. Fluidized bed heat exchanger utilizing angularly extending heat exchange tubes

    DOEpatents

    Talmud, Fred M.; Garcia-Mallol, Juan-Antonio

    1980-01-01

    A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided and includes a steam drum disposed adjacent the fluidized bed and a series of tubes connected at one end to the steam drum. A portion of the tubes are connected to a water drum and in the path of the air and the gaseous products of combustion exiting from the bed. Another portion of the tubes pass through the bed and extend at an angle to the upper surface of the bed.

  1. Chemicl-looping combustion of coal with metal oxide oxygen carriers

    SciTech Connect

    Siriwardane, R.; Tian, H.; Richards, G.; Simonyi, T.; Poston, J.

    2009-01-01

    The combustion and reoxidation properties of direct coal chemical-looping combustion (CLC) over CuO, Fe2O3, Co3O4, NiO, and Mn2O3 were investigated using thermogravimetric analysis (TGA) and bench-scale fixed-bed flow reactor studies. When coal is heated in either nitrogen or carbon dioxide (CO2), 50% of weight loss was observed because of partial pyrolysis, consistent with the proximate analysis. Among various metal oxides evaluated, CuO showed the best reaction properties: CuO can initiate the reduction reaction as low as 500 °C and complete the full combustion at 700 °C. In addition, the reduced copper can be fully reoxidized by air at 700 °C. The combustion products formed during the CLC reaction of the coal/metal oxide mixture are CO2 and water, while no carbon monoxide was observed. Multicycle TGA tests and bench-scale fixed-bed flow reactor tests strongly supported the feasibility of CLC of coal by using CuO as an oxygen carrier. Scanning electron microscopy (SEM) images of solid reaction products indicated some changes in the surface morphology of a CuO-coal sample after reduction/oxidation reactions at 800 °C. However, significant surface sintering was not observed. The interactions of fly ash with metal oxides were investigated by X-ray diffraction and thermodynamic analysis. Overall, the results indicated that it is feasible to develop CLC with coal by metal oxides as oxygen carriers.

  2. Chemical-looping combustion of coal with metal oxide oxygen carriers

    SciTech Connect

    Ranjani Siriwardane; Hanjing Tian; George Richards; Thomas Simonyi; James Poston

    2009-08-15

    The combustion and reoxidation properties of direct coal chemical-looping combustion (CLC) over CuO, Fe{sub 2}O{sub 3}, CO{sub 3}O{sub 4}, NiO, and Mn{sub 2}O{sub 3} were investigated using thermogravimetric analysis (TGA) and bench-scale fixed-bed flow reactor studies. When coal is heated in either nitrogen or carbon dioxide (CO{sub 2}), 50% of weight loss was observed because of partial pyrolysis, consistent with the proximate analysis. Among various metal oxides evaluated, CuO showed the best reaction properties: CuO can initiate the reduction reaction as low as 500{sup o}C and complete the full combustion at 700{sup o}C. In addition, the reduced copper can be fully reoxidized by air at 700{sup o}C. The combustion products formed during the CLC reaction of the coal/metal oxide mixture are CO{sub 2} and water, while no carbon monoxide was observed. Multicycle TGA tests and bench-scale fixed-bed flow reactor tests strongly supported the feasibility of CLC of coal by using CuO as an oxygen carrier. Scanning electron microscopy (SEM) images of solid reaction products indicated some changes in the surface morphology of a CuO-coal sample after reduction/oxidation reactions at 800 {sup o}C. However, significant surface sintering was not observed. The interactions of fly ash with metal oxides were investigated by X-ray diffraction and thermodynamic analysis. Overall, the results indicated that it is feasible to develop CLC with coal by metal oxides as oxygen carriers. 22 refs., 12 figs., 2 tabs.

  3. Method for increasing the calorific value of gas produced by the in situ combustion of coal

    DOEpatents

    Shuck, Lowell Z.

    1978-01-01

    The present invention relates to the production of relatively high Btu gas by the in situ combustion of subterranean coal. The coal bed is penetrated with a horizontally-extending borehole and combustion is initiated in the coal bed contiguous to the borehole. The absolute pressure within the resulting combustion zone is then regulated at a desired value near the pore pressure within the coal bed so that selected quantities of water naturally present in the coal will flow into the combustion zone to effect a hydrogen and carbon monoxide-producing steam-carbon reaction with the hot carbon in the combustion zone for increasing the calorific value of the product gas.

  4. Pulsed atmospheric fluidized bed combustor apparatus

    DOEpatents

    Mansour, Momtaz N.

    1993-10-26

    A pulsed atmospheric fluidized bed reactor system is disclosed and claimed along with a process for utilization of same for the combustion of, e.g. high sulfur content coal. The system affords a economical, ecologically acceptable alternative to oil and gas fired combustors. The apparatus may also be employed for endothermic reaction, combustion of waste products, e.g., organic and medical waste, drying materials, heating air, calcining and the like.

  5. Fluid-bed air-supply system

    DOEpatents

    Atabay, Keramettin

    1979-01-01

    The air-supply system for a fluidized-bed furnace includes two air conduits for the same combustion zone. The conduits feed separate sets of holes in a distributor plate through which fluidizing air flows to reach the bed. During normal operation, only one conduit and set of holes is used, but the second conduit and set of holes is employed during start-up.

  6. Using fly ash to mitigate explosions

    SciTech Connect

    Taulbee, D.

    2008-07-01

    In 2005 the University of Kentucky's Center for Applied Energy Research was given funding to evaluate the use of coal combustion by-products (CCBs) to reduce the explosive potential of ammonium nitrate (AN) fertilizers. Fly ash C (FAC), fly ash F (FAF) and flue gas desulfurization by-product (FGD) were evaluated. It was found that applying a CCB coating to the AN particles at concentrations of 5 wt% or greater prevented the AN explosion from propagating. The article reports on results so far and outlines further work to be done. 6 figs.

  7. [Distribution of fluoride in the combustion products of coal].

    PubMed

    Liu, Jianzhong; Qi, Qingjie; Zhou, Junhu; Cao, Xinyu; Cen, Kefa

    2003-07-01

    The static distribution characteristic of fluoride in the combustion products of coal was studied by ashing procedure of coal, and the dynamic distribution characteristics of fluorine in the combustion products of coal in pulverized-coal-fired boiler and layer-burning boiler were investigated. Experimental results identified that fluorine in coal belong to volatile elements, fluorine in fly ash and bottom ash were non-rich. About 94.5% of the fluorine in coal emitted as gaseous-fluorine during coal combustion in pulverized-coal-fired boiler, and about 80% of the fluorine in coal emitted as gaseous-fluorine during coal combustion in layer-burning boiler. 55%-60% of the fluorine in fly ash of pulverized-coal-fired boiler were distributed in fly ash particles with a diameter of 74 microns-104 microns.

  8. TOXIC SUBSTANCES FROM COAL COMBUSTION-A COMPREHENSIVE ASSESSMENT

    SciTech Connect

    C.L. Senior; F. Huggins; G.P. Huffman; N. Shah; N. Yap; J.O.L. Wendt; W. Seames; M.R. Ames; A.F. Sarofim; S. Swenson; J.S. Lighty; A. Kolker; R. Finkelman; C.A. Palmer; S.J. Mroczkowski; J.J. Helble; R. Mamani-Paco; R. Sterling; G. Dunham; S. Miller

    2001-06-30

    focused on the behavior of trace metals in the combustion zone by studying vaporization from single coal particles. The coals were burned at 1700 K under a series of fuel-rich and oxygen-rich conditions. The data collected in this study will be applied to a model that accounts for the full equilibrium between carbon monoxide and carbon dioxide. The model also considers many other reactions taking place in the combustion zone, and involves the diffusion of gases into the particle and combustion products away from the particle. A comprehensive study has been conducted at UA to investigate the post-combustion partitioning of trace elements during large-scale combustion of pulverized coal combustion. For many coals, there are three distinct particle regions developed by three separate mechanisms: (1) a submicron fume, (2) a micron-sized fragmentation region, and (3) a bulk (>3 {micro}m) fly ash region. The controlling partitioning mechanisms for trace elements may be different in each of the three particle regions. A substantial majority of semi-volatile trace elements (e.g., As, Se, Sb, Cd, Zn, Pb) volatilize during combustion. The most common partitioning mechanism for semi-volatile elements is reaction with active fly ash surface sites. Experiments conducted under this program at UC focused on measuring mercury oxidation under cooling rates representative of the convective section of a coal-fired boiler to determine the extent of homogeneous mercury oxidation under these conditions. In fixed bed studies at EERC, five different test series were planned to evaluate the effects of temperature, mercury concentration, mercury species, stoichiometric ratio of combustion air, and ash source. Ash samples generated at UA and collected from full-scale power plants were evaluated. Extensive work was carried out at UK during this program to develop new methods for identification of mercury species in fly ash and sorbents. We demonstrated the usefulness of XAFS spectroscopy for the

  9. UTILIZATION OF LOW NOx COAL COMBUSTION BY-PRODUCTS

    SciTech Connect

    J.Y. Hwang; X. Huang; M.G. McKimpson; R.E. Tieder; A.M. Hein; J.M. Gillis; D.C. Popko; K.L. Paxton; Z. Li; X. Liu; X. Song; R.I. Kramer

    1998-12-01

    Low NO{sub x} combustion practices are critical for reducing NO{sub x} emissions from power plants. These low NO{sub x} combustion practices, however, generate high residual carbon contents in the fly ash produced. These high carbon contents threaten utilization of this combustion by-product. This research has successfully developed a separation technology to render fly ash into useful, quality-controlled materials. This technology offers great flexibility and has been shown to be applicable to all of the fly ashes tested (more than 10). The separated materials can be utilized in traditional fly ash applications, such as cement and concrete, as well as in nontraditional applications such as plastic fillers, metal matrix composites, refractories, and carbon adsorbents. Technologies to use beneficiated fly ash in these applications are being successfully developed. In the future, we will continue to refine the separation and utilization technologies to expand the utilization of fly ash. The disposal of more than 31 million tons of fly ash per year is an important environmental issue. With continued development, it will be possible to increase economic, energy and environmental benefits by re-directing more of this fly ash into useful materials.

  10. Fluidized-bed boilers achieve commercial status worldwide

    SciTech Connect

    Schwieger, B.

    1985-02-01

    The author reviews the current status of commercial fluidized-bed boilers worldwide. Particular attention is given to circulating fluidised-bed systems. A number of detailed tables are presented providing details of manufacturers of afb boilers, and information on 88 installed boilers, their fuels, combustion systems and operational data. Less detailed information is given of a further 140 installations.

  11. Passive treatment of acid mine drainage using coal combustion by-products and spent mushroom substrate: Results of column study

    SciTech Connect

    Crisp, T.E.; Nairn, R.W.; Strevett, K.A.; Everett, J.

