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1

Model-based scale-up and performance of the Biogas Tower Reactor for anaerobic waste-water treatment  

Microsoft Academic Search

The Biogas Tower Reactor (BTR), a new type of reactor for anaerobic waste-water treatment, is presented. The characteristic features of the BTR are the tower shape, its modular structure and the internal installations. Gas loading, mixing and sludge distribution can be controlled. A settler is installed on top of the reactor. Performance data of a pilot-scale BTR are presented for

G. Reinhold; H. Märkl

1997-01-01

2

Anaerobic baffled reactor treatment of biodiesel-processing wastewater with high strength of methanol and glycerol: reactor performance and biogas production  

Microsoft Academic Search

Biodiesel-processing factories employing the alkali-catalyzed transesterification process generate a large amount of wastewater\\u000a containing high amount of methanol, glycerol, and oil. As such, wastewater has high potential to produce biogas using anaerobic\\u000a treatment. The aim of this research was to investigate the performance of an anaerobic baffled reactor for organic removal\\u000a and biogas production from biodiesel wastewater. The effect of

Darin Phukingngam; Orathai Chavalparit; Dararat Somchai; Maneerat Ongwandee

2011-01-01

3

Performance of anaerobic hybrid reactors for the treatment of complex phenolic wastewaters with biogas recirculation.  

PubMed

This study investigates the application of a novel anaerobic hybrid reactor (AHR) configuration, incorporating support media for biomass immobilisation and biogas recirculation for improved mixing towards the anaerobic treatment of complex phenolic wastewater. Synthetic coal wastewater with an average phenolics and COD concentration of 752 and 2240 mg L(-1) was used as substrate. Biogas recirculation was employed at four different rates of 11.25, 16.87, 25.30 and 37.95 L d(-1) for 100 days. Phenolics and COD removal improved with increase in biogas recirculation. After 120 days of continuous operation, the results revealed that a high amount (14.0 g VSS) of biomass was able to attach itself to the support medium. The investigated AHR configuration achieved phenolics and COD removal efficiencies of 95% and 92% respectively at a hydraulic retention time (HRT) of 0.33 d. The corresponding average methane production obtained in this study was 0.02 mol methane g(-1) COD. PMID:23232220

Ramakrishnan, Anushuya; Surampalli, Rao Y

2012-11-16

4

Performance and microbial community analysis of the anaerobic reactor with coke oven gas biomethanation and in situ biogas upgrading.  

PubMed

A new method for simultaneous coke oven gas (COG) biomethanation and in situ biogas upgrading in anaerobic reactor was developed in this study. The simulated coke oven gas (SCOG) (92% H2 and 8% CO) was injected directly into the anaerobic reactor treating sewage sludge through hollow fiber membrane (HFM). With pH control at 8.0, the added H2 and CO were fully consumed and no negative effects on the anaerobic degradation of sewage sludge were observed. The maximum CH4 content in the biogas was 99%. The addition of SCOG resulted in enrichment and dominance of homoacetogenetic genus Treponema and hydrogenotrophic genus Methanoculleus in the liquid, which indicated that H2 were converted to methane by both direct (hydrogenotrophic methanogenesis) and indirect (homoacetogenesis+aceticlastic methanogenesis) pathways in the liquid. However, the aceticlasitic genus Methanosaeta was dominant for archaea in the biofilm on the HFM, which indicated indirect (homoacetogenesis+aceticlastic methanogenesis) H2 conversion pathway on the biofilm. PMID:23941705

Wang, Wen; Xie, Li; Luo, Gang; Zhou, Qi; Angelidaki, Irini

2013-07-22

5

[Effect of the ratio of height to diameter on the performance of the simultaneous reactor for nitrogen removal from swine wastewater and sulfide removal from biogas].  

PubMed

The effect of the ratio of height to diameter (H/D) on the process of simultaneous nitrogen removal from swine wastewater and hydrogen sulfide removal from biogas was investigated, using the bubble column reactors with packing material. The performance of the reactor with H/D of 8 : 1, 3 :1 and 2 : 1 was compared. Under temperature of 30-32 degrees C, gas retention time of 6.70 min, hydraulic retention time of 3.35 d, hydrogen sulfide concentration of 1 414-1 838 mg x m(-3) in biogas, and NO(x)(-) -N concentration of 114-243 mg x L(-1) in influent. The reactor with H/D of 2 : 1 achieved a stable and good treatment result, with the average removal rates of 96.7% for hydrogen sulfide, and 88.7% for N(x)(-) -N. While the reactors with H/D of 3 : 1 and 8 : 1 obtained unstable and inferior results, with the average removal rates of 68.0%, 80.4% for hydrogen sulfide respectively, and 89.7%, 90.2% for NO(x)(-) -N respectively. The reason could be attributed to the following facts. The reactor with H/D of 2:1 has a slower optimum gas velocity (3.12 x 10(-2) m x s(-1))- than the reactor with H/D of 3 : 1 and 8 : 1 (3.62 x 10(-2) m x s(-1) and 6.64 x 10(-2) m x s(-1) respectively), and has a higher gas-liquid mass transfer coefficient (1.79 x 10(-5) s(-1)) than the other two reactors (1.64 x 10(-5) s(-1) and 1.55 x 10(-5) s(-1) respectively). Results of the performance and the hydrodynamics parameters of the reactors all indicated that the reactor with H/D of 2 : 1 was more suitable for the process of simultaneous nitrogen and hydrogen sulfide removal. PMID:21072949

Sun, Zhu; Wu, Jun; Pu, Xiao-Dong; Deng, Liang-Wei

2010-09-01

6

Performance of biogas plants of different designs  

SciTech Connect

The performance of different designs of biogas digesters were evaluated at four Khadi and Village Industries Commission (KVIC) regional centres in: Vijapadi in Gujarat, Nasik in Maharashtra, Srinagar in Jammu and Kashmir, and Allahabad in Uttar Pradesh, India. The information provided in the evaluation includes the average daily gas production per unit of digester volume for each month, the total gas produced per unit of digester volume over an 18-month period, the costs of the KVIC-designed biogas digesters of different volume and the expenditures incurred in installing biogas digesters of different design.

Not Available

1981-08-01

7

Start-up and Performance of a Novel Reactor—Jet Biogas Inter-loop Anaerobic Fluidized Bed * * Supported by the National Natural Science Foundation of China (No.50278036), the Natural Science Foundation of Guangdong Province (No.04105951) and the National High Technology Research and Development Program of China (No.2006AA06Z378)  

Microsoft Academic Search

A novel anaerobic reactor, jet biogas inter-loop anaerobic fluidized bed (JBILAFB), was designed and constructed. The start-up and performance of the reactor was investigated in the process of artificial glucose wastewater treatment. With the wastewater recycle ratio of 2.5 : 1, the recycled wastewater with biogas could mix sludge and wastewater in the JBILAFB reactor completely. The start-up of the

Zhiyi DENG; Chaohai WEI; Xiufeng ZHOU

2008-01-01

8

Bioaugmentation of Syntrophic Acetate-Oxidizing Culture in Biogas Reactors Exposed to Increasing Levels of Ammonia  

PubMed Central

The importance of syntrophic acetate oxidation for process stability in methanogenic systems operating at high ammonia concentrations has previously been emphasized. In this study we investigated bioaugmentation of syntrophic acetate-oxidizing (SAO) cultures as a possible method for decreasing the adaptation period of biogas reactors operating at gradually increased ammonia concentrations (1.5 to 11 g NH4+-N/liter). Whole stillage and cattle manure were codigested semicontinuously for about 460 days in four mesophilic anaerobic laboratory-scale reactors, and a fixed volume of SAO culture was added daily to two of the reactors. Reactor performance was evaluated in terms of biogas productivity, methane content, pH, alkalinity, and volatile fatty acid (VFA) content. The decomposition pathway of acetate was analyzed by isotopic tracer experiments, and population dynamics were monitored by quantitative PCR analyses. A shift in dominance from aceticlastic methanogenesis to SAO occurred simultaneously in all reactors, indicating no influence by bioaugmentation on the prevailing pathway. Higher abundances of Clostridium ultunense and Tepidanaerobacter acetatoxydans were associated with bioaugmentation, but no influence on Syntrophaceticus schinkii or the methanogenic population was distinguished. Overloading or accumulation of VFA did not cause notable dynamic effects on the population. Instead, the ammonia concentration had a substantial impact on the abundance level of the microorganisms surveyed. The addition of SAO culture did not affect process performance or stability against ammonia inhibition, and all four reactors deteriorated at high ammonia concentrations. Consequently, these findings further demonstrate the strong influence of ammonia on the methane-producing consortia and on the representative methanization pathway in mesophilic biogas reactors.

Westerholm, Maria; Leven, Lotta

2012-01-01

9

Control of an anaerobic reactor towards maximum biogas production  

Microsoft Academic Search

A new control strategy is introduced for operating anaerobic digestion processes efficiently at high load. The control system includes a cascade controller embedded into a rule-based supervisory system based on extremum-seeking control. The control system measures pH and biogas production rate and varies the organic load by manipulating the influent flow. Good control performances were achieved during the start-up and

J. Liu; G. Olsson; B. Mattiasson

10

Antifoaming effect of chemical compounds in manure biogas reactors.  

PubMed

A precise and efficient antifoaming control strategy in bioprocesses is a challenging task as foaming is a very complex phenomenon. Nevertheless, foam control is necessary, as foam is a major operational problem in biogas reactors. In the present study, the effect of 14 chemical compounds on foam reduction was evaluated at concentration of 0.05%, 0.1% and 0.5% v/vsample, in raw and digested manure. Moreover, two antifoam injection methods were compared for foam reduction efficiency. Natural oils (rapeseed and sunflower oil), fatty acids (oleic, octanoic and derivative of natural fatty acids), siloxanes (polydimethylsiloxane) and ester (tributylphosphate) were found to be the most efficient compounds to suppress foam. The efficiency of antifoamers was dependant on their physicochemical properties and greatly correlated to their chemical characteristics for dissolving foam. The antifoamers were more efficient in reducing foam when added directly into the liquid phase rather than added in the headspace of the reactor. PMID:23972674

Kougias, P G; Tsapekos, P; Boe, K; Angelidaki, I

2013-08-09

11

Integrated biogas upgrading and hydrogen utilization in an anaerobic reactor containing enriched hydrogenotrophic methanogenic culture.  

PubMed

Biogas produced by anaerobic digestion, is mainly used in a gas motor for heat and electricity production. However, after removal of CO(2) , biogas can be upgraded to natural gas quality, giving more utilization possibilities, such as utilization as autogas, or distant utilization by using the existing natural gas grid. The current study presents a new biological method for biogas upgrading in a separate biogas reactor, containing enriched hydrogenotrophic methanogens and fed with biogas and hydrogen. Both mesophilic- and thermophilic anaerobic cultures were enriched to convert CO(2) to CH(4) by addition of H(2) . Enrichment at thermophilic temperature (55°C) resulted in CO(2) and H(2) bioconversion rate of 320?mL CH(4) /(gVSS?h), which was more than 60% higher than that under mesophilic temperature (37°C). Different dominant species were found at mesophilic- and thermophilic-enriched cultures, as revealed by PCR-DGGE. Nonetheless, they all belonged to the order Methanobacteriales, which can mediate hydrogenotrophic methanogenesis. Biogas upgrading was then tested in a thermophilic anaerobic reactor under various operation conditions. By continuous addition of hydrogen in the biogas reactor, high degree of biogas upgrading was achieved. The produced biogas had a CH(4) content, around 95% at steady-state, at gas (mixture of biogas and hydrogen) injection rate of 6?L/(L?day). The increase of gas injection rate to 12?L/(L?day) resulted in the decrease of CH(4) content to around 90%. Further study showed that by decreasing the gas-liquid mass transfer by increasing the stirring speed of the mixture the CH(4) content was increased to around 95%. Finally, the CH(4) content around 90% was achieved in this study with the gas injection rate as high as 24?L/(L?day). PMID:22615033

Luo, Gang; Angelidaki, Irini

2012-05-28

12

Modelling the hydrodynamics and the liquid-mixing behaviour of a biogas tower reactor  

Microsoft Academic Search

A new concept of a biogas reactor for anaerobic waste water treatment is presented. The characteristic features of this type of reactor are the tower shape, its modular structure and the internal installations. Gas-collecting devices are installed at different levels along the height of the reactor to withdraw the gas produced and to avoid gas accumulation in the upper zones

Georg Reinhold; Stefan Merrath; Friedrich Lennemann; Herbert Märkl

1996-01-01

13

Mathematical modeling of process liquid flow and acetoclastic methanogenesis under mesophilic conditions in a two-phase biogas reactor.  

PubMed

Acetoclastic methanogenesis in the second stage of a two-phase biogas reactor is investigated. A mathematical model coupling chemical reactions with transport of process liquid and with the variation of population of the microorganisms living on the plastic tower packing of the reactor is proposed. The evolution of the liquid is described by an advection-diffusion-reaction equation, while a monod-type kinetic is used for the reactions. Moreover, a new inhibition factor MO(max) is introduced, which hinders the growth of microorganisms when the plastic tower packing is overpopulated. After estimating the reaction parameters, the acetate outflow measured experimentally is in good agreement with that predicted by simulations. For coupling liquid transport with reaction processes, a spatial discretization of the reactor is performed. This yields essential information about the distribution of acetate and the production of methane in the reactor. This information allows for defining a measure of the effectiveness of the reactor. PMID:22206918

Muha, Ivo; Grillo, Alfio; Heisig, Michael; Schönberg, Mandy; Linke, Bernd; Wittum, Gabriel

2011-12-01

14

Characteristics and biogas production potential of municipal solid wastes pretreated with a rotary drum reactor  

Microsoft Academic Search

This study was conducted to determine the characteristics and biogas production potential of organic materials separated from municipal solid wastes using a rotary drum reactor (RDR) process. Four different types of wastes were first pretreated with a commercial RDR system at different retention times (1, 2 and 3 d) and the organic fractions were tested with batch anaerobic digesters with

Baoning Zhu; Petros Gikas; Ruihong Zhang; James Lord; Bryan Jenkins; Xiujin Li

2009-01-01

15

Influence of Environmental Conditions on Methanogenic Compositions in Anaerobic Biogas Reactors  

Microsoft Academic Search

The influence of environmental parameters on the diversity of methanogenic communities in 15 full-scale biogas plants operating under different conditions with either manure or sludge as feedstock was studied. Fluorescence in situ hybridization was used to identify dominant methanogenic members of the Archaea in the reactor samples; enriched and pure cultures were used to support the in situ identification. Dominance

Dimitar Karakashev; Damien J. Batstone; Irini Angelidaki

2005-01-01

16

Effect of reactor configuration on biogas production from wheat straw hydrolysate  

Microsoft Academic Search

The potential of wheat straw hydrolysate for biogas production was investigated in continuous stirred tank reactor (CSTR) and up-flow anaerobic sludge bed (UASB) reactors. The hydrolysate originated as a side stream from a pilot plant pretreating wheat straw hydrothermally (195°C for 10–12min) for producing 2nd generation bioethanol [Kaparaju, P., Serrano, M., Thomsen, A.B., Kongjan, P., Angelidaki, I., 2009. Bioethanol, biohydrogen

Prasad Kaparaju; María Serrano; Irini Angelidaki

2009-01-01

17

Simultaneous hydrogen utilization and in situ biogas upgrading in an anaerobic reactor.  

PubMed

The possibility of converting hydrogen to methane and simultaneous upgrading of biogas was investigated in both batch tests and fully mixed biogas reactor, simultaneously fed with manure and hydrogen. Batch experiments showed that hydrogen could be converted to methane by hydrogenotrophic methanogenesis with conversion of more than 90% of the consumed hydrogen to methane. The hydrogen consumption rates were affected by both P(H?) (hydrogen partial pressure) and mixing intensity. Inhibition of propionate and butyrate degradation by hydrogen (1?atm) was only observed under high mixing intensity (shaking speed 300?rpm). Continuous addition of hydrogen (flow rate of 28.6?mL/(L/h)) to an anaerobic reactor fed with manure, showed that more than 80% of the hydrogen was utilized. The propionate and butyrate level in the reactor was not significantly affected by the hydrogen addition. The methane production rate of the reactor with H? addition was 22% higher, compared to the control reactor only fed with manure. The CO? content in the produced biogas was only 15%, while it was 38% in the control reactor. However, the addition of hydrogen resulted in increase of pH (from 8.0 to 8.3) due to the consumption of bicarbonate, which subsequently caused slight inhibition of methanogenesis. PMID:22068262

Luo, Gang; Johansson, Sara; Boe, Kanokwan; Xie, Li; Zhou, Qi; Angelidaki, Irini

2011-11-21

18

Effect of organic loading rate and feedstock composition on foaming in manure-based biogas reactors.  

PubMed

Foaming is one of the major problems that occasionally occur in biogas plants, affecting negatively the overall digestion process. In the present study, the effect of organic loading rate (OLR) and feedstock composition on foaming was elucidated in continuous reactor experiments. By stepwise increasing the OLR and the concentration of proteins or lipids in the substrate, foaming in biogas reactors was investigated. No foam formation was observed at the OLR of 3.5g volatile solids/(L-reactor·day). Organic loading was the main factor affecting foam formation in manure digester, while the organic composition, such as content of proteins or lipids were factors that in combination with the organic loading were triggering foaming. More specifically, gelatine could initiate foam formation at a lower OLR than sodium oleate. Moreover, the volume of foam produced by gelatine was relatively stable and was not increased when further increasing either OLR or gelatine concentration in the feed. PMID:23850819

Kougias, P G; Boe, K; Angelidaki, I

2013-06-15

19

Temperature increases from 55 to 75 °C in a two-phase biogas reactor result in fundamental alterations within the bacterial and archaeal community structure.  

PubMed

Agricultural biogas plants were operated in most cases below their optimal performance. An increase in the fermentation temperature and a spatial separation of hydrolysis/acetogenesis and methanogenesis are known strategies in improving and stabilizing biogas production. In this study, the dynamic variability of the bacterial and archaeal community was monitored within a two-phase leach bed biogas reactor supplied with rye silage and straw during a stepwise temperature increase from 55 to 75 °C within the leach bed reactor (LBR), using TRFLP analyses. To identify the terminal restriction fragments that were obtained, bacterial and archaeal 16S rRNA gene libraries were constructed. Above 65 °C, the bacterial community structure changed from being Clostridiales-dominated toward being dominated by members of the Bacteroidales, Clostridiales, and Thermotogales orders. Simultaneously, several changes occurred, including a decrease in the total cell count, degradation rate, and biogas yield along with alterations in the intermediate production. A bioaugmentation with compost at 70 °C led to slight improvements in the reactor performance; these did not persist at 75 °C. However, the archaeal community within the downstream anaerobic filter reactor (AF), operated constantly at 55 °C, altered by the temperature increase in the LBR. At an LBR temperature of 55 °C, members of the Methanobacteriales order were prevalent in the AF, whereas at higher LBR temperatures Methanosarcinales prevailed. Altogether, the best performance of this two-phase reactor was achieved at an LBR temperature of below 65 °C, which indicates that this temperature range has a favorable effect on the microbial community responsible for the production of biogas. PMID:22899497

Rademacher, Antje; Nolte, Christine; Schönberg, Mandy; Klocke, Michael

2012-08-17

20

Unexpected Stability of Bacteroidetes and Firmicutes Communities in Laboratory Biogas Reactors Fed with Different Defined Substrates  

PubMed Central

In the present study, bacterial communities in 200-liter biogas reactors containing liquid manure consecutively fed with casein, starch, and cream were investigated over a period of up to 33 days. A 16S rRNA gene clone library identified Bacteroidetes and Firmicutes as the most abundant bacterial groups in the starting material, at 58.9% and 30.1% of sequences, respectively. The community development of both groups was monitored by real-time PCR and single-strand conformation polymorphism (SSCP) analysis. The Firmicutes and Bacteroidetes communities were unexpectedly stable and hardly influenced by batch-feeding events. The continuous feeding of starch led to community shifts that nevertheless contributed to a stable reactor performance. A longer starving period and a change in the pH value resulted in further community shifts within the Bacteroidetes but did not influence the Firmicutes. Predominant DNA bands from SSCP gels were cloned and sequenced. Sequences related to Peptococcaceae, Cytophagales, and Petrimonas sulfuriphila were found in all samples from all experiments. Real-time PCR demonstrated the abundance of members of the phylum Bacteroidetes and also reflected changes in gene copy numbers in conjunction with a changing pH value and acetate accumulation.

Ratering, S.; Kramer, I.; Schmidt, M.; Zerr, W.; Schnell, S.

2012-01-01

21

Effect of hydrogen addition on the performance of a biogas fuelled spark ignition engine  

Microsoft Academic Search

Hydrogen was added in small amounts (5%, 10% and 15% on the energy basis) to biogas and tested in a spark ignition engine at constant speed at different equivalence ratios to study the effects on performance, emissions and combustion. Hydrogen significantly enhances the combustion rate and extends the lean limit of combustion of biogas. There is an improvement in brake

E. Porpatham; A. Ramesh; B. Nagalingam

2007-01-01

22

Inactivation of virus during anaerobic digestion of manure in laboratory scale biogas reactors  

Microsoft Academic Search

Reduction of porcine parvovirus, bovine enterovirus and faecal enterococci were measured in biogas reactors continuously run\\u000a on manure and manure supplemented with household waste at 35°C and 55°C and in batch test run at 70°C. The aim of the experiments\\u000a was to study the sanitation effect of anaerobic digestion and to evaluate the use of faecal enterococci as an indicator

Bente Lund; Vibeke Frøkjær Jensen; Per Have; Birgitte Ahring

1996-01-01

23

Process performance of biogas digesters incorporating pre-separated manure  

Microsoft Academic Search

The yield from anaerobic digestion of liquid manure is often too low to make biogas production economically viable. This study examined the potential for partly substituting the liquid manure with solids from solid–liquid separation. The proportion of manure solids was gradually increased to 60%, which resulted in a higher gas production per digester volume than could be achieved by liquid

H. B. Møller; A. M. Nielsen; R. Nakakubo; H. J. Olsen

2007-01-01

24

Catalytic steam reforming of model biogas  

Microsoft Academic Search

Catalytic steam reforming of a model biogas (CH4\\/CO2=60\\/40) is investigated to produce H2-rich synthesis gas. Gas engines benefit from synthesis gas fuel in terms of higher efficiency and lower NOx production when compared to raw biogas or CH4. The process is realized in a fixed bed reactor with a Ni-based catalyst on CaO\\/Al2O3 support. To optimize the performance, the reactor

Philipp Kolbitsch; Christoph Pfeifer; Hermann Hofbauer

2008-01-01

25

Microbial community analysis of a biogas-producing completely stirred tank reactor fed continuously with fodder beet silage as mono-substrate  

Microsoft Academic Search

The bioconversion of renewable raw material to biogas by anaerobic microbial fermentation processes in completely stirred tank reactors (CSTR) is a valuable alternative resource of energy especially for rural areas. However, knowledge about the microorganisms involved in the degradation of plant biomass is still poor. In this study, a first analysis of the biogas-forming process within a CSTR fed continuously

Michael Klocke; Pia Mähnert; Kerstin Mundt; Khadidja Souidi; Bernd Linke

2007-01-01

26

Influence of Environmental Conditions on Methanogenic Compositions in Anaerobic Biogas Reactors  

PubMed Central

The influence of environmental parameters on the diversity of methanogenic communities in 15 full-scale biogas plants operating under different conditions with either manure or sludge as feedstock was studied. Fluorescence in situ hybridization was used to identify dominant methanogenic members of the Archaea in the reactor samples; enriched and pure cultures were used to support the in situ identification. Dominance could be identified by a positive response by more than 90% of the total members of the Archaea to a specific group- or order-level probe. There was a clear dichotomy between the manure digesters and the sludge digesters. The manure digesters contained high levels of ammonia and of volatile fatty acids (VFA) and were dominated by members of the Methanosarcinaceae, while the sludge digesters contained low levels of ammonia and of VFA and were dominated by members of the Methanosaetaceae. The methanogenic diversity was greater in reactors operating under mesophilic temperatures. The impact of the original inoculum used for the reactor start-up was also investigated by assessment of the present population in the reactor. The inoculum population appeared to have no influence on the eventual population.

Karakashev, Dimitar; Batstone, Damien J.; Angelidaki, Irini

2005-01-01

27

Performance of a flameless combustion furnace using biogas and natural gas.  

PubMed

Flameless combustion technology has proved to be flexible regarding the utilization of conventional fuels. This flexibility is associated with the main characteristic of the combustion regime, which is the mixing of the reactants above the autoignition temperature of the fuel. Flameless combustion advantages when using conventional fuels are a proven fact. However, it is necessary to assess thermal equipments performance when utilizing bio-fuels, which usually are obtained from biomass gasification and the excreta of animals in bio-digesters. The effect of using biogas on the performance of an experimental furnace equipped with a self-regenerative Flameless burner is reported in this paper. All the results were compared to the performance of the system fueled with natural gas. Results showed that temperature field and uniformity are similar for both fuels; although biogas temperatures were slightly lower due to the larger amount of inert gases (CO(2)) in its composition that cool down the reactions. Species patterns and pollutant emissions showed similar trends and values for both fuels, and the energy balance for biogas showed a minor reduction of the efficiency of the furnace; this confirms that Flameless combustion is highly flexible to burn conventional and diluted fuels. Important modifications on the burner were not necessary to run the system using biogas. Additionally, in order to highlight the advantages of the Flameless combustion regime, some comparisons of the burner performance working in Flameless mode and working in conventional mode are presented. PMID:19944602

Colorado, A F; Herrera, B A; Amell, A A

2009-11-26

28

Guidebook on biogas development  

SciTech Connect

This guidebook covers the practical aspects of small-scale biogas development suitable for use in rural areas in developing countries, especially those of the ESCAP region. It is intended that all aspects of biogas are covered so that someone with no knowledge of the subject can, with confidence, design, build, operate and maintain a biogas plant. Information on biogas technology in China is also included. Chapters cover: the biogas process; factors effecting gas-plant design and operation; the classification and design principles of plants; design, size and site selection; the construction of digesters; gas holders and pipes; household gas appliances and their use; starting and operating a biogas digester; servicing and safety; improving gas-plant performance; commercial uses of biogas; the effluent and its uses, biogas-plant development programmes; community plants; and economics. In the annexes, designs for biogas plants of the fixed-dome, bag and floating gas-holder type are presented. 9 references.

Not Available

1980-01-01

29

Effects of mixing system and pilot fuel quality on diesel-biogas dual fuel engine performance.  

PubMed

This paper describes results obtained from CI engine performance running on dual fuel mode at fixed engine speed and four loads, varying the mixing system and pilot fuel quality, associated with fuel composition and cetane number. The experiments were carried out on a power generation diesel engine at 1500 m above sea level, with simulated biogas (60% CH(4)-40% CO(2)) as primary fuel, and diesel and palm oil biodiesel as pilot fuels. Dual fuel engine performance using a naturally aspirated mixing system and diesel as pilot fuel was compared with engine performance attained with a supercharged mixing system and biodiesel as pilot fuel. For all loads evaluated, was possible to achieve full diesel substitution using biogas and biodiesel as power sources. Using the supercharged mixing system combined with biodiesel as pilot fuel, thermal efficiency and substitution of pilot fuel were increased, whereas methane and carbon monoxide emissions were reduced. PMID:19683439

Bedoya, Iván Darío; Arrieta, Andrés Amell; Cadavid, Francisco Javier

2009-08-14

30

Treatment of food processing wastewater in a full-scale jet biogas internal loop anaerobic fluidized bed reactor.  

PubMed

A full-scale jet biogas internal loop anaerobic fluidized bed (JBILAFB) reactor, which requires low energy input and allows enhanced mass transfer, was constructed for the treatment of food processing wastewater. This reactor has an active volume of 798 m(3) and can treat 33.3 m(3) wastewater per hour. After pre-treating the raw wastewater by settling, oil separating and coagulation-air floating processes, the reactor was operated with a relatively shorter start-up time (55 days). Samples for the influent and effluent of the JBILAFB reactor were taken and analyzed daily for the whole process including both the start-up and stable running periods. When the volumetric COD loading fluctuated in the range of 1.6-5.6 kg COD m(-3) day(-1), the COD removal efficiency, the volatile fatty acid(VFA)/alkalinity ratio, the maximum biogas production and the content of CH(4) in total biogas of the reactor were found to be 80.1 ± 5%, 0.2-0.5, 348.5 m(3 )day(-1) and 94.5 ± 2.5%, respectively. Furthermore, the scanning electron microscope (SEM) results showed that anaerobic granular sludge and microorganism particles with biofilm coexisted in the reactor, and that the bacteria mainly in bacilli and cocci were observed as predominant species. All the data demonstrated that the enhanced mass transfer for gas, liquid and solid phases was achieved, and that the formation of microorganism granules and the removal of inhibitors increased the stability of the system. PMID:20717838

Wei, Chaohai; Zhang, Tao; Feng, Chunhua; Wu, Haizhen; Deng, Zhiyi; Wu, Chaofei; Lu, Bin

2010-08-19

31

A fuzzy-logic-based model to predict biogas and methane production rates in a pilot-scale mesophilic UASB reactor treating molasses wastewater.  

PubMed

A MIMO (multiple inputs and multiple outputs) fuzzy-logic-based model was developed to predict biogas and methane production rates in a pilot-scale 90-L mesophilic up-flow anaerobic sludge blanket (UASB) reactor treating molasses wastewater. Five input variables such as volumetric organic loading rate (OLR), volumetric total chemical oxygen demand (TCOD) removal rate (R(V)), influent alkalinity, influent pH and effluent pH were fuzzified by the use of an artificial intelligence-based approach. Trapezoidal membership functions with eight levels were conducted for the fuzzy subsets, and a Mamdani-type fuzzy inference system was used to implement a total of 134 rules in the IF-THEN format. The product (prod) and the centre of gravity (COG, centroid) methods were employed as the inference operator and defuzzification methods, respectively. Fuzzy-logic predicted results were compared with the outputs of two exponential non-linear regression models derived in this study. The UASB reactor showed a remarkable performance on the treatment of molasses wastewater, with an average TCOD removal efficiency of 93 (+/-3)% and an average volumetric TCOD removal rate of 6.87 (+/-3.93) kg TCOD(removed)/m(3)-day, respectively. Findings of this study clearly indicated that, compared to non-linear regression models, the proposed MIMO fuzzy-logic-based model produced smaller deviations and exhibited a superior predictive performance on forecasting of both biogas and methane production rates with satisfactory determination coefficients over 0.98. PMID:20609515

Turkdogan-Aydinol, F Ilter; Yetilmezsoy, Kaan

2010-06-18

32

Anaerobic bioconversion of carbon dioxide to biogas in an upflow anaerobic sludge blanket reactor.  

PubMed

The increasing concentration of carbon dioxide (CO2)--the most dominant component of greenhouse gases--in the atmosphere has been of growing concern for many years. Many methods focus on CO2 capture and storage and there is always the risk of CO2 release to the environment. In this study, a new method to convert CO2 to biogas with a high content of methane (CH4) in an anaerobic system with a lab-scale upflow anaerobic sludge blanket reactor at 35 degrees C was developed. In a series of experiments, the reactor was run with and without CO2-saturated solutions including volatile fatty acids (VFAs) as sources of hydrogen. The concentration of dissolved CO2 in the influent solutions was 2.2-6.1 g/L, with corresponding chemical oxygen demand (COD) values of 2.6-8.4 g/L for the solutions. Overall CO2 removal values of 2.7-20 g/day (49-88% conversion) were obtained for the organic loading rates (OLR) and CO2 loading rates of 8-36 gCOD/L day and 6-26 gCO2/L x day, respectively with CH4 purity of above 70%. Also, VFA and COD removal were in the range of 79-95% and 75-90%, respectively. Methanogenic activities of the cultures with the concentrations measured as volatile suspended solids (VSSs) were 0.12-0.40 L CH4/gVSS x d with the highest value for the system containing acetic acid. This anaerobic method can be applied to reduce CO2 emitted to the atmosphere from a wide variety of industrial point sources with a value-added product, CH4. PMID:18236799

Alimahmoodi, Mahmood; Mulligan, Catherine N

2008-01-01

33

Assessment of energy performance in the life-cycle of biogas production  

Microsoft Academic Search

Energy balances are analysed from a life-cycle perspective for biogas systems based on 8 different raw materials. The analysis is based on published data and relates to Swedish conditions. The results show that the energy input into biogas systems (i.e. large-scale biogas plants) overall corresponds to 20–40% (on average approximately 30%) of the energy content in the biogas produced. The

Maria Berglund; Pål Börjesson

2006-01-01

34

Continuous production of biogas from dairy manure using an innovative no-mix reactor  

Microsoft Academic Search

A 25 L no-mix anaerobic digester was designed and fabricated. The digester was designed to act as liquid-solid separator.\\u000a The sludges obtained from the bottom of the digester had high nitrogen and ash concentrations while the effluent had no offensive\\u000a odor. The performance of the no-mix digester was compared to that of a continuous stirred tank reactor at two temperatures

A. E. Ghaly; R. M. Ben-Hassan

1989-01-01

35

Do two-phase biogas plants separate anaerobic digestion phases? - a mathematical model for the distribution of anaerobic digestion phases among reactor stages.  

PubMed

In this article a mathematical model is introduced, which estimates the distribution of the four anaerobic digestion phases (hydrolysis, acidogenesis, acetogenesis and methanogenesis) that occur among the leach bed reactor and the anaerobic filter of a biogas plant. It is shown that only the hydrolysis takes place in the first stage (leach bed reactor), while all other anaerobic digestion phases take place in both reactor stages. It turns out that, besides the usually measured raw materials of the acetogenesis and the methanogenesis phases (organic acids), it is also necessary to analyze the process liquid for raw materials of the acidogenesis phase, i.e., sugars, fatty acids, amino acids, etc. The introduced model can be used to monitor the inhibition of the anaerobic digestion phases in reactor stages and can, thus, help to improve the control system of biogas plants. PMID:23290872

Muha, Ivo; Zielonka, Simon; Lemmer, Andreas; Schönberg, Mandy; Linke, Bernd; Grillo, Alfio; Wittum, Gabriel

2012-12-14

36

Anaerobic Bioconversion of Carbon Dioxide to Biogas in an Upflow Anaerobic Sludge Blanket Reactor  

Microsoft Academic Search

The increasing concentration of carbon dioxide (CO2)—the most dominant component of greenhouse gases—in the atmosphere has been of growing concern for many years. Many methods focus on CO2 capture and storage and there is always the risk of CO2 release to the environment. In this study, a new method to convert CO2 to biogas with a high content of methane

Mahmood Alimahmoodi; Catherine N. Mulligan; Kevin Black; R. Graze; John Koupal; Fred Minassian; Hannah Murray; Mani Natarajan; Maurice Chemweno; Leemer Cernohlavek; William Jacoby; Antonio Cardoso; Audrey Levine; Lisa Rhea; Karsten Baumann; R. K. M. Jayanty; James Flanagan; Menouer Boughedaoui; Rabah Kerbachi; Robert Joumard; Isaac Amponsah; Kenneth Harrison; Dimitris Rizos; Paul Ziehl; Cory Carter; Norman Eatough; Delbert Eatough; Neal Olson; Russell Long; Brett Grover; Michael Kleinman; Robert Cary; Philip Hopke; William Wilson; Hsun-Yu Lin; Wei-Chin Chen; Chung-Shin Yuan; Chung-Hsuang Hung; Yasuhiro Fukushima; Pao-Wen Liu; Jiun-Horng Tsai; Cheng Lee; Ting Tseng; Hung-Yueh Lin; Jehng-Jung Kao; Tim Keener

2008-01-01

37

Refeeding biogas digester solids  

Microsoft Academic Search

Biosolid, the digester residue from a biogas plant, must be of economical use to ensure the financial feasibility of biogas facilities. This paper sumarizes work performed for a Department of Energy study in the Imperial Valley of California. Feeding trials show that biosolid can only be used as a small proportion of feed rations. Apart from bacterial debris, biosolid is

Licht

1981-01-01

38

Long-term stability of thermophilic co-digestion submerged anaerobic membrane reactor encountering high organic loading rate, persistent propionate and detectable hydrogen in biogas.  

PubMed

The performance of thermophilic anaerobic co-digestion of coffee grounds and sludge using membrane reactor was investigated for 148days, out of a total research duration of 263days. The OLR was increased from 2.2 to 33.7kg-COD/m(3)d and HRT was shortened from 70 to 7days. A significant irreversible drop in pH confirmed the overload of reactor. Under a moderately high OLR of 23.6kg-COD/m(3)d, and with HRT and influent total solids of 10days and 150g/L, respectively, the COD removal efficiency was 44.5%. Hydrogen in biogas was around 100-200ppm, which resulted in the persistent propionate of 1.0-3.2g/L. The VFA consumed approximately 60% of the total alkalinity. NH4HCO3 was supplemented to maintain alkalinity. The stability of system relied on pH management under steady state. The 16SrDNA results showed that hydrogen-utilizing methanogens dominates the archaeal community. The propionate-oxidizing bacteria in bacterial community was insufficient. PMID:24090872

Qiao, Wei; Takayanagi, Kazuyuki; Niu, Qigui; Shofie, Mohammad; Li, Yu You

2013-09-13

39

High performance light water reactor  

Microsoft Academic Search

The objective of the high performance light water reactor (HPLWR) project is to assess the merit and economic feasibility of a high efficiency LWR operating at thermodynamically supercritical regime. An efficiency of approximately 44% is expected. To accomplish this objective, a highly qualified team of European research institutes and industrial partners together with the University of Tokyo is assessing the

D. Squarer; T. Schulenberg; D. Struwe; Y. Oka; D. Bittermann; N. Aksan; C. Maraczy; R. Kyrki-Rajamäki; A. Souyri; P. Dumaz

2003-01-01

40

Detailed analysis of metagenome datasets obtained from biogas-producing microbial communities residing in biogas reactors does not indicate the presence of putative pathogenic microorganisms  

PubMed Central

Background In recent years biogas plants in Germany have been supposed to be involved in amplification and dissemination of pathogenic bacteria causing severe infections in humans and animals. In particular, biogas plants are discussed to contribute to the spreading of Escherichia coli infections in humans or chronic botulism in cattle caused by Clostridium botulinum. Metagenome datasets of microbial communities from an agricultural biogas plant as well as from anaerobic lab-scale digesters operating at different temperatures and conditions were analyzed for the presence of putative pathogenic bacteria and virulence determinants by various bioinformatic approaches. Results All datasets featured a low abundance of reads that were taxonomically assigned to the genus Escherichia or further selected genera comprising pathogenic species. Higher numbers of reads were taxonomically assigned to the genus Clostridium. However, only very few sequences were predicted to originate from pathogenic clostridial species. Moreover, mapping of metagenome reads to complete genome sequences of selected pathogenic bacteria revealed that not the pathogenic species itself, but only species that are more or less related to pathogenic ones are present in the fermentation samples analyzed. Likewise, known virulence determinants could hardly be detected. Only a marginal number of reads showed similarity to sequences described in the Microbial Virulence Database MvirDB such as those encoding protein toxins, virulence proteins or antibiotic resistance determinants. Conclusions Findings of this first study of metagenomic sequence reads of biogas producing microbial communities suggest that the risk of dissemination of pathogenic bacteria by application of digestates from biogas fermentations as fertilizers is low, because obtained results do not indicate the presence of putative pathogenic microorganisms in the samples analyzed.

2013-01-01

41

Updated guidebook on biogas development  

SciTech Connect

On the practical aspects of small-scale biogas development suitable for use in rural areas of developing countries reviews biogas development throughout the ESCAP region and examines each of the steps involved in developing and operating a biogas plant. It details both the process and the microbiology of biogas fermentation and analyses the factors affecting gas plant design and operation. Also covered are the classification and design principles of plants, design, site, and site selection; starting and operating a gas plant; servicing and safety; and efficient plant performance. Also considered are the commercial uses of biogas and possible use of effluent.

Not Available

1985-01-01

42

Improving the Mixing Performances of Rice Straw Anaerobic Digestion for Higher Biogas Production by Computational Fluid Dynamics (CFD) Simulation.  

PubMed

As a lignocellulose-based substrate for anaerobic digestion, rice straw is characterized by low density, high water absorbability, and poor fluidity. Its mixing performances in digestion are completely different from traditional substrates such as animal manures. Computational fluid dynamics (CFD) simulation was employed to investigate mixing performances and determine suitable stirring parameters for efficient biogas production from rice straw. The results from CFD simulation were applied in the anaerobic digestion tests to further investigate their reliability. The results indicated that the mixing performances could be improved by triple impellers with pitched blade, and complete mixing was easily achieved at the stirring rate of 80 rpm, as compared to 20-60 rpm. However, mixing could not be significantly improved when the stirring rate was further increased from 80 to 160 rpm. The simulation results agreed well with the experimental results. The determined mixing parameters could achieve the highest biogas yield of 370 mL (g TS)(-1) (729 mL (g TSdigested)(-1)) and 431 mL (g TS)(-1) (632 mL (g TSdigested)(-1)) with the shortest technical digestion time (T 80) of 46 days. The results obtained in this work could provide useful guides for the design and operation of biogas plants using rice straw as substrates. PMID:23873639

Shen, Fei; Tian, Libin; Yuan, Hairong; Pang, Yunzhi; Chen, Shulin; Zou, Dexun; Zhu, Baoning; Liu, Yanping; Li, Xiujin

2013-07-20

43

Performance evaluation of a completely stirred anaerobic reactor treating pig manure at a low range of mesophilic conditions.  

PubMed

Many Chinese biogas plants run in the lower range of mesophilic conditions. This study evaluated the performance of a completely stirred anaerobic reactor treating pig manure at different temperatures (20, 28 and 38°C). The start-up phase of the reactor at 20°C was very long and extremely poor performance was observed with increasing organic loading rate (OLR). At an OLR of 4.3g ODML(-1)d(-1), methane production at 28°C was comparable (3% less) with that at 38°C, but the risk of acidification was high at 28°C. At low OLR (1.3g ODML(-1)d(-1)), the biogas process appeared stable at 28°C and gave same methane yields as compared to the reactor operating at 38°C. The estimated sludge yield at 28°C was 0.065g VSSg(-1) CODremoved, which was higher than that at 38°C (0.016g VSSg(-1) CODremoved). PMID:23842452

Guo, Jianbin; Dong, Renjie; Clemens, Joachim; Wang, Wei

2013-07-08

44

Biogas production from wheat straw in batch and UASB reactors: the roles of pretreatment and seaweed hydrolysate as a co-substrate.  

PubMed

This research evaluated biogas production in batch and UASB reactors from pilot-scale acid catalysed steam pretreated and enzymatic hydrolysed wheat straw. The results showed that the pretreatment was efficient and, a sugar yield of 95% was obtained. The pretreatment improved the methane yield (0.28 m(3)/kg VS(added)) by 57% compared to untreated straw. Treatment of the straw hydrolysate with nutrient supplementation in a UASB reactor resulted in a high methane production rate, 2.70 m(3)/m(3).d at a sustainable OLR of 10.4 kg COD/m(3).d and with a COD reduction of 94%. Alternatively, co-digestion of the straw and seaweed hydrolysates in a UASB reactor also maintained a stable anaerobic process and can thus reduce the cost of nutrients addition. We have shown that biogas production from wheat straw can be competitive by pretreatment, high methane production rate in UASB reactors and also by co-digestion with seaweed hydrolysate. PMID:23196235

Nkemka, Valentine Nkongndem; Murto, Marika

2012-11-02

45

Small-scale biogas applications  

SciTech Connect

Guidance is given through the exercise of determining whether a biogas system is worthwhile for a farm owner. After a brief description of anaerobic digestion and characteristics and economics of biogas, basic features of anaerobic digesters are discussed. The use of biogas is discussed, starting with gas collection at the digester and ending with waste heat recovery in cogeneration systems. Direct heating with biogas is also covered briefly. The parts of a working biogas system are discussed. Three different case studies are reviewed. Directions are offered for collecting site data and a method for performing a preliminary economic analysis of a given operation. Firms and consultants with experience in the design and construction of biogas systems are listed. (LEW)

Not Available

1981-08-01

46

Improvement of Biogas Production by Bioaugmentation  

PubMed Central

Biogas production technologies commonly involve the use of natural anaerobic consortia of microbes. The objective of this study was to elucidate the importance of hydrogen in this complex microbial food chain. Novel laboratory biogas reactor prototypes were designed and constructed. The fates of pure hydrogen-producing cultures of Caldicellulosiruptor saccharolyticus and Enterobacter cloacae were followed in time in thermophilic and mesophilic natural biogas-producing communities, respectively. Molecular biological techniques were applied to study the altered ecosystems. A systematic study in 5-litre CSTR digesters revealed that a key fermentation parameter in the maintenance of an altered population balance is the loading rate of total organic solids. Intensification of the biogas production was observed and the results corroborate that the enhanced biogas productivity is associated with the increased abundance of the hydrogen producers. Fermentation parameters did not indicate signs of failure in the biogas production process. Rational construction of more efficient and sustainable biogas-producing microbial consortia is proposed.

Kovacs, K. L.; Acs, N.; Kovacs, E.; Wirth, R.; Rakhely, G.; Strang, Orsolya; Herbel, Zsofia; Bagi, Z.

2013-01-01

47

Performance and kinetics of methanogenic fluidized bed reactors during start-up and steady-state phases  

SciTech Connect

This study characterizes the rate processes of substrate utilization, biogas production, and biomass accumulation in methanogenic fluidized bed reactors (FBRs), which use Manville R-633 beads as the growth support media, acetate enriched bacterial culture as the inoculum, and acetic acid as the sole substrate, during start-up and steady-state phases. Two start-up strategies, one based on maximum substrate utilization and the other on maximum substrate loading controlled by reactor pH, are evaluated for their efficacy in reactor start-up and effects on subsequent steady-state performance. An extensive laboratory study has been performed in order to obtain required experimental data for these tasks. The reactors attain excellent TOC (total organic carbon) removal (i.e., >97% at a feed concentration of 5,200 mg/L) and stable biogas production (i.e., 0.9 L CH[sub 4] per gram TOC of removed) at the early stage of the start-up process, regardless of the strategies adopted. Significant losses of growth support media and bacterial cells caused by gas effervescence limit the maximum loading that can safely be applied during the start-up phase. TOC removal, biogas production rate, biogas composition, and biofilm detachment rate during the steady-state phase remain essentially identically to those observed during the start-up process. However, appreciable decreases in immobilized bacterial cell masses are observed when the loading is reduced from 6 to 2 g TOC/L-day. These observations indicate that the reactors are operated under severe substrate limited conditions at the lower loading that reduces the overall bacterial activity. The bacterial cells cultivated under substrate rich conditions are more susceptible to these starvation conditions. However, they are more capable of handling a larger increase in organic loading, as indicated by their higher specific substrate utilization rates measured under batch conditions.

Yen, H.

