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1

Effect of post-digestion temperature on serial CSTR biogas reactor performance  

Microsoft Academic Search

The effect of post-digestion temperature on a lab-scale serial continuous-flow stirred tank reactor (CSTR) system performance was investigated. The system consisted of a main reactor operated at 55°C with hydraulic retention time (HRT) of 15 days followed by post-digestion reactors with HRT of 5.3 days. Three post-digestion temperatures (55°C, 37°C and 15°C) were compared in terms of biogas production, process

Kanokwan Boe; Dimitar Karakashev; Eric Trably; Irini Angelidaki

2009-01-01

2

Methanogenesis in thermophilic biogas reactors  

Microsoft Academic Search

Methanogenesis in thermophilic biogas reactors fed with different wastes is examined. The specific methanogenic activity with acetate or hydrogen as substrate reflected the organic loading of the specific reactor examined. Increasing the loading of thermophilic reactors stabilized the process as indicated by a lower concentration of volatile fatty acids in the effluent from the reactors. The specific methanogenic activity in

Birgitte Kiær Ahring

1995-01-01

3

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

2013-10-01

4

Mesophilic syntrophic acetate oxidation during methane formation in biogas reactors  

Microsoft Academic Search

The reaction pathway for the formation of methane from acetate was investigated in sludge from 13 different biogas reactors. By following the conversion of [2-14C]acetate and [14C]bicarbonate it was shown that methane formation by syntrophic acetate oxidation was the dominating mechanism for acetotrophic methanogenesis in sludge containing high levels of salts, mainly ammonium, and volatile fatty acids. In one biogas

Anna Schnürer; Gerhard Zellner; Bo H. Svensson

1999-01-01

5

Multiscale hydrodynamic investigation to intensify the biogas production in upflow anaerobic reactors.  

PubMed

Hydrodynamics plays a main role for the performance of an anaerobic reactor involving three phases: wastewater, sludge granules and biogas bubbles. The present work was focused on an original approach to investigate the hydrodynamics at different scales and then to intensify the performance of such complex reactors. The experiments were carried out respectively in a 3D reactor at macroscale, a 2D reactor at mesoscale and a 1D anaerobic reactor at microscale. A Particle Image Velocimetry (PIV), a micro-PIV and a high-speed camera were employed to quantify the liquid flow fields and the relative motion between sludge granules and bubbles. Shear rates exerted on sludge granules were quantified from liquid flow fields. The optimal biogas production is obtained at mean shear rate varying from 28 to 48s(-1), which is controlled by two antagonistic mechanisms. The multiscale approach demonstrates pertinent mechanisms proper to each scale and allows a better understanding of such reactors. PMID:24398185

Jiang, Jiankai; Wu, Jing; Zhang, Jinbai; Poncin, Souhila; Li, Huai Z

2014-03-01

6

Ilchmann, Achim; Pahl, M. : Adaptive Multivariable pH Regulation of a Biogas Tower Reactor  

E-print Network

Ilchmann, Achim; Pahl, M. : Adaptive Multivariable pH Regulation of a Biogas Tower Reactor Zuerst. The adaptive controller was successlullytesteclover il pcriod of tu'o nonths at a biogas tower reuetoriu pilot are not applicable to the biogas tower reüctor.since a dontinatingf-eatureof the new reactol' prir-rciplc-is its

Knobloch,Jürgen

7

Effect of reactor configuration on biogas production from wheat straw hydrolysate.  

PubMed

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 degrees C for 10-12 min) for producing 2nd generation bioethanol [Kaparaju, P., Serrano, M., Thomsen, A.B., Kongjan, P., Angelidaki, I., 2009. Bioethanol, biohydrogen and biogas production from wheat straw in a biorefinery concept. Bioresource Technology 100 (9), 2562-2568]. Results from batch assays showed that hydrolysate had a methane potential of 384 ml/g-volatile solids (VS)(added). Process performance in CTSR and UASB reactors was investigated by varying hydrolysate concentration and/or organic loading rate (OLR). In CSTR, methane yields increased with increase in hydrolysate concentration and maximum yield of 297 ml/g-COD was obtained at an OLR of 1.9 g-COD/l d and 100% (v/v) hydrolysate. On the other hand, process performance and methane yields in UASB were affected by OLR and/or substrate concentration. Maximum methane yields of 267 ml/g-COD (COD removal of 72%) was obtained in UASB reactor when operated at an OLR of 2.8 g-COD/l d but with only 10% (v/v) hydrolysate. However, co-digestion of hydrolysate with pig manure (1:3 v/v ratio) improved the process performance and resulted in methane yield of 219 ml/g-COD (COD removal of 72%). Thus, anaerobic digestion of hydrolysate for biogas production was feasible in both CSTR and UASB reactor types. However, biogas process was affected by the reactor type and operating conditions. PMID:19647428

Kaparaju, Prasad; Serrano, María; Angelidaki, Irini

2009-12-01

8

Bioaugmentation of syntrophic acetate-oxidizing culture in biogas reactors exposed to increasing levels of ammonia.  

PubMed

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 NH(4)(+)-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. PMID:22923397

Westerholm, Maria; Levén, Lotta; Schnürer, Anna

2012-11-01

9

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. PMID:22923397

Westerholm, Maria; Leven, Lotta

2012-01-01

10

Autogenerative high pressure digestion: anaerobic digestion and biogas upgrading in a single step reactor system.  

PubMed

Conventional anaerobic digestion is a widely applied technology to produce biogas from organic wastes and residues. The biogas calorific value depends on the CH, content which generally ranges between 55 and 65%. Biogas upgrading to so-called 'green gas', with natural gas quality, generally proceeds with add-on technologies, applicable only for biogas flows > 100 m3/h. In the concept of autogenerative high pressure digestion (AHPD), methanogenic biomass builds up pressure inside the reactor. Since CO2 has a higher solubility than CH4, it will proportion more to the liquid phase at higher pressures. Therefore, AHPD biogas is characterised by a high CH4 content, reaching equilibrium values between 90 and 95% at a pressure of 3-90 bar. In addition, also H2S and NH3 are theoretically more soluble in the bulk liquid than CO2. Moreover, the water content of the already compressed biogas is calculated to have a dew point <--10 degrees C. Ideally, high-quality biogas can be directly used for electricity and heat generation, or injected in a local natural gas distribution net. In the present study, using sodium acetate as substrate and anaerobic granular sludge as inoculum, batch-fed reactors showed a pressure increase up to 90 bars, the maximum allowable value for our used reactors. However, the specific methanogenic activity (SMA) of the sludge decreased on average by 30% compared to digestion at ambient pressure (1 bar). Other results show no effect of pressure exposure on the SMA assessed under atmospheric conditions. These first results show that the proposed AHPD process is a highly promising technology for anaerobic digestion and biogas upgrading in a single step reactor system. PMID:22097043

Lindeboom, R E F; Fermoso, F G; Weijma, J; Zagt, K; van Lier, J B

2011-01-01

11

Performance evaluation of Janata and Deenbandhu biogas plants  

SciTech Connect

Performance of the Janata and Deenbandhu fixed dome biogas plants for anaerobic digestion of dairy manure was evaluated under the conditions of a hilly region. In contrast to Janata, the Deenbandhu biogas plant was found to be not only cheaper on the basis of cost/m{sup 3} rated capacity of the plant, but it also produced more gas per unit of manure fed and per unit of digester volume in addition to maintaining a consistent rate of gas production during subsequent years from initial charging. The higher production of gas by 28.5% and 12.5% per kg of manure fed and 49.5% and 28.9% per m{sup 3} of digester volume was observed from this plant for highest 24 C and lowest 14 C digester temperatures of the plants for the months of July and December, respectively.

Kalia, A.K.; Kanwar, S.S. [H P Krishi Vishvavidyalaya, Palampur (India). Dept. of Agricultural Engineering

1996-04-01

12

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

13

Influences of the substrate feeding regime on methanogenic activity in biogas reactors approached by molecular and stable isotope methods.  

PubMed

In order to better understand the effects of the substrate feeding regime on methanogenesis during anaerobic digestion in biogas reactors, four continuous stirred tank reactors operated under mesophilic conditions were investigated. In addition to standard physicochemical parameters, the stable isotopic signatures of CH4 and CO2 before and after daily feeding were analyzed. The activity of the methanogens was assessed by methyl coenzyme M reductase alpha-subunit (mcrA/mrtA) gene transcript analysis. Two different feeding regimes i.e. single vs. double consecutive feeding of the otherwise same daily maize silage load were investigated. During the first phase, a single feeding of the whole daily dose increased the biogas production within 70-80 min from around 0.5 to 2.0 L/h. This increase was associated with a transient increase of the acetic acid concentration and a corresponding decrease of the pH. Only moderate increase in biogas yield and VFA concentration (mainly acetate) was observed when the daily substrate was apportioned into two feedings. However, the overall daily gas production was similar in both cases. Regardless of the feeding regime, significantly depleted ?(13)CH4 and minor changes in the CO2 content of biogas were observed after feeding, which were followed by enrichment of ?(13)CH4. This period was associated with detectable changes in activity of methanogenic communities monitored by terminal restriction fragment length polymorphism analysis based on the transcripts of mcrA/mrtA genes. Methanoculleus and Methanobacterium spp. were the predominant methanogens in all reactors, while Methanosarcina spp. activity was only significant in two reactors. The activity of Methanoculleus and Methanosarcina spp. increased after the feeding in these reactors, which was followed by a depletion of ?(13)C in the produced gas. In both reactors, the less depleted isotopic values were detected before the second feeding, when Methanobacterium was the most active genus. Variations in reactor performance and methanogenic community characteristics were attributed to inoculum heterogeneity and stochastic factors during the reactor set up. PMID:24291758

Lv, Z; Leite, A F; Harms, H; Richnow, H H; Liebetrau, J; Nikolausz, M

2014-10-01

14

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

15

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 3.5 g 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

2013-09-01

16

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

17

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. PMID:22247168

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

2012-01-01

18

Strategies for recovering inhibition caused by long chain fatty acids on anaerobic thermophilic biogas reactors  

Microsoft Academic Search

Long chain fatty acids (LCFA) concentrations over 1.0gL?1 were inhibiting manure thermophilic digestion, in batch and semi-continuous experiments, resulting in a temporary cease of the biogas production. The aim of the work was to test and evaluate several recovery actions, such as reactor feeding patterns, dilution and addition of adsorbents, in order to determine the most appropriate strategy for fast

J. Palatsi; M. Laureni; M. V. Andrés; X. Flotats; H. B. Nielsen; I. Angelidaki

2009-01-01

19

Cryptococcus shivajii sp. nov.: A Novel Basidiomycetous Yeast Isolated from Biogas Reactor  

Microsoft Academic Search

Five yeast morphotypes were isolated from biogas reactors at North Wyke Research, Okehampton, UK. Out of the five morphotypes,\\u000a four were identified as known species. In contrast, the fifth morphotype strain, Bio10T, was found to differ from Bullera dendrophila and Kwoniella mangroviensis, its closest phylogenetic neighbours, by 2.6–2.9% with respect to the nucleotide sequence of the D1\\/D2 domain of the

Sreenivas Rao Ravella; Stephen A. James; Christopher J. Bond; Ian N. Roberts; Kathryn Cross; Andy Retter; Phil J. Hobbs

2010-01-01

20

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

21

Identical full-scale biogas-lift reactors (Blrs) with anaerobic granular sludge and residual activated sludge for brewery wastewater treatment and kinetic modeling.  

PubMed

Two identical full-scale biogas-lift reactors treating brewery wastewater were inoculated with different types of sludge to compare their operational conditions, sludge characteristics, and kinetic models at a mesophilic temperature. One reactor (R1) started up with anaerobic granular sludge in 12 weeks and obtained a continuously average organic loading rate (OLR) of 7.4 kg chemical oxygen demand (COD)/(m3 x day), COD removal efficiency of 80%, and effluent COD of 450 mg/L. The other reactor (R2) started up with residual activated sludge in 30 weeks and granulation accomplished when the reactor reached an average OLR of 8.3 kg COD/(m3 x day), COD removal efficiency of 90%, and effluent COD of 240 mg/L. Differences in sludge characteristics, biogas compositions, and biogas-lift processes may be accounted for the superior efficiency of the treatment performance of R2 over R1. Grau second-order and modified StoverKincannon models based on influent and effluent concentrations as well as hydraulic retention time were successfully used to develop kinetic parameters of the experimental data with high correlation coefficients (R2 > 0.95), which further showed that R2 had higher treatment performance than R1. These results demonstrated that residual activated sludge could be used effectively instead of anaerobic granular sludge despite the need for a longer time. PMID:24494489

Xu, Fu; Huang, Zhenxing; Miao, Hengfeng; Ren, Hongyan; Zhao, Mingxing; Ruan, Wenquan

2013-10-01

22

Wood ash amendment to biogas reactors as an alternative to landfilling? A preliminary study on changes in process chemistry and biology.  

PubMed

Wood ash addition to biogas plants represents an alternative to commonly used landfilling by improving the reactor performance, raising the pH and alleviating potential limits of trace elements. This study is the first on the effects of wood ash on reactor conditions and microbial communities in cattle slurry-based biogas reactors. General process parameters [temperature, pH, electrical conductivity, ammonia, volatile fatty acids, carbon/nitrogen (C/N), total solids (TS), volatile solids, and gas quantity and quality] were monitored along with molecular analyses of methanogens by polymerase chain reaction- denaturing gradient gel electrophoresis and modern microarrays (archaea and bacteria). A prompt pH rise was observed, as was an increase in C/N ratio and volatile fatty acids. Biogas production was inhibited, but recovered to even higher production rates and methane concentration after single amendment. High sulphur levels in the wood ash generated hydrogen sulphide and potentially hampered methanogenesis. Methanosarcina was the most dominant methanogen in all reactors; however, diversity was higher in ash-amended reactors. Bacterial groups like Firmicutes, Proteobacteria and Acidobacteria were favoured, which could improve the hydrolytic efficiency of the reactors. We recommend constant monitoring of the chemical composition of the used wood ash and suggest that ash amendment is adequate if added to the substrate at a rate low enough to allow adaptation of the microbiota (e.g. 0.25 g g(-1) TS). It could further help to enrich digestate with important nutrients, for example phosphorus, calcium and magnesium, but further experiments are required for the evaluation of wood ash concentrations that are tolerable for anaerobic digestion. PMID:23831776

Podmirseg, Sabine M; Seewald, Martin S A; Knapp, Brigitte A; Bouzid, Ourdia; Biderre-Petit, Corinne; Peyret, Pierre; Insam, Heribert

2013-08-01

23

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

24

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

25

Performance and emission characteristics of a SI engine fueled by low calorific biogas blended with hydrogen  

Microsoft Academic Search

In this study, an experimental investigation on a naturally aspirated (NA), 8-L spark ignition engine fueled by biogas with various methane concentrations – which we called the N2 dilution test – was performed in terms of its thermal efficiency, combustion characteristics and emissions. The engine was operated at a constant engine rotational speed of 1800 rpm under a 60 kW power output

Seunghyun Park; Yonggyu Lee; Changgi Kim; Sunyoup Lee; Yasuo Moriyoshi

2011-01-01

26

Effect of carbon dioxide on the performance of biogas\\/diesel duel-fuel engine  

Microsoft Academic Search

Methane and carbon dioxide are the two main constituents of biogas. Biogas also contains traces of nitrogen, hydrogen, oxygen and hydrogen sulphide. When diesel engine runs on biogas, the combustion is poor as compared to diesel fuel. One of the reason of poor combustion is the presence of carbon dioxide in the biogas. Percentage of methane and carbon dioxide in

Saiful Bari

1996-01-01

27

Performance of semi-continuous membrane bioreactor in biogas production from toxic feedstock containing D-Limonene.  

PubMed

A novel membrane bioreactor configuration containing both free and encased cells in a single reactor was proposed in this work. The reactor consisted of 120g/L of free cells and 120g/L of encased cells in a polyvinylidene fluoride membrane. Microcrystalline cellulose (Avicel) and d-Limonene were used as the models of substrate and inhibitor for biogas production, respectively. Different concentrations of d-Limonene i.e., 1, 5, and 10g/L were tested, and an experiment without the addition of d-Limonene was prepared as control. The digestion was performed in a semi-continuous thermophilic reactor for 75 days. The result showed that daily methane production in the reactor with the addition of 1g/L d-Limonene was similar to that of control. A lag phase was observed in the presence of 5g/L d-Limonene; however, after 10 days, the methane production increased and reached a similar production to that of the control after 15 days. PMID:25151080

Wikandari, Rachma; Youngsukkasem, Supansa; Millati, Ria; Taherzadeh, Mohammad J

2014-10-01

28

A highly thermoactive and salt-tolerant ?-amylase isolated from a pilot-plant biogas reactor.  

PubMed

Aiming at the isolation of novel enzymes from previously uncultured thermophilic microorganisms, a metagenome library was constructed from DNA isolated from a pilot-plant biogas reactor operating at 55 °C. The library was screened for starch-degrading enzymes, and one active clone was found. An open reading frame of 1,461 bp encoding an ?-amylase from an uncultured organism was identified. The amy13A gene was cloned in Escherichia coli, resulting in high-level expression of the recombinant amylase. The novel enzyme Amy13A showed the highest sequence identity (75%) to ?-amylases from Petrotoga mobilis and Halothermothrix orenii. Amy13A is highly thermoactive, exhibiting optimal activity at 80 °C, and it is also highly salt-tolerant, being active in 25% (w/v) NaCl. Amy13A is one of the few enzymes that tolerate high concentrations of salt and elevated temperatures, making it a potential candidate for starch processing under extreme conditions. PMID:22743714

Jabbour, Dina; Sorger, Anneke; Sahm, Kerstin; Antranikian, Garabed

2013-04-01

29

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

30

Aerobic desulfurization of biogas by acidic biotrickling filtration in a randomly packed reactor.  

PubMed

Biotrickling filters for biogas desulfurization still must prove their stability and robustness in the long run under extreme conditions. Long-term desulfurization of high loads of H2S under acidic pH was studied in a lab-scale aerobic biotrickling filter packed with metallic Pall rings. Reference operating conditions at steady-state corresponded to an empty bed residence time (EBRT) of 130s, H2S loading rate of 52gS-H2Sm(-3)h(-1) and pH 2.50-2.75. The EBRT reduction showed that the critical EBRT was 75s and the maximum EC 100gS-H2Sm(-3)h(-1). Stepwise increases of the inlet H2S concentration up to 10,000ppmv lead to a maximum EC of 220gS-H2Sm(-3)h(-1). The H2S removal profile along the filter bed indicated that the first third of the filter bed was responsible for 70-80% of the total H2S removal. The oxidation rate of solid sulfur accumulated inside the bioreactor during periodical H2S starvation episodes was verified under acidic operating conditions. The performance under acidic pH was comparable to that under neutral pH in terms of H2S removal capacity. However, bioleaching of the metallic packing used as support and chemical precipitation of sulfide/sulfur salts occurred. PMID:25151242

Montebello, Andrea M; Mora, Mabel; López, Luis R; Bezerra, Tercia; Gamisans, Xavier; Lafuente, Javier; Baeza, Mireia; Gabriel, David

2014-09-15

31

Microbial community composition and dynamics in high-temperature biogas reactors using industrial bioethanol waste as substrate.  

PubMed

Stillage, which is generated during bioethanol production, constitutes a promising substrate for biogas production within the scope of an integrated biorefinery concept. In this study, a microbial community was grown on thin stillage as mono-substrate in a continuous stirred tank reactor (CSTR) at a constant temperature of 55 °C, at an organic loading rate of 1.5 goTS/L*d and a retention time of 25 days. Using an amplicon-based dataset of 17,400 high-quality sequences of 16S rRNA gene fragments (V2-V3 regions), predominance of Bacteria assigned to the families Thermotogaceae and Elusimicrobiaceae was detected. Dominant members of methane-producing Euryarchaeota within the CSTR belonged to obligate acetoclastic Methanosaetaceae and hydrogenotrophic Methanobacteriaceae. In order to investigate population dynamics during reactor acidification, the organic loading rate was increased abruptly, which resulted in an elevated concentration of volatile fatty acids. Acidification led to a decrease in relative abundance of Bacteria accompanied with stable numbers of Archaea. Nevertheless, the abundance of Methanosaetaceae increased while that of Methanobacteriales decreased successively. These findings demonstrate that a profound intervention to the biogas process may result in persistent community changes and reveals uncommon bacterial families as process-relevant microorganisms. PMID:25012784

Röske, Immo; Sabra, Wael; Nacke, Heiko; Daniel, Rolf; Zeng, An-Ping; Antranikian, Garabed; Sahm, Kerstin

2014-11-01

32

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

33

A dual purpose packed-bed reactor for biogas scrubbing and methane-dependent water quality improvement applying to a wastewater treatment system consisting of UASB reactor and trickling filter.  

PubMed

A wastewater treatment system employing a UASB reactor in temperate regions requires biogas as a heat source for the UASB reactor during low temperature seasons. In this case, removal of H2S in the biogas by means of a scrubber before burning is necessary in order to prevent the boilers from corroding. Heating of the UASB reactor is, however, unnecessary in a warm season, and the scrubber and biogas become useless. Methane-dependent water quality improvement using the scrubber and biogas would be one way to use them efficiently during the warm season. The possible dual-purpose use of a packed-bed reactor was examined, with one of its uses being the scrubbing of biogas during the cold season and the other being the methane-dependent improvement of effluent water quality during the warm season. A bench scale packed-bed filled with plastic latticed-ring media was installed in a livestock wastewater treatment plant consisting of a UASB reactor and a trickling filter for post-treatment. The packed-bed was operated with biogas flowing at a superficial velocity of 0.14-0.39 m h(-1) and the hydraulic loading of trickling filter effluent sprayed onto the media 9.4-26.1 m3 m2 day(-1). H2S in the biogas from the UASB reactor was reduced from 1,200-2,500 ppm to less than 2 ppm by the reactor. Methane-dependent water quality improvement was examined using a laboratory scale reactor to which methane and/or air was supplied from the bottom, while plant effluent was spread from the top of the reactor. When the mixture gas of methane and air (volume ratio 1:3) was added to the reactor, biofilm grew on the surface of the media. Accompanying this growth, ammonium and phosphate in the spread water decreased, probably due to assimilation by the methane-oxidizing bacteria. Though assimilation activity dropped after the accumulation of biomass, it could be reactivated by washing out the excess biomass. Periodical backwash at a rate of more than once a week seemed to efficiently maintain the removal activity. The dark brown color of the wastewater could be also reduced in concert with methane oxidation. It seemed that methane-oxidizing bacteria degraded color-causing compounds. These results suggest that the packed-bed reactor is useful for both H2S purification of biogas and methane-dependent effluent water quality improvement. PMID:12137264

Tanaka, Yasuo

2002-08-01

34

Utilization of high-strength wastewater for the production of biogas as a renewable energy source using hybrid upflow anaerobic sludge blanket (HUASB) reactor  

SciTech Connect

Anaerobic digestion of distillery spentwash, a high-strength wastewater, was studied using a hybrid upflow anaerobic sludge blanket (HUASB) reactor for 240 days under ambient conditions. The HUASB reactor combined an open volume in the bottom two-thirds of the reactor for sludge blanket and polypropylene pall rings packing in the upper one-third of the reactor. The aim of the study was to achieve optimum biogas production and waste treatment. Using non-granular anaerobic sewage sludge as seed, the start-up of the HUASB reactor was successfully completed, with the production of active bacterial granules of 1--2 mm size, within 90 days. Examination of the bacterial granules under scanning electron microscope (SEM) revealed that Methanothrix like microorganisms were the dominant species besides Methanosarcina. An organic loading of 24 kg COD/m{sup 3}d at a low hydraulic retention time (HRT) of 6 hours was achieved with 82% reduction in COD. Biogas with high methane content (80%) was produced at these loadings. The specific biogas yield was 0.36 m{sup 3} CH{sub 4}/kg COD. Packing in the upper third of the reactor was very efficient as a gas-solid separator (GSS); and in addition it retained the biomass.

Shivayogimath, C.B.; Ramanujam, T.K.

1998-07-01

35

Managing Manure with Biogas Recovery Systems  

E-print Network

Managing Manure with Biogas Recovery Systems Improved Performance at Competitive Costs 1EPA United is managing manure and process water in a way that controls odors and protects environ- mental quality. Biogas emissions and capture biogas--a useful source of energy. About Anaerobic Digestion Biogas recovery systems

Mukhtar, Saqib

36

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. PMID:23557021

2013-01-01

37

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

38

Biogas utilization  

SciTech Connect

Options for successfully using biogas depend on project scale. Almost all biogas from anaerobic digesters must first go through a gas handling system that pressurizes, meters, and filters the biogas. Additional treatment, including hydrogen sulfide-mercaptan scrubbing, gas drying, and carbon dioxide removal may be necessary for specialized uses, but these are complex and expensive processes. Thus, they can be justified only for large-scale projects that require high-quality biogas. Small-scale projects (less than 65 cfm) generally use biogas (as produced) as a boiler fuel or for fueling internal combustion engine-generators to produce electricity. If engines or boilers are selected properly, there should be no need to remove hydrogen sulfide. Small-scale combustion turbines, steam turbines, and fuel cells are not used because of their technical complexity and high capital cost. Biogas cleanup to pipeline or transportation fuel specifications is very costly, and energy economics preclude this level of treatment.

Moser, M.A. [Resource Conservation Management, Inc., Berkeley, CA (United States)

1996-01-01

39

Co-digestion of manure and whey for in situ biogas upgrading by the addition of H(2): process performance and microbial insights.  

PubMed

In situ biogas upgrading was conducted by introducing H(2) directly to the anaerobic reactor. As H(2) addition is associated with consumption of the CO(2) in the biogas reactor, pH increased to higher than 8.0 when manure alone was used as substrate. By co-digestion of manure with acidic whey, the pH in the anaerobic reactor with the addition of hydrogen could be maintained below 8.0, which did not have inhibition to the anaerobic process. The H(2) distribution systems (diffusers with different pore sizes) and liquid mixing intensities were demonstrated to affect the gas-liquid mass transfer of H(2) and the biogas composition. The best biogas composition (75:6.6:18.4) was obtained at stirring speed 150 rpm and using ceramic diffuser, while the biogas in the control reactor consisted of CH(4) and CO(2) at a ratio of 55:45. The consumed hydrogen was almost completely converted to CH(4), and there was no significant accumulation of VFA in the effluent. The study showed that addition of hydrogen had positive effect on the methanogenesis, but had no obvious effect on the acetogenesis. Both hydrogenotrophic methanogenic activity and the concentration of coenzyme F(420) involved in methanogenesis were increased. The archaeal community was also altered with the addition of hydrogen, and a Methanothermobacter thermautotrophicus related band appeared in a denaturing gradient gel electrophoresis gel from the sample of the reactor with hydrogen addition. Though the addition of hydrogen increased the dissolved hydrogen concentration, the degradation of propionate was still thermodynamically feasible at the reactor conditions. PMID:23143533

Luo, Gang; Angelidaki, Irini

2013-02-01

40

Biogas utilization  

SciTech Connect

Options for successfully using biomass depend on project scale. Almost all biogas from anaerobic digesters must first go through a gas handling system that pressurizes, meters, and filters the biogas. Additional treatment, including hydrogen sulfide-mercaptan scrubbing, gas drying, and carbon dioxide removal may be necessary for specialized uses, but these are complex and expensive processes. Thus, they can be justified only for large-scale projects that require high-quality biogas. Small-scale projects (less than 65 cfm) generally use biogas (as produced) as a boiler fuel or for fueling internal combustion engine generators to produce electricity. If engines or boilers as selected properly, there should be no need to remove hydrogen sulfide. Small-scale combustion turbines, steam turbines, and fuel cells are not used because of their technical complexity and high capital cost. Biogas cleanup to pipeline or transportation fuel specification is very costly, and energy economics preclude this level of treatment.

Moser, M.A. [Resource Conservation Management, Inc., Berkeley, CA (United States)

1995-11-01

41

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

42

Short-term effect of acetate and ethanol on methane formation in biogas sludge.  

PubMed

Biochemical processes in biogas plants are still not fully understood. Especially, the identification of possible bottlenecks in the complex fermentation processes during biogas production might provide potential to increase the performance of biogas plants. To shed light on the question which group of organism constitutes the limiting factor in the anaerobic breakdown of organic material, biogas sludge from different mesophilic biogas plants was examined under various conditions. Therefore, biogas sludge was incubated and analyzed in anaerobic serum flasks under an atmosphere of N2/CO2. The batch reactors mirrored the conditions and the performance of the full-scale biogas plants and were suitable test systems for a period of 24 h. Methane production rates were compared after supplementation with substrates for syntrophic bacteria, such as butyrate, propionate, or ethanol, as well as with acetate and H2+CO2 as substrates for methanogenic archaea. Methane formation rates increased significantly by 35 to 126 % when sludge from different biogas plants was supplemented with acetate or ethanol. The stability of important process parameters such as concentration of volatile fatty acids and pH indicate that ethanol and acetate increase biogas formation without affecting normally occurring fermentation processes. In contrast to ethanol or acetate, other fermentation products such as propionate, butyrate, or H2 did not result in increased methane formation rates. These results provide evidence that aceticlastic methanogenesis and ethanol-oxidizing syntrophic bacteria are not the limiting factor during biogas formation, respectively, and that biogas plant optimization is possible with special focus on methanogenesis from acetate. PMID:24903810

Refai, Sarah; Wassmann, Kati; Deppenmeier, Uwe

2014-08-01

43

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

2013-01-01

44

Treatment of Biogas Produced in Anaerobic Reactors for Domestic Wastewater: Odor Control and Energy\\/Resource Recovery  

Microsoft Academic Search

Anaerobic municipal wastewater treatment in developing countries has important potential applications considering their huge\\u000a lack of sanitation infrastructure and their advantageous climatic conditions. At present, among the obstacles that this technology\\u000a encounters, odor control and biogas utilization or disposal should be properly addressed. In fact, in most of small and medium\\u000a size anaerobic municipal treatment plants, biogas is just vented,

Adalberto Noyola; Juan Manuel Morgan-Sagastume; Jorge E. López-Hernández

2006-01-01

45

Improvement of biogas production by bioaugmentation.  

PubMed

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. PMID:23484123

Kovács, K L; Ács, N; Kovács, E; Wirth, R; Rákhely, G; Strang, Orsolya; Herbel, Zsófia; Bagi, Z

2013-01-01

46

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

47

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

48

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

49

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. PMID:23320936

2013-01-01

50

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

51

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

2013-12-01

52

Nuclear fuel performance in boiling water reactors  

SciTech Connect

A major development program is described to improve the performance of Boiling Water Reactor fuel. This sustained program is described in four parts: 1) performance monitoring, 2) fuel design changes, 3) plant operating recommendations, and 4) advanced fuel programs.

Elkins, R.B.; Baily, W.E.; Proebstle, R.A.; Armijo, J.S.; Klepfer, H.H.

1981-08-01

53

Performance evaluation of different configurations of biogas-fuelled SOFC micro-CHP systems for residential applications  

Microsoft Academic Search

Three configurations of solid oxide fuel cell (SOFC) micro-combined heat and power (micro-CHP) systems are studied with a particular emphasis on the application for single-family detached dwellings. Biogas is considered to be the primary fuel for the systems studied. In each system, a different method is used for processing the biogas fuel to prevent carbon deposition over the anode of the

Siamak Farhad; Feridun Hamdullahpur; Yeong Yoo

2010-01-01

54

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

55

Argonne National Laboratory's Reactor Performance  

E-print Network

" the physical processes that occur in a nuclear reactor core, including neutron transport, thermal hydraulics transitional tools to aid industry's migration to future commercially viable petascale computing platforms supported by industrial collaborators and related Department of Energy research programs. 1. Analysis

Kemner, Ken

56

Anaerobic digestion as final step of a cellulosic ethanol biorefinery: Biogas production from fermentation effluent in a UASB reactor-pilot-scale results.  

PubMed

In order to lower the costs for second generation bioethanol from lignocellulosic biomass anaerobic digestion of the effluent from ethanol fermentation was implemented using an upflow anaerobic sludge blanket (UASB) reactor system in a pilot-scale biorefinery plant. Both thermophilic (53 degrees C) and mesophilic (38 degrees C) operation of the UASB reactor was investigated. At an OLR of 3.5 kg-VS/(m(3) day) a methane yield of 340 L/kg-VS was achieved for thermophilic operation (53 degrees C) while 270 L/kg-VS was obtained under mesophilic conditions (38 degrees C). For loading rates higher than 5 kg-VS/(m(3) day) the methane yields were, however, higher under mesophilic conditions compared to thermophilic conditions. The conversion of dissolved organic matter (VS(diss)) was between 68% and 91%. The effluent from the ethanol fermentation showed no signs of toxicity to the anaerobic microorganisms. However, a high content of suspended matter reduced the degradation efficiency. The retention time of the anaerobic system could be reduced from 70 to 7 h by additional removal of suspended matter by clarification. Implementation of the biogas production from the fermentation effluent accounted for about 30% higher carbon utilization in the biorefinery compared to a system with only bioethanol production. PMID:20506521

Uellendahl, H; Ahring, B K

2010-09-01

57

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

58

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

59

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

60

Performance comparison between mesophilic and thermophilic anaerobic reactors for treatment of palm oil mill effluent.  