    1998-12-31

    A column study was conducted to evaluate the feasibility of using of coal combustion by-products (CCB) as alkaline materials in a field scale downflow constructed wetlands for acid mine drainage treatment. Five columns (15.24 cm in diameter and 91.44 cm high) were constructed and filled with a combination of spent mushroom substrate (SMS) and one of three alkaline materials (limestone, hydrated fly ash, or fluidized bed ash). The five mixtures utilized were 10% fluidized bed ash/40% limestone (FBA/LS), 10% fluidized bed ash (FBA), 50% limestone (LS), 50% hydrated fly ash (HFA),m and 50% sieved (>1.5 cm) hydrated fly ash (S. HFA) with the remainder as SMS on a w/w basis. Column received synthetic acid mine drainage containing: 400 mg/L iron, 59 mg/L aluminum, 11 mg/L manganese, 50% mg/L magnesium, 40 mg/L calcium, and 1200 mg/L sulfate for 5 months. Anoxic conditions in the influent reservoirs were maintained by a positive nitrogen pressure head. Flow rates of 2.0 mL/minute to each column were maintained by a multichannel peristaltic pump. For all columns, effluent acidity concentrations were less than influent acidity concentration (877{sup {minus}}30, n = 75f). Mean effluent acidity concentrations were 241 mg/L (FBA/LS), 186 mg/L (FBA), 419 mg/L (LS), {minus}28.5 mg/L (HFA), and 351 mg/L (S. HFA), respectively. While all column produced measurable alkalinity, only the HFA column produced a net alkaline discharge. The results of these column studies are applicable to the design and sizing of innovative field scale systems using alkaline-rich CCB`s.

  12. Lightweight combustion residues-based structural materials for use in mines. Quarterly report, 1 March 1995--31 May 1995

    SciTech Connect

    Chugh, Y.P.; Zhang, Yuzhuo; Ghosh, A.K.; Palmer, S.R.; Peng, Suping; Xiao, Y

    1995-12-31

    The overall goal of this PrOject is to develop, design, and test artificial supports (post and crib members), for use in mines, which will be manufactured from coal combustion by-products (CCB) based lightweight structural materials. During the last quarter (Dec. 1, 1994--Feb. 28, 1995), it was reported that low LOI ({approx}5%) F-fly ash-based lightweight materials with density ranging from 70-1 110 pcf and compressive strength ranging from about 1,500 psi to 5,000 psi had been developed. During this quarter, 1) similar materials were developed using higher LOI ({approx}1O%) F-fly ash, 2) performance of materials using nylon fibers rather than polypropylene fibers was examined, 3) effect of addition of small amounts of FBC spent bed material on strength-deformation properties was evaluated, 4) flexural strength tests were performed on 2 in. X 2 in. X 12 in. cast beams, 5) compressive strength tests were performed on cast hollow cylinders (6 in. outer diameter, 2.762 in. inner diameter and 12 in. long) and 6) limited number of tests were conducted to determine the effect of mixing speed on strength of developed materials. The results of these studies indicate that 1) suitable lightweight materials using 60--65% higher LOI F-fly ash can be developed for fabrication of artificial supports, 2) nylon fibers perform significantly better than Polypropylene fibers, 3) loss of strength and deformability due to the use of higher LOI fly ash can be offset to some extent by adding 5--10% FBC spent bed material, 4) relationship between flexural strength and compressive strength, similar to that in concrete exists, 5) strength-deformation properties of hollow cylinders are similar to 3 in. X 6 in. solid cylinders, and 6) strength and deformation modulus increase with mixing speed. Two mixes for final development of lightweight materials have been identified and final test` will begin June 1, 1995.

  13. Method for in situ gasification of a subterranean coal bed

    DOEpatents

    Shuck, Lowell Z.

    1977-05-31

    The method of the present invention relates to providing controlled directional bores in subterranean earth formations, especially coal beds for facilitating in situ gasification operations. Boreholes penetrating the coal beds are interconnected by laser-drilled bores disposed in various arrays at selected angles to the major permeability direction in the coal bed. These laser-drilled bores are enlarged by fracturing prior to the gasification of the coal bed to facilitate the establishing of combustion zones of selected configurations in the coal bed for maximizing the efficiency of the gasification operation.

  14. BIOLOGICAL EFFECTS OF OIL FLY ASH AND RELEVANCE TO AMBIENT AIR PARTICULATE MATTER

    EPA Science Inventory

    Epidemiologic studies have demonstrated increased human morbidity and mortality with elevations in the concentration of ambient air particulate matter (PM). Fugitive fly ash from the combustion of oil and residual fuel oil significantly contributes to the ambient air particle bur...

  15. Co-firing of oil sludge with coal-water slurry in an industrial internal circulating fluidized bed boiler.

    PubMed

    Liu, Jianguo; Jiang, Xiumin; Zhou, Lingsheng; Wang, Hui; Han, Xiangxin

    2009-08-15

    Incineration has been proven to be an alternative for disposal of sludge with its unique characteristics to minimize the volume and recover energy. In this paper, a new fluidized bed (FB) incineration system for treating oil sludge is presented. Co-firing of oil sludge with coal-water slurry (CWS) was investigated in the new incineration system to study combustion characteristics, gaseous pollutant emissions and ash management. The study results show the co-firing of oil sludge with CWS in FB has good operating characteristic. CWS as an auxiliary fuel can flexibly control the dense bed temperatures by adjusting its feeding rate. All emissions met the local environmental requirements. The CO emission was less than 1 ppm or essentially zero; the emissions of SO(2) and NO(x) were 120-220 and 120-160 mg/Nm(3), respectively. The heavy metal analyses of the bottom ash and the fly ash by ICP/AES show that the combustion ashes could be recycled as soil for farming.

  16. Fluidized-Bed Waste-Heat Recovery System development. Semiannual report, 1 August 1982-31 January 1983

    SciTech Connect

    Cole, W.E.; DeSaro, R.; Joshi, C.

    1983-02-01

    The Fluidized-Bed Waste-Heat Recovery (FBWHR) System is designed to preheat this combustion air using the heat available in dirty flue gas streams. In this system, a recirculating medium is heated by the flue gas in a fluidized bed. The hot medium is then removed from the bed and placed in a second fluidized bed where it is fluidized by the combustion air. Through this process, the combustion air is heated. The cooled medium is then returned to the first bed. Initial development of this concept is for the aluminum smelting industry.

  17. Fluidized-Bed Waste-Heat Recovery System development. Semiannual report, 1 August 1981-31 January 1982

    SciTech Connect

    Cole, W. E.; DeSaro, R.; Joshi, C.

    1982-02-01

    The Fluidized-Bed Waste-Heat Recovery (FBWHR) System is designed to preheat this combustion air using the heat available in dirty flue gas streams. In this system, a recirculating medium is heated by the flue gas in a fluidized bed. The hot medium is then removed from the bed and placed in a second fluidized bed where it is fluidized by the combustion air. Through this process, the combustion air is heated. The cooled medium is then returned to the first bed. Initial development of this concept is for the aluminum smelting industry.

  18. Lightweight combustion residues-based structural materials for use in mines. Technical report, September 1--November 30, 1994

    SciTech Connect

    Chugh, Y.P.; Zhang, Y.; Ghosh, A.K.; Palmer, S.R.

    1994-12-31

    The overall goal of the project is to develop a 70--80 pcf, 2,500--3,000 psi-compressive-strength cellular concrete-type product from PCC fly ash, PCC bottom ash, and/or FBC spent bed ash alone or in suitable combination thereof. The developed combustion residue-based lightweight structural material will be used to replace wooden posts and crib members in underground mines. This report outlines the work completed in the first quarter of the project. The density gradient centrifuge (DGC) has been used to separate a power plant fly ash sample into fractions of different density. Each of the fly ash fractions obtained by DGC, an aliquot of the unseparated fly ash and an aliquot of a magnetic component of the fly ash, were digested in strong acids following the procedures outlined in ASTM 3050. Preliminary experiments have also been carried out to study the effect of mix proportions and curing regimes on the strength and density on the developed material. The DGC separation test reveals that most of the fly ash sample (approx. 90%) has a density above 1.9 g/cm{sup 3}. Indeed, nearly half of the sample has a density greater than 2.4 g/cm{sup 3}. Since only a very small amount of this fly ash has a reasonably low specific gravity, it appears unlikely at this time that enough low density material would be isolated to significantly enhance lightweight concrete production using fractionated material. A series of mixes have been made using fly ash, sodium silicate, cement, sand and water. Preliminary tests show that both cement and sodium silicate can be used as the binders to develop residues-based lightweight concrete. To date, compressive strength as high as 1,290 psi have been achieved with a density of 133 pcf, with 50 g of cement, 50 g of fly ash and 300 g of sand. Most of the work during the first quarter was done to understand the characteristics of the component materials.

  19. Removal of heavy metals from wastewater using CFB-coal fly ash zeolitic materials.

    PubMed

    Koukouzas, Nikolaos; Vasilatos, Charalampos; Itskos, Grigorios; Mitsis, Ioannis; Moutsatsou, Angeliki

    2010-01-15

    Polish bituminous (PB) and South African (SA) coal fly ash (FA) samples, derived from pilot-scale circulated fluidized bed (CFB) combustion facilities, were utilized as raw materials for the synthesis of zeolitic products. The two FAs underwent a hydrothermal activation with 1M NaOH solution. Two different FA/NaOH solution/ratios (50, 100g/L) were applied for each sample and several zeolitic materials were formed. The experimental products were characterized by means of X-ray diffraction (XRD) and energy dispersive X-ray coupled-scanning electron microscope (EDX/SEM), while X-ray fluorescence (XRF) was applied for the determination of their chemical composition. The zeolitic products were also evaluated in terms of their cation exchange capacity (CEC), specific surface area (SSA), specific gravity (SG), particle size distribution (PSD), pH and the range of their micro- and macroporosity. Afterwards the hybrid materials were tested for their ability of adsorbing Cr, Pb, Ni, Cu, Cd and Zn from contaminated liquids. Main parameters for the precipitation of the heavy metals, as it was concluded from the experimental results, are the mineralogical composition of the initial fly ashes, as well as the type and the amount of the produced zeolite and specifically the mechanism by which the metals ions are hold on the substrate.

  20. Biofuels Combustion

    NASA Astrophysics Data System (ADS)

    Westbrook, Charles K.

    2013-04-01

    This review describes major features of current research in renewable fuels derived from plants and from fatty acids. Recent and ongoing fundamental studies of biofuel molecular structure, oxidation reactions, and biofuel chemical properties are reviewed, in addition to combustion applications of biofuels in the major types of engines in which biofuels are used. Biofuels and their combustion are compared with combustion features of conventional petroleum-based fuels. Two main classes of biofuels are described, those consisting of small, primarily alcohol, fuels (particularly ethanol, n-butanol, and iso-pentanol) that are used primarily to replace or supplement gasoline and those derived from fatty acids and used primarily to replace or supplement conventional diesel fuels. Research efforts on so-called second- and third-generation biofuels are discussed briefly.

  1. Biofuels combustion.

    PubMed

    Westbrook, Charles K

    2013-01-01

    This review describes major features of current research in renewable fuels derived from plants and from fatty acids. Recent and ongoing fundamental studies of biofuel molecular structure, oxidation reactions, and biofuel chemical properties are reviewed, in addition to combustion applications of biofuels in the major types of engines in which biofuels are used. Biofuels and their combustion are compared with combustion features of conventional petroleum-based fuels. Two main classes of biofuels are described, those consisting of small, primarily alcohol, fuels (particularly ethanol, n-butanol, and iso-pentanol) that are used primarily to replace or supplement gasoline and those derived from fatty acids and used primarily to replace or supplement conventional diesel fuels. Research efforts on so-called second- and third-generation biofuels are discussed briefly.