1992-01-01

48

EU Agro Biogas Project  

Microsoft Academic Search

EU-AGRO-BIOGAS is a European Biogas initiative to improve the yield of agricultural biogas plants in Europe, to optimise biogas technology and processes and to improve the efficiency in all parts of the production chain from feedstock to biogas utilisation. Leading European research institutions and universities are cooperating with key industry partners in order to work towards sustainable biogas production in

T. Amon; H. Mayr; M. Eder; P. Hobbs; S. Rao Ravella; U. Roth; A. Niebaum; H. Doehler; P. Weiland; E. Abdoun; A. Moser; M. Lyson; M. Heiermann; M. Plöchl; J. Budde; A. Schattauer; T. Suarez; H. Möller; A. Ward; F. Hillen; P. Sulima; A. Oniszk-Polplawska; P. Krampe; Z. Pastorek; J. Kara; J. Mazancova; Dooren van H. J. C; C. Wim; F. Gioelli; P. Balsari

2009-01-01

49

BIOGAS Process development  

Microsoft Academic Search

The overall objective of the program is to demonstrate and commercialize the IGT two-phase BIOGAS Process for optimized methane production from, and simultaneous stabilization of, municipal solid waste (MSW). The specific objective of the current program is to conduct a laboratory-scale investigation of simple, cost-effective feed pretreatment techniques and selected digestion reactor designs to optimize methane production from MSW-sludge blends,

S. Ghosh; M. C. Mensinger; A. Sajjad; M. P. Henry

1984-01-01

50

Optimization of biogas production from wheat straw stillage in UASB reactor  

Microsoft Academic Search

In the present study, thermophilic anaerobic digestion of wheat straw stillage was investigated. Methane potential of stillage was determined in batch experiments at two different substrate concentrations. Results showed that higher methane yields of 324ml\\/g-(volatile solids) VSadded were obtained at stillage concentrations of 12.8g-VS\\/L than at 25.6g-VS\\/l. Continuous anaerobic digestion of stillage was performed in an up-flow anaerobic sludge blanket

Prasad Kaparaju; María Serrano; Irini Angelidaki

2010-01-01

51

Breeding maize as biogas substrate in Central Europe: II. Quantitative-genetic parameters for inbred lines and correlations with testcross performance.  

PubMed

Breeding maize for use as a biogas substrate (biogas maize) has recently gained considerable importance. To optimize hybrid breeding programs, information about line per se performance (LP) of inbreds and its relation to their general combining ability (GCA) is required. The objectives of our research were to (1) estimate variance components and heritability of LP for agronomic and quality traits relevant to biogas production, (2) study correlations among traits as well as between LP and GCA, and (3) discuss implications for breeding of biogas maize. We evaluated 285 diverse dent maize inbred lines in six environments. Data were recorded on agronomic and quality traits, including dry matter yield (DMY), methane fermentation yield (MFY), and their product, methane yield (MY), as the main target trait. In agreement with observations made for GCA in a companion study, variation in MY was mainly determined by DMY. MFY, which showed moderate correlation with lignin but only weak correlation with starch, revealed only low genotypic variation. Thus, our results favor selection of genotypes with high DMY and less focus on ear proportion for biogas maize. Genotypic correlations between LP and GCA [r (g) (LP, GCA)] were highest (?0.94) for maturity traits (days to silking, dry matter concentration) and moderate (?0.65) for DMY and MY. Multistage selection is recommended. Selection for GCA of maturity traits, plant height, and to some extent also quality traits and DMY on the level of LP looks promising. PMID:22159757

Grieder, Christoph; Dhillon, Baldev S; Schipprack, Wolfgang; Melchinger, Albrecht E

2011-12-13

52

Biogas in France  

SciTech Connect

Biogas is produced by the methanation of organic matter. It involves a process of fermentation carried out in an air-free environment by populations of bacteria living in symbiosis. The methane content of biogas is high (50 - 80%) and it constitutes an advantageous solution to the problems of energy supply in developing countries and in rural zones where natural gas is not distributed. Everywhere, methanation contributes to the control of environmental pollution, and biogas production is sometimes accompanied by the output of high quality fertilizer. Over the last few years, France has engaged in a certain number of research projects for the development of high performance techniques in the field of biogas, and the gas industry has made a considerable contribution in the setting up of a certain number of installations. The researchers and manufacturers involved have therefore acquired wide experience in this domain. Solutions, original both in technical and economic terms, have been found, and they are henceforth available to all those countries who wish to produce and exploit biogas.

Donat, G.

1988-01-01

53

Janata biogas technology and fodder production  

SciTech Connect

An effective bio-gas program leads to efficient use of cow dung for gas recovery and partial supplement to plant nutrient requirements. Bio-gas program leads to improvement in rural living including rural sanitation. The Janata biogas plant designed by the State Planning Institute, Lucknow, based on biogas technology, has proved to be efficient and economical. This book contains the various papers presented at the seminar held to review this technology. The various topics covered are: Status of Biogas Program in India; Role of Extension Agencies in Developing Program of Energy Utilization; Introduction to Drumless Biogas Plant; Principles and Application of Anaerobic Fermentation and Biogas Production, Operational System of Gobar Gas in Rural India; Complete Recycling of Cattle Shed Wastes through Biogas Plant; Chemical Composition of Cattle Excreta and Its Manurial Value; Profitability of Biogas Plant; Biogas Production from Various Organic Wastes; Performance of Janata Biogas Plant and Biogas Utilization in Appliances; Utilization of Solar Energy for Domestic Purposes; and Conservation of Forages. Plant requirements and cost estimates have been given for several units.

Neelakantan, S.

1981-01-01

54

A pyrosequencing-based metagenomic study of methane-producing microbial community in solid-state biogas reactor  

PubMed Central

Background A solid-state anaerobic digestion method is used to produce biogas from various solid wastes in China but the efficiency of methane production requires constant improvement. The diversity and abundance of relevant microorganisms play important roles in methanogenesis of biomass. The next-generation high-throughput pyrosequencing platform (Roche/454 GS FLX Titanium) provides a powerful tool for the discovery of novel microbes within the biogas-generating microbial communities. Results To improve the power of our metagenomic analysis, we first evaluated five different protocols for extracting total DNA from biogas-producing mesophilic solid-state fermentation materials and then chose two high-quality protocols for a full-scale analysis. The characterization of both sequencing reads and assembled contigs revealed that the most prevalent microbes of the fermentation materials are derived from Clostridiales (Firmicutes), which contribute to degrading both protein and cellulose. Other important bacterial species for decomposing fat and carbohydrate are Bacilli, Gammaproteobacteria, and Bacteroidetes (belonging to Firmicutes, Proteobacteria, and Bacteroidetes, respectively). The dominant bacterial species are from six genera: Clostridium, Aminobacterium, Psychrobacter, Anaerococcus, Syntrophomonas, and Bacteroides. Among them, abundant Psychrobacter species, which produce low temperature-adaptive lipases, and Anaerococcus species, which have weak fermentation capabilities, were identified for the first time in biogas fermentation. Archaea, represented by genera Methanosarcina, Methanosaeta and Methanoculleus of Euryarchaeota, constitute only a small fraction of the entire microbial community. The most abundant archaeal species include Methanosarcina barkeri fusaro, Methanoculleus marisnigri JR1, and Methanosaeta theromphila, and all are involved in both acetotrophic and hydrogenotrophic methanogenesis. Conclusions The identification of new bacterial genera and species involved in biogas production provides insights into novel designs of solid-state fermentation under mesophilic or low-temperature conditions.

2013-01-01

55

Fast Reactor Fuel Type and Reactor Safety Performance  

SciTech Connect

Fast Reactor Fuel Type and Reactor Safety Performance R. Wigeland , Idaho National Laboratory J. Cahalan, Argonne National Laboratory The sodium-cooled fast neutron reactor is currently being evaluated for the efficient transmutation of the highly-hazardous, long-lived, transuranic elements that are present in spent nuclear fuel. One of the fundamental choices that will be made is the selection of the fuel type for the fast reactor, whether oxide, metal, carbide, nitride, etc. It is likely that a decision on the fuel type will need to be made before many of the related technologies and facilities can be selected, from fuel fabrication to spent fuel reprocessing. A decision on fuel type should consider all impacts on the fast reactor system, including safety. Past work has demonstrated that the choice of fuel type may have a significant impact on the severity of consequences arising from accidents, especially for severe accidents of low probability. In this paper, the response of sodium-cooled fast reactors is discussed for both oxide and metal fuel types, highlighting the similarities and differences in reactor response and accident consequences. Any fast reactor facility must be designed to be able to successfully prevent, mitigate, or accommodate all consequences of potential events, including accidents. This is typically accomplished by using multiple barriers to the release of radiation, including the cladding on the fuel, the intact primary cooling system, and most visibly the reactor containment building. More recently, this has also included the use of ‘inherent safety’ concepts to reduce or eliminate the potential for serious damage in some cases. Past experience with oxide and metal fuel has demonstrated that both fuel types are suitable for use as fuel in a sodium-cooled fast reactor. However, safety analyses for these two fuel types have also shown that there can be substantial differences in accident consequences due to the neutronic and thermophysical properties of the fuel and their compatibility with the reactor coolant, with corresponding differences in the challenges presented to the reactor developers. Accident phenomena are discussed for the sodium-cooled fast reactor based on the mechanistic progression of conditions from accident initiation to accident termination, whether a benign state is achieved or more severe consequences are expected. General principles connecting accident phenomena and fuel properties are developed from the oxide and metal fuel safety analyses, providing guidelines that can be used as part of the evaluation for selection of fuel type for the sodium-cooled fast reactor.

R. Wigeland; J. Cahalan

2009-09-01

56

New Industrially Produced Biogas Technology for Developing Countries  

Microsoft Academic Search

To promote a rapid dissemination of biogas technology in developing countries, a new biogas reactor with unconventional design was proposed for industrial production. The reactor consists of two cylindrical panels and a spherical sheet made of glassfiber reinforced polyester. In operation, the reactor is placed on an elevated layer of sand above the ground and is exposed to solar heating.

JOSEF ZUBR

1993-01-01

57

Optimisation of biogas production from manure through serial digestion: Lab-scale and pilot-scale studies  

Microsoft Academic Search

In the present study, the possibility of optimizing biogas production from manure by serial digestion was investigated. In the lab-scale experiments, process performance and biogas production of serial digestion, two methanogenic continuously stirred tank reactors (CSTR) connected in series, was compared to a conventional one-step CSTR process. The one-step process was operated at 55°C with 15d HRT and 5l working

Prasad Kaparaju; Lars Ellegaard; Irini Angelidaki

2009-01-01

58

Biological hydrogen production in a UASB reactor with granules. II: Reactor performance in 3-year operation.  

PubMed

The experiment was conducted to evaluate the performance of an upflow anaerobic sludge blanket (UASB) with granules for H(2) production from a sucrose-rich synthetic wastewater at various substrate concentrations (5.33-28.07 g-COD/L) and hydraulic retention times (HRTs) (3-30 h) for over 3 years. The kinetics of H(2) production was evaluated, and the sludge yield and endogenous decay coefficient of the H(2)-producing granules were estimated to be 0.334 g-VSS/g-COD and 0.004/h, respectively. Based on Gibbs free energy calculations, the formation thermodynamics of caproate, an important aqueous product, were analyzed. Experimental results show that the H(2) partial pressure in biogas decreased with increasing substrate concentration, but was not sensitive to the variation of HRT in a range of 6-22 h. The H(2) production rate increased with increasing substrate concentration, but decreased with increasing HRT. The H(2) yield was in the range of 0.49-1.44 mol-H(2)/mol-glucose. Acetate, butyrate, caporate, and ethanol were the main aqueous products in the reactor, and their concentrations were dependent on both substrate concentration and HRT. An elevated substrate concentration resulted in a shift of fermentation from butyrate- to caporate-type in the reactor and the formation of caproate was dependent on the H(2) partial pressure. The 3-year experimental results demonstrate that H(2) could be produced continuously and stably from the acidogenic-granule-based UASB reactor. PMID:16615161

Yu, Han-Qing; Mu, Yang

2006-08-01

59

BIOGAS Process development  

SciTech Connect

The overall objective of the program is to demonstrate and commercialize the IGT two-phase BIOGAS Process for optimized methane production from, and simultaneous stabilization of, municipal solid waste (MSW). The specific objective of the current program is to conduct a laboratory-scale investigation of simple, cost-effective feed pretreatment techniques and selected digestion reactor designs to optimize methane production from MSW-sludge blends, and to select the best pretreatment and digestion conditions for testing during the subsequent program for process development unit (PDU) operation. A significant portion of the program efforts to date has been directed at evaluating and/or developing feeding, mixing and discharging systems for handling high concentration, large particle size RDF slurries for anaerobic digestion processes. The performance of such processes depends significantly on the operational success of these subsystems. The results of the subsystem testing have been implemented in the design and operation of the 10-L, 20-L, and 125-L digesters. These results will also be utilized to design the CSTR and the upflow digesters of a large two-phase system. Data collected during the initial phase of this research showed in general that methane production from RDF decreased as the loading rate was increased. Thermophilic digestion did not appear to be significantly better than mesophlic digestion. 9 figures, 3 tables.

Ghosh, S.; Mensinger, M.C.; Sajjad, A.; Henry, M.P.

1984-01-01

60

EU Agro Biogas Project  

Microsoft Academic Search

EU-AGRO-BIOGAS is a European Biogas initiative to improve the yield of agricultural biogas plants in Europe, to optimise biogas technology and processes and to improve the efficiency in all parts of the production chain from feedstock to biogas utilisation. Leading European research institutions and universities are cooperating with key industry partners in order to work towards a sustainable Europe. Fourteen

T. Amon; H. Mayr; M. Eder; P. Hobbs; S. Rao Ravella; U. Roth; A. Niebaum; H. Doehler; P. Weiland; E. Abdoun; A. Moser; M. Lyson; M. Heiermann; M. Plöchl; J. Budde; A. Schattauer; T. Suarez; H. Möller; A. Ward; F. Hillen; P. Sulima; A. Oniszk-Polplawska; P. Krampe; Z. Pastorek; J. Kara; J. Mazancova; Dooren van H. J. C; C. Wim; F. Gioelli; P. Balsari

2009-01-01

61

Performance of a biogas upgrading process based on alkali absorption with regeneration using air pollution control residues.  

PubMed

This work analyzes the performance of an innovative biogas upgrading method, Alkali absorption with Regeneration (AwR) that employs industrial residues and allows to permanently store the separated CO2. This process consists in a first stage in which CO2 is removed from the biogas by means of chemical absorption with KOH or NaOH solutions followed by a second stage in which the spent absorption solution is contacted with waste incineration Air Pollution Control (APC) residues. The latter reaction leads to the regeneration of the alkali reagent in the solution and to the precipitation of calcium carbonate and hence allows to reuse the regenerated solution in the absorption process and to permanently store the separated CO2 in solid form. In addition, the final solid product is characterized by an improved environmental behavior compared to the untreated residues. In this paper the results obtained by AwR tests carried out in purposely designed demonstrative units installed in a landfill site are presented and discussed with the aim of verifying the feasibility of this process at pilot-scale and of identifying the conditions that allow to achieve all of the goals targeted by the proposed treatment. Specifically, the CO2 removal efficiency achieved in the absorption stage, the yield of alkali regeneration and CO2 uptake resulting for the regeneration stage, as well as the leaching behavior of the solid product are analyzed as a function of the type and concentration of the alkali reagent employed for the absorption reaction. PMID:24045173

Baciocchi, Renato; Carnevale, Ennio; Costa, Giulia; Gavasci, Renato; Lombardi, Lidia; Olivieri, Tommaso; Zanchi, Laura; Zingaretti, Daniela

2013-09-14

62

Performance and characterization of a newly developed self-agitated anaerobic reactor with biological desulfurization.  

PubMed

The continuous operation of a newly developed methane fermentation reactor, which requires no electricity for the agitation of the fermentation liquid was investigated, and the extent of the biological desulfurization was monitored. Inside the reactor, the continual change in the liquid level and the self-agitation, occurring between 5 and 16 times every day, distributed the organic load near the inlet port of the reactor, as well as providing a nutrient supply to the hydrogen sulfide oxidizing bacteria. At different COD(Cr) loading rates (5, 7, 10 kg m(3)d(-1)), the reactor achieved a biogas production yield of 0.72-0.82 m(3)g(-1)-TS, a COD(Cr) reduction of 79.4-85.5% and an average of 99% hydrogen sulfide removal. This investigation demonstrated that the self-agitated reactor is comparable in digestion performance to the completely stirred tank reactor (CSTR) investigated in a previous study, and that the desulfurization performance was significantly enhanced compared to the CSTR. PMID:21398119

Kobayashi, Takuro; Li, Yu-You

2011-02-02

63

Evidence of anaerobic syntrophic acetate oxidation in biogas batch reactors by analysis of (13)C carbon isotopes.  

PubMed

Between 2008 and 2010 various batch experiments were carried out to study the stable carbon isotopic composition of biogas (CH4 and CO2) produced from (i) pure sludge and (ii) sludge including maize. From the evolution of the natural isotopic signature, a temporal change of methanogenic pathways could be detected for the treatment with maize showing that a dominance in acetotrophic methanogenesis was replaced by a mixture of hydrogenotrophic and acetotrophic methanogenesis. For pure sludge, hydrogenotrophic methanogenesis was the dominant or probably exclusive pathway. Experiments with isotopically labelled acetate (99% (13)CH3COONa and 99% [Formula: see text]COONa) indicated a significant contribution of syntrophic acetate oxidation (SAO) for all the investigated treatments. In the case of pure sludge, experiments from 2008 showed that acetate was almost entirely oxidised to CO2, i.e. acetotrophic methanogenesis was negligible. However, in 2010, the sludge showed a clear dominance in acetotrophic methanogenesis with a minor contribution by SAO indicating a significant change in the metabolic character. Our results indicate that SAO during anaerobic degradation of maize might be a significant process that needs to be considered in biogas research. PMID:23781862

Polag, Daniela; Heuwinkel, Hauke; Laukenmann, Stephan; Greule, Markus; Keppler, Frank

2013-06-20

64

Reactor performance and bacterial pathogen removal in response to sludge retention time in a mesophilic anaerobic digester treating sewage sludge.  

PubMed

The effects of sludge retention time (SRT) on reactor performance and bacterial pathogen removal of sludge mesophilic anaerobic digestion (MAD) were investigated in a continuous stirred tank reactor. The average volatile solids removal remained around 20% and the biogas production rate varied from 100 to 132ml/ld. The MAD process was efficient to remove Salmonella sp. and Escherichia coli with removal efficiencies increased with SRT from 11d, 16d to 25d. However, the Shigella sp. removal was insignificant. The difference in the resistance of the three pathogens to sludge MAD process is helpful to the selection of pathogen indicators in the biosolids. Log reduction of pathogens determined by MPN was much higher than the data by quantitative PCR, suggesting the presence of viable but non-culturable pathogen cells. This study confirms that the control of appropriate SRT for sludge MAD should take both reactor performance and pathogen removal into account. PMID:22197074

Chen, Yan; Fu, Bo; Wang, Yan; Jiang, Qian; Liu, He

2011-12-04

65

Quantification of Syntrophic Fatty Acid-?-Oxidizing Bacteria in a Mesophilic Biogas Reactor by Oligonucleotide Probe Hybridization  

PubMed Central

Small-subunit rRNA sequences were obtained for two saturated fatty acid-?-oxidizing syntrophic bacteria, Syntrophomonas sapovorans and Syntrophomonas wolfei LYB, and sequence analysis confirmed their classification as members of the family Syntrophomonadaceae. S. wolfei LYB was closely related to S. wolfei subsp. wolfei, but S. sapovorans did not cluster with the other members of the genus Syntrophomonas. Five oligonucleotide probes targeting the small-subunit rRNA of different groups within the family Syntrophomonadaceae, which contains all currently known saturated fatty acid-?-oxidizing syntrophic bacteria, were developed and characterized. The probes were designed to be specific at the family, genus, and species levels and were characterized by temperature-of-dissociation and specificity studies. To demonstrate the usefulness of the probes for the detection and quantification of saturated fatty acid-?-oxidizing syntrophic bacteria in methanogenic environments, the microbial community structure of a sample from a full-scale biogas plant was determined. Hybridization results with probes for syntrophic bacteria and methanogens were compared to specific methanogenic activities and microbial numbers determined with most-probable-number estimates. Most of the methanogenic rRNA was comprised of Methanomicrobiales rRNA, suggesting that members of this order served as the main hydrogen-utilizing microorganisms. Between 0.2 and 1% of the rRNA was attributed to the Syntrophomonadaceae, of which the majority was accounted for by the genus Syntrophomonas.

Hansen, Kaare H.; Ahring, Birgitte K.; Raskin, Lutgarde

1999-01-01

66

Quantification of syntrophic fatty acid-{beta}-oxidizing bacteria in a mesophilic biogas reactor by oligonucleotide probe hybridization  

SciTech Connect

Small-subunit rRNA sequences were obtained for two saturated fatty acid-{beta}-oxidizing syntrophic bacteria, Syntrophomonas sapovorans and Syntrophomonas wolfei LYB, and sequence analysis confirmed their classification as members of the family Syntrophomonadaceae. S.wolfei LYB was closely related to S.wolfei subsp. solfei, but S. sapovorans did not cluster with the other members of the genus Syntrophomonas. Five oligonucleotide probes targeting the small-subunit rRNA of different groups within the family Syntrophomonadaceae, which contains all currently known saturated fatty acid-{beta}-oxidizing syntrophic bacteria, were developed and characterized. The probes were designed to be specific at the family, genus, and species levels and were characterized by temperature-of-dissociation and specificity studies. To demonstrate the usefulness of the probes for the detection and quantification of saturated fatty acid-{beta}-oxidizing syntrophic bacteria in methanogenic environments, the microbial community structure of a sample from a full-scale biogas plant was determined. Hybridization results with probes for syntrophic bacteria and methanogens were compared to specific methanogenic activities and microbial numbers determined with most-probable-number estimates. Most of the methanogenic rRNA was comprised of Methanomicrobiales rRNA, suggesting that members of this order served as the main hydrogen-utilizing microorganisms. Between 0.2 and 1% of the rRNA was attributed to the Syntrophomonadaceae, or which the majority was accounted for by the genus Syntrophomonas.

Hansen, K.H.; Ahring, B.K.; Raskin, L.

1999-11-01

67

Performance of a Flameless combustion furnace using biogas and natural gas  

Microsoft Academic Search

Flameless combustion technology has proved to be flexible regarding the utilization of conventional fuels. This flexibility is associated with the main characteristic of the combustion regime, which is the mixing of the reactants above the autoignition temperature of the fuel. Flameless combustion advantages when using conventional fuels are a proven fact. However, it is necessary to assess thermal equipments performance

A. F. Colorado; B. A. Herrera; A. A. Amell

2010-01-01

68

Biogas from waste in Belgium  

SciTech Connect

This article describes plans for a dry anaerobic composting plant in Brecht, Belgium. The new plant will utilize dry conditions and thermophilic temperatures to produce an average of 6 to 8 volumes of biogas per volume of reactor per day could be produced from vegetable, fruit, garden and paper waste, and a soil amendment from the organic fraction of municipal solid waste according to researchers.

Not Available

1991-08-01

69

Methods for increasing the biogas potential from the recalcitrant organic matter contained in manure  

Microsoft Academic Search

The biogas potential of manure could be significantly increased by treatment of the recalcitrant organic matter (biofibers) contained in the manure. Several treatment methods were tested. Mechanical maceration resulted in an average increase of the biogas potential of approximately 17% as shown by the continuous stirred reactor experiment. In general the smaller the fibers the higher the biogas potential was.

I. Angelidaki; B. K. Ahring

70

A New and Sound Technology for Biogas from Solid Waste and Biomass  

Microsoft Academic Search

Organic waste, as a main constituent of municipal solid waste, has as well as solid biomass a high potential for biogas generation.\\u000a Despite the importance of biogas generation from these materials, the availability of large-scale biogas processes lacks behind\\u000a the demand. A newly developed double-stage solid–liquid biogas process, consisting of an open hydrolysis stage and a fixed-bed\\u000a methane reactor, allows

G. Busch; J. Großmann; M. Sieber; M. Burkhardt

2009-01-01

71

Performance of metallic fuels in liquid-metal fast reactors  

Microsoft Academic Search

Interest in metallic fuels for liquid-metal fast reactors has come full circle. Metallic fuels are once again a viable alternative for fast reactors because reactor outlet temperature of interest to industry are well within the range where metallic fuels have demonstrated high burnup and reliable performance. In addition, metallic fuel is very tolerant of off-normal events of its high thermal

B. R. Seidel; L. C. Walters; J. H. Kittel

1984-01-01

72

Implementation and Utilization of Biogas.  

National Technical Information Service (NTIS)

A review of the characteristics and problems encountered during production, transportation and utilization of biogas is presented: chemical analysis of the biogas (Instruments), corrosiveness of biogas and its effects on ducts, design of the ducts and duc...

J. P. Perret

1983-01-01

73

Biogas Plasticization Coupled Anaerobic Digestion: Continuous Flow Anaerobic Pump Test Results  

Microsoft Academic Search

In this investigation, the Anaerobic Pump (®TAP) and a conventional continuous flow stirred tank reactor (CFSTR) were tested\\u000a side by side to compare performance. TAP integrates anaerobic digestion (AD) with biogas plasticization–disruption cycle to\\u000a improve mass conversion to methane. Both prototypes were fed a “real world” 50:50 mixture of waste-activated sludge (WAS)\\u000a and primary sludge and operated at room temperature

Keith A. Schimel; David R. Boone

2010-01-01

74

Integrated biogas systems  

NASA Astrophysics Data System (ADS)

Integrated biogas systems as alternatives to fossil fuels in Sri Lanka are considered from standpoints of population growth, land availability, and employment opportunities. Agricultural practices would be improved by use of chemical fertilizers, and health/nutrition problems be alleviated by using biogas systems. Fuel for cooking and rural industries will become more easily available; water weeds, such as water hyacinth and salvinia which pose a threat to waterways and rice paddy lands could be used for the production of biogas and fertilizers. A concept of an integrated biogas system comprising photosynthesis and anaerobic degradation processes to produce food and energy is presented.

Amaratunga, M.

1980-01-01

75

Rural Use of Biogas.  

National Technical Information Service (NTIS)

A manual on the production and use of biogas in the rural areas of China is presented. The importance of biogas production for improving the agricultural level is stressed and its properties are explained. The basic principles in the construction and main...

1976-01-01

76

Performance comparison of two anammox reactors: SBR and UBF  

Microsoft Academic Search

The performance of two selected high rate anammox reactors, i.e. sequencing batch reactor (SBR) and an upflow biofilter (UBF) were compared operating them simultaneously at 30°C. The sludge from anaerobic digester of a municipal wastewater treatment plant was used for inoculation and synthetic wastewater was fed to both reactors during the experiment. During start-up, the nitrogen loading rate (NLR) was

Ren-Cun Jin; Ping Zheng; An-Hui Hu; Qaisar Mahmood; Bao-Lan Hu; Ghulam Jilani

2008-01-01

77

Baffle effects on performance of catalytic circulating fluidized bed reactor  

Microsoft Academic Search

This paper reports on baffle effects on the performance of a catalytic circulating fluidized bed reactor which were examined experimentally. The circulating fluidized bed reactor or riser was 102 mm in diameter and 6.32 m in height. Reaction was the catalytic decomposition of ozone using FCC particles with a mean diameter of 89 [mu]m, impregnated with ferric oxide as catalysts.

Peijun Jiang; Hsiaotao Bi; Rong-Her Jean; Liang-Shih Fan

1991-01-01

78

Metaproteome analysis to determine the metabolically active part of a thermophilic microbial community producing biogas from agricultural biomass.  

PubMed

Complex consortia of microorganisms are responsible for biogas production. A lot of information about the taxonomic structure and enzymatic potential of such communities has been collected by a variety of gene-based approaches, yet little is known about which of all the assumable metabolic pathways are active throughout the process of biogas formation. To tackle this problem, we established a protocol for the metaproteomic analysis of samples taken from biogas reactors fed with agricultural biomass. In contrast to previous studies where an anaerobic digester was fed with synthetic wastewater, the complex matrix in this study required the extraction of proteins with liquid phenol and the application of paper bridge loading for 2-dimensional gel electrophoresis. Proteins were subjected to nanoHPLC (high-performance liquid chromatography) coupled to tandem mass spectrometry for characterization. Several housekeeping proteins as well as methanogenesis-related enzymes were identified by a MASCOT search and de novo sequencing, which proved the feasibility of our approach. The establishment of such an approach is the basis for further metaproteomic studies of biogas-producing communities. In particular, the apparent status of metabolic activities within the communities can be monitored. The knowledge collected from such experiments could lead to further improvements of biogas production. PMID:22690648

Hanreich, Angelika; Heyer, Robert; Benndorf, Dirk; Rapp, Erdmann; Pioch, Markus; Reichl, Udo; Klocke, Michael

2012-06-12

79

Improved biogas production from rice straw by co-digestion with kitchen waste and pig manure.  

PubMed

In order to investigate the effect of feedstock ratios in biogas production, anaerobic co-digestions of rice straw with kitchen waste and pig manure were carried out. A series of single-stage batch mesophilic (37±1°C) anaerobic digestions were performed at a substrate concentration of 54g/L based on volatile solids (VS). The results showed that the optimal ratio of kitchen waste, pig manure, and rice straw was 0.4:1.6:1, for which the C/N ratio was 21.7. The methane content was 45.9-70.0% and rate of VS reduction was 55.8%. The biogas yield of 674.4L/kgVS was higher than that of the digestion of rice straw or pig manure alone by 71.67% and 10.41%, respectively. Inhibition of biogas production by volatile fatty acids (VFA) occurred when the addition of kitchen waste was greater than 26%. The VFA analysis showed that, in the reactors that successfully produced biogas, the dominant intermediate metabolites were propionate and acetate, while they were lactic acid, acetate, and propionate in the others. PMID:23790673

Ye, Jingqing; Li, Dong; Sun, Yongming; Wang, Guohui; Yuan, Zhenhong; Zhen, Feng; Wang, Yao

2013-06-20

80

Light Water Reactor Pressure Isolation Valve Performance Testing.  

National Technical Information Service (NTIS)

The Light Water Reactor Valve Performance Testing Program was initiated by the NRC to evaluate leakage as an indication of valve condition, provide input to Section XI of the ASME Code, evaluate motor signature testing to measure valve operability, evalua...

H. H. Neely N. M. Jeanmougin J. J. Corugedo

1990-01-01

81

Biogas - Not Just Technology.  

National Technical Information Service (NTIS)

Anaerobic digestion of organic matter produces biogas, which is a fuel, and digested sludge, which can be used as fertilizer. It also improves hygienic conditions by killing off pathogenic bacteria and parasites. These benefits are obvious in the rural ar...

A. Ellegaard A. Jonsson A. Zetterqvist

1983-01-01

82

Effect of some operating parameters on biogas production rate  

Microsoft Academic Search

In order to enhance the performance of a biogas generation process and prevent process failure, certain operataing parameters need to be controlled. This article presents the results of a series of studies in which the effect of temperature, pH, carbon -nitrogen ratio and retention time on biogas production from cowdung were investigated

A. S. Sambo; B. Garba; B. G. Danshehu

1995-01-01

83

Comparative study of biogas production from different waste materials  

Microsoft Academic Search

Experimental studies have been performed to find the biogas generation capacity of each mixture and its individual components of various categories of waste materials, like animal dungs, kitchen wastes, waste flowers, etc. Hence, the best waste material, that can produce the maximum amount of biogas from each category of waste materials, has been found at a specific temperature of 37°C.

Tanusri Mandal; N. K. Mandal

1997-01-01

84

Co-generation of electricity and heat from biogas  

SciTech Connect

Biogas powered co-generation of electricity and hot water is being documented in a full scale demonstration with a 25 kW capacity system. The performance characteristics and effects of operating on biogas for 1400 hours are presented in this paper.

Koelsch, R.K.; Cummings, R.J.; Harrison, C.E.; Jewell, W.J.

1982-12-01

85

Transient two-phase performance of LOFT reactor coolant pumps  

SciTech Connect

Performance characteristics of Loss-of-Fluid Test (LOFT) reactor coolant pumps under transient two-phase flow conditions were obtained based on the analysis of two large and small break loss-of-coolant experiments conducted at the LOFT facility. Emphasis is placed on the evaluation of the transient two-phase flow effects on the LOFT reactor coolant pump performance during the first quadrant operation. The measured pump characteristics are presented as functions of pump void fraction which was determined based on the measured density. The calculated pump characteristics such as pump head, torque (or hydraulic torque), and efficiency are also determined as functions of pump void fractions. The importance of accurate modeling of the reactor coolant pump performance under two-phase conditions is addressed. The analytical pump model, currently used in most reactor analysis codes to predict transient two-phase pump behavior, is assessed.

Chen, T.H.; Modro, S.M.

1983-01-01

86

BIOGAS for Brazil  

Microsoft Academic Search

The Brazilian government is using IGT's BIOGAS process as the basis for a new biomass-gasification plant to be constructed at Sao Paulo. Sited adjacent to a wastewater-treatment plant and a composting plant on the bank of the Tiete River, the BIOGAS facility will convert up to 770 tons (700 metric tons)\\/day of municipal solid wastes (MSW) to methane via anaerobic

2009-01-01

87

Production and energetic use of biogas from energy crops and wastes in Germany  

Microsoft Academic Search

The production of biogas for reducing fossil CO2 emissions is one of the key strategic issues of the German government and has resulted in the development of new process\\u000a techniques and new technologies for the energetic use of biogas. Progress has been made in cultivating energy crops for biogas\\u000a production, in using new reactor systems for anaerobic digestion, and in

Peter Weiland

2003-01-01

88

Optimization of biogas production from olive-oil mill wastewater, by codigesting with diluted poultry-manure  

Microsoft Academic Search

Optimization of biogas production from olive-mill wastewater (OMW) was attempted by codigesting with diluted poultry-manure (DPM) at mesophilic conditions. A series of laboratory experiments were performed in continuously-operating reactors, fed with mixtures of OMW and DPM at various concentrations. It was concluded that codigestion of OMW with DPM is possible without any dilution of OMW or addition of any chemicals.

John Gelegenis; Dimitris Georgakakis; Irini Angelidaki; Nicholetta Christopoulou; Maria Goumenaki

2007-01-01

89

Polyphasic Analyses of Methanogenic Archaeal Communities in Agricultural Biogas Plants?  

PubMed Central

Knowledge of the microbial consortia participating in the generation of biogas, especially in methane formation, is still limited. To overcome this limitation, the methanogenic archaeal communities in six full-scale biogas plants supplied with different liquid manures and renewable raw materials as substrates were analyzed by a polyphasic approach. Fluorescence in situ hybridization (FISH) was carried out to quantify the methanogenic Archaea in the reactor samples. In addition, quantitative real-time PCR (Q-PCR) was used to support and complete the FISH analysis. Five of the six biogas reactors were dominated by hydrogenotrophic Methanomicrobiales. The average values were between 60 to 63% of archaeal cell counts (FISH) and 61 to 99% of archaeal 16S rRNA gene copies (Q-PCR). Within this order, Methanoculleus was found to be the predominant genus as determined by amplified rRNA gene restriction analysis. The aceticlastic family Methanosaetaceae was determined to be the dominant methanogenic group in only one biogas reactor, with average values for Q-PCR and FISH between 64% and 72%. Additionally, in three biogas reactors hitherto uncharacterized but potentially methanogenic species were detected. They showed closest accordance with nucleotide sequences of the hitherto unclassified CA-11 (85%) and ARC-I (98%) clusters. These results point to hydrogenotrophic methanogenesis as a predominant pathway for methane synthesis in five of the six analyzed biogas plants. In addition, a correlation between the absence of Methanosaetaceae in the biogas reactors and high concentrations of total ammonia (sum of NH3 and NH4+) was observed.

Nettmann, E.; Bergmann, I.; Pramschufer, S.; Mundt, K.; Plogsties, V.; Herrmann, C.; Klocke, M.

2010-01-01

90

Granule development and performance in sucrose fed anaerobic baffled reactors.  

PubMed

Two 90 L anaerobic baffled reactors were used to study the granulation of sludge and the effect of the organic loading rate and NaHCO3/COD ratios on reactor performance. Furthermore, it was determined whether an anaerobic baffled reactor would promote phase separation and if additive of bentonite or granular active carbon was capable of enhancing granule formation. In order to minimize feed variations, and have a totally biodegradable substrate, a synthetic sucrose substrate was used. Granulation was achieved in both reactors within 75 days. However, the granules from the granular active carbon amended reactor appeared earlier and were larger and more compact. The reactors were maintained at a hydraulic retention time of 20 h during performance study stage. The results showed that when organic loading rate were changed from 2.15 to 6.29 kg COD m(-3)day(-1), chemical oxygen demand (COD) removal was not decreased (91-93%), but a slight increase in effluent COD was observed. It was found that the COD removals were generally good (87-92%) and had not obviously change with the decreasing NaHCO3/COD ratios. From the bacterial distribution and the concentration of volatile fatty acids in four compartments, it was concluded that a separation of phases occurred within the anaerobic baffled reactors. PMID:16256235

She, Zonglian; Zheng, Xilai; Yang, Bairen; Jin, Chunji; Gao, Mengchun

2005-10-26

91

Biogas: Integrated Systems, Diffusion Programs, Biogas for Motorized Systems.  

National Technical Information Service (NTIS)

Eleven communications concerning biogas technology and utilization are presented in this document. Some biogas digesters are described together with precisions on the problems and difficulties encountered during construction or utilization (mainly the pro...

F. Varagnat

1984-01-01

92

Improvement in fusion reactor performance due to ion channeling  

SciTech Connect

Ion channeling is a recent idea for improving the performance of fusion reactors by increasing the fraction of the fusion power deposited in the ions. In this paper the authors assess the effect of ion channeling on D-T and D-{sup 3}He reactors. The figures of merit used are the fusion power density and the cost of electricity. It is seen that significant ion channeling can lead to about a 50-65% increase in the fusion power density. For the Apollo D-{sup 3}He reactor concept the reduction in the cost of electricity can be as large as 30%.

Emmert, G.A.; El-Guebaly, L.A.; Kulcinski, G.L.; Santarius, J.F.; Sviatoslavsky, I.N. [Univ. of Wisconsin, Madison, WI (United States); Meade, D.M. [Princeton Plasma Physics Lab., NJ (United States)

1994-11-01

93

Trace compounds of biogas from different biogas production plants  

Microsoft Academic Search

Biogas composition and variation in three different biogas production plants were studied to provide information pertaining to its potential use as biofuel. Methane, carbon dioxide, oxygen, nitrogen, volatile organic compounds (VOCs) and sulphur compounds were measured in samples of biogases from a landfill, sewage treatment plant sludge digester and farm biogas plant. Methane content ranged from 48% to 65%, carbon

S. Rasi; A. Veijanen; J. Rintala

2007-01-01

94

Effect of reactor internal properties on the performance of a flow reversal catalytic reactor for methane combustion  

Microsoft Academic Search

This paper describes the use of a flow reversal reactor for the destruction of lean emissions of methane with ambient temperature feed. The reactor consisted of two parallel sections, each containing a packed bed reactor and inert sections to act as heat traps. In this paper, the effect on reactor performance of the inert properties is illustrated. Three different inert

A. Kushwaha; M. Poirier; H. Sapoundjiev; R. E. Hayes

2004-01-01

95

Horse dung waste utilization as a household energy resource and estimation of biogas production  

NASA Astrophysics Data System (ADS)

Horses are still used as traditional transportation in Soreang, West Java. About 6-7 horses can produce 25-30 kg of dung every day. Horse dung can produce biogas that can be used as an energy resource. A biogas reactor with capacity of 4 m3 has been built in Soreang. The reactor is filled with a mixture of 50 kg of horse dung and 100 liters of water every two days. This research was conducted to observe the quality of biogas produced from the reactor and to estimate the volume of biogas produced per day. The observation of daily biogas production conducted in 22 days. Laboratory tests showed that the composition of gases contained in the produced biogas consists of 56.53% of CH4, 26.98% of CO2, 12.35% of N2, 4.13% of O2, and 0.007% of H2. Daily biogas production data indicate a stationary trend. A moving average time series model is used to model the data. Using the model, it is estimated that the reactor can produce 0.240112 m3 of biogas per day, which is sufficient to meet the energy needs of a household.

Umbara, Rian F.; Sumaryatie, Erni D.; Kirom, M. R.; Iskandar, Reza F.

2013-09-01

96

Biogas energy technology in Sudan  

Microsoft Academic Search

Biogas from biomass appears to have potential as an alternative energy in Sudan, which is potentially rich in biomass resources. This is an overview of some salient points and perspectives of biogas technology in Sudan. The current literature is reviewed regarding the ecological, social, cultural and economic impacts of biogas technology. Sudan is blessed with abundant solar, wind, hydro, and

A. M. Omer; Y. Fadalla

2003-01-01

97

Performance and safety parameters for the high flux isotope reactor  

SciTech Connect

A Monte Carlo depletion model for the High Flux Isotope Reactor (HFIR) Cycle 400 and its use in calculating parameters of relevance to the reactor performance and safety during the reactor cycle are presented in this paper. This depletion model was developed to serve as a reference for the design of a low-enriched uranium (LEU) fuel for an ongoing study to convert HFIR from high-enriched uranium (HEU) to LEU fuel; both HEU and LEU depletion models use the same methodology and ENDF/B-VII nuclear data as discussed in this paper. The calculated HFIR Cycle 400 parameters, which are compared with measurement data from critical experiments performed at HFIR, data included in the HFIR Safety Analysis Report (SAR), or data reported by previous calculations, provide a basis for verification or updating of the corresponding SAR data. (authors)

Ilas, G. [Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831-6172 (United States); Primm III, T. [Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831-6172 (United States); Primm Consulting, LLC, 945 Laurel Hill Road, Knoxville, TN 37923 (United States)

2012-07-01

98

Modern control technology for improved nuclear reactor performance  

SciTech Connect

One of the main complaints leveled at reactor control systems by utility spokesmen is complexity. One only has to look inside a power reactor control room to appreciate this viewpoint. The high reliability and versatility of modern microprocessors makes possible distributed control systems with only performance data and abnormal conditions being relayed to the control room. In a sense, this emulates the human-body control system where routine repetitive actions are handled in an involuntary manner. The significance of expert systems to the nuclear reactor control and safety systems is their ability to capture human and other expertise and make it available, upon demand, and under almost all circumstances. Thus, human problem-solving skills acquired by the learning process over a long period of time can be captured and employed with the reliability inherent in computers. This is especially important in nuclear plants when human operators are burdened by stress and emotional factors that have a dramatic effect on performance level.

Oakes, L.C.

1986-12-01

99

Commercialized fast reactor cycle systems and reactor core performance of the promising fast reactors  

Microsoft Academic Search

The Feasibility Study on Commercialized Fast Reactor (FR) Cycle Systems is under progress in order to propose prominent FR cycle systems that will respond to the diverse needs of society in the future. The design studies on various FR system concepts have been achieved and then the evaluations of potential to achieve the development targets have been also carried out.

Shoji Kotake; Yoshihiko Sakamoto; Yutaka Sagayama

2005-01-01

100

Liquid membrane purification of biogas  

SciTech Connect

Conventional gas purification technologies are highly energy intensive. They are not suitable for economic removal of CO{sub 2} from methane obtained in biogas due to the small scale of gas production. Membrane separation techniques on the other hand are ideally suited for low gas production rate applications due to their modular nature. Although liquid membranes possess a high species permeability and selectivity, they have not been used for industrial applications due to the problems of membrane stability, membrane flooding and poor operational flexibility, etc. A new hollow-fiber-contained liquid membrane (HFCLM) technique has been developed recently. This technique overcomes the shortcomings of the traditional immobilized liquid membrane technology. A new technique uses two sets of hydrophobic, microporous hollow fine fibers, packed tightly in a permeator shell. The inter-fiber space is filled with an aqueous liquid acting as the membrane. The feed gas mixture is separated by selective permeation of a species through the liquid from one fiber set to the other. The second fiber set carries a sweep stream, gas or liquid, or simply the permeated gas stream. The objectives (which were met) of the present investigation were as follows. To study the selective removal of CO{sub 2} from a model biogas mixture containing 40% CO{sub 2} (the rest being N{sub 2} or CH{sub 4}) using a HFCLM permeator under various operating modes that include sweep gas, sweep liquid, vacuum and conventional permeation; to develop a mathematical model for each mode of operation; to build a large-scale purification loop and large-scale permeators for model biogas separation and to show stable performance over a period of one month.

Majumdar, S.; Guha, A.K.; Lee, Y.T.; Papadopoulos, T.; Khare, S. (Stevens Inst. of Tech., Hoboken, NJ (United States). Dept. of Chemistry and Chemical Engineering)

1991-03-01

101

Biogas purification processes  

Microsoft Academic Search

A review on the processes that have been used or are promising for the removal of COâ, HâS, and water vapor from biogas. The process conditions and flow schemes for 16 processes are given. The basic physical mechanisms that are involved in the processes are discussed and include physical absorption into a liquid (dissolution), chemical absorption into a liquid, physical

J. C. Glaub; L. F. Diaz

1981-01-01

102

Cooperative Biogas Production.  

National Technical Information Service (NTIS)

A study of the feasibility of a cooperative biogas production in France is presented. The objectives were to minimize the constraints for the farmers, to mechanize in a simple manner the supply of agricultural wastes to the facility, to recover the proces...

F. Cayrol

1983-01-01

103

Turkey's Biogas Energy Potential  

Microsoft Academic Search

As in the rest of the world, in Turkey it is necessary to utilize the renewable energy sources to make up for the increasing energy deficit. As an alternative to these energy sources, the use of biogas seems possible. Even when it is considered only with regards to the animal husbandry sector, the majority of the manure obtained is a

N. Kizilaslan; H. Kizilaslan

2007-01-01

104

Computational Neutronics Methods and Transmutation Performance Analyses for Fast Reactors  

SciTech Connect

The once-through fuel cycle strategy in the United States for the past six decades has resulted in an accumulation of Light Water Reactor (LWR) Spent Nuclear Fuel (SNF). This SNF contains considerable amounts of transuranic (TRU) elements that limit the volumetric capacity of the current planned repository strategy. A possible way of maximizing the volumetric utilization of the repository is to separate the TRU from the LWR SNF through a process such as UREX+1a, and convert it into fuel for a fast-spectrum Advanced Burner Reactor (ABR). The key advantage in this scenario is the assumption that recycling of TRU in the ABR (through pyroprocessing or some other approach), along with a low capture-to-fission probability in the fast reactor’s high-energy neutron spectrum, can effectively decrease the decay heat and toxicity of the waste being sent to the repository. The decay heat and toxicity reduction can thus minimize the need for multiple repositories. This report summarizes the work performed by the fuel cycle analysis group at the Idaho National Laboratory (INL) to establish the specific technical capability for performing fast reactor fuel cycle analysis and its application to a high-priority ABR concept. The high-priority ABR conceptual design selected is a metallic-fueled, 1000 MWth SuperPRISM (S-PRISM)-based ABR with a conversion ratio of 0.5. Results from the analysis showed excellent agreement with reference values. The independent model was subsequently used to study the effects of excluding curium from the transuranic (TRU) external feed coming from the LWR SNF and recycling the curium produced by the fast reactor itself through pyroprocessing. Current studies to be published this year focus on analyzing the effects of different separation strategies as well as heterogeneous TRU target systems.

R. Ferrer; M. Asgari; S. Bays; B. Forget

2007-03-01

105

Biogas electric power generation: 25 kW or greater  

SciTech Connect

A biogas cogeneration system consists basically of: an anaerobic digester to produce the gas, a prime mover which burns the gas and makes power, and recovery devices which capture engine waste heat. Guidance is given through the exercise of determining whether biogas cogeneration is worthwhile. Design, construction, and operation are covered in general. Theoretical and practical background on biogas cogeneration are given, and directions for collecting site data and a method for performing a preliminary economic analysis for a given operation are given. (LEW)

Not Available

1981-06-01

106

Retrospective Search on Economics of Biogas Production.  

National Technical Information Service (NTIS)

This literature survey covers the period 1969 to date and is concerned with the economics of biogas production. Among the aspects dealt with are: biogas from agricultural, industrial and municipal wastes; and biogas in developing countries. (ERA citation ...

1983-01-01

107

Pilot Plant for Extraction of Biogas. Technical Description.  

National Technical Information Service (NTIS)

The report describes a research biogas plant built in 1979-1980 in Rogaland (Norway). The plant was built closely connected to a dairy barn. The reactor is made of concrete, and is divided into 2 equal parts by means of a vertical wall. Each part contain ...