PubMed

The anaerobic digestion of palm oil mill effluent (POME) was carried out under mesophilic (37°C) and thermophilic (55°C) conditions without long-time POME storage in order to compare the performance of each condition in the field of Sumatra Island, Indonesia. The anaerobic treatment system was composed of anaerobic hybrid reactor and anaerobic baffled filter. Raw POME was pretreated by screw decanter to reduce suspended solids and residual oil. The total COD removal rate of 90-95% was achieved in both conditions at the OLR of 15kg[COD]/m(3)/d. The COD removal in thermophilic conditions was slightly better, however the biogas production was much higher than that in the mesophilic one at high OLR. The organic contents in pretreated POME were highly biodegradable in mesophilic under the lower OLRs. The biogas production was 13.5-20.0l/d at the 15kg[COD]/m(3)/d OLR, and the average content of carbon dioxide was 5-35% in both conditions. PMID:24797939

Jeong, Joo-Young; Son, Sung-Min; Pyon, Jun-Hyeon; Park, Joo-Yang

2014-08-01

61

Kinetic evaluation and process performance of an upflow anaerobic filter reactor degrading terephthalic acid.  

PubMed

The anaerobic degradation of terephthalic acid (TA) as the sole organic carbon source was studied in an upflow anaerobic filter (UAF) reactor. The reactor was seeded with biomass obtained from a full-scale upflow anaerobic sludge bed (UASB) reactor and was used to treat wastewater from a petrochemical facility producing dimethyl terephthalate. The UAF reactor was operated for 252 d with a constant hydraulic retention time of 24 h, and the organic loading rate (OLR) was gradually increased from 1 to 10 g-chemical oxygen demand (COD)/L d. After a lag period of approximately 40 d, the COD removal efficiency increased exponentially and high removal rate values (?90%) were obtained, except for at highest OLR (10 g-COD/L d). The high removal rates and the robustness of the reactor performance could be attributed to the formation of biofilm as well as granular sludge. The methane production rates (0.22 to 2.15 L/d) correlated well with the removed OLRs (0.3 to 6.8 g-COD/L d) during the various phases of treatment, indicating that the main mechanism of TA degradation occurs via methanogenic reactions. The average methane content of the produced biogas was 70.3%. The modified Stover-Kincannon model was found to be applicable for the anaerobic degradation of TA in UAFs (Umax = 64.5, KB = 69.1 g-COD/L d and Ymax = 0.27 L-CH4/g-CODremoved). These results suggest that UAF reactors are among the most effective reactor configurations for the anaerobic degradation of TA. PMID:24960022

Davutluoglu, Orkun I; Seckin, Galip

2014-01-01

62

In-reactor performance of pressure tubes in CANDU reactors  

NASA Astrophysics Data System (ADS)

The pressure tubes in CANDU reactors have been operating for times up to about 25 years. The in-reactor performance of Zr-2.5Nb pressure tubes has been evaluated by sampling and periodic inspection. This paper describes the behaviour and discusses the factors controlling the behaviour of these components in currently operating CANDU reactors. The mechanical properties (such as ultimate tensile strength, UTS, and fracture toughness), and delayed-hydride-cracking properties (crack growth rate Vc, and threshold stress intensity factor, KIH) change with irradiation; the former reach a limiting value at a fluence of <1 × 10 25 n m -2, while Vc and KIH reach a steady-state condition after a fluence of about 3 × 10 25 n m -2 and 3 × 10 24 n m -2, respectively. At saturation the UTS is raised by about 200 MPa, toughness is reduced to about 40% of its initial value, Vc increases by about a factor of ten while KIH is only slightly reduced. The role of microstructure and trace elements in these behaviours is described. Pressure tubes exhibit elongation and diametral expansion. The deformation behaviour is a function of operating conditions and material properties that vary from tube-to-tube and as a function of axial location. Semi-empirical predictive models have been developed to describe the deformation response of average tubes as a function of operating conditions. For corrosion and, more importantly deuterium pickup, semi-empirical predictive models have also been developed to represent the behaviour of an average tube. The effect of material variability on corrosion behaviour is less well defined compared with other properties. Improvements in manufacturing have increased fracture resistance by minimising trace elements, especially H and Cl, and reduced variability by tightening controls on forming parameters, especially hot-working temperatures.

Rodgers, D. K.; Coleman, C. E.; Griffiths, M.; Bickel, G. A.; Theaker, J. R.; Muir, I.; Bahurmuz, A. A.; Lawrence, S. St.; Resta Levi, M.

2008-12-01

63

Hydraulic characteristics and their effects on working performance of compartmentalized anaerobic reactor.  

PubMed

The compartmentalized anaerobic reactor (CAR) is a patent novel high-rate reactor and shows a great potential for its application. The hydraulic characteristics and their effects on the working performance of CAR were investigated. The flow pattern tended to plug flow at normal organic loading rate (OLR) and completely mixed flow at high OLRs. The relation of hydraulic dead space (HDS or V(h)) with hydraulic loading rate (HLR or L) and biogas production rate (BPR or G) was V(h) = 3.75 L + 0.19 G-9.47. The hydraulic efficiency of CAR was good or near to good. Both HLR and BPR had significant effects on the hydraulic efficiency, but their effect became less at super-high OLR. They also had a slight influence on the effective volume ratios of CAR, but the influence of BPR almost disappeared at super-high OLR. The good working performance of CAR was ascribed to the improved reactor configuration. PMID:22609654

Ji, Jun-yuan; Zheng, Kai; Xing, Ya-juan; Zheng, Ping

2012-07-01

64

Electricity from biogas  

SciTech Connect

Biogas is a medium-Btu methane and carbon dioxide mix produced by bacterial decomposition of organic matter. Its sources include landfills, waste water sludges, and animal wastes. It can fuel energy applications, of which electricity generation is a frequently-preferred option. The greatest current U.S. biogas recovery and energy use is at landfills, where biogas at about 80 landfill sites fuels a total of approximately 300 MWe. Wastewater treatment plants and confined animal waste management systems support additional electric power production. Generation of electricity from biogas can present difficulties due to the generally small scale of the generating facility, variable energy content of the gas, fluctuating availability, contaminant problems, and often-demanding control needs. However, such difficulties are being successfully addressed and economics for electricity generation are often favorable as biogas can be essentially {open_quotes}free{close_quotes} fuel. Biogas recovery and use has the additional advantage of mitigating a potent greenhouse gas. Biogas from U.S. landfills alone could fuel about 1% of U.S. electrical generation while giving climate change benefit equivalent to reducing CO{sub 2} emissions in the electricity sector by more than 10%. Growth in landfill gas use will be facilitated by recent regulations, advances in equipment, and improved management techniques such as {open_quotes}controlled landfilling{close_quotes}. The potential for biogas recovery and electricity production from sewage sludges, animal wastes and other organic resources such as agricultural residues is uncertain but probably exceeds the estimate for landfills.

Augenstein, D.; Benemann, J. [Institute for Environmental Management, Palo Alto, CA (United States); Hughes, E. [Electric Power Research Institute, Palo Alto, CA (United States)

1994-12-31

65

List of publications 1. Sun, L., Mller, B. and Schnrer, A. (2013) Biogas production from wheat straw community  

E-print Network

List of publications 1. Sun, L., Müller, B. and Schnürer, A. (2013) Biogas production from wheat biogas digesters. Biores. Technol. 132, 327­332 4. Manzoor, S., Müller, B., Niazi A., Bongcam-Rudloff E of syntrophic acetate- oxidising culture in biogas reactors exposed to increasing levels of ammonia. Applied

66

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

Microsoft Academic Search

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

R. Sowmeyan; G. Swaminathan

2008-01-01

67

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

68

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

69

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

70

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

71

A model to describe the performance of the UASB reactor.  

PubMed

A dynamic model to describe the performance of the Upflow Anaerobic Sludge Blanket (UASB) reactor was developed. It includes dispersion, advection, and reaction terms, as well as the resistances through which the substrate passes before its biotransformation. The UASB reactor is viewed as several continuous stirred tank reactors connected in series. The good agreement between experimental and simulated results shows that the model is able to predict the performance of the UASB reactor (i.e. substrate concentration, biomass concentration, granule size, and height of the sludge bed). PMID:23877239

Rodríguez-Gómez, Raúl; Renman, Gunno; Moreno, Luis; Liu, Longcheng

2014-04-01

72

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

73

The effects of digestion temperature and temperature shock on the biogas yields from the mesophilic anaerobic digestion of swine manure.  

PubMed

In order to obtain basic design criteria for anaerobic digesters of swine manure, the effects of different digesting temperatures, temperature shocks and feed loads, on the biogas yields and methane content were evaluated. The digester temperatures were set at 25, 30 and 35 degrees C, with four feed loads of 5%, 10%, 20% and 40% (feed volume/digester volume). At a temperature of 30 degrees C, the methane yield was reduced by only 3% compared to 35 degrees C, while a 17.4% reduction was observed when the digestion was performed at 25 degrees C. Ultimate methane yields of 327, 389 and 403 mL CH(4)/g VS(added) were obtained at 25, 30 and 35 degrees C, respectively; with moderate feed loads from 5% to 20% (V/V). From the elemental analysis of swine manure, the theoretical biogas and methane yields at standard temperature and pressure were 1.12L biogas/g VS(destroyed) and 0.724 L CH(4)/g VS(destroyed), respectively. Also, the methane content increased with increasing digestion temperatures, but only to a small degree. Temperature shocks from 35 to 30 degrees C and again from 30 to 32 degrees C led to a decrease in the biogas production rate, but it rapidly resumed the value of the control reactor. In addition, no lasting damage was observed for the digestion performance, once it had recovered. PMID:17306978

Chae, K J; Jang, Am; Yim, S K; Kim, In S

2008-01-01

74

A review on optimization production and upgrading biogas through CO2 removal using various techniques.  

PubMed

Biogas from anaerobic digestion of organic materials is a renewable energy resource that consists mainly of CH4 and CO2. Trace components that are often present in biogas are water vapor, hydrogen sulfide, siloxanes, hydrocarbons, ammonia, oxygen, carbon monoxide, and nitrogen. Considering the biogas is a clean and renewable form of energy that could well substitute the conventional source of energy (fossil fuels), the optimization of this type of energy becomes substantial. Various optimization techniques in biogas production process had been developed, including pretreatment, biotechnological approaches, co-digestion as well as the use of serial digester. For some application, the certain purity degree of biogas is needed. The presence of CO2 and other trace components in biogas could affect engine performance adversely. Reducing CO2 content will significantly upgrade the quality of biogas and enhancing the calorific value. Upgrading is generally performed in order to meet the standards for use as vehicle fuel or for injection in the natural gas grid. Different methods for biogas upgrading are used. They differ in functioning, the necessary quality conditions of the incoming gas, and the efficiency. Biogas can be purified from CO2 using pressure swing adsorption, membrane separation, physical or chemical CO2 absorption. This paper reviews the various techniques, which could be used to optimize the biogas production as well as to upgrade the biogas quality. PMID:24293277

Andriani, Dian; Wresta, Arini; Atmaja, Tinton Dwi; Saepudin, Aep

2014-02-01

75

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

PubMed

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 (15.7 L) were run at mesophilic conditions (30-35 degrees C) in a temperature-controlled environment with three hydraulic retention times (theta) of 15.7, 12 and 8.0 days. Imposed volumetric organic loading rates (L(V)) ranged from 0.65 to 4.257 kg COD/(m(3) day). The pH of the feed varied between 6.68 and 7.82. The hydraulic loading rates (L(H)) were controlled between 0.105 and 0.21 m(3)/(m(2)day). The daily biogas production rates ranged between 4.2 and 29.4 L/day. High volumetric COD removal rates (R(V)) ranging from 0.546 to 3.779 kg COD(removed)/(m(3)day) were achieved. On the basis of experimental results, two empirical models having a satisfactory correlation coefficient of about 0.9954 and 0.9416 were developed to predict daily biogas production (Q(g)) and effluent COD concentration (S(e)), respectively. Findings of this modeling study showed that optimal COD removals ranging from 86.3% to 90.6% were predicted with HRTs of 7.9, 9.5, 11.2, 12.6, 13.7 and 14.3 days, and L(V) of 1.27, 1.58, 1.78, 1.99, 2.20 and 2.45 kg COD/(m(3)day) for the corresponding influent substrate concentrations (S(i)) of 10,000, 15,000, 20,000, 25,000, 30,000 and 35,000 mg/L, respectively. PMID:17913349

Yetilmezsoy, Kaan; Sakar, Suleyman

2008-05-01

76

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

77

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

78

Production of Biogas from Wastewaters of Food Processing Industries  

E-print Network

in Holland. Operations on wastewater from the processing of sugar beets have shown hydraulic retention times of less than 10 hours with reactor loadings of at least 10 Kg COD per m3 digester volume per day and purification efficiencies exceeding 90%. Biogas...

Sax, R. I.; Holtz, M.; Pette, K. C.

1980-01-01

79

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

80

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

81

Use of biogas for cogeneration of heat and electricity for local application: performance evaluation of an engine power generator and a sludge thermal dryer.  

PubMed

A small unit of cogeneration of energy and heat was tested at the Centre for Research and Training on Sanitation UFMG/COPASA - CePTS, located at the Arrudas Sewage Treatment Plant, in Belo Horizonte, Minas Gerais, Brazil. The unit consisted of an engine power generator adapted to run on biogas, a thermal dryer prototype and other peripherals (compressor, biogas storage tank, air blower, etc.). The heat from engine power generator exhaust gases was directed towards the thermal dryer prototype to dry the sludge and disinfect it. The results showed that the experimental apparatus is self-sufficient in electricity, even producing a surplus, available for other uses. The tests of drying and disinfection of sludge lasted 7 h, leading to an increase in solids content from 4 to 8% (50% reduction in sludge volume). Although the drying of sludge was not possible (only thickening was achieved), the disinfection process proved very effective, enabling the complete inactivation of helminth eggs. PMID:23128634

Lobato, L C S; Chernicharo, C A L; Pujatti, F J P; Martins, O M; Melo, G C B; Recio, A A R

2013-01-01

82

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

83

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

84

Ecological analysis of a typical farm-scale biogas plant in China  

NASA Astrophysics Data System (ADS)

The aim of this work was to present the common anaerobic digestion technologies in a typical farm-scale biogas plant in China. The comprehensive benefits of most biogas plants in China have not been fully assessed in past decades due to the limited information of the anaerobic digestion processes in biogas plants. This paper analyzed four key aspects (i.e., operational performance, nonrenewable energy (NE) savings, CO2 emission reduction (CER) and economic benefits (EBs)) of a typical farm-scale biogas plant, where beef cattle manure was used as feedstock. Owing to the monitoring system, stable operation was achieved with a hydraulic retention time of 18-22 days and a production of 876,000 m3 of biogas and 37,960 t of digestate fertilizer annually. This could substantially substitute for the nonrenewable energy and chemical fertilizer. The total amount of NE savings and CER derived from biogas and digestate fertilizer was 2.10×107 MJ (equivalent to 749.7 tce) and 9.71×105 kg, respectively. The EBs of the biogas plant was 6.84×105 CNY·yr-1 with an outputs-to-inputs ratio of 2.37. As a result, the monitoring system was proved to contribute significantly to the sound management and quantitative assessment of the biogas plant. Biogas plants could produce biogas which could be used to substitute fossil fuels and reduce the emissions of greenhouse gases, and digestate fertilizer is also an important bio-product.

Duan, Na; Lin, Cong; Wang, Pingzhi; Meng, Jing; Chen, Hui; Li, Xue

2014-09-01

85

Residual biogas potential from the storage tanks of non-separated digestate and digested liquid fraction.  

PubMed

Biogas plants daily produce enormous volumes of digestate that can be handled in its raw form or after mechanical separation. In Italy, effluents are usually stored within aboveground, uncovered tanks, which make them potential emitters of biogas into the atmosphere. The purpose of this study was to estimate the amount of biogas emitted to the atmosphere during the storage phase of non-separated digestate and digested liquid fraction. The trials were performed at two northwest Italy 1 MWel. biogas plants. A floating system for the residual biogas recovery, and a set of three wind tunnels for NH3 emission measurement were used. The experiment demonstrated significant loss to the atmosphere for each of the gases; specifically, on average, 19.5 and 7.90 N m3 biogas MWhel.(-1) were emitted daily from the storage tanks of non-separated digestate and digested liquid fraction, respectively. PMID:21963905

Gioelli, F; Dinuccio, E; Balsari, P

2011-11-01

86

Ultrasound pretreatment for enhanced biogas production from olive mill wastewater.  

PubMed

This study investigates applicability of low frequency ultrasound technology to olive mill wastewaters (OMWs) as a pretreatment step prior to anaerobic batch reactors to improve biogas production and methane yield. OMWs originating from three phase processes are characterized with high organic content and complex nature. The treatment of the wastewater is problematic and alternative treatment options should be investigated. In the first part of the study, OMW samples were subjected to ultrasound at a frequency of 20kHz with applied powers varying between 50 and 100W under temperature controlled conditions for different time periods in order to determine the most effective sonication conditions. The level of organic matter solubilization at ultrasound experiments was assessed by calculating the ratio of soluble chemical oxygen demand/total chemical oxygen demand (SCOD/TCOD). The results revealed that the optimum ultrasonic condition for diluted OMW is 20kHz, 0.4W/mL for 10min. The application of ultrasound to OMW increased SCOD/TCOD ratio from 0.59 to 0.79. Statistical analysis (Friedman's tests) show that ultrasound was significantly effective on diluted OMW (p<0.05) in terms of SCOD parameter, but not for raw OMW (p>0.05). For raw OMW, this increase has been found to be limited due to high concentration of suspended solids (SS). In the second part of the study, biogas and methane production rates of anaerobic batch reactor fed with the ultrasound pretreated OMW samples were compared with the results of control reactor fed with untreated OMW in order to determine the effect of sonication. A nonparametric statistical procedure, Mann-Whitney U test, was used to compare biogas and methane production from anaerobic batch reactors for control and ultrasound pretreated samples. Results showed that application of low frequency ultrasound to OMW significantly improved both biogas and methane production in anaerobic batch reactor fed with the wastewater (p<0.05). Anaerobic batch reactor fed with ultrasound pretreated diluted OMW produced approximately 20% more biogas and methane compared with the untreated one (control reactor). The overall results indicated that low frequency ultrasound pretreatment increased soluble COD in OMW and subsequently biogas production. PMID:24880765

Oz, Nilgun Ayman; Uzun, Alev Cagla

2015-01-01

87

Microbial community structure and dynamics during co-digestion of whey permeate and cow manure in continuous stirred tank reactor systems.  

PubMed

Microbial community profiles in two parallel CSTR biogas reactors fed with whey permeate and cow manure were investigated. The operating conditions for these two reactors were identical, yet only one of them (R1) showed stable performance, whereas the other (R2) showed a decrease in methane production accompanied by accumulation of propionic acid and, later, acetic acid. This gave a unique opportunity to study the dynamics of the microbial communities in two biogas reactors apparently operating close to the edge of stability. The microbial community was dominated by Bacteroidetes and Firmicutes, and the methanogens Methanobacteriales and Methanomicrobiales in both reactors, but with larger fluctuations in R2. Correlation analyses showed that the depletion of propionic acid in R1 and the late increase of acetic acid in R2 was related to several bacterial groups. The biogas production in R1 shows that stable co-digestion of manure and whey can be achieved with reasonable yields. PMID:25222739

Hagen, Live Heldal; Vivekanand, Vivekanand; Linjordet, Roar; Pope, Phillip B; Eijsink, Vincent G H; Horn, Svein J

2014-11-01

88

Anaerobic degradation of coconut husk leachate using UASB-reactor.  

PubMed

Reffing of coconut husk, the majorprocess in quality coir fibre extraction, causes serious pollution with brackish water lagoons of Kerala. An attempt is made to treat the coconut husk leachate by using a laboratory scale UASB-reactor The experiment was conducted with loading of leachate from 1 kg of fresh coconut husk. The anaerobic treatment was done continuously The parameters like VFA, pH, COD and polyphenols were analysed regularly during the evaluation of the reactor performance. The polyphenol, VFA and COD were diminished gradually with time. The pH of the reactor during the study was found to be in the range of 6-8. The biogas production was increased with loading and about 82% of the total COD/kg husk could be converted to biogas. The maximum polyphenol loading in the reactor was reached to about 298.51 mg/l of husk. PMID:18380084

Neena, C; Ambily, P S; Jisha, M S

2007-07-01

89

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

90

Integrating chemical kinetics with CFD modeling for autothermal reforming of biogas  

Microsoft Academic Search

Using biogas for hydrogen production via autothermal reforming (ATR) can potentially increase the energy conversion efficiency and correspondingly reduce environmental impact. The present study aimed to investigate the performance and characteristics of biogas ATR. A two-dimensional numerical model was developed based on the integration of computational fluid dynamics (CFD) and chemical kinetics. The mass transport, chemical reactions and heat transfer

Jin Xuan; Michael K. H. Leung; Dennis Y. C. Leung; Meng Ni

2009-01-01

91

[Performance stability of CANON reactor and temperature impact].  

PubMed

In order to study long-term effect of completely autotrophic nitrogen removal over nitrite (CANON) reactor, performance stability was investigated by using synthetic inorganic ammonia-rich wastewater as raw water with a continuous flow CANON reactor. Both performances of short-cut nitrification and ANAMMOX were stable for more than one year. Under the condition that inner temperature at 35 degrees C +/- 1 degrees C, pH 7.39 and 8.01, and hydraulic retention time 3.7-5.1 h, the average total nitrogen removal load was 1.8 kg x (m3 x d)(-1), and the average and maximum total nitrogen removal efficiency were 65.09% and 81.65% respectively. Under sudden low temperature conditions, both ANAMMOX bacteria and AOB were inhibited, however, the ANAMMOX bacteria were inhibited more, which caused highly accumulated nitrite. When temperature increased to 35 degrees C as normal, the performance of CANON reactor recovered soon, which means low temperature impact will have no significant influence on stability. When the temperature reached more than 50 degrees C, the activity of ANAMMOX bacteria was completely destroyed, so high temperature must be avoided, though AOB can recovered to normal in one week. PMID:23233981

Fu, Kun-Ming; Zhang, Jie; Cao, Xiang-Sheng; Li, Dong; Meng, Xue-Zheng

2012-10-01

92

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

93

High Performance Fuel Desing for Next Generation Pressurized Water Reactors  

SciTech Connect

The use of internally and externally cooled annular fule rods for high power density Pressurized Water Reactors is assessed. The assessment included steady state and transient thermal conditions, neutronic and fuel management requirements, mechanical vibration issues, fuel performance issues, fuel fabrication methods and econmic assessment. The investigation was donducted by a team from MIT, Westinghouse, Gamma Engineering, Framatome ANP, and AECL. The analyses led to the conclusion that raising the power density by 50% may be possible with this advanced fuel. Even at the 150% power level, the fuel temperature would be a few hundred degrees lower than the current fuel temperatre. Significant economic and safety advantages can be obtained by using this fuel in new reactors. Switching to this type of fuel for existing reactors would yield safety advantages, but the economic return is dependent on the duration of plant shutdown to accommodate higher power production. The main feasiblity issue for the high power performance appears to be the potential for uneven splitting of heat flux between the inner and outer fuel surfaces due to premature closure of the outer fuel-cladding gap. This could be overcome by using a very narrow gap for the inner fuel surface and/or the spraying of a crushable zirconium oxide film at the fuel pellet outer surface. An alternative fuel manufacturing approach using vobropacking was also investigated but appears to yield lower than desirable fuel density.

Mujid S. Kazimi; Pavel Hejzlar

2006-01-31

94

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

95

Introduction to biogas production on the farm  

SciTech Connect

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 biogas; grantees' work and results have contributed to a growing body of information about practical applications of this technology. This publication was developed to share some of that information, to answer the basic questions about biogas production, and to lead farmers to more information. Section I introduces biogas and the various components of a biogas production system, discusses the system's benefits and liabilities, and provides a brief checklist to determine if biogas production may be applicable to an individual's particular situation. Section II features descriptions of four biogas projects of various sizes. Section III provides sources of additional information including descriptions of other biogas production projects.

Not Available

1984-03-01

96

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

97

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

98

Optimization of post-column reactor radius in capillary high performance liquid chromatography  

Microsoft Academic Search

A post-column reactor consisting of a simple open tube (Capillary Taylor Reactor) affects the performance of a capillary LC in two ways: stealing pressure from the column and adding band spreading. The former is a problem for very small radius reactors, while the latter shows itself for large reactor diameters. We derived an equation that defines the observed number of

Hongjuan Xu; Stephen G. Weber

2006-01-01

99

Wind effects on the performance of the reactor vessel auxiliary cooling system  

Microsoft Academic Search

One of the main safety features of current liquid-metal reactor (LMR) designs is the utilization of decay heat removal systems that remove heat by natural convection. The reactor vessel auxiliary cooling system (RVACS) is one of these passive systems. The performance of the reactor vessel auxiliary cooling system (RVACS) of a liquid-metal reactor is a function of the pressure difference

C. P. Tzanos; A. Hunsbedt

1996-01-01

100

Biogas recovery from a temperate climate covered anaerobic pond.  

PubMed

New Zealand has over 1000 anaerobic waste stabilisation ponds treating wastewater from farms and industry. Traditional anaerobic ponds were not designed to optimise anaerobic digestion to produce biogas and are therefore uncovered, releasing biogas to the atmosphere, which can cause odour problems and contributes to GHG emissions. The biogas production and treatment performance of an anaerobic piggery pond retrofitted with a perimeter cover working under field conditions was monitored over a 14 month period. The cover design proved successful in capturing biogas, mitigating odour and GHG issues and coping with New Zealand weather conditions. High solids removal rates (73% and 86% for TS and VS respectively) were achieved. An annual average biogas methane production rate of 0.263 m(3) CH(4)/kgVS(added) was observed, which is similar to gas production rates of mesophilic farm waste digesters, and indicates that the prolonged hydraulic and solids retention times of covered anaerobic ponds can fully compensate for lower operating temperatures. These results suggest that covered anaerobic ponds treating agricultural wastes in New Zealand have great potential to reduce odour and GHG emissions and recover renewable energy, while producing an easy to handle effluent for land irrigation or further treatment. PMID:20182082

Heubeck, S; Craggs, R J

2010-01-01

101

Environmental and economic analysis of application of water hyacinth for eutrophic water treatment coupled with biogas production.  

PubMed

The proliferation of water hyacinth is currently controlled by removing it from a water body and disposing it by landfill in China. Using water hyacinth to remove nutrients from water bodies and to produce biogas is another technically feasible option for the control of water hyacinth, but its environmental and economic performances are not well understood. This study collected data from an experimental biogas plant to develop a lifecycle analysis and a cost benefit analysis for the control of water hyacinth proliferation in a eutrophic lake in China. Comparison was made between the alternative option of using water hyacinth for biogas production and the current practice of disposing it in landfills. The results reveal that the biogas option is economically feasible with a positive energy balance. The removal of water hyacinth to produce biogas can contribute to water quality improvement and GHG emission reduction whose values, however, depend on the processing scale of the biogas plant. Since both the current approach and the biogas option can remove nutrients from water bodies, the additional value of water quality improvement resulting from the biogas option is only possible when the processing scale of the biogas plant is greater than the amount of water hyacinth disposed by landfill. The emission of methane deserves attention when water hyacinth is disposed by landfill. The biogas option can respond to China's policies on water pollution control, renewable energy development, and energy saving and emission reduction. PMID:22813757

Wang, Zanxin; Calderon, Margaret M

2012-11-15

102

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

103

Biogas production by encased bacteria in synthetic membranes: protective effects in toxic media and high loading rates.  

PubMed

A bioreactor including encased digesting bacteria for biogas production was developed, and its performance in toxic media and under high organic loading rates (OLRs) was examined and compared with traditional digestion reactors. The bacteria (3 g) were encased and sealed in 3 x 6 cm2 PVDF (polyvinylidene fluoride) membranes with a pore size of 0.1 microm, and then several sachets were placed in the reactors. They were then examined in toxic medium containing up to 3% limonene as a model inhibitor in batch reactors, and OLRs of up to 20 g COD/L.day in semi-continuous digestions. The free and encased cells with an identical total bacterial concentration of 9 g in a medium containing 2% limonene produced at most 6.56 and 23.06 mL biogas per day, respectively. In addition, the digestion with free cells completely failed at an OLR of 7.5 gCOD/L.day, while the encased cells were still fully active with a loading of 15 g COD/L x day. PMID:24350461

Youngsukkasem, Supansa; Akinbomi, Julius; Rakshit, Sudip K; Taherzadeh, Mohammad J

2013-01-01

104

Biogenic hydrogen conversion of de-oiled jatropha waste via anaerobic sequencing batch reactor operation: process performance, microbial insights, and CO2 reduction efficiency.  

PubMed

We report the semicontinuous, direct (anaerobic sequencing batch reactor operation) hydrogen fermentation of de-oiled jatropha waste (DJW). The effect of hydraulic retention time (HRT) was studied and results show that the stable and peak hydrogen production rate of 1.48 L/L ? d and hydrogen yield of 8.7 mL H2/g volatile solid added were attained when the reactor was operated at HRT 2 days (d) with a DJW concentration of 200 g/L, temperature 55 °C, and pH 6.5. Reduced HRT enhanced the production performance until 1.75 d. Further reduction has lowered the process efficiency in terms of biogas production and hydrogen gas content. The effluent from hydrogen fermentor was utilized for methane fermentation in batch reactors using pig slurry and cow dung as seed sources. The results revealed that pig slurry was a feasible seed source for methane generation. Peak methane production rate of 0.43 L CH4/L ? d and methane yield of 20.5 mL CH4/g COD were observed at substrate concentration of 10 g COD/L, temperature 30 °C, and pH 7.0. PCR-DGGE analysis revealed that combination of cellulolytic and fermentative bacteria were present in the hydrogen producing ASBR. PMID:24672398

Kumar, Gopalakrishnan; Lin, Chiu-Yue

2014-01-01

105

Anaerobic fermentation of biogas liquid pretreated maize straw by rumen microorganisms in vitro.  

PubMed

This study intended to investigate the effect of pretreatment of maize straw with biogas liquid on followed fermentation by rumen microorganisms in vitro. The multiple effects including treated time, temperature and dosage of biogas liquid in pretreatment on the followed fermentation performance were analyzed by orthogonal array. The optimum conditions of pretreatment were 9days, 25°C and 50% (v/w) dosage of biogas liquid, which were indicated by the corresponding crystallinity index, dry matter digestibility (DMD) and acetate limiting-step concentration were 57.5%, 73.76% and 1756mg/L, respectively. The ordering sequence of the influential factors for pretreatment was treated time > temperature > dosage of biogas liquid. The results of fermentation showed that the maize straw pretreated by biogas liquid was an efficient and economic pretreatment method of maize straw. PMID:24326083

Jin, Wenyao; Xu, Xiaochen; Gao, Yang; Yang, Fenglin; Wang, Gang

2014-02-01

106

Thermal analysis of a simple-cycle gas turbine in biogas power generation  

SciTech Connect

This paper investigates the technical feasibility of utilizing small simple-cycle gas turbines (25 kW to 125 kW) for biogas power generation through thermal analysis. A computer code, GTPower, was developed to evaluate the performance of small simple-cycle gas turbines specifically for biogas combustion. The 125 KW Solar Gas Turbine (Tital series) has been selected as the base case gas turbine for biogas combustion. After its design parameters and typical operating conditions were entered into GTPower for analysis, GTPower outputted expected values for the thermal efficiency and specific work. For a sensitivity analysis, the GTPower Model outputted the thermal efficiency and specific work. For a sensitivity analysis, the GTPower Model outputted the thermal efficiency and specific work profiles for various operating conditions encountered in biogas combustion. These results will assist future research projects in determining the type of combustion device most suitable for biogas power generation.

Yomogida, D.E. [California Energy Commission, Sacramento, CA (United States); Thinh, Ngo Dinh [California State Univ., Sacramento, CA (United States)

1995-09-01

107

The effect of microwave pretreatment on biogas production from agricultural straws.  