  2. Biofuels combustion*

    SciTech Connect

    Westbrook, Charles K.

    2013-01-04

    This review describes major features of current research in renewable fuels derived from plants and from fatty acids. Recent and ongoing fundamental studies of biofuel molecular structure, oxidation reactions, and biofuel chemical properties are reviewed, in addition to combustion applications of biofuels in the major types of engines in which biofuels are used. Biofuels and their combustion are compared with combustion features of conventional petroleum-based fuels. Two main classes of biofuels are described, those consisting of small, primarily alcohol, fuels (particularly ethanol, n-butanol, and iso-pentanol) that are used primarily to replace or supplement gasoline and those derived from fatty acids and used primarily to replace or supplement conventional diesel fuels. As a result, research efforts on so-called second- and third-generation biofuels are discussed briefly.

  3. Bubble Combustion

    NASA Technical Reports Server (NTRS)

    Corrigan, Jackie

    2004-01-01

    A method of energy production that is capable of low pollutant emissions is fundamental to one of the four pillars of NASA s Aeronautics Blueprint: Revolutionary Vehicles. Bubble combustion, a new engine technology currently being developed at Glenn Research Center promises to provide low emissions combustion in support of NASA s vision under the Emissions Element because it generates power, while minimizing the production of carbon dioxide (CO2) and nitrous oxides (NOx), both known to be Greenhouse gases. and allows the use of alternative fuels such as corn oil, low-grade fuels, and even used motor oil. Bubble combustion is analogous to the inverse of spray combustion: the difference between bubble and spray combustion is that spray combustion is spraying a liquid in to a gas to form droplets, whereas bubble combustion involves injecting a gas into a liquid to form gaseous bubbles. In bubble combustion, the process for the ignition of the bubbles takes place on a time scale of less than a nanosecond and begins with acoustic waves perturbing each bubble. This perturbation causes the local pressure to drop below the vapor pressure of the liquid thus producing cavitation in which the bubble diameter grows, and upon reversal of the oscillating pressure field, the bubble then collapses rapidly with the aid of the high surface tension forces acting on the wall of the bubble. The rapid and violent collapse causes the temperatures inside the bubbles to soar as a result of adiabatic heating. As the temperatures rise, the gaseous contents of the bubble ignite with the bubble itself serving as its own combustion chamber. After ignition, this is the time in the bubble s life cycle where power is generated, and CO2, and NOx among other species, are produced. However, the pollutants CO2 and NOx are absorbed into the surrounding liquid. The importance of bubble combustion is that it generates power using a simple and compact device. We conducted a parametric study using CAVCHEM

  4. Biofuels combustion*

    DOE PAGES

    Westbrook, Charles K.

    2013-01-04

    This review describes major features of current research in renewable fuels derived from plants and from fatty acids. Recent and ongoing fundamental studies of biofuel molecular structure, oxidation reactions, and biofuel chemical properties are reviewed, in addition to combustion applications of biofuels in the major types of engines in which biofuels are used. Biofuels and their combustion are compared with combustion features of conventional petroleum-based fuels. Two main classes of biofuels are described, those consisting of small, primarily alcohol, fuels (particularly ethanol, n-butanol, and iso-pentanol) that are used primarily to replace or supplement gasoline and those derived from fatty acidsmore » and used primarily to replace or supplement conventional diesel fuels. As a result, research efforts on so-called second- and third-generation biofuels are discussed briefly.« less

  5. A staged fluidized-bed comubstion and filter system

    SciTech Connect

    Mei, J.S.; Halow, J.S.

    1993-12-31

    A staged fluidized-bed combustion and filter system for substantially reducing the quantity of waste through the complete combustion into ash-type solids and gaseous products. The device has two fluidized- bed portions, the first primarily as a combustor/pyrolyzer bed, and the second as a combustor/filter bed. The two portions each have internal baffles to define stages so that material moving therein as fluidized beds travel in an extended route through those stages. Fluidization and movement is achieved by the introduction of gasses into each stage through a directional nozzle. Gases produced in the combustor/pyrolyzer bed are permitted to travel into corresponding stages of the combustor/filter bed through screen filters that permit gas flow but inhibit solids flow. Any catalyst used in the combustor/filter bed is recycled. The two beds share a common wall to minimize total volume of the system. A slightly modified embodiment can be used for hot gas desulfurization and sorbent regeneration. Either side-by-side rectangular beds or concentric beds can be used. The system is particularly suited to the processing of radioactive and chemically hazardous waste.

  6. Combustion Byproducts Recycling Consortium

    SciTech Connect

    Ziemkiewicz, Paul; Vandivort, Tamara; Pflughoeft-Hassett, Debra; Chugh, Y Paul; Hower, James

    2008-08-31

    Each year, over 100 million tons of solid byproducts are produced by coal-burning electric utilities in the United States. Annual production of flue gas desulfurization (FGD) byproducts continues to increase as the result of more stringent sulfur emission restrictions. In addition, stricter limits on NOx emissions mandated by the 1990 Clean Air Act have resulted in utility burner/boiler modifications that frequently yield higher carbon concentrations in fly ash, which restricts the use of the ash as a cement replacement. Controlling ammonia in ash is also of concern. If newer, “clean coal” combustion and gasification technologies are adopted, their byproducts may also present a management challenge. The objective of the Combustion Byproducts Recycling Consortium (CBRC) is to develop and demonstrate technologies to address issues related to the recycling of byproducts associated with coal combustion processes. A goal of CBRC is that these technologies, by the year 2010, will lead to an overall ash utilization rate from the current 34% to 50% by such measures as increasing the current rate of FGD byproduct use and increasing in the number of uses considered “allowable” under state regulations. Another issue of interest to the CBRC would be to examine the environmental impact of both byproduct utilization and disposal. No byproduct utilization technology is likely to be adopted by industry unless it is more cost-effective than landfilling. Therefore, it is extremely important that the utility industry provide guidance to the R&D program. Government agencies and privatesector organizations that may be able to utilize these materials in the conduct of their missions should also provide input. The CBRC will serve as an effective vehicle for acquiring and maintaining guidance from these diverse organizations so that the proper balance in the R&D program is achieved.

  7. Combustion Byproducts Recycling Consortium

    SciTech Connect

    Paul Ziemkiewicz; Tamara Vandivort; Debra Pflughoeft-Hassett; Y. Paul Chugh; James Hower

    2008-08-31

    Each year, over 100 million tons of solid byproducts are produced by coal-burning electric utilities in the United States. Annual production of flue gas desulfurization (FGD) byproducts continues to increase as the result of more stringent sulfur emission restrictions. In addition, stricter limits on NOx emissions mandated by the 1990 Clean Air Act have resulted in utility burner/boiler modifications that frequently yield higher carbon concentrations in fly ash, which restricts the use of the ash as a cement replacement. Controlling ammonia in ash is also of concern. If newer, 'clean coal' combustion and gasification technologies are adopted, their byproducts may also present a management challenge. The objective of the Combustion Byproducts Recycling Consortium (CBRC) is to develop and demonstrate technologies to address issues related to the recycling of byproducts associated with coal combustion processes. A goal of CBRC is that these technologies, by the year 2010, will lead to an overall ash utilization rate from the current 34% to 50% by such measures as increasing the current rate of FGD byproduct use and increasing in the number of uses considered 'allowable' under state regulations. Another issue of interest to the CBRC would be to examine the environmental impact of both byproduct utilization and disposal. No byproduct utilization technology is likely to be adopted by industry unless it is more cost-effective than landfilling. Therefore, it is extremely important that the utility industry provide guidance to the R&D program. Government agencies and private-sector organizations that may be able to utilize these materials in the conduct of their missions should also provide input. The CBRC will serve as an effective vehicle for acquiring and maintaining guidance from these diverse organizations so that the proper balance in the R&D program is achieved.

  8. Apparatus for feeding fluidized bed incinerator, and method of autogenic operation of same

    SciTech Connect

    Nelson, J.F.

    1981-09-29

    This invention relates to an improved method and apparatus for continuous autogenic incineration of high-moisture easily friable combustible agglomerates in a fluidized-bed. The improvement comprises introducing the waste materials into the bed in a tube of air provided by supplemental air means which surrounds the in-bed feed means.

  9. Fly ash facts for highway engineers. Fly ash use in: Concrete base flowable fill structural fill grout paving. Technical report

    SciTech Connect

    1995-08-01

    Coal fly ash is a coal combustion byproduct (CCB) that has numerous applications as a engineering material; the annual production of CCBs is nearly 82 million metric tons (90 million tons). Since the first edition of Fly Ash Facts for Highway Engineers in 1986, substantial information has been accumulated regarding the use of fly ash. The purpose of this document is to provide technical information about engineering applications to potential users of CCBs and to advance the use of CCBs in ways that are technically sound, commercially competitive, and environmentally safe.

  10. Low-rank coal research: Volume 3, Combustion research: Final report. [Great Plains

    SciTech Connect

    Mann, M. D.; Hajicek, D. R.; Zobeck, B. J.; Kalmanovitch, D. P.; Potas, T. A.; Maas, D. J.; Malterer, T. J.; DeWall, R. A.; Miller, B. G.; Johnson, M. D.

    1987-04-01

    Volume III, Combustion Research, contains articles on fluidized bed combustion, advanced processes for low-rank coal slurry production, low-rank coal slurry combustion, heat engine utilization of low-rank coals, and Great Plains Gasification Plant. These articles have been entered individually into EDB and ERA. (LTN)

  11. Turbulent combustion

    SciTech Connect

    Talbot, L.; Cheng, R.K.

    1993-12-01

    Turbulent combustion is the dominant process in heat and power generating systems. Its most significant aspect is to enhance the burning rate and volumetric power density. Turbulent mixing, however, also influences the chemical rates and has a direct effect on the formation of pollutants, flame ignition and extinction. Therefore, research and development of modern combustion systems for power generation, waste incineration and material synthesis must rely on a fundamental understanding of the physical effect of turbulence on combustion to develop theoretical models that can be used as design tools. The overall objective of this program is to investigate, primarily experimentally, the interaction and coupling between turbulence and combustion. These processes are complex and are characterized by scalar and velocity fluctuations with time and length scales spanning several orders of magnitude. They are also influenced by the so-called {open_quotes}field{close_quotes} effects associated with the characteristics of the flow and burner geometries. The authors` approach is to gain a fundamental understanding by investigating idealized laboratory flames. Laboratory flames are amenable to detailed interrogation by laser diagnostics and their flow geometries are chosen to simplify numerical modeling and simulations and to facilitate comparison between experiments and theory.

  12. Advanced expander test bed engine

    NASA Technical Reports Server (NTRS)

    Mitchell, J. P.