O. Tjernshaugen J. Soerreime J. O. Gjervan I. F. Hansen

1983-01-01

108

Operation and performance of the Supercritical Fluids Reactor (SFR)  

SciTech Connect

The Supercritical Fluids Reactor (SFR) at Sandia National Laboratories, CA has been developed to examine and solve engineering, process, and fundamental chemistry issues regarding the development of supercritical water oxidation (SCWO). This report details the experimental apparatus, procedures, analytical methods used in these experiments, and performance characteristics of the reactor. The apparatus consists of pressurization, feed, preheat, reactor, cool down, and separation subsystems with ancillary control and data acquisition hardware and software. Its operating range is from 375 - 650{degrees} at 3250 - 6300 psi with resident times from 0.09 to 250 seconds. Procedures required for experimental operations are described. They include maintenance procedures conducted between experiments, optical alignment for acquisition of spectroscopic data, setup of the experiment, reactor start up, experimental operations, and shutdown of apparatus. Analytical methods used are Total Organic Carbon analysis, Gas Chromatography, ion probes, pH probes, turbidity measurements and in situ Raman spectroscopy. Experiments conducted that verify the accuracy of measurement and sampling methods are described.

Hanush, R.G.; Rice, S.F.; Hunter, T.B.; Aiken, J.D.

1995-11-01

109

Performance of Liquid Metals in Natural Circulation Cooled Nuclear Reactors  

SciTech Connect

The inherent safety capability of natural circulation makes reactor design more reliable. Additionally, the construction and operation of a nuclear power plant with natural circulation in the primary cooling circuit is an interesting alternative for nuclear plant designers, due to their lower operational and investment costs obtained by simplifying systems and controls. This paper deals with the feasibility of application of natural circulation in the primary cooling circuit of a liquid metal fast reactor. The methodology employed is a non-dimensional analysis, which describes the relationship between the physical properties and system variables. The performance criterion is bounded by a safety argument, referring to the maximum cladding temperature allowed during operation. The study considers several coolants, which can play a part in reactor cooling systems, such as lead, lead-bismuth and sodium. Bismuth and gallium are included in this analysis, in order to extend the range of properties for reference purposes. The results present a characterization of natural circulation flow in a reactor and compare the cooling capabilities from different liquid metals coolants. (authors)

Ceballos, Carlos; Lathouwers, Danny; Verkooijen, Adrian [Interfacultair Reactor Instituut, Technische Universiteit Delft, Mekelweg 15, Delft (Netherlands)

2004-07-01

110

Understanding biogas generation. Technical paper  

SciTech Connect

Biogas is a by-product of the biological breakdown - under oxygen-free conditions - of organic wastes such as plants, crop residues, wood and bark residues, and human and animal manure. Biogas generators or digesters yield two products: the biogas itself, and a semi-solid by-product called effluent or sludge. Biogas systems are most popular for their ability to produce fuel from products that might otherwise be wasted-crop residues, manures, etc. The fuel is a flammable gas suitable for cooking, lighting, and fueling combustion engines. The digested waste--sludge--is a high quality ferterlizer.

Mattocks, R.

1984-01-01

111

Biogas purification processes  

SciTech Connect

A review on the processes that have been used or are promising for the removal of CO/sub 2/, H/sub 2/S, and water vapor from biogas. The process conditions and flow schemes for 16 processes are given. The basic physical mechanisms that are involved in the processes are discussed and include physical absorption into a liquid (dissolution), chemical absorption into a liquid, physical absorption onto a solid, chemical conversion to another compound, membrane separation, and condensation.

Glaub, J.C.; Diaz, L.F.

1981-01-01

112

An Implicit Solution Framework for Reactor Fuel Performance Simulation  

SciTech Connect

The simulation of nuclear reactor fuel performance involves complex thermomechanical processes between fuel pellets, made of fissile material, and the protective cladding that surrounds the pellets. An important design goal for a fuel is to maximize the life of the cladding thereby allowing the fuel to remain in the reactor for a longer period of time to achieve higher degrees of burnup. This presentation presents an initial approach for modeling the thermomechanical response of reactor fuel, and details of the solution method employed within INL's fuel performance code, BISON. The code employs advanced methods for solving coupled partial differential equation systems that describe multidimensional fuel thermomechanics, heat generation, and oxygen transport within the fuel. This discussion explores the effectiveness of a JFNK-based solution of a problem involving three dimensional fully coupled, nonlinear transient heat conduction and that includes pellet displacement and oxygen diffusion effects. These equations are closed using empirical data that is a function of temperature, density, and oxygen hyperstoichiometry. The method appears quite effective for the fuel pellet / cladding configurations examined, with excellent nonlinear convergence properties exhibited on the combined system. In closing, fully coupled solutions of three dimensional thermomechanics coupled with oxygen diffusion appear quite attractive using the JFNK approach described here, at least for configurations similar to those examined in this report.

Glen Hansen; Chris Newman; Derek Gaston; Cody Permann

2009-08-01

113

The design and performance of the research reactor fuel counter  

SciTech Connect

This paper describes the design features, hardware specifications, and performance characteristics of the Research Reactor Fuel Counter (RRFC) System. The system is an active mode neutron coincidence counter intended to assay material test reactor fuel assemblies under water. The RRFC contains 12 {sup 3}He tubes, each with its own preamplifier, and a single ion chamber. The neutron counting electronics are based on the Los Alamos Portable Shift Register (PSR) and the gamma readout is a manual-range pico-ammeter of Los Alamos design. The RRFC is connected to the surface by a 20-m-long cable bundle. The PSR is controlled by a portable IBM computer running a modified version of the Los Alamos neutron coincidence counting code also called RRFC. There is a manual that describes the RRFC software.

Abhold, M.E.; Hsue, S.T.; Menlove, H.O.; Walton, G.; Holt, S.

1996-09-01

114

LQG\\/LTR robust control of nuclear reactors with improved temperature performance  

Microsoft Academic Search

The authors present the design of a robust controller using the linear quadratic Gaussian with loop transfer recovery (LQG\\/LTR) for nuclear reactors with the objective of maintaining a desirable performance for reactor fuel temperature and the temperature of the coolant leaving the reactor for a wide range of reactor powers. The results obtained are compared to those for an observer-based

Adel Ben-Abdennour; Robert M. Edwards; Kwang Y. Lee

1992-01-01

115

Biogas production from olive pomace  

Microsoft Academic Search

Biogas production from a slurry obtained by mixing finely ground olive pomace in water was investigated using anaerobic digesters of 1-l working volume at 37°C. A start-up culture was obtained from a local landfill area and was adopted to the slurry within 10 days at this temperature. The biogas generation rates were determined by varying the total solids (TS) concentration

Ali R Tekin; A. Co?kun Dalg?ç

2000-01-01

116

Shell structures for biogas plants  

SciTech Connect

The shell structures designed for biogas plants of the fixed-dome type by the Bremen Overseas Research and Development Association are described. Biogas digesters of the design described have been successfully tested in Rwanda and India without structural or contractural problems.

Sasse, L.

1982-01-01

117

Enzymatic pre-treatment of cellulose rich biomasses for use in the biogas process  

Microsoft Academic Search

ABSTRACT Enzymatic pre-treatment of cellulose rich biomasses for use in the biogas process Erik Stenströmer Moglia An experimental study was performed in order to investigate the effect of an enzymatic pre-treatment step for the biogas production potential from cellulose rich material. The enzymes,used for the pre-treatments were a mix of cellulases and hemicellulases. The biogas production was determined by an

Erik Stenströmer Moglia

118

Screening of novel plants for biogas production in northern conditions.  

PubMed

The objective of this study was to screen nine annual or perennial novel plants for biogas production cultivated in years 2007-2010 in Finland. The most promising novel plants for biogas production were found to be brown knapweed, giant goldenrod and Japanese millet producing 14-27 t total solids/ha and 4000-6100 Nm(3)CH4/ha. The specific methane yields of all studied plants varied from 170 to 381 Nm(3)CH4/t volatile solids (VS), depending on harvest time and plant species. Co-digestion of brown knapweed with cow manure in continuously stirred tank reactor was investigated and the highest methane yield was 254 NL CH4/kg VS, when the share of brown knapweed was 50% in the feed VS (organic loading rate (OLR) 2 kg VS/m(3)/d). The cultivation managements and sustainability of novel plants for biogas production have to be investigated. PMID:23669072

Seppälä, Mari; Laine, Antti; Rintala, Jukka

2013-04-13

119

Pretreatment of chicken feather waste for improved biogas production.  

PubMed

This study deals with the utilization of chicken feather waste as a substrate for anaerobic digestion and improving biogas production by degradation of the compact structure of the feather keratin. In order to increase the digestibility of the feather, different pretreatments were investigated, including thermal pretreatment at 120 °C for 10 min, enzymatic hydrolysis with an alkaline endopeptidase [0.53-2.66 mL/g volatile solids (VS) feathers] for 0, 2, or 24 h at 55 °C, as well as a combination of these pretreatments. The effects of the treatments were then evaluated by anaerobic batch digestion assays at 55 °C. The enzymatic pretreatment increased the methane yield to 0.40 Nm(3)/kg VS(added), which is 122 % improvement compared to the yield of the untreated feathers. The other treatment conditions were less effective, increasing the methane yield by 11-50 %. The long-term effects of anaerobic digestion of feathers were examined by co-digestion of the feather with organic fraction of municipal solid waste performed with and without the addition of enzyme. When enzyme was added together with the feed, CH(4) yield of 0.485 Nm(3)/kg VS(-1) d(-1) was achieved together with a stable reactor performance, while in the control reactor, a decrease in methane production, together with accumulation of undegraded feather, was observed. PMID:23359010

Forgács, Gergely; Lundin, Magnus; Taherzadeh, Mohammad J; Sárvári Horváth, Ilona

2013-01-29

120

Janata biogas technology and fodder production  

Microsoft Academic Search

An effective bio-gas program leads to efficient use of cow dung for gas recovery and partial supplement to plant nutrient requirements. Bio-gas program leads to improvement in rural living including rural sanitation. The Janata biogas plant designed by the State Planning Institute, Lucknow, based on biogas technology, has proved to be efficient and economical. This book contains the various papers

Neelakantan

1981-01-01

121

Biogas: Production and utilization  

NASA Astrophysics Data System (ADS)

Among the aspects of biogas production and utilization covered are: (1) the microbiology and biochemistry of the acid and methane production stages in the anaerobic process; (2) factors affecting the process, such as temperature, acidity and alkalinity, nutrients, and cations; (3) denitrification processes and systems; and (4) the process kinetics of suspended growth systems, packed columns, and fluidized beds. Also considered are such issues in the application of this technology as the digestion of municipal treatment plant sludges, animal wastes, food processing wastes and energy crops. Attention is in addition given to anaerobic digester design, offgas measurement of anaerobic digesters, and sludge treatment through soil conditioning and composting.

Price, E. C.; Cheremisinoff, P. N.

122

Safety performance of the 4S reactor on the ATWS events – statistical estimation of uncertainty  

Microsoft Academic Search

4S reactor is a sodium-cooled fast reactor developed as a small-decentralized power supply. The name of “4S” in this reactor stands for Super-Safe, Small and Simple, and they show representative features of the reactor.The purpose of the present work is to evaluate quantitatively the super-safety of 4S reactor, and the safety performance is analyzed with ARGO-3, which is a plant

Hideki Horie; Kazumi Miyagi; Katsuhiko Nakahara; Hisato Matsumiya

2008-01-01

123

Coupling of sequencing batch reactor and mesh filtration: Operational parameters and wastewater treatment performance  

Microsoft Academic Search

Wastewater treatment performance of the combined process of sequencing batch reactor (SBR) and mesh filtration bio-reactor was investigated with a synthetic wastewater. In this system, the filtration was performed only by the water level difference between the reactor and the effluent port, with the help of a sludge layer which accumulated on the mesh filter.A half volume of the mixed

Yoshiaki Kiso; Yong-Jun Jung; Min-Soo Park; Wenhui Wang; Masahiro Shimase; Toshiro Yamada; Kyung-Sok Min

2005-01-01

124

Impact of nickel and cobalt on biogas production and process stability during semi-continuous anaerobic fermentation of a model substrate for maize silage.  

PubMed

The importance of nickel and cobalt on anaerobic degradation of a defined model substrate for maize was demonstrated. Five semi-continuous reactors were operated for 250 days at 35 °C and a well-defined trace metal solution was added to all reactors. Two reactors each were limited regarding the concentration of Ni(2+) and Co(2+), respectively, for certain time intervals. The required nickel concentration was depending on the organic loading rates (OLR) while, for example, above 2.6 g ODM L(-1) d(-1) nickel concentrations below 0.06 mg kg(-1) FM in the process significantly decreased biogas production by up to 25% compared to a control reactor containing 0.8 mg Ni(2+) kg(-1) FM. Similarly, limitation of cobalt to 0.02 mg kg(-1) FM decreased biogas production by about 10%. Limitations of nickel as well as cobalt lead to process instability. However, after gradual addition of nickel till 0.6 mg and cobalt till 0.05 mg kg(-1) FM the OLR was again increased to 4.3 g ODM L(-1) d(-1) while process stability was recovered and a fast metabolisation of acetic and propionic acid was detected. An increase of nickel to 0.88 mg kg(-1) FM did not enhance biogas performance. Furthermore, the increase of cobalt from 0.05 mg kg(-1) FM up to 0.07 mg kg(-1) FM did not exhibit a change in anaerobic fermentation and biogas production. PMID:20875911

Pobeheim, Herbert; Munk, Bernhard; Lindorfer, Harald; Guebitz, Georg M

2010-09-15

125

Performance of the PRISM (power reactor - innovative, small module) reactor's passive decay heat removal system  

Microsoft Academic Search

The PRISM (power reactor - innovative, small module) modular reactor concept has a totally passive decay heat removal system referred to as the reactor vessel auxiliary cooling system (RVACS) that rejects heat from the reactor by radiation and natural convection of air. The system is inherently reliable and is not subject to the failure modes commonly associated with active cooling

P. M. Magee; A. Hunsbedt

1989-01-01

126

Monitoring and control of the biogas process based on propionate concentration using online VFA measurement  

Microsoft Academic Search

Simple logic control algorithms were tested for automatic control of a lab-scale CSTR manure digester. Using an online VFA monitoring system, propionate concentration in the reactor was used as parameter for control of the biogas process. The propionate concentration was kept below a threshold of 10 mM by manipulating the feed flow. Other online parameters such as pH, biogas production,

Kanokwan Boe; Irini Angelidaki; Jean-Philippe Steyer

2008-01-01

127

Regulation and optimization of the biogas process: Propionate as a key parameter  

Microsoft Academic Search

The use of volatile fatty acids (VFA) as process indicators in biogas reactors treating manure together with industrial waste was studied. At a full-scale biogas plant, an online VFA sensor was installed in order to study VFA dynamics during stable and unstable operation. During stable operation acetate increased significantly during the feeding periods from a level of 2–4 to 12–17mM,

Henrik Bangsø Nielsen; Hinrich Uellendahl; Birgitte Kiær Ahring

2007-01-01

128

Graphite first wall thermal performance in ICF reactor  

NASA Astrophysics Data System (ADS)

Graphite has been considered as a candidate material for the first wall in ICF reactors. This paper shows the thermal performance of the graphite first wall (GFW) in the 0.25 ?m laser driven materials test reactor SIRIUS-M. The first wall temperature response due to the X-rays, reflected laser light, and ions that emanate from the 13.4 MJ yield target was calculated for dry GFWs which were either unprotected or gas protected. Evaporation rates and thermal stresses were calculated and minimum radii were chosen for both cases. It was found that the reflected laser light from the target produces the highest temperature rise in the gas protected GFW. If 10% of the laser light is reflected from the target and the reflectivity of graphite is 50%, the maximum thermal stress in the GFW is about 90% of the compressive strength for a 2 m radius cavity. Therefore, the viability of the first wall design depends critically on the laser light reflected from the target. the graphite reflectivity and the strength of the graphite.

Attaya, H.; Lovell, E.; Engelstad, R.; Peterson, R.; Liang, J.; Abdel-Khalik, S.; Moses, G.; Kulcinski, G.

1986-11-01

129

Titer-plate formatted continuous flow thermal reactors: Design and performance of a nanoliter reactor.  

PubMed

Arrays of continuous flow thermal reactors were designed, configured, and fabricated in a 96-device (12 × 8) titer-plate format with overall dimensions of 120 mm × 96 mm, with each reactor confined to a 8 mm × 8 mm footprint. To demonstrate the potential, individual 20-cycle (740 nL) and 25-cycle (990 nL) reactors were used to perform the continuous flow polymerase chain reaction (CFPCR) for amplification of DNA fragments of different lengths. Since thermal isolation of the required temperature zones was essential for optimal biochemical reactions, three finite element models, executed with ANSYS (v. 11.0, Canonsburg, PA), were used to characterize the thermal performance and guide system design: (1) a single device to determine the dimensions of the thermal management structures; (2) a single CFPCR device within an 8 mm × 8 mm area to evaluate the integrity of the thermostatic zones; and (3) a single, straight microchannel representing a single loop of the spiral CFPCR device, accounting for all of the heat transfer modes, to determine whether the PCR cocktail was exposed to the proper temperature cycling. In prior work on larger footprint devices, simple grooves between temperature zones provided sufficient thermal resistance between zones. For the small footprint reactor array, 0.4 mm wide and 1.2 mm high fins were necessary within the groove to cool the PCR cocktail efficiently, with a temperature gradient of 15.8°C/mm, as it flowed from the denaturation zone to the renaturation zone. With temperature tolerance bands of ±2°C defined about the nominal temperatures, more than 72.5% of the microchannel length was located within the desired temperature bands. The residence time of the PCR cocktail in each temperature zone decreased and the transition times between zones increased at higher PCR cocktail flow velocities, leading to less time for the amplification reactions. Experiments demonstrated the performance of the CFPCR devices as a function of flow velocity, fragment length, and copy number. A 99 bp DNA fragment was successfully amplified at flow velocities from 1 mm/s to 3 mm/s, requiring from 8.16 minutes for 20 cycles (24.48 s/cycle) to 2.72 minutes for 20 cycles (8.16 s/cycle), respectively. Yield compared to the same amplification sequence performed using a bench top thermal cycler decreased nonlinearly from 73% (at 1 mm/s) to 13% (at 3 mm/s) with shorter residence time at the optimal temperatures for the reactions due to increased flow rate primarily responsible. Six different DNA fragments with lengths between 99 bp and 997 bp were successfully amplified at 1 mm/s. Repeatable, successful amplification of a 99 bp fragment was achieved with a minimum of 8000 copies of the DNA template. This is the first demonstration and characterization of continuous flow thermal reactors within the 8 mm × 8 mm footprint of a 96-well micro-titer plate and is the smallest continuous flow PCR to date. PMID:20871807

Chen, Pin-Chuan; Park, Daniel S; You, Byoung-Hee; Kim, Namwon; Park, Taehyun; Soper, Steven A; Nikitopoulos, Dimitris E; Murphy, Michael C

2010-08-01

130

A Comparative Study between the Newly Improved and Chinese National Standard Biogas Digesters in a Semi-arid Region of Northwest China  

Microsoft Academic Search

China has intensified the extension of family-sized biogas digesters with the Chinese National Standard in the 1990s. However, such biogas digesters have not performed well. In order to improve the current National Standard biogas digesters, the authors have designed, tested, and demonstrated 200 improved biogas digesters in a semi-arid region of China over the past 7 years and conducted a

W. Ding; X. Mi; Y. Xian; Y. Wei; H. Niu

2012-01-01

131

Liquid Membrane Purification of Biogas.  

National Technical Information Service (NTIS)

Conventional gas purification technologies are highly energy-intensive and generally unsuited for small-scale biogas applications. Membrane separation techniques may be appropriate for low-volume carbon dioxide/methane gas systems. Polymeric membranes as ...

S. Majumdar A. K. Guha Y. T. Lee T. Papadopoulos S . Khare

1991-01-01

132

Trace element requirements of agricultural biogas digesters during biological conversion of renewable biomass to methane  

Microsoft Academic Search

The availability of trace metals as micro-nutrients plays a very significant role on the performance and stability of agricultural biogas digesters, which are operated with energy crops, animal excreta, crop residues, organic fraction of municipal solid wastes or any other type of organic waste. The unavailability of these elements in biogas digesters is probably the first reason of poor process

B. Demirel; P. Scherer

2011-01-01

133

Biogas production enhancement by soya sludge amendment in cattle dung digesters  

Microsoft Academic Search

Biogas energy production from cattle dung is an economically feasible and eco-friendly in nature. But dependence only on cattle dung is a limiting factor. Rich nitrogen containing substrate addition to extra carbohydrate digester like cattle dung could improve the biogas production. Detailed performance of the digesters at different ratios of cattle dung and soya sludge has been discussed in this

Shanta Satyanarayan; Ramakant; Shivayogi

2010-01-01

134

Effect of temperature and active biogas process on passive separation of digested manure  

Microsoft Academic Search

The objective of the study was to identify the optimum time interval for effluent removal after temporarily stopping stirring in otherwise continuously stirred tank reactors. Influence of temperature (10 and 55°C) and active biogas process on passive separation of digested manure, where no outside mechanical or chemical action was used, within the reactor was studied in three vertical settling columns

P. Kaparaju; I. Angelidaki

2008-01-01

135

Core performance of fast reactors for actinide recycling using metal, nitride, and oxide fuels  

Microsoft Academic Search

Core performance analyses are conducted for fast reactors that accept and recycle the plutonium and minor actinides (MAs) recovered from light water reactor (LWR) spent fuel, together with the plutonium and MAs from the fast reactors` own production. Metal, nitride, and oxide are the fuel materials used to compare the neutronic and safety parameters and to discuss acceptable minor actinide

Takeshi Yokoo; Akihiro Sasahara; Tadashi Inoue; Jungmin Kang; Atsuyuki Suzuki

1996-01-01

136

Performance of immobilized glucoamylase in a magnetically stabilized fluidized bed reactor (MSFBR)  

Microsoft Academic Search

Glucoamylase (EC 3.2.1.3. from Aspergillus niger) was immobilized onto the magnetic polystyrene particles including active groups. These particles were used in a magnetically stabilized fluidized bed reactor, and performance of this reactor was investigated. Magnetically stabilized fluidized bed reactor was made of a jacketed glass column and a coaxial selenoid covering the whole column as the magnetic field source. An

Tahsin Bahar; Serdar S. Çelebi

2000-01-01

137

Application of neural network for simulation of upflow anaerobic sludge blanket (UASB) reactor performance.  

PubMed

Up-flow anaerobic sludge blanket (UASB) reactors are being used with increasing regularity all over the world, especially in India, for a variety of wastewater treatment operations. Consequently, there is a need to develop methodologies enabling one to determine UASB reactor performance, not only for designing more efficient UASB reactors but also for predicting the performance of existing reactors under various conditions of influent wastewater flows and characteristics. This work explores the feasibility of application of an artificial neural network-based model for simulating the performance of an existing UASB reactor. Accordingly, a neural network model was designed and trained to predict the steady-state performance of a UASB reactor treating high-strength (unrefined sugar based) wastewater. The model inputs were organic loading rate, hydraulic retention time, and influent bicarbonate alkalinity. The output variables were one or more of the following, effluent substrate concentration (Se), reactor bicarbonate alkalinity, reactor pH, reactor volatile fatty acid concentration, average gas production rate, and percent methane content of the gas. Training of the neural network model was achieved using a large amount of experimentally obtained reactor performance data from the reactor mentioned above as the training set. Training was followed by validation using independent sets of performance data obtained from the same UASB reactor. Subsequently, simulations were performed using the validated neural network model to determine the impact of changes in parameters like influent chemical oxygen demand (COD) concentration and hydraulic retention time on the reactor performance. Simulation results thus obtained were carefully analyzed based on qualitative understanding of UASB process and were found to provide important insights into key variables that were responsible for influencing the working of the UASB reactor under varying input conditions. PMID:11835141

Sinha, Sucheta; Bose, Purnendu; Jawed, Mohammed; John, Siby; Tare, Vinod

2002-03-30

138

Quick start-up of EGSB reactor treating fresh leachate of municipal solid waste  

Microsoft Academic Search

An expanded granular sludge bed (EGSB) reactor inoculated with anaerobic granular sludge was started up with its COD removal\\u000a performance, self-balancing of pH, biogas production rate and characteristics of the granular sludge during the start-up period\\u000a being investigated. The results indicated that the EGSB reactor can be started up successfully in 27 d by increasing the organic\\u000a loading rate rapidly.

Jian-yong Liu; Hua-dan Bian; Ya-li Cao; Jiang-ping Zhong; Jun Hu; Qiang Liu; Guang-ren Qian; Feng Liu; Jun Tai

2011-01-01

139

Operating experience feedback report: Human performance in operating events. Volume 8, Commercial power reactors  

Microsoft Academic Search

This report describes the results of a Nuclear Regulatory Commission (NRC) program begun in 1990 to conduct onsite, indepth studies of human performance that affected reactor safety during selected power reactor events. The purpose of the program is to identify the factors that have contributed to good operator performance during events, as well as the factors that hindered performance, and

J. V. Kauffman; G. F. Lanik; R. A. Spence; E. A. Trager

1992-01-01

140

Serial CSTR digester configuration for improving biogas production from manure  

Microsoft Academic Search

A new configuration of manure digesters for improving biogas production has been investigated in laboratory scale. A single thermophilic continuous-flow stirred tank reactor (CSTR) operated with a hydraulic retention time (HRT) of 15 days was compared to a serial CSTR configuration with volume distribution ratio of 80\\/20 and 90\\/10, and total HRT of 15 days. The results showed that the

Kanokwan Boe; Irini Angelidaki

2009-01-01

141

Prism sodium-cooled reactor design and performance  

Microsoft Academic Search

The Power Reactor Inherently Safe Module (PRISM) program is being conducted at General Electric (GE) under U.S. Department of Energy sponsorship to develop a conceptual design for an advanced sodium-cooled liquid-metal reactor plant. The PRISM design emphasizes inherent safety, modular construction, and factory fabrication. A PRISM power plant includes a number of reactor modules, which will be fabricated in a

W. Kwant; P. M. Magee; M. R. Patel

1989-01-01

142

Biogas production from Jatropha curcas press-cake  

SciTech Connect

Seeds of the tropical plant Jatropha curcas (purge nut, physic nut) are used for the production of oil. Several methods for oil extraction have been developed. In all processes, about 50% of the weight of the seeds remain as a press cake containing mainly protein and carbohydrates. Investigations have shown that this residue contains toxic compounds and cannot be used as animal feed without further processing. Preliminary experiments have shown that the residue is a good substrate for biogas production. Biogas formation was studied using a semicontinous upflow anaerobic sludge blanket (UASB) reactor; a contact-process and an anaerobic filter each reactor having a total volume of 110 L. A maximum production rate of 3.5 m{sup 3} m{sup -3} d{sup -1} was obtained in the anaerobic filter with a loading rate of 13 kg COD m{sup -3} d{sup -1}. However, the UAS reactor and the contact-process were not suitable for using this substrate. When using an anaerobic filter with Jatropha curcas seed cake as a substrate, 76% of the COD was degraded and 1 kg degraded COD yielded 355 L of biogas containing 70% methane. 28 refs., 3 figs., 4 tabs.

Staubmann, R.; Guebitz, G.M.; Lafferty, R.M. [Graz Technical Univ. (Austria)] [and others

1997-12-31

143

The Evaluation of Reactor Performance by using Flibe and Flinabe Molten Salts in the APEX Hybrid Reactor  

Microsoft Academic Search

The modeling of APEX hybrid reactor, produced by using ARIES-RS hybrid reactor technology, has been performed by using the\\u000a MCNP-4B computer code and ENDF\\/B-V-VI nuclear data. Around the fusion chamber, molten salts Flibe (Li2BeF4) and Flinabe (LiNaBeF4) were used as cooling materials. APEX reactor was modeled in the torus form by adding nuclear materials of low significance\\u000a in the specified

Turgay Korkut; Aybaba Hançerlio?ullar?

144

Feasibility of Biogas Production on Farms.  

National Technical Information Service (NTIS)

An overview of biogas technology is presented. The following topics are discussed: the potentials and limitations of anaerobic digestion; on-site energy generation: relationship of demand to supply; economics of farm-scale biogas production; design consid...

W. J. Jewell B. A. Adams B. P. Eckstrom K. J. Fanfoni R. M. Kabrick

1982-01-01

145

Economic Aspects of Biogas Production in Agriculture.  

National Technical Information Service (NTIS)

The biogas technology is discussed under economic aspects. The dissertation has two main parts. The technical part, which is short and not very detailed, describes the biochemical fundamentals and process technology of biogas production. The economic part...

G. Frick

1983-01-01

146

Compressed Biogas at the Christchurch Drainage Board.  

National Technical Information Service (NTIS)

Describes the experience of the Christchurch Drainage Board in using biogas for fueling a part of its transport fleet. Documents the experience and demonstrates the benefits to other potential users of biogas.

1986-01-01

147

Biogasification of biowaste and sewage sludge--measurement of biogas quality.  

PubMed

Biogas quality, the presence of some trace components (siloxanes, sulfur compounds, volatile organic compounds, VOCs) in biogas, is in a decisive role when determining the biogas utilization and the purification requirements and equipments. In the present work, the effects of process changes related to reactor loading variations on the concentrations of selected trace compounds in biogas were studied. Source separated biowaste and sewage sludge were co-digested in a mesophilic pilot reactor (200 L) for four months during which the organic load was stepwise increased. The results showed that the process worked steadily up to the load of 8 kgVS m(-3)d(-1). Also the community composition of methanogenic archae stayed largely unaffected by the load increase, and was at all stages typical for a mesophilic biogasification process. Gaseous concentrations of siloxanes, hydrogen sulfide and most VOCs remained at a constant low level, showing no sensitivity to variations in the load and related process changes. However, the total siloxane concentration in the biogas was dependent on feed quality, and the detected concentrations require removal prior to use in turbines or fuel cells. Otherwise, after the removal of siloxanes, the biogas studied in this work is well applicable in various electricity production options, like in gas engines, turbines, microturbines and fuel cells. PMID:21295904

Kymäläinen, M; Lähde, K; Arnold, M; Kurola, J M; Romantschuk, M; Kautola, H

2011-02-05

148

Biogas in Cameroon  

SciTech Connect

The design and testing of 7 prototype biogas digesters in Cameroon are described. The 7 digesters designs are: a 2.6-m/sup 3/ rectangular horizontal fermentation chamber with a rectangular metal gas holder floating on the slurry; a 12-m/sup 3/ vertical-circular fermentation chamber with a separate pre-mixing tank and a circular metal gas dome floating on the slurry; a 9-m/sup 3/ horizontal fermentation chamber with a rectangular metal gas holder floating on the slurry; a 12-m/sup 3/ rectangular horizontal fermentation chamber with a rectangular metal gas holder over the entire chamber; a 9-m/sup 3/ horizontal rectangular fermentation chamber with a metal gas holder floating on the slurry and a 25-m long gas pipe; a 4-m/sup 3/ rectangular horizontal fermentation chamber with a metal gas holder floating on the slurry and a 18-m long gas pipe; and a 6.85-m/sup 3/ horizontal fermentation chamber with a metal gas holder floating on the slurry and a 20-m long gas pipe.

Wisenberg, R.

1982-01-01

149

Enhancement of Tokamak Fusion Test Reactor performance by lithium conditioning  

SciTech Connect

Wall conditioning in the Tokamak Fusion Test Reactor (TFTR) [K. M. McGuire {ital et} {ital al}., Phys. Plasmas {bold 2}, 2176 (1995)] by injection of lithium pellets into the plasma has resulted in large improvements in deuterium{endash}tritium fusion power production (up to 10.7 MW), the Lawson triple product (up to 10{sup 21} m{sup {minus}3} s keV), and energy confinement time (up to 330 ms). The maximum plasma current for access to high-performance supershots has been increased from 1.9 to 2.7 MA, leading to stable operation at plasma stored energy values greater than 5 MJ. The amount of lithium on the limiter and the effectiveness of its action are maximized through (1) distributing the Li over the limiter surface by injection of four Li pellets into Ohmic plasmas of increasing major and minor radius, and (2) injection of four Li pellets into the Ohmic phase of supershot discharges before neutral-beam heating is begun. {copyright} {ital 1996 American Institute of Physics.}

Mansfield, D.K.; Hill, K.W.; Strachan, J.D.; Bell, M.G.; Scott, S.D.; Budny, R.; Marmar, E.S.; Snipes, J.A.; Terry, J.L.; Batha, S.; Bell, R.E.; Bitter, M.; Bush, C.E.; Chang, Z.; Darrow, D.S.; Ernst, D.; Fredrickson, E.; Grek, B.; Herrmann, H.W.; Janos, A.; Jassby, D.L.; Jobes, F.C.; Johnson, D.W.; Johnson, L.C.; Levinton, F.M.; Mikkelsen, D.R.; Mueller, D.; Owens, D.K.; Park, H.; Ramsey, A.T.; Roquemore, A.L.; Skinner, C.H.; Stevenson, T.; Stratton, B.C.; Synakowski, E.; Taylor, G.; von Halle, A.; von Goeler, S.; Wong, K.L.; Zweben, S.J. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States); TFTR Group

1996-05-01

150

Biogas production from wheat straw and manure - Impact of pretreatment and process operating parameters.  

PubMed

Non-treated or steam-exploded straw in co-digestion with cattle manure was evaluated as a substrate for biogas production compared with manure as the sole substrate. All digestions were performed in laboratory-scale CSTR reactors (5L) operating with an organic loading late of approximately 2.8g VS/L/day, independent of substrate mixture. The hydraulic retention was 25days and an operating temperature of 37, 44 or 52°C. The co-digestion with steam exploded straw and manure was evaluated with two different mixtures, with different proportion. The results showed stable performance but low methane yields (0.13-0.21NLCH4/kg VS) for both manure alone and in co-digestion with the straw. Straw appeared to give similar yield as manure and steam-explosion treatment of the straw did not increase gas yields. Furthermore, there were only slight differences at the different operating temperatures. PMID:24121239

Risberg, Kajsa; Sun, Li; Levén, Lotta; Horn, Svein Jarle; Schnürer, Anna

2013-09-19

151

Biogas from waste seen as fuel option  

Microsoft Academic Search

Users with access to organic wastes have the option of producing biogas as an alternative fuel. With half the Btu content of natural gas, biogas costs only 40% as much to produce. The anaerobic biogas process results in a 60% methane and 40% carbon dioxide product, which can be used as a boiler fuel to generate power and run equipment

1983-01-01

152

Feasibility of biogas production on farms  

SciTech Connect

An overview of biogas technology is presented. The following topics are discussed: the potentials and limitations of anaerobic digestion; on-site energy generation: relationship of demand to supply; economics of farm-scale biogas production; design considerations of the biogas production system; gas utilization; safety guidelines and regulations; and operation, maintenance, and diagnostics of small methane generation systems. (MHR)

Jewell, W.J.; Adams, B.A.; Eckstrom, B.P.; Fanfoni, K.J.; Kabrick, R.M.; Sherman, D.F.

1982-01-01

153

Relation between Fodder and Biogas Yield.  

National Technical Information Service (NTIS)

Biogas production depends on the amount and quality of food fed to creatures, producing manure for biogas production. Results based on manure from cows, heifers and fattening calves, fed between 4 and 15 feed units (F.U.) per day, indicate that biogas pro...

N. Oestergaard

1985-01-01

154

Applicability of biogas digestate as solid fuel  

Microsoft Academic Search

Biogas digestate is a byproduct in biogas plants. Using the dried digestate as solid fuel seems to be a promising alternative. Objectives were to verify whether digestate from biogas plants is suitable as a solid biomass fuel and to classify the digestate according to current regulations for biofuels. Combustion experiments in a biomass combustion facility were carried out to ascertain

Martin Kratzeisen; Nikica Starcevic; Milan Martinov; Claudia Maurer; Joachim Müller

2010-01-01

155

Biogas in China 1981 - a Travel Report.  

National Technical Information Service (NTIS)

Biogas is formed by anaerobic fermentation of organic material. In China there are about seven million biogas units of family size distributed all over the country. Biogas is produced from manure,feces, domestic wastes and straw. The gas is used above all...

B. Frostell J. Norrman

1982-01-01

156

The feasibility of biogas production on farms  

NASA Astrophysics Data System (ADS)

Biogas technology is reviewed. The following topics are discussed: (1) the potentials and limitations of anaerobic digestion; (2) on site energy generation; (3) relationship of demand to supply; (4) economics of farm scale biogas production; (5) design considerations of the biogas production system; (6) gas utilization; (7) safety guidelines and regulations; and (8) operation, maintenance, and diagnostics of small methane generation systems.

Jewell, W. J.; Adams, B. A.; Eckstrom, B. P.; Fanfoni, K. J.; Kabrick, R. M.; Sherman, D. F.

1982-01-01

157

Biogas plasticization coupled anaerobic digestion: batch test results.  

PubMed

Biogas has unique properties for improving the biodegradability of biomass solids during anaerobic digestion (AD). This report presents batch test results of the first investigation into utilizing biogas plasticization to "condition" organic polymers during active digestion of waste activated sludge (WAS). Preliminary design calculations based on polymer diffusion rate limitation are presented. Analysis of the 20 degrees C batch test data determined the first order (k(1)) COD conversion coefficient to be 0.167 day(-1) with a maximum COD utilization rate of 11.25 g L(-1) day(-1). Comparison of these batch test results to typical conventional AD performance parameters showed orders of magnitude improvement. These results show that biogas plasticization during active AD could greatly improve renewable energy yields from biomass waste materials such as MSW RDF, STP sludges, food wastes, animal manure, green wastes, and agricultural crop residuals. PMID:17054122

Schimel, Keith A

2007-06-01

158

Effects of sawdust on biogas production from cowdung  

SciTech Connect

The biogas generation was performed using cowdung and sawdust in the ratios of 4:1 and 2:1, respectively. The experiments were also conducted using cowdung alone for the comparison purpose. The increase in the amount of sawdust in the mixture of cowdung and sawdust decreases the quantity of gas production. The production of methane up to three weeks is also effected by the amount of sawdust. The nitrogen contents increase and volatile solids decrease with the digestion of waste materials. The thermogravimetric studies of the materials support the biogas generation as the decomposition of particular part of cowdung.

Azmy, N.S. (Centre for Rural Development and Technology, Indian Inst. of Technology, Hauz Khas, New Delhi 110016 (IN)); Mishra, S. (Agriculture Research Centre, Soil and Water Research Inst., Microbiology Dept., Giza (EG)); Maheshwari, R.C. (Dept. of Chemistry, Birla Inst. of Technology and Science, Pilani, Rajasthan (IN))

1991-01-01

159

Review of Boiling Water Reactor Water Chemistry: Science, Technology, and Performance.  

National Technical Information Service (NTIS)

Boiling water reactor (BWR) water chemistry has been reviewed with an emphasis on the relationships between BWR water quality and corrosion, fuel performance, and radiation buildup. Plant performance with respect to BWR water chemistry has shown dramatic ...

M. J. Fox

1989-01-01

160

A comparison of CSTR and SBR bioslurry reactor performance  

Microsoft Academic Search

A continuous-flow stirred tank reactor (CSTR) and a soil slurry-sequencing batch reactor (SS-SBR) were maintained in 8 l vessels for 180 days to treat a diesel fuel-contaminated soil. The SS-SBR provided markedly enhanced contaminant degradation relative to the CSTR. Diesel fuel removal efficiency was 96% in the SS-SBR, compared with 75% in the CSTR. Microbial growth was approximately 25% greater in

Daniel P Cassidy; Samir Efendiev; Daniel M White

2000-01-01

161

Performance of inverse anaerobic fluidized bed reactor for treating high strength organic wastewater during start-up phase.  

PubMed

The aim of this work is to report on the physical characteristics of carrier material (perlite), biomass growth on the carrier material and the biogas production during an apparent steady state period in an inverse anaerobic fluidized bed reactor (IAFBR) for treating high strength organic wastewater. Before starting up the reactor, physical properties of the carrier material were determined. One millimeter diameter perlite particle is found to have a wet specific density of 295 kg/m(3) with specific surface area of 7.010 m(2)/g. This material has provided a good surface for biomass attachment and development. The biofilm concentration (in terms of attached volatile solids (AVS)) attached to carrier material was found to be 0.66 g(AVS)/g(solid). Most particles have been covered with a thin biofilm of uniform thickness. Once the inverse anaerobic fluidized bed system reached the steady state, the organic load was increased step wise by reducing hydraulic retention time (HRT) from 2 days to 0.16 day, while maintaining the constant feed of chemical oxygen demand (COD) concentration. This system has achieved 84% COD removal and reached the biogas production of 13.22 l/l/d at an organic loading rate (OLR) of 35 kgCOD/m(3)/d. PMID:18191565

Sowmeyan, R; Swaminathan, G

2008-01-10

162

Biogas in Nepal--Retrospects and prospects  

SciTech Connect

The tremendous need and potential of biogas in Nepal, supported by a very large cattle population, seems to be primarily limited by manpower and budgetary constraints and poor planning and implementation. Besides cooking and lighting, considerable potential, particularly at the rural level exists for biogas powered agro-processing applications such as rice hulling, oil expelling and flour grinding. Experience has shown that such applications, for which equipment is easily available, can be better served by community Biogas plants. The government of Nepal, with assistance from international organizations such as the Asian Development Bank, is strengthening the Biogas Company and taking other appropriate measures to disseminate and establish biogas on a firm footing.

Sood, D.K.

1983-12-01

163

Developing a Comprehensive Software Suite for Advanced Reactor Performance and Safety Analysis  

SciTech Connect

This paper provides an introduction to the reactor analysis capabilities of the nuclear power reactor simulation tools that are being developed as part of the U.S. Department of Energy s Nuclear Energy Advanced Modeling and Simulation (NEAMS) Toolkit. The NEAMS Toolkit is an integrated suite of multi-physics simulation tools that leverage high-performance computing to reduce uncertainty in the prediction of performance and safety of advanced reactor and fuel designs. The Toolkit effort is comprised of two major components, the Fuels Product Line (FPL), which provides tools for fuel performance analysis, and the Reactor Product Line (RPL), which provides tools for reactor performance and safety analysis. This paper provides an overview of the NEAMS RPL development effort.

Pointer, William David [ORNL; Bradley, Keith S [ORNL; Fischer, Paul F [ORNL; Smith, Micheal A [ORNL; Tautges, Timothy J [ORNL; Ferencz, Robert M [ORNL; Martineau, Richard C [ORNL; Jain, Rajeev [ORNL; Obabko, Aleksandr [Argonne National Laboratory (ANL); Billings, Jay Jay [ORNL

2013-01-01

164

Anaerobic treatment of coconut husk liquor for biogas production.  

PubMed

The market for coconut water causes environmental problems as it is one of the major agro-industrial solid wastes in some developing countries. With the aim of reusing the coconut husk, Embrapa developed a system for processing this raw material. During the dewatering stage Coconut Husk Liquor (CHL) is generated with chemical oxygen demand (COD) varying from 60 to 70 g/L due to high concentrations of sugars and tannins. The present study evaluated the feasibility of anaerobic treatment of CHL through Anaerobic Toxicity Assay and the operation of a lab-scale Upflow Anaerobic Sludge Blanket (UASB) reactor. Results showed that CHL can be treated through a UASB reactor operating with an OLR that reaches up to 10 kg/m3.d and that is maintained stable during the whole operation. With this operational condition, the removal efficiency was higher than 80% for COD and approximately 78% for total tannins, and biogas production was 20 m3 of biogas or 130 KWh per m3 of CHL. Seventy-five percent of the biogas composition was methane and toxicity tests demonstrated that CHL was not toxic to the methanogenic consortia. Conversely, increasing the concentration of CHL leads to increased methanogenic activity. PMID:19448321

Leitão, R C; Araújo, A M; Freitas-Neto, M A; Rosa, M F; Santaella, S T

2009-01-01

165

Comparison of reactor performance in the nonthermal plasma chemical processing of hazardous air pollutants  

Microsoft Academic Search

The performances of three different types of plasma reactors such as ferroelectric packed-bed (FPB), pulsed corona (PCR), and silent discharge (SDP) were compared in the decomposition of trichloroethylene (Cl2C=CHCl, TCE), bromomethane (CH3Br), and tetrafluoromethane (CF4). Irrespective of reactors, HAP (hazardous air pollutants) reactivity decreased in the order: TCE>CH 3Br>CF4. Similar byproducts were obtained with any of the above reactors, and

Shigeru Futamura; Hisahiro Einaga; Aihua Zhang

1999-01-01

166

Microalgal reactors: a review of enclosed system designs and performances.  

PubMed

One major challenge to industrial microalgal culturing is to devise and develop technical apparata, cultivation procedures and algal strains susceptible of undergoing substantial increases in efficiency of use of solar energy and carbon dioxide. Despite several research efforts developed to date, there is no such thing as "the best reactor system"- defined, in an absolute fashion, as the one able to achieve maximum productivity with minimum operation costs, irrespective of the biological and chemical system at stake. In fact, choice of the most suitable system is situation-dependent, as both the species of alga available and the final purpose intended will play a role. The need of accurate control impairs use of open-system configurations, so current investigation has focused mostly on closed systems. In this review, several types of closed bioreactors described in the technical literature as able to support production of microalgae are comprehensively presented and duly discussed, using transport phenomenon and process engineering methodological approaches. The text is subdivided into subsections on: reactor design, which includes tubular reactors, flat plate reactors and fermenter-type reactors; and processing parameters, which include gaseous transfer, medium mixing and light requirements. PMID:17137294

Carvalho, Ana P; Meireles, Luís A; Malcata, F Xavier

167

U.S. Air Force performance-based training as applied to TRIGA reactor operations  

SciTech Connect

In January 1991 the Air Force Safety Agency (AFSA) licensed a nuclear reactor for operation at McClellan Air Force Base in Sacramento, California. McClellan's TRIGA reactor provides a neutron source for the Sacramento Air Logistics Center's nondestructive inspection facilities. The reactor is also used extensively for both Department of Defense and commercial neutron irradiations. The key to safe and reliable reactor operations lies with the operations staff. The reactor operators at the McClellan TRIGA reactor are civil service employees. The initial reactor operators received training from General Atomics in San Diego, California. Once the reactor became fully operational, however, additional candidate operators were added to the staff. Experience showed that the time from hiring a candidate operator to certification was about two years. The McClellan reactor operator training program was vastly improved through the initiation of two significant.changes. First, a new level of reactor operator, the reactor console operator (RCO) was established. Second, a performance based training program was developed and implemented. The new RCO operator level brought several efficiencies to the reactor operator training and certification process. Like an RO, the RCO must have the knowledge and skills to operate the reactor during normal, abnormal and emergency conditions. However, RCOs are not certified to perform reactor related maintenance or fuel handling activities. RCO candidates concentrate on reactor operations, while reactor related maintenance and fuel handling training remains at the RO level. The result is a shorter initial training period, with certification to RCO in about six months. The second significant change was the development and implementation of a performance based training program. This required an in depth analysis of the responsibilities of all three operator levels (RCO, RO, SRO). The performance based training program ensures that the required training is delivered to a candidate at the correct time, and at the correct level in their training process. Overtraining is minimized and undertraining is eliminated, resulting in an efficient and effective reactor operator training program. (author)

Brauer, W.C.; Weeks, A.A. [SM-ALC/TIR, 5335 Price Ave., McClellan Air Force Base Sacramento, CA 95652-2504 (United States)

1994-07-01

168

Biogas, compost and fuel cells  

Microsoft Academic Search

A pilot project now under development in Folsom, California, incorporates an anaerobic digestion\\/aerobic composting process that could eventually supply enough biogas to a fuel cell. The Sacramento Municipal Utility District (SMUD) has two fuel cells in operation and is participating in the research project. Recently, the California Prison Industry Authority (PIA) began operating a processing facility at the Folsom prison,

B. Wichert; L. Wittrup; R. Robel

1994-01-01

169

Biogas project advances in California  

SciTech Connect

The National Renewable Energy Laboratory (NREL) has given a `thumbs up` rating to the high solids anaerobic digester project which is designed to produce biogas. The Sacramento Municipal Utility District (SMUD), the local utility, is considering the use of biogas to run a fuel cell pilot project. The designs for the three digesters are state-of-the-art, with each containing a horizontal trough measuring 120 feet long, 32 feet wide and 22 feet tall. NREL was asked by the PIA to review the mixing method in the digesters and analyze the overall potential success of the operation. The design employs a redundant system for foam removal from the digester gas, and has provisions to remove moisture from the biogas. However, there are no systems specified to reduce hydrogen sulfide levels. Since hydrogen sulfide is known to be corrosive, it may be destructive to the ultimate use as biogas in fuel cells. A suggested remedy from NREL is to add redundant iron sponge systems to remove hydrogen sulfide gases. A redundant system would allow regenerating one while the other is in service. In general, the lab found the design offers low construction costs, relative ease of operation, and a reasonably high level of anticipated success in operation. Therefore, NREL recommends proceeding with the current digester design plans, once the modifications as indicated are made.