PubMed

Biogas production from microwave-pretreated agricultural residual straws that are used as feedstock was investigated in a laboratory batch study. Barley, spring wheat, winter wheat and oat straw were examined. To investigate the effect of changing the physicochemical structure of the straws on biogas production, the pretreatment processes were applied to two sample groups. The first group contained milled straw and the second group comprised milled wet straw that was prepared by the addition of deionized water. Both groups were subjected to microwave irradiation until oven temperatures of 200 or 300 °C were attained. Sixty-six identical batch anaerobic reactors were run under mesophilic conditions for 60 days. Preliminary test results showed that the microwave pretreatment of the different straws did not improve their anaerobic digestion. An increase in the treatment temperature led to lower biogas production levels. An inverse relationship between the thermal conversion yield and cumulative biogas production was observed. PMID:23201904

Sapci, Zehra

2013-01-01

108

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

109

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 2.8 g VS/L/day, independent of substrate mixture. The hydraulic retention was 25 days 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 (0.13-0.21 N L CH4/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

2013-12-01

110

ForPeerReview Microbiology and performance of a methanogenic biofilm reactor during the1  

E-print Network

ForPeerReview 1 Microbiology and performance of a methanogenic biofilm reactor during the1 start (present adress).7 Abbreviated running headline: Start-up of a methanogenic biofilm reactor8 Correspondence and performance of a methanogenic biofilm reactor during the start-up period. Journal of Applied Microbiology, vol

Paris-Sud XI, Université de

111

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

112

Assessment of innovative fuel designs for high performance light water reactors  

E-print Network

To increase the power density and maximum allowable fuel burnup in light water reactors, new fuel rod designs are investigated. Such fuel is desirable for improving the economic performance light water reactors loaded with ...

Carpenter, David Michael

2006-01-01

113

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

114

Biogas Production from Citrus Waste by Membrane Bioreactor  

PubMed Central

Rapid acidification and inhibition by d-limonene are major challenges of biogas production from citrus waste. As limonene is a hydrophobic chemical, this challenge was encountered using hydrophilic polyvinylidine difluoride (PVDF) membranes in a biogas reactor. The more sensitive methane-producing archaea were encapsulated in the membranes, while freely suspended digesting bacteria were present in the culture as well. In this membrane bioreactor (MBR), the free digesting bacteria digested the citrus wastes and produced soluble compounds, which could pass through the membrane and converted to biogas by the encapsulated cell. As a control experiment, similar digestions were carried out in bioreactors containing the identical amount of just free cells. The experiments were carried out in thermophilic conditions at 55 °C, and hydraulic retention time of 30 days. The organic loading rate (OLR) was started with 0.3 kg VS/m3/day and gradually increased to 3 kg VS/m3/day. The results show that at the highest OLR, MBR was successful to produce methane at 0.33 Nm3/kg VS, while the traditional free cell reactor reduced its methane production to 0.05 Nm3/kg VS. Approximately 73% of the theoretical methane yield was achieved using the membrane bioreactor. PMID:25167328

Wikandari, Rachma; Millati, Ria; Cahyanto, Muhammad Nur; Taherzadeh, Mohammad J.

2014-01-01

115

Temperature performance feedback for an intelligent reconfigurable reactor power controller  

Microsoft Academic Search

An experimental test bed for the development of power reactor intelligent control has been established and has already provided an evaluation of a robust optimal algorithm for improving reactor temperature response. The work described is developing a reactor demonstration of the fault-accommodating characteristics of a reconfigurable supervisory controller architecture, which was successfully demonstrated on a nuclear power plant feedwater system.

S. J. Kenney; M. A. Power; H. E. Garcia; R. M. Edwards

1994-01-01

116

Assessing UV reactor performance for treatment of finished water.  

PubMed

Recently, use of low levels of medium- and low-pressure ultraviolet light for successful inactivation of Cryptosporidium parvum oocysts has generated tremendous excitement in the water industry. Accurate delivery of the target dose, lamp performance, sensor stability and impact of water characteristics are some factors that could impact disinfection efficacy, in turn influencing decisions on application of this technology. To this end, American Water Systems, the largest investor owned water utility in the US, has responded to some of these challenges by ascertaining the long-term feasibility of applying UV for treatment of finished water. A 4 x 1 UV reactor with a 12 inch (0.3 m) diameter was installed after granular activated carbon filtration and was operated with a finished water flow rate of 600 gpm (2,700 L/min). Over a 12-month period, various chemical (THM, HAA, UV254, DOC, TOC, metals, nitrate, nitrites) and physical measurements (lamp voltage, current, sensor measurements) were monitored to define their impact (if any) on the operation of the reactor. MS2 bacteriophage challenge studies were conducted with various lamp configurations and lamp age. These inactivation data demonstrated high levels of correlation with controlled bench scale inactivation data. For C. parvum oocysts, bench scale studies were performed with a modified in vitro infectivity assay using HCT-8 cells, an enhanced infectivity protocol and with either immunofluorescence or quantitative PCR based detection. While both assays indicated increasing infections levels of HCT-8 cells with increasing oocyst inocula, UV treatment of oocysts produced markedly different infectivity responses. Based on the data generated in this study, one in vitro infectivity assay was selected to demonstrate > 3 logs inactivation with low UV doses (5 mJ/cm(20-10 mJ/cm2). PMID:12639026

Bukhari, Z; LeChevallier, M

2003-01-01

117

Microalgae conversion to biogas: thermal pretreatment contribution on net energy production.  

PubMed

Microalgal biomass harvested from wastewater treatment high rate algal ponds may be valorised through anaerobic digestion producing biogas. However, microalgae anaerobic biodegradability is limited by their complex cell wall structure. Thus, pretreatment techniques are being investigated to improve microalgae methane yield. In the current study, thermal pretreatment at relatively low temperatures of 75-95 °C was effective at enhancing microalgae anaerobic biodegradability; increasing the methane yield by 70% in respect to nonpretreated biomass. Microscopic images showed how the pretreatment damaged microalgae cells, enhancing subsequent anaerobic digestion. Indeed, digestate images showed how after pretreatment only species with resistant cell walls, such as diatoms, continued to be present. Energy balances based on lab-scale reactors performance at 20 days HRT, shifted from neutral to positive (energy gain around 2.7 GJ/d) after thermal pretreatment. In contrast with electricity consuming pretreatment methods, such as microwave irradiation, thermal pretreatment of microalgae seems to be scalable. PMID:24825469

Passos, Fabiana; Ferrer, Ivet

2014-06-17

118

Influence of the initial acidification step on biogas production and composition.  

PubMed

Laboratory-scale experiments were carried out to evaluate the effect of initial acidification of feedstock consisting of different components on biogas production and composition. Feedstock containing different agricultural wastes, biomass, and microorganisms was collected from five full-scale biogas plants. Two continuously stirred tank reactors were used. The fermentation temperature was 37 °C. The pH value was adjusted to 6.0 in the first reactor at the beginning of the experiment, and an initial pH value of 7.0 was implemented after 48 H. The second reactor was used as a control reactor with a constant pH of 7.0. The experiment lasted a total of 7 days. In the reactors, the gas phase was dominated by CH4 , CO2 , and N2 . The results showed that acidification increased biogas and carbon dioxide production in five cases, increased methane production and reduced nitrogen production in four cases, and reduced methane content in biogas in four of five cases. Only feedstock composed of 74% of different manures and 26% of plant material reduced the production of methane and increased the production of nitrogen after acidification. Other feedstock contained 47% to 96% plant material. An initial pH value of 6 could be recommended for mesophilic single-phase methanogenesis with a prevalence of plant material. PMID:24606319

Dirnena, Ilze; Dimanta, Ilze; Gruduls, Arturs; Kleperis, Janis; Elferts, Didzis; Nikolajeva, Vizma

2014-01-01

119

Parallelization and performance optimization of a dynamic PDE fixed bed reactor model for practical applications  

Microsoft Academic Search

An important inherent limitation of dynamic multiphase reactor flow simulations is the computational time requirements, making long time statistics intractable. A parallel CFD model has therefore been developed intended for the simulation of multi-phase reactors. The present version of the model simulates 2D reactive flows in a fixed bed reactor. The simulations are performed on two grids of different resolutions.

Håvard Lindborg; Vegard Eide; Steffen Unger; Siren T. Henriksen; Hugo A. Jakobsen

2004-01-01

120

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

121

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

122

Waste to Energy: Biogas CHP  

E-print Network

? Cogeneration Project Details ? Future Grease Digestion Project ? Questions and Answers 2 Southside Wastewater Treatment Plant 3 ? Located on over 2,800 acres, approximately 20 miles southeast of downtown Dallas ? Treatment capacity is 110 millions... Restaurant Waste Grease Trap Waste Methane Yield, ft3gas/per ton Brown Grease yields 4x the amount of gas as WWTP solids 17 165 660 ? Increase in biogas production, electricity and hot water ? Potential revenue from tipping fees ? Increased...

Wagner, R.

2011-01-01

123

Swine lagoon biogas utilization system  

SciTech Connect

A project was conceived to design and build a system to recover methane from pig manure with covered anaerobic lagoon technology. Covered lagoon technology lends itself both to new lagoon construction and to retrofit designs on existing anaerobic lagoons. A two cell passive in-ground digester/lagoon system was designed for a 600 sow feeder pig farm. The digester was covered with a flexible fabric cover made of 30 mil XR-5. The biogas has 1,100 ppm hydrogen sulfide. For the first month of operation 473 cubic feet of biogas per hour has been recovered from the digester 24 hours per day. At this gas flow the engine turns an induction generator to produce 17.1 KW per hour. A little over 80% of the farm`s electrical needs are generated with methane from swine manure. On an annual basis there will be 150,000 KWh of electricity produced from 4.3 million cubic feet of biogas.

Gettier, S.W.; Roberts, M. [Carroll`s Foods of Va., Inc., Waverly, VA (United States)

1994-12-31

124

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

125

A novel application of red mud-iron on granulation and treatment of palm oil mill effluent using upflow anaerobic sludge blanket reactor.  

PubMed

The performance of the upflow anaerobic sludge blanket reactor that used red mud-iron (RM-Fe) for methane production for the treatment of palm oil mill effluent (POME) at various hydraulic retention time (HRT) was determined. POME was used as the substrate carbon source. The biogas production rate was 1.7 l biogas/h with a methane yield of 0.78 l CH4/g CODremoved and chemical oxygen demand (COD) removal was 85% at POME concentration of 30 g COD/l at HRT 16 h. The reactor R2 showed average methane content of biogas and COD reduction of 78% and 85% at 400 mg/l RM-Fe. Significant increase in the granule diameter (up to 2900 ?m) in R2 was compared to control R1 (up to 86 ?m) at end of the experiment. PMID:25176306

Ahmad, Anwar

2014-01-01

126

High-performance simulations for atmospheric pressure plasma reactor  

NASA Astrophysics Data System (ADS)

Plasma-assisted processing and deposition of materials is an important component of modern industrial applications, with plasma reactors sharing 30% to 40% of manufacturing steps in microelectronics production. Development of new flexible electronics increases demands for efficient high-throughput deposition methods and roll-to-roll processing of materials. The current work represents an attempt of practical design and numerical modeling of a plasma enhanced chemical vapor deposition system. The system utilizes plasma at standard pressure and temperature to activate a chemical precursor for protective coatings. A specially designed linear plasma head, that consists of two parallel plates with electrodes placed in the parallel arrangement, is used to resolve clogging issues of currently available commercial plasma heads, as well as to increase the flow-rate of the processed chemicals and to enhance the uniformity of the deposition. A test system is build and discussed in this work. In order to improve operating conditions of the setup and quality of the deposited material, we perform numerical modeling of the plasma system. The theoretical and numerical models presented in this work comprehensively describe plasma generation, recombination, and advection in a channel of arbitrary geometry. Number density of plasma species, their energy content, electric field, and rate parameters are accurately calculated and analyzed in this work. Some interesting engineering outcomes are discussed with a connection to the proposed setup. The numerical model is implemented with the help of high-performance parallel technique and evaluated at a cluster for parallel calculations. A typical performance increase, calculation speed-up, parallel fraction of the code and overall efficiency of the parallel implementation are discussed in details.

Chugunov, Svyatoslav

127

Failed fuel pin performance in fast metal-cooled reactors  

Microsoft Academic Search

Experience with continued operation of failed mixed-oxide fuel pins in liquid-metal-cooled reactors or in-pile sodium loops is available from a variety of beyond-fuel-failure experiments. The phenomena and effects on a large reactor system of continued beyond-fuel-failure operation are not well understood, but, except for the release and deposition of fission products and the chemical reaction of sodium coolant to oxide

Plitz

1978-01-01

128

Advanced-power-reactor design concepts and performance characteristics  

NASA Technical Reports Server (NTRS)

Five reactor cooling concepts which allow continued reactor operation following a single rupture of the coolant system are presented for application with the APR. These concepts incorporate convective cooling, double containment, or heat pipes to ensure operation after a coolant line rupture. Based on an evaluation of several control system concepts, a molybdenum clad, beryllium oxide sliding reflector located outside the pressure vessel is recommended.

Davison, H. W.; Kirchgessner, T. A.; Springborn, R. H.; Yacobucci, H. G.

1974-01-01

129

Pilot-scale chemical-biological system for efficient H2S removal from biogas.  

PubMed

A pilot-scale chemical-biological process was performed efficiently to remove corrosive H2S from biogas. Consecutive 356-d livestock biogas purification was conducted at various H2S loading rates. The average inlet H2S concentration was 3542 ppm, and a removal efficiency of 95% was achieved with gas retention time of 288 s. This system showed robust performance during operation with stable parameters. Purified biogas with an average of 59% CH4 was collected for power production. Moreover, 28.3 kW h of power was produced by using a 30 kW biogas generator under 300 LPM biogas flow rate. During the 30-d shut down test, the jarosite formation resulted in pH decrease and appearance of Leptospirillum sp. and Sulfobacillus sp. in the bioreactor. However, the cell density of the inoculated Acidithiobacillus ferrooxidans was maintained above 5×10(7) CFU/g-AC during long-term operation. Thus, given the successful H2S elimination, the chemical-biological process is a feasible system for biogas purification. PMID:23186660

Lin, Wei-Chih; Chen, Yu-Pei; Tseng, Ching-Ping

2013-05-01

130

Increase of methane formation by ethanol addition during continuous fermentation of biogas sludge.  

PubMed

Very recently, it was shown that the addition of acetate or ethanol led to enhanced biogas formation rates during an observation period of 24 h. To determine if increased methane production rates due to ethanol addition can be maintained over longer time periods, continuous reactors filled with biogas sludge were developed which were fed with the same substrates as the full-scale reactor from which the sludge was derived. These reactors are well reflected conditions of a full-scale biogas plant during a period of 14 days. When the fermenters were pulsed with 50-100 mM ethanol, biomethanation increased by 50-150 %, depending on the composition of the biogas sludge. It was also possible to increase methane formation significantly when 10-20 mM pure ethanol or ethanolic solutions (e.g. beer) were added daily. In summary, the experiments revealed that "normal" methane production continued to take place, but ethanol led to production of additional methane. PMID:25344104

Refai, Sarah; Wassmann, Kati; van Helmont, Sebastian; Berger, Stefanie; Deppenmeier, Uwe

2014-12-01

131

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

132

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

133

biogas for rural communities TD390 Supervised learning: Study report  

E-print Network

0 biogas for rural communities TD390 Supervised learning: Study report Vaibhav Nasery Roll No. 08D highly successful rural biogas models wherein biogas is produced and utilized as a cooking fuel by the villagers. The two models studied are the Community Biogas plant established by SUMUL Dairy at Bhintbudrak

Sohoni, Milind

134

Sludge storage lagoon biogas recovery and use  

SciTech Connect

The City of Memphis has two wastewater treatment plants. The SWTP employs two large anaerobic digestion sludge lagoons as part of the overall sludge treatment system. Although these lagoons are effective in concentrating and digesting sludge, they can generate offensive odors. The SWTP uses aerobic digesters to partially stabilize the sludge and help reduce objectionable odors before it enters the lagoons. The anaerobic digestion of sludge in the lagoons results in the dispersion of a large quantity of biogas into the atmosphere. The City realized that if the lagoons could be covered, the odor problem could be resolved, and at the same, time, biogas could be recovered and utilized as a source of energy. In 1987, the City commissioned ADI International to conduct a feasibility study to evaluate alternative methods of covering the lagoons and recovering and utilizing the biogas. The study recommended that the project be developed in two phases: (1) recovery of the biogas and (2) utilization of the biogas. Phase 1 consists of covering the two lagoons with an insulated membrane to control odor and temperature and collect the biogas. Phase 1 was found to be economically feasible and offered a unique opportunity for the City to save substantial operating costs at the treatment facility. The Memphis biogas recovery project is the only application in the world where a membrane cover has been used on a municipal wastewater sludge lagoon. It is also the largest lagoon cover system in the world.

Muller, D.; Norville, C. (Memphis and Shelby County Div. of Planning and Development, TN (United States))

1991-07-01

135

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

136

Nitritation performance in membrane-aerated biofilm reactors differs from conventional biofilm systems  

Microsoft Academic Search

Nitrogen removal via nitrite has gained increasing attention in recent years due to its potential cost savings. Membrane-aerated biofilm reactors (MABRs) are one potential technology suitable to achieve nitritation. In this study we compared lab scale MABRs with conventional biofilm reactors to evaluate the influence of environmental conditions and operational parameters on nitritation performance. The oxygen mass transfer rate is

Susanne Lackner; Akihiko Terada; Harald Horn; Mogens Henze; Barth F. Smets

2010-01-01

137

Comparison of CFD, Biodosimetry and Lagrangian Actinometry to Assess UV Reactor Performance  

Microsoft Academic Search

Computational fluid dynamics (CFD) is becoming increasingly popular for assessing UV reactor performance. However, due to uncertainties in flow fields, lamp output and microbial response to UV, the CFD model needs to be validated by measurements. The combination of several experimental techniques with CFD modeling allows for a thorough understanding of the dominant processes occurring in UV reactors. Therefore, CFD

Bas A. Wols; C. H. M. Hofman-Caris; Danny J. H. Harmsen; Erwin F. Beerendonk; Johannis C. van Dijk; Po-Shun Chan; Ernest R. Blatchley III

2012-01-01

138

Space reactor fuels performance and development issues. [SP-100; 100 kW(e)  

SciTech Connect

Three compact reactor concepts are now under consideration by the US Space Nuclear Power Program (the SP-100 Program) as candidates for the first 100-kWe-class space reactor. Each of these reactor designs puts unique constraints and requirements on the fuels system, and raises issues of fuel systems feasibility and performance. This paper presents a brief overview of the fuel requirements for the proposed space reactor designs, a delineation of the technical feasibility issues that each raises, and a description of the fuel systems development and testing program that has been established to address key technical issues.

Wewerka, E.M.

1984-01-01

139

Performance and Safety Analysis of a Generic Small Modular Reactor  

E-print Network

renewable energy sources such as, wind and solar, along with their limitations on the areas of applicability and the energy output calls for a renaissance in nuclear energy. In this second nuclear era, deliberately small reactors are poised to play a major...

Kitcher, Evans Damenortey, 1987-

2012-11-07

140

Performance of metabolic pathway biomimetic reactors. I. Influence of hydrodynamics  

Microsoft Academic Search

Understanding and controlling the micro-environment in cell culture systems is essential to conduct intrinsic metabolic pathway studies. These are with either intact cellular or biomimetic systems. Novel reactor systems, as developed in our laboratory, couple membrane and electrode technologies that isolate key mechanistic steps. The biosynthesis of lactate from pyruvate was selected as a model system to demonstrate their capabilities.

R. J. Fisher; J. M. Fenton; X. Chen; J. Iranmahboob

2000-01-01

141

Full scale UASB reactor performance in the brewery industry.  

PubMed

In this paper the 7 year experience of the Oriental Breweries, located in Kumi, Korea utilizing a full-scale upflow anaerobic sludge blanket (UASB) reactor for the anaerobic pretreatment of brewery wastewater is presented. The anaerobic pretreatment system selected has successfully achieved the desired treatment efficiency for the brewery wastewater during that period and it has also continued operation even with low wastewater concentrations (average CODcr 1,400 mg l-1) and lower flow rates than specified by the design parameters. The CODcr removal of the UASB reactor averaged over 80% throughout the entire period, incurring normal running expenses of only $0.20-0.31 m-3 of treated water. In addition a further economical feature of the process was the utilization of the gas digester production as the municipal gas source, reducing total operating expenses around 30 to 45% and costing the plant only $0.1 m-3. Maintenance of good granule production, which is always a key issue in operating UASB systems, was not possible by this installation, however, so frequent expensive reseeding of the reactor was often necessary due to biomass washout. The full scale and lab scale research revealed that underloading can be as detrimental as overloading, due to excessively long retention time in the UASB system for the overall operating period and to excessive pre-acidification and/or incorrect reactor configuration of the completely mixed type. To enhance the sludge granulation, therefore, the installation of a pre-acidification reactor in the UASB system treating easily biodegradable substrates such as brewery wastewater is not necessary because adequate pre-acidification can occur in the equalization tank. PMID:11329809

Ahn, Y H; Min, K S; Speece, R E

2001-04-01

142

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

143

Thermal hydraulic performance analysis of a small integral pressurized water reactor core  

E-print Network

A thermal hydraulic analysis of the International Reactor Innovative and Secure (IRIS) core has been performed. Thermal margins for steady state and a selection of Loss Of Flow Accidents have been assessed using three ...

Blair, Stuart R. (Stuart Ryan), 1972-

2003-01-01

144

2008 Water Reactor Fuel Performance Meeting October 19~23, 2008, Renaissance Seoul Hotel, Seoul, Korea  

E-print Network

2008 Water Reactor Fuel Performance Meeting October 19~23, 2008, Renaissance Seoul Hotel, Seoul:michelle.flanagan@nrc.gov Abstract ­ The deformation behavior of Zr-based cladding forms a basis for fuel behavior codes and affects

Motta, Arthur T.

145

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

146

Bio-Gas Production from Alligator Weeds.  

National Technical Information Service (NTIS)

Laboratory experiments were conducted to study the effect of temperature, sample preparation, reducing agents, light intensity and pH of the media, on bio-gas and methane production from the microbial anaerobic decomposition of alligator weeds (Alternanth...

A. Latif

1976-01-01

147

Wastewater biogas recovery cuts energy costs  

SciTech Connect

The Northside Wastewater Treatment Plant in Durham, North Carolina is saving over $100,000 in costs due to biogas (methane) recovery and heat recovery. The plant processes 9.5 million gallons of waste water each day.

NONE

1994-08-01

148

Accident Performance of Light Water Reactor Cladding Materials  

SciTech Connect

During a loss of coolant accident as experienced at Fukushima, inadequate cooling of the reactor core forces component temperatures ever higher where they must withstand aggressive chemical environments. Conventional zirconium cladding alloys will readily oxidize in the presence of water vapor at elevated temperatures, rapidly degrading and likely failing. A cladding breach removes the critical barrier between actinides and fission products and the coolant, greatly increasing the probability of the release of radioactivity in the event of a containment failure. These factors have driven renewed international interest in both study and improvement of the materials used in commercial light water reactors. Characterization of a candidate cladding alloy or oxidation mitigation technique requires understanding of both the oxidation kinetics and hydrogen production as a function of temperature and atmosphere conditions. Researchers in the MST division supported by the DOE-NE Fuel Cycle Research and Development program are working to evaluate and quantify these parameters across a wide range of proposed cladding materials. The primary instrument employed is a simultaneous thermal analyzer (STA) equipped with a specialized water vapor furnace capable of maintaining temperatures above 1200 C in a range of atmospheres and water vapor contents. The STA utilizes thermogravimetric analysis and a coupled mass spectrometer to measure in situ oxidation and hydrogen production of candidate materials. This capability is unprecedented in study of materials under consideration for reactor cladding use, and is currently being expanded to investigate proposed coating techniques as well as the effect of coating defects on corrosion resistance.

Nelson, Andrew T. [Los Alamos National Laboratory

2012-07-24

149

The effect of velocity and porosity profiles on the performance of fixed bed reactors  

E-print Network

THE EFFECT OF VELOCITY AND POROSITY PROPILES ON THE PERFORMANCE OF FIXED B~M REACTORS A Thesis KAUSHIK AMIN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE December 1983 Major Subject: Chemical Engineering THE EFFECT OF VELOCITY AND POROSITY PROFILES ON THE PERFORMANCE OF FIXED BED REACTORS A Thesis by KAUSHIK AHIN Approved as to style and content by: R. G. Anthony (Chairman) Aydin german...

Amin, Kaushik

2012-06-07

150

Pretreatment of pulp mill secondary sludge for high-rate anaerobic conversion to biogas.  

PubMed

Three pretreatment methods were compared based on their ability to increase the extent and rate of anaerobic bioconversion of pulp mill secondary sludge to biogas. The pretreatment technologies used in these experiments were: (i) thermal pretreatment performed at 170 degrees C; (ii) thermochemical (caustic) pretreatment performed at pH 12 and 140 degrees C; and (iii) sonication performed at 20 kHz and 1 W mL(-1). Sludge samples were obtained from a sulfite and a kraft pulp mill, and biochemical methane potential (BMP) assays were performed using microbial granules obtained from a high-rate anaerobic digester operating at a pulp mill. Biogas production from untreated sludge was 0.05 mL mg(-1) of measured chemical oxygen demand (COD) and 0.20 mL mg(-1) COD for kraft and sulfite sludge, respectively. Thermal pretreatment had the highest impact on sludge biodegradability. In this case, biogas yield and production rate from sulfite sludge increased by 50% and 10 times, respectively, while biogas yield and production rate from kraft sludge increased by 280% and 300 times, respectively. Biogas yield correlated to soluble carbohydrate content better than soluble COD. PMID:19615891

Wood, Nicholas; Tran, Honghi; Master, Emma

2009-12-01

151

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

152

Co-digestion of sewage sludge with glycerol to boost biogas production  

SciTech Connect

The feasibility of adding crude glycerol from the biodiesel industry to the anaerobic digesters treating sewage sludge in wastewater treatment plants was studied in both batch and continuous experiments at 35 {sup o}C. Glycerol addition can boost biogas yields, if it does not exceed a limiting 1% (v/v) concentration in the feed. Any further increase of glycerol causes a high imbalance in the anaerobic digestion process. The reactor treating the sewage sludge produced 1106 {+-} 36 ml CH{sub 4}/d before the addition of glycerol and 2353 {+-} 94 ml CH{sub 4}/d after the addition of glycerol (1% v/v in the feed). The extra glycerol-COD added to the feed did not have a negative effect on reactor performance, but seemed to increase the active biomass (volatile solids) concentration in the system. Batch kinetic experiments showed that the maximum specific utilization rate ({mu}{sub max}) and the saturation constant (K{sub S}) of glycerol were 0.149 {+-} 0.015 h{sup -1} and 0.276 {+-} 0.095 g/l, respectively. Comparing the estimated values with the kinetics constants for propionate reported in the literature, it can be concluded that glycerol uptake is not the rate-limiting step during the process.

Fountoulakis, M.S., E-mail: mfountoul@steg.teiher.g [School of Agricultural Technology, Technological Educational Institute of Crete, Heraklion (Greece); Petousi, I.; Manios, T. [School of Agricultural Technology, Technological Educational Institute of Crete, Heraklion (Greece)

2010-10-15

153

Postgraduate Programme Renewable Energy (PPRE) --Biogas Workshop --01. -04. Feb. 2010 --Oldenburg University --venue: TGO, Marie-Curie-Strae 1, 26129 Oldenburg Programme Part 1  

E-print Network

-- Oldenburg University -- venue: TGO, Marie-Curie-StraÃ?e 1, 26129 Oldenburg Programme Part 1: Domestic Biogas 08:00 Arrival and Registration (of external guests) 08:45 Welcome (PPRE Staff Member) 09:00 Domestic:45 Biogas domestic appliances, design and performance (JL) 10:30 Coffee Break 10:45 Economic Aspects

Damm, Werner

154

Determination of the optimal rate for the microaerobic treatment of several H2S concentrations in biogas from sludge digesters.  

PubMed

The treatment of H2S in the biogas produced during anaerobic digestion has to be carried out to ensure the efficient long-lasting use of its energetic potential. The microaerobic removal of H2S was studied to determine the treatment capacity at low and high H2S concentrations in the biogas (0.33 and 3.38% v/v) and to determine the optimal O2 rate that achieved a concentration of H2S of 150 mg/Nm3 or lower. Research was performed in pilot-plant scale digesters of sewage sludge, with 200 L of working volume, in mesophilic conditions with a hydraulic retention time of 20 d. O2 was supplied at different rates to the headspace of the digester to create the microaerobic conditions. The treatment successfully removed H2S from the biogas with efficacies of 97% for the low concentration and 99% for the highest, in both cases achieving a concentration below 150 mg/Nm3. An optimal O2 rate of 6.4 NLO2/Nm3 of biogas when treating the biogas was found with 0.33% (v/v) of H2S and 118 NLO2/ Nm3 of biogas for the 3.38% (v/v) concentration. This relation may be employed to control the H2S content in the biogas while optimising the O2 supply. PMID:22053480

Díaz, I; Lopes, A C; Pérez, S I; Fdz-Polanco, M

2011-01-01

155

Effect of shock and mixed nitrophenolic loadings on the performance of UASB reactors  

Microsoft Academic Search

The effect of nitrophenolic shock loads on the performance of three bench-scale upflow anaerobic sludge blanket (UASB) reactors was studied using synthetic wastewater. Reactors R1, R2 and R3 were fed with 30mg\\/L concentration of 2-nitrophenol (2-NP), 4-nitrophenol (4-NP) and 2,4-dinitrophenol (2,4-DNP), respectively, along with methanol (COD=2000mg\\/L), sodium nitrate (NO3?-N=200mg\\/L), and other nutrients. The reactors were in continuous operation for more

Khursheed Karim; S. K. Gupta

2006-01-01

156

Influence of anaerobic co-digestion of sewage and brewery sludges on biogas production and sludge quality  

Microsoft Academic Search

This research investigated operating parameters and treatment efficiency for the digestion of sewage and brewery sludge. The prime objective of this study was to enhance the quality of treated sludge for use as agriculture fertilizer and to enhance biogas production, a by-product that can be used as an energy source. Three bench-scale completely stirred tank reactor (CSTR) anaerobic digesters were

Athapol Pecharaply; Preeda Parkpian; Ajit P. Annachhatre; Aroon Jugsujinda

2007-01-01

157

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

158

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

159

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

160

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

161

Biogas electricity -- The Pura village case study  

SciTech Connect

A potentially useful decentralized source of energy is biogas, which is an approximately 60:40 mixture of methane (CH{sub 4}) and carbon dioxide (CO{sub 2}), produced by the anaerobic fermentation of cellulosic biomass materials such as bovine wastes. Since 1987, the traditional system of obtaining water, illumination, and fertilizer in Pura village in south India has been replaced with a community biogas plant electricity-generation system. The technical, managerial, and economical aspects of this system are the subject manner of the present paper. Various subsystems are described, and the problems of operation and maintenance under field conditions are also discussed. A comparison of Pura`s present community biogas system with its traditional means for obtaining water, illumination, and fertilizer shows that the households are winners on all counts, having obtained such benefits as improved hygiene and convenience at relatively low cost. The Pura community biogas plant is held together and sustained by the convergence of individual and collective interests. Noncooperation with the community biogas plant results in a heavy individual price (access to water and light being cut off by the village), which is too great a personal loss to compensate for the minor advantages of noncooperation and noncontribution to collective interests.

Rajabapaiah, P.; Jayakumar, S. [Indian Inst. of Science, Bangalore (India); Reddy, A.K.N. [International Energy Initiative, Bangalore (India)

1993-12-31

162

Performance Potential of the Colloid Core Reactor Concept in Near-Earth Applications  

Microsoft Academic Search

An Air Force research program has produced performance estimates for the ; colloid core nuclear reactor rocket engine concept. These values are ; parametrically varied to determine their individual influence on an advanced ; nuclear upper stage to the Space Transportation System. Pessimistic and ; optimistic performance of the concept is estimated. The concept is compared with ; other propulsion

Capt. Thomas C. Meier

1973-01-01

163

Performance Characteristics of a High-Temperature Servomechanism for Reactor Control Rods  

Microsoft Academic Search

Feasibility of servo operation, with supply gas and average part temperatures over 1000°F, for periods over two hours is well established. Performance required for vernier rod control in the Tory II-C reactor was nearly achieved with the first prototype design. Analytical study revealed characteristics of the pneumatic valve and motor significant in designing performance into systems of this type, and

R. B. Hollstien; M. J. Nutter; C. D. Stout

1962-01-01

164

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

2010-10-01

165

Rapid and high yield biogas production from Jatropha seed cake by co-digestion with bagasse and addition of Fe2+.  