    1992-01-01

    The Advanced Expander Test Bed (AETB) is a key element in NASA's Space Chemical Engine Technology Program for development and demonstration of expander cycle oxygen/hydrogen engine and advanced component technologies applicable to space engines as well as launch vehicle upper stage engines. The AETB will be used to validate the high pressure expander cycle concept, study system interactions, and conduct studies of advanced mission focused components and new health monitoring techniques in an engine system environment. The split expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust.

  13. Advanced expander test bed program

    NASA Technical Reports Server (NTRS)

    Masters, A. I.; Mitchell, J. C.

    1991-01-01

    The Advanced Expander Test Bed (AETB) is a key element in NASA's Chemical Transfer Propulsion Program for development and demonstration of expander cycle oxygen/hydrogen engine technology component technology for the next space engine. The AETB will be used to validate the high-pressure expander cycle concept, investigate system interactions, and conduct investigations of advanced missions focused components and new health monitoring techniques. The split-expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust.

  14. Coal devolatilization and char combustion study using FTIR spectroscopy

    SciTech Connect

    Raines, T.S.; Brown, R.C.

    1995-12-31

    The goal of this research is to characterize coals during the normal operation of an industrial-scale circulating fluidized bed (CFB) boiler. The method determines coal properties based on the analysis of transient CO and CO{sub 2} emissions from the boiler. Fourier Transform Infrared (FTIR) spectroscopy is used to qualitatively and quantitatively analyze the gaseous products of combustion. The method is non-intrusive and is performed under realistic combustion conditions. Preliminary data suggest that coal devolatilization is complete before char combustion commences in a circulating fluidized bed boiler.

  15. Combustion Byproducts Recycling Consortium

    SciTech Connect

    Paul Ziemkiewicz; Tamara Vandivort; Debra Pflughoeft-Hassett; Y. Paul Chugh; James Hower

    2008-08-31

    The Combustion Byproducts Recycling Consortium (CBRC) program was developed as a focused program to remove and/or minimize the barriers for effective management of over 123 million tons of coal combustion byproducts (CCBs) annually generated in the USA. At the time of launching the CBRC in 1998, about 25% of CCBs were beneficially utilized while the remaining was disposed in on-site or off-site landfills. During the ten (10) year tenure of CBRC (1998-2008), after a critical review, 52 projects were funded nationwide. By region, the East, Midwest, and West had 21, 18, and 13 projects funded, respectively. Almost all projects were cooperative projects involving industry, government, and academia. The CBRC projects, to a large extent, successfully addressed the problems of large-scale utilization of CCBs. A few projects, such as the two Eastern Region projects that addressed the use of fly ash in foundry applications, might be thought of as a somewhat smaller application in comparison to construction and agricultural uses, but as a novel niche use, they set the stage to draw interest that fly ash substitution for Portland cement might not attract. With consideration of the large increase in flue gas desulfurization (FGD) gypsum in response to EPA regulations, agricultural uses of FGD gypsum hold promise for large-scale uses of a product currently directed to the (currently stagnant) home construction market. Outstanding achievements of the program are: (1) The CBRC successfully enhanced professional expertise in the area of CCBs throughout the nation. The enhanced capacity continues to provide technology and information transfer expertise to industry and regulatory agencies. (2) Several technologies were developed that can be used immediately. These include: (a) Use of CCBs for road base and sub-base applications; (b) full-depth, in situ stabilization of gravel roads or highway/pavement construction recycled materials; and (c) fired bricks containing up to 30%-40% F-fly

  16. Stable Fly Research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adult stable flies feed on the blood of humans, pets and livestock, inflicting painful bites. Stable flies need one and sometimes two bloodmeals each day to develop their eggs. Unlike mosquitoes where only the females bloodfeed, both male and female stable flies require blood to reproduce. Stable fl...

  17. Combustion rates of chars from high-volatile fuels for FBC application

    SciTech Connect

    Masi, S.; Salatino, P.; Senneca, O.

    1997-12-31

    The fluidized bed combustion of high volatile fuels is often associated with huge occurrence of comminution phenomena. These result into in-bed generation of substantial amounts of carbon fines which further undergo competitive processes of combustion and elutriation. The small size of carbon fines generated by comminution is such that their further combustion is largely controlled by the intrinsic kinetics of carbon oxidation, alone or in combination with intraparticle diffusion. The competition between fine combustion and elutriation strongly affects the efficiency of fixed carbon conversion and calls for thorough characterization of the combustion kinetics and of residence times of fines in a fluidized bed of coarse solids. In this paper a collection of intrinsic combustion kinetic and porosimetric data for chars from three high-volatile fuels suitable for FBC application is presented. Chars from a Refuse Derived Fuel (RDF), a Tyre Derived Fuel (TDF) and a biomass (Robinia Pseudoacacia) are obtained from devolatilization, in fluidized bed, of fuel samples. Thermogravimetric analysis, mercury porosimetry and helium pycnometry are used to characterize the reactivity and the pore structure of the chars. Combustion rates are characterized over a wide range of temperatures (320--850 C) and oxygen partial pressures, covering the entire range of interest in fluidized bed combustion. Analysis of thermogravimetric and porosimetric data is directed to obtaining the parameters (pre-exponential factors, reaction orders, activation energies, intraparticle diffusivities) of combustion kinetic submodels for application in fluidized bed combustor modeling.

  18. Regenerative combustion device

    DOEpatents

    West, Phillip B.

    2004-03-16

    A regenerative combustion device having a combustion zone, and chemicals contained within the combustion zone, such as water, having a first equilibrium state, and a second combustible state. Means for transforming the chemicals from the first equilibrium state to the second combustible state, such as electrodes, are disposed within the chemicals. An igniter, such as a spark plug or similar device, is disposed within the combustion zone for igniting combustion of the chemicals in the second combustible state. The combustion products are contained within the combustion zone, and the chemicals are selected such that the combustion products naturally chemically revert into the chemicals in the first equilibrium state following combustion. The combustion device may thus be repeatedly reused, requiring only a brief wait after each ignition to allow the regeneration of combustible gasses within the head space.

  19. Pulse Detonation Engine Test Bed Developed

    NASA Technical Reports Server (NTRS)

    Breisacher, Kevin J.

    2002-01-01

    A detonation is a supersonic combustion wave. A Pulse Detonation Engine (PDE) repetitively creates a series of detonation waves to take advantage of rapid burning and high peak pressures to efficiently produce thrust. NASA Glenn Research Center's Combustion Branch has developed a PDE test bed that can reproduce the operating conditions that might be encountered in an actual engine. It allows the rapid and cost-efficient evaluation of the technical issues and technologies associated with these engines. The test bed is modular in design. It consists of various length sections of both 2- and 2.6- in. internal-diameter combustor tubes. These tubes can be bolted together to create a variety of combustor configurations. A series of bosses allow instrumentation to be inserted on the tubes. Dynamic pressure sensors and heat flux gauges have been used to characterize the performance of the test bed. The PDE test bed is designed to utilize an existing calorimeter (for heat load measurement) and windowed (for optical access) combustor sections. It uses hydrogen as the fuel, and oxygen and nitrogen are mixed to simulate air. An electronic controller is used to open the hydrogen and air valves (or a continuous flow of air is used) and to fire the spark at the appropriate times. Scheduled tests on the test bed include an evaluation of the pumping ability of the train of detonation waves for use in an ejector and an evaluation of the pollutants formed in a PDE combustor. Glenn's Combustion Branch uses the National Combustor Code (NCC) to perform numerical analyses of PDE's as well as to evaluate alternative detonative combustion devices. Pulse Detonation Engine testbed.

  20. Advanced staged combustion system for power generation

    SciTech Connect

    Rehmat, A.; Goyal, A.

    1993-12-31

    To respond to the increasing market need for a new generation of plants with a substantial improvement in efficiency and a reduction in capital cost, the Institute of Gas Technology has developed an advanced staged, fluidized-bed combustion system concept. The staged fluidized-bed partial combustor produces the fuel gas at about 1500 F. The fuel gas, after particulate removal, is directed to a gas turbine followed by a steam cycle. Adequate sulfur capture and solids waste stabilization are attained by separating calcination, carbonization, and gasification/combustion steps in the staged fluidized beds. Intermediate gas cooling is avoided during the process to maximize the power production. The coal-to-electricity conversion efficiency of the system approaches 49 percent, which exceeds the efficiencies of the other emerging technologies.

  1. Advanced Combustion

    SciTech Connect

    Holcomb, Gordon R.

    2013-03-11

    The activity reported in this presentation is to provide the mechanical and physical property information needed to allow rational design, development and/or choice of alloys, manufacturing approaches, and environmental exposure and component life models to enable oxy-fuel combustion boilers to operate at Ultra-Supercritical (up to 650{degrees}C & between 22-30 MPa) and/or Advanced Ultra-Supercritical conditions (760{degrees}C & 35 MPa).

  2. Simulation of fluidized bed coal combustors

    NASA Technical Reports Server (NTRS)

    Rajan, R.

    1979-01-01

    The many deficiencies of previous work on simulation of fluidized bed combustion (FBC) processes are presented. An attempt is made to reduce these deficiencies, and to formulate a comprehensive FBC model taking into account the following elements: (1) devolatilization of coal and the subsequent combustion of volatiles and residual char; (2) sulfur dioxide capture by limestone; (3) NOx release and reduction of NOx by char; (4) attrition and elutriation of char and limestone; (5) bubble hydrodynamics; (6) solids mixing; (7) heat transfer between gas and solid, and solid and heat exchange surfaces; and (8) freeboard reactions.

  3. Design consideration on fuel flexibility of circulating fluidized bed boilers

    SciTech Connect

    Liu, E.H.; Surabian, M.; Haviland, R.W.

    1986-01-01

    This paper examines the inherent differences between a pulverized coal fired unit and a circulating fluidized bed unit, based on fuel properties, ash properties, and characteristics of combustion and heat transfer to determine generic advantages in fuel flexibility of a circulating fluidized bed combustor. This paper also examines how load control and fuel flexibility may be achieved based on the experience Bechtel gained from the first 650,000 pounds per hour circulating fluidized bed boiler project. The conclusion of this paper addresses the economic merits of having flexibility built in during the design phase of a circulating fluidized bed unit.

  4. Reconstructing the behavior of walking fruit flies

    NASA Astrophysics Data System (ADS)

    Berman, Gordon; Bialek, William; Shaevitz, Joshua

    2010-03-01

    Over the past century, the fruit fly Drosophila melanogaster has arisen as almost a lingua franca in the study of animal behavior, having been utilized to study questions in fields as diverse as sleep deprivation, aging, and drug abuse, amongst many others. Accordingly, much is known about what can be done to manipulate these organisms genetically, behaviorally, and physiologically. Most of the behavioral work on this system to this point has been experiments where the flies in question have been given a choice between some discrete set of pre-defined behaviors. Our aim, however, is simply to spend some time with a cadre of flies, using techniques from nonlinear dynamics, statistical physics, and machine learning in an attempt to reconstruct and gain understanding into their behavior. More specifically, we use a multi-camera set-up combined with a motion tracking stage in order to obtain long time-series of walking fruit flies moving about a glass plate. This experimental system serves as a test-bed for analytical, statistical, and computational techniques for studying animal behavior. In particular, we attempt to reconstruct the natural modes of behavior for a fruit fly through a data-driven approach in a manner inspired by recent work in C. elegans and cockroaches.