Wittrup, L. [Sacramento Municipal Utility District, CA (United States)

1995-04-01

170

Operating Experience Feedback Report. Human Performance in Operating Events. Commercial Power Reactors.  

National Technical Information Service (NTIS)

The report describes the results of a Nuclear Regulatory Commission (NRC) program begun in 1990 to conduct onsite, in depth studies of human performance that affected reactor safety during selected power reactor events. The purpose of the program is to id...

J. V. Kauffman G. F. Lanik R. A. Spence E. A. Trager

1992-01-01

171

Performance of Liquid Metals in Natural Circulation Cooled Nuclear Reactors  

Microsoft Academic Search

The inherent safety capability of natural circulation makes reactor design more reliable. Additionally, the construction and operation of a nuclear power plant with natural circulation in the primary cooling circuit is an interesting alternative for nuclear plant designers, due to their lower operational and investment costs obtained by simplifying systems and controls. This paper deals with the feasibility of application

Carlos Ceballos; Danny Lathouwers; Adrian Verkooijen

2004-01-01

172

RETRACTED ARTICLE: The Evaluation of Reactor Performance by using Flibe and Flinabe Molten Salts in the APEX Hybrid Reactor  

NASA Astrophysics Data System (ADS)

The modeling of APEX hybrid reactor, produced by using ARIES-RS hybrid reactor technology, has been performed by using the MCNP-4B computer code and ENDF/B-V-VI nuclear data. Around the fusion chamber, molten salts Flibe (Li2BeF4) and Flinabe (LiNaBeF4) were used as cooling materials. APEX reactor was modeled in the torus form by adding nuclear materials of low significance in the specified percentages between percent 0-12 to the molten salts. The result of the study indicated that fissile material production, UF4 and ThF4 heavy metal salt increased nearly at the same percentage and it was observed that the percentage of it was practically the same in both materials. In order for the hybrid reactor to work itself in terms of tritium, TBR (tritium breeding ratio) should be lower than 1.05. When flibe molten salt was utilized in the APEX hybrid reactor, TBR was calculated as >1, 22 and when flinabe molten salt was used, TBR was calculated as >1.06.

Korkut, Turgay; Hançerlio?ullar?, Aybaba

2012-04-01

173

Integral experiment information for fast reactors: Sensitivity and uncertainty analysis of reactor performance parameters  

Microsoft Academic Search

This chapter offers a detailed analysis of uncertainties in experimental parameters for the ZPR benchmark cores. Discusses the critical facilities and measurements; the need for well documented data; the relevance of data for reactor design; uses of integral data; benchmark data; mockup cores; accuracy of experimental data; critical mass; reaction rate ratios; covariance matrices; selection of reliable integral data; cavity

1982-01-01

174

Performance of electrochemical reactor for treatment of tannery wastewaters  

Microsoft Academic Search

An undivided electrochemical reactor with parallel plate Ti\\/Pt–Ir anode and stainless-steel cathode was used to treat tannery wastewater at constant current densities and different stirring rates. The pollutants were depleted by direct anodic oxidation and\\/or indirect electro-oxidation, mediated by active chlorine formed in situ, so that chemical oxygen demand, total organic carbon, tannin, sulfide, total Kjeldahl nitrogen and ammonium ion

Lidia Szpyrkowicz; Geoffrey H. Kelsall; Santosh N. Kaul; Marco De Faveri

2001-01-01

175

Assets and irradiation performance of the silene reactor  

Microsoft Academic Search

The need to study the behavior and the consequences of a criticality accident led the Nuclear Protection and Safety Institute in 1974 to design and build an experimental facility called Silene at the site of Valduc, France. The reactor is in the form of a small annular vessel in which a fissile solution of uranyl nitrate is designed to {open_quotes}diverge{close_quotes}

B. Tournier; F. Barby; B. Verrey

1997-01-01

176

Enhancement of Tokamak Fusion Test Reactor performance by lithium conditioning  

Microsoft Academic Search

Wall conditioning in the Tokamak Fusion Test Reactor (TFTR) [K. M. McGuire etal., Phys. Plasmas 2, 2176 (1995)] by injection of lithium pellets into the plasma has resulted in large improvements in deuterium–tritium fusion power production (up to 10.7 MW), the Lawson triple product (up to 1021 m?3 s keV), and energy confinement time (up to 330 ms). The maximum

D. K. Mansfield; K. W. Hill; J. D. Strachan; M. G. Bell; S. D. Scott; R. Budny; E. S. Marmar; J. A. Snipes; J. L. Terry; S. Batha; R. E. Bell; M. Bitter; C. E. Bush; Z. Chang; D. S. Darrow; E. Fredrickson; B. Grek; H. W. Herrmann; A. Janos; D. L. Jassby; F. C. Jobes; D. W. Johnson; L. C. Johnson; F. M. Levinton; D. R. Mikkelsen; D. Mueller; D. K. Owens; A. T. Ramsey; A. L. Roquemore; C. H. Skinner; T. Stevenson; B. C. Stratton; E. Synakowski; G. Taylor; A. von Halle; S. von Goeler; K. L. Wong; S. J. Zweben

1996-01-01

177

Nitrogen removal performance of a hybrid anammox reactor.  

PubMed

The anaerobic ammonium oxidation (anammox) process has attracted considerable attention in recent years as an alternative to conventional nitrogen removal technologies. In this study, an innovative hybrid reactor combining fluidized and fixed beds for anammox treatment was developed. The fluidized bed was mechanically stirred and the gaseous product could be rapidly released from the anammox sludge to prevent washout of the sludge caused by flotation. The fixed bed comprising a non-woven biomass carrier could efficiently catch sludge to reduce washout. During the operation, nitrogen loading rates to the reactor were increased to 27.3 kg N/m(3)/d, with total nitrogen removal efficiencies of 75%. The biomass concentration in the fluidized bed reached 26-g VSS/L. Anammox granules were observed in the reactors, with settling velocities and sludge volumetric index of 27.3 ± 6.5m/h and 23 mL/g, respectively. Quantification of extracellular polymeric substances revealed the anammox granules contained a significant amount of extracellular proteins. PMID:21507626

Ma, Yongguang; Hira, Daisuke; Li, Zhigang; Chen, Cheng; Furukawa, Kenji

2011-03-29

178

Family and Community Biogas Plants in Rural India and China.  

National Technical Information Service (NTIS)

This report contains the basic theory of biogas production, tables of expected production, installation costs, architectural diagrams for both the Indian and Chinese plants, a case for community biogas plants in India, a pilot community biogas scheme in U...

R. Roy

1980-01-01

179

How China utilizes biogas in rural areas  

SciTech Connect

An outline is presented of how China utilizes biogas in rural areas. Already, 7,140,000 small biogas digesters have been built. Sichuan province has 4,160,000 digesters including about 20,000 large digesters which operate diesel engines to generate electricity. This is seen as the key area for further research and development. In rural areas, biogas is used principally for cooking and to power stationary units such as grinding mills, electric generators and crop driers.

Ji, M.

1981-05-01

180

Biogas from waste seen as fuel option  

SciTech Connect

Users with access to organic wastes have the option of producing biogas as an alternative fuel. With half the Btu content of natural gas, biogas costs only 40% as much to produce. The anaerobic biogas process results in a 60% methane and 40% carbon dioxide product, which can be used as a boiler fuel to generate power and run equipment or sold to gas utilities for further processing as a pipeline fuel. Transportation costs make ready access to manure or garbage essential. (DCK)

Tucker, L.

1983-01-24

181

Life-cycle energy production and emissions mitigation by comprehensive biogas-digestate utilization.  

PubMed

In the context of global energy shortages and climate change, developing biogas plants with links to agricultural system has become an important strategy for cleaner rural energy and renewable agriculture. In this study, a life-cycle energy and environmental assessment was performed for a biogas-digestate utilization system in China. The results suggest that biogas utilization (heating, illumination, and fuel) and comprehensive digestate reuse are of equal importance in the total energy production of the system, and they also play an important role in systemic greenhouse gas mitigation. Improvement can be achieved in both energy production and emissions mitigation when the ratio of the current three biogas utilization pathways is adjusted. Regarding digestate reuse, a tradeoff between energy and environmental performance can be obtained by focusing on the substitution for top-dressing, base fertilizers, and the application to seed soaking. PMID:22513252

Chen, Shaoqing; Chen, Bin; Song, Dan

2012-04-02

182

Investigations for biogas operated MHD power generators  

SciTech Connect

Biogas is produced from the anaerobic fermentation of the organic matter containing cellulose, such as agricultural wastes, human wastes, animal wastes, etc. It contains methane (50-70%), carbon dioxide (30-50%), and very small amounts of hydrogen and hydrogen sulphide. Adequate quantities of raw material to generate biogas are normally available in rural areas, and therefore, there is a possibility that almost all the energy requirements of the rural sector may be fulfilled by biogas. Presently in the rural sector, biogas is used mainly to provide thermal energy (for cooking, etc.), and up to a limited extent, to meet the electrical energy requirements by running electrical generators with engines powered by a mixture of oil and biogas. In this paper, the authors propose a scheme in which biogas can be used to generate electricity more efficiently by using magnetohydrodynamic (MHD) power generators. Investigations have been carried out to make feasibility studies for biogas-operated open cycle MHD power generators. Composition, temperature and electrical conductivity of the seeded (with potassium) combustion products of biogas-air/oxygen systems have been analytically investigated for different percentages of CO/sub 2/ in biogas and at various combustor pressures for a seeding ratio of 1 percent by weight. The effect of preheating and enrichment of air on temperature and electrical conductivity of the seeded combustion plasmas has also been studied.

Dahiya, R.P.; Chand, A.; Sharma, S.C.

1983-12-01

183

Biotechnological intensification of biogas production  

Microsoft Academic Search

The importance of syntrophic relationships among microorganisms participating in biogas formation has been emphasized, and\\u000a the regulatory role of in situ hydrogen production has been recognized. It was assumed that the availability of hydrogen may\\u000a be a limiting factor for hydrogenotrophic methanogens. This hypothesis was tested under laboratory and field conditions by\\u000a adding a mesophilic (Enterobacter cloacae) or thermophilic hydrogen-producing

Zoltán Bagi; Norbert Ács; Balázs Bálint; Lenke Horváth; Krisztina Dobó; Katalin R. Perei; Gábor Rákhely; Kornél L. Kovács

2007-01-01

184

Assets and irradiation performance of the silene reactor  

SciTech Connect

The need to study the behavior and the consequences of a criticality accident led the Nuclear Protection and Safety Institute in 1974 to design and build an experimental facility called Silene at the site of Valduc, France. The reactor is in the form of a small annular vessel in which a fissile solution of uranyl nitrate is designed to {open_quotes}diverge{close_quotes} by withdrawing a control rod. This intense source of neutron and gamma radiation soon proved to be an exceptional research tool, whose scope largely exceeded that of criticality. The reasons for this success and SILENE`s extended polyvalence result from its main assets, which are presented here.

Tournier, B.; Barby, F.; Verrey, B. [Commissariat a l`Energie Atomique, Is sur Tille (France)] [and others

1997-12-01

185

Mixed-amine Modified SBA15 as Novel Adsorbent of CO2 Separation for Biogas Upgrading  

Microsoft Academic Search

A novel adsorbent of CO2 from biogas was prepared by synthesizing and modifying the mesoporous molecular silica of SBA-15 with methyl-diethyl-amine (MDEA) and piperazine (PZ). The adsorbent showed good performance in separating CO2 from biogas. The loaded amines did not change the ordered structure of SBA-15, but enhanced its adsorption of CO2. The adsorbents were characterized by X-ray powder diffraction

Quanmin Xue; Yingshu Liu

2011-01-01

186

Nutrient balance of a two-phase solid manure biogas plant  

Microsoft Academic Search

The Biodynamic Research Institute in Järna developed a two-phase on-farm biogas plant. The plant digests manure of dairy cattle and organic residues originating from the farm and the surrounding food processing units containing 17.7-19.6 % total solids. A new technology for continuously filling and discharging the hydrolysis reactor was developed and implemented. The output of the hydrolysis reactor is separated

Winfried Schäfer; Lars Evers; Marja Lehto; Sanna Sorvala; Frederick. Teye

187

Biogas from manure - a new technology to close the nutrient and energy circuit on-farm  

Microsoft Academic Search

The Biodynamic Research Institute in Järna developed a two-phase on-farm biogas plant. The plant digests manure of dairy cattle and organic residues originating from the farm and the surrounding food processing units containing 17.7-19.6 % total solids. A new technology for continuously filling and discharging the hydrolysis reactor was developed and implemented. The output of the hydrolysis reactor is separated

W. Schäfer; L. Evers; M. Lehto; S. Sorvala; F. Teye; A. Granstedt

188

Comparative performance of UASB and anaerobic hybrid reactors for the treatment of complex phenolic wastewater.  

PubMed

The performance of an upflow anaerobic sludge blanket (UASB) reactor and an anaerobic hybrid reactor (AHR) was investigated for the treatment of simulated coal wastewater containing toxic phenolics at different hydraulic retention times (0.75-0.33d). Fast start-up and granulation of biomass could be achieved in an AHR (45d) than UASB (58d) reactor. Reduction of HRT from 1.5 to 0.33d resulted in a decline in phenolics removal efficiency from 99% to 77% in AHR and 95% to 68% in UASB reactor respectively. AHR could withstand 2.5 times the selected phenolics loading compared to UASB reactor that could not withstand even 1.2 times the selected phenolics loading. Residence time distribution (RTD) study revealed a plug flow regime in the AHR and completely mixed regime in UASB reactor respectively. Energy economics of the reactors revealed that 12,159MJd(-1) more energy can be generated using AHR than UASB reactor. PMID:22940341

Ramakrishnan, Anushuya; Surampalli, Rao Y

2012-07-27

189

Advanced Concepts for Pressure-Channel Reactors: Modularity, Performance and Safety  

Microsoft Academic Search

Based on an analysis of the development of advanced concepts for pressure-tube reactor technology, we adapt and adopt the pressure-tube reactor advantage of modularity, so that the subdivided core has the potential for optimization of the core, safety, fuel cycle and thermal performance independently, while retaining passive safety features. In addition, by adopting supercritical water-cooling, the logical developments from existing

Romney B. Duffey; Igor L. Pioro; Sermet Kuran

2008-01-01

190

A pilot-scale photocatalyst-membrane hybrid reactor: performance and characterization  

Microsoft Academic Search

We developed and tested a pilot-scale photocatalyst-membrane hybrid reactor for water treatment. The performance of the pilot-scale reactor was evaluated by monitoring the degradation efficiency of several organic pollutants and the membrane suction pressure at different operating conditions. The concentration of humic acids rather increased in the initial period of UV illumination and then decreased gradually, which could be ascribed

J. Ryu; W. Choi; K.-H. Choo

191

Effects of Dust Characteristics on Hot-Gas Filter Performance in a Transport Reactor System  

Microsoft Academic Search

This paper discusses the use of in-situ particulate sampling and ash characterization in analyzing the performance of a hot-gas filter installed on a transport reactor system at the Power Systems Development Facility (PSDF). In- situ measurements of the particulate loadings entering and leaving the hot-gas filter have been made during combustion-mode operation of the transport reactor system with four different

R. S. Dahlin; E. C. Landham

192

Performance of a hybrid anaerobic baffled reactor (HABR) treating brewery wastewater  

Microsoft Academic Search

The performance and the characteristics of a laboratory scale hybrid anaerobic baffled reactor (HABR) were investigated using synthetic brewery wastewater. The reactor had been operated continuously at 35°C for 109d, with organic loading rate (OLR) increased from 1.2 to 5.6 kg COD\\/(m3 · d). The results demonstrated that the system was very effective in the treatment of the high-strength wastewater,

Li Hui-ting; Li Yong-feng

2010-01-01

193

Comparison of reactor performance in the nonthermal plasma chemical processing of hazardous air pollutants  

Microsoft Academic Search

The performance of three different types of plasma reactors such as ferroelectric packed-bed (FPR), pulsed corona (PCR), and silent discharge (SDR) were compared in the decomposition of trichloroethylene (Cl2C=CHCl, TCE), bromomethane (CH3Br), and tetrafluoromethane (CF4). Irrespective of reactors, hazardous air pollutant (HAP) reactivity in dry N2 decreased in the order: TCE>CH3Br>CF4. Similar byproducts were obtained with any of the above

Shigeru Futamura; Hisahiro Einaga; Aihua Zhang

2001-01-01

194

The performance in a fluidized bed reactor of photocatalysts immobilized onto inert supports  

Microsoft Academic Search

The performance of a model photocatalyst (Degussa P25), immobilized onto quartz sand using a dry\\/wet physical deposition method has been studied in a fluidized-bed reactor. A simple model substrate, dilute oxalic acid, was mineralized at room temperature. For comparison purposes, a slurry of the powdery P25 was also used.The reactor apparent captured power (PC) and the apparent quantum efficiency (?VR)

Roberto L Pozzo; José L Giombi; Miguel A Baltanás; Alberto E Cassano

2000-01-01

195

FUNCTION AND PERFORMANCE OF A PRE?REACTOR TO A REACTIVE DISTILLATION COLUMN FOR BIODIESEL PRODUCTION  

Microsoft Academic Search

This article describes an in?depth follow?up to previous studies showing that an oil?methanol mixer prior to an RD reactor played an important role in enhancing the overall performance of the RD reactor system. An in?line static mixer was used for the purpose of providing initial mixing of the reactants, heating the mixture up to the desired operating temperature, and carrying

B. B. He; A. P. Singh; J. C. Thompson

196

Progress and Recent Trends in Biogas Processing  

Microsoft Academic Search

In this study, progresses and recent trends in biogas processing are reviewed. Biogas is generated from biomass by digestion under anaerobic conditions in the presence of microorganisms. Anaerobic digestion occurs in the absence of air and is typically carried out for a few weeks. The anaerobic digestion process occurs in the following four basic steps: (1) hydrolysis, (2) acidogenesis, (3)

M. Fatih Demirbas; Mehmet Balat

2009-01-01

197

Investigations for biogas operated MHD power generators  

Microsoft Academic Search

Biogas is produced from the anaerobic fermentation of the organic matter containing cellulose, such as agricultural wastes, human wastes, animal wastes, etc. It contains methane (50-70%), carbon dioxide (30-50%), and very small amounts of hydrogen and hydrogen sulphide. Adequate quantities of raw material to generate biogas are normally available in rural areas, and therefore, there is a possibility that almost

R. P. Dahiya; A. Chand; S. C. Sharma

1983-01-01

198

Essential technical parameters for effective biogas production  

Microsoft Academic Search

Rising agrarian raw material prices in 2006 had a negative impact on the biogas sector in Germany, leading to the search for potentials for optimisation of production. A problem is the workload of the block-type thermal power station (BTPS). This is caused by biogas process disturbances, construction errors, technical problems and management mistakes as well as by oversizing of the

M. Schlegel; N. Kanswohl; D. Rössel; A. Sakalauskas

199

Development of biogas technology in India  

SciTech Connect

Biogas from organic wastes is a potential renewable energy to meet the domestic energy needs in India. The fundamentals of bio-gasification by anaerobic digestion are presented. The production of biogas from cattle manure in small anaerobic digesters is discussed illustrating with a popular digester model. 9 refs.

Chiranjivi, C.; Raviprasad, A.; Rao, K.V.

1981-01-01

200

Biogas, membranes and carbon dioxide capture  

Microsoft Academic Search

Biogas, which consists primarily of methane, can be obtained through the biological transformation of a large variety of organic wastes, and has drawn an increased interest within a framework of renewable energy sources. The use of gas permeation membranes for upgrading biogas (i.e., for removing carbon dioxide and hydrogen sulfide from biomethane) has been abundantly investigated and already displays practical

Eric Favre; Roda Bounaceur; Denis Roizard

2009-01-01

201

BIOGAS PRODUCTION FROM FRESH MAIZE BIOMASS  

Microsoft Academic Search

There is a need to find acceptable energy crops for biogas production for the climatic and soil conditions in Latvia. The average annual dry matter yields from maize vary from 12 to 16 t·ha -1 under the climatic conditions in Latvia. Biogas yield from fresh maize biomass was investigated in dependence on the harvesting time of maize. The maize varieties

Vilis Dubrovskis; Imants Plume; Janis Bartusevics; Vladimirs Kotelenecs

2010-01-01

202

Factors influencing the degradation of garbage in methanogenic bioreactors and impacts on biogas formation.  

PubMed

Anaerobic digestion of garbage is attracting much attention because of its application in waste volume reduction and the recovery of biogas for use as an energy source. In this review, various factors influencing the degradation of garbage and the production of biogas are discussed. The surface hydrophobicity and porosity of supporting materials are important factors in retaining microorganisms such as aceticlastic methanogens and in attaining a higher degradation of garbage and a higher production of biogas. Ammonia concentration, changes in environmental parameters such as temperature and pH, and adaptation of microbial community to ammonia have been related to ammonia inhibition. The effects of drawing electrons from the methanogenic community and donating electrons into the methanogenic community on methane production have been shown in microbial fuel cells and bioelectrochemical reactors. The influences of trace elements, phase separation, and co-digestion are also summarized in this review. PMID:22395906

Morita, Masahiko; Sasaki, Kengo

2012-03-08

203

An innovative fuel design concept for improved light water reactor performance and safety. Final technical report  

SciTech Connect

Light water reactor (LWR) fuel performance is limited by thermal and mechanical constraints associated with the design, fabrication, and operation of fuel in a nuclear reactor. The purpose of this research was to explore a technique for extending fuel performance by thermally bonding LWR fuel with a non-alkaline liquid metal alloy. Current LWR fuel rod designs consist of enriched uranium oxide (UO{sub 2}) fuel pellets enclosed in a zirconium alloy cylindrical clad. The space between the pellets and the clad is filled by an inert gas. Due to the thermal conductivity of the gas, the gas space thermally insulates the fuel pellets from the reactor coolant outside the fuel rod, elevating the fuel temperatures. Filling the gap between the fuel and clad with a high conductivity liquid metal thermally bonds the fuel to the cladding, and eliminates the large temperature change across the gap, while preserving the expansion and pellet loading capabilities. The resultant lower fuel temperature directly impacts fuel performance limit margins and also core transient performance. The application of liquid bonding techniques to LWR fuel was explored for the purposes of increasing LWR fuel performance and safety. A modified version of the ESCORE fuel performance code (ESBOND) has been developed under the program to analyze the in-reactor performance of the liquid metal bonded fuel. An assessment of the technical feasibility of this concept for LWR fuel is presented, including the results of research into materials compatibility testing and the predicted lifetime performance of Liquid Metal Bonded LWR fuel.

Tulenko, J.S.; Connell, R.G.

1995-07-01

204

Prediction of thermal-hydraulic performance of gas-cooled fast breeder reactors. Final report  

Microsoft Academic Search

The report describes work performed under a project to examine the thermal-hydraulic performance of gas-cooled fast breeder reactors (GCFRs). Existing GCFR designs are briefly described with emphasis on the core cooling and associated systems. Factors affecting the convective heat transfer and pressure drop in the core are examined, particularly the effects of surface roughness on the enhancement of heat transfer,

C. Jr. Gazley; G. H. Harpole; L. S. Yao; W. H. Krase; J. Catton; J. Grzesik; W. Matyskiela

1977-01-01

205

Performance analysis of methanol-fueled solid oxide fuel cell system incorporated with palladium membrane reactor  

Microsoft Academic Search

The paper presents preliminary results from the performance analysis of a methanol-fueled solid oxide fuel cell (SOFC) system incorporated with a palladium membrane reactor. A conventional SOFC system comprises major components of preheaters, a reformer, an SOFC unit and a burner. The performance of the SOFC unit was dependent on operating current density, fuel utilization and temperature. When the conventional

W. Sangtongkitcharoen; S. Vivanpatarakij; N. Laosiripojana; A. Arpornwichanop; S. Assabumrungrat

2008-01-01

206

Sodium effects on mechanical performance and consideration in high temperature structural design for advanced reactors  

Microsoft Academic Search

Sodium environmental effects are key limiting factors in the high temperature structural design of advanced sodium-cooled reactors. A guideline is needed to incorporate environmental effects in the ASME design rules to improve the performance reliability over long operating times. This paper summarizes the influence of sodium exposure on mechanical performance of selected austenitic stainless and ferritic\\/martensitic steels. Focus is on

K. Natesan; Meimei Li; O. K. Chopra; S. Majumdar

2009-01-01

207

System for the production of biogas and compost from organic materials and method of operating an organic treatment facility  

US Patent & Trademark Office Database

A system and method for continuous decomposition of organic material to produce biogas and compost in which successive reactor zones in a primary reactor are used in turn to receive organic material which is decomposed in situ anaerobically followed by aerobic decomposition and excavation of raw compost from the same reactor zone where it is received into the organic treatment facility. Organic rich liquor recovered during anaerobic decomposition is further decomposed in a secondary reactor from which spent liquor is returned to the primary reactor while biogas harnessed from both the primary and secondary reactors is treated, and optionally used to fuel the operation of the organic treatment facility or for sale as fuel or electricity.

2006-09-05

208

Indian Experience in Performance of Light Water Reactor Fuel Elements.  

National Technical Information Service (NTIS)

Under a programme to assess the performance of fuel elements of Tarapur Atomic Power Station, post-irradiation examination has been carried out on some elements. The examination has revealed two modes of fuel element failure - stress corrosion cracking an...

J. K. Bahl P. R. Roy D. N. Sah K. C. Sahoo K. S. Sivaramakrishnan

1978-01-01

209

Thermal energy from a biogas engine/generator system  

SciTech Connect

A biogas fueled engine/generator equipped with heat recovery apparatus and thermal storage is described. The thermal energy is used to fuel a liquid fuel plant. Heat recovery is quantified and the static and dynamic performance of the thermal storage is described. At 1260 rpm the engine/generator produces 21 kW of electric power and 2500 kJ/min of thermal energy.

Stahl, T.; Fischer, J.R.; Harris, F.D.

1982-12-01

210

Biogas Purification Process to Increase GenSet Efficiency  

Microsoft Academic Search

Because of global issue about limited energy, biogas was one of alternative energy and save energy in the world which produced from biomass especially from cow manure. Most of biogas which produced from cow manure contains 40-75% methane as energy resources and another gas as impurities. Methane concentration of biogas has relation with biogas energy value, especially for application as

Satriyo Krido Wahono; Roni Maryana; M. Kismurtono

2009-01-01

211

Biogas plants in Denmark: technological and economic developments  

Microsoft Academic Search

Biogas plants are one of the important elements in the Danish energy-policy of having reduced CO2 emissions by 20% by 2005. Since 1984, development efforts concerning centralised biogas plants in Denmark have been carried out, and Denmark now has approximately 20 large centralised biogas plants. All Danish biogas plants have increased gas production as a result of admixing industrial organic

H. Mæng; H. Lund; F. Hvelplund

1999-01-01

212

Technical\\/economic\\/environmental analysis of biogas utilisation  

Microsoft Academic Search

Biogas may be utilised for Combined Heat and Power (CHP) production or for transport fuel production (CH4-enriched biogas). When used to produce transport fuel either electricity is imported to power the plant or some of the biogas is used in a small CHP unit to meet electricity demand on site. The potential revenue from CH4-enriched biogas when replacing petrol is

J. D. Murphy; E. McKeogh; G. Kiely

2004-01-01

213

Quantifying temperature and flow rate effects on the performance of a fixed-bed chromatographic reactor.  

PubMed

Chromatographic reactors are based on coupling chemical reactions with chromatographic separation in fixed-beds. Temperature and flow rate are important parameters for the performance of such reactors. Temperature affects mainly adsorption, chemical equilibria, mass transfer and reaction kinetics, whereas flow rate influences residence time and dispersion. In order to evaluate the mentioned effects, the hydrolysis reactions of methyl formate (MF) and methyl acetate (MA) were chosen as case studies. These reactions were performed experimentally in a lab-scale fixed-bed chromatographic reactor packed with a strong acidic ion exchange resin. The chosen reactions can be considered to represent a relative fast (MF) and a relative slow (MA) reaction. The processes which take place inside the reactor were described and simulated using an isothermal equilibrium dispersive model. The essential model parameters were determined experimentally at different temperatures and flow rates. The performance of the chromatographic reactor was evaluated at several discrete constant temperature levels by quantifying product purity, productivity and yield. The work provides insight regarding the influence of temperature and flow rate on values of the model parameters and the performance criteria. PMID:21963179

Vu, Tien D; Seidel-Morgenstern, A

2011-09-14

214

Investigation on the Neutronic Performance of a Fusion Reactor Using Flibe with Heavy Metal Fluorides  

NASA Astrophysics Data System (ADS)

Using liquid wall between the plasma and solid first wall in a fusion reactor allows to use high neutron wall loads and could eliminate frequent replacement of the first wall structure during reactor's lifetime. Liquid wall should have a certain effective or optimum thickness to extend solid first wall lifetime to reactor's lifetime and supply sufficient tritium for deuterium-tritium (DT) fusion driver. This study presents the effect of thickness of flowing liquid wall containing 90 mol % Flibe+10 mol % UF4 or ThF4 on the neutronic performance of a magnetic fusion reactor design called APEX. Neutron transport calculations were carried out with the aid of code Scale4.3. Numerical results brought out that optimum liquid wall thickness of ˜38 cm was found for the blankets using Flibe+10% UF4 whereas, 56 cm for that with Flibe+10% ThF4. Significant amount of high quality fissile fuel was produced by using heavy metal salt.

Übeyli, Mustafa

2006-06-01

215

Performance of intermittent aeration reactor on NH4-N removal from groundwater resources.  

PubMed

To study the effect of intermittent aeration period on ammonium-nitrogen (NH4-N) removal from groundwater resources, synthetic groundwater was prepared and three reactors were operated under different conditions--"reactor A" under continuous aeration, "reactor B" under 6 h intermittent aeration, and "reactor C" under 2 h intermittent aeration. To facilitate denitrification simultaneously with nitrification, "acetate" was added as an external carbon source with step-wise increase from 0.5 to 1.5 C/N ratio, where C stands for total carbon content in the system, and N for NH4-N concentration in the synthetic groundwater. Results show that complete NH4-N removal was obtained in "reactor B" and "reactor C" at 1.3 and 1.5 C/N ratio respectively; and partial NH4-N removal in "reactor A". These results suggest that intermittent aeration at longer interval could enhance the reactor performance on NH4-N removal in terms of efficiency and low external carbon requirement. Because of consumption of internal carbon by the process, less amount of external carbon is required. Further increase in carbon in a form of acetate (1.5 to 2.5 C/N ratios) increases removal rate (represented by reaction rate coefficient (k) of kinetic equation) as well as occurrence of free cells. It suggests that the operating condition at reactor B with 1.3 C/N ratio is more appropriate for long-term operation at a pilot-scale. PMID:20555202

Khanitchaidecha, W; Nakamura, T; Sumino, T; Kazama, F

2010-01-01

216

Fuel performance models for high-temperature gas-cooled reactor core design  

SciTech Connect

Mechanistic fuel performance models are used in high-temperature gas-cooled reactor core design and licensing to predict failure and fission product release. Fuel particles manufactured with defective or missing SiC, IPyC, or fuel dispersion in the buffer fail at a level of less than 5 x 10/sup -4/ fraction. These failed particles primarily release metallic fission products because the OPyC remains intact on 90% of the particles and retains gaseous isotopes. The predicted failure of particles using performance models appears to be conservative relative to operating reactor experience.

Stansfield, O.M.; Simon, W.A.; Baxter, A.M.

1983-09-01

217

Alkaline pretreatment for enhancement of biogas production from banana stem and swine manure by anaerobic codigestion.  

PubMed

The objective of this research was to propose and investigate the availability of digested banana stem (BS) to produce biogas. Squeezed BS with less moisture content was used for biogas production through a combination of NaOH pretreatment, solid-state fermentation, and codigestion technologies. NaOH doses were optimized according to biogas fermentation performance, and the best dose was 6% (by weight) based on the total solid (TS) of BS. Under this condition, the lignin, cellulose, and hemicellulose contents decreased from 18.36%, 32.36% and 14.6% to 17.10%, 30.07%, and 10.65%, respectively, after pretreatment. After biogas digestion, TS and volatile solid (VS) reductions of the codigestion were 48.5% and 70.4%, respectively, and the biogas and methane yields based on VS loading were 357.9 and 232.4mL/g, which were 12.1% and 21.4%, respectively, higher than the control. Results indicated that the proposed process could be an effective method for using BS to produce biogas. PMID:24128397

Zhang, Chengming; Li, Jihong; Liu, Chen; Liu, Xiaoling; Wang, Jianlong; Li, Shizhong; Fan, Guifang; Zhang, Lei

2013-09-27

218

Effect of extracellular enzyme activity on digestion performance of mesophilic UASB reactor treating high-strength municipal wastewater  

Microsoft Academic Search

Effect of extracellular enzyme activity on digestion performance of up-flow anaerobic sludge blanket (UASB) reactor was investigated\\u000a for enhancement of anaerobic treatability of municipal wastewater. Two identical UASB reactors (9 L), namely Reactor-A (without\\u000a enzyme addition) and Reactor-B (with enzyme addition), were simultaneously operated at mesophilic conditions (32 ± 2 °C) with\\u000a a hydraulic retention time of 24 h. Preliminary test results showed that the

F. Ilter Turkdogan-Aydinol; Kaan Yetilmezsoy; Sezen Comez

2011-01-01

219

Performance and fuel cycle cost study of the R2 reactor with HEU and LEU fuels  

SciTech Connect

A systematic study of the experiment performance and fuel cycle costs of the 50 MW R2 reactor operated by Studsvik Energiteknik AB has been performed using the current R2 HEU fuel, a variety of LEU fuel element designs, and two core-box/reflector configurations. The results include the relative performance of both in-core and ex-core experiments, control rod worths, and relative annual fuel cycle costs.

Pond, R.B.; Freese, K.E.; Matos, J.E.

1984-01-01

220

Dry anaerobic digestion in batch mode: design and operation of a laboratory-scale, completely mixed reactor.  

PubMed

A laboratory-scale (40 l) reactor was designed to investigate dry anaerobic digestion. The reactor is equipped with an intermittent paddle mixer, enabling complete mixing in the reactor. Three consecutive batch dry digestion tests of municipal solid waste were performed under mesophilic conditions and compared to operation results obtained on a pilot-scale (21 m(3)) with the same feedstock. Biogas and methane production at the end of the tests were similar (around 200 m(3) CH(4)STP/tVS), and the dynamics of methane production and VFA accumulation concurred. However, the maximal levels of VFA transitory accumulation varied between reactors and between runs in a same reactor. Ammonia levels were similar in both reactors. These results show that the new reactor accurately imitates the conditions found in larger ones. Adaptation of micro-organisms to the waste and operating conditions was also pointed out along the consecutive batches. PMID:20096555

Guendouz, J; Buffière, P; Cacho, J; Carrère, M; Delgenes, J-P

2010-01-21

221

Reactor containment purge and vent valve performance experiments  

Microsoft Academic Search

Three nuclear-designed butterfly valves typical of those used in domestic nuclear power plant containment purge and vent applications were tested. For a comparison of responses, two eight-inch nominal pipe size valves with differing internal design were tested. For extrapolation insights, a 24-inch nominal pipe size valve was also tested. The valve experiments were performed with various piping configurations and valve

J. A. Hunter; R. Steele; J. C. Watkins

1985-01-01

222

Passive solar technology aids biogas digesters  

SciTech Connect

Farming communities throughout China rely on biogas generators as a primary source of light and heat, as well as using the sludge as a nitrogen-rich fertilizer. Now researchers at Beijing's Solar Energy Laboratory have improved efficiency by building a rectangular tank out of concrete slabs, with one slanted surface painted black and covered with glass. According to a report in New Scientist, this passive solar panel generates heat in the same way as a greenhouse, raising inside temperatures by 10{degree}C and increasing biogas production by 50%. Another advantage of the new tanks is easy access, since the tank's lid sites in wells of water which form a seal against oxygen. (Old biogas tanks were made of soil, sand and a little concrete, prone to developing severe cracks which would allow oxygen to enter thus slowing down anaerobic reaction). Explains Debora MacKenzie of New Scientist: with the new tank, the farmer can simply remove the lid and attack the contents with a spade. This means that the mixture can comprise more than 10% solids. Greater density allows smaller tanks. Rural families need one cubic meter of biogas daily for light and heat; instead of the former 8 cm biogas generator, the new tanks need only be 1 cm. The prediction is that the smaller size could make biogas more popular in China's crowded towns. The biogas department is headed by He Shao Qi, who is also investigating ways to reduce production costs for the tanks.

Not Available

1988-07-01

223

FUZZY MODELLING APPLIED TO AN UASB REACTOR  

Microsoft Academic Search

High-rate anaerobic systems, such as the upflow anaerobic sludge blanket (UASB) reactors, are widely used in municipal and industrial wastewater treatment. Even though UASB reactors have several operational advantages, many industries are still reluctant to use them due to the fact that these reactors usually demand constant monitoring of effluent quality, excess sludge discharge and biogas production rate. Otherwise, they

R. M. Borges; C. J. Munaro; R. F. Gonçalves

224

Effect of rapid hydraulic shock loads on the performance of granular bed baffled reactor.  

PubMed

This paper describes the performance of a granular bed baffled reactor when receiving unpredictable hydraulic shock loads, which is a frequent occurrence in industrial wastewater treatment plants. Shock loads were created by rapidly increasing volumetric organic loading rates from 2.5 to 20 kg COD m(-3) d(-1), by decreasing (in a stepwise fashion) hydraulic retention time from 48 hrs to 6 hrs. Synthetic wastewater containing glucose as the main organic compound was used in this study. High effluent quality was observed, with soluble COD removal efficiencies of 94% to 97%, during all shock loading conditions at steady state. The reactor appeared to possess high tolerance to rapid hydraulic changes with fast recovery time. Marked phase separation between different microorganisms occurred at high organic loading rate, with acidogenesis and methanogenesis being the respective dominant activities in the upstream and downstream compartments of the reactor. The compartmentalised nature of the reactor and the granular bed structure were believed to be responsible for high reactor stability during overloading conditions. Microbial ecology in the system appeared to favour acetate and butyrate production at high organic loading rate. Granular biomass possessed good settling characteristics, hence encouraging high biomass retention within the system. The dense granular bed in the methanogenic zone acted as a filtration bed for lighter floating non-granular biomass, thus further reducing overall effluent solids concentration. This study demonstrated that the granular bed baffled reactor is a suitable system for treating industrial wastewaters with highly varying rates. PMID:12703861

Baloch, M I; Akunna, J C

2003-03-01

225

REACTOR  

DOEpatents

A breeder reactor is described, including a mass of fissionable material that is less than critical with respect to unmoderated neutrons and greater than critical with respect to neutrons of average energies substantially greater than thermal, a coolant selected from sodium or sodium--potassium alloys, a control liquid selected from lead or lead--bismuth alloys, and means for varying the quantity of control liquid in the reactor. (AEC)

Szilard, L.

1963-09-10

226

Startup of an anaerobic fluidized bed reactor for landfill leachate treatment.  

PubMed

Anaerobic treatment of the young landfill leachate in a pilot-scale fluidized bed reactor was performed to observe the effects of startup on COD removal, biogas production and biomass attachment. During the experiments, the organic loading rate (OLR) was increased gradually from 2.5 to 27 g COD l(-1) day(-1) with varying the feed rate and the hydraulic retention time in the range of 5.5-13 1 day(-1) and 1-2.35 days, respectively. The anaerobic fluidized bed reactor (AFBR) showed an excellent performance and attained steady state conditions with COD removal of 90% after 80 days. Biogas production in the reactor continuously increased and its average yield (Y(gas)) was defined as 0.531 biogas g(-1) COD(rem)(-1) with a correlation of 99%. Greater microbial attachment was found at the increased loading rates and the attached biomass concentration (X(attach)) consisted of about 90% of the total biomass concentration. In addition, the substrate utilization rate indicated a linear increase as a function of time during the process. PMID:15551824

Gulsen, H; Turan, M

2004-10-01

227

Increasing biogas yield of rural biogas digester by addition of NHâHCOâ  

Microsoft Academic Search

By addition of 0.3% NHâHCOâ instead of animal manure into rural biogas digester in which the rotted rice straw was the major feedstock, the biogas yield doubled in comparison with the check digester (0.1 m³\\/m³\\/d) and the fertility of NHâHCOâ did not decrease because of biogas fermentation. Many digesters have been built in China. But, owing to the problems of

G. C. Sun; G. Q. Chen; M. Chen; K. X. Liu; S. Y. Zhou

1983-01-01

228

Evaluating the biogas potential of the dry fraction from pretreatment of food waste from households.  

PubMed

At the waste handling company NSR, Helsingborg, Sweden, the food waste fraction of source separated municipal solid waste is pretreated to obtain a liquid fraction, which is used for biogas production, and a dry fraction, which is at present incinerated. This pretreatment and separation is performed to remove impurities, however also some of the organic material is removed. The possibility of realising the methane potential of the dry fraction through batch-wise dry anaerobic digestion was investigated. The anaerobic digestion technique used was a two-stage process consisting of a static leach bed reactor and a methane reactor. Treatment of the dry fraction alone and in a mixture with structural material was tested to investigate the effect on the porosity of the leach bed. A tracer experiment was carried out to investigate the liquid flow through the leach beds, and this method proved useful in demonstrating a more homogenous flow through the leach bed when structural material was added. Addition of structural material to the dry fraction was needed to achieve a functional digestion process. A methane yield of 98 m3/ton was obtained from the dry fraction mixed with structural material after 76 days of digestion. This was in the same range as obtained in the laboratory scale biochemical methane potential test, showing that it was possible to extract the organic content in the dry fraction in this type of dry digestion system for the production of methane. PMID:23465311

Murto, Marika; Björnsson, Lovisa; Rosqvist, Håkan; Bohn, Irene

2013-03-07

229

Trends versus reactor size of passive reactivity shutdown and control performance  

Microsoft Academic Search

Favorable passive reactivity shutdown performance in response to unprotected accident initiators has been shown to be achievable when several measurable, integral reactivity parameters related to the power, flow, and inlet temperature coefficients of reactivity satisfy certain simple constraints among their dimensionless ratios. The trends in these dimensionless ratios with reactor size for both oxide- and metal-fueled cores have been developed,

D. C. Wade; E. K. Fujita

1989-01-01

230

DEVELOPMENT OF AN INTEGRATED PERFORMANCE MODEL FOR TRISO-COATED GAS REACTOR PARTICLE FUEL  

Microsoft Academic Search

The success of gas reactors depends upon the safety and quality of the coated particle fuel. The understanding and evaluation of this fuel requires development of an integrated mechanistic fuel performance model that fully describes the mechanical and physico- chemical behavior of the fuel particle under irradiation. Such a model, called PARFUME (PARticle FUel ModEl), is being developed at the

G. K. MILLER; D. A. PETTI; J. T. MAKI

231

Influence of total solid and inoculum contents on performance of anaerobic reactors treating food waste  

Microsoft Academic Search

The aim of this paper was to analyze the biomethanization process of food waste (FW) from a university campus restaurant in six reactors with three different total solid percentages (20%, 25% and 30% TS) and two different inoculum percentages (20–30% of mesophilic sludge). The experimental procedure was programmed to select the initial performance parameters (total solid and inoculum contents) in

T. Forster-Carneiro; M. Pérez; L. I. Romero

2008-01-01

232

Assessment of confinement performance and consequences for severe accidents at the High-Flux Beam Reactor  

Microsoft Academic Search

A level 2 and 3 probabilistic risk assessment for accidents initiated by internal events at the High-Flux Beam Reactor (HFBR) has been performed. These analyses followed by the level 2 analyses for internal events. The level 1 analyses provided frequencies for certain modes of failure that are expected to lead to core damage. The level 2 analyses studied the accident

A. L. Hanson; W. T. Pratt

1991-01-01

233

Modelling the effects of enzyme activation on the performance of packed?bed biological reactor  

Microsoft Academic Search

The performance of packed bed reactor has been analysed by considering diffusional resistance of the biofilm. The model equations have been solved by the method of orthogonal collocation from the transient to steady state conditions for various classical enzyme activation kinetics. For all the models of activation considered, an increase in the inlet substrate concentration decrease the steady state conversion

S. A. Beg; M. M. Hassan; N. A. Jamal

1993-01-01

234

Reactor physics support to the study of fuel performance and plutonium recycle in Sena  

Microsoft Academic Search

Since its start the Belgian plutonium recycling physics program has ; shown a particular interest for the case of the SENA reactor. This was clearly ; reflected by the choice of the geometrical and fuel composition characteristics ; of the VENUS critical facility in which the plutonium recycling studies have been ; carried out. After a large basic program performed

J. Debrue; L. Leenders; F. Motte; H. van den Broeck

1973-01-01

235

Calculated performance of various structural materials in fusion-reactor blankets  

Microsoft Academic Search

The calculated nuclear performances of niobium, SS-304, and nimonic-105 ; as structural materials in a conceptual D-T fusion-reactor blanket model are ; compared. For each structural material, the tritium breeding ratio, the energy-; deposition rate, the operating dose, the time dependence of the neutron-induced ; activity, the time dependence of the dose from the activation products, the time ; dependence

M. L. Williams; R. T. Santoro; T. A. Gabriel

1975-01-01

236

Polonium decontamination performance of stainless steel mesh filter for lead alloy-cooled reactors  

Microsoft Academic Search

Lead–Bismuth eutectic (LBE) has many good characteristics as a coolant for fast reactors. One of the issues remaining to be solved, however, is the polonium issue. The purpose of the present study was to estimate the decontamination performance of a polonium filter by experiment in the penetration condition. Two types of stainless steel wire meshes, fine wire mesh and loose

Toru Obara; Yu Yamazawa; Toshinobu Sasa

2011-01-01

237

AN IN-PILE LOOP STUDY OF THE PERFORMANCE OF POLYPHENYL REACTOR COOLANTS  

Microsoft Academic Search

An in-pile loop experiment was performed to evaluate several promising ; polyphenyl materials for use as reactor moderator coolants. Isopropyl diphenyl, ; diphenyl, a mixture of Santowax O and Santowax M, and Santowax R were circulated ; in an in-pile loop containing a uranium heater, at bulk fluid temperatures of 500 ; to 700 F and at fluid velocities of

Bley

1958-01-01

238

Enhanced treatment of wastewater from the vitamin C biosynthesis industry using a UASB reactor supplemented with zero-valent iron  

Microsoft Academic Search

The effects of zero-valent iron (Fe) on the performance of a mesophilic upflow anaerobic sludge blanket (UASB) reactor treating high-strength wastewater from the vitamin C biosynthesis industry (VCW) was investigated during a 200-day period. The results showed that the chemical oxygen demand (COD) removal efficiency, CH4 content in biogas, specific methanogenic activity of sludge, and phosphate removal efficiency were significantly

Rongjiu Shi; Hui Xu; Ying Zhang

2011-01-01

239

Irradiation performance of metallic driver fuel in Experimental Breeder Reactor II to high burnup  

Microsoft Academic Search

The Experimental Breeder Reactor II Mark-II metallic-driver-fuel element has been irradiated to high burnup to assess element lifetime and performance reliability. The purpose of this paper is to describe the irradiation performance of the Mark-II fuel element to 10 at.% burnup. Fission gas behavior, fuel deformation, fuel-cladding chemical interaction, fuel-cladding mechanical interaction, and cladding dilation are examined for their effect

R. E. Einziger; B. R. Seidel

1980-01-01

240

REACTOR  

DOEpatents

A pressurized water reactor in which automatic control is achieved by varying the average density of the liquid moderator-cooiant is patented. Density is controlled by the temperature and power level of the reactor ftself. This control can be effected by the use of either plate, pellet, or tubular fuel elements. The fuel elements are disposed between upper and lower coolant plenum chambers and are designed to permit unrestricted coolant flow. The control chamber has an inlet opening communicating with the lower coolant plenum chamber and a restricted vapor vent communicating with the upper coolant plenum chamber. Thus, a variation in temperature of the fuel elements will cause a variation in the average moderator density in the chamber which directly affects the power level of the reactor.