PubMed

Co-digestion and metal ion addition strategies to improve the biogas production potential of Jatropha seed cake (JSC) by anaerobic digestion were evaluated in the present study. Initially, batch experiments were carried out to obtain the maximum JSC concentration for optimum biogas yield, followed by co-digestion with bagasse, and addition of Fe2+. The optimum JSC concentration of 15% (w/v) gave biogas production rate (BPR) of 66.4 mL/d, specific BPR of 9.7 mL/d/gVS and biogas yield of 0.064 m3/kgVS. The co-digestion strategy increased the carbon/nitrogen of feed (10% JSC + 5% Bagasse, w/v) to 26.5 from 14 (JSC alone), resulting in biogas yield of 0.136 m3/kgVS of JSC, a 2.1-fold increase. Addition of Fe2+ to JSC and bagasse mixture led to biogas yield of 0.203 m3/kgVS, with methane content of 66% and methane production of 8.8 L/L reactor. With short digestion time of 15 days, co-digestion of JSC with bagasse and addition of Fe2+ showed 3.2-fold higher biogas yield than JSC alone. PMID:24617057

Sen, Kalyani; Mahalingam, Shanthi; Sen, Biswarup

2013-01-01

166

5. oktober 2009 Precision control of biogas plants  

E-print Network

5. oktober 2009 Precision control of biogas plants Final report Henrik B. Møller, Anders M. Nielsen: "Precision control of biogas plants", J. Nr. 33031-0028, funded by EUDP 2005. The final report consists. Danish summary of the results: Det har været formålet at udvikle drift og design af biogas anlæg med

167

Choosing co-substrates to supplement biogas production from animal slurry - A life cycle assessment of the environmental consequences.  

PubMed

Biogas production from animal slurry can provide substantial contributions to reach renewable energy targets, yet due to the low methane potential of slurry, biogas plants depend on the addition of co-substrates to make operations profitable. The environmental performance of three underexploited co-substrates, straw, organic household waste and the solid fraction of separated slurry, were assessed against slurry management without biogas production, using LCA methodology. The analysis showed straw, which would have been left on arable fields, to be an environmentally superior co-substrate. Due to its low nutrient content and high methane potential, straw yields the lowest impacts for eutrophication and the highest climate change and fossil depletion savings. Co-substrates diverted from incineration to biogas production had fewer environmental benefits, due to the loss of energy production, which is then produced from conventional fossil fuels. The scenarios can often provide benefits for one impact category while causing impacts in another. PMID:25226057

Croxatto Vega, Giovanna Catalina; Ten Hoeve, Marieke; Birkved, Morten; Sommer, Sven G; Bruun, Sander

2014-11-01

168

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

169

Reviewing real-time performance of nuclear reactor safety systems  

SciTech Connect

The purpose of this paper is to recommend regulatory guidance for reviewers examining real-time performance of computer-based safety systems used in nuclear power plants. Three areas of guidance are covered in this report. The first area covers how to determine if, when, and what prototypes should be required of developers to make a convincing demonstration that specific problems have been solved or that performance goals have been met. The second area has recommendations for timing analyses that will prove that the real-time system will meet its safety-imposed deadlines. The third area has description of means for assessing expected or actual real-time performance before, during, and after development is completed. To ensure that the delivered real-time software product meets performance goals, the paper recommends certain types of code-execution and communications scheduling. Technical background is provided in the appendix on methods of timing analysis, scheduling real-time computations, prototyping, real-time software development approaches, modeling and measurement, and real-time operating systems.

Preckshot, G.G. [Lawrence Livermore National Lab., CA (United States)

1993-08-01

170

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

171

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

172

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

173

The good, the bad or the ugly: Microbial biomass of biogas residues as a contributor to soil carbon cycle  

NASA Astrophysics Data System (ADS)

Loss of soil organic matter is a recent problem in soils all over the world. This can be related to enhanced mineralization of the soil organic matter due to land use change, which is a source of anthropogenic carbon dioxide increase. For example, the carbon input from plant residues is reduced because of the increased cultivation of bioenergy crops. In order to avoid soil degradation, application of biogas residues is a common practice in such areas. Biogas residues are side products of biogas production and contain microbial biomass. Application of these residues as soil additive influences the soil microorganisms as well as the carbon cycle. We study this effect by incubating 13C-labeled biogas residues in an arable soil from the Static Fertilization Experiment in Bad Lauchstaedt, Germany. Labeled residues were produced via labeling of active microbial biomass by addition of KH13CO3 to biogas reactors. High enrichment in the various phospholipid fatty acids proved the successful labeling of the biomass. The labeled biogas residues are being long-term incubated in the soil. During incubation, we monitor the fate of the carbon by analyzing the label in phospholipid fatty acids, amino acids as well as carbon dioxide. This allows us to trace the fate of the biogas residues-derived C in soil and to quantify the effect on the transformation of the natural soil organic matter (e.g. negative effects such as priming effects). Also, microbial community dynamics will be determined using molecular biology tools such as denaturing gradient gel electrophoresis (DGGE) and real-time quantitative PCR (Q-PCR). In order to prevent potentially negative effects, various additives such as charred biomaterials, clays and chopped bark will be tested to improve the carbon storage in soil. In conclusion, this study investigates the fate and impact of biogas residues used as a soil additive on the soil microbial community and amount of soil organic matter. It is aimed to understand and clarify whether the biogas residues play the good, the bad or just the ugly in soil carbon cycling. Thus, recommendations about the use of biogas residues as fertilizers or soil additives in agriculture will be contributed. Furthermore, the data will be a potential input to a landscape generator model which will predict soil quality development in Central Germany.

Coban, H.; Miltner, A.; Kaestner, M.

2013-12-01

174

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

175

Comparative analysis of environmental impacts of maize-biogas and photovoltaics on a land use basis  

SciTech Connect

This study aims to stimulate the discussion on how to optimize a sustainable energy mix from an environmental perspective and how to apply existing renewable energy sources in the most efficient way. Ground-mounted photovoltaics (PV) and the maize-biogas-electricity route are compared with regard to their potential to mitigate environmental pressure, assuming that a given agricultural area is available for energy production. Existing life cycle assessment (LCA) studies are taken as a basis to analyse environmental impacts of those technologies in relation to conventional technology for power and heat generation. The life-cycle-wide mitigation potential per area used is calculated for the impact categories non-renewable energy input, green house gas (GHG) emissions, acidification and eutrophication. The environmental performance of each system depends on the scenario that is assumed for end energy use (electricity and heat supply have been contemplated). In all scenarios under consideration, PV turns out to be superior to biogas in almost all studied impact categories. Even when maize is used for electricity production in connection with very efficient heat usage, and reduced PV performance is assumed to account for intermittence, PV can still mitigate about four times the amount of green house gas emissions and non-renewable energy input compared to maize-biogas. Soil erosion, which can be entirely avoided with PV, exceeds soil renewal rates roughly 20-fold on maize fields. Regarding the overall Eco-indicator 99 (H) score under most favourable assumptions for the maize-biogas route, PV has still a more than 100% higher potential to mitigate environmental burden. At present, the key advantages of biogas are its price and its availability without intermittence. In the long run, and with respect to more efficient land use, biogas might preferably be produced from organic waste or manure, whereas PV should be integrated into buildings and infrastructures. (author)

Graebig, Markus; Fenner, Richard [Centre for Sustainable Development, Department of Engineering, University of Cambridge (United Kingdom); Bringezu, Stefan [Wuppertal Institute for Climate, Environment and Energy. P.B. 100480, 42004 Wuppertal (Germany)

2010-07-15

176

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

2012-06-01

177

The effect of catalyst length and downstream reactor distance on catalytic combustor performance  

NASA Technical Reports Server (NTRS)

A study was made to determine the effects on catalytic combustor performance which resulted from independently varying the length of a catalytic reactor and the length available for gas-phase reactions downstream of the catalyst. Monolithic combustion catalysts from three manufacturers were tested in a combustion test rig with no. 2 diesel fuel. Catalytic reactor lengths of 2.5 and 5.4 cm, and downstream gas-phase reaction distances of 7.3, 12.4, 17.5, and 22.5 cm were evaluated. Measurements of carbon monoxide, unburned hydrocarbons, nitrogen oxides, and pressure drop were made. The catalytic-reactor pressure drop was less than 1 percent of the upstream total pressure for all test configurations and test conditions. Nitrogen oxides and unburned hydrocarbons emissions were less than 0.25 g NO2/kg fuel and 0.6 g HC/kg fuel, respectively. The minimum operating temperature (defined as the adiabatic combustion temperature required to obtain carbon monoxide emissions below a reference level of 13.6 g CO/kg fuel) ranged from 1230 K to 1500 K for the various conditions and configurations tested. The minimum operating temperature decreased with increasing total (catalytic-reactor-plus-downstream-gas-phase-reactor-zone) residence time but was independent of the relative times spent in each region when the catalytic-reactor residence time was greater than or equal to 1.4 ms.

Anderson, D.

1980-01-01

178

Safety System Design Concept and Performance Evaluation for a Long Operating Cycle Simplified Boiling Water Reactor  

SciTech Connect

The long operating cycle simplified boiling water reactor is a reactor concept that pursues both safety and the economy by employing a natural circulation reactor core without a refueling, a passive decay heat removal, and an integrated building for the reactor and turbine. Throughout the entire spectrum of the design basis accident, the reactor core is kept covered by the passive emergency core cooling system. The decay heat is removed by the conventional active low-pressure residual heat removal system. As for a postulated severe accident, the suppression pool water floods the lower part of the reactor pressure vessel (RPV) in the case when core damage occurs, and the in-vessel retention that keeps the melt inside the RPV is achieved by supplying the coolant. The containment adopts a parallel-double-steel-plate structure similar to a hull structure, which contains coolant between the inner and outer walls to absorb the heat transferred from the inside of the containment. Consequently, the containment structure functions as a passive containment cooling system (PCCS) to remove the decay heat in case of an accident. This paper describes the PCCS performance evaluation by using TRAC code to show one of the characteristic plant features. The core damage frequency for internal events was also evaluated to examine the safety level of the plant and to show the adequacy of the safety system design.

Arai, Kenji; Suzuki, Seijiro; Nakamaru, Mikihide; Heki, Hideaki [Toshiba Corporation (Japan)

2003-07-15

179

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

180

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

181

Media Factors Affecting the Performance of Upflow Anaerobic Packed-Bed Reactors  

Microsoft Academic Search

Numerous studies have demonstrated that anaerobic packed-bed reactors (APBRs) containing media such as clay chip, small stone, and porous plastic modules are effective for treating a variety of organic wastes. Most of these studies focused on the treatment capabilities of the processes, yet little work was done about the factors affecting their designs and performance. This paper presents the results

Tay Joo-Hwa; Show Kuan-Yeow; S. Jeyaseelan

1997-01-01

182

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

183

Assessing the influence of reactor system design criteria on the performance of model colon fermentation units.  

PubMed

Fermentation reactor systems are a key platform in studying intestinal microflora, specifically with respect to questions surrounding the effects of diet. In this study, we develop computational representations of colon fermentation reactor systems as a way to assess the influence of three design elements (number of reactors, emptying mechanism, and inclusion of microbial immobilization) on three performance measures (total biomass density, biomass composition, and fibre digestion efficiency) using a fractional-factorial experimental design. It was determined that the choice of emptying mechanism showed no effect on any of the performance measures. Additionally, it was determined that none of the design criteria had any measurable effect on reactor performance with respect to biomass composition. It is recommended that model fermentation systems used in the experimenting of dietary effects on intestinal biomass composition be streamlined to only include necessary system design complexities, as the measured performance is not benefited by the addition of microbial immobilization mechanisms or semi-continuous emptying scheme. Additionally, the added complexities significantly increase computational time during simulation experiments. It was also noted that the same factorial experiment could be directly adapted using in vitro colon fermentation systems. PMID:24216456

Moorthy, Arun S; Eberl, Hermann J

2014-04-01

184

Modeling of the performance of weapons MOX fuel in light water reactors  

SciTech Connect

Both the Russian Federation and the US are pursing mixed uranium-plutonium oxide (MOX) fuel in light water reactors (LWRs) for the disposition of excess plutonium from disassembled nuclear warheads. Fuel performance models are used which describe the behavior of MOX fuel during irradiation under typical power reactor conditions. The objective of this project is to perform the analysis of the thermal, mechanical, and chemical behavior of weapons MOX fuel pins under LWR conditions. If fuel performance analysis indicates potential questions, it then becomes imperative to assess the fuel pin design and the proposed operating strategies to reduce the probability of clad failure and the associated release of radioactive fission products into the primary coolant system. Applying the updated code to anticipated fuel and reactor designs, which would be used for weapons MOX fuel in the US, and analyzing the performance of the WWER-100 fuel for Russian weapons plutonium disposition are addressed in this report. The COMETHE code was found to do an excellent job in predicting fuel central temperatures. Also, despite minor predicted differences in thermo-mechanical behavior of MOX and UO{sub 2} fuels, the preliminary estimate indicated that, during normal reactor operations, these deviations remained within limits foreseen by fuel pin design.

Alvis, J.; Bellanger, P.; Medvedev, P.G.; Peddicord, K.L. [Texas A and M Univ., College Station, TX (United States). Nuclear Engineering Dept.; Gellene, G.I. [Texas Tech Univ., Lubbock, TX (United States). Dept. of Chemistry and Biochemistry

1999-05-01

185

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

186

Simulation of the Performance of a Fundamental Neutron Physics Beamline at the High Flux Isotope Reactor  

Microsoft Academic Search

We study the expected performance of the proposed fundamental neutron physics beamline at the upgraded High Flux Isotope Reactor at Oak Ridge National Laboratory. A curved neutron guide transmits the neutrons from the new cold source into a guide hall. A novel feature of the proposed guide is the use of vertical focusing to increase the flux for experiments that

R. Mahurin; Geoffrey L Greene; Paul Edward Koehler; Vince Cianciolo

2005-01-01

187

Bio-gas production from alligator weeds  

NASA Technical Reports Server (NTRS)

Laboratory experiments were conducted to study the effect of temperature, sample preparation, reducing agents, light intensity and pH of the media, on bio-gas and methane production from the microbial anaerobic decomposition of alligator weeds (Alternanthera philoxeroides. Efforts were also made for the isolation and characterization of the methanogenic bacteria.

Latif, A.

1976-01-01

188

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

189

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

190

Energy Economics of Farm Biogas in Cold Climates  

SciTech Connect

Anaerobic digestion of farm and dairy waste has been shown to be capital intensive. One way to improve digester economics is to co-digest high-energy substrates together with the dairy manure. Cheese whey for example represents a high-energy substrate that is generated during cheese manufacture. There are currently no quantitative tools available that predict performance of co-digestion farm systems. The goal of this project was to develop a mathematical tool that would (1) predict the impact of co-digestion and (2) determine the best use of the generated biogas for a cheese manufacturing plant. Two models were developed that separately could be used to meet both goals of the project. Given current pricing structures of the most economical use of the generated biogas at the cheese manufacturing plant was as a replacement of fuel oil to generate heat. The developed digester model accurately predicted the performance of 26 farm digesters operating in the North Eastern U.S.

Pragasen Pillay; Stefan Grimberg; Susan E. Powers

2012-10-24

191

Thermal performance of a packed bed reactor for a high-temperature chemical heat pump  

Microsoft Academic Search

SUMMARY The thermal performance of a chemical heat pump that uses the reaction system of calcium oxide\\/lead oxide\\/carbon dioxide, which is developed for utilization of high-temperature heat above 8003C, is studied experimentally. The thermal performance of a packed-bed reactor of a calcium oxide\\/carbon dioxide reac- tion system, which stores and transforms a high-temperature heat source in the heat pump operation,

Yukitaka Kato; Tadashi O-shim; Yoshio Yoshizawa

2001-01-01

192

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. PMID:23607263

2013-01-01

193

Analysis of bacterial communities and bacterial pathogens in a biogas plant by the combination of ethidium monoazide, PCR and Ion Torrent sequencing.  

PubMed

The present study investigated the changes of bacterial community composition including bacterial pathogens along a biogas plant, i.e. from the influent, to the biogas reactor and to the post-digester. The effects of post-digestion temperature and time on the changes of bacterial community composition and bacterial pathogens were also studied. Microbial analysis was made by Ion Torrent sequencing of the PCR amplicons from ethidium monoazide treated samples, and ethidium monoazide was used to cleave DNA from dead cells and exclude it from PCR amplification. Both similarity and taxonomic analysis showed that the bacterial community composition in the influent was changed after anaerobic digestion. Firmicutes were dominant in all the samples, while Proteobacteria decreased in the biogas reactor compared with the influent. Variations of bacterial community composition in the biogas reactor with time were also observed. This could be attributed to varying composition of the influent. Batch experiments showed that the methane recovery from the digested residues (obtained from biogas reactor) was mainly related with post-digestion temperature. However, post-digestion time rather than temperature had a significant effect on the changes of bacterial community composition. The changes of bacterial community composition were also reflected in the changes of relative abundance of bacterial pathogens. The richness and relative abundance of bacterial pathogens were reduced after anaerobic digestion in the biogas reactor. It was found in batch experiments that bacterial pathogens showed the highest relative abundance and richness after 30 days' post-digestion. Streptococcus bovis was found in all the samples. Our results showed that special attention should be paid to the post-digestion since the increase in relative abundance of bacterial pathogens after post-digestion might reflect regrowth of bacterial pathogens and limit biosolids disposal vectors. PMID:24852413

Luo, Gang; Angelidaki, Irini

2014-09-01

194

Benchmarking of the MIT High Temperature Gas-Cooled Reactor TRISO-Coated Particle Fuel Performance Model  

E-print Network

Benchmarking of the MIT High Temperature Gas-Cooled Reactor TRISO-Coated Particle Fuel Performance on Graduate Students #12;#12;Benchmarking of the MIT High Temperature Gas-Cooled Reactor TRISO-Coated Particle has developed a Coated Particle Fuel Performance Model to study the behavior of TRISO nuclear fuels

195

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

196

Performance evaluation of a continuous flow photocatalytic reactor for wastewater treatment.  

PubMed

A novel photocatalytic reactor for wastewater treatment was designed and constructed. The main part of the reactor was an aluminum tube in which 12 stainless steel circular baffles and four quartz tube were placed inside of the reactor like shell and tube heat exchangers. Four UV-C lamps were housed within the space of the quartz tubes. Surface of the baffles was coated with TiO2. A simple method was employed for TiO2 immobilization, while the characterization of the supported photocatalyst was based on the results obtained through performing some common analytical methods such as X-ray diffraction (XRD), scanning electron microscope (SEM), and BET. Phenol was selected as a model pollutant. A solution of a known initial concentration (20, 60, and 100 ppmv) was introduced to the reactor. The reactor also has a recycle flow to make turbulent flow inside of the reactor. The selected recycle flow rate was 7?×?10(-5) m(3).s(-1), while the flow rate of feed was 2.53?×?10(-7), 7.56?×?10(-7), and 1.26?×?10(-6) m(3).s(-1), respectively. To evaluate performance of the reactor, response surface methodology was employed. A four-factor three-level Box-Behnken design was developed to evaluate the reactor performance for degradation of phenol. Effects of phenol inlet concentration (20-100 ppmv), pH (3-9), liquid flow rate (2.53?×?10(-7)-1.26?×?10(-6) m(3).s(-1)), and TiO2 loading (8.8-17.6 g.m(-2)) were analyzed with this method. The adjusted R (2) value (0.9936) was in close agreement with that of corresponding R (2) value (0.9961). The maximum predicted degradation of phenol was 75.50 % at the optimum processing conditions (initial phenol concentration of 20 ppmv, pH???6.41, and flow rate of 2.53?×?10(-7) m(3).s(-1) and catalyst loading of 17.6 g.m(-2)). Experimental degradation of phenol determined at the optimum conditions was 73.7 %. XRD patterns and SEM images at the optimum conditions revealed that crystal size is approximately 25 nm and TiO2 nanoparticles with visible agglomerates distribute densely and uniformly over the surface of stainless steel substrate. BET specific surface area of immobilized TiO2 was 47.2 and 45.8 m(2) g(-1) before and after the experiments, respectively. Reduction in TOC content, after steady state condition, showed that maximum phenol decomposition occurred at neutral condition (pH???6). PMID:24946704

Rezaei, Mohammad; Rashidi, Fariborz; Royaee, Sayed Javid; Jafarikojour, Morteza

2014-11-01

197

pH regulation of alkaline wastewater with carbon dioxide: a case study of treatment of brewery wastewater in UASB reactor coupled with absorber.  

PubMed

Studies were carried out with carbon dioxide absorber (CA) to evaluate the usage of carbon dioxide (CO(2)) in the biogas as an acidifying agent by Up-flow Anaerobic Sludge Blanket (UASB) reactor. Investigation on the 5l absorber revealed that ratio of brewery wastewater (BW) flow rate to biogas flow rate of 4.6-5.2 was optimum for minimum consumption of CO(2) for acidification. The acidified BW after the absorber was treated in UASB reactor with optimum organic loading rate (OLR) of 23.1 kg COD/m(3)/day and hydraulic retention time (HRT) of 2h. UASB reactor exhibited good performance with respect to reduction of chemical oxygen demand (COD) and methane yield. The implications of the present study on the full scale anaerobic reactor of medium scale brewery revealed that sufficient cost savings could be made if CO(2) in the biogas or CO(2) that was being wasted (let out to the atmosphere) can be used instead of sulfuric acid (H(2)SO(4)) for pH control. PMID:17046245

Rao, A Gangagni; Reddy, T Sasi Kanth; Prakash, S Surya; Vanajakshi, J; Joseph, Johny; Sarma, P N

2007-08-01

198

Improvement of Membrane Performances to Enhance the Yield of Vanillin in a Pervaporation Reactor  

PubMed Central

In membrane reactors, the interaction of reaction and membrane separation can be exploited to achieve a “process intensification”, a key objective of sustainable development. In the present work, the properties that the membrane must have to obtain this result in a pervaporation reactor are analyzed and discussed. Then, the methods to enhance these properties are investigated for the photocatalytic synthesis of vanillin, which represents a case where the recovery from the reactor of vanillin by means of pervaporation while it is produced allows a substantial improvement of the yield, since its further oxidation is thus prevented. To this end, the phenomena that control the permeation of both vanillin and the reactant (ferulic acid) are analyzed, since they ultimately affect the performances of the membrane reactor. The results show that diffusion of the aromatic compounds takes place in the presence of low concentration gradients, so that the process is controlled by other phenomena, in particular by the equilibrium with the vapor at the membrane-permeate interface. On this basis, it is demonstrated that the performances are enhanced by increasing the membrane thickness and/or the temperature, whereas the pH begins to limit the process only at values higher than 6.5. PMID:24957123

Camera-Roda, Giovanni; Cardillo, Antonio; Loddo, Vittorio; Palmisano, Leonardo; Parrino, Francesco

2014-01-01

199

Anaerobic co-digestion of the organic fraction of municipal solid waste with FOG waste from a sewage treatment plant: Recovering a wasted methane potential and enhancing the biogas yield  

SciTech Connect

Anaerobic digestion is applied widely to treat the source collected organic fraction of municipal solid wastes (SC-OFMSW). Lipid-rich wastes are a valuable substrate for anaerobic digestion due to their high theoretical methane potential. Nevertheless, although fat, oil and grease waste from sewage treatment plants (STP-FOGW) are commonly disposed of in landfill, European legislation is aimed at encouraging more effective forms of treatment. Co-digestion of the above wastes may enhance valorisation of STP-FOGW and lead to a higher biogas yield throughout the anaerobic digestion process. In the present study, STP-FOGW was evaluated as a co-substrate in wet anaerobic digestion of SC-OFMSW under mesophilic conditions (37 {sup o}C). Batch experiments carried out at different co-digestion ratios showed an improvement in methane production related to STP-FOGW addition. A 1:7 (VS/VS) STP-FOGW:SC-OFMSW feed ratio was selected for use in performing further lab-scale studies in a 5 L continuous reactor. Biogas yield increased from 0.38 {+-} 0.02 L g VS{sub feed}{sup -1} to 0.55 {+-} 0.05 L g VS{sub feed}{sup -1} as a result of adding STP-FOGW to reactor feed. Both VS reduction values and biogas methane content were maintained and inhibition produced by long chain fatty acid (LCFA) accumulation was not observed. Recovery of a currently wasted methane potential from STP-FOGW was achieved in a co-digestion process with SC-OFMSW.

Martin-Gonzalez, L., E-mail: lucia.martin@uab.ca [Departament d'Enginyeria Quimica, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Colturato, L.F. [Departament d'Enginyeria Quimica, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Font, X.; Vicent, T. [Departament d'Enginyeria Quimica, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Institut de Ciencia i Tecnologia Ambiental (ICTA) Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain)

2010-10-15

200

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

201

Performance Evaluation of Passive Safety Injection Flow Controllers for the APR1400 Reactor  

SciTech Connect

This paper provides experimental results obtained in the full-scale tests for the performance evaluation of the Fluidic Device which is expected to be adopted in a Korean next generation reactor (APR1400). The tests have been carried out using the full-scale test facility called VAPER (Valve Performance Evaluation test Rig). Following characteristics of the fluidic device are investigated in the present work: peak discharge flow rate, duration of high flow, flow rate switching function, water level depression in stand pipe, etc. Experimental results show that the present fluidic device meets the primary performance requirements of APR1400 plant design. (authors)

Chu, I.C.; Chung, H.J.; Park, W.M.; Song, C.H.; Park, J.K. [Korea Atomic Energy Research Institute, 150, Dukjin-Dong, Yusong-Gu, Taejon 305-353 (Korea, Republic of)

2002-07-01

202

Codigestion of manure and organic wastes in centralized biogas plants  

Microsoft Academic Search

Centralized biogas plants in Denmark codigest mainly manure, together with other organic waste such as industrial organic\\u000a waste, source sorted household waste, and sewage sludge. Today 22 large-scale centralized biogas plants are in operation in\\u000a Denmark, and in 2001 they treated approx 1.2 million tons of manure as well as approx 300,000 of organic industrial waste.\\u000a Besides the centralized biogas

I. Angelidaki; L. Ellegaard

2003-01-01

203

Biogas Potential in the United States (Fact Sheet)  

SciTech Connect

Biogas has received increased attention as an alternative energy source in the United States. The factsheet provides information about the biogas (methane) potential from various sources in the country (by county and state) and estimates the power generation and transportation fuels production (renewable natural gas) potential from these biogas sources. It provides valuable information to the industry, academia and policy makers in support of their future decisions.

Not Available

2013-10-01

204

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

205

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

206

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

207

Catalytic hydrogenation of o-nitroanisole in a microreactor: Reactor performance and kinetic studies  

Microsoft Academic Search

Hydrogenation of o-nitroanisole to o-anisidine was conducted in a packed-bed microreactor as a model hydrogenation reaction of importance to the pharmaceutical and fine chemicals industries with the aim of investigating the reactor performance and kinetics of the reaction. The effects of different processing conditions viz. hydrogen pressure, o-nitroanisole concentration, temperature, and residence time on the conversion of o-nitroanisole, space-time yield

Sunitha Tadepalli; Raghunath Halder; Adeniyi Lawal

2007-01-01

208

Climate balance of biogas upgrading systems  

SciTech Connect

One of the numerous applications of renewable energy is represented by the use of upgraded biogas where needed by feeding into the gas grid. The aim of the present study was to identify an upgrading scenario featuring minimum overall GHG emissions. The study was based on a life-cycle approach taking into account also GHG emissions resulting from plant cultivation to the process of energy conversion. For anaerobic digestion two substrates have been taken into account: (1) agricultural resources and (2) municipal organic waste. The study provides results for four different upgrading technologies including the BABIU (Bottom Ash for Biogas Upgrading) method. As the transport of bottom ash is a critical factor implicated in the BABIU-method, different transport distances and means of conveyance (lorry, train) have been considered. Furthermore, aspects including biogas compression and energy conversion in a combined heat and power plant were assessed. GHG emissions from a conventional energy supply system (natural gas) have been estimated as reference scenario. The main findings obtained underlined how the overall reduction of GHG emissions may be rather limited, for example for an agricultural context in which PSA-scenarios emit only 10% less greenhouse gases than the reference scenario. The BABIU-method constitutes an efficient upgrading method capable of attaining a high reduction of GHG emission by sequestration of CO{sub 2}.

Pertl, A., E-mail: andreas.pertl@boku.ac.a [Institute of Waste Management, Department of Water, Atmosphere and Environment, University of Natural Resources and Applied Life Sciences, Vienna, Muthgasse 107, A-1190 Wien (Austria); Mostbauer, P.; Obersteiner, G. [Institute of Waste Management, Department of Water, Atmosphere and Environment, University of Natural Resources and Applied Life Sciences, Vienna, Muthgasse 107, A-1190 Wien (Austria)

2010-01-15

209

Biogas and energy production from cattle waste  

SciTech Connect

Biomass is one of the longest used energy sources employed in human activity. The bioconversion of organic matter to biogas is a complex anaerobic fermentation process involving the action of microorganisms such as methane producing bacteria. In this paper, biogas and energy production from cattle waste is investigated. There are two significant reasons that motivate this study. First, treating animal waste with the technology of anaerobic digestion can reduce environmental pollution and generate a relatively cheap and easily available source of energy in dairy farms. The gas produced can be used for space and water heating of farm houses, cooking, lighting, grain drying and as a fuel for heating greenhouses during cold weather. It also has the potential to run other small industries. Second, it is an effective way of managing cattle waste as well as producing a quick acting, non-toxic fertilizer for agricultural use. A working model of biogas plant is studied in this paper and its economic value as an alternative energy source is examined. An alternative to direct generation of electricity, is to convert the methane from the biomass to methanol. Methanol is an excellent fuel for internal combustion engines and can easily compete with gasoline in many nations where gasoline costs over $4 per US gallon.

Chakravarthi, J. [Hood Coll., Frederick, MD (United States). Dept. of Environmental Biology

1997-12-31

210

Chemical-oxidative scrubbing for the removal of hydrogen sulphide from raw biogas: potentials and economics.  

PubMed

In the present work chemical-oxidative scrubbing as a novel method for the desulphurisation of raw biogas is presented with a special focus on the process potentials and economics. The selective absorption of hydrogen sulphide from gas streams containing high amounts of carbon dioxide using caustic solutions is not trivial but has been treated in literature. However, the application of this method to biogas desulphurisation has not been established so far. Based on rigorous experimental work, an industrial-scale pilot plant has been designed, erected and commissioned at a biogas plant with biogas upgrading and gas grid injection in Austria. Data collected from the 12-month monitored operation has been used to elaborate performance as well as economic parameters for the novel desulphurisation method. The proposed technology offers significant operational advantages regarding the degree of automation and the flexibility towards fluctuations in process boundary conditions. Furthermore, the economic assessment revealed the high competitiveness of the chemical-oxidative scrubbing process compared with other desulphurisation technologies with the named advantageous operational behaviour. PMID:22828317

Miltner, M; Makaruk, A; Krischan, J; Harasek, M

2012-01-01

211

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

212

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

213

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

214

Comparative performance of a UASB reactor and an anaerobic packed-bed reactor when treating potato waste leachate  

Microsoft Academic Search

The results presented in this paper are from studies on a laboratory-scale upflow anaerobic sludge blanket (UASB) reactor and an anaerobic packed-bed (APB) reactor treating potato leachate at increasing organic loading rates from 1.5 to 7.0gCOD\\/1\\/day. The hydraulic retention times ranged from 13.2 to 2.8 days for both reactors during the 100 days of the experiment. The maximum organic loading

W. Parawira; M. Murto; R. Zvauya; B. Mattiasson

2006-01-01

215

Treatment of a chocolate industry wastewater in a pilot-scale low-temperature UASB reactor operated at short hydraulic and sludge retention time.  

PubMed

The aim of this work was to evaluate the performance of a 244-L pilot-scale upflow anaerobic sludge blanket (UASB) reactor during the treatment of chocolate-processing industry wastewater under low-temperature conditions (18 ± 0.6 °C) for approximately 250 d. The applied organic loading rate (OLR) was varied between 4 and 7 kg/m(3)/d by varying the influent soluble chemical oxygen demand (CODsol), while keeping the hydraulic retention time constant (6.4 ± 0.3 h). The CODsol removal efficiency was low (59-78%). The measured biogas production increased from 240 ± 54 to 431 ± 61 L/d during the experiments. A significant linear correlation between the measured biogas production and removed OLR indicated that 81.69 L of biogas were produced per kg/m(3) of CODsol removed. Low average reactor volatile suspended solids (VSS) (2,700-4,800 mg/L) and high effluent VSS (177-313 mg/L) were derived in a short sludge retention time (SRT) (4.9 d). The calculated SRT was shorter than those reported in the literature, but did not affect the reactor's performance. Average sludge yield was 0.20 kg-VSS/kg-CODsol. The low-temperature anaerobic treatment was a good option for the pre-treatment of chocolate-processing industry wastewater. PMID:23508162

Esparza-Soto, M; Arzate-Archundia, O; Solís-Morelos, C; Fall, C

2013-01-01

216

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

217

Full scale performance of compost's leachate treatment by biological anaerobic reactors.  