  5. Fluidization characteristics of power-plant fly ashes and fly ash-charcoal mixtures. [MS Thesis; 40 references

    SciTech Connect

    Nguyen, C.T.

    1980-03-01

    As a part of the continuing research on aluminum recovery from fly ash by HiChlor process, a plexiglass fluidization column system was constructed for measurement of fluidization parameters for power-plant fly ashes and fly ash-charcoal mixtures. Several bituminous and subbituminous coal fly ashes were tested and large differences in fluidization characteristics were observed. Fly ashes which were mechanically collected fluidized uniformly at low gas flow rates. Most fly ashes which were electrostatically precipitated exhibited channeling tendency and did not fluidize uniformly. Fluidization characteristics of electrostatically collected ashes improve when the finely divided charcoal powder is added to the mixture. The fluidization of the mixture was aided initially by a mechanical stirrer. Once the fluidization had succeeded, the beds were ready to fluidize without the assistance of a mechanical action. Smooth fluidization and large bed expansion were usually observed. The effects of charcoal size and aspect ratio on fluidization characteristics of the mixtures were also investigated. Fluidization characteristics of a fly ash-coal mixture were tested. The mixture fluidized only after being oven-dried for a few days.

  6. Packed Bed Reactor Experiment

    NASA Video Gallery

    The purpose of the Packed Bed Reactor Experiment in low gravity is to determine how a mixture of gas and liquid flows through a packed bed in reduced gravity. A packed bed consists of a metal pipe ...

  7. Biomedically relevant chemical and physical properties of coal combustion products.

    PubMed Central

    Fisher, G L

    1983-01-01

    The evaluation of the potential public and occupational health hazards of developing and existing combustion processes requires a detailed understanding of the physical and chemical properties of effluents available for human and environmental exposures. These processes produce complex mixtures of gases and aerosols which may interact synergistically or antagonistically with biological systems. Because of the physicochemical complexity of the effluents, the biomedically relevant properties of these materials must be carefully assessed. Subsequent to release from combustion sources, environmental interactions further complicate assessment of the toxicity of combustion products. This report provides an overview of the biomedically relevant physical and chemical properties of coal fly ash. Coal fly ash is presented as a model complex mixture for health and safety evaluation of combustion processes. PMID:6337824

  8. Fluidized bed heat exchanger with water cooled air distributor and dust hopper

    DOEpatents

    Jukkola, Walfred W.; Leon, Albert M.; Van Dyk, Jr., Garritt C.; McCoy, Daniel E.; Fisher, Barry L.; Saiers, Timothy L.; Karstetter, Marlin E.

    1981-11-24

    A fluidized bed heat exchanger is provided in which air is passed through a bed of particulate material containing fuel. A steam-water natural circulation system is provided for heat exchange and the housing of the heat exchanger has a water-wall type construction. Vertical in-bed heat exchange tubes are provided and the air distributor is water-cooled. A water-cooled dust hopper is provided in the housing to collect particulates from the combustion gases and separate the combustion zone from a volume within said housing in which convection heat exchange tubes are provided to extract heat from the exiting combustion gases.

  9. The recycling of the coal fly ash in glass production

    SciTech Connect

    Erol, M.M.; Kucukbayrak, S.; Ersoy-Mericboyu, A.

    2006-09-15

    The recycling of fly ash obtained from the combustion of coal in thermal power plant has been studied. Coal fly ash was vitrified by melting at 1773 K for 5 hours without any additives. The properties of glasses produced from coal fly ash were investigated by means of Differential Thermal Analysis (DTA), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) techniques. DTA study indicated that there was only one endothermic peak at 1003 K corresponding to the glass transition temperature. XRD analysis showed the amorphous state of the glass sample produced from coal fly ash. SEM investigations revealed that the coal fly ash based glass sample had smooth surface. The mechanical, physical and chemical properties of the glass sample were also determined. Recycling of coal fly ash by using vitrification technique resulted to a glass material that had good mechanical, physical and chemical properties. Toxicity characteristic leaching procedure (TCLP) results showed that the heavy metals of Pb, Cr, Zn and Mn were successfully immobilized into the glass. It can be said that glass sample obtained by the recycling of coal fly ash can be taken as a non-hazardous material. Overall, results indicated that the vitrification technique is an effective way for the stabilization and recycling of coal fly ash.

  10. Fly ash carbon passivation

    DOEpatents

    La Count, Robert B; Baltrus, John P; Kern, Douglas G

    2013-05-14

    A thermal method to passivate the carbon and/or other components in fly ash significantly decreases adsorption. The passivated carbon remains in the fly ash. Heating the fly ash to about 500 and 800 degrees C. under inert gas conditions sharply decreases the amount of surfactant adsorbed by the fly ash recovered after thermal treatment despite the fact that the carbon content remains in the fly ash. Using oxygen and inert gas mixtures, the present invention shows that a thermal treatment to about 500 degrees C. also sharply decreases the surfactant adsorption of the recovered fly ash even though most of the carbon remains intact. Also, thermal treatment to about 800 degrees C. under these same oxidative conditions shows a sharp decrease in surfactant adsorption of the recovered fly ash due to the fact that the carbon has been removed. This experiment simulates the various "carbon burnout" methods and is not a claim in this method. The present invention provides a thermal method of deactivating high carbon fly ash toward adsorption of AEAs while retaining the fly ash carbon. The fly ash can be used, for example, as a partial Portland cement replacement in air-entrained concrete, in conductive and other concretes, and for other applications.

  11. Oil shale retorting and combustion system

    DOEpatents

    Pitrolo, Augustine A.; Mei, Joseph S.; Shang, Jerry Y.

    1983-01-01

    The present invention is directed to the extraction of energy values from l shale containing considerable concentrations of calcium carbonate in an efficient manner. The volatiles are separated from the oil shale in a retorting zone of a fluidized bed where the temperature and the concentration of oxygen are maintained at sufficiently low levels so that the volatiles are extracted from the oil shale with minimal combustion of the volatiles and with minimal calcination of the calcium carbonate. These gaseous volatiles and the calcium carbonate flow from the retorting zone into a freeboard combustion zone where the volatiles are burned in the presence of excess air. In this zone the calcination of the calcium carbonate occurs but at the expense of less BTU's than would be required by the calcination reaction in the event both the retorting and combustion steps took place simultaneously. The heat values in the products of combustion are satisfactorily recovered in a suitable heat exchange system.

  12. Oxy-coal Combustion Studies

    SciTech Connect

    Wendt, J.; Eddings, E.; Lighty, J.; Ring, T.; Smith, P.; Thornock, J.; Y Jia, W. Morris; Pedel, J.; Rezeai, D.; Wang, L.; Zhang, J.; Kelly, K.

    2012-01-06

    The objective of this project is to move toward the development of a predictive capability with quantified uncertainty bounds for pilot-scale, single-burner, oxy-coal operation. This validation research brings together multi-scale experimental measurements and computer simulations. The combination of simulation development and validation experiments is designed to lead to predictive tools for the performance of existing air fired pulverized coal boilers that have been retrofitted to various oxy-firing configurations. In addition, this report also describes novel research results related to oxy-combustion in circulating fluidized beds. For pulverized coal combustion configurations, particular attention is focused on the effect of oxy-firing on ignition and coal-flame stability, and on the subsequent partitioning mechanisms of the ash aerosol.

  13. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    SciTech Connect

    Not Available

    1992-02-01

    The objective of this DOE Cooperative Agreement is to conduct a cost-shared clean coal technology project to demonstrate the feasibility of circulating fluidized bed combustion technology and to evaluate economic, environmental, and operational benefits of CFB steam generators on a utility scale. At the conclusion of the Phase 2 program, testing related to satisfying these objectives was completed. Data analysis and reporting are scheduled for completion by October 1991. (VC)

  14. Anthracite culm fired fluidized-bed boiler

    SciTech Connect

    Lentz, E.C.

    1984-01-01

    The author describes a fluidised-bed boiler that has been designed by FluiDyne Engineering Corp. for the combustion of anthracite culm, a material containing about 40% ash and consisting of coal particles embedded in mineral matter. There are some 900 million tons of anthracite culm in northeast Pennsylvania within easy reach of many large metropolitan areas. It is estimated that the material can be used economically within a distance of 200 miles.

  15. Coal combustion and heavy metals pollution

    SciTech Connect

    Danihelka, P.; Ochodek, T.; Borovec, K.

    1996-12-31

    Combustion of coal may be an important source of heavy metals pollution. The major environmental risks of heavy metals are connected to their toxicity and mobility in the environment. In the flame, heavy metals are re-distributed with respect to their volatility. Enrichment of fine particles by volatile metals is the most important mechanism for most of the metals. Nevertheless, Hg is emitted mainly in gaseous form and some metals like Mn are concentrated rather in coarse particles. Heavy metals pollution caused by emissions from combustion of coal may be decreased by fine particles removal; other possibilities (metals extraction from the coal, changes of condition in the flame) are limited. Fly ashes from the most important Czech power plants were examined with respect to the heavy metals content. The easily leachable elements with high volatility in the flame (arsenic, zinc, lead) were recognized as the most important fly ash pollutants. The average concentrations of these metals in fly ash were: bituminous coal 46{+-}18 ppm As, 196{+-}93 ppm Zn, 126{+-}46 ppm Pb; brown coal 283{+-}260 ppm As, 60{+-}28 ppm Pb and 212{+-}116 ppm Zn. When ESP and cyclones are used in series, fly ashes from ESP have higher concentration of volatile heavy metals, mainly Pb, Zn and As. Presence of chlorine in fuel increases the volatility of metals.

  16. Relationships between composition and pulmonary toxicity of prototype particles from coal combustion and pyrolysis

    EPA Science Inventory

    The hypothesis that health effects associated with coal combustion fly-ash particles are exacerbated by the simultaneous presence of iron and soot was tested through two sets of experiments. The first set created prototype particles from complete and partial combustion, or oxygen...

  17. RELATIONSHIPS BETWEEN COMPOSITION AND PULMONARY TOXICITY OF PROTOTYPE PARTICLES FROM COAL COMBUSTION AND PYROLYSIS (MONTREAL, CANADA)

    EPA Science Inventory

    The hypothesis that health effects associated with coal combustion fly-ash particles are exacerbated by the simultaneous presence of iron and soot was tested through two sets of experiments. The first set created prototype particles from complete and partial combustion, or oxygen...

  18. Soot, organics, and ultrafine ash from air- and oxy-fired coal combustion

    EPA Science Inventory

    This paper/presentation is concerned with determining the effects of oxy-combustion of coal on the composition of the ultrafine fly ash. To this end, a 10 W externally heated entrained flow furnace was modified to allow the combustion of pulverized coal in flames under practicall...

  19. Pulsed atmospheric fluidized bed combustor apparatus and process

    DOEpatents

    Mansour, Momtaz N.