Roman, W.G.

1961-06-27

241

The Use of Gas Chromatography for Biogas Analysis  

NASA Astrophysics Data System (ADS)

Energy from natural gas accounts for 24 percent of energy consumed in the US. Natural gas is a robust form of energy which is rich in methane content and is low in impurities. This quality suggests that it is a very clean and safe gas; it can be used in providing heat, a source for cooking, and in powering vehicles. The downside is that it is a non-renewable resource. On the contrary, methane rich gas that is produced by the breakdown of organic material in an anaerobic environment, called biogas, is a renewable energy source. This research focuses on the gas analysis portion of the creation of the anaerobic digestion and verification laboratory where content and forensic analysis of biogas is performed. Gas Chromatography is implemented as the optimal analytical tool for quantifying the components of the biogas including methane, carbon dioxide, hydrogen sulfide and siloxanes. In addition, the problems associated with the undesirable components are discussed. Anaerobic digestion of primary sludge has consistently produced about 55 percent methane; future goals of this research include studying different substrates to increase the methane yield and decrease levels of impurities in the gas.

Andersen, Amanda; Seeley, John; Aurandt, Jennifer

2010-04-01

242

Biogas/Biofertilizer Business Handbook (Third Edition).  

National Technical Information Service (NTIS)

The handbook covers biogas systems, including raw material preparation, digesters, separate gas storage tanks, use of gas to run engines, and the use of sludge as fertilizer. Also covers secondary projects such as flat-plate solar collector water heaters,...

M. Arnott

1985-01-01

243

Biogas Workshop on Community Plants. Report.  

National Technical Information Service (NTIS)

Resulting from an exchange and comparison of experiences, the workshop firmly stated that success will not be achieved if governments do not provide a political, organizational and economic framework, thus making biogas technology a tool in development pr...

1984-01-01

244

Introduction to Biogas Production on the Farm.  

National Technical Information Service (NTIS)

A number of farmers, ranchers, and engineers received support from the US Department of Energy Appropriate Technology Small Grants Program to design, construct, and demonstrate biogas production systems. Many of these projects generated more than just bio...

1984-01-01

245

Biogas development in India and the PRC  

SciTech Connect

A comparison of biogas development and use in India and China shows that 0.1% of the Indian population compared with 3.8% of the Chinese population uses biogas. The authors identify the critical aspects of biogas technology development and its successful diffusion on the basis of the experiences of these two countries. They conclude that prevailing social, economic, technical, and cultural imperatives limit technology diffusion in a society. Biogas technology in India primarily meets the domestic needs of rural families, while China's application to power generation and industrial production has been more economically viable. Family-size plants will only be viable if they are designed to integrate use points and expand uses beyond cooking to irrigation, lighting, or other commercial purposes. 29 references, 3 tables.

Kharbanda, V.P.; Qureshi, M.A.

1985-07-01

246

Cogeneration of electricity and heat from biogas  

SciTech Connect

Biogas production from animal manures is becoming more well defined and popular. The ultimate value of the production of biogas by anaerobic digestion depends on the extent to which existing farm fuels can be replaced. The goal of this study was to document at full scale biogas conversion to electricity and heat energy in a custom-designed cogeneration internal combustion engine facility. The digesters continued to process cow manure without problems, achieving greater than 80% conversion of the biodegradable organics under most conditions. The plug flow unit continued to be a simpler and more efficient system than the completely mixed alternative. Eight loading conditions were documented. Attention was focused on engine wear and maintenance problems associated with biogas use. Extensive monitoring and testing of lubrication oil was conducted. 61 refs., 61 figs., 19 tabs.

Jewell, W.J.; Koelsch, R.K.; Cummings, R.J.

1986-03-01

247

New strategies for biogas recovery  

SciTech Connect

Programs to encourage use of biogas produced both at wastewater plants with anaerobic digesters and at landfills, through natural decomposition processes, were initiated in 1980 by New York States Energy Office Bureau of Resource Development. Fifteen prime landfill sites with commercial prospects have been identified in New York State, and the advantages, disadvantages and economics of these are discussed. New regulations on landfill gas migration control may justify the economics of a recovery program at some sites. The wastewater program has been developed to both optimize potential energy production and to reduce energy consumption- eleven wastewater plants have been selected for an in-depth study on ways to use presently wasted digester gas. (Refs. 9).

Bogardus, E.R.

1981-09-01

248

Biomass loss from an anaerobic fluidized bed reactor  

Microsoft Academic Search

The phenomena of biomass loss during reactor startup and steady-state operation of an anaerobic fluidized bed (AFB) reactor using porous media particles and fed with acetic acid are studied. The amount of biomass lost during reactor startup is found to be correlated to both substrate utilization and biogas production. However, the level of biomass lost does not impede reactor startup

Wen K. Shieh; Yen Hsu

1996-01-01

249

Biogas aus Festmist - eine neue Technologie zu Schließung des Nährstoff- und Energiekreislaufes auf dem landwirtschaftlichen Betrieb Biogas from manure - a new technology to close the nutrient and energy circuit on-farm  

Microsoft Academic Search

The Biodynamic Research Institute in Järna developed at the farm Yttereneby a two phase biogas plant. The plant digests manure of dairy cattle and organic residues originating from the farm and the surrounding food processing units containing 17,7 - 19,6 % dry matter. A new technology for continuously filling and discharging the bio- gas reactor was developed and implemented. Digestion

W. Schäfer; L. Evers; M. Lehto; S. Sorvala; F. Teye; A. Granstedt

250

The development of biogas technology in India  

NASA Astrophysics Data System (ADS)

Biogas from organic wastes is a potential renewable energy to meet the domestic energy needs in India. The fundamentals of bio-gasification by anaerobic digestion are presented. The production of biogas from cattle manure in small anaerobic digesters is discussed, illustrated by a popular digester model. The need for the development of community digesters for the needs of a village and its implications are mentioned. The research work on biogasification at Andhra University is summarized.

Chiranjivi, C.; Raviprasad, A.; Rao, K. V.

251

Thorium Fuel Performance in a Tight-Pitch Light Water Reactor Lattice  

SciTech Connect

Research on the utilization of thorium-based fuels in the intermediate neutron spectrum of a tight-pitch light water reactor (LWR) lattice is reported. The analysis was performed using the Studsvik/Scandpower lattice physics code HELIOS. The results show that thorium-based fuels in the intermediate spectrum of tight-pitch LWRs have considerable advantages in terms of conversion ratio, reactivity control, nonproliferation characteristics, and a reduced production of long-lived radiotoxic wastes. Because of the high conversion ratio of thorium-based fuels in intermediate spectrum reactors, the total fissile inventory required to achieve a given fuel burnup is only 11 to 17% higher than that of {sup 238}U fertile fuels. However, unlike {sup 238}U fertile fuels, the void reactivity coefficient with thorium-based fuels is negative in an intermediate spectrum reactor. This provides motivation for replacing {sup 238}U with {sup 232}Th in advanced high-conversion intermediate spectrum LWRs, such as the reduced-moderator reactor or the supercritical reactor.

Kim, Taek Kyum; Downar, Thomas J. [Purdue University (United States)

2002-04-15

252

Pathogenic bacteria and mineral N in soils following the land spreading of biogas digestates and fresh manure  

Microsoft Academic Search

The on-farm production of renewable energy from animal manures has rapidly expanded in central and northern Europe, with thousands of anaerobic reactors. This process has increased the land spreading of biogas digestates, replacing the use of fresh manure as a fertiliser. The environmental benefits and risks of such a change still need to be defined. We hypothesised that applying to

M. Goberna; S. M. Podmirseg; S. Waldhuber; B. A. Knapp; C. García; H. Insam

2011-01-01

253

Svavel- och koldioxidrening av biogas. (Sulphur and carbon dioxide purification of biogas).  

National Technical Information Service (NTIS)

The purpose was to compile and describe existing techniques of separating hydrogen sulphide and carbon dioxide from biogas, and to make a technical and economic assessment of their potentials. The main components in biogas are methane, CH(sub 4), and carb...

A. Lindberg

1992-01-01

254

Feeding approaches for biogas production from animal wastes and industrial effluents  

Microsoft Academic Search

Different feeding approaches were applied to a 5 l anaerobic digester in order to improve the biogas production. During operation, the reactor was fed with a mixture (9.7% w\\/v total solids (TS) and 7.6% w\\/v volatile solids (VS) in average) of pig manure with fish oil waste and waste from bentonite of edible oil filtration process, at different intervals of

A. P. Francese; G. Aboagye-Mathiesen; T. Olesen; P. R. Córdoba; F. Siñeriz

2000-01-01

255

Strategies for optimizing recovery of the biogas process following ammonia inhibition  

Microsoft Academic Search

Strategies for recovery of ammonia-inhibited thermophilic biogas process, were evaluated in batch and lab-scale reactors. Active methane producing biomass (digested cattle manure) was inhibited with NH4Cl and subsequently, 3–5 days later, diluted with 50% of water, or with 50% digested manure, or with 50% fresh manure or kept undiluted. Dilution with fresh cattle manure resulted in the highest methane production

Henrik Bangsø Nielsen; Irini Angelidaki

2008-01-01

256

Production of biogas from water hyacinth (Eichhornia crassipes) (Mart) (Solms) in a two-stage bioreactor  

Microsoft Academic Search

A two-stage rumen-derived anaerobic digestion process was tested for the conversion of water hyacinth shoots and a mixture of the shoots with cowdung (7:3) into biogas. Under conditions similar to those of the rumen and loading rates (LR) in the range of 11.6–19.3g volatile solids (VS) l-1d-1 in the rumen reactor, the degradation efficiencies were 38% for the shoots and

A. K. Kivaisi; M. Mtila

1998-01-01

257

Growth kinetics of thermophilic Methanosarcina spp. isolated from full-scale biogas plants treating animal manures  

Microsoft Academic Search

This study determines the growth kinetics of thermophilic strains of Methanosarcina spp. from full-scale thermophilic biogas plants. The complete set of kinetic parameters, including maximum specific growth rate ?max, half saturation constant KS, acetate threshold concentration and cell growth yield YX\\/S, were determined for six Methanosarcina strains newly isolated from full-scale reactors and the type strain Methanosarcina thermophila TM-1T. The

Zuzana Mladenovska; Birgitte Kiær Ahring

2000-01-01

258

Fuel density, uranium enrichment, and performance studies for the Advanced Neutron Source reactor  

SciTech Connect

Consistent with the words of the budget request for the Advanced Neutron Source (ANS), DOE commissioned a study of the impact on performance of using medium- or low-enriched uranium (MEU or LEU) in the fuel of the reactor that generates the neutrons. In the course of the study, performance calculations for 19 different combinations of reactor core volume, fuel density and enrichment, power level, and other relevant parameters were carried out. Since then, another 14 cases have been analyzed at Oak Ridge to explore some of the more interesting and important configurations and to gain further insights into the tradeoffs between performance and enrichment. Furthermore, with the aid of the data from these additional cases, we have been able to correlate the most important performance parameters (peak thermal neutron flux in the reflector and core life) with reactor power, fuel density, and fuel enrichment. This enables us to investigate intermediate cases, or alternative cases that might be proposed by people within or outside the project, without the time and expense of doing completely new neutronics calculations for each new example. The main drivers of construction and operating costs are the reactor power level and the number of fuel plates to be fabricated each year; these quantities can be calculated from the correlations. The results show that the baseline two-element core design cannot be adapted to any practical fuel of greatly reduced enrichment without great performance penalties, but that a modification of the design, in which one additional fuel element is incorporated to provide extra volume for lower enrichment fuels, has the capability of using existing, or more advanced, fuel types to lower the uranium enrichment.

Alston, E.E.; Gehin, J.C.; West, C.D.

1994-06-01

259

REACTOR  

DOEpatents

The system conteraplates ohmically heating a gas to high temperatures such as are useful in thermonuclear reactors of the stellarator class. To this end the gas is ionized and an electric current is applied to the ionized gas ohmically to heat the gas while the ionized gas is confined to a central portion of a reaction chamber. Additionally, means are provided for pumping impurities from the gas and for further heating the gas. (AEC)

Spitzer, L. Jr.

1962-01-01

260

Comparative study on safety performance of nitride fueled lead-bismuth cooled fast reactor with various power levels  

Microsoft Academic Search

In the present study safety performance of nitride fueled lead-bismuth cooled fast reactors of several sizes (150 MWt ? 2500 MWt) but all having maximum burn-up of about 9?11 % HM are evaluated and compared. Small reactors can be operated up to 12 years, and large reactors(2500MWt) can be operated up to about 4 years without refueling or fuel shuffling.

Zaki Su'ud

1998-01-01

261

Decay heat of sodium fast reactor: Comparison of experimental measurements on the PHENIX reactor with calculations performed with the French DARWIN package  

SciTech Connect

A Decay Heat (DH) experiment on the whole core of the French Sodium-Cooled Fast Reactor PHENIX has been conducted in May 2008. The measurements began an hour and a half after the shutdown of the reactor and lasted twelve days. It is one of the experiments used for the experimental validation of the depletion code DARWIN thereby confirming the excellent performance of the aforementioned code. Discrepancies between measured and calculated decay heat do not exceed 8%. (authors)

Benoit, J. C.; Bourdot, P.; Eschbach, R.; Boucher, L.; Pascal, V.; Fontaine, B.; Martin, L.; Serot, O. [CEA, DEN, DER, F-13108 ST Paul-Lez-Durance (France)

2012-07-01

262

Hydrodynamic effects on the performance of an electrochemical reactor for destruction of copper cyanide. Part 2—reactor kinetics and current efficiencies  

Microsoft Academic Search

An electrochemical reactor, with stainless-steel electrodes, was used for treatment of a wastewater containing dilute copper(I) cyanide. Both anodic cyanide oxidation and cathodic copper(I) reduction could be operated under mass transport control, when reactions rates and current efficiencies were influenced by hydrodynamic conditions created by pumping and gas sparging, used to enhance reactor performance. Pumping promoted the rate of Cu

Lidia Szpyrkowicz; Geoffrey H. Kelsall; Ricardo M. Souto; Francesco Ricci; Santosh N. Kaul

2005-01-01

263

A numerical performance study of the PGCR method applied to nuclear reactor heat transfer calculations  

Microsoft Academic Search

This paper discusses the preconditioned generalized conjugate residual (PGCR) method an iterative method used in the integrated systems code (ISC) to simulate heat transfer in a modular high-temperature gas-cooled reactor. In this paper the numerical performance of the PGCR method is assessed to determine the computational requirements of the ISC. A steady-state heat transfer problem that includes conduction, convection, advection,

1992-01-01

264

Irradiation Performance of Fast Reactor MOX Fuel Assemblies Irradiated to High Burnups  

Microsoft Academic Search

Mixed oxide fuel assemblies (MFA-1 and MFA-2 assemblies) were irradiated in the fast flux test facility to evaluate the irradiation performance of fast reactor core fuels at high burnups and high fast neutron fluences. The MFA-1 and MFA-2 assemblies achieved respective peak pellet burnups of 147 and 162GWd\\/t, and resisted to respective peak fast neutron fluences (E > 0:1 MeV)

Tomoyuki UWABA; Masahiro ITO; Tomoyasu MIZUNO

2008-01-01

265

Calculated performance of various structural materials in fusion-reactor blankets  

Microsoft Academic Search

The calculated nuclear performances of niobium, Type 304 stainless steel, and nimonic-105 as structural materials in a conceptual D-T fusion-reactor blanket model are compared. For each structural material, the tritium breeding ratio, the energy-deposition rate, the operating dose, the time dependence of the neutron-induced activity, the time dependence of the dose from the activation products, the time dependence of the

M. L. Williams; R. T. Santoro; T. A. Gabriel

1976-01-01

266

Design and operation of small biogas plants  

SciTech Connect

This paper concentrates on the experience gained from the adaptation of the Chinese biogas technology to rural areas of Egypt. Three different prototype digesters have been constructed. The first is a 10 M/sup 3/ rectangular digester of the water pressure type, the second is a 6 M/sup 3/ circular and shallow digester with domed roof and dished bottom. The third prototype unit with a capacity of 7 M/sup 3/ has been recently constructed. It combines the features of both plug flow and the Indian movable cap types. Provisions for solar heating of feed water, composting of effluent and attachments to both latrine and animal shed were incorporated in the unit. The structural theory, design criteria, construction technique and cost estimation of the circular digester are described. Some operation and performance data of the circular digester are presented. This covers the effects of variation of ambient temperature on internal temperature, effects of temperature and pressure on the gas production rate and composition.

Abdel-Dayem, A.M.; Hamad, M.A.

1980-12-01

267

Compressed biogas at the Christchurch Drainage Board. Final report  

SciTech Connect

Experience of the Christchurch Drainage Board in using biogas for fueling a part of its transport fleet is described. The experience is documented and benefits to other potential users of biogas are demonstrated.

Not Available

1986-04-01

268

Mixed Uranium/Refractory Metal Carbide Fuels for High Performance Nuclear Reactors  

SciTech Connect

Single phase, solid-solution mixed uranium/refractory metal carbides have been proposed as an advanced nuclear fuel for advanced, high-performance reactors. Earlier studies of mixed carbides focused on uranium and either thorium or plutonium as a fuel for fast breeder reactors enabling shorter doubling owing to the greater fissile atom density. However, the mixed uranium/refractory carbides such as (U, Zr, Nb)C have a lower uranium densities but hold significant promise because of their ultra-high melting points (typically greater than 3700 K), improved material compatibility, and high thermal conductivity approaching that of the metal. Various compositions of (U, Zr, Nb)C were processed with 5% and 10% metal mole fraction of uranium. Stoichiometric samples were processed from the constituent carbide powders, while hypo-stoichiometric samples with carbon-to-metal (C/M) ratios of 0.92 were processed from uranium hydride, graphite, and constituent refractory carbide powders. Processing techniques of cold uniaxial pressing, dynamic magnetic compaction, sintering, and hot pressing were investigated to optimize the processing parameters necessary to produce high density (low porosity), single phase, solid-solution mixed carbide nuclear fuels for testing. This investigation was undertaken to evaluate and characterize the performance of these mixed uranium/refractory metal carbides for high performance, ultra-safe nuclear reactor applications. (authors)

Knight, Travis; Anghaie, Samim [Innovative Nuclear Space Power and Propulsion Institute (INSPI), PO Box 116502, University of Florida, Gainesville, FL 32611-6502 (United States)

2002-07-01

269

Performance of the ANAMMOX process using multi- and single-fed upflow anaerobic sludge blanket reactors.  

PubMed

The performance of the ANAMMOX process was investigated in two identical laboratory-scale multi- and single-fed upflow anaerobic sludge blanket (UASB) reactors (denoted R1 and R0) at different hydraulic residence times (HRTs) varying from 2.06 to 1.52h and NH4(+)-Ninf concentrations ranging from 70 to 266mgL(-1). The substrate removal efficiencies of both reactors decreased as HRT decreased and NH4(+)-Ninf increased. The kinetics of these reactions were analyzed, and the Stover-Kincannon model was appropriate to describe the process kinetics of the reactors. In addition, an empirical model incorporating the influent substrate concentration and HRT adequately described R1. Shock experiments were conducted in which the reactors were subjected to transient shock loads. The results showed that the operation of R1 was more stable than that of R0, especially in response to the substrate shocks. Subsequently, the properties of the ANAMMOX granules and the effects of the feeding protocol on those properties were investigated. PMID:24121373

Xing, Bao-Shan; Qin, Tian-Yue; Chen, Shen-Xing; Zhang, Jue; Guo, Li-Xin; Jin, Ren-Cun

2013-09-27

270

Separation of Biogas Components with Single Wall Carbon Nanotubes: a GCMC Simulation.  

PubMed

Biogas is a green energy source that mainly contains CH4, CO2 ,traces of H2S and fractions of H2O vapor. One of the effective methods in biogas treatment from its pollutants is adsorptive separation. Here, enrichment of methane using (10, 10) and (6, 6) carbon nanotubes (CNTs) in modelled biogas consisting CH4, CO2 and H2S is studied. Simulations were carried out using Grand Canonical Monte Carlo (GCMC) method. Adsorption isotherms obtained at various temperatures and pressures for two single wall carbon nanotubes (SWCNTs). To quantify the separation ability of the nanotubes the adsorptive separation factors for H2S/CH4 and CO2/CH4 were calculated. For studding temperature effect, simulations at two (0.1 and 1 MPa) pressures and four temperatures: 288, 298, 318 and 338 K have been performed. In all studied conditions, CO2 is preferentially adsorbed by CNTs. Results have shown that the two separation factors are considerable, particularly for (10, 10) CNT. Additionally, the adsorption and selectivity behaviour of studied gases were considered in (6,6), (8,8) and (10,10) CNT hexagonal bundles for comparison. The results for single nanotubes were confirmed with the bundles. Hence, despite lower concentration of CO2 than CH4 and trace amount of H2S in biogas, they can be separated from methane effectively by CNTs as adsorbents. Our results showed that the CNTs can be remarkable tools in methane separation from biogas. PMID:24061372

Yeganegi, Saeid; Gholampour, Fatemeh

2012-12-01

271

Anaerobic bioconversion of organic waste into biogas by hot water treatment at near-critical conditions: application in bioregenerative life support.  

PubMed

The feasibility of nearly-complete conversion of lignocellulosic waste (70% food crops, 20% faecal matter and 10% green algae) into biogas was investigated in the context of a Life Support Project. The treatment comprised a series of processes, i.e. a mesophilic laboratory scale CSTR (continuously stirred tank reactor), an upflow biofilm reactor and a hydrothermolysis system in near-critical water. By the one-stage CSTR, a biogas yield of 75% with a specific biogas production of 0.37 l biogas g(-1) VSS (volatile suspended solids) added at a HRT (hydraulic retention time) of 20 d was obtained. Biogas yields further increased with 10-15% at HRT > 20 d, indicating the hydrolysis of lignocellulose to be the rate-limiting conversion step. The solids present in the CSTR-effluent were subsequently treated by hot water treatment (T approximately 310-350 degrees C, p approximately 240 bar), resulting in effective carbon liquefaction (50-60% without and 83% with carbon dioxide saturation) and complete hygienisation of the residue. Subsequent anaerobic digestion of the hydrolysate allowed further conversion of 48-60% on COD (chemical oxygen demand) basis. Thus, the total process yielded biogas corresponding with a COD conversion up to 90% of the original organic matter. It appears that mesophilic digestion in conjunction with hydrothermolysis at near-critical conditions offers interesting features for (nearly) complete, non-toxic and hygienic carbon and energy recovery from human waste in a bioregenerative life support context. PMID:15296155

Lissens, Geert; Verstraete, Willy; Albrecht, Tobias; Brunner, Gerd; Lasseur, Christophe

2003-01-01

272

Biogas cleans up its act  

SciTech Connect

The development of waste-composting facilities and anaerobic waste-treatment plants, which produce smaller volumes of cleaner gas than landfills, has caused companies to reexamine how methane-rich offgas streams are handled. Now, biogas producers are beginning to extract further value from the methane, mainly by cleaning the gas to allow it to be fed to the growing natural-gas grids in the US and Europe. Another value-added route is to clean and boost the gas pressure to 250 bars for use as a fuel in compressed natural gas (CNG) vehicles. Depending on the volume and concentration of contaminants, absorption, carbon adsorption, biofilters, membrane separation, iron-based scavengers and wet oxidation are the principal clean-up routes being pursued. For high flowrates and sulfur loadings in excess o 500 lb/d, liquid oxidation or scavenger-based schemes are the most economic approaches. For lower volumes, however, liquid scrubbing, carbon adsorption and biofilters are more promising. These systems are discussed.

Fouhy, K.; Shelley, S.

1997-05-01

273

Net energy production and emissions mitigation of domestic wastewater treatment system: A comparison of different biogas-sludge use alternatives.  

PubMed

Wastewater treatment systems are increasingly designed for the recovery of valuable chemicals and energy in addition to waste stream disposal. Herein, the life-cycle energy production and emissions mitigation of a typical domestic wastewater treatment system were assessed, in which different combinations of biogas use and sludge processing lines for industrial or household applications were considered. The results suggested that the reuse of biogas and sludge was so important in the system's overall energy balance and environmental performance that it may offset the cost in the plant's installation and operation. Combined heat and power and household utilization were two prior options for net energy production, provided an ideal power conversion efficiency and biogas production. The joint application of household biogas use and sludge nutrient processing achieved both high net energy production and significant environmental remediation across all impact categories, representing the optimal tradeoff for domestic wastewater treatment. PMID:23880131

Chen, Shaoqing; Chen, Bin

2013-07-05

274

Performance of the gas turbine-modular helium reactor fuelled with different types of fertile TRISO particles  

Microsoft Academic Search

Preliminary studies have been performed on operation of the gas turbine-modular helium reactor (GT-MHR) with a thorium based fuel. The major options for a thorium fuel are a mixture with light water reactors spent fuel, mixture with military plutonium or with with fissile isotopes of uranium. Consequently, we assumed three models of the fuel containing a mixture of thorium with

Alberto Talamo; Waclaw Gudowski

2005-01-01

275

Coal liquefaction. Investigation of reactor performance, role of catalysts and PCT properties. Quarterly progress report, April 1June 30, 1986  

Microsoft Academic Search

The objective of this work is to investigate areas of science and technology that have been defined as being of prime interest to coal processing technology development. These areas include properties of coal liquids and slurries, reactor design and performance in relation to reaction mechanisms. The work comprises investigations of the following high priority areas: (1) reaction kinetics and reactor

Y. T. Shah; J. W. Tierney; I. Wender; S. Joseph; C. S. Wen

1986-01-01

276

Biogas as a Renewable Energy Source—A Review  

Microsoft Academic Search

This article reviews the production processes and characterization of biogas as an alternative energy source. Biogas, the gas generated from organic digestion under anaerobic conditions by mixed population of microorganisms, is an alternative energy source, which has been commenced to be utilized both in rural and industrial areas at least since 1958. Biogas technology offers a very attractive route to

M. Balat; H. Balat

2009-01-01

277

Biogas curriculum: workshop, April 6-11, 1981  

Microsoft Academic Search

This report is a curriculum guide for those interested in biogas technology. Its purpose is to develop an understanding of the science, engineering, economics, and environmental implications of the biogas technology. The purpose of the training is to encourage application of biogas process design in the US on a small scale to utilize local supplies of indigenous alternate energy sources

Highnote

1981-01-01

278

Intelligent Fuzzy Control for Biogas in Hydrophobic Polymer System  

Microsoft Academic Search

In this paper, intelligent Fuzzy control system has been applied for biogas processes in a hydrophobic permeable polymer that is proposed to be used in landfills as a medium for biogas collection. Once having experimental information about biogas transport in the polymer within different variables, the information could be modeled by fuzzy system. When fuzzy controller is built with its

Qasaimeh Ahmad; Elektorowicz Maria; J. Iwona

2006-01-01

279

Biogas digesters in the Peoples Republic of China  

Microsoft Academic Search

This paper is a report on the use of biogas in China. The authors traveled in China from May 8 to June 12, 1982 during which time they visited several institutes doing research on biogas and many communes where biogas was produced and used. About 7,000,000 digesters are in actual use in China almost all of which are the small

J. B. Liljedahl; J. Butler; J. S. Caldwell; W. E. Tyner

1983-01-01

280

Feasibility study of utilizing biogas from urban waste  

Microsoft Academic Search

This paper investigates the possibility of utilizing household generated biomass as a source of renewable energy to meet partial energy demand in the urban household in Bangladesh. The work proposes utilization of biogas generated by anaerobic digestion from urban waste using a small scale biogas digester. Three different systems that use biogas for operation, namely — gas operated light bulbs,

Asif Ahsan; Shahriar Ahmed Chowdhury

2012-01-01

281

Biogas Situation and Development in Thai Swine Farm  

Microsoft Academic Search

The biogas technology in Thailand has been developed and adopted for many years, especially in the swine farm industry. The objectives of the biogas development are based on three main problems; i.e. (i) to reduce the appalling odor, (ii) to treat the wastewater, (iii) and to produce the biogas which is known as a renewable energy sources from the anaerobic

Wongkot Wongsapai; Poon Thienburanathum; Prasert Rerkkriengkrai

282

Modeling and performance of the MHTGR (Modular High-Temperature Gas-Cooled Reactor) reactor cavity cooling system  

Microsoft Academic Search

The Reactor Cavity Cooling System (RCCS) of the Modular High- Temperature Gas-Cooled Reactor (MHTGR) proposed by the U.S. Department of Energy is designed to remove the nuclear afterheat passively in the event that neither the heat transport system nor the shutdown cooling circulator subsystem is available. A computer dynamic simulation for the physical and mathematical modeling of and RCCS is

Conklin

1990-01-01

283

Comparison of different procedures to stabilize biogas formation after process failure in a thermophilic waste digestion system: influence of aggregate formation on process stability.  

PubMed

Following a process failure in a full-scale biogas reactor, different counter measures were undertaken to stabilize the process of biogas formation, including the reduction of the organic loading rate, the addition of sodium hydroxide (NaOH), and the introduction of calcium oxide (CaO). Corresponding to the results of the process recovery in the full-scale digester, laboratory experiments showed that CaO was more capable of stabilizing the process than NaOH. While both additives were able to raise the pH to a neutral milieu (pH>7.0), the formation of aggregates was observed particularly when CaO was used as the additive. Scanning electron microscopy investigations revealed calcium phosphate compounds in the core of the aggregates. Phosphate seemed to be released by phosphorus-accumulating organisms, when volatile fatty acids accumulated. The calcium, which was charged by the CaO addition, formed insoluble salts with long chain fatty acids, and caused the precipitation of calcium phosphate compounds. These aggregates were surrounded by a white layer of carbon rich organic matter, probably consisting of volatile fatty acids. Thus, during the process recovery with CaO, the decrease in the amount of accumulated acids in the liquid phase was likely enabled by (1) the formation of insoluble calcium salts with long chain fatty acids, (2) the adsorption of volatile fatty acids by the precipitates, (3) the acid uptake by phosphorus-accumulating organisms and (4) the degradation of volatile fatty acids in the aggregates. Furthermore, this mechanism enabled a stable process performance after re-activation of biogas production. In contrast, during the counter measure with NaOH aggregate formation was only minor resulting in a rapid process failure subsequent the increase of the organic loading rate. PMID:22405750

Kleyböcker, A; Liebrich, M; Kasina, M; Kraume, M; Wittmaier, M; Würdemann, H

2012-03-08

284

Model-based predictions of anaerobic digestion of agricultural substrates for biogas production.  

PubMed

A modified Anaerobic Digestion Model No. 1 (ADM1), calibrated on a laboratory digester with a feeding mix of 30% weight of cow manure and 70% weight of corn silage, was implemented, showing its performances of simulation as a decision-making and planning-supporting tool for the anaerobic digestion of agricultural substrates. The virtual fermenter obtained was used to conduct simulations with different feeding compositions and loading rates of cow manure, corn silage, grass silage and rape oil. All simulations were started at the same initial state which was represented by a steady state with an organic loading rate of 2.5 kg ODM/(mdigester3?d). The effects of the different feeding combinations on biogas composition and biogas yield were predicted reasonably, and partly verified with the available literature data. Results demonstrated that the simulations could be helpful for taking decisions on agricultural biogas plant operation or experimental set-ups, if used advisedly. PMID:21974886

Zhou, Haidong; Löffler, Daniel; Kranert, Martin

2011-09-08

285

Long-term performance of high-rate anaerobic reactors for the treatment of oily wastewater.  

PubMed

Complex oily wastewater from a food industry was treated in three different UASB reactors at different operating conditions. Although all three systems achieved fat, oil, and grease (FOG) and COD removal efficiencies above 80% at an organic loading of 3 kg COD/m3 x d, system performance deteriorated sharply at higher loading rates, and the presence of high FOG caused a severe sludge flotation resulting in failure. Initially, FOG accumulated onto the biomass which led to sludge flotation and washout of biomass. The loss of sludge in the bed increased the FOG loading to the biomass and failure ensued. Contrary to previous findings, accumulation of FOG rather than influent FOG concentrations or volumetric FOG loading rate was the most importantfactor governing the high-rate anaerobic reactor performance. The critical accumulated FOG loading was identified as 1.04 +/- 0.13 g FOG/g VSS for all three reactors. Furthermore, FOG accumulation onto the biomass was identified mainly as palmitic acid (>60%) whereas the feed LCFA contained only 30% of palmitic acid and 50% of oleic acid. PMID:17120582

Jeganathan, Jeganaesan; Nakhla, George; Bassi, Amarjeet

2006-10-15

286

Benchmarking of Software and Methods for Use in Transient Multidimensional Fuel Performance with Spatial Reactor Kinetics  

SciTech Connect

The key physics involved in accurate prediction of reactor-fuel-element behavior includes neutron transport and thermal hydraulics. The thermal hydraulic feedback mechanism is primarily provided through cross sections to the neutron transport that are temperature and density dependent. Historically, this coupling was primarily seen only in reactor simulators, which are well suited to model the reactor core, giving only a coarse treatment to individual fuel pins as well as simple models for thermal distribution calculations. This poor resolution on the primary coupling mechanisms can lead to conservatisms that should be removed to improve fuel design and performance. This work seeks to address the resolution of space-time-dependent neutron kinetics with thermal feedback within the fuel pin scale in the multiphysics framework. The specific application of this new capability is transient performance analysis of space-time-dependent temperature distribution of fuel elements. The coupling between the neutron transport and the thermal feedback is extremely important in this highly coupled problem, primarily applicable to reactivity-initiated-accidents (RIAs) and loss-of-coolant-accidents (LOCAs). The capability developed will include the coupling of the time-dependent neutron transport with the time-dependent thermal diffusion capability. An improvement in resolution and coupling is proposed by developing neutron transport models that are internally coupled with high fidelity within fuel pin thermal calculations in a multiphysics framework. Good agreement is shown with benchmarks and problems from the literature of RIAs and LOCAs for the tools used.

Banfield, James E [ORNL; Clarno, Kevin T [ORNL; Hamilton, Steven P [ORNL; Maldonado, G Ivan [ORNL; Philip, Bobby [ORNL; Baird, Mark L [ORNL

2012-01-01

287

Treatment of Slaughter House Wastewater in a Sequencing Batch Reactor: Performance Evaluation and Biodegradation Kinetics  

PubMed Central

Slaughterhouse wastewater contains diluted blood, protein, fat, and suspended solids, as a result the organic and nutrient concentration in this wastewater is vary high and the residues are partially solubilized, leading to a highly contaminating effect in riverbeds and other water bodies if the same is let off untreated. The performance of a laboratory-scale Sequencing Batch Reactor (SBR) has been investigated in aerobic-anoxic sequential mode for simultaneous removal of organic carbon and nitrogen from slaughterhouse wastewater. The reactor was operated under three different variations of aerobic-anoxic sequence, namely, (4+4), (5+3), and (3+5) hr. of total react period with two different sets of influent soluble COD (SCOD) and ammonia nitrogen (NH4+-N) level 1000 ± 50?mg/L, and 90 ± 10?mg/L, 1000 ± 50?mg/L and 180 ± 10?mg/L, respectively. It was observed that from 86 to 95% of SCOD removal is accomplished at the end of 8.0?hr of total react period. In case of (4+4) aerobic-anoxic operating cycle, a reasonable degree of nitrification 90.12 and 74.75% corresponding to initial NH4+-N value of 96.58 and 176.85?mg/L, respectively, were achieved. The biokinetic coefficients (k, Ks, Y, kd) were also determined for performance evaluation of SBR for scaling full-scale reactor in future operation.

Kundu, Pradyut; Debsarkar, Anupam; Mukherjee, Somnath

2013-01-01

288

Experimental Evaluation of the Thermal Performance of a Water Shield for a Surface Power Reactor  

SciTech Connect

Water based reactor shielding is being investigated for use on initial lunar surface power systems. A water shield may lower overall cost (as compared to development cost for other materials) and simplify operations in the setup and handling. The thermal hydraulic performance of the shield is of significant interest. The mechanism for transferring heat through the shield is natural convection. Natural convection in a 100 kWt lunar surface reactor shield design is evaluated with 2 kW power input to the water in the Water Shield Testbed (WST) at the NASA Marshall Space Flight Center. The experimental data from the WST is used to validate a CFD model. Performance of the water shield on the lunar surface is then predicted with a CFD model anchored to test data. The experiment had a maximum water temperature of 75 deg. C. The CFD model with 1/6-g predicts a maximum water temperature of 88 deg. C with the same heat load and external boundary conditions. This difference in maximum temperature does not greatly affect the structural design of the shield, and demonstrates that it may be possible to use water for a lunar reactor shield.

Pearson, J. Boise; Stewart, Eric T. [NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Reid, Robert S. [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States)

2007-01-30

289

Biogas Digester: A Discussion on Factors Affecting Biogas Production and Field Investigation of a Novel Duplex Digester  

Microsoft Academic Search

Utilisation of biogas has gained importance in recent years, mainly due to the availability of cheap raw materials and environmental compatibility. Further, with an increase in the cost of petroleum products, biogas can be an effective alternative source of energy for cooking, lighting, food processing, irrigation and several other requirements. In essence, a biogas digester involves anaerobic fermentation in which

P. Mahanta; U. K. Saha; A. Dewan; P. Kalita; B. Buragohain

290

Nuclear Systems Enhanced Performance Program, Maintenance Cycle Extension in Advanced Light Water Reactor Design  

SciTech Connect

A renewed interest in new nuclear power generation in the US has spurred interest in developing advanced reactors with features which will address the public's concerns regarding nuclear generation. However, it is economic performance which will dictate whether any new orders for these plants will materialize. Economic performance is, to a great extent, improved by maximizing the time that the plant is on-line generating electricity relative to the time spent off-line conducting maintenance and refueling. Indeed, the strategy for the advanced light water reactor plant IRIS (International Reactor, Innovative and Secure) is to utilize an eight year operating cycle. This report describes a formalized strategy to address, during the design phase, the maintenance-related barriers to an extended operating cycle. The top-level objective of this investigation was to develop a methodology for injecting component and system maintainability issues into the reactor plant design process to overcome these barriers. A primary goal was to demonstrate the applicability and utility of the methodology in the context of the IRIS design. The first step in meeting the top-level objective was to determine the types of operating cycle length barriers that the IRIS design team is likely to face. Evaluation of previously identified regulatory and investment protection surveillance program barriers preventing a candidate operating PWR from achieving an extended (48 month) cycle was conducted in the context of the IRIS design. From this analysis, 54 known IRIS operating cycle length barriers were identified. The resolution methodology was applied to each of these barriers to generate design solution alternatives for consideration in the IRIS design. The methodology developed has been demonstrated to narrow the design space to feasible design solutions which enable a desired operating cycle length, yet is general enough to have broad applicability. Feedback from the IRIS design team indicates that the proposed solutions to the investigated operating cycle length barriers are both feasible and consistent with sound design practice.

Professor Neill Todreas

2001-10-01

291

Biogas production potential from cotton wastes  

Microsoft Academic Search

The anaerobic treatability and methane generation potential of three different cotton wastes namely, cotton stalks, cotton seed hull and cotton oil cake were determined in batch reactors. In addition, the effects of nutrient and trace metal supplementation were also investigated. To this purpose biochemical methane potential (BMP) experiments were performed for two different waste concentrations, namely 30 and 60g\\/l. The

A. Isci; G. N. Demirer

2007-01-01

292

Fuel Cells on Bio-Gas (Presentation)  

SciTech Connect

The conclusions of this presentation are: (1) Fuel cells operating on bio-gas offer a pathway to renewable electricity generation; (2) With federal incentives of $3,500/kW or 30% of the project costs, reasonable payback periods of less than five years can be achieved; (3) Tri-generation of electricity, heat, and hydrogen offers an alternative route to solving the H{sub 2} infrastructure problem facing fuel cell vehicle deployment; and (4) DOE will be promoting bio-gas fuel cells in the future under its Market Transformation Programs.

Remick, R. J.

2009-03-04

293

Estimation of Neutronic Performance in a Hybrid Reactor with Regression Analysis  

NASA Astrophysics Data System (ADS)

This study presents regression analysis method used for prediction and investigation of neutronic performance in a hybrid reactor using UO2 fuel and Flibe (Li2BeF4) coolant. The 235U fraction is increased gradually from 0 to 4% stepped by 1% and the 6Li fraction within the Flibe coolant is enriched gradually to 30, 60 and 90% from 7.5%. Relations between 235U fuel fraction and lithium (6Li) enrichment are investigated for the estimation of neutronic performance as the tritium breeding ratio (TBR), energy multiplication factor (M), total fission rate (?f), 238U ( n, ?) reaction and fissile fuel breeding (FFB) in the hybrid reactor. Regression analysis by results obtained by using the code (XSDRNPM/SCALE5) for TBR, M, ?f, 238U ( n, ?) and FFB are performed. The results of the regression analysis and the values obtained by using the code (XSDRNPM/SCALE5) are compared with respect to the TBR, M, ?f, 238U ( n, ?) and FFB of the reactor. The values calculated from the obtained formulations with regression analysis are found to be in good agreement with results obtained by using the code (XSDRNPM/SCALE5). It is observed that the derived equations from regression analysis could provide an accurate computation of the neutronic performances so that these equations could use for the prediction of TBR, M, ?f, 238U ( n, ?) and FFB. In addition, correlation matrix is calculated to determine the degree of relationship between variables as TBR, M, ?f, 238U ( n, ?) and FFB.

Ac?r, Adem; Alakoç, Nilüfer Pekin; Y?ld?z, Kadir

2009-12-01

294

Multi criteria sustainability assessment of biogas production in Kenya  

Microsoft Academic Search

► To produce biogas from waste in Kenya, energy inputs are limited to 1.89MJ\\/mbiogas3. ► The energy invested in biogas production for 20years can be recouped in 26months of digester operation. ► Kerosene replacement by biogas resulted in GHG reduction of up to 1.09KgCO2eq\\/mbiogas3. ► Biogas production yielded a fossil energy replacement saving of up to 37$Cents\\/mbiogas3. ► Tubular biogas

Charles Nzila; Jo Dewulf; Henri Spanjers; David Tuigong; Henry Kiriamiti; Herman van Langenhove

2012-01-01

295

Biogas foer vaerme, el-, och drivmedelsproduktion. (Biogas for production of heat, power and automotive fuels).  

National Technical Information Service (NTIS)

This report gives a description of suitable techniques for production from biogas of heat, power and automotive fuels. Techniques for gas purification and load equalization are also described. Today, district heat production is the most common field of ap...

E. Stroem T. Ekeborg

1991-01-01

296

Design consideration and economic analysis of a community size biogas unit  

SciTech Connect

At present, various organizations in Pakistan are involved in RandD work in biogas technology. Most of them are government organizations. The units developed or advertised by these organizations are of small size, i.e., for a single family, to provide gas for cooking and lighting only. In this paper, the design of a community-size biogas unit for power generation has been discussed based on hydraulic flow characteristics. The type of digesters which have been discussed are plug flow, arbitrary flow and complete mix flow. As the biological activity of the organic material in the reactor depends on the residence time and also on the temperature of the digesting liquor, hence the flow characteristics play a major role in the sizing of the digestion reactor tank. A diesel engine coupled with the biogas unit has been discussed. This not only provides power for pumping water, power for cottage industries, etc., but also the waste heat from the internal combustion engine can be used to heat the digester or for other heating needs. The economic evaluation of such a plant has been completed and the payback period has been calculated.

Abbus, S.P.

1983-12-01

297

Process for electric power production using a biogas  

SciTech Connect

A process is described for the production of electric power with a biogas used as a fuel for an electric power producing combustion turbine which drives a generator. The turbine will accept such a biogas only at a temperature below a predetermined temperature, wherein a biomass is gasified to produce a hot stream of a biogas. The biogas is at temperatures of between about 650/sup 0/-875/sup 0/C and contains vaporized tar components and solid particulate matter. It is characterized in that: the hot stream of biogas, consisting essentially of a biogas, vaporized tars and solid particulate matter, has water injected thereto partially cool the biogas to a temperature below the predetermined temperature by vaporization of the water. However, the biogas is above a temperature at which the vaporized tars in the biogas would condense out of the stream; filtering the partially cooled biogas to remove the particulate matter; and directly charging the partially cooled, filtered biogas containing the vaporized water and vaporized tars to an electric power producing combustion turbine to produce electric power.

Archer, D.H.; Bauer, F.I.; Vidt, E.J.

1987-01-27

298

Performance of nonconcentrating solar photocatalytic oxidation reactors; Part 2: Shallow pond configuration  

SciTech Connect

A solar photocatalytic oxidation facility has been fabricated in which the destruction of 4-chlorophenol (4CP) is tested in three adjacent shallow pond reactors. Each of the reactors has depths of 5.1, 10.2, and 15.3 cm (2, 4, and 6 in.), respectively. It is found that 4CP is successfully oxidized with the photocatalyst, titanium dioxide (TiO[sub 2]), suspended in a slurry or adhered to a fiberglass mesh. The pond reactors, however, perform better with the slurry. It has also been found that the first-order rate constant for oxidation of 4CP increases with decreasing initial concentration. For the same incident ultraviolet (UV) intensity, catalyst loading, and initial solute concentration, the oxidation rate of 4CP is invariant provided the aperture to volume ratio is fixed. It has been determined that the 4CP solution contains sufficient dissolved oxygen to support the photocatalytic oxidation process. Direct evidence is provided to demonstrate that the utilization of photons in the photocatalytic process becomes less efficient as the number of incident photons on the catalyst increases.

Wyness, P.; Klausner, J.F.; Goswami, D.Y.; Schanze, K.S. (Univ. of Florida, Gainesville, FL (United States))

1994-02-01

299

Performance of autotrophic nitrogen removal in the granular sludge bed reactor.  