PubMed

A wide range of treatment processes have been applied to leachate treatment with varying success. The aim of this research was to examine the performance of two hybrid biological anaerobic reactors in a new full-scale leachate treatment plant in Rasht composting facility, north of Iran. The studied plant was operated for nearly 12 months and treated up to 50 m(3) day(-1) of fresh compost leachate with a relatively high BOD(5) to COD ratio of around 0.5. The average COD of the raw leachate was measured to be 81?000?mg L(-1). 30% of effective volume of each reactor was filled with clay blocks with a specific area of 87?m(2)?m(-3) as the fixed bed. The sequencing of reactors was down flow and up flow, respectively. The maximum COD removal efficiency of 91% was achieved with 4.5?kg COD m(-3?)day(-1) of organic loading rate and 7500?mg L(-1) of volatile suspended solids. There was no significant difference in COD removal efficiency when the reactors were operated with an organic load between 2 and 5?kg COD m(-3?)day(-1). Increasing the volumetric organic loading rate to greater than 6?kg COD m(-3?)day(-1) caused a considerable reduction of COD removal efficiency. The COD removal efficiency decreased to less than 70% when the organic load rose to 10.8?kg COD m(-3?)day(-1). Nevertheless, hybrid anaerobic reactors proved to be a feasible technique for the reduction of organic load from the composting leachate which was the subject of this study. PMID:21987411

Mokhtarani, Nader; Bayatfard, Asghar; Mokhtarani, Babak

2012-05-01

218

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 multi-physics 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 multi-physics framework. Good agreement is shown with benchmarks and problems from the literature of RIAs and LOCAs for the tools used. (authors)

Banfield, J. E. [Dept. of Nuclear Engineering, Univ. of Tennessee, Knoxville, TN 37996-2300 (United States); Clarno, K. T.; Hamilton, S. P. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Maldonado, G. I. [Dept. of Nuclear Engineering, Univ. of Tennessee, Knoxville, TN 37996-2300 (United States); Philip, B.; Baird, M. L. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

2012-07-01

219

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

2012-01-01

220

Performance and emissions of a catalytic reactor with propane, diesel, and Jet A fuels  

NASA Technical Reports Server (NTRS)

Tests were made to determine the performance and emissions of a catalytic reactor operated with propane, No. 2 diesel, and Jet A fuels. A 12-cm diameter and 16-cm long catalytic reactor using a proprietary noble metal catalyst was operated at an inlet temperature of 800 K, a pressure of 300,000 Pa and reference velocities of 10 to 15 m/s. No significant differences between the performance of the three fuels were observed when 98.5 percent purity propane was used. The combustion efficiency for 99.8-percent purity propane tested later was significantly lower, however. The diesel fuel contained 135 ppm of bound nitrogen and consequently produced the highest NOx emissions of the three fuels. As much as 85 percent of the bound nitrogen was converted to NOx. Steady-state emissions goals based on half the most stringent proposed automotive standards were met when the reactor was operated at an adiabatic combustion temperature higher than 1350 K with all fuels except the 99.8-percent purity propane. With that fuel, a minimum temperature of 1480 K was required.

Anderson, D. N.

1977-01-01

221

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 C. The CFD model with 1/6-g predicts a maximum water temperature of 88 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.

REID, ROBERT S. [Los Alamos National Laboratory; PEARSON, J. BOSIE [Los Alamos National Laboratory; STEWART, ERIC T. [Los Alamos National Laboratory

2007-01-16

222

Steam generator materials performance in high temperature gas-cooled reactors  

SciTech Connect

High temperature gas-cooled reactor (HTGR) systems feature a graphite-moderated, uranium-thorium, all-ceramic core and utilize high pressure helium as the primary coolant. The steam generators in these systems are exposed to gas-side temperatures approaching 760/degree/C (1400/degree/F) and produce superheated steam at 538/degree/C (1000/degree/F) and 16.5 MPa (2400 psi). Thus, the design and development of steam generators for these systems require consideration of time-dependent materials behavior, corrosion, fretting, wear, and other related phenomena of concern in all steam generators. This paper focuses on materials performance of the units that feature modern steam generators, and pays most attention to the Peach Bottom and FSV (Fort St. Vrain) reactors, although other systems are referred to when appropriate. 1 ref.

Chafey, J.E.; Roberts, D.I.

1981-10-01

223

Particle bed reactor propulsion vehicle performance and characteristics as an orbital transfer rocket  

SciTech Connect

The particle bed reactor designed for 100 to 300 MW power output using hydrogen as a coolant is capable of specific impulses up to 1000 seconds as a nuclear rocket. A single space shuttle compatible vehicle can perform extensive missions from LEO to 3 times GEO and return with multi-ton payloads. The use of hydrogen to directly cool particulate reactor fuel results in a compact, lightweight rocket vehicle, whose duration of usefulness is dependent only upon hydrogen resupply availability. The LEO to GEO mission had a payload capability of 15.4 metric tons with 3.4 meters of shuttle bay. To increase the volume limitation of the shuttle bay, the use of ammonia in the initial boost phase from LEO is used to give greater payload volume with a small decrease in payload mass, 8.7 meters and 12.7 m-tons. 5 refs., 15 figs.

Horn, F.L.; Powell, J.R.; Lazareth, O.W.

1986-01-01

224

Design and optimization of a back-flow limiter for the high performance light water reactor  

SciTech Connect

Design and Analysis of a back-flow limiter are presented, which is implemented as a safety device in the four inlet lines of the Reactor Pressure Vessel (RPV) of the High Performance Light Water Reactor (HPLWR). As a passive component, the back-flow limiter has no moving parts and belongs to the group of fluid diodes. It has low flow resistance for regular operation condition and a high flow resistance when the flow direction is reversed which is the case if a break of the feedwater line occurs. The increased flow resistance is due to a substantially increased swirl for reverse flow condition. The design is optimized employing 1D flow analyses in combination with 3D CFD analyses with respect to geometrical modifications, like the nozzle shape and swirler angles. (authors)

Fischer, Kai [EnBW Kernkraft GmbH, Kernkraftwerk Philippsburg, D-76661 Philippsburg (Germany); Laurien, Eckart [University of Stuttgart, Institute for Nuclear Energy and Energy Systems, D-70569 Stuttgart (Germany); Claas, Andreas G.; Schulenberg, Thomas [Forschungszentrum Karlsruhe GmbH, Institute for Nuclear and Energy Technologies, D-76021 Karlsruhe (Germany)

2007-07-01

225

Steam generator tube performance: world experience with water-cooled nuclear power reactors during 1979  

SciTech Connect

The performance of steam generator tubes in water-cooled nuclear power reactors is reviewed for 1979. Tube failures occurred at 38 of the 93 reactors surveyed. The causes of these failures and the procedures designed to deal with them are described. The defect rate, although higher than that in 1978, was still lower than the rates of the two previous years. Methods being employed to detect defects include the increased use of multifrequency eddy-current testing and a trend to full-length inspection of all tubes. To reduce the incidence of tube failure by corrosion, plant operators are turning to full-flow condensate demineralization and more leak-resistant condenser tubes. 10 tables.

Tatone, O.S.; Pathania, R.S.

1981-09-01

226

Influence of fast alpha diffusion and thermal alpha buildup on tokamak reactor performance  

SciTech Connect

The effect of fast alpha diffusion and thermal alpha accumulation on the confinement capability of a candidate Engineering Test Reactor (ETR) plasma (Tokamak Ignition/Burn Experimental Reactor (TIBER-II)) in achieving ignition and steady-state driven operation has been assessed using both global and 1-1/2-D transport models. Estimates are made of the threshold for radial diffusion of fast alphas and thermal alpha buildup. It is shown that a relatively low level of radial transport, when combined with large gradients in the fast alpha density, leads to a significant radial flow with a deleterious effect on plasma performance. Similarly, modest levels of thermal alpha concentration significantly influence the ignition and steady-state burn capability. 23 refs., 9 figs., 4 tabs.

Uckan, N.A.; Tolliver, J.S.; Houlberg, W.A.; Attenberger, S.E.

1987-11-01

227

Integrated application of upflow anaerobic sludge blanket reactor for the treatment of wastewaters.  

PubMed

The UASB process among other treatment methods has been recognized as a core method of an advanced technology for environmental protection. This paper highlights the treatment of seven types of wastewaters i.e. palm oil mill effluent (POME), distillery wastewater, slaughterhouse wastewater, piggery wastewater, dairy wastewater, fishery wastewater and municipal wastewater (black and gray) by UASB process. The purpose of this study is to explore the pollution load of these wastewaters and their treatment potential use in upflow anaerobic sludge blanket process. The general characterization of wastewater, treatment in UASB reactor with operational parameters and reactor performance in terms of COD removal and biogas production are thoroughly discussed in the paper. The concrete data illustrates the reactor configuration, thus giving maximum awareness about upflow anaerobic sludge blanket reactor for further research. The future aspects for research needs are also outlined. PMID:21764417

Latif, Muhammad Asif; Ghufran, Rumana; Wahid, Zularisam Abdul; Ahmad, Anwar

2011-10-15

228

Commercial-Scale Performance Predictions for High-Temperature Electrolysis Plants Coupled to Three Advanced Reactor Types  

SciTech Connect

This report presents results of system analyses that have been developed to assess the hydrogen production performance of commercial-scale high-temperature electrolysis (HTE) plants driven by three different advanced reactor – power-cycle combinations: a high-temperature helium cooled reactor coupled to a direct Brayton power cycle, a supercritical CO2-cooled reactor coupled to a direct recompression cycle, and a sodium-cooled fast reactor coupled to a Rankine cycle. The system analyses were performed using UniSim software. The work described in this report represents a refinement of previous analyses in that the process flow diagrams include realistic representations of the three advanced reactors directly coupled to the power cycles and integrated with the high-temperature electrolysis process loops. In addition, this report includes parametric studies in which the performance of each HTE concept is determined over a wide range of operating conditions. Results of the study indicate that overall thermal-to- hydrogen production efficiencies (based on the low heating value of the produced hydrogen) in the 45 - 50% range can be achieved at reasonable production rates with the high-temperature helium cooled reactor concept, 42 - 44% with the supercritical CO2-cooled reactor and about 33 - 34% with the sodium-cooled reactor.

M. G. McKellar; J. E. O'Brien; J. S. Herring

2007-09-01

229

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

230

Biogas plasticization coupled anaerobic digestion: continuous flow anaerobic pump test results.  

PubMed

In this investigation, the Anaerobic Pump (TAP) and a conventional continuous flow stirred tank reactor (CFSTR) were tested side by side to compare performance. TAP integrates anaerobic digestion (AD) with biogas plasticization-disruption cycle to improve mass conversion to methane. Both prototypes were fed a "real world" 50:50 mixture of waste-activated sludge (WAS) and primary sludge and operated at room temperature (20 degrees Celsius). The quantitative results from three steady states show TAP peaked at 97% conversion of the particulate COD in a system hydraulic residence time (HRT) of only 6 days. It achieved a methane production of 0.32 STP cubic meter CH(4) per kilogram COD fed and specific methane yield of 0.78 m(3) CH(4) per cubic meter per day. This was more than three times the CFSTR specific methane yield (0.22 m(3) CH(4) per cubic meter per day) and more than double the CFSTR methane production (0.15 m(3) CH(4) per kilogram COD fed). A comparative kinetics analysis showed the TAP peak substrate COD removal rate (R (o)) was 2.24 kg COD per cubic meter per day, more than three times the CFSTR substrate removal rate of 0.67 kg COD per cubic meter per day. The three important factors contributing to the superior TAP performance were (1) effective solids capture (96%) with (2) mass recycle and (3) stage II plasticization-disruption during active AD. The Anaerobic Pump (TAP) is a high rate, high efficiency-low temperature microbial energy engine that could be used to improve renewable energy yields from classic AD waste substrates like refuse-derived fuels, treatment plant sludges, food wastes, livestock residues, green wastes and crop residuals. PMID:19455433

Schimel, Keith A; Boone, David R

2010-03-01

231

ANALYSIS OF SEPCTRUM CHOICES FOR SMALL MODULAR REACTORS-PERFORMANCE AND DEVELOPMENT  

E-print Network

. The research mainly focused on producing a small modular reactor (Pebble Bed Modular Reactor) design to analyze the fuel depletion and plutonium and minor actinide accumulation with varying power densities. The reactors running at low power densities were found...

Kafle, Nischal

2011-04-26

232

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.

233

Energy Efficiency of Biogas Produced from Different Biomass Sources  

NASA Astrophysics Data System (ADS)

Malaysia has different sources of biomass like palm oil waste, agricultural waste, cow dung, sewage waste and landfill sites, which can be used to produce biogas and as a source of energy. Depending on the type of biomass, the biogas produced can have different calorific value. At the same time the energy, being used to produce biogas is dependent on transportation distance, means of transportation, conversion techniques and for handling of raw materials and digested residues. An energy systems analysis approach based on literature is applied to calculate the energy efficiency of biogas produced from biomass. Basically, the methodology is comprised of collecting data, proposing locations and estimating the energy input needed to produce biogas and output obtained from the generated biogas. The study showed that palm oil and municipal solid waste is two potential sources of biomass. The energy efficiency of biogas produced from palm oil residues and municipal solid wastes is 1.70 and 3.33 respectively. Municipal solid wastes have the higher energy efficiency due to less transportation distance and electricity consumption. Despite the inherent uncertainties in the calculations, it can be concluded that the energy potential to use biomass for biogas production is a promising alternative.

Begum, Shahida; Nazri, A. H.

2013-06-01

234

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

235

DEVELOPMENT OF AN AFFORDABLE FAMILY-SCALE BIOGAS GENERATOR  

EPA Science Inventory

From laboratory experiments we calculated that our system would have to deliver 262 liters/hr of biogas to cook a meal. Biogas produced by slurries of various wastes was measured with a two liter bench-top digester system designed by the team. Gas volume was measured by displa...

236

Biogas systems in India: is the technology appropriate  

Microsoft Academic Search

In 1973 the Indian government launched a project to install 50,000 biogas plants in villages by 1978. About 36,000 plants were in operation by 1977. Biogas technology was seen as providing a valuable source of energy and fertilizer, helping to conserve forests and preventing soil erosion, improving India's balance of payments and improving rural sanitation and public health. As it

1982-01-01

237

Energy balance model of a SOFC cogenerator operated with biogas  

Microsoft Academic Search

A small cogeneration system based on a Solid Oxide Fuel Cell (SOFC) fed on the renewable energy source biogas is presented. An existing farm biogas production site (35m3 per day), currently equipped with a SOFC demonstration stack, is taken for reference. A process flow diagram was defined in a software package allowing to vary system operating parameters like the fuel

Jan Van herle; F. Maréchal; S. Leuenberger; D. Favrat

2003-01-01

238

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

239

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

240

BIOGAS PLANT INVESTMENT ANALYSIS, COST BENEFIT AND MAIN FACTORS  

Microsoft Academic Search

The establishment of a biogas station is possible only with a large investment and a good answer to these main questions. 1. Would it be profitable? 2. What are the risks? 3. Is the current support for the establishment of a biogas station sufficient? 4. What are the main factors, which the funding depends on? 5. Is the current buying

Andres Menind; Jüri Olt

2009-01-01

241

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

242

Performance evaluation of anaerobic hybrid reactors with different packing media for treating wastewater of mild alkali treated rice straw in ethanol fermentation process.  

PubMed

Four anaerobic hybrid reactors with different packing media viz. gravel (R1), pumice stone (R2), polypropylene saddles (R3) and ceramic saddles (R4) were operated in semi-continuous mode. Biomethanation potential of the wastewater generated during alkali-treatment of rice straw in ethanol production process was investigated at ambient conditions. The reactors were operated with varying organic loading rates (0.861-4.313 g COD l(-1) d(-1)) and hydraulic retention time (3-15 days). Higher COD removal efficiency (69.2%) and methane yield (0.153 l CH4 g(-1) CODadded) were achieved in reactor R2 at 15 days HRT. Modified Stover-Kincannon model was applied to estimate the bio-kinetic coefficients and fitness of the model was checked by the regression coefficient for all the reactors. The model showed an excellent correlation between the experimental and predicted values. The present study demonstrated the treatment of wastewater from alkali treated rice straw for production of biogas. PMID:24291309

Narra, Madhuri; Balasubramanian, Velmurugan; Mehta, Himali; Dixit, Garima; Madamwar, Datta; Shah, Amita R

2014-01-01

243

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

SciTech Connect

Parque Porcino de Ventanilla has an extension of 840 ha 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 (225 L 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.

Ferrer, I. [Environmental Engineering Division, Department of Hydraulic Maritime and Environmental Engineering, Technical University of Catalonia (UPC), C/Jordi Girona 1-3, Modul D1, 08034 Barcelona (Spain); GIRO Technological Center, Rambla Pompeu Fabra 1, 08100 Mollet del Valles, Barcelona (Spain)], E-mail: ivet.ferrer@upc.edu; Gamiz, M. [Environmental Engineering Division, Department of Hydraulic Maritime and Environmental Engineering, Technical University of Catalonia (UPC), C/Jordi Girona 1-3, Modul D1, 08034 Barcelona (Spain); Almeida, M.; Ruiz, A. [Ciudad Saludable NLO, Av. Jorge Basadre 255, Of. 401, Lima 27 (Peru)

2009-01-15

244

On the factors influencing the performance of solar reactors for water disinfection with photosensitized singlet oxygen.  

PubMed

Two solar reactors based on compound parabolic collectors (CPCs) were optimized for water disinfection by photosensitized singlet oxygen (1O2) production in the heterogeneous phase. Sensitizing materials containing Ru(II) complexes immobilized on porous silicone were produced, photochemically characterized, and successfully tested for the inactivation of up to 10(4) CFU mL(-1) of waterborne Escherichia coli (gram-negative) or Enterococcus faecalis (gram-positive) bacteria. The main factors determining the performance of the solar reactors are the type of photosensitizing material, the sensitizer loading, the CPC collector geometry (fin- vs coaxial-type), the fluid rheology, and the balance between concurrent photothermal--photolytic and 1O2 effects on the microorganisms' inactivation. In this way, at the 40 degrees N latitude of Spain, water can be disinfected on a sunny day (0.6-0.8 MJ m(-2) L(-1) accumulated solar radiation dose in the 360-700 nm range, typically 5-6 h of sunlight) with a fin-type reactor containing 0.6 m2 of photosensitizing material saturated with tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) (ca. 2.0 g m(-2)). The optimum rheological conditions require laminar-to-transitional water flow in both prototypes. The fin-type system showed better inactivation efficiency than the coaxial reactor due to a more important photolytic contribution. The durability of the sensitizing materials was tested and the operational lifetime of the photocatalyst is at least three months without any reduction in the bacteria inactivation efficiency. Solar water disinfection with 1O2-generating films is demonstrated to be an effective technique for use in isolated regions of developing countries with high yearly average sunshine. PMID:18350912

Manjón, Francisco; Villén, Laura; García-Fresnadillo, David; Orellana, Guillermo

2008-01-01

245

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

246

Effect of auxotrophies on yeast performance in aerated fed-batch reactor  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer The paper contributes to fill the gap existing between the basic and applied research. Black-Right-Pointing-Pointer Mathematical model sheds light on the physiology of auxotrophic yeast strains. Black-Right-Pointing-Pointer Yeast behavior in fed-batch is influenced by biological and environmental determinants. Black-Right-Pointing-Pointer Process optimization would make possible the production of heterologous proteins which are not yet on the market. -- Abstract: A systematic investigation on the effects of auxotrophies on the performance of yeast in aerated fed-batch reactor was carried out. Six isogenic strains from the CEN.PK family of Saccharomyces cerevisiae, one prototroph and five auxotrophs, were grown in aerated fed-batch reactor using the same operative conditions and a proper nutritional supplementation. The performance of the strains, in terms of final biomass decreased with increasing the number of auxotrophies. Auxotrophy for leucine exerted a profound negative effect on the performance of the strains. Accumulation of reactive oxygen species (ROS) in the cells of the strain carrying four auxotrophies and its significant viability loss, were indicative of an oxidative stress response induced by exposure of cells to the environmental conditions. The mathematical model was fundamental to highlight how the carbon flux, depending on the number and type of auxotrophies, was diverted towards the production of increasingly large quantities of energy for maintenance.

Landi, Carmine; Paciello, Lucia [Dept. Ingegneria Industriale, Universita di Salerno, Via Ponte Don Melillo, 84084 Fisciano, Salerno (Italy)] [Dept. Ingegneria Industriale, Universita di Salerno, Via Ponte Don Melillo, 84084 Fisciano, Salerno (Italy); Alteriis, Elisabetta de [Dept. Biologia Strutturale e Funzionale, Universita degli Studi di Napoli 'Federico II', Via Cinthia, 80100 Napoli (Italy)] [Dept. Biologia Strutturale e Funzionale, Universita degli Studi di Napoli 'Federico II', Via Cinthia, 80100 Napoli (Italy); Brambilla, Luca [Dept. Biotecnologie e Bioscienze, Universita Milano-Bicocca, Piazza della Scienza, 20126 Milano (Italy)] [Dept. Biotecnologie e Bioscienze, Universita Milano-Bicocca, Piazza della Scienza, 20126 Milano (Italy); Parascandola, Palma, E-mail: pparascandola@unisa.it [Dept. Ingegneria Industriale, Universita di Salerno, Via Ponte Don Melillo, 84084 Fisciano, Salerno (Italy)] [Dept. Ingegneria Industriale, Universita di Salerno, Via Ponte Don Melillo, 84084 Fisciano, Salerno (Italy)

2011-10-28

247

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

248

Household biogas use in rural China: A study of opportunities and constraints  

Microsoft Academic Search

As a renewable energy, biogas is not only an important part of the development of rural new energy, but also an important aspect of sustainable development in China. The development process and present status of household biogas, specifically the opportunities and constraints of household biogas in rural China, are discussed in this paper. Only about 19% of the biogas potential

Yu Chen; Gaihe Yang; Sandra Sweeney; Yongzhong Feng

2010-01-01

249

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

250

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

251

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

252

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

2004-12-01

253

Management of various organic fractions of municipal solid waste via recourse to VFA and biogas generation.  

PubMed

A hybrid anaerobic solid-liquid system was used for anaerobic digestion of organic fraction of municipal solid waste (OFMSW) consisting of mixed food + fruit waste and vegetable waste. Hydrolysis and acidogenesis potential of the above wastes were evaluated with the aim of producing value-added products in the form of volatile fatty acids (VFAs) and biogas recovery. Efficient hydrolysis and acidogenesis of mixed food + fruit waste was observed at a hydraulic retention time (HRT) of 1-3 d with a five-fold increase in soluble chemical oxygen demand (SCOD) followed by VFA production consisting of 50-75% acetic acid. Longer time was required for hydrolysis of vegetable waste with optimum hydrolysis and SCOD generation at 9 d HRT followed by VFA synthesis consisting of 45% acetic acid. Higher inoculum:substrate ratios resulted in improved hydrolysis and acidogenesis rates for vegetable waste in shorter time of 6 d with higher VFA production and increase in acetic acid content to 70%. When acidogenic leachate was fed into methanogenic reactors, detectable biogas production was observed after 25 d with 37-53% SCOD removal from leachate from mixed food + fruit waste and methane production of 0.066-0.1 L g(-1) SCOD removed and methane content of 38%. Though biogas yield from acidogenic leachate from vegetable waste was lower, nearly 94% volatile solids (VS) removal was observed in the reactors thereby providing methane yield of 0.13-0.21 L g(-1) VS consumed. Thus, the study provided a method for generation of value-added products from an otherwise misplaced resource in the form of OFMSW. PMID:24350462

Khardenavis, Anshuman Arun; Wang, Jing Yuan; Ng, Wun Jern; Purohit, Hemant J

2013-01-01

254

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. PMID:24031316

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

2009-01-01

255

Performance of the solid deuterium ultra-cold neutron source at the pulsed reactor TRIGA Mainz  

E-print Network

The performance of the solid deuterium ultra-cold neutron source at the pulsed reactor TRIGA Mainz with a maximum peak energy of 10 MJ is described. The solid deuterium converter with a volume of V=160 cm3 (8 mol), which is exposed to a thermal neutron fluence of 4.5x10^13 n/cm2, delivers up to 550 000 UCN per pulse outside of the biological shield at the experimental area. UCN densities of ~ 10/cm3 are obtained in stainless steel bottles of V ~ 10 L resulting in a storage efficiency of ~20%. The measured UCN yields compare well with the predictions from a Monte Carlo simulation developed to model the source and to optimize its performance for the upcoming upgrade of the TRIGA Mainz into a user facility for UCN physics.

Karch, J; Beck, M; Eberhardt, K; Hampel, G; Heil, W; Kieser, R; Reich, T; Trautmann, N; Ziegner, M

2013-01-01

256

Performance of the solid deuterium ultra-cold neutron source at the pulsed reactor TRIGA Mainz  

NASA Astrophysics Data System (ADS)

The performance of the solid deuterium ultra-cold neutron (UCN) source at the pulsed reactor TRIGA Mainz with a maximum peak energy of 10MJ is described. The solid deuterium converter with a volume of cm3 (8mol), which is exposed to a thermal neutron fluence of n/cm2, delivers up to 240000 UCN ( m/s) per pulse outside the biological shield at the experimental area. UCN densities of 10 cm3 are obtained in stainless-steel bottles of 10 L. The measured UCN yields compare well with the predictions from a Monte Carlo simulation developed to model the source and to optimize its performance for the upcoming upgrade of the TRIGA Mainz into a user facility for UCN physics.

Karch, J.; Sobolev, Yu.; Beck, M.; Eberhardt, K.; Hampel, G.; Heil, W.; Kieser, R.; Reich, T.; Trautmann, N.; Ziegner, M.

2014-04-01

257

Sludge storage lagoon biogas recovery and use. Volume 2  

SciTech Connect

The City of Memphis has two wastewater treatment plants. The SWTP employs two large anaerobic digestion sludge lagoons as part of the overall sludge treatment system. Although these lagoons are effective in concentrating and digesting sludge, they can generate offensive odors. The SWTP uses aerobic digesters to partially stabilize the sludge and help reduce objectionable odors before it enters the lagoons. The anaerobic digestion of sludge in the lagoons results in the dispersion of a large quantity of biogas into the atmosphere. The City realized that if the lagoons could be covered, the odor problem could be resolved, and at the same, time, biogas could be recovered and utilized as a source of energy. In 1987, the City commissioned ADI International to conduct a feasibility study to evaluate alternative methods of covering the lagoons and recovering and utilizing the biogas. The study recommended that the project be developed in two phases: (1) recovery of the biogas and (2) utilization of the biogas. Phase 1 consists of covering the two lagoons with an insulated membrane to control odor and temperature and collect the biogas. Phase 1 was found to be economically feasible and offered a unique opportunity for the City to save substantial operating costs at the treatment facility. The Memphis biogas recovery project is the only application in the world where a membrane cover has been used on a municipal wastewater sludge lagoon. It is also the largest lagoon cover system in the world.

Muller, D.; Norville, C. [Memphis and Shelby County Div. of Planning and Development, TN (United States)

1991-07-01

258

The effect of shock loading on the performance of a thermophilic anaerobic contact reactor at constant organic loading rate  

PubMed Central

The influences of organic loading disturbances on the process performance of a thermophilic anaerobic contact reactor treating potato-processing wastewater were investigated. For this purpose, while the reactor was operated at steady state conditions with organic loading rate of 5.5 kg COD/m3?·?day, an instant acetate concentration increase (1 g/L) was introduced to the reactor. During the shock loading test of acetate, it was observed that the overall process performance was adversely affected by all the shock loading, however, the system reached steady state conditions less than 24 hours of operation indicating that thermophilic anaerobic contact reactor is resistant to shock loading and be capable of returning its normal conditions within a short time period. PMID:24872886

2014-01-01

259

Nitritation performance and biofilm development of co- and counter-diffusion biofilm reactors: Modeling and experimental comparison  

Microsoft Academic Search

A comparative study was conducted on the start-up performance and biofilm development in two different biofilm reactors with aim of obtaining partial nitritation. The reactors were both operated under oxygen limited conditions, but differed in geometry. While substrates (O2, NH3) co-diffused in one geometry, they counter-diffused in the other. Mathematical simulations of these two geometries were implemented in two 1-D

Rongchang Wang; Akihiko Terada; Susanne Lackner; Barth F. Smets; Mogens Henze; Siqing Xia; Jianfu Zhao

2009-01-01

260

Kinetic studies and performance evaluation of an anaerobic fixed-film reactor treating fuel alcohol wastewater  

SciTech Connect

This study was part of an extensive treatability study of the fuel alcohol wastewater generated at the OSU Agricultural Engineering Fuel Alcohol Research Facility. A bench-scale fixed-film upflow anaerobic reactor was operated for a period of over two years in order to collect the appropriate data for reliable design and operation of a full-scale fixed film anaerobic system. The biological kinetic constants for substrate removal, total gas production, and methane production were developed in terms of BOD{sub 5}, COD, and TOC, at two different temperatures, 36C and 25C. Shock loads studies were also performed, including organic shock loads, low temperature shocks, and shut-down (no feeding) periods. The alcohol wastewater can be easily treated using fixed-film upflow anaerobic reactor. The substrate removal characteristics were a function of the applied mass substrate loading. For applied mass substrate loading rates higher than 27 lbs BOD{sub 5} per day per 1000 sq. ft., the treatment efficiency and the gas production deteriorated, mainly due to accumulation of volatile fatty acids. The methane content of the gas decreased and the carbon dioxide content increased as the applied mass loading rates were increased up to around 12 lbs BOD{sub 5}/day/1000 sq. ft. at which point they leveled out 59% and 39%, respectively. The total gas production and the methane production were also a function of the applied mass substrate loading rate. The substrate removal kinetics and the gas kinetics were considerably different at the two temperatures. The reactor was able to successfully accommodate organic and low temperature shock loads, as well as, shut-down or no feeding periods.

Gonzalez, R.A.

1987-01-01

261

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

262

Method and apparatus for siloxane measurements in a biogas  

US Patent & Trademark Office Database

A method for monitoring of siloxane compounds in a biogas includes the step of generating a first absorption spectrum based on a ratio of a first spectral measurement and a second spectral measurement. The first spectral measurement is from a non-absorptive gas having substantially no infrared absorptions in a specified wavelength range of interest and the second spectral measurement is from a sample gas comprising the biogas. The method also includes the step of calculating a concentration of at least one siloxane compound in the biogas using a second absorption spectrum based on, at least, a first individual absorption spectrum for a known concentration of the at least one siloxane compound.

2013-06-11

263

Methane production using whole and screened dairy manure in conventional and fixed-film reactors  

SciTech Connect

The technical feasibility of adopting the fixed-film reactor concept for biogas production from screened dairy manure was investigated. The methane production capability of laboratory-scale 4-L anaerobic reactors (conventional and fixed-film) receiving screened dairy manure and operated at 35/sup 0/C was compared. Dairy manure filtrate with 4.4% total solids (TS) and 3.4% volatile solids (VS) (average value) was prepared from 1:1 manure-water slurry. The feed material was added intermittently at loading rates ranging from 2.34 to 25 and 2.25 to 785 g VS/L d, respectively, for the conventional and fixed-film reactors. Maximum methane production rate (L CH/sub 4//L d) for the conventional reactor was 0.63 L CH/sub 4//L d achieved at a 6-day hydraulic retention time (HRT). For the fixed-film reactor the maximum production rate was 3.53 L CH/sub 4//L d when operated at a loading rate of 262 g VS/L d (3 h HRT). The fixed film reactor was capable of sustaining a loading of 785 g VS/L d (1 h HRT). The fixed-film reactor performed much better than the conventional reactors. These results indicate that a large reduction of required reactor volume is possible through application of a fixed-film concept combined with a liquid-solid separation pretreatment of dairy manure.

Liao, P.H.; Lo, K.V.

1985-01-01

264

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

2013-10-15

265

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

2013-03-01

266

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

267

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

268

Prospects in straw disintegration for biogas production.  