    1992-01-01

    A pulsed atmospheric fluidized bed reactor system is disclosed and claimed along with a process for utilization of same for the combustion of, e.g. high sulfur content coal. The system affords a economical, ecologically acceptable alternative to oil and gas fired combustors. The apparatus may also be employed for endothermic reaction, combustion of waste products, e.g. organic and medical waste, drying, calcining and the like.

  20. Bi-Component Droplet Combustion Experiment Designed

    NASA Technical Reports Server (NTRS)

    Dietrich, Daniel L.

    2002-01-01

    The combustion of liquid fuels is a major source of energy in the world today, and the majority of these fuels are burned in the form of a spray. The research at the NASA Glenn Research Center in droplet combustion has the overall goal of providing a better understanding of spray combustion by studying the smallest element in a spray, the single droplet. The Bi-Component Droplet Combustion Experiment (BCDCE) extends the work at Glenn from pure, or single-component, fuels to an idealized liquid fuel composed of two completely miscible components. The project is a collaborative effort between Glenn and Prof. B.D. Shaw of the University of California, Davis. The BCDCE project is planned to fly onboard the International Space Station in the Multi-User Droplet Combustion Apparatus. The unique feature of this experiment is that it will be the first droplet combustion experiment to perform a detailed characterization of the flow inside a liquid fuel droplet. The experiment will use a relatively new technique called Digital Particle Imaging Velocimetry (DPIV) to characterize the liquid flow. In this technique, very small (approx. 5-mm diameter) particles are dispersed throughout a liquid droplet. These particles are illuminated by a thin laser sheet. Images of the particle motion are recorded on a computer, which then tracks the motion of the particles to determine the flow characteristics.

  1. AFBC bed material performance with low-rank coals

    SciTech Connect

    Goblirsch, G.M.; Benson, S.A.; Karner, F.R.; Rindt, D.K.; Hajicek, D.R.

    1983-01-01

    The purpose of this paper is to describe the reasons for carefully screening any candidate bed material for use in low-rank coal atmospheric fluidized-bed combustion, before the final selection is made. The sections of this paper describe: (1) the experimental equipment used to obtain the data, as well as the experimental and analytical procedures used in evaluation; (2) the results of tests utilizing various bed materials with particular emphasis on the problem of bed material agglomeration; and (3) the conclusions and recommendations for bed material selection and control for use with low-rank coal. Bed materials of aluminum oxide, quartz, limestone, dolomite, granite, gabbro, and mixtures of some of these materials have been used in the testing. Of these materials, gabbro appears most suitable for use with high available sodium lignites. 17 figures, 8 tables. (DMC)

  2. Study of swirling gas-dispersed flows in vortex chambers of various structures in the presence and absence of combustion

    NASA Astrophysics Data System (ADS)

    Volchkov, É. P.; Dvornikov, N. A.; Lukashov, V. V.; Borodulya, V. A.; Teplitskii, Yu. S.; Pitsukha, E. A.

    2012-07-01

    Consideration is given to swirling gas-dispersed flows in the cylindrical combustion chamber with a lateral swirler, in the conical combustion chamber with a nonflow bed of a dispersed material, and in the cylindrical combustion chamber with lower end injection of the gas through a slot swirler.

  3. Use of Fly Ash as a Liming Material for Corn and Soybean Production on an Acidic Sandy Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fly ash (FA) produced from subbituminous coal combustion can potentially serve as a lime material for crop production in acidic soils in areas. A five-year study was conducted to determine if FA can be used as a liming material in an acid sandy soil under corn and soybean grain production. Fly ash...

  4. KINETIC STUDY OF ADSORPTION AND TRANSFORMATION OF MERCURY ON FLY ASH PARTICLES IN AN ENTRAINED FLOW REACTOR

    EPA Science Inventory

    Experimental studies were performed to investigate the interactions of elemental mercury vapor with entrained fly ash particles from coal combustion in a flow reactor. The rate of transformation of elemental mercury on fly ash particles was evauated over the temperature range fro...

  5. Combustion chemistry

    SciTech Connect

    Brown, N.J.

    1993-12-01

    This research is concerned with the development and use of sensitivity analysis tools to probe the response of dependent variables to model input variables. Sensitivity analysis is important at all levels of combustion modeling. This group`s research continues to be focused on elucidating the interrelationship between features in the underlying potential energy surface (obtained from ab initio quantum chemistry calculations) and their responses in the quantum dynamics, e.g., reactive transition probabilities, cross sections, and thermal rate coefficients. The goals of this research are: (i) to provide feedback information to quantum chemists in their potential surface refinement efforts, and (ii) to gain a better understanding of how various regions in the potential influence the dynamics. These investigations are carried out with the methodology of quantum functional sensitivity analysis (QFSA).

  6. DEVELOPMENT OF ACTIVATED CARBONS FROM COAL COMBUSTION BY-PRODUCTS

    SciTech Connect

    Harold H. Schobert; M. Mercedes Maroto-Valer; Zhe Lu

    2003-09-30

    The increasing role of coal as a source of energy in the 21st century will demand environmental and cost-effective strategies for the use of coal combustion by-products (CCBPs), mainly unburned carbon in fly ash. Unburned carbon is nowadays regarded as a waste product and its fate is mainly disposal, due to the present lack of efficient routes for its utilization. However, unburned carbon is a potential precursor for the production of adsorbent carbons, since it has gone through a devolatilization process while in the combustor, and therefore, only requires to be activated. Accordingly, the principal objective of this work was to characterize and utilize the unburned carbon in fly ash for the production of activated carbons. The unburned carbon samples were collected from different combustion systems, including pulverized utility boilers, a utility cyclone, a stoker, and a fluidized bed combustor. LOI (loss-on-ignition), proximate, ultimate, and petrographic analyses were conducted, and the surface areas of the samples were characterized by N2 adsorption isotherms at 77K. The LOIs of the unburned carbon samples varied between 21.79-84.52%. The proximate analyses showed that all the samples had very low moisture contents (0.17 to 3.39 wt %), while the volatile matter contents varied between 0.45 to 24.82 wt%. The elemental analyses show that all the unburned carbon samples consist mainly of carbon with very little hydrogen, nitrogen, sulfur and oxygen In addition, the potential use of unburned carbon as precursor for activated carbon (AC) was investigated. Activated carbons with specific surface area up to 1075m{sup 2}/g were produced from the unburned carbon. The porosity of the resultant activated carbons was related to the properties of the unburned carbon feedstock and the activation conditions used. It was found that not all the unburned carbon samples are equally suited for activation, and furthermore, their potential as activated carbons precursors could be

  7. A Flying Summer Camp

    ERIC Educational Resources Information Center

    Mercurio, Frank X.

    1975-01-01

    Describes a five-day summer camp which provided 12 children, ages 9-14, with a complete flying experience. The training consisted of ground school and one hour actual flying time, including the basics of aircraft control and a flight prepared and executed by the students. (MLH)

  8. Activation of fly ash

    DOEpatents

    Corbin, D.R.; Velenyi, L.J.; Pepera, M.A.; Dolhyj, S.R.

    1986-08-19

    Fly ash is activated by heating a screened magnetic fraction of the ash in a steam atmosphere and then reducing, oxidizing and again reducing the hydrothermally treated fraction. The activated fly ash can be used as a carbon monoxide disproportionating catalyst useful in the production of hydrogen and methane.

  9. Ever Fly a Tetrahedron?

    ERIC Educational Resources Information Center

    King, Kenneth

    2004-01-01

    Few things capture the spirit of spring like flying a kite. Watching a kite dance and sail across a cloud spotted sky is not only a visually appealing experience it also provides a foundation for studies in science and mathematics. Put simply, a kite is an airfoil surface that flies when the forces of lift and thrust are greater than the forces of…

  10. Activation of fly ash

    DOEpatents

    Corbin, David R.; Velenyi, Louis J.; Pepera, Marc A.; Dolhyj, Serge R.

    1986-01-01

    Fly ash is activated by heating a screened magnetic fraction of the ash in a steam atmosphere and then reducing, oxidizing and again reducing the hydrothermally treated fraction. The activated fly ash can be used as a carbon monoxide disproportionating catalyst useful in the production of hydrogen and methane.

  11. 7 CFR 2902.15 - Bedding, bed linens, and towels.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Bedding, bed linens, and towels. 2902.15 Section 2902... PROCUREMENT Designated Items § 2902.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that..., bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding....

  12. 7 CFR 3201.15 - Bedding, bed linens, and towels.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Bedding, bed linens, and towels. 3201.15 Section 3201... PROCUREMENT Designated Items § 3201.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that..., bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding....

  13. 7 CFR 3201.15 - Bedding, bed linens, and towels.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Bedding, bed linens, and towels. 3201.15 Section 3201... PROCUREMENT Designated Items § 3201.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that..., bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding....

  14. 7 CFR 2902.15 - Bedding, bed linens, and towels.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Bedding, bed linens, and towels. 2902.15 Section 2902... PROCUREMENT Designated Items § 2902.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that..., bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding....

  15. 7 CFR 3201.15 - Bedding, bed linens, and towels.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Bedding, bed linens, and towels. 3201.15 Section 3201... PROCUREMENT Designated Items § 3201.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that..., bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding....

  16. Solid fuel combustion system for gas turbine engine

    DOEpatents

    Wilkes, Colin; Mongia, Hukam C.

    1993-01-01

    A solid fuel, pressurized fluidized bed combustion system for a gas turbine engine includes a carbonizer outside of the engine for gasifying coal to a low Btu fuel gas in a first fraction of compressor discharge, a pressurized fluidized bed outside of the engine for combusting the char residue from the carbonizer in a second fraction of compressor discharge to produce low temperature vitiated air, and a fuel-rich, fuel-lean staged topping combustor inside the engine in a compressed air plenum thereof. Diversion of less than 100% of compressor discharge outside the engine minimizes the expense of fabricating and maintaining conduits for transferring high pressure and high temperature gas and incorporation of the topping combustor in the compressed air plenum of the engine minimizes the expense of modifying otherwise conventional gas turbine engines for solid fuel, pressurized fluidized bed combustion.

  17. Reduction of carbon content in waste-tire combustion ashes by bio-thermal treatment

    SciTech Connect

    Chen, C.C.; Lee, W.J.; Shih, S.I.; Mou, J.L.

    2009-07-01

    Application of bio-catalyst (NOE-7F) in thermal treatment can adequately dispose dark-black fly ashes from co-combustion of both waste tires and coal. After thermal treatment of fly ashes by adding 10% NOE-7F, the carbon contents reduced by 37.6% and the weight losses increased by 405%, compared with the fly ashes without mixing with NOE-7F. The combustion behaviors of wasted tires combustion fly ashes with NOE-7F were also investigated by both thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The results verify that NOE-7F has positive effects on the combustion of residual carbon and toxic polycyclic aromatic hydrocarbons (PAHs) enhance the energy release and reduce the toxicity during the process of thermal treatment. Furthermore, using NOE-7F to dispose high-carbon content fly ashes did improve the compressive strength of fly ashes and concrete mixtures. Therefore, NOE-7F is a promising additive which could decrease treatment cost of high-carbon content fly ashes and reduce the amount of survival toxic PAHs.