PubMed

The autotrophic nitrogen removal process in the granular sludge bed reactor (GSB-ANR process) is a new and promising biotechnology for nitrogen removal from wastewater, which requires single reactor, simple operation and inorganic carbon. The results showed that the GSB-ANR process could be successfully started up with nitrifying granular sludge as inoculum. The volumetric nitrogen loading rate and the volumetric nitrogen removal rate reached 5.44 and 2.57kgNm(-3)day(-1), respectively, which were significantly higher than the level reported for the autotrophic nitrogen removal processes in single reactor. The predominant functional microorganisms were from Planctomycetes and Nitrosomonas. The excellent performance of GSB-ANR process was ascribed to: (a) The high activities of aerobic ammonia-oxidizing bacteria (AOB) and anaerobic ammonium oxidation (ANAMMOX) bacteria; (b) the good settlability of the granular sludge; (c) the suitable DO concentration that satisfied the oxygen requirement of AOB and prevented ANAMMOX bacteria from oxygen inhibition. PMID:22940302

Wang, Lan; Zheng, Ping; Chen, Tingting; Chen, Jianwei; Xing, Yajuan; Ji, Qixing; Zhang, Meng; Zhang, Jiqiang

2012-08-07

300

Calculational methodology and associated uncertainties: Sensitivity and uncertainty analysis of reactor performance parameters  

SciTech Connect

This chapter considers the calculational methodology and associated uncertainties both for the design of large LMFBR's and the analysis of critical assemblies (fast critical experiments) as performed by several groups within the US. Discusses cross-section processing; calculational methodology for the design problem; core physics computations; design-oriented approximations; benchmark analyses; and determination of calculational corrections and associated uncertainties for a critical assembly. Presents a detailed analysis of the sources of calculational uncertainties for the critical assembly ZPR-6/7 to illustrate the quantitative assessment of calculational correction factors and uncertainties. Examines calculational uncertainties that arise from many different sources including intrinsic limitations of computational methods; design-oriented approximations related to reactor modeling; computational capability and code availability; economic limitations; and the skill of the reactor analyst. Emphasizes that the actual design uncertainties in most of the parameters, with the possible exception of burnup, are likely to be less than might be indicated by the results presented in this chapter because reactor designers routinely apply bias factors (usually derived from critical experiments) to their calculated results.

Kujawski, E.; Weisbin, C.R.

1982-01-01

301

Application of an anaerobic hybrid reactor for petrochemical effluent treatment.  

PubMed

An anaerobic hybrid reactor (UASB/Filter) was used for petrochemical wastewater treatment in mesophilic conditions. The seeded flocculent sludge from a UASB plant treating dairy wastewater, acclimatized to the petrochemical wastes in a two-stage operation. After start up, under steady-state conditions, experiments were conducted at OLRs of between 0.5 and 24 kg TCOD m(-3) d(-1), hydraulic retention times (HRT) of 4-48 h and up-flow velocities 0.021-0.25 mh(-1). Removal efficiencies in the range of 42-86% were achieved at feed TCOD concentrations of 1,000-4,000 mg L(-1). The results of reactor performance at different operational conditions and its relations are presented and discussed in this paper. Then, the obtained data are used for determination of kinetic models. The results showed that a second-order model and a modified Stover-Kincannon model were the most appropriate models for this reactor. Finally, the biogas production data were used for the determination of biogas production kinetics. PMID:22643402

Jafarzadeh, Mohammad Taghi; Mehrdadi, Naser; Hashemian, Seyed Jamaladdin

2012-01-01

302

Effects of steam pretreatment and co-production with ethanol on the energy efficiency and process economics of combined biogas, heat and electricity production from industrial hemp  

PubMed Central

Background The study presented here has used the commercial flow sheeting program Aspen Plus™ to evaluate techno-economic aspects of large-scale hemp-based processes for producing transportation fuels. The co-production of biogas, district heat and power from chopped and steam-pretreated hemp, and the co-production of ethanol, biogas, heat and power from steam-pretreated hemp were analysed. The analyses include assessments of heat demand, energy efficiency and process economics in terms of annual cash flows and minimum biogas and ethanol selling prices (MBSP and MESP). Results Producing biogas, heat and power from chopped hemp has the highest overall energy efficiency, 84% of the theoretical maximum (based on lower heating values), providing that the maximum capacity of district heat is delivered. The combined production of ethanol, biogas, heat and power has the highest energy efficiency (49%) if district heat is not produced. Neither the inclusion of steam pretreatment nor co-production with ethanol has a large impact on the MBSP. Ethanol is more expensive to produce than biogas is, but this is compensated for by its higher market price. None of the scenarios examined are economically viable, since the MBSP (EUR 103–128 per MWh) is higher than the market price of biogas (EUR 67 per MWh). The largest contribution to the cost is the cost of feedstock. Decreasing the retention time in the biogas process for low solids streams by partly replacing continuous stirred tank reactors by high-rate bioreactors decreases the MBSP. Also, recycling part of the liquid from the effluent from anaerobic digestion decreases the MBSP. The production and prices of methane and ethanol influence the process economics more than the production and prices of electricity and district heat. Conclusions To reduce the production cost of ethanol and biogas from biomass, the use of feedstocks that are cheaper than hemp, give higher output of ethanol and biogas, or combined production with higher value products are primarily suggested. Further, practical investigations on increased substrate concentration in biogas and ethanol production, recycling of the liquid in anaerobic digestion and separation of low solids flows into solid and a liquid fraction for improved reactor applications deserves further attention.

2013-01-01

303

Aqueous processing of U-10Mo scrap for high performance research reactor fuel  

NASA Astrophysics Data System (ADS)

The Global Threat Reduction Initiative (GTRI) Conversion program, which is part of the US government's National Nuclear Security Administration (NNSA), supports the conversion of civilian use of highly enriched uranium (HEU) to low enriched uranium (LEU) for reactor fuel and targets. The reason for conversion is to eliminate the use of any material that may pose a threat to the United States or other foreign countries. High performance research reactors (HPRRs) cannot make the conversion to a standard LEU fuel because they require a more dense fuel to meet their performance requirements. As a result, a more dense fuel consisting of a monolithic uranium-molybdenum alloy containing 10% (w/w) Mo with Al cladding and a Zr bonding-layer is being considered. Significant losses are expected in the fabrication of this fuel, so a means to recycle the scrap pieces is needed. Argonne National Laboratory has developed an aqueous-processing flowsheet for scrap recovery in the fuel fabrication process for high-density LEU-monolithic fuel based on data found in the literature. Experiments have been performed to investigate dissolution conditions for solutions containing approximately 20 g-U/L and 50 g-U/L with and without Fe(NO3)3. HNO3 and HF concentrations have been optimized for timely dissolution of the fuel scrap and prevention of the formation of the U-Zr2 intermetallic, explosive complex, while meeting the requirements needed for further processing.

Youker, Amanda J.; Stepinski, Dominique C.; Maggos, Laura E.; Bakel, Allen J.; Vandegrift, George F.

2012-08-01

304

Studies of the impact of fuel enrichment on the performance of the advanced neutron source reactor  

SciTech Connect

As part of a larger study involving several organizations, the Advanced Neutron Source (ANS) Project made performance calculations for 19 different combinations of reactor core volume, fuel density and enrichment, power level, and other relevant parameters. These calculations were performed by Idaho National Engineering Laboratory (INEL) and Oak Ridge National Laboratory (ORNL). Subsequently, ORNL analyzed 14 other cases. With the aid of data from these 33 cases, the laboratory has been able to correlate the most important performance characteristics (peak thermal flux in the reflector and core life) with fuel enrichment, fuel density, and power. The correlations permits the investigation of additional cases without going to the expense of doing completely new neutronics calculations for each new one and can be used to prepare curves showing the effects of different enrichments and of different fuel densities within the entire range from existing technology to the very advanced, as yet undeveloped fuels that have been proposed from time to time.

West, C.D.

1995-01-01

305

Coal liquefaction: investigation of reactor performance, role of catalysts and PCT properties. Quarterly progress report, April 1-June 30, 1985  

SciTech Connect

The objective of this work is to investigate areas of science and technology that have been defined as being of prime interest to coal processing technology development. These areas include properties of coal liquids and slurries, reactor design, and performance in relation to reaction mechanisms. The work comprises investigations of the following high priority areas: reaction kinetics and reactor performance in direct coal liquefaction; role of catalysts in indirect liquefaction and direct coal liquefaction; and physical, chemical, and thermodynamic properties of coal liquefaction products. This report summarizes work done during the period April 1, 1985 through June 30, 1985. A detailed description of work in each of the following three tasks is presented: (1) reactor kinetics and reactor performance in direct coal liquefaction (Fischer-Tropsch process, methanol-to-gasoline process, methanol synthesis); (2) role of catalysts in direct liquefaction and in indirect coal liquefaction; and (3) physical, chemical, and thermodynamic properties of coal liquefaction products.

Brainard, A.J.; Shah, Y.T.; Tierney, J.W.; Wender, I.; Joseph, S.; Kerkar, A.; Ozturk, S.; Sayari, A.

1985-01-01

306

Modeling biogas production at landfill site  

Microsoft Academic Search

Biogas production is characteristic of municipal solid waste landfills. A knowledge of the trend of this production allows an exploitation of this energy source. The here presented model is more accurate than those that already exist as it takes the temperature variation in time and depth and the landfill settlement into account. The obtained model fits experimental data well.

L. Manna; M. C. Zanetti; G. Genon

1999-01-01

307

Large-scale biogas in China  

SciTech Connect

Recent progress in China in the development and operation of large-scale biogas plants is described. These plants have been located in climatic regions where small digesters are impractical and they include heating and mixing devices. Systems located in or near Beijing; Hangzhou, Zhejiang; Sichuan; and Foshan, Guangdong are discussed. 3 references.

Not Available

1982-01-01

308

The optimal size for biogas plants  

Microsoft Academic Search

The costs of biogas and electricity production from maize silage in relation to plant size are investigated in this paper. A survey of manufacturers’ engineering data was conducted to derive a reliable relationship between the capacity of a combined heat and power (CHP) unit and its electrical efficiency. Then a model was developed to derive cost curves for the unit

C. Walla; W. Schneeberger

2008-01-01

309

Biogas plants in Denmark: successes and setbacks  

Microsoft Academic Search

With 20 centralised plants and over 35 farmscale plants, the digestion of manure and organic waste is a well established technological practice in Denmark. These plants did not emerge without a struggle. Moreover, no new centralised plants have been established since 1998 and the development of farmscale plants has slowed down. This article reviews the experimental introduction of biogas plants

R. P. J. M. Raven; K. H. Gregersen

2007-01-01

310

Biogas/biofertilizer business handbook (third edition)  

SciTech Connect

The handbook covers biogas systems, including raw material preparation, digesters, separate gas storage tanks, use of gas to run engines, and the use of sludge as fertilizer. Also covers secondary projects such as flat-plate solar collector water heaters, composting, and bio-insecticides.

Arnott, M.

1985-07-01

311

CROPS - A BIG POTENTIAL FOR BIOGAS PRODUCTION  

Microsoft Academic Search

Anaerobic digestion of especially cultivated crops - so called biogas crops - is definitely both a contribution of fulfilling the demand for renewable energy and an alternative for farmers to secure their income. Lab-scale experiments were conducted to determine the suitability and yield capacity of various plant material (cereals, maize) as co-ferments by wet fermentation under mesophilic conditions. Results demonstrated

Monika Heiermann; Matthias Plöchl

312

Material and geometry options and performance characteristics for a test reactor  

Microsoft Academic Search

For the past 3 yr, an Idaho National Engineering Laboratory (INEL) design team has studied design options for a new test reactor to provide continued testing services after several aging test reactors in the United States are decommissioned. This new reactor, the Broad Application Test Reactor (BATR), would also fill other currently unmet needs, such as medical isotope production and

S. N. Jahshan; C. D. Fletcher; W. K. Terry

1993-01-01

313

Heat removal performance of auxiliary cooling system for the high temperature engineering test reactor during scrams  

Microsoft Academic Search

The auxiliary cooling system of the high temperature engineering test reactor (HTTR) is employed for heat removal as an engineered safety feature when the reactor scrams in an accident when forced circulation can cool the core. The HTTR is the first high temperature gas-cooled reactor in Japan with reactor outlet gas temperature of 950 °C and thermal power of 30 MW.

Takeshi Takeda; Yukio Tachibana; Tatsuo Iyoku; Satsuki Takenaka

2003-01-01

314

454 pyrosequencing analyses of bacterial and archaeal richness in 21 full-scale biogas digesters.  

PubMed

The microbial community of 21 full-scale biogas reactors was examined using 454 pyrosequencing of 16S rRNA gene sequences. These reactors included seven (six mesophilic and one thermophilic) digesting sewage sludge (SS) and 14 (ten mesophilic and four thermophilic) codigesting (CD) various combinations of wastes from slaughterhouses, restaurants, households, etc. The pyrosequencing generated more than 160,000 sequences representing 11 phyla, 23 classes, and 95 genera of Bacteria and Archaea. The bacterial community was always both more abundant and more diverse than the archaeal community. At the phylum level, the foremost populations in the SS reactors included Actinobacteria, Proteobacteria, Chloroflexi, Spirochetes, and Euryarchaeota, while Firmicutes was the most prevalent in the CD reactors. The main bacterial class in all reactors was Clostridia. Acetoclastic methanogens were detected in the SS, but not in the CD reactors. Their absence suggests that methane formation from acetate takes place mainly via syntrophic acetate oxidation in the CD reactors. A principal component analysis of the communities at genus level revealed three clusters: SS reactors, mesophilic CD reactors (including one thermophilic CD and one SS), and thermophilic CD reactors. Thus, the microbial composition was mainly governed by the substrate differences and the process temperature. PMID:23678985

Sundberg, Carina; Al-Soud, Waleed A; Larsson, Madeleine; Alm, Erik; Yekta, Sepehr S; Svensson, Bo H; Sørensen, Søren J; Karlsson, Anna

2013-06-12

315

Microfluidic enzymatic-reactors for peptide mapping: strategy, characterization, and performance.  

PubMed

The design and characterization of two kinds of poly(dimethylsiloxane)(PDMS) microfluidic enzymatic-reactors along with their analytical utility coupled to MALDI TOF and ESI MS were reported. Microfluidic devices integrated with microchannel and stainless steel tubing (SST) was fabricated using a PDMS casting technique, and was used for the preparation of the enzymatic-reactor. The chemical modification was performed by introducing carboxyl groups to PDMS surface based on ultraviolet graft polymerization of acrylic acid. The covalent and physical immobilization of trypsin was carried out with the use of the activation reagents 1-ethyl-3-(3-dimethyl aminopropyl)carbodiimide(EDC)/N-hydroxysuccinimide (NHS) and a coupling reagent poly(diallyldimethylammonium chloride)(PDDA), respectively. The properties and success of processes of trypsin immobilization were investigated by measuring contact angle, infrared absorption by attenuated total reflection spectra, AFM imaging and electropherograms. An innovative feature of the microfluidic enzymatic-reactors is the feasibility of performing on-line protein analysis by embedded SST electrode and replaceable tip. The lab-made devices provide an excellent extent of digestion of several model proteins even at the fast flow rate of 3.5 microL min(-1) for the EDC/NHS-made device and 0.8 microL min(-1) for the PDDA-made device, which afford very short residence times of 5 s and 20 s, respectively. In addition, the lab-made devices are less susceptive to memory effect and can be used for at least 50 runs in one week without noticeable loss of activity. Moreover, the degraded PDDA-made device can be regenerated by simple treatment of a HCl solution. These features are the most required for microfluidic devices used for protein analysis. PMID:15570370

Wu, Huiling; Zhai, Jianjun; Tian, Yuping; Lu, Haojie; Wang, Xiaoyan; Jia, Weitao; Liu, Baohong; Yang, Pengyuang; Xu, Yunmin; Wang, Honghai

2004-11-10

316

Investigation on the Neutronic Performance of a Fusion Reactor Using Flibe with Heavy Metal Fluorides  

Microsoft Academic Search

   Using liquid wall between the plasma and solid first wall in a fusion reactor allows to use high neutron wall loads and could eliminate frequent replacement of the first wall structure during reactor’s lifetime. Liquid wall should have a certain effective or optimum thickness to extend solid first wall lifetime to reactor’s lifetime and supply sufficient tritium for deuterium–tritium (DT)

Mustafa Übeyli

2006-01-01

317

Investigations of reactor performance, role of inherent catalysts, hydrogen donor solvents, and PCT properties of coal liquids and slurries  

SciTech Connect

The published and the unpublished non-proprietary data and calculations available on various scale coal liquefaction units were used to carry out a review of several aspects of reaction kinetics and reactor performance. The performance of a coal liquefaction reactor depends not only on the intrinsic kinetics but also on prevailing hydrodynamic, mixing and mass transfer characteristics. The scale-up of the reactor also depends on how faithfully one can predict or reproduce its characteristics in larger sized reactors. The literature for simple air-water, two- and three-phase bubble column reactors is analyzed and the suitability of existing correlations for coal liquefaction reactors is discussed. Kinetic models for coal liquefaction are evaluated. The models are divided into three categories: rate models, lumped models, and correlation models. All these models, however, have a basic drawback, that the applicability is restricted to the experimental data on which the model is based. Hydrogen consumption kinetics and the thermal behavior of coal liquefaction reactors are considered. Hydrogen consumption is one of the major operating costs in direct coal liquefaction. Hydrogen consumption depends on reaction temperature, hydrogen partial pressure, nature and concentration of catalyst (recycle ash content in the case of the SRC-II process) and slurry residence time. It is important to know the thermal behavior of a large scale reactor as a function of reaction operating conditions including reactor inlet temperature, pressure, slurry residence time, nature of coal, solvent, and concentration of coal and catalyst in the slurry phase. The thermal behavior of the SRC-II reactor is discussed with the possibility of existence of multiple steady states, and the ways to control them.

Albal, R.; Brainard, A.; Godbole, S.; Kelkar, B.; Kulkarni, A.; Shah, Y.; Tierney, J.; Wender, I.

1983-10-01

318

Performance Analyses of 38 kWe Turbo-Machine Unit for Space Reactor Power Systems  

NASA Astrophysics Data System (ADS)

This paper developed a design and investigated the performance of 38 kWe turbo-machine unit for space nuclear reactor power systems with Closed Brayton Cycle (CBC) energy conversion. The compressor and turbine of this unit are scaled versions of the NASA's BRU developed in the sixties and seventies. The performance results of turbo-machine unit are calculated for rotational speed up to 45 krpm, variable reactor thermal power and system pressure, and fixed turbine and compressor inlet temperatures of 1144 K and 400 K. The analyses used a detailed turbo-machine model developed at the University of New Mexico that accounts for the various energy losses in the compressor and turbine and the effect of compressibility of the He-Xe (40 mole/g) working fluid with increased flow rate. The model also accounts for the changes in the physical and transport properties of the working fluid with temperature and pressure. Results show that a unit efficiency of 24.5% is achievable at rotation speed of 45 krpm and system pressure of 0.75 MPa, assuming shaft and electrical generator efficiencies of 86.7% and 90%. The corresponding net electric power output of the unit is 38.5 kWe, the flow rate of the working fluid is 1.667 kg/s, the pressure ratio and polytropic efficiency for the compressor are 1.60 and 83.1%, and 1.51 and 88.3% for the turbine.

Gallo, Bruno M.; El-Genk, Mohamed S.

2008-01-01

319

Computational Neutronics Methods and Transmutation Performance Analyses for Light Water Reactors  

SciTech Connect

The urgency for addressing repository impacts has grown in the past few years as a result of Spent Nuclear Fuel (SNF) accumulation from commercial nuclear power plants. One obvious path that has been explored by many is to eliminate the transuranic (TRU) inventory from the SNF thus reducing the need for additional long term repository storage sites. One strategy for achieving this is to burn the separated TRU elements in the currently operating U.S. Light Water Reactor (LWR) fleet. Many studies have explored the viability of this strategy by loading a percentage of LWR cores with TRU in the form of either Mixed Oxide (MOX) fuels or Inert Matrix Fuels (IMF). A task was undertaken at INL to establish specific technical capabilities to perform neutronics analyses in order to further assess several key issues related to the viability of thermal recycling. The initial computational study reported here is focused on direct thermal recycling of IMF fuels in a heterogeneous Pressurized Water Reactor (PWR) bundle design containing Plutonium, Neptunium, Americium, and Curium (IMF-PuNpAmCm) in a multi-pass strategy using legacy 5 year cooled LWR SNF. In addition to this initial high-priority analysis, three other alternate analyses with different TRU vectors in IMF pins were performed. These analyses provide comparison of direct thermal recycling of PuNpAmCm, PuNpAm, PuNp, and Pu.

M. Asgari; B. Forget; S. Piet; R. Ferrer; S. Bays

2007-03-01

320

Effect of increasing nitrobenzene loading rates on the performance of anaerobic migrating blanket reactor and sequential anaerobic migrating blanket reactor\\/completely stirred tank reactor system  

Microsoft Academic Search

A laboratory scale anaerobic migrating blanket reactor (AMBR) reactor was operated at nitrobenzene (NB) loading rates increasing from 3.33 to 66.67gNB\\/m3day and at a constant hydraulic retention time (HRT) of 6 days to observe the effects of increasing NB concentrations on chemical oxygen demand (COD), NB removal efficiencies, bicarbonate alkalinity, volatile fatty acid (VFA) accumulation and methane gas percentage. Moreover,

Özlem Selçuk Ku?çu; Delia Teresa Sponza

2009-01-01

321

Membrane coupled high-performance compact reactor: a new MBR system for advanced wastewater treatment.  

PubMed

This study examined the potential and limitations of a new submerged membrane system coupled with a High-performance Compact Reactor (HCR) to take advantages of both systems. The configuration and installation position in the HCR of the membrane module were thoroughly investigated for the optimum design of a submerged membrane coupled with HCR, e.g., MHCR. Inside the draft tube proved to be better location rather than outside the draft tube or in the degas tank and an open-type configuration of a membrane module has an advantage over a fixed-type configuration in terms of membrane fouling. Comparison of the innovative MHCR with a conventional membrane bioreactor (MBR) was made to identify and prove the superiority of MHCR to MBR with respect to the membrane performance. The MHCR has shown the great potential, particularly for the treatment of wastewater of high organic strength. PMID:15913704

Yeon, Kyung-Min; Park, Jong-Sang; Lee, Chung-Hak; Kim, Soo-Myung

2005-05-01

322

Performance of an Anaerobic Baffled Reactor (ABR) in treatment of cassava wastewater  

PubMed Central

The performance of an anaerobic baffled reactor (ABR) was evaluated in the treatment of cassava wastewater, a pollutant residue. An ABR divided in four equal volume compartments (total volume 4L) and operated at 35ºC was used in cassava wastewater treatment. Feed tank chemical oxygen demand (COD) was varied from 2000 to 7000 mg L-1 and it was evaluated the most appropriated hydraulic retention time (HRT) for the best performance on COD removal. The ABR was evaluated by analysis of COD (colorimetric method), pH, turbidity, total and volatile solids, alkalinity and acidity. Principal component analysis (PCA) was carried to better understand data obtained. The system showed buffering ability as acidity decreased along compartments while alkalinity and pH values were increased. There was particulate material retention and COD removal varied from 83 to 92% for HRT of 3.5 days.

Ferraz, Fernanda M.; Bruni, Aline T.; Del Bianchi, Vanildo L.

2009-01-01

323

Fusion performance analysis of plasmas with reversed magnetic shear in the Tokamak Fusion Test Reactor  

SciTech Connect

A case for substantial loss of fast ions degrading the performance of tokamak fusion test reactor plasmas [Phys. Plasmas {bold 2}, 2176 (1995)] with reversed magnetic shear (RS) is presented. The principal evidence is obtained from an experiment with short (40{endash}70 ms) tritium beam pulses injected into deuterium beam heated RS plasmas [Phys. Rev. Lett. {bold 82}, 924 (1999)]. Modeling of this experiment indicates that up to 40{percent} beam power is lost on a time scale much shorter than the beam{endash}ion slowing down time. Critical parameters which connect modeling and experiment are: The total 14 MeV neutron emission, its radial profile, and the transverse stored energy. The fusion performance of some plasmas with internal transport barriers is further deteriorated by impurity accumulation in the plasma core. {copyright} {ital 1999 American Institute of Physics.} thinsp

Ruskov, E.; Bell, M.; Budny, R.V.; McCune, D.C.; Medley, S.S.; Nazikian, R.; Synakowski, E.J.; von Goeler, S.; White, R.B.; Zweben, S.J. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

1999-08-01

324

Performance of Magnet Insulation Systems at Low Temperature and After Reactor Irradiation  

NASA Astrophysics Data System (ADS)

Advanced composite materials reinforced with boron-free glass fibers are candidate insulation materials for fusion magnets, in particular for ITER. Thus, these systems require an excellent performance and mechanical integrity after irradiation. The present innovative organic insulation system consists of R-glass fiber reinforced tapes impregnated with an advanced cyanate-ester/epoxy resin. This composite is suitable for vacuum-pressure impregnation. In order to assess the radiation resistance of the mechanical properties, the laminate was irradiated in the TRIGA reactor (Vienna) to the ITER design fluence level of 1×1022 m-2 (E>0.1 MeV). The blend was screened at 77 K using the static tensile and short-beam-shear test prior to and after irradiation. In addition, tension-tension fatigue measurements were done in order to investigate the material performance under pulsed operating conditions.

Bittner-Rohrhofer, K.; Humer, K.; Fillunger, H.; Maix, R. K.; Weber, H. W.

2004-06-01

325

On the Neutronic Performance of Hylife-II Reactor Fuelled with Carbide Fuels  

NASA Astrophysics Data System (ADS)

In this study, neutronic analysis of the HYLIFE-II reactor was investigated by inserting fuel rods containing UC or mixed ThC-UC into reflector zone partially. Four different coolants, namely, flibe, helium, natural lithium, and light water were considered in the fissile fuel breeding zone for comparison. Neutron transport calculations per incident (D,T) fusion neutron were performed by using the code Scale 4.3 under resonance-effect and resonance-free conditions. Numerical results pointed out that replacing the reflector zone by fissile fuel breeding zone even with a thickness of 14 cm improved the neutronic performance remarkably with respect to energy amplification and fissile fuel breeding.

Yap?c?, Hüseyin; Übeyli, Mustafa

2006-06-01

326

Performance evaluation of cigarette filter rods as a biofilm carrier in an anaerobic moving bed biofilm reactor.  

PubMed

Biocarriers are an important component of anaerobic moving bed biofilm reactors (AMBBRs). In this study, the capability of cigarette filter rods (CFRs) as a biocarrier in an anaerobic moving bed biofilm reactor was evaluated. Two similar lab-scale anaerobic moving bed biofilm reactors were undertaken using Kaldnes-K3 plastic media and cigarette filter rods (wasted filters from tobacco factories) as biofilm attachment media for wastewater treatment. Organic substance and total posphours (TP) removal was investigated over 100 days. Synthetic wastewater was prepared with ordinary water and glucose as the main sources of carbon and energy, plus balanced macro- and micro-nutrients. Process performance was studied by increasing the organic loading rate (OLR) in the range of 1.6-4.5 kg COD/m3 x d. The COD average removal efficiency were 61.3% and 64.5% for AMBBR with cigarette filter rods (Reactor A) and AMBBR with Kaldnes plastic media (Reactor B), respectively. The results demonstrate that the performance of the AMBBR containing 0.25 litres of cigarette filters was comparable with a similar reactor containing 1.5 litres of Kaldnes plastic media. An average phosphorus removal of 67.7% and 72.9% was achieved by Reactors A and B, respectively. PMID:22988642

Sabzali, Ahmad; Nikaeen, Mahnaz; Bina, Bijan

327

Performance evaluation and kinetic modeling of the start-up of a UASB reactor treating municipal wastewater at low temperature  

Microsoft Academic Search

A kinetic modeling-based study was carried out to evaluate the start-up performance of a 10-L up-flow anaerobic sludge blanket\\u000a (UASB) reactor treating municipal wastewater under different organic and hydraulic loading conditions. The reactor was operated\\u000a for 105 days (around 4 months) below 20 °C and with three different hydraulic retention times of 24, 12 and 5 h. Imposed volumetric\\u000a organic loading rates (OLR) ranged

F. Ilter Turkdogan-Aydinol; Kaan Yetilmezsoy; Sezen Comez; Hurrem Bayhan

2011-01-01

328

Performance of an up-flow anaerobic stage reactor (UASR) in the treatment of pharmaceutical wastewater containing macrolide antibiotics  

Microsoft Academic Search

The performance of an up-flow anaerobic stage reactor (UASR) treating pharmaceutical wastewater containing macrolide antibiotics was investigated. Specifically, it was determined whether a UASR could be used as pre-treatment system at an existing pharmaceutical production plant to reduce the antibiotics in the trade effluent. Accordingly, a UASR was developed with an active reactor volume of 11L being divided into four

Shreeshivadasan Chelliapan; Thomas Wilby; Paul J. Sallis

2006-01-01

329

Core performance and proliferation resistance prospective of a novel natural uranium fueled, heavy water moderated nuclear research reactor  

Microsoft Academic Search

Three-dimensional burnup calculations were carried out to analyze the performance and proliferation resistance prospective of a novel natural uranium fueled, D2O moderated, D2O cooled and graphite reflected nuclear research reactor. The lattice simulation code WIMS-D\\/4 generated microscopic group constants, (?a, ?f, ?tr, ? etc.,), in conjunction with the diffusion theory based reactor core simulation code CITATION was employed in this

Mohammad Javed Khan; Aslam; Nasir Ahmad

2006-01-01

330

Influence of liquid-phase mass transfer on the performance of a stirred anaerobic sequencing batch reactor containing immobilized biomass  

Microsoft Academic Search

This paper reports on the influence of the liquid-phase mass transfer on the performance of a stirred anaerobic sequencing batch reactor treating low-strength wastewater. The biomass was immobilized in cubical polyurethane foam particles (5mm per side). The 4.2l volume reactor was operated at a temperature of 30°C. A synthetic substrate with a mean chemical oxygen demand (COD) of 560±53mg\\/l was

S. A. Cubas; E. Foresti; J. A. D. Rodrigues; S. M. Ratusznei; M. Zaiat

2004-01-01

331

Development of empirical models for performance evaluation of UASB reactors treating poultry manure wastewater under different operational conditions  

Microsoft Academic Search

A nonlinear modeling study was carried out to evaluate the performance of UASB reactors treating poultry manure wastewater under different organic and hydraulic loading conditions. Two identical pilot scale up-flow anaerobic sludge blanket (UASB) reactors (15.7L) were run at mesophilic conditions (30–35°C) in a temperature-controlled environment with three hydraulic retention times (?) of 15.7, 12 and 8.0 days. Imposed volumetric

Kaan Yetilmezsoy; Suleyman Sakar

2008-01-01

332

Effect of Reaction and Permeation Rates on the Performance of a Catalytic Membrane Reactor for Methylcyclohexane Dehydrogenation  

Microsoft Academic Search

The effect of the relative rates of reaction and H2 permeation through palladium-silver (Pd-Ag) membranes upon the performance of a catalytic membrane reactor (CMR) for methylcyclohexane dehydrogenation has been investigated. Mathematical models have been used to identify the conditions at which a membrane reactor gives yields of toluene (TOL) and H2 significantly in excess of equilibrium values at throughputs of

Jawad K. Ali; D. W. T. Rippin

1994-01-01

333

Evaluation of performance and microbial community in a two-stage UASB reactor pretreating acrylic fiber manufacturing wastewater  

Microsoft Academic Search

A two-stage UASB reactor was employed to pretreat acrylic fiber manufacturing wastewater. Mesophilic operation (35±0.5°C) was performed with hydraulic retention time (HRT) varied between 28 and 40h. Mixed liquor suspended solids (MLSS) in the reactor was maintained about 8000mg\\/L. The results showed COD and sulfate removal could be kept at 51% and 75%, respectively, when the HRT was no less

Jin Li; Jun Wang; Zhaokun Luan; Yanqin Deng; Lin Chen

2011-01-01

334

Performance of an aerobic granular sequencing batch reactor fed with wastewaters contaminated with Zn2+.  

PubMed

The main aim of this study was to investigate the performance of an aerobic granular sludge sequencing batch reactor (AGS-SBR) receiving water streams supplied with different loads of Zn(2+) (50 and 100 mg L(-1)) during an operation of 866 cycles (ca. 109 days). When the metal was not fed, chemical oxygen demand (COD), PO4(3-) and NH4(+) were efficiently removed, with efficiencies of 56, 23 and 72% respectively. DGGE profiles showed that Zn(2+) supply negatively affected the bacterial diversity and community structure of the granules. Consequently, the shock loadings with Zn(2+), particularly at the higher levels (100 mg L(-1)), affected the nutrient removal in the AGS-SBR, although the reactor still generally complied with admissible legal values concerning organic matter, nitrogen and Zn. Simultaneous removal of PO4(3-) and TSS in such conditions needs further refining but the application of aerobic granular SBR in the treatment of Zn(2+) contaminated wastewaters seems viable. PMID:23880431

Marques, Ana P G C; Duque, Anouk F; Bessa, Vânia S; Mesquita, Raquel B R; Rangel, António O S S; Castro, Paula M L

2013-07-20

335

Full-scale sequencing batch reactor (SBR) for domestic wastewater: performance and diversity of microbial communities.  

PubMed

This work describes the performance and microbial diversity in a sequencing batch reactor of a decentralized full-scale system for urban wastewater treatment under limited aeration. The removal efficiency was: 83% for soluble chemical oxygen demand (SCOD), 60% for N-NH4(+), 70% for total suspended solids (TSS) and 80% for volatile suspended solids (VSS). The biomass concentration had a maximum value around 8.7gVSSL(-1) for organic load rate of 0.6gCODL(-1)d(-1). The food/microorganism ratios showed average of 0.2gCOD/gVSSd. The sludge bacterial flocs were formed an irregular arrangement with organisms attached such as Euglypha sp. and pedunculate ciliates. It was observed the presence of Bacteria domains including Nitrosomonas spp., Nitrobacter spp., Nitrospira and C. "Accumulibacter" cluster. The DPAO activity was 70%. Denaturing gradient gel electrophoresis showed changes in ribotype number over biological treatment time among the groups observed being some are linked to nutrient removal. The reactor showed viability to treat domestic wastewater. PMID:23411457

Fernandes, Heloísa; Jungles, Mariele K; Hoffmann, Heike; Antonio, Regina V; Costa, Rejane H R

2013-01-22

336

Microbial community structure and performance of an anaerobic reactor digesting cassava pulp and pig manure.  

PubMed

Microbial community dynamics in response to changes in substrate types (i.e. pig manure (PM), cassava pulp (CP) and mixtures of PM and CP) were investigated in an anaerobic continuously stirred tank reactor (CSTR). Molecular identification of bacterial and archaeal domains were performed, using a 16S rDNA clone library with polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) screening and phylogenetic analysis. Analysis of bacterial clone libraries revealed that the differences in the community structure corresponded to the substrate types. However, the Bacteroidetes were the most abundant group in all substrates, followed by the Clostridia. With pure PM, the dominant bacterial groups were Bacteroidales, Clostridia and Paludibacter. With a co-substrate, at CP to PM (CP:PM) ratio of 50:50, the sequences analysis revealed the greatest diversity of bacterial communities at class level, and the sequences affiliated with Cytophaga sp. became an exclusive predominant. With CP alone, Bacteroides sp. was the dominant species and this reactor had the lowest diversity of bacteria. Archaea observed in the CSTR fed with all substrate types were Methanosaeta sp., Methanosaeta concilii and Methanospirillum hungatei. Among the Archaea, Methanosaeta sp. was the exclusive predominant. The relative distribution of Archaea also changed regarding to the substrate types. PMID:22864448

Panichnumsin, P; Ahring, B; Nopharatana, A; Chaiprasert, P

2012-01-01

337

Advanced Concepts for Pressure-Channel Reactors: Modularity, Performance and Safety  

NASA Astrophysics Data System (ADS)

Based on an analysis of the development of advanced concepts for pressure-tube reactor technology, we adapt and adopt the pressure-tube reactor advantage of modularity, so that the subdivided core has the potential for optimization of the core, safety, fuel cycle and thermal performance independently, while retaining passive safety features. In addition, by adopting supercritical water-cooling, the logical developments from existing supercritical turbine technology and “steam” systems can be utilized. Supercritical and ultra-supercritical boilers and turbines have been operating for some time in coal-fired power plants. Using coolant outlet temperatures of about 625°C achieves operating plant thermal efficiencies in the order of 45-48%, using a direct turbine cycle. In addition, by using reheat channels, the plant has the potential to produce low-cost process heat, in amounts that are customer and market dependent. The use of reheat systems further increases the overall thermal efficiency to 55% and beyond. With the flexibility of a range of plant sizes suitable for both small (400 MWe) and large (1400 MWe) electric grids, and the ability for co-generation of electric power, process heat, and hydrogen, the concept is competitive. The choice of core power, reheat channel number and exit temperature are all set by customer and materials requirements. The pressure channel is a key technology that is needed to make use of supercritical water (SCW) in CANDU®1 reactors feasible. By optimizing the fuel bundle and fuel channel, convection and conduction assure heat removal using passive-moderator cooling. Potential for severe core damage can be almost eliminated, even without the necessity of activating the emergency-cooling systems. The small size of containment structure lends itself to a small footprint, impacts economics and building techniques. Design features related to Canadian concepts are discussed in this paper. The main conclusion is that development of SCW pressure-channel nuclear reactors is feasible and significant benefits can be expected over other thermal-energy systems.

Duffey, Romney B.; Pioro, Igor L.; Kuran, Sermet

338

Cooling performance of a water-cooling panel system for modular high-temperature gas-cooled reactors  

Microsoft Academic Search

Experiments on a water cooling panel system were performed to investigate its heat removal performance and the temperature distribution of components for a modular high-temperature gas-cooled reactor (MHTGR). The analytical code THANPACST2 was applied to analyze the experimental results to verify the validity of the analytical method and the model.

Shoji Takada; Kunihiko Suzuki; Yoshiyuki Inagaki; Yukio Sudo

1995-01-01

339

Innovative Fusion Reactor Design Analysis: Annual Performance Report, May 15, 1988-January 31, 1989.  

National Technical Information Service (NTIS)

This report discusses the following topics on fusion reactor component design: FLiBe intermediate heat exchanger design analysis; FLiBe properties; design methodology; FLiBe system steam generator freezeup; FLiBe reactor systems studies; tritium breeding ...

A. C. Klein

1989-01-01

340

Occurrence and Abatement of Volatile Sulfur Compounds during Biogas Production  

Microsoft Academic Search

Volatile sulfur compounds (VSCs) in biogas originating from a biogas production plant and from a municipal sewage water treatment plant were identified. Samples were taken at various stages of the biogas-producing process, including upgrading the gas to vehicle-fuel quality. Solid-phase microextraction was used for preconcentra-tion of the VSCs, which were subsequently analyzed using gas chromatography in combination with mass spectrom-etry.

Fräs Annika T. Andersson; Anna Karlsson; Bo H. Svensson; Jörgen Ejlertsson

2004-01-01

341

Biogas technology – a contemporary method for processing organic wastes  

Microsoft Academic Search

Work is devoted to resolving ecological problems of the utilization of organic wastes from the Russian Federation agro-industrial\\u000a complex. A promising processing method is biochemical transformation by anaerobic fermentation in biogas units with simultaneous\\u000a production of highly effective biofertilizer and a power generation product, i.e., biogas. Biogas technology is proposed on\\u000a the basis of a bubbling bioreactor of original construction

D. Yu. Suslov; L. A. Kushchev

2010-01-01

342

Biogas curriculum: workshop, April 6-11, 1981  

SciTech Connect

This report is a curriculum guide for those interested in biogas technology. Its purpose is to develop an understanding of the science, engineering, economics, and environmental implications of the biogas technology. The purpose of the training is to encourage application of biogas process design in the US on a small scale to utilize local supplies of indigenous alternate energy sources for production of fuel, feed and fertilizer with simultaneous pollution control.

Highnote, R.

1981-12-21

343

Biogas digesters in the Peoples Republic of China  

SciTech Connect

This paper is a report on the use of biogas in China. The authors traveled in China from May 8 to June 12, 1982 during which time they visited several institutes doing research on biogas and many communes where biogas was produced and used. About 7,000,000 digesters are in actual use in China almost all of which are the small household type used for cooking and lighting.

Liljedahl, J.B.; Butler, J.; Caldwell, J.S.; Tyner, W.E.

1983-06-01

344

Degradation of household biowaste in reactors.  

PubMed

Household derived biowaste was degraded by biological methods. The system involves the combined method of low-solids (up to 10% w/v of total solids (TS)) anaerobic digestion and aerobic degradation for the recovery of energy (biogas) and the production of fine humus-like material which can be used as a soil amender or a substrate for further thermal treatment (pyrolysis, gasification). The performance of batch and continuous processes carried out in bioreactors (stirred tank reactor, air-lift) of working volume 6 and 18 dm(3), at different temperatures (25-42 degrees C) was monitored by reduction of TS, volatile solids, chemical oxygen demand, total organic carbon, C/N in time. The application of continuous process with recirculation (33%) caused that for residence time of 8-16 h the obtained degree of organic load reduction was similar to that obtained after 72-96 h of the batch process. The experimental data of batch aerobic degradation was also subjected to kinetic analysis. The sequence of the two processes: aerobic and anaerobic or anaerobic and aerobic showed that the degree of organic load reduction was similar in both cases, while the amount of produced biogas was four times higher when the first stage was anaerobic. The final product after dewatering was subjected to pyrolysis and gasification. The gases obtained were characterised by a high heat of combustion of about 11-15 MJ Nm(-3). PMID:11640982

Krzystek, L; Ledakowicz, S; Kahle, H J; Kaczorek, K

2001-12-28

345

Performance evaluation\\/analysis of Pakistan Research Reactor1 (PARR1) current core configuration  

Microsoft Academic Search

Neutronic and thermal hydraulic analyses have been carried out for current core of Pakistan Research Reactor-1 (PARR-1). Comparison was made between calculated and measured key neutronic parameters. Reactor core parameters important for reactor operation and safety have been calculated. Calculated neutronic parameters include: excess reactivity, shut down margin, control rod worth, peak power density location, criticality position, peaking factors, neutron

Tayyab Mahmood; Ishtiaq Hussain Bokhari; Masood Iqbal; Tariq Mahmood; Naseer Ahmed; Muhammad Israr

2011-01-01

346

On-line dynamic optimization and control strategy for improving the performance of batch reactors  

Microsoft Academic Search

Since batch reactors are generally applied to produce a wide variety of specialty products, there is a great deal of interest to enhance batch operation to achieve high quality and purity product while minimizing the conversion of undesired by-product. The use of process optimization in the control of batch reactors presents a useful tool for operating batch reactors efficiently and

A. Arpornwichanop; P. Kittisupakorn; I. M. Mujtaba

2005-01-01

347

Performance characteristics of the high power density, flux-conserving tokamak \\/FCT\\/ reactor  

Microsoft Academic Search

Most of the fusion Experimental Power Reactor (EPR) and commercial power reactor designs have been limited to low beta (ratio of plasma pressure to magnetic field pressure), low power density tokamak systems. In an effort to redesign a viable, economically attractive power reactor that could meet the electric utilities needs, the flux-conserving tokamak concept has emerged as a leading contender.

S. K. Borowski; T. Kammash

1979-01-01

348

A comparison of the performance of compact neutrino detector designs for nuclear reactor safeguards and monitoring.  

SciTech Connect

There has been an increasing interest in the monitoring of nuclear fuel for power reactors by detecting the anti-neutrinos produced during operation. Small liquid scintillator detectors have already demonstrated sensitivity to operational power levels, but more sensitive monitoring requires improvements in the efficiency and uniformity of these detectors. In this work, we use a montecarlo simulation to investigate the detector performance of four different detector configurations. Based on the analysis of neutron detection efficiency and positron energy response, we find that the optimal detector design will depend on the goals and restrictions of the specific installation or application. We have attempted to present the relevant information so that future detector development can proceed in a profitable direction.

Reyna, D. E.; McKeown, R. W.; High Energy Physics; Drexel Univ.

2006-10-27

349

Theoretical model for the performance of bubble-column reactors used for Fischer-Tropsch synthesis  

SciTech Connect

A theoretical model is presented for describing the performance of bubble-column reactors used for Fischer-Tropsch synthesis. The model accounts for axial dispersion in both the gas and liquid phases, and for non-uniform distribution of catalyst. The influence of H/sub 2/ and CO concentrations in the liquid phase on the stoichiometry and kinetics of the synthesis and water-gas-shift reactions are treated rigorously. Calculations have been carried out to illustrate the influence of transport parameters on syngas conversion and axial distribution of reactants and products. Comparisons are also made with recently reported experimental results, to demonstrate the capability of the model to predict the dependence of the syngas conversion and H/sub 2/-CO consumption ratio on feed composition and velocity. 28 references, 13 figures, 2 tables.

Stern, D.; Bell, A.T.; Heinemann, H.

1985-01-01

350

Robustness of the microaerobic removal of hydrogen sulfide from biogas.  

PubMed

Several disturbances presented in full-scale digesters can potentially affect the efficiency of the microaerobic removal process. This study evaluates the variation of the sulfur load and the performance of the system in situations of oxygen lack or excess and after normal rates are recovered. The process was shown to recover from oxygen lack or excess within 28 h when the original conditions were restored in a pilot-plant digester of 200 L treating sewage sludge with HRT of 20 days. The decrease of the sulfur load to the digester did not affect the biogas composition in the short-term and when oxygen rate was reduced to adjust to the lower hydrogen sulfide production, the removal proceeded normally with a lower unemployed oxygen amount. The digester opening to remove accumulated sulfur in the headspace did not alter process performance once the microaerobic removal was restarted. PMID:22466581

Díaz, I; Fdz-Polanco, M

2012-01-01

351

A technoeconomic assessment of solar-assisted biogas systems  

SciTech Connect

Biogas has been recognized as one of the best available renewable and decentralized sources of energy and organic fertilizer for a country like India. There is enough evidence to prove that temperature has a profound influence on the rate of biogas production. In temperate climates, where the winters are mild, solar energy systems can be effectively used to increase the temperature of the biogas digester to the desired level. This paper examines various techniques, such as a solar greenhouse on the biogas digester, a shallow solar pond water heater, insulation, and a heat exchanger, and their technoeconomic viability.

Bansal, N.K. (Centre of Energy Studies Indian Institute of Technology, Delhi Hauz Khas, New Delhi-110016 (IN))

1988-01-01

352

Techno-socio-economic study of bio-gas plants  

SciTech Connect

This study covers technological, social and economic aspects of the biogas program in Chitawan, Nepal. Many interesting facts are revealed which may be useful for future planning of Nepalese biogas programs. Concerning the social aspects, only big farmers (having more than 4 bighas of land and more than 10 domestic animals) were found to have biogas plants. No farmer who had a biogas plant was illiterate. As for the technical aspects of the total gas ovens used in the area, 66% were of BTI design. Most of the ovens were of 0.45-m/sup 3/ capacity. The life of BTI ovens was found to be shorter than the life of ovens of other companies. BTI ovens are not useful when farmers have to use a big pot for cooking. All farmers of the area were found to be convinced of the utility of the biogas plant. With regard to the economic aspects of using biogas plants, farmers were able to save 53% of the total expenditure which they had been spending for fuel. Wood consumption was reduced to 50% by using biogas. The internal rate of return of a 2.8-m/sup 3/ biogas plant was found to be 14% assuming that the plant would last for 20 years. Most of the farmers in the area did not have biogas plants. The main reason given was that there were not enough capital and cattle to begin such an operation.

Not Available

1981-01-01

353

Biogas as a source of rural energy  

SciTech Connect

The hilly state of Himachal Pradesh, with nearly 2.15 million cattle and 0.7 million buffalo, has the potential to install 0.64 million biogas plants of 1 m{sup 3} size. These plants could generate nearly 4.90 x 105 m{sup 3} of biogas, equivalent to 3.07 x 10{sup 5} L kerosene per day to meet domestic energy needs of nearly one-fourth of its rural population. During 1982--1998, only 12.8% of this potential was achieved. The percent of possible potential achieved in plant installations in 12 districts of this state, namely, Bilaspur, Chamba, Hamirpur, Kangra, Kinnaur, Kullu, Lahul-Spiti, Mandi, Shimla, Sirmour, Solan, and Una, are 35.35, 1.70, 20.96, 8.67, 1.54, 6.96, 0.00, 18.49, 3.84, 8.521, 18.29, and 13.23%, respectively. There is a need to strengthen biogas promotion, particularly in the districts of Kangra, Mandi, Solan, and Una, which range from mid-hill to low-hill terrain and which have large potential due to high concentration of bovine population. Increased costs and comparatively low rate of subsidies has resulted in a decreasing rate of plant installation annually, from 3,500 during 1987--1992 to fewer than 1,200 during 1995--1998. The percentage of functioning plants was 82% in 1987--1988 but has decreased to 63%. To ensure proper installation and functionality of plants, the authors discuss the needed improvements in the biogas promotion program.