PubMed

The pretreatment methods for enhancing biogas production from oat straw under study include hot maceration, steam explosion, and pressure shockwaves. The micropore area (9, 55, and 64 m(2) g(-1)) inhibitor formations (0, 15, and 0 mL L(-1)) as well as the overall methane yields (67, 179, and 255 CH4 VS t(-1)) were robustly analyzed. It was confirmed that the operating conditions of the steam explosion must be precisely tailored to the substrate. Furthermore, it was beneficial to prepend the hot maceration before the steam explosion and the pressure shockwaves. The second alternative may give increased methane yields (246 in comparison to 273 CH4 VS t(-1)); however, the application of pressure shockwaves still faces limitations for deployment on a commercial scale. PMID:23625121

Maroušek, Josef

2013-10-01

269

The performance of hafnium and gadolinium self powered neutron detectors in the TREAT reactor  

Microsoft Academic Search

The use of gadolinium and hafnium self powered neutron detectors in a transient reactor is described in this paper. The detectors were calibrated to the fission rate of U-235 using calibrated fission chambers; the calibration factors were tested in two reactors in steady state and found to be consistent. Calibration of the detectors in transient reactor conditions was done by

G. R. Imel; P. R. Hart

1996-01-01

270

On-Farm Animal Waste for Biogas Production in Hawaii.  

National Technical Information Service (NTIS)

The current state of knowledge and bottlenecks of animal waste management systems is reviewed briefly. The estimated biogas production potential from manures in the State of Hawaii is tabulated. Waste management systems for two pig farms in the state are ...

1980-01-01

271

BIOGAS-GASOLINE HYBRID ENGINE ??NG C? S? D?NG PH?I H?P NHIÊN LI?U BIOGAS -X?NG  

Microsoft Academic Search

A biogas-gasoline hybrid engine converted from a 2HP spark ignition engine is used in the study. The engine is supplied by gasoline at starting and idling regimes. Full power of the engine is given by biogas combustion. Engine speed is controlled automatically by a double regulator which activates the biogas valve and mixture valve simultaneously. The relationship between the motions

BUI VAN GA; MINH TIEN; TRAN HAU LUONG

2008-01-01

272

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

273

[Influencing factors for operational performance of a biofilm reactor with microbubble aeration using SPG membrane].  

PubMed

The microbubble-aerated biofilm reactor provides a feasibility to apply microbubble aeration in aerobic wastewater treatment processes. In this study, Shirasu porous glass (SPG) membranes were used for microbubble aeration in a fixed bed biofilm reactor treating synthetic municipal wastewater. The influencing factors for operational performance of the bioreactor were investigated, including operating parameters, SPG membrane fouling and its structural changes. The results indicated that there was no significant influences of air flux, organic loading rate and packed bed on COD removal and an average COD removal efficiency of 80% -90% could be achieved under different operating conditions. On the other hand, the dissolved oxygen (DO) concentrations decreased significantly along with reducing air flux or increasing organic loading rate. As a result, the ammonia removal deteriorated gradually and the average ammonia removal efficiency decreased from 80% -90% to 20% -30% At the same time, the total nitrogen (TN) removal achieved in the simultaneous nitrification and denitrification process was also reduced from 30% -40% to about 20% , due to nitrification inhibition. Higher available porosity could be obtained when ring packing was used in the fixed bed, resulting in improvement of contaminant removal performance. An oxygen utilization efficiency of close to 100% could be achieved at low air fluxes or high organic loading rates during microbubble aeration. Both biofilm growth and organic foulant accumulation on SPC, membrane surface contributed to membrane fouling after long-term operation. The average pore size and porosity of SPG membrane increased significantly due to the chemical corrosion caused by alkali NaClO solution used for online cleaning. Then the air permeation of SPG membrane was affected by membrane fouling and destroyed pore structure. PMID:25338375

Zhang, Lei; Zhang, Ming; Liu, Chun; Zhang, Jing; Liu, Jun-Liang

2014-08-01

274

[Influence of bioleaching on dewaterability of cattle biogas slurry].  

PubMed

The dewaterability of cattle biogas slurry facilitated by bioleaching was investigated through batch experiments with co-inoculation of different Acidophilic thiobacilli (Acidithiobacillus thiooxidans TS6 or Acidithiobacillus ferrooxidans LX5). The experiment was set the following 5 treatments: (1) original biogas slurry (CK), (2) 4 g x L(-1) Fe(2+) (uninoculation), (3)2 g x L(-1) S(0) + 25 mL A. t, (4) 4 g x L(-1) Fe(2+) + 25 mL A. f and (5) 2 g x L(-1) S(0) + 4 g x L(-1) Fe(2+) + 12.5 mL A. t + 12.5 mL A. f. During bioleaching, dynamic changes of pH, ORP, Fe(2+), F(3+), total Fe, the settleability, the turbidity of the supernatant after settling for 12 h, and the dewaterability (expressed as specific resistance to filtration gamma or capillary suction time, CST) of biogas slurry were monitored. Results show that specific resistance gamma and CST of bioleached biogas slurry are reduced drastically for the treatments of original biogas slurry spiked with only Fe(2+), the treatment of original biogas slurry co-spiked with Fe(2+) and Acidithiobacillus ferrooxidans LX5, and the treatment of original biogas slurry co-spiked with Fe(2+), S(0) and two Acidophilic thiobacilli. Taking the dewaterability, settleability, the turbidity of the supernatant fluid after settle 12 h and economical cost into account, the treatment of original biogas slurry co-spiked with Fe(2+) and Acidithiobacillus ferrooxidans LX5 is the most suitable pattern for cattle biogas slurry bioleaching. After bioleaching, 1.14% of organic matter, 0.09% of N, 0.05% of P, and 0.1% of K are lost in the bioleaching process, but it don't affect its fertilizer efficiency. Meanwhile, the 63.2% of Cu and 91.3% of Zn are removed from the biogas slurry, and elimination efficiencies of total coliforms in bioleached slurry exceed 99%. This study might provide a new approach for treatment and disposal of biogas slurry. PMID:22295641

Zhou, Jun; Zhou, Li-Xiang; Liu, Fen-Wu; Ren, Yun; Wang, Dian-Zhan

2011-11-01

275

Global warming mitigation potential of biogas plants in India.  

PubMed

Biogas technology, besides supplying energy and manure, provides an excellent opportunity for mitigation of greenhouse gas (GHG) emission and reducing global warming through substituting firewood for cooking, kerosene for lighting and cooking and chemical fertilizers. A study was undertaken to calculate (1) global warming mitigation potential (GMP) and thereby earning carbon credit of a family size biogas plant in India, (2) GMP of the existing and target biogas plants in the country and (3) atmospheric pollution reduction by a family size biogas plant. The GMP of a family size biogas plant was 9.7 t CO(2) equiv. year( - 1) and with the current price of US $10 t( - 1) CO(2) equiv., carbon credit of US $97 year( - 1) could be earned from such reduction in greenhouse gas emission under the clean development mechanism (CDM). A family size biogas plant substitutes 316 L of kerosene, 5,535 kg firewood and 4,400 kg cattle dung cake as fuels which will reduce emissions of NOx, SO(2), CO and volatile organic compounds to the atmosphere by 16.4, 11.3, 987.0 and 69.7 kg year( - 1), respectively. Presently 3.83 million biogas plants are operating in the country, which can mitigate global warming by 37 Mt CO(2) equiv. year( - 1). Government of India has a target of installing 12.34 million biogas plants by 2010. This target has a GMP of 120 Mt CO(2) equiv. year( - 1) and US $1,197 million as carbon credit under the CDM. However, if all the collectible cattle dung (225 Mt) produced in the country is used, 51.2 million family size biogas plants can be supported which will have a GMP of 496 Mt of CO(2) equiv. year( - 1) and can earn US $4,968 million as carbon credit. The reduction in global warming should encourage policy makers to promote biogas technology to combat climate change and integration of carbon revenues will help the farmers to develop biogas as a profitable activity. PMID:18843544

Pathak, H; Jain, N; Bhatia, A; Mohanty, S; Gupta, Navindu

2009-10-01

276

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

277

Process flow model of solid oxide fuel cell system supplied with sewage biogas  

NASA Astrophysics Data System (ADS)

A model for a 100 kW 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 (0.15 W/cm 2 at 80% fuel utilisation). Real annual data from an existing sewage plant were used as input to the model. From the input of 43 m 3/h biogas (63% CH 4), equivalent to 269 kW (higher heating value, HHV), the SOFC stack was calculated to deliver 131 kW el electricity (48.7%) using a steam-to-carbon ratio of 0.5. This would allow the sewage site to more than cover its own electrical needs, hence to depollute the waste stream at negative energy cost. In its current exploitation using a low efficient gas engine (130 kW), the site is only ?50% self-sufficient. Special attention was given to the thermal balance of the stack. The stack developed heat (143 kW) could be balanced by endothermal reforming (78 kW) and by cathode excess air ? (=3), allowing a temperature difference between stack inlet and outlet of 200 K. The case was compared to other fuel scenarios. Steam-added biogas behaves basically identically to steam-reformed methane. For partial oxidation of biogas or pure hydrogen feeding, electrical efficiency drops to under 43% while ? needs to be raised to 4.5 to maintain the 200 K thermal gradient over the stack.

Van herle, J.; Maréchal, F.; Leuenberger, S.; Membrez, Y.; Bucheli, O.; Favrat, D.

278

Modeling for anaerobic fixed-bed biofilm reactors  

Microsoft Academic Search

Biofilm models, developed by previous researchers, were incorporated with an equilibrium model to study the physical and chemical aspects of the anaerobic fixed-bed biofilm reactors. In order to investigate the mechanism of equilibrium in an anaerobic biofilm reactor, a non-equilibrium model was derived from the equilibrium model to simulate the gas transfer process involved in biogas production. The equilibrium model

Yeongming Bill

1989-01-01

279

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

280

Emergy Analysis of Biogas Systems Based on Different Raw Materials  

PubMed Central

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

2013-01-01

281

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

2013-01-01

282

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

2012-10-15

283

Performance and granulation in an upflow anaerobic sludge blanket (UASB) reactor treating saline sulfate wastewater.  

PubMed

An upflow anaerobic sludge blanket reactor was employed to treat saline sulfate wastewater. Mesophilic operation (35 ± 0.5 °C) was performed with hydraulic retention time fixed at 16 h. When the salinity was 28 g L(-1), the chemical oxygen demand and sulfate removal efficiencies were 52 and 67 %, respectively. The salinity effect on sulfate removal was less than that on organics removal. The methane productions were 887 and 329 cm(3) L(-1) corresponding to the NaCl concentrations of 12 and 28 g L(-1), respectively. High salinity could stimulate microbes to produce more extracellular polymeric substances (EPSs) and granulation could be performed better. Besides, with the high saline surroundings, a great deal of Na(+) compressed the colloidal electrical double-layer, neutralized the negative charge of the sludge particles and decreased their electrostatic repulsion. The repulsion barrier disappeared and coagulation took place. The maximum size of granules was 5 mm, which resulted from the coupled triggering forces of high EPSs and Na(+) contents. Sulfate-reducing bacteria (SRB) were dominant in the high saline surroundings while the methane-producing archaea dominated in the low saline surroundings. The SRB were affected least by the salinity. PMID:23624725

Li, Jin; Yu, Lian; Yu, Deshuang; Wang, Dan; Zhang, Peiyu; Ji, Zhongguang

2014-02-01

284

Performance of a cutinase membrane reactor for the production of biodiesel in organic media.  

PubMed

The enzymatic transesterification of oils with an alcohol, using recombinant cutinase of Fusarium solani pisi microencapsulated in sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/isooctane reversed micelles, was performed in a membrane bioreactor (MBR). A tubular ceramic membrane with a nominal molecular weight cut off of 15,000 Da was used to retain the enzyme, and characterized in terms of rejection coefficients of the reaction components by transmission experiments. The performance of the MBR in a total recirculation-batch mode was compared with results obtained in a stirred batch tank reactor. The continuous operation of the MBR was also evaluated and the influence of the alcohol type and permeate flow rate on conversion degree and productivity (up to 500 g(product) /day/g(enzyme) was attained) were analyzed. Cutinase wild type and mutant T179C were tested for this process and the high long-term operational stability of the cutinase mutant demonstrated its potential as biocatalyst for the enzymatic continuous production of biodiesel. PMID:21290382

Badenes, Sara M; Lemos, Francisco; Cabral, Joaquim M S

2011-06-01

285

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

286

Biogas from the organic fraction of municipal solid waste: Dealing with contaminants for a solid oxide fuel cell energy generator.  

PubMed

The present work investigates electricity production using a high efficiency electrochemical generator that employs as fuel a biogas from the dry anaerobic digestion of the organic fraction of municipal solid waste (OFMSW). The as-produced biogas contains several contaminants (sulfur, halogen, organic silicon and aromatic compounds) that can be harmful for the fuel cell: these were monitored via an innovative mass spectrometry technique that enables for in-line and real-time quantification. A cleaning trap with activated carbons for the removal of sulfur and other VOCs contained in the biogas was also tested and monitored by observing the different breakthrough times of studied contaminants. The electrochemical generator was a commercial Ni anode-supported planar Solid Oxide Fuel Cell (SOFC), tested for more than 300h with a simulated biogas mixture (CH4 60vol.%, CO2 40vol.%), directly fed to the anode electrode. Air was added to promote the direct internal conversion of CH4 to H2 and CO via partial oxidation (POx). The initial breakthrough of H2S from the cleaning section was also simulated and tested by adding ?1ppm(v) of sulfur in the anode feed; a full recovery of the fuel cell performance after 24h of sulfur exposure (?1ppm(v)) was observed upon its removal, indicating the reliable time of anode exposure to sulfur in case of exhausted guard bed. PMID:25081854

Papurello, Davide; Lanzini, Andrea; Leone, Pierluigi; Santarelli, Massimo; Silvestri, Silvia

2014-11-01

287

Steady-state natural circulation performance of the Experimental Breeder Reactor II primary heat transport circuit  

Microsoft Academic Search

The Experimental Breeder Reactor II is a sodium-cooled fast breeder reactor and is designed to operate at a thermal power of 62.5 MW and an electrical generation rate of 20 MW. In a continuing program devoted to the understanding of the thermal, hydraulic, and neutronic behavior of this reactor under both normal and off-normal operating conditions, a series of steady-state

R. M. Singer; J. L. Gillette; G. H. Golden; D. Mohr; W. K. Lehto; C. C. Price; J. I. Sackett

1977-01-01

288

Effect of equation of state on prediction of trickle bed reactor model performance  

E-print Network

. ~ 1 IO] I 0 2 3 4 6 6 7 8 9 IQ I I REACTOR NclOH'I IOINENSIONLEScl Figure 7. CONVERSION AS A PUNCTTON OF REACTOR HEIGHT FOR PEED RATE OF 0. 08 GMOLE/SEC 00 70 60 1 . PENG ROBINSON 2. JOFFE ZUDKEVITCH 3. SRK 4. REDLICH KWONG 5. WILSON 6.... ~ 1 IO] I 0 2 3 4 6 6 7 8 9 IQ I I REACTOR NclOH'I IOINENSIONLEScl Figure 7. CONVERSION AS A PUNCTTON OF REACTOR HEIGHT FOR PEED RATE OF 0. 08 GMOLE/SEC 00 70 60 1 . PENG ROBINSON 2. JOFFE ZUDKEVITCH 3. SRK 4. REDLICH KWONG 5. WILSON 6...

Netherland, Donald Wayne

2012-06-07

289

System Performance and Monte Carlo Analysis of Light Water Reactor Spent Fuel Assay Using Neutron Slowing Down Time Method  

Microsoft Academic Search

There is a compelling safeguards need to assay nondestructively fissile plutonium from fissile uranium in spent light water reactor fuel. Present methods suffer from a number of limitations and are incapable of providing accurate and independent safeguards assay information. The only feasible method capable of performing the required assay of spent fuel is the slowing down time (SDT) method. The

Naeem Mohamed Abdurrahman

1991-01-01

290

Mass transfer and shear in an airlift bioreactor: Using a mathematical model to improve reactor design and performance  

Microsoft Academic Search

Several studies have shown a strong relationship between morphology and agitation (Cui et al., 1997; Berzins et al., 2001). The shear stress distribution and mass transfer are the important parameters which can improve the performance of bioreactor. In this work, a mathematical model using computational fluid dynamics (CFD) techniques is used to study the gas–liquid dispersion in an airlift reactor.

R. Bannari; A. Bannari; B. Selma; P. Proulx

2011-01-01

291

Mathematical modelization of a packed-bed reactor performance with immobilized yeast for ethanol fermentation. [Saccharomyces cerevisiae  

SciTech Connect

The performance of a continuous vertical packed-bed reactor with yeast immobilized in carrageenan gel beads is reported. The study focuses on the mathematical modeling of the steady-state fermentor behavior by means of a tanks-in-series model which includes the intrinsic kinetic model and the external mass transfer and internal diffusion-reaction conditions in the beads.

Godia, F.; Casas, C.; Sola, C.

1987-01-01

292

SAFSIM: A computer program for engineering simulations of space reactor system performance  

Microsoft Academic Search

SAFSIM (System Analysis Flow SIMulator) is a FORTRAN computer program that provides engineering simulations of user-specified flow networks at the system level. It includes fluid mechanics, heat transfer, and reactor dynamics capabilities. SAFSIM provides sufficient versatility to allow the simulation of almost any flow system, from a backyard sprinkler system to a clustered nuclear reactor propulsion system. In addition to

D. Dobranich

1992-01-01

293

A computer program for engineering simulations of space reactor system performance  

Microsoft Academic Search

Nuclear thermal propulsion systems are envisioned as a fast and efficient form of transportation for the exploration of space. Several nuclear reactor concepts have been proposed. This document discusses SAFSIM (System Analysis Flow SIMulator) which is an engineering computer program that allows the fluid mechanic, heat transfer, and reactor dynamic simulation of the entire propulsion system. SAFSIM currently contains three

D. Dobranich

1992-01-01

294

The Success of Biogas Plants in Nepal: A Note on Gender  

Microsoft Academic Search

This article describes a successful programme to disseminate biogas plants in Nepal, and summarises the findings of various studies on the impact of the biogas technology on the quality of life of women.

J. Hans M. Opdam

1997-01-01

295

Performance of methanogenic reactors in temperature phased two-stage anaerobic digestion of swine wastewater.  

PubMed

The present study investigated the shifts in the chemical profiles of a two-phase anaerobic digestion system in methanogenic and acidogenic reactors for the treatment of swine wastewater. Acidogenic and methanogenic digesters were used with overall HRTs ranging from 27 to 6 d. In the optimized thermophilic/acidogenic phase throughout the entire experimental period, VS was reduced by 13.8% (1.6%); however, COD hardly decreased because of the thermophilic hydrolysis of organic materials, such as carbohydrates, proteins, and lipids, without any significant consumption of volatile fatty acids. In the methanogenic/mesophilic phase, COD was reduced by 65.8 (1.1)% compared to a 47.4 (2.9)% reduction in VS reduction efficiency with the gradual increase in methane production during a methanogenic HRT between 25 and 10 d. A high protein degradation rate was observed in the optimized acidogenic phase, which is assumed to be due to the low content of carbohydrates in raw swine wastewater as well as the readily thermophilic hydrolysis of proteins. Two-phase systems of anaerobic digestion consisting of optimized thermophilic and mesophilic methanogenic digesters showed a stable performance with respect to VS reduction efficiency with OLRs less than 3 g VS/L·d, in other words, more than 10 days of methanogenic HRT in this study. PMID:23041140

Kim, Woong; Shin, Seung Gu; Cho, Kyungjin; Lee, Changsoo; Hwang, Seokhwan

2012-12-01

296

Performance of the liquid reactivity control system in BWRs (boiling water reactors)  

SciTech Connect

Boiling water reactors rely on the injection of soluble neutron absorbers to control power in case of failure in the control rod (scram) system. Typically this liquid poison'' is injected from eight small holes on a standpipe positioned vertically near the outer edge of the core shroud in the lower plenum. The achievement of control is predicated on good mixing of this injected liquid with the coolant which is recirculating around the core upper plenum and downcomer. However, because the flows are rather low ({approximately}20% of rated with pumps tripped as expected under such conditions) and the injected solution density is much higher than that of the primary fluid, there have been concerns raised about the efficiency and completeness of this mixing. This work provides the first openly available data addressing such concerns. To avoid potentially important scaling compromises, the data were obtained from full-scale simulations. From the experiments performed so far, we can conclude that complete boron mixing (entrainment) will occur for recirculation flow rates down to 8.2% of rated. 3 refs., 60 figs., 2 tabs.

Theofanous, T.G.; Shabana, E.A. (California Univ., Santa Barbara, CA (USA). Dept. of Chemical and Nuclear Engineering)

1989-09-01

297

Biogas end-use in the European community  

SciTech Connect

In Europe over the past few years the generation of biogas for energy and environmental purposes has been gaining in importance. Industrial wastewaters, cattle manure, sewage sludges, urban wastes, crop residues, algae and aquatic biomass are all typical of the materials being utilized. In contrast to the extensive inventory of biomethanation processes which has been carried out within the EEC, until recently a detailed, up-to-date investigation of the end-sues of biogas had not been undertaken. To supply the necessary information, the Commission of the European Communities and the Belgian Science Policy Office jointly entrusted a study to the Unit of Bioengineering at the Catholic University of Louvain, Belgium. This book is record of the study and has the following key features: it gives a broad overview of the ongoing use of biogas in Europe; it summarizes available data on storage, purification and engines using biogas; it draws several conclusions concerning the technical and economic viability of the processes; it discusses the problems of using biogas; and it outlines recommendations and future R and D and demonstration projects in the field.

Constant, M.; Naveau, H.; Nyns, E.J. (Unite de Genie Biologique, Universite Catholique de Louvain (BE)); Ferrero, G.L.

1989-01-01

298

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

299

Thermal Hydraulic Analysis of an Experimental Reactor Cavity Cooling System with Water: Performance and Stability  

NASA Astrophysics Data System (ADS)

This experimental study investigated the thermal hydraulic behavior and boiling mechanisms present in a scaled reactor cavity cooling system (RCCS). The experimental facility reflects a ¼ scale model of one conceptual design for decay heat removal in advanced GenIV nuclear reactors. Radiant heaters supply up to 25 kW/m2 onto a three parallel riser tube and cooling panel test section assembly, representative of a 5° sector model of the full scale concept. Derived similarity relations have preserved the thermal hydraulic flow patterns and integral system response, ensuring relevant data and similarity among scales. Attention will first be given to the characterization of design features, form and heat losses, nominal behavior, repeatability, and data uncertainty. Then, tests performed in single-phase have evaluated the steady-state behavior. Following, the transition to saturation and subsequent boiling allowed investigations onto four parametric effects at two-phase flow and will be the primary focus area of remaining analysis. Baseline conditions at two-phase flow were defined by 15.19 kW of heated power and 80% coolant inventory, and resulted in semi-periodic system oscillations by the mechanism of hydrostatic head fluctuations. Void generation was the result of adiabatic expansion of the fluid due to a reduction in hydrostatic head pressure, a phenomena similar to flashing. At higher powers of 17.84 and 20.49 kW, this effect was augmented, creating large flow excursions that followed a smooth and sinusoidal shaped path. Stabilization can occur if the steam outflow condition incorporates a nominal restriction, as it will serve to buffer the short time scale excursions of the gas space pressure and dampen oscillations. The influences of an inlet restriction, imposed by an orifice plate, introduced subcooling boiling within the heated core and resulted in chaotic interactions among the parallel risers. The penultimate parametric examined effects of boil-off and inventory loss, where five different stages of natural circulation flow were identified: single-phase heating, transitional nucleate boiling, hydrostatic head fluctuations, stable two-phase flow, and geysering. Finally, the implementation of the model RCCS to a full scale plant was investigated by a multivariate test simulating an hypothetical accident scenario.

Lisowski, Darius D.

300

Method and apparatus for enhancing reactor air-cooling system performance  

DOEpatents

An enhanced decay heat removal system is disclosed for removing heat from the inert gas-filled gap space between the reactor vessel and the containment vessel of a liquid metal-cooled nuclear reactor. Multiple cooling ducts in flow communication with the inert gas-filled gap space are incorporated to provide multiple flow paths for the inert gas to circulate to heat exchangers which remove heat from the inert gas, thereby introducing natural convection flows in the inert gas. The inert gas in turn absorbs heat directly from the reactor vessel by natural convection heat transfer. 6 figs.

Hunsbedt, A.

1996-03-12

301

The optimal production of biogas for use as a transport fuel in Ireland  

Microsoft Academic Search

The Biofuels Directive places an onus on EU member states to ensure that biofuels are placed on their markets. This paper investigates the use of CH4-enriched biogas as a fuel. A number of options, which produce CH4-enriched biogas, were analysed from technical, economic and environmental perspectives. Biogas may be produced at a centralised anaerobic digestion (CAD) facility, accepting agricultural slurries

J. D. Murphy; K. McCarthy

2005-01-01

302

Improvement of biogas production by biotechnological manipulation of the microbial population  

Microsoft Academic Search

Biogas is a renewable energy carrier and the production of biogas is associated with double benefits: elimination of environmental pollution problems is coupled with the generation of useful energy. Biogas technologies commonly apply natural anaerobic consortia of microbes. This is partly due to the fact that, from a microbiological aspect, this is a very complicated and complex system. Moreover, the

N. Acs; Z. Bagi; G. Rakhely; E. Kovacs; R. Wirth; K. L. Kovacs

2011-01-01

303

Landfill Biogas for heating Greenhouses and providing Carbon Dioxide Supplement for Plant Growth  

Microsoft Academic Search

Present municipal solid waste landfills generate biogas and leachate. Biogas is flared on site to destroy noxious contaminants and water is extracted from leachate to be drained away. However, biogas could alternatively be a cheap fuel for winter heating and could provide horticultural greenhouses with abundant carbon dioxide to boost plant growth all year long. The paper describes how this

A Jaffrin; N Bentounes; A. M Joan; S Makhlouf

2003-01-01

304

The Biogas/Biofertilizer Business Handbook. Third Edition. Appropriate Technologies for Development. Reprint R-48.  

ERIC Educational Resources Information Center

This book describes one approach to building and operating biogas systems. The biogas systems include raw material preparation, digesters, separate gas storage tanks, use of the gas to run engines, and the use of the sludge as fertilizer. Chapters included are: (1) "Introduction"; (2) "Biogas Systems are Small Factories"; (3) "The Raw Materials of…

Arnott, Michael

305

IEA-Renewable Energy Technologies, Bioenergy Agreement Task 37: Energy from Biogas and Landfill Gas  

E-print Network

EFP-06 IEA- Renewable Energy Technologies, Bioenergy Agreement Task 37: Energy from Biogas-Bioenergy, Task 37- Energy from Biogas and Landfill Gas", via samarbejde, informationsudveksling, fælles analyser. biogas fra anaerob udrådning (AD) som en integreret gylle og affalds behandlings teknologi. Arbejdet

306

A methodology for financial evaluation of biogas technology in India using cost functions  

Microsoft Academic Search

A methodology for financial evaluation of biogas technology for domestic use in India using recently developed cost functions is reported. Analytical expressions for the unit cost of biogas and cost per unit of useful energy delivered by a biogas plant in combination with other suitable technologies have been developed. Net present value and discounted pay-back period have been calculated. The

Seemin Rubab; Tara Chandra Kandpal

1996-01-01

307

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 2.6 g VS/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 8500 mg/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 4.4 L/d and from 27.4% to 60.5%, respectively. However, inhibition of hydrolysis in acidogenic reactor was demonstrated under the OLR of 2.6 g VS/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

2013-10-01

308

Factors Affecting Process Temperature and Biogas Production in Small-scale Rural Biogas Digesters in Winter in Northern Vietnam.  

PubMed

This study investigated the main factors influencing digester temperature and methods to reduce heat losses during the cold season in the subtropics. Four composite digesters (two insulated and two uninsulated) were buried underground to measure their internal temperature (°C) at a depth of 140 cm and 180 cm, biogas production and methane (CH4) concentration in biogas from August to February. In parallel the temperature of the air (100 cm above ground), in the slurry mixing tank and in the soil (10, 100, 140, and 180 cm depth) was measured by thermocouple. The influent amount was measured daily and the influent chemical composition was measured monthly during the whole experimental period. Seasonal variations in air temperature significantly affected the temperature in the soil, mixing tank and digester. Consequently, biogas production, which is temperature dependent, was influenced by the season. The main factors determining the internal temperature in the digesters were insulation with Styrofoam, air temperature and temperature of slurry in the mixing tank. Biogas production is low due to the cold climate conditions in winter in Northern Vietnam, but the study proved that storing slurry in the mixing tank until its temperature peak at around 14:00 h will increase the temperature in the digester and thus increase potential biogas production. Algorithms are provided linking digester temperature to the temperature of slurry in the mixing tank. PMID:25050049

Pham, C H; Vu, C C; Sommer, S G; Bruun, S

2014-07-01

309

[Biogas production from cellulose-containing substrates: a review].  

PubMed

Anaerobic microbial conversion of organic substrates to various biofuels is one of the alternative energy sources attracting the greatest attention of scientists. The advantages of biogas production over other technologies are the ability of methanogenic communities to degrade a broad range of substrates and concomitant benefits: neutralization of organic waste, reduction of greenhouse gas emission, and fertilizer production. Cellulose-containing materials are a good substrate, but their full-scale utilization encounters a number of problems, including improvement of the quality and amount ofbiogas produced and maintenance of the stability and high efficiency of microbial communities. We review data on microorganisms that form methanogenic cellulolytic communities, enzyme complexes of anaerobes essential for cellulose fiber degradation, and feedstock pretreatment, as biodegradation is hindered in the presence of lignin. Methods for improving biogas production by optimization of microbial growth conditions are considered on the examples of biogas formation from various types of plant and paper materials: writing paper and cardboard. PMID:23101383

Tsavkelova, E A; Netrusov, A I

2012-01-01

310

Biogas as a resource-efficient vehicle fuel.  

PubMed

There are currently strong incentives for increased use of renewable fuels in the transport sector worldwide. However, some bioethanol and biodiesel production routes have limitations with regard to resource efficiency and reduction of greenhouse gases. More efficient biofuel systems are those based on lignocelluloses and novel conversion technologies. A complementary strategy to these is to increase the production of biogas from the digestion of organic residues and energy crops, or from byproducts of ethanol and biodiesel production. Compared with other biomass-based vehicle fuels available so far, biogas often has several advantages from an environmental and resource-efficiency perspective. This provides the motivation for further technological development aiming to reduce costs and thereby increased economic competitiveness of biogas as a vehicle fuel. PMID:18036686

Börjesson, Pål; Mattiasson, Bo

2008-01-01

311

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. PMID:16595023

Bertin, Lorenzo; Colao, Maria Chiara; Ruzzi, Maurizio; Marchetti, Leonardo; Fava, Fabio

2006-01-01

312

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

313

Hydrogen in biogas and its impact to the atmosphere  

NASA Astrophysics Data System (ADS)

The shortage and increase in cost of fossil fuels leads to an increased interest in renewable energy sources. One important renewable energy source is biogas, produced by fermentation of organic material. During the last ten years the number of biogas plants has continuously increased and it is expected to increase further. Biogas is a mixture of mainly methane and carbon dioxide but contains also molecular hydrogen (H2). The hydrogen content of biogas depends on the used substrate and the production process. Hydrogen is also produced by conversion of biogas. Although hydrogen is considered as one of the most important future energy carriers, little is known about the global biogeochemical cycle of this trace gas (Rhee et al. 2006) and its impact to the atmosphere is discussed controversially. In order to assess the impact of an expected increasing H2 concentration to the atmosphere a fundamental understanding of the sources and sinks of the global H2 cycle is indispensable (Tromp et al. 2003, Warwick et al. 2004). Due to the large mass difference between hydrogen and deuterium the isotope composition is one possibility to obtain further information about the sources and sinks. Here we will present first results of the isotope composition of hydrogen in biogas. Literature Rhee, T.S., C.A.M. Brenninkmeijer, and T. Röckmann; The overwhelming role of soils in the global atmospheric hydrogen cycle, Atmos. Chem. Phys., 6, 1611-1625, 2006. Tromp, T.K., Shi, R.-L., Allen, M., Eiler, J.M., and Y. L. Yung1; Potential Environmental Impact of a Hydrogen Economy on the Stratosphere, Science, 300, 1740-1742, 2003. Warwick, N.J., Bekki, S., Nisbet, E.G., and J.A. Pyle; Impact of a hydrogen economy on the stratosphere and troposphere studied in a 2-D model; Geo.Res.Lett., 31, L05107, doi:10.1029/2003GL019224, 2004.

Walter, S.; Laukenmann, S.; Stams, A. J. M.; Röckmann, T.

2009-04-01

314

Metaproteome analysis of the microbial communities in agricultural biogas plants.  