  18. Combustion Fundamentals Research

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Increased emphasis is placed on fundamental and generic research at Lewis Research Center with less systems development efforts. This is especially true in combustion research, where the study of combustion fundamentals has grown significantly in order to better address the perceived long term technical needs of the aerospace industry. The main thrusts for this combustion fundamentals program area are as follows: analytical models of combustion processes, model verification experiments, fundamental combustion experiments, and advanced numeric techniques.

  19. Coal combustion science

    SciTech Connect

    Hardesty, D.R.; Baxter, L.L.; Fletcher, T.H.; Mitchell, R.E.

    1990-11-01

    The objective of this activity is to support the Office of Fossil Energy in executing research on coal combustion science. This activity consists of basic research on coal combustion that supports both the Pittsburgh Energy Technology Center (PETC) Direct Utilization Advanced Research and Technology Development Program, and the International Energy Agency (IEA) Coal Combustion Science Project. Specific tasks include: coal devolatilization, coal char combustion, and fate of mineral matter during coal combustion. 91 refs., 40 figs., 9 tabs.

  20. Study on Type C Coal Fly ash as an Additive to Molding Sand for Steel Casting

    NASA Astrophysics Data System (ADS)

    Palaniappan, Jayanthi

    2017-04-01

    Study of physio-chemical properties studies such as granulometric analysis, moisture, X ray fluorescence etc. were performed with Type C coal—combustion fly ash to investigate their potential as a distinct option for molding sand in foundry, thereby reducing the dependency on latter. Technological properties study such as compressive strength, tensile strength, permeability and compaction of various compositions of fly ash molding sand (10, 20 and 30 % fly ash substitute to chemically bonded sand) were performed and compared with silica molding sand. Steel casting production using this fly ash molding sand was done and the casting surface finish and typical casting parameters were assessed. It was noted that a good quality steel casting could be produced using type C fly ash molding sand, which effectively replaced 20 % of traditional molding sand and binders thereby providing greater financial profits to the foundry and an effective way of fly ash utilization (waste management).

  1. Study on Type C Coal Fly ash as an Additive to Molding Sand for Steel Casting

    NASA Astrophysics Data System (ADS)

    Palaniappan, Jayanthi

    2016-05-01

    Study of physio-chemical properties studies such as granulometric analysis, moisture, X ray fluorescence etc. were performed with Type C coal—combustion fly ash to investigate their potential as a distinct option for molding sand in foundry, thereby reducing the dependency on latter. Technological properties study such as compressive strength, tensile strength, permeability and compaction of various compositions of fly ash molding sand (10, 20 and 30 % fly ash substitute to chemically bonded sand) were performed and compared with silica molding sand. Steel casting production using this fly ash molding sand was done and the casting surface finish and typical casting parameters were assessed. It was noted that a good quality steel casting could be produced using type C fly ash molding sand, which effectively replaced 20 % of traditional molding sand and binders thereby providing greater financial profits to the foundry and an effective way of fly ash utilization (waste management).

  2. Combustible particluate fuel heater

    SciTech Connect

    Collins, B.H.; Jurgens, H.J.W.

    1986-01-21

    This patent describes a combustible particulate fired heater. It consists of: a combustion chamber defined by upright side walls extending between open top and bottom ends; an enclosure surrounding the combustion chamber; a retort within the combustion chamber adjacent the bottom end and having a lower particulate receiving end and an upper open end; feed conveyor means leading through the enclosure to the retort for delivering metered quantities of combustible particulates to the lower particulate receiving end of the retort; primary combustion air supply means having a primary combustion air supply manifold extending at least partially about the upper open end of the retort; primary air control means on the primary air supply means for selectively allowing entry of combustion air from outside the enclosure in to the retort; secondary combustion air supply means including a secondary air supply manifold within the combustion chamber above the primary combustion air supply manifold; secondary air control means independent of the primary air control means for selectively allowing entry of secondary air from outside the enclosure to an area within the combustion chamber above the retort; an exhaust duct opening into the enclosure; and vacuum means connected to the exhaust duct for producing a pressure differential between the area confined by the enclosure and the ambient atmosphere such that ambient air is drawn through at least one of the combustion air supply means to induce a high level of gasification and to support combustion at the retort and for drawing combustion exhaust gases out through the exhaust duct.

  3. Advanced expander test bed program

    NASA Technical Reports Server (NTRS)

    Riccardi, D. P.; Mitchell, J. C.

    1993-01-01

    The Advanced Expander Test Bed (AETB) is a key element in NASA's Space Chemical Engine Technology Program for development and demonstration of expander cycle oxygen/hydrogen engine and advanced component technologies applicable to space engines as well as launch vehicle upper stage engines. The AETB will be used to validate the high-pressure expander cycle concept, investigate system interactions, and conduct investigations of advanced mission focused components and new health monitoring techniques in an engine system environment. The split expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust. Contract work began 27 Apr. 1990. During 1992, a major milestone was achieved with the review of the final design of the oxidizer turbopump in Sep. 1992.

  4. Combustion technologies

    SciTech Connect

    Barsin, J.A.

    1994-12-31

    The presentation will cover the highlights of sludge, providing information as to where it comes from, projection of how much more is expected, what is sludge, what can be done with them, and finally focus in one combustion technology that can be utilized and applied to recycle sludge. The author is with Gotaverken Energy Systems Inc. where for the past 100 years they have been involved in the recovery of chemicals in chemical pulp mills. One week ago, our name was changed to Kvaerner Pulping Inc. to better reflect our present make-up which is a combination of Kamyr AB (suppliers of proprietary highly engineered totally chlorine free chemical pulp manufacturing systems, including digesters, O{sub 2} delignification systems, and bleach plant systems) and Goetaverken. Sludges that we are concerned with derive from several sources within chemical pulp mills such as: such as primary clarifier sludges, secondary clarifier sludges, and most recently those sludges derived from post consumer paper and board recycle efforts including de-inking and those from the thermal mechanical pulping processes. These sludges have been classified as non-hazardous therefore, residue can be landfilled, but the volumes involved are growing at an alarming rate.

  5. Combustion of Australian spent shales compared

    SciTech Connect

    Not Available

    1986-12-01

    The combustion kinetics of spent oil shales from seven major Australian deposits have been examined using a fluidized bed batch technique. Chemical rate constants were shown to vary between the shales and to be less than extrapolations of data from American spent oil shales. The effective diffusivity also varies widely among the shales. The seven oil shales were from the Condor, Duaringa, Lowmead, Nagoorin, Nagoorin South, Rundle and Stuart deposits in Queensland. Results are briefly described. 1 figure, 1 table.

  6. Bed Bugs and Schools

    EPA Pesticide Factsheets

    Bed bugs have long been a pest – feeding on blood, causing itchy bites and generally irritating their human hosts. They are successful hitchhikers, and can move from an infested site to furniture, bedding, baggage, boxes, and clothing.

  7. Bed rest during pregnancy

    MedlinePlus

    ... on the inferior vena cava. How Can I Deal with Discomfort from Bed Rest? Bed rest can ... Group Health Cooperative, Bellevue, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the ...

  8. Experimental Replication of an Aeroengine Combustion Instability

    NASA Technical Reports Server (NTRS)

    Cohen, J. M.; Hibshman, J. R.; Proscia, W.; Rosfjord, T. J.; Wake, B. E.; McVey, J. B.; Lovett, J.; Ondas, M.; DeLaat, J.; Breisacher, K.

    2000-01-01

    Combustion instabilities in gas turbine engines are most frequently encountered during the late phases of engine development, at which point they are difficult and expensive to fix. The ability to replicate an engine-traceable combustion instability in a laboratory-scale experiment offers the opportunity to economically diagnose the problem (to determine the root cause), and to investigate solutions to the problem, such as active control. The development and validation of active combustion instability control requires that the causal dynamic processes be reproduced in experimental test facilities which can be used as a test bed for control system evaluation. This paper discusses the process through which a laboratory-scale experiment was designed to replicate an instability observed in a developmental engine. The scaling process used physically-based analyses to preserve the relevant geometric, acoustic and thermo-fluid features. The process increases the probability that results achieved in the single-nozzle experiment will be scalable to the engine.

  9. Introduction to Bed Bugs

    EPA Pesticide Factsheets

    The common bed bug (Cimex lectularius) is a pest – feeding on blood, causing itchy bites and generally irritating their human hosts. EPA and other agencies all consider bed bugs a public health pest, but bed bugs are not known to transmit disease.

  10. Making a Bed

    ERIC Educational Resources Information Center

    Wexler, Anthony; Stein, Sherman

    2005-01-01

    The origins of this paper lay in making beds by putting pieces of plywood on a frame: If beds need to be 4 feet 6 inches by 6 feet 3 inches, and plywood comes in 4-foot by 8-foot sheets, how should one cut the plywood to minimize waste (and have stable beds)? The problem is of course generalized.

  11. Some features of the technology for thermochemical reprocessing of coals in a circulating fluidized bed

    NASA Astrophysics Data System (ADS)

    Rokhman, B. B.

    2007-06-01

    Results from theoretical investigations into transfer processes during the combustion of anthracite culm in a circulating fluidized bed furnace are presented. A method is described according to which hot air is separately admitted into the furnace: the primary air, to under the fluidized-bed grate, and the secondary air, to over its upper boundary. Calculation results together with their discussion are presented.

  12. Combustion 2000

    SciTech Connect

    2000-06-30

    This report presents work carried out under contract DE-AC22-95PC95144 ''Combustion 2000 - Phase II.'' The goals of the program are to develop a coal-fired high performance power generation system (HIPPS) that is capable of: {lg_bullet} thermal efficiency (HHV) {ge} 47% {lg_bullet} NOx, SOx, and particulates {le} 10% NSPS (New Source Performance Standard) {lg_bullet} coal providing {ge} 65% of heat input {lg_bullet} all solid wastes benign {lg_bullet} cost of electricity {le} 90% of present plants Phase I, which began in 1992, focused on the analysis of various configurations of indirectly fired cycles and on technical assessments of alternative plant subsystems and components, including performance requirements, developmental status, design options, complexity and reliability, and capital and operating costs. Phase I also included preliminary R&D and the preparation of designs for HIPPS commercial plants approximately 300 MWe in size. Phase II, had as its initial objective the development of a complete design base for the construction and operation of a HIPPS prototype plant to be constructed in Phase III. As part of a descoping initiative, the Phase III program has been eliminated and work related to the commercial plant design has been ended. The rescoped program retained a program of engineering research and development focusing on high temperature heat exchangers, e.g. HITAF development (Task 2); a rescoped Task 6 that is pertinent to Vision 21 objectives and focuses on advanced cycle analysis and optimization, integration of gas turbines into complex cycles, and repowering designs; and preparation of the Phase II Technical Report (Task 8). This rescoped program deleted all subsystem testing (Tasks 3, 4, and 5) and the development of a site specific engineering design and test plan for the HIPPS prototype plant (Task 7). Work reported herein is from: {lg_bullet} Task 2.2.4 Pilot Scale Testing {lg_bullet} Task 2.2.5.2 Laboratory and Bench Scale Activities