Kalia, A.K.

2000-01-01

354

Biogas production: current state and perspectives  

Microsoft Academic Search

Anaerobic digestion of energy crops, residues, and wastes is of increasing interest in order to reduce the greenhouse gas\\u000a emissions and to facilitate a sustainable development of energy supply. Production of biogas provides a versatile carrier\\u000a of renewable energy, as methane can be used for replacement of fossil fuels in both heat and power generation and as a vehicle\\u000a fuel.

Peter Weiland

2010-01-01

355

The impact of ENDF/B-V fission spectrum parameter uncertainty on the prediction of fast reactor burnup performance  

SciTech Connect

The sensitivity and uncertainty of various core burnup performance quantities (e.g., k[sub eff], burnup reactivity swing, local power density, etc.) to the heavy isotope fission spectrum parameters was investigated using depletion perturbation methods and ENDF/B-V covariance data. A brief description of the methods is followed by results of a 900-MW(thermal) fast reactor. The analysis here indicates that for a 900-MW(thermal) heterogeneous fast reactor, the experimental error in the ENDF/B-V fission spectrum parameters does not have a major impact on calculational uncertainty in the core burnup performance.

Downar, T.J.; Broda, J.; Kritzer, J. (Purdue Univ., Lafayette, IN (United States))

1990-01-01

356

Treatment of wastewater from coffee bean processing in anaerobic fixed bed reactors with different support materials: performance and kinetic modeling.  

PubMed

An evaluation was performed of three upflow anaerobic fixed bed reactors for the treatment of wastewater from coffee bean processing (WCP). The supports used were: blast furnace cinders, polyurethane foam and crushed stone with porosities of 53, 95 and 48%, respectively. The testing of these 139.5 L reactors consisted of increasing the COD of the influent (978; 2401 and 4545 mg L(-1)), while maintaining the retention time of 1.3 days. For the maximum COD applied, the reactor filled with foam presented removals of 80% (non-filtered samples) and 83% (filtered samples). The greater performance of the reactor filled with foam is attributed to its porosity, which promoted greater collection of biomass. From the results, it could be concluded that the reactors presented satisfactory performance, especially when using the foam as a support. Furthermore, the modified Stover-Kincannon and second order for multicomponent substrate degradation models were successfully used to develop a model of the experimental data. PMID:22609965

Fia, Fátima R L; Matos, Antonio T; Borges, Alisson C; Fia, Ronaldo; Cecon, Paulo R

2012-05-18

357

Biogas production potential and kinetics of microwave and conventional thermal pretreatment of grass.  

PubMed

Pretreatment methods play an important role in the improvement of biogas production from the anaerobic digestion of energy grass. In this study, conventional thermal and microwave methods were performed on raw material, namely, Pennisetum hybrid, to analyze the effect of pretreatment on anaerobic digestion by the calculation of performance parameters using Logistic function, modified Gompertz equation, and transference function. Results indicated that thermal pretreatment improved the biogas production of Pennisetum hybrid, whereas microwave method had an adverse effect on the performance. All the models fit the experimental data with R (2)?>?0.980, and the Reaction Curve presented the best agreement in the fitting process. Conventional thermal pretreatment showed an increasing effect on maximum production rate and total methane produced, with an improvement of around 7% and 8%, respectively. With regard to microwave pretreatment, maximum production rate and total methane produced decreased by 18% and 12%, respectively. PMID:22205322

Li, Lianhua; Kong, Xiaoying; Yang, Fuyu; Li, Dong; Yuan, Zhenhong; Sun, Yongming

2011-12-29

358

Design and scale-up of an oxidative scrubbing process for the selective removal of hydrogen sulfide from biogas.  

PubMed

Reliable and selective removal of hydrogen sulfide (H(2)S) is an essential part of the biogas upgrading procedure in order to obtain a marketable and competitive natural gas substitute for flexible utilization. A promising biogas desulfurization technology has to ensure high separation efficiency regardless of process conditions or H(2)S load without the use or production of toxic or ecologically harmful substances. Alkaline oxidative scrubbing is an interesting alternative to existing desulfurization technologies and is investigated in this work. In experiments on a stirred tank reactor and a continuous scrubbing column in laboratory-scale, H(2)S was absorbed from a gas stream containing large amounts of carbon dioxide (CO(2)) into an aqueous solution prepared from sodium hydroxide (NaOH), sodium bicarbonate (NaHCO(3)) and hydrogen peroxide (H(2)O(2)). The influence of pH, redox potential and solution aging on the absorption efficiency and the consumption of chemicals was investigated. Because of the irreversible oxidation reactions of dissolved H(2)S with H(2)O(2), high H(2)S removal efficiencies were achieved while the CO(2) absorption was kept low. At an existing biogas upgrading plant an industrial-scale pilot scrubber was constructed, which efficiently desulfurizes 180m(3)/h of raw biogas with an average removal efficiency of 97%, even at relatively high and strongly fluctuating H(2)S contents in the crude gas. PMID:22440540

Krischan, J; Makaruk, A; Harasek, M

2012-02-18

359

Pilot project of biogas production from pig manure and urine mixture at ambient temperature in Ventanilla (Lima, Peru).  

PubMed

Parque Porcino de Ventanilla has an extension of 840ha with 2200 farmers dedicated to pig production. There is a lack of services in the area (i.e., water supply, electricity, or waste collection). Anaerobic treatment of pig manure would replace current dumping and incineration, reducing environmental pollution and hazards to public health, as well as providing an organic fertilizer and biogas. The objective of the present work was to study the viability of ambient temperature anaerobic digestion of pig manure diluted in urine, by means of on-site pilot scale reactors. The final goal was to establish design parameters for anaerobic digesters to be implemented; since it was part of a project to improve life conditions for the farmers through the incorporation of better management techniques. Experiments were carried out in a low-cost pilot plant, which consists of three anaerobic digesters (225L total volume), without heating or agitation, placed in a greenhouse. The start-up of the digestion process was performed with a mixture of temperature adapted pig manure-sludge and fresh rumen, and showed a good performance regardless of the dilution of pig manure with water or urine, which is a key parameter due to the scarcity of water in the area under study. PMID:18417337

Ferrer, I; Gamiz, M; Almeida, M; Ruiz, A

2008-04-15

360

Performance analysis of the intense slow-positron beam at the NC State University PULSTAR reactor  

NASA Astrophysics Data System (ADS)

An intense positron beam, for application in nanophase characterization, is now under construction at the 1 MW PULSTAR nuclear reactor at North Carolina State University (NCSU). A tungsten converter/moderator is used, allowing positrons to be emitted from the surface with energies of a few electron volts. These slow positrons will be extracted from the moderator and formed into a beam by electrostatic lenses and then injected into a solenoidal magnetic field for transport to one of three experimental stations, via a beam switch. To optimize the performance of the beam and to predict the slow-positron intensity, a series of simulations were performed. A specialized Monte-Carlo routine was integrated into the charged-particle transport calculations to allow accounting for the probabilities of positron re-emission and backscattering from multiple-bank moderator/converter configurations. The results indicate that either a two-bank or a four-bank tungsten moderator/converter system is preferred for the final beam design. The predicted slow-positron beam intensities range from nearly 7×108 to 9×108e+/s for the two-bank and the four-bank systems, respectively.

Moxom, J.; Hathaway, A. G.; Bodnaruk, E. W.; Hawari, A. I.; Xu, J.

2007-08-01

361

High performance inboard shield design for the compact TIBER-II test reactor: Appendix A-2  

SciTech Connect

The compactness of the TIBER-II reactor has placed a premium on the design of a high performance inboard shield to protect the inner legs of the toroidal field (TF) coils. The available space for shield is constrained to 48 cm and the use of tungsten is mandatory to protect the magnet against the 1.53 MW/m/sup 2/ neutron wall loading. The primary requirement for the shield is to limit the fast neutron fluence to 10/sup 19/ n/cm/sup 2/. In an optimization study, the performance of various candidate materials for protecting the magnet was examined. The optimum shield consists of a 40 cm thick W layer, followed by an 8 cm thick H/sub 2/O/LiNO/sub 3/ layer. The mechanical design of the shield calls for tungsten blocks within SS stiffened panels. All the coolant channels are vertical with more of them in the front where there is a high heat load. The coolant pressure is 0.2 MPa and the maximum structural surface temperature is <95/sup 0/C. The effects of the detailed mechanical design of the shield and the assembly gaps between the shield sectors on the damage in the magnet were analyzed and peaking factors of approx.2 were found at the hot spots. 2 refs., 6 figs., 2 tabs.

El-Guebaly, L.A.; Sviatoslavsky, I.N.

1987-01-01

362

Effect of corrosion of steel elements on the treatment of dairy wastewater in a UASB reactor.  

PubMed

Experiments were performed in parallel using two laboratory upflow anaerobic sludge blanket (UASB) reactors. One of the two reactors was packed with spiral elements made of steel wire with 48% iron content in order to examine the influence of the steel elements on the chemical oxygen demand (COD) and efficiency of phosphorus removal from synthetically prepared dairy wastewater. A strong relationship was found between anaerobic corrosion and efficiency of phosphorus removal. Phosphorus removal in the reactor packed with steel elements was between 16.4% and 64.4% higher than without the steel elements present. The anaerobic corrosion process improved COD removal efficiency by 1.0-3.1%, which was statistically significant. When steel elements were present the methane content of the biogas was increased by 6.7%. Increasing the organic loading rate had a strong effect on the anaerobic efficiency of the dairy wastewater treatment. PMID:20540419

J?drzejewska Cici?ska, M; Krzemieniewski, M

2010-05-01

363

On performing experimental studies on transient states of continuous-flow methanogenic reactors.  

PubMed

One approach to exploring the behavior of microbial cultures during transient conditions of unbalanced growth is to experimentally observe continuous-flow biological reactors which have been subjected to perturbations in the influent flowrate and/or concentration of growth-limiting substrate. Proper interpretation of such experiments requires that appropriate account be taken of reaction stoichiometry, the distribution and abundance of microbial populations within the reactor, and the nonideality of mixing and flow distribution in the reactor. These aspects of proper experimental design are particularly critical when the system of interest involves methanogenic consortia and is not a completely-mixed, suspended-growth reactor. PMID:18592572

DeLorme, A J; Kapuscinski, R B

1990-03-25

364

Biogas Production from the Organic Fraction of Municipal Solid Waste  

Microsoft Academic Search

This article discusses the potential use of biogas from municipal landfills to fuel urban heat space in Turkey. Biogas can be obtained from digesting the organic material of municipal solid wastes (MSW). The composition of MSW varies by the source of waste; however, in all cases the major constituents of MSW are organic in nature and the organics account for

Ayhan Demirbas

2006-01-01

365

Concentrated biogas slurry enhanced soil fertility and tomato quality  

Microsoft Academic Search

Biogas slurry is a cheap source of plant nutrients and can offer extra benefits to soil fertility and fruit quality. However, its current utilization mode and low content of active ingredients limit its further development. In this paper, a one-growing-season field study was conducted to assess the effects of concentrated biogas slurry on soil property, tomato fruit quality, and composition

Fang-Bo Yu; Xi-Ping Luo; Cheng-Fang Song; Miao-Xian Zhang; Sheng-Dao Shan

2010-01-01

366

Bioenergy from permanent grassland – A review: 1. Biogas  

Microsoft Academic Search

Grassland biomass is suitable in numerous ways for producing energy. It is well established as feedstock for biogas production. The aim of this review is to summarize current knowledge on suitability and sustainability of grassland biomass for anaerobic digestion. In the first section grassland management for biogas feedstock as well as specifics of harvest, postharvest and digestion technology are described.

A. Prochnow; M. Heiermann; M. Plöchl; B. Linke; C. Idler; T. Amon; P. J. Hobbs

2009-01-01

367

Electric energy generation from landfill biogas — Case study and barriers  

Microsoft Academic Search

Biogas, formed from degradation of organic matters, is composed by a mixture of gases, the main components being carbon dioxide (CO2) and methane (CH4), which is a greenhouse gas with global warming potential 20 times greater compared to CO2. The production of biogas is possible from the degradation of organic matters, like urban solid waste, waste from agricultural and cattle

V. P. Garcilasso; S. M. S. G. Velazquez; S. T. Coelho; L. S. Silva

2011-01-01

368

Life cycle assessment of biogas digestate processing technologies  

Microsoft Academic Search

Driven by a high increase of large scale biogas plants based on bio waste, agricultural by-products and waste from food industry, there is a rapid structural development of the agricultural holdings in Germany. Particularly in regions with intensive livestock husbandry, this leads to an overprovision of nutrients. New technologies have been introduced during the last years to treat biogas digestate

T. Rehl; J. Müller

2011-01-01

369

Continuous process monitoring for biogas plants using microwave sensors  

Microsoft Academic Search

The efficiency of biogas production during anaerobic digestion depends heavily on optimal dosing ratios and stable operations which can not be achieved without accurate and reliable monitoring and control of the dry matter (DM) and organic dry matter (oDM) content. The materials in biogas processes to be measured are either stored in a vessel flowing in a pipe, either as

T. Nacke; A. Barthel; C. Pflieger; U. Pliquett; D. Beckmann; A. Goller

2010-01-01

370

Crop residue conversion to biogas by dry fermentation  

SciTech Connect

A simple 'dry fermentation' process has been developed that may enable economical conversion of drier crop residues to biogas. Results from two years of process definition and scale-up to a 110 m/sup 3/ prototype show that biogas production rates exceeding those necessary to make the dry fermentor competitive have been achieved. 13 refs.

Jewell, W.J.; Dell'Orto, S.; Fanfoni, K.J.; Fast, S.J.; Jackson, D.A.; Kabrick, R.M.; Gottung, E.J.

1981-01-01

371

Potential of domestic biogas digester slurry in vermitechnology  

Microsoft Academic Search

This work illustrates the potential of domestic biogas digester slurry in vermicompost production. To achieve the objectives biogas plant slurry (BGS) was mixed with crop residues (CR) in different ratios to produce seven different feed mixtures for earthworm Eisenia fetida. After 15weeks vermicomposted material was analyzed for different chemical parameters. In all waste mixtures, a decrease in pH, organic C

Surindra Suthar

2010-01-01

372

A Technoeconomic Assessment of Solar-Assisted Biogas Systems  

Microsoft Academic Search

Biogas has been recognized as one of the best available renewable and decentralized sources of energy and organic fertilizer for a country like India. There is enough evidence to prove that temperature has a profound influence on the rate of biogas production. In temperate climates, where the winters are mild, solar energy systems can be effectively used to increase the

N. K. BANSAL

1988-01-01

373

Small biogas plant: its construction, operation and use  

Microsoft Academic Search

This booklet has been prepared to help interested parties design and operate small biogas plants. It is written in relatively simple language, understandable to people with limited scientific and technical training and it takes a practical approach. Because of the pressing demand for food, more fertilizer is needed to raise more crops, but supply is getting less. With a biogas

F. D. Sr. Maramba; E. D. Obias; C. Taganas

1977-01-01

374

POTENTIAL OF BIOGAS PRODUCTION IN SUSTAINABLE BIOREFINERY CONCEPTS  

Microsoft Academic Search

Currently, biogas production is mainly based on the anaerobic digestion of single energy crops. In the future, biogas production from energy crops will increase and will have to be based on a wide range of energy crops that are grown in versatile, sustainable crop rotations. In addition, more by-products products from the agricultural, food and energy industry need to be

Alexander Bauer; Regina Hrbek; Barbara Amon; Vitaliy Kryvoruchko; Vitomir Bodiroza; Helmut Wagentristl; Werner Zollitsch; Bettina Liebmanne; Martin Pfeffere; Anton Friedle; Thomas Amon

375

Feasibility Study of Biogas Production from Energy Crops.  

National Technical Information Service (NTIS)

Sweden has a great need for alternatives to traditional agricultural cultivation. In many countries, there has over the past ten years been a great interest in biogas production from energy crops. Biogas may be used in many different ways: * Direct combus...

L. Brolin L. Thyselius M. Johansson

1988-01-01

376

DRY NONHEATED ANAEROBIC BIOGAS FERMENTATION USING AGED BEEF CATTLE MANURE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Biogas production at beef cattle feedlots is hard to justify because of the large amounts of dilution water required and the high cost to design and operate conventional water-based digestion systems. Laboratory and field experiments were conducted to determine the feasibility of producing biogas us...

377

Technical–economical analysis of the Saveh biogas power plant  

Microsoft Academic Search

The resource limitation of fossil fuels and the problems arising from their combustion has led to widespread research on the accessibility of new and renewable energy resources. Solar, wind, thermal and hydro sources, and finally biogas are among these renewable energy resources. But what makes biogas distinct from other renewable energies is its importance in controlling and collecting organic waste

Giti Taleghani; Akbar Shabani Kia

2005-01-01

378

An Introduction to Biogas Production on the Farm.  

ERIC Educational Resources Information Center

|This three-section report provides introductory information about biogas production and its application to farm environments. The first section discusses the various components of a biogas production system (a system that converts organic wastes into a usable form of energy), explains the system's benefits and liabilities, and provides a brief…

National Center for Appropriate Technology, Butte, MT.

379

Biogas Potential on Long Island, New York: A Quantification Study  

SciTech Connect

Biogas is the product of anaerobic digestion of waste, whether occurring spontaneously in landfills or under controlled conditions in digesters. Biogas is viewed as an important energy source in current efforts to reduce the use of fossil fuels and dependency on imported resources. Several studies on the assessment of biogas potential have been made at regional, national, and global scales. However, because it is not economically feasible to transport biogas feedstock over long distances, it is more appropriate to consider local waste sources for their potential to produce biogas. An assessment of the biogas potential on Long Island, based on the review of local landfills, wastewater treatment plants, solid waste generation and management, and agricultural waste, found that 234 x 10{sup 6} m{sup 3} of methane (CH{sub 4}) from biogas might be harvestable, although substantial barriers for complete exploitation exist. This number is equivalent to 2.52 TW-h of electricity, approximately 12% of fossil fuel power generation on Long Island. This work can serve as a template for other areas to rapidly create or approximate biogas potentials, especially for suburban U.S. locations that are not usually thought of as sources of renewable energy.

Mahajan, D.; Patel, S.; Tonjes, D.

2011-08-25

380

Energy Generation by a Renewable Source - Sewage Biogas  

Microsoft Academic Search

This article will present two projects related to energy generation using sewage biogas as fuel and different engines, one is a Otto cycle engine and the other is a microturbine. The first one had as project proposal the sewage biogas use as fuel in an 18 kva Otto cycle generator, to produce electric energy, which development was a commitment of

Sílvia Maria Stortini González; Orlando Cristiano; Osvaldo Stella Martins; Fernando Castro

381

Plug flow digestors for biogas generation from leaf biomass  

Microsoft Academic Search

The low, family level availability of animal dung in rural Indian families restricts the spread of biogas technology. This has warranted the design and development of novel biogas plants for other biomass feedstocks. The plug-flow digestors discussed in this paper circumvent the problems associated with floating of biomass feedstocks and enable a semi-continuous operation. The long term operation of such

K. S Jagadish; H. N Chanakya; P Rajabapaiah; V Anand

1998-01-01

382

Determination of Acetylcholine and Choline in Human Plasma Using High-Performance Liquid Chromatography Combined with an Immobilized Enzyme Reactor  

Microsoft Academic Search

A method for assaying Acetylcholine (ACh) and Chloine (Ch) simultaneously in human plasma by high-performance liquid chromatography with electrochemical detection (LCEC) combined with an immobilized enzyme reactor is described for the first time in this paper. Human plasma samples were obtained from 12 volunteers free of neurological and psychological disease. The volunteers were from 22 to 41 years old (mean

Y. Fujiki; Y. Ikeda; S. Okuyama; K. Tomoda; K. Ooshiro; T. Itoh; T. Yamauchi; H. Matsumura

1990-01-01

383

Enhanced performance of deuterium-tritium-fueled supershots using extensive lithium conditioning in the Tokamak Fusion Test Reactor  

Microsoft Academic Search

In the Tokamak Fusion Test Reactor (TFTR) [K. M. McGuire etal., Phys. Plasmas 2, 2176 (1995)] a substantial improvement in fusion performance has been realized by combining the enhanced confinement due to tritium fueling with the enhanced confinement due to extensive conditioning of the limiter with lithium. This combination has resulted in not only significantly higher global energy confinement times

D. K. Mansfield; J. D. Strachan; M. G. Bell; S. D. Scott; R. Budny; E. S. Marmar; J. A. Snipes; J. L. Terry; S. Batha; R. E. Bell; M. Bitter; C. E. Bush; Z. Chang; D. S. Darrow; D. Ernst; B. Grek; H. W. Herrmann; K. W. Hill; A. Janos; D. L. Jassby; F. C. Jobes; D. W. Johnson; L. C. Johnson; F. W. Levinton; D. R. Mikkelsen; D. Mueller; D. K. Owens; A. L. Roquemore; C. H. Skinner; T. Stevenson; B. C. Stratton; E. Synakowski; G. Taylor; A. von Halle; S. von Goeler; K. L. Wong; S. J. Zweben

1995-01-01

384

Performance of ferritic alloy cladding in LMR (liquid metal reactor) mixed-oxide fuel pins in EBR-II  

Microsoft Academic Search

Mixed uranium-plutonium oxide fuel pins with candidate ferritic alloy cladding have been irradiated in the EBR-II to evaluate performance for possible Liquid Metal Reactor (LMR) application. Ferritic alloys are of considerable interest in LMR's because of their resistance to irradiation induced swelling which, in the case of austenitic alloys, has led to duct dimensional changes and interactions between the duct

B. J. Makenas; L. A. Lawrence

1986-01-01

385

Preliminary experimental results of Sewage Sludge (SS) Co-digestion with Palm Oil Mill Effluent (POME) for Enhanced Biogas Production in Laboratory Scale Anaerobic Digester  

NASA Astrophysics Data System (ADS)

An investigation on the feasibility of co-digesting Sewage Sludge with Palm Oil Mill Effluent for enhancing the biogas production and the corresponding effect of the co-digestion substrate ratio on the biogas production has been evaluated. Anaerobic co-digestion of POME with SS was performed at ratios of 100:0, 70:30, 60:40 and 0:100 to find the optimum blend required for enhanced waste digestion and biogas production. Single stage batch digestion was carried out for 12 days in a laboratory scale anaerobic digester. Co-digestion of sludge's at the 70:30 proportion resulted in optimal COD and C: N ratio which subsequently recorded the highest performance with regards to biogas production at 28.1 L's compared to the 1.98 L's of biogas produced from digestion of SS alone. From the results obtained, it is evident that co-digestion of POME and SS is an attractive option to be explored for enhancement of biogas production in anaerobic digesters.

Sivasankari, R.; Kumaran, P.; Normanbhay, Saifuddin; Halim Shamsuddin, Abd

2013-06-01

386

Hydraulic performance of a proposed in situ photocatalytic reactor for degradation of MTBE in water  

Microsoft Academic Search

Methyl tert-butyl ether (MTBE) groundwater remediation projects often require a combination of technologies resulting in increasing the project costs. A cost-effective in situ photocatalytic reactor design, Honeycomb II, is proposed and tested for its efficiency in MTBE degradation at various flows. This study is an intermediate phase of the research in developing an in situ photocatalytic reactor for groundwater remediation.

Leonard Lik Pueh Lim; Rod Lynch

2011-01-01

387

Three pass core design proposal for a high performance light water reactor  

Microsoft Academic Search

The paper describes a novel core concept for a nuclear reactor cooled with supercritical water, in which the coolant is heated up from 280°C at the reactor inlet to 500°C at the outlet in four steps: a first heat-up step is provided by heat transfer from fuel assemblies to the moderator water in gaps and moderator boxes, a second step

T. Schulenberg; J. Starflinger; J. Heinecke

2008-01-01

388

Coal liquefaction: Investigation of reactor performance, role of catalysts and PCT properties: Final report  

Microsoft Academic Search

In the first section of this report, a mathematical model for the Wilsonville Integrated Two-Stage Liquefaction Process is presented. The first stage is a bubble column slurry reactor and has been modeled previously. The second stage is an ebullated bed catalytic reactor designed to improve product quality, process flexibility, and hydrogen utilization efficiency. The basic equations for the second stage

Y. Shah; J. Tierney; I. Wender; S. Joseph; C. Wen

1987-01-01

389

Design and Initial Performance of the Sandia Pulsed Reactor-III.  

National Technical Information Service (NTIS)

The Sandia Pulsed Reactor-III (SPR-III) is a new fast pulsed reactor which has recently undergone initial testing at Sandia Laboratories. SPR-III is a uranium-10 weight percent molybdenum fuel assembly with a 17.78 cm irradiation cavity similar in design ...

J. A. Reuscher B. F. Estes

1976-01-01

390

Effect of long-term idle periods on the performance of sequencing batch reactors  

Microsoft Academic Search

Abstract Sludge storage can be used,as an effective control handle to adjust plant capacity to large influent variations. The sequencing batch reactor (SBR) technology is well suited for temporary sludge storage because reactors can easily be switched,off individually and operated in an idle mode. In this study experimental results on the effect of long term (weeks) idle periods on nitrogen

E. morgenroth; A. Obermayer; E. Arnold; A. Brühl; M. Wagner; P. a. Wilderer

391

Innovative fusion reactor design analysis: Annual performance report, May 15, 1988--January 31, 1989  

SciTech Connect

This report discusses the following topics on fusion reactor component design: FLiBe intermediate heat exchanger design analysis; FLiBe properties; design methodology; FLiBe system steam generator freezeup; FLiBe reactor systems studies; tritium breeding ratio control; analysis of original objectives; and budget analysis. 15 refs., 13 figs., 3 tabs. (LSP)

Klein, A.C.

1989-01-31

392

Performance evaluation of nonthermal plasma reactors for NO oxidation in diesel engine exhaust gas treatment  

Microsoft Academic Search

The discharge plasma-chemical hybrid process for NOx removal from the due gas emissions is an extremely effective and economical approach in comparison with the conventional selective catalytic reduction system. In this paper we bring out a relative comparison of several discharge plasma reactors from the point of NO removal efficiency. The reactors were either energized by AC or by repetitive

T. Yamamoto; B. S. Rajanikanth; M. Okubo; T. Kuroki; M. Nishino

2001-01-01

393

A built-in zero valent iron anaerobic reactor to enhance treatment of azo dye wastewater.  

PubMed

Waste scrap iron was packed into an upflow anaerobic sludge blanket (UASB) reactor to form a zero valent iron (ZVI) - UASB reactor system for treatment of azo dye wastewater. The ZVI acted as a reductant to decrease ORP in the reactor by more than 40 mv and functioned as an acid buffer to increase the pH in the reactor from 5.44 to 6.29, both of which improved the performance of the anaerobic reactor. As a result, the removal of color and COD in this reactor was 91.7% and 53%, respectively, which was significantly higher than that of a reference UASB reactor without ZVI. The UV-visible spectrum demonstrated that absorption bands of the azo dye from the ZVI-UASB reactor were substantially reduced. The ZVI promoted methanogenesis, which was confirmed by an increase in CH(4) content in the biogas from 47.9% to 64.8%. The ZVI bed was protected well from rusting, which allowed it to function stably. The effluent could be further purified only by pH adjustment because the Fe(2+) released from ZVI served as a flocculent. PMID:21330722

Zhang, Yaobin; Jing, Yanwen; Quan, Xie; Liu, Yiwen; Onu, Pascal

2011-01-01

394

Two-phase pump performance program preliminary test plan. Key phase report. [Water cooled reactor coolant loss transients  

SciTech Connect

A preliminary test plan designed to provide basic data on the reactor coolant recirculation pump performance under two-phase flow LOCA conditions is described. The basic objectives of this program are to: (a) Obtain sufficient steady-state and transient two-phase empirical data to substantiate, and ultimately improve, the mathematical model of the reactor recirculation pump presently used for LOCA analysis; and (b) Obtain sufficient data on pump overspeed characteristics under transient two-phase blowdown conditions to verify the pump flywheel integrity to satisfy the requirements of the AEC Regulatory Guide No. 1.14. (GRA)

Dixson, D.L.; Kennedy, W.G.; Jacob, M.C.; Shuckrow, J.R.

1975-09-01

395

Solar photocatalytic degradation of commercial textile azo dyes: Performance of pilot plant scale thin film fixed-bed reactor  

Microsoft Academic Search

Performances of solar photocatalytic pilot plant using TiO2-P25 (Degussa) were investigated for removal of commercial azo dye chosen as model compound. Experiments were carried out to optimize various parameters, influencing the performance of the operated thin-film fixed-bed reactor (TFFBR) with an area of 25 m2. The results showed kinetic dependency on flow rate, catalyst loading, and initial dye concentration. The

Ghanem Zayani; Latifa Bousselmi; Farouk Mhenni; Ahmed Ghrabi

2009-01-01

396

Biogas Production from Acid Cheese Whey Using a Two-Stage Digester  

Microsoft Academic Search

A two-stage, no-mix anaerobic digester of 155 l capacity was used to investigate the feasibility of biogas production and the pollution potential reduction of acid cheese whey. The digester was operated at a 15-day hydraulic retention time and three temperatures (19, 25, 35°C). Both the temperature and pH of the whey had significant effects on the performance of the digester.

A. E. GHALY

1989-01-01

397

Comparison of chemical and biological pretreatment of corn straw for biogas production by anaerobic digestion  

Microsoft Academic Search

In this work, the effects of corn straw pretreatments using Fungus Pleurotus florida and chemicals such as NaOH, ammonia, and urea on the biogasification performance by anaerobic digestion were compared. A laboratory-scale, single-phase and continuous anaerobic biogas digester was used for the evaluation. It was found that after different treatments, the compositional contents of corn straw such as lignin, cellulose,

Weizhang Zhong; Zhongzhi Zhang; Wei Qiao; Pengcheng Fu; Man Liu

2011-01-01

398

An approach to improve methanogenesis through the use of mixed cultures isolated from biogas digester  

Microsoft Academic Search

Biogas production has been shown to be inhibited by branched chain fatty acids (isobutyric, isovaleric) produced in the digester\\u000a by cellulolytic organisms. Performance of these mixed cellulolytic cultures isolated at 25°C (C25) and at 35° (C35) in a batch digester using cattle manure confirmed that C35, which forms mainly straight chain fatty acids from cellulose was more suitable for use

G. P. Kalle; Kalpana K. Nayak; Christina De Sa

1985-01-01

399

Environmental assessment of biogas co- or tri-generation units by life cycle analysis methodology  

Microsoft Academic Search

A life cycle analysis performed on biogas co- or tri-generation units shows that the environmental impact depends on the fraction of heat (or cold) used, the distance for crops collection, the efficiencies of the unit and on the NOx emissions. A high efficiency unit (?el=0.4 and ?g=0.8) and low NOx content (80mg\\/Nm3) based on 20km crops collection will save CO2

C. Chevalier; F. Meunier

2005-01-01

400

Improvement of a grass-clover silage-fed biogas process by the addition of cobalt  

Microsoft Academic Search

Batch assays were performed with samples from a silage-fed mesophilic biogas process accumulating acetate to examine if the addition of single trace elements (iron, nickel, cobalt and molybdenum) or a mixture of trace elements could improve the process. The results from the batch assays led to the addition of cobalt to reach a concentration of 0.2 mg L?1. This made

Å. Jarvis; Å. Nordberg; T. Jarlsvik; B. Mathisen; B. H. Svensson

1997-01-01

401

Process flow model of solid oxide fuel cell system supplied with sewage biogas  

Microsoft Academic Search

A model for a 100kW class solid oxide fuel cell (SOFC) system running on biogas from a sewage sludge digestion plant was implemented in a process flow scheme using external steam reforming. The model stack consisted of planar anode supported cells operated at 800°C displaying state-of-the-art electrochemical performance (0.15W\\/cm2 at 80% fuel utilisation). Real annual data from an existing sewage

J Van herle; F Maréchal; S Leuenberger; Y Membrez; O Bucheli; D Favrat

2004-01-01

402

Implication of Biogas Potential in Thailand: The Case Study of Livestock Farm  

Microsoft Academic Search

Nowadays, in Thailand biogas digester is the popular project of livestock farms to invest as waste treatment system. Not only is waste reduced, but also is biogas produced. Biogas is used to substitute the use of any form of fuels such as fuel wood, charcoal, liquefied petroleum gas (LPG) for cooking and to generate electricity. Using biogas does not increase

Bundit Limmeechokchai

403

Advantages of the integrated pig-biogas-vegetable greenhouse system in North China  

Microsoft Academic Search

An integrated pig-biogas-vegetable greenhouse system (PBVGS) was designed and studied in Laiwu, Shandong Province of North China from 2001 to 2002, where 20 groups of PBVGS and their corresponding controls were investigated. The PBVGS involves building a pigsty and a biogas digester in a vegetable greenhouse, putting pig dung into the biogas digester for fermentation, using the biogas for increasing

Xinshan Qi; Shuping Zhang; Yuzhi Wang; Renqing Wang

2005-01-01

404

Biomethanation of poultry litter leachate in UASB reactor coupled with ammonia stripper for enhancement of overall performance.  

PubMed

In the present study possibility of coupling stripper to remove ammonia to the UASB reactor treating poultry litter leachate was studied to enhance the overall performance of the reactor. UASB reactor with stripper as ammonia inhibition control mechanism exhibited better performance in terms of COD reduction (96%), methane yield (0.26m(3)CH(4)/kg COD reduced), organic loading rate (OLR) (18.5kg COD m(-3)day(-1)) and Hydraulic residence time (HRT) (12h) compared to the UASB reactor without stripper (COD reduction: 92%; methane yield: 0.21m(3)CH(4)/kg COD reduced; OLR: 13.6kg CODm(-3)day(-1); HRT: 16h). The improved performance was due to the reduction of total ammonia nitrogen (TAN) and free ammonia nitrogen (FAN) in the range of 75-95% and 80-95%, respectively by the use of stripper. G/L (air flow rate/poultry leachate flow rate) in the range of 60-70 and HRT in the range of 7-9min are found to be optimum parameters for the operation of the stripper. PMID:18524578

Gangagni Rao, A; Sasi Kanth Reddy, T; Surya Prakash, S; Vanajakshi, J; Joseph, Johny; Jetty, Annapurna; Rajashekhara Reddy, A; Sarma, P N

2008-06-03

405

Prediction of moving bed biofilm reactor (MBBR) performance for the treatment of aniline using artificial neural networks (ANN).  

PubMed

In this study, the results of 1-year efficiency forecasting using artificial neural networks (ANN) models of a moving bed biofilm reactor (MBBR) for a toxic and hard biodegradable aniline removal were investigated. The reactor was operated in an aerobic batch and continuous condition with 50% by volume which was filled with light expanded clay aggregate (LECA) as carrier. Efficiency evaluation of the reactors was obtained at different retention time (RT) of 8, 24, 48 and 72 h with an influent COD from 100 to 4000 mg/L. Exploratory data analysis was used to detect relationships between the data and dependent evaluated one. The appropriate architecture of the neural network models was determined using several steps of training and testing of the models. The ANN-based models were found to provide an efficient and a robust tool in predicting MBBR performance for treating aromatic amine compounds. PMID:20399558

Delnavaz, M; Ayati, B; Ganjidoust, H

2010-03-23

406

Microbiological and performance evaluation of sequencing batch reactor for textile wastewater treatment.  

PubMed

This study focused on laboratory-scaled and real-scaled treatment plant performances and microbiological investigations for the optimum treatment of textile industry wastewater performed with sequencing batch reactor (SBR). As a result of experimental studies of laboratory-scaled SBR treatment unit, optimum treatment efficiency was taken from 0.5 h filling to 1.5 h. reaction to 1.5 h. settlement to 0.5 h. discharge-idle periods. Average chemical oxygen demand (COD) removal efficiency of SBR of laboratory-scaled textile industry was 75%, whereas average turbidity and color removal (coloration number [RES, m(-1)] 586 nm) efficiencies were 90% and 75%, respectively. Optimum reaction and settlement periods were used in a real-scaled plant, and plant efficiency was examined for parameters such as COD, phenol, pH, mixed liquor suspended solids (MLSS) and sludge volume index (SVI). In this study, optimum reaction and settlement periods for treatment of textile industry wastewater were determined within a SBR in a laboratory-scaled plant. These reaction and settlement periods were verified with the measurement of COD, color, and turbidity parameters. Floc structure and protozoa-metazoa species of activated sludge in a SBR were also determined. Optimum reaction and settlement times were used in a real-scaled plant, and plant efficiency was examined for COD, Phenol, pH, MLSS, and SVI parameters. The corresponding values were found as appropriate, acceptable, and meaningful because of variance value of statistical analysis. Protozoa and metazoan in the activated sludge in the laboratory-scaled plant were investigated. Peranema sp., Epistylis sp., Didinium sp., Chilodonella sp., Opercularia sp., Vorticella sp. as protozoa species and Habrotrocha sp., Philodina sp. as metazoa species were determined. PMID:22834223

Ogleni, Nurtac; Arifoglu, Yasemin Damar; Ileri, Recep

2012-04-01

407

Central Electricity Generating Board's nuclear power stations: a review of the first 10 years of Magnox reactor plant performance and reliability  

Microsoft Academic Search

Statistics of the performance of the Magnox reactor plants are presented. ; Station availability data in terms of cumulative lifetime load factors and winter ; period performance are given and the contributions of major plant items to ; availability described briefly. Data on reactor availabilities are givenm losses ; of availability have been allocated between planned outages, forced outages for

F. Dixon; H. K. Simons

1974-01-01

408

Impact of design options on natural circulation performance of the AFR-300 advanced fast reactor.  

SciTech Connect

The AFR-300, Advanced Fast Reactor (300 Mwe), has been proposed as a Generation IV concept. It could also be used to dispose of surplus weapons grade plutonium or as an actinide burner for transmutation of high level radioactive waste. AFR-300 uses metallic fuel and sodium coolant. The design of AFR-300 takes account of the successful design and operation of EBR-II, but the AFR-300 design includes a number of advances such as an advanced fuel cycle, inspectability and improved economics. One significant difference between AFR-300 and EBR-II is that AFR-300 is considerably larger. Another significant difference is that AFR-300 has no auxiliary EM pump in the primary loop to guarantee positive core flow when the main primary pumps are shut down. Thus, one question that has come up in connection with the AFR-300 design is whether natural circulation flow is sufficient to prevent damage to the core if the primary pumps fail. Insufficient natural circulation flow through the core could result in high cladding temperatures and cladding failure due to eutectic penetration of the cladding by the metal fuel. The rate of eutectic penetration of the cladding is strongly temperature dependent, so cladding failure depends on how hot the cladding gets and how long it is at elevated temperatures. To investigate the adequacy of natural circulation flow, a number of pump failure transients and a number of design options have been analyzed with the SASSYS-1 systems analysis code. This code has been validated for natural circulation behavior by analysis of Shutdown Heat Removal Tests performed in EBR-II. The AFR-300 design includes flywheels on the primary pumps to extend the pump coastdown times, and the size of the flywheels can be picked to give optimum coastdown times. One series of transients that has been run consists of protected loss-of-flow transients with various values for the combined moment of inertia of the pump, the motor and the flywheel giving coastdown times from 70 seconds to 586 seconds. In this transient series both the main pump motors and the pony motors lose power. Another series of loss-of-flow cases involved staggered failures of the pony motors. The main pump motors fail, the reactor scrams, and the pumps coast down to pony motor speed. Then at various times the pony motors are assumed to fail. If the pony motors fail at the wrong time, then the resulting transient can be more severe than if the pony motors failed at the same time as the main motors. A third series of cases involved a reactor scram followed by failure of both the main pump motors and the pony motors at various times. For all of these cases, satisfactory natural circulation behavior can be obtained if the right design options are used.

Dunn, F. D.

2002-03-07

409

The proven performance of liquid metal breeder reactors using mixed oxide fuel  

SciTech Connect

Since the first liquid-metal-cooled reactors were constructed in the 1950's, a variety of fuel types has been utilized both in the United States and abroad. Nearly forty years of experience have provided ample evidence of the high level of success achieved by the use of mixed oxide (UO/PuO) in liquid metal fast breeder reactors. This paper will outline the fuel experience of the Fast Flux Test Facility, the largest liquid metal fast breeder research reactor in the world. 10 refs., 1 fig.

Munn, W.I.

1990-06-01

410

Benefits of supplementing an industrial waste anaerobic digester with energy crops for increased biogas production  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer This study demonstrates the feasibility of co-digestion food industrial waste with energy crops. Black-Right-Pointing-Pointer Laboratory batch co-digestion led to improved methane yield and carbon to nitrogen ratio as compared to mono-digestion of industrial waste. Black-Right-Pointing-Pointer Co-digestion was also seen as a means of degrading energy crops with nutrients addition as crops are poor in nutrients. Black-Right-Pointing-Pointer Batch co-digestion methane yields were used to predict co-digestion methane yield in full scale operation. Black-Right-Pointing-Pointer It was concluded that co-digestion led an over all economically viable process and ensured a constant supply of feedstock. - Abstract: Currently, there is increasing competition for waste as feedstock for the growing number of biogas plants. This has led to fluctuation in feedstock supply and biogas plants being operated below maximum capacity. The feasibility of supplementing a protein/lipid-rich industrial waste (pig manure, slaughterhouse waste, food processing and poultry waste) mesophilic anaerobic digester with carbohydrate-rich energy crops (hemp, maize and triticale) was therefore studied in laboratory scale batch and continuous stirred tank reactors (CSTR) with a view to scale-up to a commercial biogas process. Co-digesting industrial waste and crops led to significant improvement in methane yield per ton of feedstock and carbon-to-nitrogen ratio as compared to digestion of the industrial waste alone. Biogas production from crops in combination with industrial waste also avoids the need for micronutrients normally required in crop digestion. The batch co-digestion methane yields were used to predict co-digestion methane yield in full scale operation. This was done based on the ratio of methane yields observed for laboratory batch and CSTR experiments compared to full scale CSTR digestion of industrial waste. The economy of crop-based biogas production is limited under Swedish conditions; therefore, adding crops to existing industrial waste digestion could be a viable alternative to ensure a constant/reliable supply of feedstock to the anaerobic digester.

Nges, Ivo Achu, E-mail: Nges.Ivo_Achu@biotek.lu.se [Department of Biotechnology, Lund University, P.O. Box 124, SE 221 00 Lund (Sweden); Escobar, Federico; Fu Xinmei; Bjoernsson, Lovisa [Department of Biotechnology, Lund University, P.O. Box 124, SE 221 00 Lund (Sweden)

2012-01-15

411

Comparison of operating characteristics of a 34-kW diesel engine fueled with low-energy gas, biogas, and diesel fuel  

SciTech Connect

Diesel engines can be operated in a dual-fuel mode with low-energy gas, also called LEG, from thermal gasification or with biogas from anaerobic digestion. This article compares the operating characteristics of a 34-kW diesel engine operating in dual-fuel modes with the operating characteristics of the same engine fueled with diesel oil. Performance curves comparing torque, speed, power, air ratio, effective efficiency, and exhaust temperature are presented for each mode of operation. In the low-energy gas, dual-fuel mode, the engine was supplied with low-energy gas from a batch-fed, downdraft gasifier fueled with densified solid waste. The filtered and cooled low-energy gas was fed to the diesel engine through a mixing chamber. In the biogas dual-fuel mode, the engine was supplied with synthetic biogas obtained by mixing natural gas with compressed carbon dioxide. The synthetic biogas was fed to the engine by a carburetor. Pilot diesel fuel was injected into the engine for ignition of both the low-energy gas and biogas. In both dual-fuel modes, 15 to 24% of the input fuel was diesel oil. It was found that the practical power output in the dual-fuel modes was 30 kW (86%) with biogas, and 25 kW (71%) with low-energy gas, as compared to 34 kW (100%) with normal diesel operation.

Ortiz-Canavate, J. (Ciudad Universitaria, Madrid, Spain); Vigil, S.A.; Goss, J.R.; Tchobanoglous, G.

1981-01-01

412

THERMAL PERFORMANCE OF A FAST NEUTRON TEST CONCEPT FOR THE ADVANCED TEST REACTOR  

SciTech Connect

Since 1967, the Advanced Test Reactor (ATR) located at Idaho National Laboratory (INL) has provided state-of-the-art experimental irradiation testing capability. A unique design is investigated herein for the purpose of providing a fast neutron flux test capability in the ATR. This new test capability could be brought on line in approximately 5 or 6 years, much sooner than a new test reactor could be built, to provide an interim fast-flux test capability in the timeframe before a fast-flux research reactor could be built. The proposed cost for this system is approximately $63M, much less than the cost of a new fast-flux test reactor. A concept has been developed to filter out a large portion of the thermal flux component by using a thermally conductive neutron absorber block. The objective of this study is to determine the feasibility of this experiment cooling concept.

Donna Post Guillen

2008-06-01

413

Operational performance of the three bean salad control algorithm on the ACRR (Annular Core Research Reactor)  

SciTech Connect

Experimental tests on the Annular Core Research Reactor have confirmed that the Three-Bean-Salad'' control algorithm based on the Pontryagin maximum principle can change the power of a nuclear reactor many decades with a very fast startup rate and minimal overshoot. The paper describes the results of simulations and operations up to 25 MW and 87 decades per minute. 3 refs., 4 figs., 1 tab.