PubMed

In biogas plants agricultural waste and energy crops are converted by complex microbial communities to methane for the production of renewable energy. In Germany, this process is widely applied namely in context of agricultural production systems. However, process disturbances, are one of the major causes for economic losses. In addition, the conversion of biomass, in particular of cellulose, is in most cases incomplete and, hence, insufficient. Besides technical aspects, a more profound characterization concerning the functionality of the microbial communities involved would strongly support the improvement of yield and stability in biogas production. To monitor these communities on the functional level, metaproteome analysis was applied in this study to full-scale agricultural biogas plants. Proteins were extracted directly from sludge for separation by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and subsequent identification with mass spectrometry. Protein profiles obtained with SDS-PAGE were specific for different biogas plants and often stable for several months. Differences of protein profiles were visualized by clustering, which allowed not only the discrimination between mesophilic and thermophilic operated biogas plants but also the detection of process disturbances such as acidification. In particular, acidification of a biogas plant was detected in advance by disappearance of major bands in SDS-PAGE. Identification of proteins from SDS-PAGE gels revealed that methyl CoM reductase, which is responsible for the release of methane during methanogenesis, from the order Methanosarcinales was significantly decreased. Hence, it is assumed that this enzyme might be a promising candidate to serve as a predictive biomarker for acidification. PMID:23369865

Heyer, R; Kohrs, F; Benndorf, D; Rapp, E; Kausmann, R; Heiermann, M; Klocke, M; Reichl, U

2013-09-25

315

Optimization of process performance in a granule-based anaerobic ammonium oxidation (anammox) upflow anaerobic sludge blanket (UASB) reactor.  

PubMed

In this study, the individual and interactive effects of influent substrate concentration (TNinf), hydraulic retention time (HRT) and upflow velocity (Vup) on the performance of anaerobic ammonium oxidation (anammox) in a granule-based upflow anaerobic sludge blanket (UASB) reactor were investigated by employing response surface methodology (RSM) with a central composite design. The purpose of this work was to identify the optimal combination of TNinf, HRT and Vup with respect to the nitrogen removal efficiency (NRE) and nitrogen removal rate (NRR). The reduced cubic models developed for the responses indicated that the optimal conditions corresponded to a TNinf content of 644-728mgNL(-1), an HRT of 0.90-1.25h, and a Vup of 0.60-1.79mh(-1). The results of confirmation trials were similar to the predictions of the developed models. These results provide useful information for improving the nitrogen removal performance of the anammox process in a UASB reactor. PMID:25156877

Xing, Bao-Shan; Guo, Qiong; Zhang, Zheng-Zhe; Zhang, Jue; Wang, Hui-Zhong; Jin, Ren-Cun

2014-10-01

316

Study of performances, stability and microbial characterization of a Sequencing Batch Biofilter Granular Reactor working at low recirculation flow.  

PubMed

The Sequencing Batch Biofilter Granular Reactor (SBBGR) is a promising wastewater treatment technology characterized by high biomass concentration in the system, good depuration performance and low sludge production. Its main drawback is the high energy consumption required for wastewater recirculation through the reactor bed to ensure both shear stress and oxygen supply. Therefore, the effect of low recirculation flow on the long-term (38 months) performance of a laboratory scale SBBGR was studied. Both the microbial components of the granules, and their main metabolic activities were evaluated (heterotrophic oxidation, nitrification, denitrification, fermentation, sulphate reduction and methanogenesis). The results indicate that despite reduced recirculation, the SBBGR system maintained many of its advantageous characteristics. PMID:23313178

De Sanctis, Marco; Beccari, Mario; Di Iaconi, Claudio; Majone, Mauro; Rossetti, Simona; Tandoi, Valter

2013-02-01

317

End-of-life irradiation performance of core structural components in the Shippingport Light Water Breeder Reactor  

SciTech Connect

Nondestructive and destructive end-of-life examinations of Light Water Breeder Reactor (LWBR) core structural components were performed following operation in the Shippingport Atomic Power Station for 29,047 effective full power hours. The Shippingport LWBR demonstrated that breeding can be achieved in a light water reactor with thorium and uranium-233 oxide fuel pellets contained in Zircaloy-4 tubes. The purpose of this presentation is to report results of LWBR core structural component examinations that were carried out to assess the effects of irradiation on support structure and to provide a data base for the evaluation of design procedures. The postirradiation nondestructive examinations included visual inspection and, in some cases, dye penetrant testing to assess structural integrity and surface conditions of the components. Destructive metallography was performed to assess cracking, corrosion buildup, and microstructural condition.

Clayton, J.C.; Smith, B.C.

1991-12-31

318

The impact of ENDF\\/BV fission spectrum parameter uncertainty on the prediction of fast reactor burnup performance  

Microsoft Academic Search

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)

T. J. Downar; J. Broda; J. Kritzer

1990-01-01

319

Theory and performance of the fast-running multidimensional pressurized water reactor kinetics code, SPNOVA-K  

Microsoft Academic Search

A superfast multidimensional, and compact pressurized water reactor nodal code, SUPER-NOVA (SPNOVA), which is much faster than conventional nodal codes and is very accurate, has been developed. A kinetics version of this code, SPNOVA-K, is now developed for applications to three-dimensional core kinetics analysis. The theory involved in the kinetics generalization of SPNOVA is discussed and the performance of SPNOVA-K

Y. A. Chao; P. Huang

1989-01-01

320

The performance of hafnium and gadolinium self powered neutron detectors in the TREAT reactor  

NASA Astrophysics Data System (ADS)

The use of gadolinium and hafnium self powered neutron detectors in a transient reactor is described in this paper. The detectors were calibrated to the fission rate of U-235 using calibrated fission chambers; the calibration factors were tested in two reactors in steady state and found to be consistent. Calibration of the detectors in transient reactor conditions was done by using uranium wires that were analyzed by radiochemistry techniques to determine total fissions during the transient. This was correlated to the time-integrated current of the detectors during the transient. A temperature correction factor was derived to account for self-shielding effects in the hafnium and gadolinium detectors. The dynamic response of the detectors under transient conditions was studied, and found to be excellent.

Imel, G. R.; Hart, P. R.

1996-05-01

321

The performance of ENDF/B-V. 2 nuclear data for fast reactor calculations  

SciTech Connect

Calculations with ENDF/B-V.2 data have been made for twenty-five fast-spectrum integral assemblies covering a wide range of sizes and compositions. Analysis was done by transport codes with refined cross section processing methods and detailed reactor modelling. The predictions of fission rate distributions and control rod worths were emphasized for the more prototypic benchmark cores. The results show considerable improvements in agreement with experiment compared with analysis using ENDF/B-IV data, but it is apparent that significant errors remain for fast reactor design calculations.

Atkinson, C.A.; Collins, P.J.

1987-01-01

322

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

323

Optimization of biogas production using MEMS based near infrared inline-sensor  

NASA Astrophysics Data System (ADS)

Due to climate protection and increasing oil prices, renewable energy is becoming extremely important. Anaerobic digestion is a particular environmental and resource-saving way of heat and power production in biogas plants. These plants can be operated decentralized and independent of weather conditions and allow peak load operation. To maximize energy production, plants should be operated at a high efficiency. That means the entire installed power production capacity (e.g. CHP) and biogas production have to be used. However, current plant utilization in many areas is significantly lower, which is economically and environmentally inefficient, since the biochemical process responds to fluctuations in boundary conditions, e.g. mixing in the conditions and substrate composition. At present only a few easily accessible parameters such as fill level, flow rates and temperature are determined on-line. Monitoring of substrate composition occurs only sporadically with the help of laboratory methods. Direct acquisition of substrate composition combined with a smart control and regulation concept enables significant improvement in plant efficiency. This requires a compact, reliable and cost-efficient sensor. It is for this reason that a MEMS sensor system based on NIR spectroscopy has been developed. Requirements are high accuracy, which is the basic condition for exact chemometric evaluation of the sample as well as optimized MEMS design and packaging in order to work in poor environmental conditions. Another issue is sample presentation, which needs an exact adopted optical-mechanical system. In this paper, the development and application of a MEMS-based analyzer for biogas plants will be explained. The above mentioned problems and challenges will be discussed. Measurement results will be shown to demonstrate its performance.

Saupe, Ray; Seider, Thomas; Stock, Volker; Kujawski, Olaf; Otto, Thomas; Gessner, Thomas

2013-03-01

324

Energy use of biogas hampered by the presence of siloxanes  

Microsoft Academic Search

Siloxanes are widely used in industrial processes and consumer products. Some of them reach the wastewater. Siloxanes are not decomposed in the activated sludge process and partly concentrate in the sludge. During anaerobic digestion of the sludge, they volatilise into the formed biogas. Combustion of silicon containing gases, e.g., when producing electricity, produces, however, the abrasive microcrystalline silica that has

Raf Dewil; Lise Appels; Jan Baeyens

2006-01-01

325

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

326

The effect of shock loads on the performance of an anaerobic baffled reactor (ABR). 1. Step changes in feed concentration at constant retention time  

Microsoft Academic Search

A 10-litre anaerobic baffled reactor (ABR), with eight compartments, was used to examine the effect of organic shock loads, in the form of a step change in the feed chemical oxygen demand (COD) at constant hydraulic retention time (HRT), on reactor performance in terms of COD removal, and to obtain a greater insight into microbial responses and interactions during these

Suyanee Nachaiyasit; David C. Stuckey

1997-01-01

327

Predicting the packed-bed reactor performance with immobilized microbial lactase  

Microsoft Academic Search

A mathematical model for several working conditions was numerically solved to study a fixed bed reactor with a biocatalyst. The effect of bed swelling, mass transfer limitations, axial dispersion, residence times and inlet lactose concentration were studied. A Michaelis–Menten kinetics with competitive product inhibition was used to represent the enzymatic reaction of the lactose hydrolysis by the ?-galactosidase. Lactose conversion

Enrique J. Mammarella; Amelia C. Rubiolo

2006-01-01

328

Performance of Microlith Based Catalytic Reactors for an Isooctane Reforming System  

Microsoft Academic Search

Use of catalytically coated short contact time (SCT) design approaches for application in mass transfer controlled reactors such as Auto Thermal Reformers (ATR's) is an area of much recent interest. Precision Combustion, Inc. (PCI) has developed an efficient and compact ATR using ultra-short channel length, high cell density SCT substrates (Microlith ® ). PCI has also extended this Microlith technology

Marco Castaldi; Maxim Lyubovsky; Rene LaPierre; William C. Pfefferle; Subir Roychoudhury

2003-01-01

329

Performance of the liquid reactivity control system in BWRs (boiling water reactors)  

Microsoft Academic Search

Boiling water reactors rely on the injection of soluble neutron absorbers to control power in case of failure in the control rod (scram) system. Typically this liquid poison'' is injected from eight small holes on a standpipe positioned vertically near the outer edge of the core shroud in the lower plenum. The achievement of control is predicated on good mixing

T. G. Theofanous; E. A. Shabana

1989-01-01

330

New developments in sensitivity theory: Sensitivity and uncertainty analysis of reactor performance parameters  

Microsoft Academic Search

This chapter examines additional developments necessary for the uncertainty analysis methodology to be applicable for the wide range of problems encountered in the design and analysis of nuclear reactors. Discusses improvements and refinements of the present machinery, and extensions of the sensitivity and uncertainty analysis methodologies to new domains. Attempts to lay the foundations of the sensitivity theory basis for

Greenspan

1982-01-01

331

Anaerobic treatment of palm oil mill effluent using combined high-rate anaerobic reactors.  

PubMed

Combined system of high-rate anaerobic reactors for treating palm oil mill effluent (POME) was developed and investigated in this study. The system composed of one common primary hybrid reactor which was shared by two different secondary filter reactors. An overall COD removal efficiency of 93.5% was achieved in both systems. The secondary reactors contributed not only in enhancing the COD removal efficiency, but also ensured the performance stability of the entire system. Biomass remained intact in the secondary reactor in contrast to the primary reactor in which occasional washout of biomass was observed. The pH of POME was adjusted at the beginning of the operation, as the process continued POME did not require the external pH adjustment as the pH was maintained in desired range. The biogas was produced up to 110 l/d with the yield of 0.171-0.269 l [CH?]/g [COD removed] and 59.5-78.2% content of methane. PMID:23489567

Choi, Won-Ho; Shin, Chang-Ha; Son, Sung-Min; Ghorpade, Praveen A; Kim, Jeong-Joo; Park, Joo-Yang

2013-08-01

332

Increasing biogas yield of rural biogas digester by addition of NH/sub 4/HCO/sub 3/  

SciTech Connect

By addition of 0.3% NH/sub 4/HCO/sub 3/ 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 m/sup 3//m/sup 3//d) and the fertility of NH/sub 4/HCO/sub 3/ did not decrease because of biogas fermentation. Many digesters have been built in China. But, owing to the problems of improper management, unsuitable influent mixing, etc., neither digesters nor feedstock were fully utilized. In order to solve these problems, adding NH/sub 4/HCO/sub 3/ into digester instead of animal manure was tried. Its results showed that the suitable C/N ratio of influent mixing was obtained, the fertility of effluent went up, and biogas producing rate increased. The concentration of NH/sub 4/HCO/sub 3/ is 0.2-0.6%, but the optimal is 0.3%.

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

1983-12-01

333

KUGEL: a thermal, hydraulic, fuel performance, and gaseous fission product release code for pebble bed reactor core analysis  

SciTech Connect

The KUGEL computer code is designed to perform thermal/hydraulic analysis and coated-fuel particle performance calculations for axisymmetric pebble bed reactor (PBR) cores. This computer code was developed as part of a Department of Energy (DOE)-funded study designed to verify the published core performance data on PBRs. The KUGEL code is designed to interface directly with the 2DB code, a two-dimensional neutron diffusion code, to obtain distributions of thermal power, fission rate, fuel burnup, and fast neutron fluence, which are needed for thermal/hydraulic and fuel performance calculations. The code is variably dimensioned so that problem size can be easily varied. An interpolation routine allows variable mesh size to be used between the 2DB output and the two-dimensional thermal/hydraulic calculations.

Shamasundar, B.I.; Fehrenbach, M.E.

1981-05-01

334

Effects of bed materials on the performance of an anaerobic sequencing batch biofilm reactor treating domestic sewage.  

PubMed

The objective of this study was to determine the best performance of an anaerobic sequencing batch biofilm reactor (AnSBBR) based on the use of four different bed materials as support for biomass immobilization. The bed materials utilized were polyurethane foam (PU), vegetal carbon (VC), synthetic pumice (SP), and recycled low-density polyethylene (PE). The AnSBBR, with a total volume of 7.2L, was operated in 8-h batch cycles over 10 months, and fed with domestic sewage with an average influent chemical oxygen demand (COD) of 358+/-110 mg/L. The average effluent COD values were 121+/-31, 208+/-54, 233+/-52, and 227+/-51 mg/L, for PU, VC, SP, and PE, respectively. A modified first-order kinetic model was adjusted to temporal profiles of COD during a batch cycle, and the apparent kinetic constants were 0.52+/-0.05, 0.37+/-0.05, 0.80+/-0.04, and 0.30+/-0.02 h(-1) for PU, VC, SP, and PE, respectively. Specific substrate utilization rates of 1.08, 0.11, and 0.86 mg COD/mg VS day were obtained for PU, VC, and PE, respectively. Although SP yielded the highest kinetic coefficient, PU was considered the best support, since SP presented loss of chemical constituents during the reactor's operational phase. In addition, findings on the microbial community were associated with the reactor's performance data. Although PE did not show a satisfactory performance, an interesting microbial diversity was found on its surface. Based on the morphology and denaturing gradient gel electrophoresis (DGGE) results, PE showed the best capacity for promoting the attachment of methanogenic organisms, and is therefore a material that merits further analysis. PU was considered the most suitable material showing the best performance in terms of efficiency of solids and COD removal. PMID:17765390

Garcia, M L; Lapa, K R; Foresti, E; Zaiat, M

2008-09-01

335

An evaluation of variables affecting the stability and performance of down-flow anaerobic fixed bed reactors treating piggery wastewater.  

PubMed

The influence of the most important variables on the stability and performance of down-flow anaerobic fixed bed reactors treating piggery wastewater after primary sedimentation was evaluated at HRT in the range of 1-6 d and influent substrate concentration in the range of 2 to 12 g TCOD l(-1). The effect of HRT was more pronounced compared to that of influent strength. An increase in the HRT increased the process stability and process performance at different influent strengths. TCOD, SCOD, BOD5 TSS, organic nitrogen (N) and Orthophosphate (P) removals increased with the HRT, independently of the initial substrate concentration (S0). The increase in S0 brought about an increase in the attached biomass concentration (X) at the end of the experiment. Two empirical models based on the individual effect of HRT, X and S0 were evaluated and found to be adequate to describe the influence of these variables on the process performance. The first model took all the above-mentioned variables into consideration while the second model was simplified and based on the use of HRT as the only independent variable. The results obtained by using both models were found to be similar. This demonstrated that independently of the characteristics of the operation, the behaviour and performance of the reactors were comparable. The methane yield coefficient was found to be 0.3371 methane g(-1) TCOD removed. PMID:16457178

Sánchez, E; Borja, R; Travieso, L; Martín, A; Colmenarejo, M F; Nikolaeva, S

2006-01-01

336

Comprehensive Vibration Assessment Program (CAP) performed Yonggwang Nuclear Power Plant Unit 4 (YGN 4) order verify structural integrity reactor internals flow induced vibrations prior commercial operation.  

EPA Pesticide Factsheets

Search instead for Comprehensive Vibration Assessment Program (CAP) performed Yonggwang Nuclear Power Plant Unit 4 (YGN 4) order verify structural integrity reactor internals flow induced vibrations prior commercial operation. ?

337

Packed-bed reactor performance with immobilized lactase under thermal inactivation  

Microsoft Academic Search

Thermal inactivation of immobilized lactase has been studied in the presence of substrate and products. Modulation factors of thermal inactivation have been determined for lactose and galactose based on a two-stage series-type mechanism of inactivation. Galactose was a positive modulator of enzyme stability while the opposite occurred with lactose; the glucose effect was negligible. A model for packed-bed continuous reactor

A. Illanes; C. Altamirano; A. Aillapán; G. Tomasello; M. E. Zuñiga

1998-01-01

338

Evaluation of models for the prediction of fluidized-bed reactor performance  

E-print Network

mathemat1cal models realting flu1dized-bed operat1ng characteristics (bubble diameter, jet penetration, reactant gas conversion) to various flu1dized bed designs (distributor plate des1gn, bed diameter, bed height, gas velocity, etc. ) were evaluated... e V11 V111 X111 10 12 l2 TABLE OF CONTENTS (Continued) General Nature of Bubbles Bubble Diameter Correlations and Experimental Data F'luidized-Bed Chemical Reactor Models Davidson and Harrison Model Kunii and Levenspiel 'Bubbling Bed...

Frederick, John Michael

2012-06-07

339

Comparison of rod- versus filament-type methanogenic granules: microbial population and reactor performance  

Microsoft Academic Search

Two types of methanogenic granules capable of high chemical oxygen demand removal rates were developed in laboratory-scale upflow reactors at 35° C. One granule type (R-granules) had a rod-type Methanothrix-like species as the predominant species whereas the other (F-granules) had a filament-type M. soehngenii-like acetate-utilizer as the predominant species. These two types of granules were compared in terms of operational

Wei-Min Wu; Jiirgen H. Thiele; Mahendra K. Jain; H. Stuart Pankratz; Robert F. Hickey; J. Gregory Zeikus

1993-01-01

340

Biomass retention and performance of anaerobic fixed-film reactors treating acetic acid wastewater  

Microsoft Academic Search

An acetic-acid-based synthetic wastewater of different organic concentrations was successfully treated at 35 degrees C in anaerobic downflow fixed-film reactors operated at high organic loading rates and short hydraulic retention times (HRTs). Substrate removal and methane production rates close to theoretical values of complete volumetric chemical oxygen demand (COD) removal and maximum methane conversion were obtained. A high concentration of

M. F. Hamoda; K. J. Kennedy

1987-01-01

341

Mechanical Performance of Ferritic Martensitic Steels for High Dose Applications in Advanced Nuclear Reactors  

NASA Astrophysics Data System (ADS)

Ferritic/martensitic (F/M) steels are considered for core applications and pressure vessels in Generation IV reactors as well as first walls and blankets for fusion reactors. There are significant scientific data on testing and industrial experience in making this class of alloys worldwide. This experience makes F/M steels an attractive candidate. In this article, tensile behavior, fracture toughness and impact property, and creep behavior of the F/M steels under neutron irradiations to high doses with a focus on high Cr content (8 to 12) are reviewed. Tensile properties are very sensitive to irradiation temperature. Increase in yield and tensile strength (hardening) is accompanied with a loss of ductility and starts at very low doses under irradiation. The degradation of mechanical properties is most pronounced at <0.3 T M ( T M is melting temperature) and up to 10 dpa (displacement per atom). Ferritic/martensitic steels exhibit a high fracture toughness after irradiation at all temperatures even below 673 K (400 °C), except when tested at room temperature after irradiations below 673 K (400 °C), which shows a significant reduction in fracture toughness. Creep studies showed that for the range of expected stresses in a reactor environment, the stress exponent is expected to be approximately one and the steady state creep rate in the absence of swelling is usually better than austenitic stainless steels both in terms of the creep rate and the temperature sensitivity of creep. In short, F/M steels show excellent promise for high dose applications in nuclear reactors.

Anderoglu, Osman; Byun, Thak Sang; Toloczko, Mychailo; Maloy, Stuart A.

2013-01-01

342

Exergy & economic analysis of biogas fueled solid oxide fuel cell systems  

NASA Astrophysics Data System (ADS)

We present an exergy and an economic analysis of a power plant that uses biogas produced from a thermophilic anaerobic digester (AD) to fuel a solid oxide fuel cell (SOFC). We performed a 4-variable parametric analysis of the AD-SOFC system in order to determine the optimal design operation conditions, depending on the objective function of interest. We present results on the exergy efficiency (%), power normalized capital cost ($ kW-1), and the internal rate of return on investment, IRR, (% yr-1) as a function of the current density, the stack pressure, the fuel utilization, and the total air stoichiometric ratio. To the authors' knowledge, this is the first AD-SOFC paper to include the cost of the AD when conducting economic optimization of the AD-SOFC plant. Our calculations show that adding a new AD-SOFC system to an existing waste water treatment (WWT) plant could yield positives values of IRR at today's average electricity prices and could significantly out-compete other options for using biogas to generate electricity. AD-SOFC systems could likely convert WWT plants into net generators of electricity rather than net consumers of electricity while generating economically viable rates of return on investment if the costs of SOFC systems are within a factor of two of the DOE/SECA cost targets.

Siefert, Nicholas S.; Litster, Shawn

2014-12-01

343

Biogas production from N-methylmorpholine-N-oxide (NMMO) pretreated forest residues.  

PubMed

Lignocellulosic biomass represents a great potential for biogas production. However, a suitable pretreatment is needed to improve their digestibility. This study investigates the effects of an organic solvent, N-Methylmorpholine-N-oxide (NMMO) at temperatures of 120 and 90 °C, NMMO concentrations of 75 and 85% and treatment times of 3 and 15 h on the methane yield. The long-term effects of the treatment were determined by a semicontinuous experiment. The best results were obtained using 75% NMMO at 120 °C for 15 h, resulting in 141% increase in the methane production. These conditions led to a decrease by 9% and an increase by 8% in the lignin and in the carbohydrate content, respectively. During the continuous digestion experiments, a specific biogas production rate of 92 NmL/gVS/day was achieved while the corresponding rate from the untreated sample was 53 NmL/gVS/day. The operation conditions were set at 4.4 gVS/L/day organic loading rate (OLR) and hydraulic retention time (HRT) of 20 days in both cases. NMMO pretreatment has substantially improved the digestibility of forest residues. The present study shows the possibilities of this pretreatment method; however, an economic and technical assessment of its industrial use needs to be performed in the future. PMID:24474331

Aslanzadeh, Solmaz; Berg, Andreas; Taherzadeh, Mohammad J; Sárvári Horváth, Ilona

2014-03-01

344

Performance of staged and non-staged up-flow anaerobic sludge bed (USSB and UASB) reactors treating low strength complex wastewater.  

PubMed

The use of anaerobic processes to treat low-strength wastewater has been increasing in recent years due to their favourable performance-costs balance. For optimal results, it is necessary to identify reactor configurations that are best suited for this kind of application. This paper reports on the comparative study carried out with two high-rate anaerobic reactor systems with the objective of evaluating their performances when used for the treatment of low-strength, complex wastewater. One of the systems is the commonly used up-flow anaerobic sludge blanket (UASB) reactor. The other is the up-flow staged sludge bed (USSB) system in which the reactor was divided longitudinally into 3, 5 and 7 compartments by the use of baffles. The reactors (9 l) were fed with a synthetic, soluble and colloidal waste (chemical oxygen demand (COD) < 1000 mg/l) and operated at 28 degrees C and 24 h hydraulic retention time. Intermediate flow hydraulics, between plug-flow and completely-mixed, in the UASB and 7 stages USSB reactors allowed efficient degradation of substrates with minimum effluent concentrations. Low number of compartments in the USSB reactors increased the levels of short-circuiting thus reducing substrate removal efficiencies. All reactors showed high COD removal efficiencies (93-98%) and thus can be regarded as suitable for the treatment of low strength, complex wastewater. Staged anaerobic reactors can be a good alternative for this kind of application provided they are fitted with a large enough (> or =7) number of compartments to fully take advantage of their strengths. Scale factors seem to have influenced importantly on the comparison between one and multi staged sludge-bed reactors and, therefore, observations made here could change at larger reactor volumes. PMID:20174990

Sevilla-Espinosa, Susana; Solórzano-Campo, Maricela; Bello-Mendoza, Ricardo

2010-09-01

345

Effects of solid-phase mass transfer on the performance of a stirred anaerobic sequencing batch reactor containing immobilized biomass.  

PubMed

This work reports on experiments for an anaerobic sequencing batch reactor containing immobilized biomass which aimed at verifying the effects of solid-phase mass transfer on the reactor's overall performance. Four experiments were carried out at 30 degrees C with cubic polyurethane foam particles previously inoculated with anaerobic biomass. Different solid-phase mass transfer conditions were reached in each experiment by varying the size of the bioparticle from 0.5 to 3.0 cm. The reactor was fed with a low-strength synthetic wastewater containing protein, carbohydrates and lipid and the effects of mass transfer were evaluated through dynamic substrate concentration profiles during 8-hour batch cycles. A modified first-order kinetic model provided a good representation of the behavior of the dynamic concentration profiles. The solid-phase mass transfer was found to slightly affect the concentration of effluent organic matter expressed as chemical oxygen demand (COD). The concentration of residual effluent substrate increased as the size of the bioparticle was increased. The cycle time was not affected as the size of the bioparticle was increased from 0.5 to 2.0 cm. However, it was found that the cycle time in a reactor with 3.0-cm cubic particles should be higher than that required in systems with smaller particles. The apparent first-order kinetic parameter was estimated as 0.59+/-0.01 h(-1) for experiments with bioparticle sizes ranging from 0.5 to 2.0 cm, while a value of 0.48 h(-1) was obtained in the experiment with 3.0-cm bioparticles. PMID:16843658

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

2007-05-01

346

Performance of fast reactor mixed-oxide fuels pins during extended overpower transients  

SciTech Connect

The Operational Reliability Testing (ORT) program, a collaborative effort between the US Department of Energy and the Power Reactor and Nuclear Fuel Development Corp. (PNC) of Japan, was initiated in 1982 to investigate the behavior of mixed-oxide fuel pin under various slow-ramp transient and duty-cycle conditions. In the first phase of the program, a series of four extended overpower transient tests, with severity sufficient to challenge the pin cladding integrity, was conducted. The objectives of the designated TOPI-1A through -1D tests were to establish the cladding breaching threshold and mechanisms, and investigate the thermal and mechanical effects of the transient on pin behavior. The tests were conducted in EBR-2, a normally steady-state reactor. The modes of transient operation in EBR-2 were described in a previous paper. Two ramp rates, 0.1%/s and 10%/s, were selected to provide a comparison of ramp-rate effects on fuel behavior. The test pins chosen for the series covered a range of design and pre-test irradiation parameters. In the first test (1A), all pins maintained their cladding integrity during the 0.1%/s ramp to 60% peak overpower. Fuel pins with aggressive designs, i.e., high fuel- smear density and/or thin cladding, were, therefore, included in the follow-up 1B and 1C tests to enhance the likelihood of achieving cladding breaching. In the meantime, a higher pin overpower capability, to greater than 100%, was established by increasing the reactor power limit from 62.5 to 75 MWt. In this paper, the significant results of the 1B and 1C tests are presented. 4 refs., 5 figs., 1 tab.

Tsai, H.; Neimark, L.A. (Argonne National Lab., IL (USA)); Asaga, T.; Shikakura, S. (Power Reactor and Nuclear Fuel Development Corp., Tokyo (Japan))

1991-02-01

347

Monitoring of sulfur dioxide emission resulting from biogas utilization on commercial pig farms in Taiwan.  

PubMed

The objective of this work tends to promote methane content in biogas and evaluate sulfur dioxide emission from direct biogas combustion without desulfurization. Analytical results of biogas combustion showed that combustion of un-desulfurized biogas exhausted more than 92 % of SO2 (P?biogas (P?biogas before any applications. PMID:25404540

Su, Jung-Jeng; Chen, Yen-Jung

2015-01-01

348

Anaerobic digestion of pineapple pulp and peel in a plug-flow reactor.  

PubMed

The objective of this research was to study the production of biogas by using pineapple pulp and peel, the by-products from fruit processing plants, in a plug-flow reactor (17.5 L total volume). The effects of feed concentration, total solids (TS) and hydraulic retention time (HRT) on degradation of the waste were investigated. The increase of pineapple pulp and peel of 2% (wt/vol) at HRT 7 d to 4% (wt/vol) at HRT 10 d showed increases in biogas production rate, biogas yield and methane yield - from 0.12 v/v-d, 0.26 m(3)/kg COD removed and 0.11 m(3)/kg COD removed, with COD removal at 64.1%, to 0.25 v/v-d, 0.43 m(3)/kg COD removed and 0.14 m(3)/kg COD removed, with COD removal at 60.41%. The methanogenic fermentation was more active in the middle and final parts of the reactor. The recirculation of fermentation effluent at 40% (vol/vol) of the working volume into the reactor could increase the biogas production rate and biogas yield up to 52% and 12%, respectively. The results showed technological potential for waste treatment of pineapple pulp and peel in a plug-flow reactor. PMID:22705859

Namsree, Pimjai; Suvajittanont, Worakrit; Puttanlek, Chureerat; Uttapap, Dudsadee; Rungsardthong, Vilai

2012-11-15

349

Syntrophic acetate oxidation in industrial CSTR biogas digesters.  

PubMed

The extent of syntrophic acetate oxidation (SAO) and the levels of known SAO bacteria and acetate- and hydrogen-consuming methanogens were determined in sludge from 13 commercial biogas production plants. Results from these measurements were statistically related to the prevailing operating conditions, through partial least squares (PLS) analysis. This revealed that high abundance of microorganisms involved in SAO was positively correlated with relatively low abundance of aceticlastic methanogens and high concentrations of free ammonia (>160 mg/L) and volatile fatty acids (VFA). Temperature was identified as another influencing factor for the population structure of the syntrophic acetate oxidising bacteria (SAOB). Overall, there was a high abundance of SAOB in the different digesters despite differences in their operating parameters, indicating that SAOB are an enduring and important component of biogas-producing consortia. PMID:24333792

Sun, Li; Müller, Bettina; Westerholm, Maria; Schnürer, Anna

2014-02-10

350

Green energy from marine algae: biogas production and composition from the anaerobic digestion of Irish seaweed species.  

PubMed

Marine algae have emerged as an alternative feedstock for the production of a number of renewable fuels, including biogas. In addition to energy potential, other characteristics make them attractive as an energy source, including their ability to absorb carbon dioxide (CO2), higher productivity rates than land-based crops and the lack of water use or land competition. For Ireland, biofuels from marine algae can play an important role by reducing imports of fossil fuels as well as providing the necessary energy in rural communities. In this study, five potential seaweed species common in Irish waters, Saccorhiza polyschides, Ulva sp., Laminaria digitata, Fucus serratus and Saccharina latissima, were co-digested individually with bovine slurry. Batch reactors of 120ml and 1000ml were set up and incubated at 35 degrees C to investigate their suitability for production of biogas. Digesters fed with S. latissima produced the maximum methane yield (335 ml g volatile solids(-1) (g(VS)(-1) followed by S. polyschides with 255 ml g(VS)(-1). L. digitata produced 246ml g(VS)(-1) and the lowest yields were from the green seaweed Ulva sp. 191ml g(VS)(-1). The methane and CO2 percentages ranged between 50-72% and 10-45%, respectively. The results demonstrated that the seaweed species investigated are good feedstocks candidates for the production of biogas and methane as a source of energy. Their use on a large-scale process will require further investigation to increase yields and reduce production costs. PMID:24350482

Vanegas, C H; Bartlett, J

2013-01-01

351

Biogas scrubbing, compression and storage: perspective and prospectus in Indian context  

Microsoft Academic Search

Biogas is a clean environment friendly fuel. Raw biogas contains about 55–65% methane (CH4), 30–45% carbon dioxide (CO2), traces of hydrogen sulfide (H2S) and fractions of water vapours. Presently, it can be used only at the place where it is produced. There is a great need to make biogas transportable. This can be done by compressing the gas in cylinders

S. S. Kapdi; V. K. Vijay; S. K. Rajesh; Rajendra Prasad

2005-01-01

352

Assessment of simulated biogas as a fuel for the spark ignition engine  

Microsoft Academic Search

Results are presented of tests with a variable compression ratio Ricardo E6 single-cylinder spark-ignition engine operating on simulated biogas formed from different mixtures of domestic natural gas and carbon dioxide. The fraction of carbon dioxide in the simulated biogas was changed from 0 to about 40% by volume to cover the range typically encountered in sources of biogas in practice.