  13. Combustion 2000

    SciTech Connect

    A. Levasseur; S. Goodstine; J. Ruby; M. Nawaz; C. Senior; F. Robson; S. Lehman; W. Blecher; W. Fugard; A. Rao; A. Sarofim; P. Smith; D. Pershing; E. Eddings; M. Cremer; J. Hurley; G. Weber; M. Jones; M. Collings; D. Hajicek; A. Henderson; P. Klevan; D. Seery; B. Knight; R. Lessard; J. Sangiovanni; A. Dennis; C. Bird; W. Sutton; N. Bornstein; F. Cogswell; C. Randino; S. Gale; Mike Heap

    2001-06-30

    . To achieve these objectives requires a change from complete reliance of coal-fired systems on steam turbines (Rankine cycles) and moving forward to a combined cycle utilizing gas turbines (Brayton cycles) which offer the possibility of significantly greater efficiency. This is because gas turbine cycles operate at temperatures well beyond current steam cycles, allowing the working fluid (air) temperature to more closely approach that of the major energy source, the combustion of coal. In fact, a good figure of merit for a HIPPS design is just how much of the enthalpy from coal combustion is used by the gas turbine. The efficiency of a power cycle varies directly with the temperature of the working fluid and for contemporary gas turbines the optimal turbine inlet temperature is in the range of 2300-2500 F (1260-1371 C). These temperatures are beyond the working range of currently available alloys and are also in the range of the ash fusion temperature of most coals. These two sets of physical properties combine to produce the major engineering challenges for a HIPPS design. The UTRC team developed a design hierarchy to impose more rigor in our approach. Once the size of the plant had been determined by the choice of gas turbine and the matching steam turbine, the design process of the High Temperature Advanced Furnace (HITAF) moved ineluctably to a down-fired, slagging configuration. This design was based on two air heaters: one a high temperature slagging Radiative Air Heater (RAH) and a lower temperature, dry ash Convective Air Heater (CAH). The specific details of the air heaters are arrived at by an iterative sequence in the following order:-Starting from the overall Cycle requirements which set the limits for the combustion and heat transfer analysis-The available enthalpy determined the range of materials, ceramics or alloys, which could tolerate the temperatures-Structural Analysis of the designs proved to be the major limitation-Finally the commercialization

  14. Evaluation of interactions between soil and coal fly ash leachates using column percolation tests.

    PubMed

    Tsiridis, V; Petala, M; Samaras, P; Sakellaropoulos, G P

    2015-09-01

    The aim of this work was the assessment of the environmental impact of different origin fly ashes with regard to their final disposal. The experimental procedure included the performance of single column tests and column tests of fly ash and soil in series. The appraisal of the potential environmental hazards was implemented using physicochemical analyses and bioassays. Two different fly ash samples were examined, one fly ash produced from the combustion of sub-bituminous coal (CFA) and one fly ash produced from the combustion of lignite (LFA). Single column percolation tests were performed according to NEN 7343 protocol, while fly ash/soil experiments were conducted incorporating slight modifications to this protocol. The study focused on the release of metals Ba, Cr, Cu, Mo, Se and Zn and the ecotoxic behavior of leachates on crustacean Daphnia magna and bacteria Vibrio fischeri. The infiltration of the leachates of both fly ashes through soil affected considerably their leaching profile. The transport of Cu and Zn was facilitated by the dynamic leaching conditions and influenced by the pH of the leachates. Moreover, the release and bioavailability of Cr, Cu and Zn was probably altered during the infiltration experiments and organisms' response was not always correlated with the concentration of metals. Nevertheless, the results are signalling that possible manipulations and final disposal of fly ash should be considered when environmental threats are investigated.

  15. Reburning Characteristics of Residual Carbon in Fly Ash from CFB Boilers

    NASA Astrophysics Data System (ADS)

    Zhang, S. H.; Luo, H. H.; Chen, H. P.; Yang, H. P.; Wang, X. H.

    The content of residual carbon in fly ash of CFB boilers is a litter high especially when low-grade coal, such as lean coal, anthracite coal, gangue, etc. is in service, which greatly influences the efficiency of boilers and fly ash further disposal. Reburn of fly ash through collection, recirculation in CFB furnace or external combustor is a possibly effective strategy to decrease the carbon content, mainly depending on the residual carbon reactivity. In this work, the combustion properties of residual carbon in fly ash and corresponding original coal from large commercial CFB boilers (Kaifeng (440t/h), and Fenyi (410t/h), all in china) are comparably investigated through experiments. The residual carbon involved was firstly extracted and enriched from fly ash by means of floating elutriation to mitigate the influence of ash and minerals on the combustion behavior of residual carbon. Then, the combustion characteristic of two residual carbons and the original coal particles was analyzed with thermogravimetric analyzer (TGA, STA409C from Nestch, Germany). It was observed that the ignition temperature of the residual carbon is much higher than that of original coal sample, and the combustion reactivity of residual carbon is not only dependent on the original coal property, but also the operating conditions. The influence of oxygen content and heating rate was also studied in TGA. The O2 concentration is set as 20%, 30%, 40% and 70% respectively in O2/N2 gas mixture with the flow rate of 100ml/min. It was found that higher oxygen content is favor for decreasing ignition temperature, accelerating the combustion rate of residual carbon. And about 40% of oxygen concentration is experimentally suggested as an optimal value when oxygen-enriched combustion is put into practice for decreasing residual carbon content of fly ash in CFB boilers.

  16. Sludge incineration in a spinning fluidized bed incinerator

    SciTech Connect

    Swithenbank, J.; Basire, S.; Wong, W.Y.; Lu, Y.; Nasserzadeh, V.

    1999-07-01

    At the present time, the sewage treatment plants in the UK produce about 25 million tonnes of sewage sludge each year at a concentration of 4% solids. New regulations forbid sea dumping and in the near future new incinerators will be required to dispose of about five million tonnes per year. Bubbling fluidized bed incinerators are widely used to burn sewage sludge at a typical consumption rate of about 0.02 kg(dry)/s/m{sup 2}, and it follows that over 300 conventional fluidized bed incinerators of 3 meters bed diameter could be required to cope with the increased demand. At Sheffield University Waste Incineration Centre (SUWIC) research work is being carried out to develop a novel spinning fluidized bed incinerator. The key factor to note is that when air flows up through a bed of near mono-sized particles, it fluidizes when the pressure drop across the bed is equal to the weight of the bed. Normally, the weight of the bed is determined by gravity. However, if the bed is contained by a cylindrical air distributor plate that is rotating rapidly about its axis, then the effective weight of the bed can be increased dramatically. The airflow passing through the bed can be increased proportionally to the g level produced by the rotation and it follows that the process has been intensified. In exploratory tests with a spinning fluidized bed the authors have achieved combustion intensities with coal combustion as high as 100 MW/m{sup 3}. A problem with burning coal is that it was difficult to remove the heat and rotating water seals had to be used to transfer cooling water into the bed. In the case of sewage and other sludges, this problem does not exist since the flue gases can remove the small amount of heat released. The rotating fluidized bed sludge incinerator is a novel device, which is very compact. It is able to solve the turndown problem encountered with conventional fluidized beds by simply changing the rotation speed. Bearing in mind that a centrifugal sludge

  17. An innovative vibration fluidized bed ash cooler

    SciTech Connect

    Duan, Y.; Zhang, M.; Liu, A.; Yao, Z.; Tang, H.; Liu, Q.

    1999-07-01

    With the ever-increasing versatility, scaling up and commercialization of coal-fired fluidized bed boiler technologies, it has become more and more important to improve the technique of draining bed ash from bubbling or circulating fluidized bed boilers. Choosing an ash cooler is a good way but highly stable and reliable system is hard to find for a massive ash flow rate having a broad particle size distributions. An innovative technique known as Vibration Fluidized Bed Ash Cooler (VFBAC) is proposed in this paper. It can drain bottom ash at a high temperature from FB or CFB boilers continuously and controllably. In this device, air used for cooling can be used as combustion-aided air or coal spreading air. The hot ash is cooled by the air to a temperature which it can be transported easily and safely by conventional technology. Meanwhile, an industrial apparatus utilizing the new technology was manufactured and used in a 35 t/h bubbling FB boiler. For the purpose of detecting residence time distribution of wide-sieved bed materials in this ash cooler systematically, advantage was taken of a new approach for physical quality discrimination. Investigations into the hydrodynamic characteristics of the gas-solid two-phase flows and theoretical analyses on hot operational performance were carried out. The results show that heat recovery efficiency of the ash cooler reaches 85% greater when operating at a ratio of air to ash of 1.5{approximately}2.5 Nm{sup 3}/kg.

  18. PRISMA Formatio n Flying Project in System Test Phase

    NASA Astrophysics Data System (ADS)

    Persson, S.

    2008-08-01

    The PRISMA project for in-flight demonstration of autonomous formation flying and rendezvous is well into the flight units integration and integrated systems testing stage. The project comprises two satellites which constitute an in-orbit test bed for Guidance, Navigation and Control (GNC) algorithms and sensors for advanced formation flying and rendezvous. Several experiments involving GNC algorithms, sensors (GPS, RF and vision based) and thrusters, will be performed during a 10 month mission with launch planned for the first half of 2009. The project now enters the system level testing phase. This paper gives a brief overview of the project and highlights several steps in the system level verification process.

  19. Collaborative Strategy on Bed Bugs

    EPA Pesticide Factsheets

    The Collaborative Strategy on Bed Bugs was developed by the Federal Bed Bug Workgroup to clarify the federal role in bed bug control and highlight ways that government, community, academia and private industry can work together on bed bug issues.

  20. Photolysis of polycyclic aromatic hydrocarbons adsorbed on fly ash

    SciTech Connect

    Behymer, T.D.

    1987-01-01

    Polycyclic aromatic hydrocarbons (PAH) are formed by the combustion of almost any fuel under oxygen-deficient conditions. Previous laboratory studies have found that many PAH degrade with lifetimes as short as a few hours; however, studies of marine and lacustrine sediments, the ultimate sinks of PAH, have shown relative abundances of PAH which are similar to those in combustion sources; this suggests that PAH are stable in the atmosphere. Eighteen PAH adsorbed on carbon black and fifteen coal fly ashes of varying physical and chemical composition were photolyzed in order to study their atmospheric fate. Photolytic half-lives for these particle-bound PAH were found to be highly dependent on the substrate onto which they were adsorbed. On low-carbon fly ash, PAH showed a wide range of half-lives, indicating a relationship between PAH structure and photochemical reactivity. However, PAH on carbon black and fly ashes with a high-carbon content, show similar half-lives for most PAH including reactive PAH such as anthracene and benzo(a)pyrene. This indicates a photolytic process that is independent of structure and dependent on the physical and chemical nature of the fly ash. Surprisingly, no other parameter accounts for observed PAH reactivity. Substrate characteristics such as surface area, porosity, particle size, surface pH, and iron content have all been suggested to influence the rate of PAH degradation. However, these parameters, measured for substrates studied in this thesis, do not correlate with PAH reactivity. Because carbon black and high-carbon fly ashes stabilize reactive PAH, it is these substrates which would facilitate the transport of PAH from combustion sources through the atmosphere to ultimate sinks.