Ball, R.M.; Madaras, J.J. (B and W Nuclear Technologies, Lynchburg, VA (USA). Space and Defense Systems); Trowbridge, F.R. Jr.; Talley, D.G.; Parma, E.J. Jr. (Sandia National Labs., Albuquerque, NM (USA))

1991-01-01

414

Simplified boiling water reactor thermal-hydraulic performance: A RELAP5\\/MOD2 model simulation  

Microsoft Academic Search

The results of a simulation activity on a General Electric (GE) simplified boiling water reactor (SBWR) carried out at ENEL (the Italian Electricity Board) are discussed. The SBWR is a medium-size [600 MW (electric)] new generation reactor developed by GE, whose safety is ensured by means of passive systems (water gravity injection, pressure suppression, and passive heat removal). The RELAP5\\/MOD2

P. Barbucci; L. Bella; F. Oriolo

1995-01-01

415

PERFORMANCE OF UNIAXIAL CREEP MACHINES IN THE NRX AND NRU REACTORS  

Microsoft Academic Search

Reactor Loops Branch began operating creep experiments in 1965. At that time, Mk-IV and Mk-VI machines were in use in NRX and NRU. Since then, a number of disposable machines have been built, resulting in the Mk-X design which may be used in either reactor. Control equipment has been automated, and data retrieval computerized. The original and re-designed equipment is

1971-01-01

416

Performance Comparison of Metallic, Actinide Burning Fuel in Lead-Bismuth and Sodium Cooled Fast Reactors  

Microsoft Academic Search

Various methods have been proposed to âincinerate❠or âtransmutate❠the current inventory of trans-uranic waste (TRU) that exits in spent light-water-reactor (LWR) fuel, and weapons plutonium. These methods include both critical (e.g., fast reactors) and non-critical (e.g., accelerator transmutation) systems. The work discussed here is part of a larger effort at the Idaho National Engineering and Environmental Laboratory (INEEL) and

Kevan Dean Weaver; James Stephen Herring; Philip Elsworth Mac Donald

2001-01-01

417

Performance of an on-site UASB reactor treating leachate at low temperature  

Microsoft Academic Search

A pilot-scale UASB reactor was used to study treatment of municipal landfill leachate (COD 1.5–3.2gl?1) at low temperatures (13–23°C) and in on-site conditions for 226days. The reactor was successfully operated by decreasing the process temperature as leachate temperature decreased in winter. Despite changes in leachate quality, 65–75% COD and up to 95% BOD7 removals were achieved at 18–23°C with organic

Riitta H. Kettunen; Jukka A. Rintala

1998-01-01

418

Simulation of short-current limiting performance of 3-phase reactor superconducting fault current limiter  

Microsoft Academic Search

The 3-phase reactor superconducting fault current limiter (SCFCL) consists of three superconducting windings with the same number of turns, which are wound on a single iron core. In a normal condition, it is a good conductor with no impedance because the flux is zero in the iron core. However, under a single-line-to-ground fault, it becomes a reactor with large inductance

Zhou Youqing; Zhang Xuhong; Zhu Qing; Wu Guiqing

2002-01-01

419

Performances and microbial features of an aerobic packed-bed biofilm reactor developed to post-treat an olive mill effluent from an anaerobic GAC reactor  

PubMed Central

Background Olive mill wastewater (OMW) is the aqueous effluent of olive oil producing processes. Given its high COD and content of phenols, it has to be decontaminated before being discharged. Anaerobic digestion is one of the most promising treatment process for such an effluent, as it combines high decontamination efficiency with methane production. The large scale anaerobic digestion of OMWs is normally conducted in dispersed-growth reactors, where however are generally achieved unsatisfactory COD removal and methane production yields. The possibility of intensifying the performance of the process using a packed bed biofilm reactor, as anaerobic treatment alternative, was demonstrated. Even in this case, however, a post-treatment step is required to further reduce the COD. In this work, a biological post-treatment, consisting of an aerobic biological "Manville" silica bead-packed bed aerobic reactor, was developed, tested for its ability to complete COD removal from the anaerobic digestion effluents, and characterized biologically through molecular tools. Results The aerobic post-treatment was assessed through a 2 month-continuous feeding with the digested effluent at 50.42 and 2.04 gl-1day-1 of COD and phenol loading rates, respectively. It was found to be a stable process, able to remove 24 and 39% of such organic loads, respectively, and to account for 1/4 of the overall decontamination efficiency displayed by the anaerobic-aerobic integrated system when fed with an amended OMW at 31.74 and 1.70 gl-1day-1 of COD and phenol loading rates, respectively. Analysis of 16S rRNA gene sequences of biomass samples from the aerobic reactor biofilm revealed that it was colonized by Rhodobacterales, Bacteroidales, Pseudomonadales, Enterobacteriales, Rhodocyclales and genera incertae sedis TM7. Some taxons occurring in the influent were not detected in the biofilm, whereas others, such as Paracoccus, Pseudomonas, Acinetobacter and Enterobacter, enriched significantly in the biofilter throughout the treatment. Conclusion The silica-bead packed bed biofilm reactor developed and characterized in this study was able to significantly decontaminate anaerobically digested OMWs. Therefore, the application of an integrated anaerobic-aerobic process resulted in an improved system for valorization and decontamination of OMWs.

Bertin, Lorenzo; Colao, Maria Chiara; Ruzzi, Maurizio; Marchetti, Leonardo; Fava, Fabio

2006-01-01

420

Microwave and thermal pretreatment as methods for increasing the biogas potential of secondary sludge from municipal wastewater treatment plants.  

PubMed

In the present study, the sludge was pretreated with microwave irradiation and low-temperature thermal method, both conducted under the same temperature range (30-100°C). Microwave pretreatment was found to be superior over the thermal treatment with respect to sludge solubilization and biogas production. Taking into account the specific energy demand of solubilization, the sludge pre-treated at 60-70°C by microwaves of 900 W was chosen for further experiments in continuous mode, which was more energetically sustainable compared to lower value (700 W) and thermal treatment. Continuous biogas reactor experiments indicated that pre-treated sludge (microwave irradiation: 900 W, temperature: 60-70°C) gave 35% more methane, compared to untreated sludge. Moreover, the results of this study clearly demonstrated that microwave pretreated sludge showed better degree of sanitation. PMID:23500587

Kuglarz, Mariusz; Karakashev, Dimitar; Angelidaki, Irini

2013-02-09

421

Wet air oxidation as a pretreatment option for selective biodegradability enhancement and biogas generation potential from complex effluent.  

PubMed

This study looks at the possibility of wet air oxidation (WAO) based pretreatment of complex effluent to selectively enhance the biodegradability (without substantial COD destruction) and facilitate biogas generation potential. A lab-scale wet air oxidation reactor with biomethanated distillery wastewater (B-DWW) as a model complex effluent (COD 40,000 mg L(-1)) was used to demonstrate the proof-of-concept. The studies were conducted using a designed set of experiments and reaction temperature (150-200°C), air pressure (6-12 bar) and reaction time (15-120 min) were the main process variables of concern for WAO process optimization. WAO pretreatment of B-DWW enhanced the biodegradability of the complex wastewater by the virtue of enhancing its biodegradability index (BI) from 0.2 to 0.88, which indicate favorable Biochemical Methane Potential (BMP) for biogas generation. The kinetics of COD destruction and BI enhancement has also been reported. PMID:22789827

Padoley, K V; Tembhekar, P D; Saratchandra, T; Pandit, A B; Pandey, R A; Mudliar, S N

2012-06-23

422

Hydraulic performance of a proposed in situ photocatalytic reactor for degradation of MTBE in water.  

PubMed

Methyl tert-butyl ether (MTBE) groundwater remediation projects often require a combination of technologies resulting in increasing the project costs. A cost-effective in situ photocatalytic reactor design, Honeycomb II, is proposed and tested for its efficiency in MTBE degradation at various flows. This study is an intermediate phase of the research in developing an in situ photocatalytic reactor for groundwater remediation. It examines the effect of the operating variables: air and water flow and double passages through Honeycomb II, on the MTBE removal. MTBE vaporisation is affected by not only temperature, Henry's law constant and air flow to volume ratio but also reactor geometry. The column reactor achieved more than 84% MTBE removal after 8 h at flows equivalent to horizontal groundwater velocities slower than 21.2 cm d?¹. Despite the contrasting properties between a photocatalytic indicator methylene blue and MTBE, the reactor efficiency in degrading both compounds showed similar responses towards flow (equivalent groundwater velocity and hydraulic residence time (HRT)). The critical HRT for both compounds was approximately 1 d, which corresponded to a velocity of 21.2 cm d?¹. A double pass through both new and used catalysts achieved more than 95% MTBE removal after two passes in 48 h. It also verified that the removal efficiency can be estimated via the sequential order of the removal efficiency of one pass obtained in the laboratory. This study reinforces the potential of this reactor design for in situ groundwater remediation. PMID:21067793

Lim, Leonard Lik Pueh; Lynch, Rod

2010-11-09

423

Optimisation of biogas production from anaerobic digestion of agro-industrial waste streams in Brazil.  

PubMed

The important Brazilian agro-industry produces significant amounts of wastewater with high concentrations of biodegradable compounds. A lot can be gained if wastewater treatment would take place using anaerobic reactors instead of the anaerobic lagoons generally used now. Apart from preventing methane emissions to the atmosphere this would permit the use of the biogas as a source of energy. To facilitate implementation of this technology also in small and intermediate sized companies a system requiring only minimal maintenance is needed. The need for maintenance by skilled labour can be reduced using an automated process control system, which is being developed. Cassava (manioc, tapioca) processing wastewater has been treated in a lab scale UASB reactor equipped with an on-line monitoring system, to test a control strategy based mainly on pH control. Good results have been obtained treating not only pre-acidified but also treating raw (diluted) cassava processing wastewater. PMID:19001722

Boncz, M A; Bezerra, L Pinheiro; Ide, C Nobuyoshi; Paulo, P Loureiro

2008-01-01

424

Investigating the performance of a novel cyclic rotating-bed biological reactor compared with a sequencing continuous-inflow reactor for biodegradation of catechol in wastewater.  

PubMed

The main objective of this study was to investigate the performance of a cyclic rotating-bed biological reactor (CRBR) in comparison to a sequencing continuous-inflow reactor (SCR) for the biodegradation and mineralization of catechol. Results showed that catechol degradation and mineralization in the SCR at the organic loading of 7.82kgCOD/m(3)d and the hydraulic retention time (HRT) of 9h were 28.2% and 10.3%, respectively. Under similar operating conditions to SCR, steady-state performance of CRBR with polyurethane foam (PUF) media for degradation and mineralization of catechol achieved was 98.7% and 97.9%, respectively. In comparison, the CRBR with 2H media attained average steady-state catechol degradation and mineralization of 89.1% and 83.6%, respectively, under similar conditions. Accordingly, the CRBR with PUF media presents a promising process for efficiently treating wastewater containing high concentrations of toxic, inhibitory and resistant compounds at a relatively short HRT. PMID:23623431

Aghapour, Ali Ahmad; Moussavi, Gholamreza; Yaghmaeian, Kamyar

2013-03-28

425

Performance of intermittently aerated up-flow sludge bed reactor and sequencing batch reactor treating industrial estate wastewater: a comparative study.  

PubMed

In this study, an innovative aerobic/anoxic sludge bed bioreactor with two feeding regimes, continuous-fed (an up-flow sludge bed reactor (USBR)) and batch fed (sequencing batch reactor (SBR)), was evaluated for the treatment of an industrial estate wastewater with low BOD(5)/COD ratio. The process performance in the two regimes was compared. Two numerical independent variables (retention/react time and aeration time) were selected to analyze, model and optimize the process. Response surface methodology with central composite design (CCD) was used with five levels of hydraulic retention time (HRT)/react time (12-36h) and aeration time (40-60min/h). In order to analyze the process, ten dependent parameters as the process responses were studied. As a result, HRT/react time showed a decreasing impact on the responses measured in both hydraulic regimes, USBR and SBR. The USBR showed better performance than the SBR in removal of total COD, slowly biodegradable COD, total nitrogen and total Kjeldahl nitrogen. PMID:22940360

Asadi, A; Zinatizadeh, A A L; Hasnain Isa, M

2012-07-16

426

Comparison of different procedures to stabilize biogas formation after process failure in a thermophilic waste digestion system: Influence of aggregate formation on process stability  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Mechanism of process recovery with calcium oxide. Black-Right-Pointing-Pointer Formation of insoluble calcium salts with long chain fatty acids and phosphate. Black-Right-Pointing-Pointer Adsorption of VFAs by the precipitates resulting in the formation of aggregates. Black-Right-Pointing-Pointer Acid uptake and phosphate release by the phosphate-accumulating organisms. Black-Right-Pointing-Pointer Microbial degradation of volatile fatty acids in the aggregates. - Abstract: Following a process failure in a full-scale biogas reactor, different counter measures were undertaken to stabilize the process of biogas formation, including the reduction of the organic loading rate, the addition of sodium hydroxide (NaOH), and the introduction of calcium oxide (CaO). Corresponding to the results of the process recovery in the full-scale digester, laboratory experiments showed that CaO was more capable of stabilizing the process than NaOH. While both additives were able to raise the pH to a neutral milieu (pH > 7.0), the formation of aggregates was observed particularly when CaO was used as the additive. Scanning electron microscopy investigations revealed calcium phosphate compounds in the core of the aggregates. Phosphate seemed to be released by phosphorus-accumulating organisms, when volatile fatty acids accumulated. The calcium, which was charged by the CaO addition, formed insoluble salts with long chain fatty acids, and caused the precipitation of calcium phosphate compounds. These aggregates were surrounded by a white layer of carbon rich organic matter, probably consisting of volatile fatty acids. Thus, during the process recovery with CaO, the decrease in the amount of accumulated acids in the liquid phase was likely enabled by (1) the formation of insoluble calcium salts with long chain fatty acids, (2) the adsorption of volatile fatty acids by the precipitates, (3) the acid uptake by phosphorus-accumulating organisms and (4) the degradation of volatile fatty acids in the aggregates. Furthermore, this mechanism enabled a stable process performance after re-activation of biogas production. In contrast, during the counter measure with NaOH aggregate formation was only minor resulting in a rapid process failure subsequent the increase of the organic loading rate.

Kleyboecker, A.; Liebrich, M.; Kasina, M. [Microbial GeoEngineering, Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, 14473 Potsdam (Germany); Kraume, M. [Chemical and Process Engineering, Technical University Berlin, 10623 Berlin (Germany); Wittmaier, M. [Institute for Recycling and Environmental Protection, Bremen University of Applied Sciences, 28199 Bremen (Germany); Wuerdemann, H., E-mail: wuerdemann@gfz-potsdam.de [Microbial GeoEngineering, Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, 14473 Potsdam (Germany)

2012-06-15

427

Analysis of problems with dry fermentation process for biogas production  

NASA Astrophysics Data System (ADS)

The technology of dry anaerobic fermentation is still meeting with some scepticism, and therefore in most biogas plants are used wet fermentation technology. Fermentation process would be not complete without an optimal controlled condition: dry matter content, density, pH, and in particular the reaction temperature. If is distrust of dry fermentation eligible it was on the workplace of the Department of Power Engineering at University of Zilina built an experimental small-scale biogas station that allows analysis of optimal parameters of the dry anaerobic fermentation, in particular, however, affect the reaction temperature on yield and quality of biogas.

Pilát, Peter; Patsch, Marek; Janda?ka, Jozef

2012-04-01

428

Neutronic performance of the WWR-M research reactor in Ukraine.  

SciTech Connect

The 10 MW, WWR-M research reactor of the Kiev Institute for Nuclear Research is jointly studied with the Argonne National Laboratory to examine the feasibility of conversion from HEU (36%) to LEU (19.75%) fuel. A potential core configuration was chosen for comparison of analytical results with HEU fuel and candidate replacement LEU fuels. Core reactivity, fuel assembly power, experiment flux, fuel-cycle length, the number of fuel assemblies consumed per year, and shutdown margins are compared using HEU and LEU fuels. The reactor currently uses HEU (36%) WWR-M2 fuel assemblies (3 tubes, UO2-Al fuel meat with 1.1 gU/cm3 and 37.0 g {sup 235}U). Candidate LEU replacement fuel assemblies, which would result in the same fuel cycle length and the same annual fuel consumption as the HEU (36%) fuel are: LEU WWR-M2 (3 tubes, UO2-Al fuel meat with 2.3 gU/cm3 and 38.3 g 235U) and LEU WWR-MR (37 pins, U9Mo-Al fuel meat with 2.4 gU/cm3 and 38.1 g {sup 235}U). Five LEU WWR-M2 fuel assemblies with 41.7 g {sup 235}U per assembly, UO{sub 2}-Al fuel meat with 2.5 gU/cm3, and a fueled height of 50 cm have completed irradiation testing in the WWR-M reactor at the Petersburg Nuclear Physics Institute in Gatchina to an average 235U burnup of over 70%. This LEU fuel is considered to be qualified for conversion of the WWR-M reactor in Kiev and other research reactors using HEU (36%) WWR-M2 fuel assemblies. For reactors using assemblies with a fueled height of 60 cm, the 235U content per assembly would be 50 g with the same fuel meat composition as the fuel assemblies that were tested in Gatchina. Two 37-pin LEU test assemblies - one with UO{sub 2}-Al fuel meat and about 48 g {sup 235}U and the other with U9Mo-Al fuel meat and about 96 g {sup 235}U are scheduled to begin irradiation testing in the WWR-M reactor in Gatchina before the end of 2002. If these tests (lasting about two years) are successful, LEU pin-type fuel assemblies with up to 96 g 235U would be candidate fuels for LEU conversion of the WWR-M reactor in Kiev and other research reactors using WWR-M2 fuel assemblies.

Pond, R. B.; Hanan, N. A.; Matos, J. E.; Mahlers, Y.; Dyakov, A.; Technology Development; Kiev Inst. for Nuclear Research

2002-01-01

429

Stability of test environments for performance evaluation of materials for the modular high-temperature gas-cooled reactor  

Microsoft Academic Search

Stability of the primary helium-based coolant test gas for use in performance ests of materials for the Modular High-Temperature Gas-Cooled Reactor (MHTGR) was determined. Results of tests of the initial gas chemistry from General Atomics (GA) at elevated temperatures, and the associated results predicted by the SOLGASMIX[trademark] modelling package are presented. Results indicated that for this gas composition and at

G. L. Edgemon; D. F. Wilson; G. E. C. Bell

1993-01-01

430

Stability of test environments for performance evaluation of materials for the modular high-temperature gas-cooled reactor  

Microsoft Academic Search

Stability of the primary helium-based coolant test gas for use in performance ests of materials for the Modular High-Temperature Gas-Cooled Reactor (MHTGR) was determined. Results of tests of the initial gas chemistry from General Atomics (GA) at elevated temperatures, and the associated results predicted by the SOLGASMIX{trademark} modelling package are presented. Results indicated that for this gas composition and at

G. L. Edgemon; D. F. Wilson; G. E. C. Bell

1993-01-01

431

Performance of uasb reactor treating leachate from acidogenic fermenter in the two-phase anaerobic digestion of food waste  

Microsoft Academic Search

This study was conducted to investigate the performance of the upflow anaerobic sludge blanket (UASB) reactor treating leachate from acidogenic fermenter in the two-phase anaerobic digestion of food waste. The chemical oxygen demand (COD) removal efficiency was consistently over 96% up to the loading rates of 15.8gCOD\\/ld. The methane production rate increased to 5.5l\\/ld. Of all the COD removed, 92%

H. S Shin; S. K Han; Y. C Song; C. Y Lee

2001-01-01

432

Performance and productivity improvements in an advanced dielectric etch reactor for sub 0.3 ?m applications  

Microsoft Academic Search

Dielectric film etching represents one of the most challenging aspects of semiconductor processing. At present, a dielectric etch reactor must be capable of handling a range of dielectrics, such as doped and undoped silica glass, silicon nitride, organic anti-reflection layers and low-k dielectric materials of a predominantly organic composition. Successful etch tools perform the “critical” steps required for contact, self-aligned

M. Srinivasan; R. Caple; G. Hills; G. Mueller; T. Nguyen; E. Wagganer

1998-01-01

433

Analysis of MOX fuel behavior in reduced-moderation water reactor by fuel performance code FEMAXI-RM  

Microsoft Academic Search

To assess the feasibility of the 31% Pu-MOX fuel rod design of reduced-moderation water reactor (RMWR) in terms of thermal and mechanical behaviors, a single rod assumed to be irradiated in the core of RMWR up to 106GWd\\/tHM has been analyzed by a fuel performance code FEMAXI-RM which is an extended version of FEMAXI-6 code. In the analysis, design specifications

Motoe Suzuki; Hiroaki Saitou; Takamichi Iwamura

2004-01-01

434

Thermal modelling of the completely stirred anaerobic reactor treating pig manure at low range of mesophilic conditions.  

PubMed

Most of Chinese middle size agricultural biogas plants run at the lower range of mesophilic conditions and low organic loading rates (OLRs) which result in the low biogas production. How to obtain an economically viable operation mode is a challenge for Chinese farm biogas plants. In this study, the performance of completely stirred anaerobic reactors treating pig manure was studied at 20, 28 and 38 °C. A thermal mathematic model was accordingly developed to decide the optimum digesting temperature and OLRs considering ambient temperature of 20, 10 and 0 °C. The regression surface model can fit well on the experimental data when the ambient temperature was around 10-20 °C, at which maximum net energy production (Np,max) can be achieved when the digesters run at OLR of 4.6-5.4 kgODM/m(3) d with temperature of above 26 °C. Co-digestion on the pig farm was suggested in winter in order to increase the Np. PMID:23669604

Guo, Jianbin; Dong, Renjie; Clemens, Joachim; Wang, Wei

2013-05-10

435

Performance Comparison of Metallic, Actinide Burning Fuel in Lead-Bismuth and Sodium Cooled Fast Reactors  

SciTech Connect

Various methods have been proposed to “incinerate” or “transmutate” the current inventory of trans-uranic waste (TRU) that exits in spent light-water-reactor (LWR) fuel, and weapons plutonium. These methods include both critical (e.g., fast reactors) and non-critical (e.g., accelerator transmutation) systems. The work discussed here is part of a larger effort at the Idaho National Engineering and Environmental Laboratory (INEEL) and at the Massachusetts Institute of Technology (MIT) to investigate the suitability of lead and lead-alloy cooled fast reactors for producing low-cost electricity as well as for actinide burning. The neutronics of non-fertile fuel loaded with 20 or 30-wt% light water reactor (LWR) plutonium plus minor actinides for use in a lead-bismuth cooled fast reactor are discussed in this paper, with an emphasis on the fuel cycle life and isotopic content. Calculations show that the average actinide burn rate is similar for both the sodium and lead-bismuth cooled cases ranging from -1.02 to -1.16 g/MWd, compared to a typical LWR actinide generation rate of 0.303 g/MWd. However, when using the same parameters, the sodium-cooled case went subcritical after 0.2 to 0.8 effective full power years, and the lead-bismuth cooled case ranged from 1.5 to 4.5 effective full power years.

Weaver, Kevan Dean; Herring, James Stephen; Mac Donald, Philip Elsworth

2001-04-01

436

Analysis of the Performance of a Flow Reactor for Use with Microcolumn HPLC  

PubMed Central

Postcolumn derivatization reactions can be used to improve detector sensitivity or selectivity. The advantages of capillary chromatography for trace analysis could be augmented if there were postcolumn reactors suitable for microchromatographic systems. However, postcolumn derivatization is a challenge because of the small peak volumes associated with capillary columns. We have developed a postcolumn flow reactor from microchannels formed in fluorinated ethylene propylene and 50-?m fused-silica tubing for use with capillary HPLC analyses. Theoretical and experimental evidence show that the reactor, which operates in the Taylor dispersion regime, enables contact of analyte and derivatization streams purely by diffusion. Reactor lengths as short as 2 cm allow formation of copper(II)–peptide complexes that are detected electrochemically at a carbon fiber microelectrode. The reactor has been used with 100-?m-i.d. columns with insignificant effects (i.e., <3%) on peak band spreading. Theoretical calculations indicate that even smaller i.d. columns can be used with little effect on chromatographic resolution.

Beisler, Amy T.; Sahlin, Eskil; Schaefer, Kathleen E.; Weber, Stephen G.

2006-01-01

437

Novel reactor design configuration for contamination control and improved performance in the polysilicon doping process using POCl3  

NASA Astrophysics Data System (ADS)

Conventional POCl3 reactors have process limitations because of the hazardous nature of process by-products. Experiments were conducted using a novel design quartz flange and stainless steel clamp exhaust configuration, along with a scavenger insulation block, which eliminated process by-product buildup inside the reactor tube in the scavenger area. Experiments included variations in doping temperature, process time, POCl3 flow rate, and carrier and exhaust gas flow rates. This novel(sup e) hardware design practically eliminates by-product condensation and dripping outside the reactor, which reduces cross-contamination and stainless steel corrosion problems and prevents potential minority carrier lifetime degradation. Equipment downtime is significantly reduced by eliminating autodoping and the need for frequent process tube steam cleans. Run capability is extended because of the new design, which also provides superior exhaust control and safer operation. The design also allows doubling of the number of wafers processed with improved sheet resistance uniformity. Regression equations were obtained for calculating sheet resistance, which can be a viable tool for process engineers. The new reactor configuration provides significant advantages in reduced equipment downtime, increased savings in material, and improved process performance.

Roy, Sudipto R.; Glynn, Phil; Hogan, Rod; Reynolds, Jeff

1994-08-01

438

The review of domestic and international biogas frontiers and technical achievements — A study of the development of biogas technology in Gansu Province  

Microsoft Academic Search

Biogas digester technology is an available method in mitigating energy crisis, dealing with global climate change and improving rural ecological environment. This paper study the development history, new trend and research hotpots of biogas technology of those countries in which biogas technology are well developed, contract different development models of these countries to reveal their qualities and law of development,

Wenguang Ding; Lijun Wang; Jinsong Chen; Yunrang Xian; Baoyu Chen

2011-01-01

439

Effects of organic loading rate and effluent recirculation on the performance of two-stage anaerobic digestion of vegetable waste.  

PubMed

The effects of organic loading rates (OLR) and effluent recirculation on dynamics of acidogenic and methanogenic processes in two-stage anaerobic digestion of vegetable waste were investigated. Two systems were performed at OLRs of 1.3, 1.7, 2.1 and 2.6gVS/L/d. One system recirculated the effluent from the methanogenic reactor to acidogenic reactor. With increasing OLRs, total volatile fatty acid (VFA) concentration increased to approximately 8500mg/L in acidogenic digester, where pH decreased from 6.4 to 5.2. Daily biogas production and methane content in methanogenic reactor increased from 1.2 to 4.4L/d and from 27.4% to 60.5%, respectively. However, inhibition of hydrolysis in acidogenic reactor was demonstrated under the OLR of 2.6gVS/L/d without recirculation, thus indicating system overloading. Effluent recirculation shown a considerable positive effect on alleviating VFA inhibition and improving biogas production in acidogenic reactor because of the effect of dilution and pH adjustment, particularly at high OLRs. PMID:23973975

Zuo, Zhuang; Wu, Shubiao; Zhang, Wanqin; Dong, Renjie

2013-08-02

440

Performance of commercial off-the-shelf microelectromechanical systems sensors in a pulsed reactor environment  

SciTech Connect

Prompted by the unexpected failure of piezoresistive sensors in both an elevated gamma-ray environment and reactor core pulse tests, we initiated radiation testing of several MEMS piezoresistive accelerometers and pressure transducers to ascertain their radiation hardness. Some commercial off-the-shelf sensors are found to be viable options for use in a high-energy pulsed reactor, but others suffer severe degradation and even catastrophic failure. Although researchers are promoting the use of MEMS devices in radiation-harsh environment, we nevertheless find assurance testing necessary.

Hobert, Keith Wdwin [Los Alamos National Laboratory; Heger, Arlen S [Los Alamos National Laboratory; Mc Cready, Steven S [Los Alamos National Laboratory

2010-01-01

441

Modelling of biogas extraction at an Italian landfill accepting mechanically and biologically treated municipal solid waste.  

PubMed

This paper presents the results of the modelling of the biogas extraction in a full-scale Italian landfill by the USEPA LandGEM model and the Andreottola-Cossu approach. The landfill chosen for this research ('Il Fossetto' plant, Monsummano Terme, Italy) had accepted mixed municipal raw waste for about 15?years. In the year 2003 a mechanical biological treatment (MBT) was implemented and starting from the end of the year 2006, the recirculation in the landfill of the concentrated leachate coming from the internal membrane leachate treatment plant was put into practice. The USEPA LandGEM model and the Andreottola-Cossu approach were chosen since they require only input data routinely acquired during landfill management (waste amount and composition) and allow a simplified calibration, therefore they are potentially useful for practical purposes such as landfill gas management. The results given by the models are compared with measured data and analysed in order to verify the impact of MBT on biogas production; moreover, the possible effects of the recirculation of the concentrated leachate are discussed. The results clearly show how both models can adequately fit measured data even after MBT implementation. Model performance was significantly reduced for the period after the beginning of recirculation of concentrated leachate when the probable inhibition of methane production, due to the competition between methanogens and sulfate-reducing bacteria, significantly influenced the biogas production and composition. PMID:21930528

Calabrò, Paolo S; Orsi, Sirio; Gentili, Emiliano; Carlo, Meoni

2011-09-18

442

Continuous biogas production from fodder beet silage as sole substrate  

Microsoft Academic Search

Abstract Since April 2000 a two-step anaerobic plant with two subsequent 500 m, methane\\/ton fresh fodder beet silage was obtained. Keywords Anaerobic digestion; biogas; biomass; energy plants; fodder beets; renewable energy; silage

P. A. Scherer; S. Dobler; S. Rohardt; R. Loock; B. Büttner; P. Nöldeke; A. Brettschuh

2003-01-01

443

The Small Biogas Plant: Its Construction, Operation and Use.  

National Technical Information Service (NTIS)

This booklet has been prepared in response to the demand for reference material to help interested parties design and operate small biogas plants. It is written in relatively simple language, understandable to people with limited scientific and technical ...

F. D. Maramba E. D. Obias C. C. Taganas

1977-01-01

444

Performance Analysis of Potassium Heat Pipes Radiator for HP-STMCs Space Reactor Power System  

NASA Astrophysics Data System (ADS)

A detailed design and performance results of C-C finned, and armored potassium heat pipes radiator for a 110 kWe Heat Pipes-Segmented Thermoelectric Module Converters (HP-STMCs) Space Reactor Power system (SRPS) are presented. The radiator consists of two sections; each serves an equal number of STMCs and has 162 longitudinal potassium heat pipes with 0.508 mm thick C-C fins. The width of the C-C fins at the minor diameter of the radiator is almost zero, but increases with distance along the radiator to reach 3.7 cm at the radiator's major diameter. The radiator's heat pipes (OD = 2.42 cm in front and 3.03 cm in rear) have thin titanium (0.0762 mm thick) liners and wicks (0.20 mm thick with an effective pore radius of 12-16 ?m) and a 1.016 mm thick C-C wall. The wick is separated from the titanium liner by a 0.4 mm annulus filled with liquid potassium to increase the capillary limit. The outer surfaces of the heat pipes in the front and rear sections of the radiator are protected with a C-C armor that is 2.17 mm and 1.70 mm thick, respectively. The inside surface of the heat pipes in the front radiator is thermally insulated while the C-C finned condensers of the rear heat pipes are exposed, radiating into space through the rear opening of the radiator cavity. The heat pipes in both the front and the rear radiators have a 1.5 m long evaporator section and each dissipates 4.47 kW while operating at 43.6% of the prevailing sonic limit. The front and rear radiator sections are 5.29 m and 2.61 m long with outer surface area and mass of 47.1 m2 and 314.3 kg, and 39.9 m2 and 243.2 kg, respectively. The total radiator is 7.63 m long and has minor and major diameters of 1.48 m and 5.57 m, respectively, and a total surface area of 87 m2; however, the effective radiator area, after accounting for heat rejection through the rear of the radiator cavity, is 98.8 m2. The radiator's total mass including the C-C armor is 557.5 kg and the specific area and specific mass are 6.41 kg/m2 and 5.07 kg/kWe, respectively.

El-Genk, Mohamed S.; Tournier, Jean-Michel

2004-02-01

445

Performance Analysis of Potassium Heat Pipes Radiator for HP-STMCs Space Reactor Power System  

SciTech Connect

A detailed design and performance results of C-C finned, and armored potassium heat pipes radiator for a 110 kWe Heat Pipes-Segmented Thermoelectric Module Converters (HP-STMCs) Space Reactor Power system (SRPS) are presented. The radiator consists of two sections; each serves an equal number of STMCs and has 162 longitudinal potassium heat pipes with 0.508 mm thick C-C fins. The width of the C-C fins at the minor diameter of the radiator is almost zero, but increases with distance along the radiator to reach 3.7 cm at the radiator's major diameter. The radiator's heat pipes (OD = 2.42 cm in front and 3.03 cm in rear) have thin titanium (0.0762 mm thick) liners and wicks (0.20 mm thick with an effective pore radius of 12-16 {mu}m) and a 1.016 mm thick C-C wall. The wick is separated from the titanium liner by a 0.4 mm annulus filled with liquid potassium to increase the capillary limit. The outer surfaces of the heat pipes in the front and rear sections of the radiator are protected with a C-C armor that is 2.17 mm and 1.70 mm thick, respectively. The inside surface of the heat pipes in the front radiator is thermally insulated while the C-C finned condensers of the rear heat pipes are exposed, radiating into space through the rear opening of the radiator cavity. The heat pipes in both the front and the rear radiators have a 1.5 m long evaporator section and each dissipates 4.47 kW while operating at 43.6% of the prevailing sonic limit. The front and rear radiator sections are 5.29 m and 2.61 m long with outer surface area and mass of 47.1 m2 and 314.3 kg, and 39.9 m2 and 243.2 kg, respectively. The total radiator is 7.63 m long and has minor and major diameters of 1.48 m and 5.57 m, respectively, and a total surface area of 87 m2; however, the effective radiator area, after accounting for heat rejection through the rear of the radiator cavity, is 98.8 m2. The radiator's total mass including the C-C armor is 557.5 kg and the specific area and specific mass are 6.41 kg/m2 and 5.07 kg/kWe, respectively.

El-Genk, Mohamed S.; Tournier, Jean-Michel [Institute for Space and Nuclear Power Studies, University of New Mexico, Albuquerque, NM, 87131 (United States); Chemical and Nuclear Engineering Dept., University of New Mexico, Albuquerque, NM, 87131 (United States)

2004-02-04

446

Performance evaluation of an UASB reactor used for combined treatment of domestic sewage and excess aerobic sludge from a trickling filter  

Microsoft Academic Search

This work aimed at evaluating the influence of the excess sludge produced in a trickling filter (TF) on the performance of a UASB reactor used for the combined treatment of domestic sewage and aerobic sludge. During phase 1 of the research, the UASB reactor\\/TF system was fed with domestic sewage pumped directly from the sewer collector of Arrudas stream, in

P. P. Pontes; C. A. L. Chernicharo; E. C. Frade; M. T. R. Porto

2003-01-01

447

The PC/Ecuador biogas program: considerations for future development  

SciTech Connect

Biogas, the production of methane fuel and fertilizer through the process of controlled anaerobic decomposition, has been one of the most controversial of the new renewable energy technologies. The integrated approach to fuel and fertilizer production, conservation and sanitation on a decentralized community level potentially holds great promise as a truly appropriate technology for rural development. The report presents the research, development, and demonstration of biogas technology conducted by the Peace Corps in Ecuador for the past six years.

Warpeha, P.R.

1980-06-28

448

Biological treatment of chicken feather waste for improved biogas production  

Microsoft Academic Search

A two-stage system was developed which combines the biological degradation of keratin-rich waste with the production of biogas. Chicken feather waste was treated biologically with a recombinant Bacillus megaterium strain showing keratinase activity prior to biogas production. Chopped, autoclaved chicken feathers (4%, W\\/V) were completely degraded, resulting in a yellowish fermentation broth with a level of 0.51 mg\\/mL soluble proteins

Gergely Forgács; Saeid Alinezhad; Amir Mirabdollah; Elisabeth Feuk-Lagerstedt; Ilona Sárvári Horváth

2011-01-01

449

Livestock-biogas-fruit systems in South China  

Microsoft Academic Search

Fruit farming and animal husbandry have existed for a long time in Meixian, Guangdong, South China. However, Meixian suffers from shortages of rural energy and organic fertilizer and from environmental pollution. A new eco-agricultural system, the livestock-biogas-fruit system, has been designed successfully in this region by adding biogas production to fight these problems. A study which was conducted in seven

Rongjun Chen

1997-01-01

450

Biogas recovery from microwave heated sludge by anaerobic digestion  

Microsoft Academic Search

Biogas generated from sewage sludge, livestock waste, and food waste by anaerobic digestion is a valuable renewable energy\\u000a resource. However, conventional anaerobic digestion is not an efficient process. A long hydraulic retention time and low biogas\\u000a recovery rate hinder the applications of those resources. An effective pretreatment method to destroy sludge microbial cells\\u000a has been one of the major concerns

Wei Qiao; Wei Wang; CuiPing Zhu; ZhongZhi Zhang

2010-01-01

451

Effect of biological pretreatments in enhancing corn straw biogas production  

Microsoft Academic Search

A biological pretreatment with new complex microbial agents was used to pretreat corn straw at ambient temperature (about 20°C) to improve its biodegradability and anaerobic biogas production. A complex microbial agent dose of 0.01% (w\\/w) and pretreatment time of 15days were appropriate for biological pretreatment. These treatment conditions resulted in 33.07% more total biogas yield, 75.57% more methane yield, and

Weizhang Zhong; Zhongzhi Zhang; Yijing Luo; Shanshan Sun; Wei Qiao; Meng Xiao

2011-01-01

452

Evaluating livestock manures for biogas production: a GIS based method  

Microsoft Academic Search

The Animals (data)Base for Energy Potential Estimation (ABEPE), presented in this paper, is a GIS based biomass resource assessment application using a relational database management system to estimate biogas production from livestock manures. Energy and biogas potential of livestock residues of all major groups of stock-raising animals (cattle, pigs, sheep\\/goats, poultry, etc.) were evaluated. The calculations were based on geographical

F. A. Batzias; D. K. Sidiras; E. K. Spyrou

2005-01-01

453

Biogas systems in India: is the technology appropriate  

SciTech Connect

Biogas technology is discussed as a possible solution to India's energy and fertilizer problems. The case of biogas systems in India illustrates that science and technology cannot be viewed apart from the social, economic, and political setting in which they are pursued. ''Appropriate'' technological solutions will be met with limited success or may even worsen the existing situation unless complementary structural changes in society are introduced at the same time.

Tucker, J.B.

1982-10-01

454

Extension of the TRANSURANUS code to the fuel rod performance analysis of LBE-cooled nuclear reactors  

NASA Astrophysics Data System (ADS)

This work intends to be a starting point for the extension of the TRANSURANUS fuel rod performance code to the modelling of the T91 steel, which is designed to be the cladding material in LBE (lead-bismuth eutectic) accelerator-driven systems (ADS). On the basis of the experimental data available in the recent literature on LBE and T91, a preliminary modelling of the T91 corrosion with flowing LBE under oxygen control is proposed, and the main issues (i.e., heat transfer, creep, swelling) relevant for the performance of this steel in a reactor are discussed, in order to be properly considered in TRANSURANUS.

Botazzoli, P.; Agosti, F.; di Marcello, V.; Luzzi, L.

455

Tritium Self-Sufficiency and Neutron Shielding Performance of Self-Cooled Liquid Blanket System for Helical Reactor  

SciTech Connect

Compatibility between tritium self-sufficiency and neutron shielding performance of self-cooled liquid blanket systems without solid neutron multiplier was investigated for the purpose of application to the conceptual helical reactor design of modified FFHR2 having the blanket space of 120 cm. The results of the neutronics calculation indicated that all of the Li/V-alloy, Flibe/V-alloy and Flibe/JLF-1 (Reduced Activation Ferritic steel) blankets are feasible for tritium breeding ability and neutron shielding performance. With the use of vanadium alloys, operation efficiency will be enhanced.

Tanaka, Teruya; Muroga, Takeo; Sagara, Akio [National Institute for Fusion Science (Japan)

2005-04-15

456

A Grid-based Virtual Reactor: Parallel performance and adaptive load balancing  

Microsoft Academic Search

We address the problem of porting parallel distributed applications from static homogeneous cluster environments to dynamic heterogeneous Grid resources. We introduce a generic technique for adaptive load balancing of parallel applications on heterogeneous resources and evaluate it using a case study application: a Virtual Reactor for simulation of plasma chemical vapour deposition. This application has a modular architecture with a

Vladimir V. Korkhov; Valeria V. Krzhizhanovskaya; Peter M. A. Sloot

2008-01-01

457

Effect of Gas Entrainment on Thermal-Hydraulic Performance of Sodium Cooled Reactor Core  

Microsoft Academic Search

With the view to determining whether or not gas entrained in the sodium coolant could cause overheating of a fast reactor core, the following items were studied:1. The effect of gas entrainment on the coolant flow rate and on coolant temperature rise.2. The effect of gas entrainment on the coolant heat transfer coefficient and film temperature drop.Equations were derived to

Masao HORI; A. J. FRIEDLAND

1970-01-01

458

On improving performance of Fischer-Tropsch synthesis, model studies on catalyst, reactor and process  

Microsoft Academic Search

The objective of this research is to improve the product quality and productivity of Fischer-Tropsch Synthesis (FTS) on cobalt catalysts for the production of diesel fuel. Model studies and designs are done on three different scales: catalyst, reactor and process. On the catalyst scale, in order to develop supported cobalt catalyst with both high activity and thermal and chemical stabilities,

Qiang Qin

2005-01-01

459

Emergy analysis of biogas systems based on different raw materials.  

PubMed

Environmental pollution and energy crisis restrict the development of China, and the utilization of renewable technology is an effective strategy to alleviate the damage. Biogas engineering has rapidly developed attributes to solve environmental problems and create a renewable energy product biogas. In this paper, two different biogas plants' materials were analyzed by emergy method. One of them is a biogas project whose degraded material is feces (BPF system), and the other is the one whose degraded material is corn straw (BPC system). As a result, the ecological-economic values of BPF and BPC are $28,300/yr and $8,100/yr, respectively. Considering currency, environment, and human inputs, both of the biogas projects have the ability of disposing waste and potential for development. The proportion of biogas output is much more than fertilizer output; so, fertilizer utilization should be emphasized in the future. In comparison, BPF is better than BPC in the aspects of ecological-economic benefits, environmental benefits, and sustainability. The reason is the difficulty of corn straw seasonal collection and degradation. Thus it is proposed that BPC should be combined with the other raw materials. PMID:23476134

Wang, Yang; Lin, Cong; Li, Jing; Duan, Na; Li, Xue; Fu, Yanyan

2013-02-14

460

Flame Stabilization on Microscopic Scale of Wet Biogas with Microflame  

NASA Astrophysics Data System (ADS)

Harvesting, transportation, energy conversion and the high-efficient utilization, cascade method and market formation besides become with the indispensable element in order to utilize the biomass resource. There are two type biogases; it is gasified gas from dried biomass by partially combustion and wet biogas from wet biomass by methane fermentation, especially from the livestock excrement resources. This paper discusses an experimental study for flame stabilization on microscopic scale with wet biogas (mainly 0.6CH4+0.4CO2). In this study, the microflame with the wet biogas fuels are formed by the diffusion flame on the coppered straight pipes of inner diameter 0.02mm ˜ 1.5mm. This study is obtained stability mapping on microscopic scale of formed microflame by wet biogas fuels. The flame stability limit conditions on microscopic scale of wet biogas is drawn with blow off and extinction flame double limit lines. It is suggested that minimum mixing spatial scale change by the each mixing ratio of the wet biogas.

Ida, Tamio; Fuchihata, Manabu; Mizuno, Satoru

461

Performance evaluation and kinetic modeling of the start-up of a UASB reactor treating municipal wastewater at low temperature.  

PubMed

A kinetic modeling-based study was carried out to evaluate the start-up performance of a 10-L up-flow anaerobic sludge blanket (UASB) reactor treating municipal wastewater under different organic and hydraulic loading conditions. The reactor was operated for 105 days (around 4 months) below 20 °C and with three different hydraulic retention times of 24, 12 and 5 h. Imposed volumetric organic loading rates (OLR) ranged from 0.57 (±0.05) to 11.78 (±0.85) kg TCOD/m(3)-day. Although relatively high incoming volumetric OLR values were employed to the system, the UASB reactor demonstrated a favorable performance on the anaerobic treatability of municipal wastewater, and no process failure was recorded in the start-up stage. On the basis of experimental results, the modified Stover-Kincannon model was successfully applied to define the start-up kinetics with a very high value of the correlation coefficient (R = 0.9729). Maximum substrate utilization rate constant and saturation constant of the modified Stover-Kincannon model were determined as U (max) = 1.996 g/L-day and K (B) = 1.536 g/L-day, respectively. PMID:20683617

Turkdogan-Aydinol, F Ilter; Yetilmezsoy, Kaan; Comez, Sezen; Bayhan, Hurrem

2010-08-04

462

Performance analysis of a Pb-Bi cooled fast reactor - PEACER-300 in proliferation resistance and transmutation aspects  

SciTech Connect

A design study of 850 MWt lead-bismuth cooled reactor cores is performed to maximize the transmutation of both TRU nuclides in homogeneous fuel pin and long-lived fission products in separate target pins. Transmutation of minor actinide under a closed recycling was analyzed with assumption that decontamination factors in pyro-reprocessing plant data be reasonably high. The optimized design parameter were chosen as of a flat core shape with 50 cm in active core height and 5 m in core diameter, loaded with 17 x 17 arrayed fuel assemblies. A pitch to diameter ratio is 2.2, operating coolant temperature range is 300 deg. C-400 deg. C, and core consists of 3 different enrichment zones with one year cycle length. In safety aspects, this core design satisfied large negative temperature feedback coefficients, and sufficient shutdown margin by primary shutdown system with 20 B{sub 4}C control assemblies and by secondary shutdown system with 40 w/o enriched 12 B{sub 4}C control assemblies. Performance of designed core showed a high transmutation capability with support ratio of 2.085 and less TEX values than other reactor types. Better proliferation resistance could be achieved than other reactor types. (authors)

Lim, J. Y.; Kim, M. H. [Dept. of Nuclear Engineering, Kyung Hee Univ., Yongin-shi, Gyeonggi-do, 449-701 (Korea, Republic of)

2006-07-01

463

Coal liquefaction. Investigation of reactor performance, role of catalysts and PCT properties. Quarterly progress report, April 1-June 30, 1986  

SciTech Connect

The objective of this work is to investigate areas of science and technology that have been defined as being of prime interest to coal processing technology development. These areas include properties of coal liquids and slurries, reactor design and performance in relation to reaction mechanisms. The work comprises investigations of the following high priority areas: (1) reaction kinetics and reactor performance in coal liquefaction; (2) role of catalysts in indirect liquefaction and direct coal liquefaction; and (3) physical, chemical and thermodynamic properties of coal liquefaction products. During this past quarter, major emphasis for task 1 was an obtaining hydrodynamic, mass transfer and mixing parameters for the description of the ebullated bed reactor. For task 2, a literature review of coal liquefaction catalysts was conducted. The review showed that there were two ways in which metal carbonyls had been used, as catalysts or catalyst precursors. Examples are cited. Also coal liquefaction with liquid clathrates was found to occur at or near room temperature and required neither application of heat nor consumption of hydrogen. A comparison of coal solution in different liquid clathrates for various ranks of coal is summarized in tabular form. 17 refs., 1 fig., 3 tabs.

Shah, Y.T.; Tierney, J.W.; Wender, I.; Joseph, S.; Wen, C.S.

1986-01-01

464

Performances of a full-scale novel multiplate anaerobic reactor treating cheese whey effluent.  

PubMed

A 450-m(3) multiplate anaerobic reactor (MPAR) has been started-up in April 1992 for treating wastewater (whey permeate and domestic wastewater) at the Nutrinor (Lactel) cheese factory in Chambord (Québec, Canada). The MPAR consists of four superimposed sections. The liquid flows upwards from one section to the next, while the gas is collected below each plate and evacuated through side-outlets. The wastewater is concurrently distributed at the bottom of the first, second, and third sections, as 50%, 33%, and 17% of the total influent stream, respectively. Granular anaerobic sludge at an initial concentration of 30 kg of volatile suspended solids (VSS) per cubic meter of reactor liquid volume was used to inoculate the reactor. Under normal operation of the factory, the chemical oxygen demand (COD) concentration of the influent ranged from 20 to 37 kg COD m(-3). The reactor organic loading rate (OLR) fluctuated between 9 and 14.7 kg COD m(-3) d(-1) for hydraulic retention times (HRT) maintained between 55 and 68 h. At the highest OLR, the MPAR showed an efficiency of 98% and 92% for soluble and total COD removal, respectively, and a methane production rate averaging around 4 m(3) m(-3) d(-1).Biomass-specific activities ranged between 7 and 51, 1.3 and 8.5, 5.3 and 12.2, 60 and 119, and 119 and 211 mmol g(-1) VSS d(-1) for glucose, propionate, acetate, formate, and hydrogen, respectively. Average equivalent-diameter of the granules was around 0.65 mm. The MPAR reactor generally showed a large capacity for solid retention with a biomass content between 32 and 37 kg VSS m(-3). PMID:18623232

Guiot, S R; Safi, B; Frigon, J C; Mercier, P; Mulligan, C; Tremblay, R; Samson, R

1995-03-01

465

Performance Specification Fuel Drying and Canister Inerting System for Shippingport Pressurized Water Reactor (PWR) Core 2 Blanket Fuel Assemblies Stored Within Shippingport Spent Fuel Canisters.  

National Technical Information Service (NTIS)

This specification establishes the performance requirements and basic design requirements imposed on the fuel drying and canister inerting system for Shippingport Pressurized Water Reactor (PWR) Core 2 blanket fuel assemblies (BFAs) stored within Shipping...

D. M. Johnson

2000-01-01

466