Jingdang Huang; R. J Crookes

1998-01-01

353

Initial Requirements for Gas-Cooled Fast Reactor (GFR) System Design, Performance, and Safety Analysis Models  

SciTech Connect

The gas-cooled fast reactor (GFR) was chosen as one of the Generation IV nuclear reactor systems to be developed based on its excellent potential for sustainability through reduction of the volume and radio toxicity of both its own fuel and other spent nuclear fuel, and for extending/utilizing uranium resources orders of magnitude beyond what the current open fuel cycle can realize. In addition, energy conversion at high thermal efficiency is possible with the current designs being considered, thus increasing the economic benefit of the GFR. However, research and development challenges include the ability to use passive decay heat removal systems during accident conditions, survivability of fuels and in-core materials under extreme temperatures and radiation, and economical and efficient fuel cycle processes. Nevertheless, the GFR was chosen as one of only six Generation IV systems to be pursued based on its ability to meet the Generation IV goals in sustainability, economics, safety and reliability, proliferation resistance and physical protection.

Kevan D. Weaver; Thomas Y. C. Wei

2004-08-01

354

Effect of inlet temperature on the performance of a catalytic reactor. [air pollution control  

NASA Technical Reports Server (NTRS)

A 12 cm diameter by 15 cm long catalytic reactor was tested with No. 2 diesel fuel in a combustion test rig at inlet temperatures of 700, 800, 900, and 1000 K. Other test conditions included pressures of 3 and 6 x 10 to the 5th power Pa, reference velocities of 10, 15, and 20 m/s, and adiabatic combustion temperatures in the range 1100 to 1400 K. The combustion efficiency was calculated from measurements of carbon monoxide and unburned hydrocarbon emissions. Nitrogen oxide emissions and reactor pressure drop were also measured. At a reference velocity of 10 m/s, the CO and unburned hydrocarbons emissions, and, therefore, the combustion efficiency, were independent of inlet temperature. At an inlet temperature of 1000 K, they were independent of reference velocity. Nitrogen oxides emissions resulted from conversion of the small amount (135 ppm) of fuel-bound nitrogen in the fuel. Up to 90 percent conversion was observed with no apparent effect of any of the test variables. For typical gas turbine operating conditions, all three pollutants were below levels which would permit the most stringent proposed automotive emissions standards to be met.

Anderson, D. N.

1978-01-01

355

Codigestion of manure and organic waste at centralized biogas plants  

Microsoft Academic Search

Abstract The present study focuses on process inhibitions in Danish centralized biogas plants. Collection of data from the plants and a number,of interviews sho wed that inhibitions occur frequently. High concentrations of ammonia, long chain fatty acids o r other inhibitory compounds, and foaming in prestorage tanks are well known,causes of inhibitio n. These problems,mainly occurs due to: 1) inadequate

H. b. Nielsen; I. Angelidaki

356

Production of Methane Biogas as Fuel Through Anaerobic Digestion  

Microsoft Academic Search

\\u000a Anaerobic digestion (AD) is a biotechnology by which biomass is converted by microbes to methane (CH4) biogas, which can then be utilized as a renewable fuel to generate heat and electricity. A genetically and metabolically\\u000a diverse community of microbes (mainly bacteria and methanogens) drives the AD process through a series of complex microbiological\\u000a processes in the absence of oxygen. During

Zhongtang Yu; Floyd L. Schanbacher

357

Process development of hydrogenous gas production for PEFC from biogas  

Microsoft Academic Search

A laboratory-scale gas processor that integrates four successive catalytic reactions: steam reforming of methane, high- and low-temperature water gas shifts and selective oxidation of carbon monoxide, was designed and tested in this study to produce hydrogen-rich gas with CO<10 ppm from a clean model biogas having a constant molar ratio of CH4\\/CO2=1.5:1.0 for a 50-W class polymer electrolyte fuel cell

Zhan-Guo Zhang; Guangwen Xu; Xin Chen; Kazunori Honda; Tadashi Yoshida

2004-01-01

358

Color removal from aqueous solution by biogas residual slurry  

Microsoft Academic Search

The adsorption of Acid Brilliant Blue on biogas residual slurry has been investigated. The parameters studied include dye concentration, agitation time, adsorbent dosage and pH. The equilibrium data fit well with both the Langmuir and Freundlich models of adsorption isotherm. Maximum removal of 99% was observed at pH 2.56. Desorption studies indicate that the dye is solubilised in 50%(v\\/v) acetic

R. T. Yamuna; C. Namasivayam

1993-01-01

359

Biogas as a fuel source for SOFC co-generators  

Microsoft Academic Search

This study reports on the combination of solid oxide fuel cell (SOFC) generators fueled with biogas as renewable energy source, recoverable from wastes but at present underexploited. From a mobilisable near-future potential in the European Union (EU-15) of 17 million tonnes oil equivalent (Mtoe), under 15% appears to be converted today into useful heat and power (2Mtoe).SOFCs could improve and

Jan Van herle; Yves Membrez; Olivier Bucheli

2004-01-01

360

Ecophysiological characteristics and biogas production of cadmium-contaminated crops.  

PubMed

The present study proposes a novel strategy to get a rational production of biogas of the biomass residues from phytoremediation. This study investigates physiological responses, cadmium (Cd) accumulation and biogas production from canola, oat and wheat in pot and batch experiments. The results indicate that (1) aerial biomasses for canola, oat and wheat were enhanced by 5 mg Cd/kg soil by 19.41%, 8.78% and 3.38%, and the upper limit of Cd concentration that canola, oat and wheat can tolerate for aerial biomass production were 50, 10 and 10 mg Cd/kg soil; (2) canola accumulates more Cd than oat and wheat in its aerial parts; (3) cumulative biogas yields were 159.37%, 179.23% and 111.34% of the control when Cd in the shoot were 2.00±0.44, 39.80±1.25 and 6.37±0.15 mg Cd/kg biomass for canola, oat and wheat. Phytoremediation in cooperation with bioenergy production provide new insights for both soil remediation and energy research. PMID:23978478

Zhang, Huayong; Tian, Yonglan; Wang, Lijun; Zhang, Luyi; Dai, Liming

2013-10-01

361

Performance Characterization of a Prototype Ultra-Short Channel Monolith Catalytic Reactor for Air Quality Control Applications  

NASA Technical Reports Server (NTRS)

Contaminated air and process gases, whether in a crewed spacecraft cabin atmosphere, the working volume of a microgravity science or ground-based laboratory experiment facility, or the exhaust from an automobile, are pervasive problems that ultimately effect human health, performance, and well-being. The need for highly-effective, economical decontamination processes spans a wide range of terrestrial and space flight applications. Adsorption processes are used widely for process gas decontamination. Most industrial packed bed adsorption processes use activated carbon because it is cheap and highly effective. Once saturated, however, the adsorbent is a concentrated source of contaminants. Industrial applications either dump or regenerate the activated carbon. Regeneration may be accomplished in-situ or at an off-site location. In either case, concentrated contaminated waste streams must be handled appropriately to minimize environmental impact. As economic and regulatory forces drive toward minimizing waste and environmental impact, thermal catalytic oxidation is becoming more attractive. Through novel reactor and catalyst design, more complete contaminant destruction and greater resistance to poisoning can achieved leading to less waste handling, process down-time, and maintenance. Performance of a prototype thermal catalytic reactor, based on ultra-short channel monolith (USCM) catalyst substrate design, under a variety of process flow and contaminant loading conditions is discussed. The experimental results are evaluated against present and future air quality control and process gas purification processes used on board crewed spacecraft.

Perry, J. L.; Tomes, K. M.; Roychoudhury, S.; Tatara, J. D.

2005-01-01

362

V2:Performance of the solid deuterium ultra-cold neutron source at the pulsed reactor TRIGA Mainz  

E-print Network

The performance of the solid deuterium ultra-cold neutron source at the pulsed reactor TRIGA Mainz with a maximum peak energy of 10 MJ is described. The solid deuterium converter with a volume of V=160 cm3 (8 mol), which is exposed to a thermal neutron fluence of 4.5x10^13 n/cm2, delivers up to 550 000 UCN per pulse outside of the biological shield at the experimental area. UCN densities of ~ 10/cm3 are obtained in stainless steel bottles of V ~ 10 L resulting in a storage efficiency of ~20%. The measured UCN yields compare well with the predictions from a Monte Carlo simulation developed to model the source and to optimize its performance for the upcoming upgrade of the TRIGA Mainz into a user facility for UCN physics.

J. Karch; Yu. Sobolev; M. Beck; K. Eberhardt; G. Hampel; W. Heil; R. Kieser; T. Reich; N. Trautmann; M. Ziegner

2013-08-21

363

Performance and lifetime assessment of reactor wall and nearby components during plasma instabilities.  

SciTech Connect

Surface and structural damage to plasma-facing components due to the frequent loss of plasma confinement is a serious problem for the tokamak reactor concept. The plasma energy deposited on these components during loss of confinement causes significant surface erosion, possible structural failure, and frequent plasma contamination. Surface damage consists of vaporization, spallation, and liquid splatter of metallic materials. Comprehensive multidimensional models that include thermodynamics and thermal hydraulics of plasma-facing materials, eroded-debris/vapor atomic physics and magnetohydrodynamics, resulting photon radiation and photon transport, as well as liquid splashing and brittle destruction of materials, are used self-consistently to evaluate and assess our current understanding of the lifetime of plasma-facing materials and the various forms of damage they experience. Models are developed to study the stability of the vapor shielding layer, erosion of the melt-layer, brittle destruction/explosive erosion, and the issues involved therein.

Hassanein, A.

1998-03-10

364

Containment performance analyses for the Advanced Neutron Source Reactor at the Oak Ridge National Laboratory  

SciTech Connect

This paper discusses salient aspects of methodology, assumptions, and modeling of various features related to estimation of source terms from two conservatively scoped severe accident scenarios in the Advanced Neutron Source (ANS) reactor at the Oak Ridge National Laboratory. Various containment configurations are considered for steaming-pool-type accidents and an accident involving molten core-concrete interaction. Several design features (such as rupture disks) are examined to study containment response during postulated severe accidents. Also, thermal-hydraulic response of the containment and radionuclide transport and retention in the containment are studied. The results are described as transient variations of source terms for each scenario, which are to be used for studying off-site radiological consequences and health effects for these postulated severe accidents. Also highlighted will be a comparison of source terms estimated by two different versions of the MELCOR code.

Kim, S.H.; Taleyarkhan, R.P.; Georgevich, V.

1992-10-01

365

Pyrolysis of biomass and refuse-derived fuel performance in laboratory scale batch reactor  

NASA Astrophysics Data System (ADS)

The results of pyrolysis of pine chips and refuse derived fuel fractions are presented. The experiments were carried out in a pilot pyrolysis reactor. The feedstock was analyzed by an elemental analyzer and the X-ray fluorescence spectrometer to determine the elemental composition. To find out optimum conditions for pyrolysis and mass loss as a function of temperature the thermogravimetric analysis was applied. Gases from the thermogravimetric analysis were directed to the infrared spectrometer using gas-flow cuvette to online analysis of gas composition. Chemical composition of the produced gas was measured using gas chromatography with a thermal conductivity detector and a flame ionization detector. The product analysis also took into account the mass balance of individual products.

Kluska, Jacek; Klein, Marek; Kazimierski, Pawe?; Karda?, Dariusz

2014-03-01

366

Relative neutronic performance of proposed high-density dispersion fuels in water-moderated and D{sub 2}O-reflected research reactors  

SciTech Connect

This paper provides an overview of the neutronic performance of an idealized research reactor using several high density LEU fuels that are being developed by the RERTR program. High-density LEU dispersion fuels are needed for new and existing high-performance research reactors and to extend the lifetime of fuel elements in other research reactors. This paper discusses the anticipated neutronic behavior of proposed advanced fuels containing dispersions of U{sub 3}Si{sub 2}, UN, U{sub 2}Mo and several uranium alloys with Mo, or Zr and Nb. These advanced fuels are ranked based on the results of equilibrium depletion calculations for a simplified reactor model having a small H{sub 2}O-cooled core and a D{sub 2}O reflector. Plans have been developed to fabricate and irradiate several uranium alloy dispersion fuels in order to test their stability and compatibility with the matrix material and to establish practical loading limits.

Bretscher, M.M.; Matos, J.E.; Snelgrove, J.L.

1996-12-01

367

Performance of staged and non-staged up-flow anaerobic sludge bed (USSB and UASB) reactors treating low strength complex wastewater  

Microsoft Academic Search

The use of anaerobic processes to treat low-strength wastewater has been increasing in recent years due to their favourable\\u000a performance-costs balance. For optimal results, it is necessary to identify reactor configurations that are best suited for\\u000a this kind of application. This paper reports on the comparative study carried out with two high-rate anaerobic reactor systems\\u000a with the objective of evaluating

Susana Sevilla-Espinosa; Maricela Solórzano-Campo; Ricardo Bello-Mendoza

2010-01-01

368

Titania and alumina sol-gel-derived microfluidics enzymatic-reactors for peptide mapping: design, characterization, and performance.  

PubMed

The design and characterization of titania-based and alumina-based Poly(dimethylsiloxane) (PDMS) microfluidics enzymatic-reactors along with their analytical features in coupling with MALDI-TOF and ESI-MS were reported. Microfluidics with microchannel and stainless steel tubing (SST) were fabricated using PDMS casting and O(2)-plasma techniques, and were used for the preparation of an enzymatic-reactor. Plasma oxidation for the PDMS microfluidic system enabled the channel wall of the microfluidics to present a layer of silanol (SiOH) groups. These SiOH groups act as anchors onto the microchannel wall linked covalently with the hydroxyl groups of trypsin-encapsulated sol matrix. As a result, the trypsin-encapsulated gel matrix was anchored onto the wall of the microchannel, and the leakage of gel matrix from the microchannel was effectively prevented. A feature of the microfluidic enzymatic-reactors is the feasibility of performing on-line protein analysis by attached SST electrode and replaceable tip. The success of trypsin encapsulation was investigated by AFM imaging, assay of enzymatic activity, CE detection, and MALDI-TOF and ESI-MS analysis. The lab-made devices provide an excellent extent of digestion even at a fast flow rate of 7.0 microL/min, which affords the very short residence time of ca. 2 s. With the present device, the digestion time was significantly shortened compared to conventional tryptic reaction schemes. In addition, the encapsulated trypsin exhibits increased stability even after continuous use. These features are required for high-throughput protein identification. PMID:15595729

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

2004-01-01

369

Biogas and Fuel Cells Workshop Summary Report: Proceedings from the Biogas and Fuel Cells Workshop, Golden, Colorado, June 11-13, 2012  

SciTech Connect

The U.S. Department of Energy (DOE) National Renewable Energy Laboratory (NREL) held a Biogas and Fuel Cells Workshop June 11-13, 2012, in Golden, Colorado, to discuss biogas and waste-to-energy technologies for fuel cell applications. The overall objective was to identify opportunities for coupling renewable biomethane with highly efficient fuel cells to produce electricity; heat; combined heat and power (CHP); or combined heat, hydrogen and power (CHHP) for stationary or motive applications. The workshop focused on biogas sourced from wastewater treatment plants (WWTPs), landfills, and industrial facilities that generate or process large amounts of organic waste, including large biofuel production facilities (biorefineries).

Not Available

2013-01-01

370

Treatment of agro based industrial wastewater in sequencing batch reactor: performance evaluation and growth kinetics of aerobic biomass.  

PubMed

A sequencing batch reactor (SBR) with a working volume of 8 L and an exchange ratio of 25% was used to enrich biomass for the treatment of the anaerobically treated low pH palm oil mill effluent (POME). The influent concentration was stepwise increased from 5000 ± 500 mg COD/L to 11,500 ± 500 mg COD/L. The performance of the reactor was monitored at different organic loading rates (OLRs). It was found that approximately 90% of the COD content of the POME wastewater was successfully removed regardless of the OLR applied to the SBR. Cycle studies of the SBR show that the oxygen uptake by the biomass while there is no COD reduction may be due to the oxidation of the storage product by the biomass. Further, the growth kinetic parameters of the biomass were determined in batch experiments using respirometer. The maximum specific growth rate (?max) was estimated to be 1.143 day(-1) while the half saturation constant (Ks) with respect to COD was determined to be 0.429 g COD/L. The decay coefficient (bD) and biomass yield (Y) were found to be 0.131 day(-1) and 0.272 mg biomass/mg COD consumed, respectively. PMID:25173730

Lim, J X; Vadivelu, V M

2014-12-15

371

Production of lightweight ceramisite from iron ore tailings and its performance investigation in a biological aerated filter (BAF) reactor.  

PubMed

The few reuse and large stockpile of iron ore tailings (IOT) led to a series of social and environmental problems. This study investigated the possibility of using the IOT as one of starting materials to prepare lightweight ceramisite (LWC) by a high temperature sintering process. Coal fly ash (CFA) and municipal sewage sludge (SS) were introduced as additives. The LWC was used to serve as a biomedium in a biological aerated filter (BAF) reactor for municipal wastewater treatment, and its purification performance was examined. The effects of sintering parameters on physical properties of the LWC, and leaching concentrations of heavy metals from the LWC were also determined. The microstructure and the phase composition of the LWC were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results revealed that: (1) IOT could be used to produce the LWC under the optimal sintering parameters; (2) the leaching concentrations of heavy metals from the LWC were well below their respective regulatory levels in the China Environmental Quality Standards for Surface Water (CEQS); and (3) the BAF reactor with the LWC serving as the biomedium achieved high removal efficiencies for COD(Cr) (>92%), NH(4)(+)-N (>62%) and total phosphate (T-P) (>63%). Therefore, the LWC produced from the IOT was suitable to serve as the biomedium in the municipal wastewater treatment. PMID:20227178

Liu, Yangsheng; Du, Fang; Yuan, Li; Zeng, Hui; Kong, Sifang

2010-06-15

372

Steam generator materials performance in high temperature gas-cooled reactors  

SciTech Connect

This paper reviews the materials technology aspects of steam generators for HTGRs which feature a graphite-moderated, uranium-thorium, all-ceramic core and utilizes high-pressure helium as the primary coolant. The steam generators are exposed to gas-side temperatures approaching 760/sup 0/C and produce superheated steam at 538/sup 0/C and 16.5 MPa (2400 psi). The prototype Peach Bottom I 40-MW(e) HTGR was operated for 1349 EFPD over 7 years. Examination after decommissioning of the U-tube steam generators and other components showed the steam generators to be in very satisfactory condition. The 330-MW(e) Fort St. Vrain HTGR, now in the final stages of startup, has achieved 70% power and generated more than 1.5 x 10/sup 6/ MWh of electricity. The steam generators in this reactor are once-through units of helical configuration, requiring a number of new materials factors including creep-fatigue and water chemistry control. Current designs of larger HTGRs also feature steam generators of helical once-through design. Materials issues that are important in these designs include detailed consideration of time-dependent behavior of both base metals and welds, as required by current American Society of Mechanical Engineers (ASME) Code rules, evaluation of bimetallic weld behavior, evaluation of the properties of large forgings, etc.

Chafey, J.E.; Roberts, D.I.

1980-11-01

373

Anaerobic co-digestion of food waste and landfill leachate in single-phase batch reactors.  

PubMed

In order to investigate the effect of raw leachate on anaerobic digestion of food waste, co-digestions of food waste with raw leachate were carried out. A series of single-phase batch mesophilic (35±1°C) anaerobic digestions were performed at a food waste concentration of 41.8gVS/L. The results showed that inhibition of biogas production by volatile fatty acids (VFA) occurred without raw leachate addition. A certain amount of raw leachate in the reactors effectively relieved acidic inhibition caused by VFA accumulation, and the system maintained stable with methane yield of 369-466mL/gVS. Total ammonia nitrogen introduced into the digestion systems with initial 2000-3000 mgNH4-N/L not only replenished nitrogen for bacterial growth, but also formed a buffer system with VFA to maintain a delicate biochemical balance between the acidogenic and methanogenic microorganisms. UV spectroscopy and fluorescence excitation-emission matrix spectroscopy data showed that food waste was completely degraded. We concluded that using raw leachate for supplement water addition and pH modifier on anaerobic digestion of food waste was effective. An appropriate fraction of leachate could stimulate methanogenic activity and enhance biogas production. PMID:25062938

Liao, Xiaofeng; Zhu, Shuangyan; Zhong, Delai; Zhu, Jingping; Liao, Li

2014-11-01

374

Continuously-stirred anaerobic digester to convert organic wastes into biogas: system setup and basic operation.  

PubMed

Anaerobic digestion (AD) is a bioprocess that is commonly used to convert complex organic wastes into a useful biogas with methane as the energy carrier. Increasingly, AD is being used in industrial, agricultural, and municipal waste(water) treatment applications. The use of AD technology allows plant operators to reduce waste disposal costs and offset energy utility expenses. In addition to treating organic wastes, energy crops are being converted into the energy carrier methane. As the application of AD technology broadens for the treatment of new substrates and co-substrate mixtures, so does the demand for a reliable testing methodology at the pilot- and laboratory-scale. Anaerobic digestion systems have a variety of configurations, including the continuously stirred tank reactor (CSTR), plug flow (PF), and anaerobic sequencing batch reactor (ASBR) configurations. The CSTR is frequently used in research due to its simplicity in design and operation, but also for its advantages in experimentation. Compared to other configurations, the CSTR provides greater uniformity of system parameters, such as temperature, mixing, chemical concentration, and substrate concentration. Ultimately, when designing a full-scale reactor, the optimum reactor configuration will depend on the character of a given substrate among many other nontechnical considerations. However, all configurations share fundamental design features and operating parameters that render the CSTR appropriate for most preliminary assessments. If researchers and engineers use an influent stream with relatively high concentrations of solids, then lab-scale bioreactor configurations cannot be fed continuously due to plugging problems of lab-scale pumps with solids or settling of solids in tubing. For that scenario with continuous mixing requirements, lab-scale bioreactors are fed periodically and we refer to such configurations as continuously stirred anaerobic digesters (CSADs). This article presents a general methodology for constructing, inoculating, operating, and monitoring a CSAD system for the purpose of testing the suitability of a given organic substrate for long-term anaerobic digestion. The construction section of this article will cover building the lab-scale reactor system. The inoculation section will explain how to create an anaerobic environment suitable for seeding with an active methanogenic inoculum. The operating section will cover operation, maintenance, and troubleshooting. The monitoring section will introduce testing protocols using standard analyses. The use of these measures is necessary for reliable experimental assessments of substrate suitability for AD. This protocol should provide greater protection against a common mistake made in AD studies, which is to conclude that reactor failure was caused by the substrate in use, when really it was improper user operation. PMID:22824993

Usack, Joseph G; Spirito, Catherine M; Angenent, Largus T

2012-01-01

375

Continuously-stirred Anaerobic Digester to Convert Organic Wastes into Biogas: System Setup and Basic Operation  

PubMed Central

Anaerobic digestion (AD) is a bioprocess that is commonly used to convert complex organic wastes into a useful biogas with methane as the energy carrier 1-3. Increasingly, AD is being used in industrial, agricultural, and municipal waste(water) treatment applications 4,5. The use of AD technology allows plant operators to reduce waste disposal costs and offset energy utility expenses. In addition to treating organic wastes, energy crops are being converted into the energy carrier methane 6,7. As the application of AD technology broadens for the treatment of new substrates and co-substrate mixtures 8, so does the demand for a reliable testing methodology at the pilot- and laboratory-scale. Anaerobic digestion systems have a variety of configurations, including the continuously stirred tank reactor (CSTR), plug flow (PF), and anaerobic sequencing batch reactor (ASBR) configurations 9. The CSTR is frequently used in research due to its simplicity in design and operation, but also for its advantages in experimentation. Compared to other configurations, the CSTR provides greater uniformity of system parameters, such as temperature, mixing, chemical concentration, and substrate concentration. Ultimately, when designing a full-scale reactor, the optimum reactor configuration will depend on the character of a given substrate among many other nontechnical considerations. However, all configurations share fundamental design features and operating parameters that render the CSTR appropriate for most preliminary assessments. If researchers and engineers use an influent stream with relatively high concentrations of solids, then lab-scale bioreactor configurations cannot be fed continuously due to plugging problems of lab-scale pumps with solids or settling of solids in tubing. For that scenario with continuous mixing requirements, lab-scale bioreactors are fed periodically and we refer to such configurations as continuously stirred anaerobic digesters (CSADs). This article presents a general methodology for constructing, inoculating, operating, and monitoring a CSAD system for the purpose of testing the suitability of a given organic substrate for long-term anaerobic digestion. The construction section of this article will cover building the lab-scale reactor system. The inoculation section will explain how to create an anaerobic environment suitable for seeding with an active methanogenic inoculum. The operating section will cover operation, maintenance, and troubleshooting. The monitoring section will introduce testing protocols using standard analyses. The use of these measures is necessary for reliable experimental assessments of substrate suitability for AD. This protocol should provide greater protection against a common mistake made in AD studies, which is to conclude that reactor failure was caused by the substrate in use, when really it was improper user operation 10. PMID:22824993

Usack, Joseph G.; Spirito, Catherine M.; Angenent, Largus T.

2012-01-01

376

Resolving operational and performance problems encountered in the use of a pilot/full-scale biotrickling filter reactor  

SciTech Connect

A pilot/full-scale biotrickling filter reactor experiment was performed at an industrial site to treat styrene laden waste gas. The engineered system consisted of two stainless steel tanks in series, each with filter bed volumes of 4.0 m{sup 3}, filled with 3.5-inch plastic spheres. The system treated 340 m{sup 3} h{sup {minus}1} of air laden with styrene concentrations ranging up to 0.8 g m{sup {minus}3}. Over the five-month study, styrene elimination was demonstrated up to 24 g m{sup {minus}3} H{sup {minus}1} with 70 to 85% removal. Operational and performance problems were identified that differ from those developed under controlled, laboratory set-ups. Operational problems typically involved equipment malfunctions, with the most prone to failure pieces of equipment being the air sampling system and water level sensors. Performance problems were identified that possibly limited the styrene removal. The transient operation of the plant, producing discontinuous, unsteady-state concentrations, made it difficult to establish a stable biofilm on the packing material. Experiments were performed indicating both biological and mass transfer limitations may have occurred.

Webster, T.S.; Cox, H.H.J.; Deshusses, M.A.

1999-09-30

377

Nonlinear Autoregressive Exogenous modeling of a large anaerobic digester producing biogas from cattle waste.  

PubMed

In waste-to-energy plants, there is every likelihood of variations in the quantity and characteristics of the feed. Although intermediate storage tanks are used, but many times these are of inadequate capacity to dampen the variations. In such situations an anaerobic digester treating waste slurry operates under dynamic conditions. In this work a special type of dynamic Artificial Neural Network model, called Nonlinear Autoregressive Exogenous model, is used to model the dynamics of anaerobic digesters by using about one year data collected on the operating digesters. The developed model consists of two hidden layers each having 10 neurons, and uses 18days delay. There are five neurons in input layer and one neuron in output layer for a day. Model predictions of biogas production rate are close to plant performance within ±8% deviation. PMID:25151079

Dhussa, Anil K; Sambi, Surinder S; Kumar, Shashi; Kumar, Sandeep; Kumar, Surendra

2014-10-01

378

Monitoring feedwater flow rate and component thermal performance of pressurized water reactors by means of artificial neural networks  

SciTech Connect

The fouling of venturi meters, used for steam generator feedwater flow rate measurement in pressurized water reactors (PWRs), may result in unnecessary plant power derating. On-line monitoring of these important instrument channels and the thermal efficiencies of the balance-of-plant components are addressed. The steam generator feedwater flow rate and thermal efficiencies of critical components in a PWR are estimated by means of artificial neural networks. The physics of these systems and appropriate plant measurements are combined to establish robust neural network models for on-line prediction of feedwater flow rate and thermal efficiency of feedwater heaters in PWRs. A statistical sensitivity analysis technique was developed to establish the performance of this methodology.

Kavaklioglu, K.; Upadhyaya, B.R. (Univ. of Tennessee, Knoxville, TN (United States). Dept. of Nuclear Engineering)

1994-07-01

379

Influence of carrier filling ratio on the performance of moving bed biofilm reactor in treating coking wastewater.  

PubMed

This study aims to evaluate the effect of carrier filling ratio on the performance of a moving bed biofilm reactor in degrading chemical oxygen demand, phenol, thiocyanate, and ammonia from coking wastewater at 20h of hydraulic retention time. The operational experiments under different carrier filling ratios ranging from 20% to 60% were investigated. The maximum removal efficiency of 89%, 99% and 99% for COD, phenol and thiocyanate, and minimum sensitivity to the increasing contaminants concentration in the influent were achieved at 50% carrier filling ratio. The Haldane competitive substrate inhibition kinetics model was used to describe the relationship between the oxygen uptake rate of ammonium oxidizers and the concentration of free ammonium. The highest biofilm microbial community functional diversity (Shannon's diversity index, H') and evenness (Shannon's evenness index, E') were obtained at 50% carrier filling ratio in all runs using a Biolog ECO microplate. PMID:24907566

Gu, Qiyuan; Sun, Tichang; Wu, Gen; Li, Mingyue; Qiu, Wei

2014-08-01

380

Identification of the microbiological community in biogas systems and evaluation of microbial risks from gas usage  

Microsoft Academic Search

The plans for introducing biogas produced from organic waste to the pipe system for natural gas has raised concerns about the risk of transmitting disease via the gas. To assess this risk, condensate water from gas pipes and gas from different parts of a biogas upgrading system were sampled and cultured for microbial content. On average, 105 cfu ml?1 were found in

Björn Vinnerås; Caroline Schönning; Annika Nordin

2006-01-01

381

Comparative study of mechanical, hydrothermal, chemical and enzymatic treatments of digested biofibers to improve biogas production  

Microsoft Academic Search

Organic waste such as manure is an important resource for biogas production. The biodegradability of manures is however limited because of the recalcitrant nature of the biofibers it contains. To increase the biogas potential of the biofibers in digested manure, we investigated physical treatment (milling), chemical treatment (CaO), biological treatment (enzymatic and partial aerobic microbial conversion), steam treatment with catalyst

Emiliano Bruni; Anders Peter Jensen; Irini Angelidaki

2010-01-01

382

Enhancement of biogas production from solid substrates using different techniques––a review  

Microsoft Academic Search

Biogas, a clean and renewable form of energy could very well substitute (especially in the rural sector) for conventional sources of energy (fossil fuels, oil, etc.) which are causing ecological–environmental problems and at the same time depleting at a faster rate. Despite its numerous advantages, the potential of biogas technology could not be fully harnessed or tapped as certain constraints

Yadvika; Santosh; T. R. Sreekrishnan; Sangeeta Kohli; Vineet Rana

2004-01-01

383

Technical and economic analysis of biogas production in Ireland utilising three different crop rotations  

Microsoft Academic Search

The Biofuels Directive sets reference values for the quantity of biofuels and other renewable fuels to be placed on the transport market. Biogas from agricultural crops can be used to meet this directive. This paper investigates biogas production for three crop rotations: wheat, barley and sugar beet; wheat, wheat and sugar beet; wheat only. A technical and economic analysis for

J. D. Murphy; N. Power

2009-01-01

384

Comparative study of economics of different models of family size biogas plants for state of Punjab, India  

Microsoft Academic Search

Biogas, the end product of anaerobic digestion of cattle dung, can successfully supplement the cooking fuels in the countryside areas of India, where the raw material needed for its production is plentifully available. Because of the lack of awareness regarding selection of a suitable model and size of biogas plant, the full potential of the biogas producing material is not

K. Jatinder Singh; Sarbjit Singh Sooch

2004-01-01

385

5th International Landfills Conference -Sardinia'95, Cagliari, 1995 DEVELOPMENT AND VALIDATION OF A METHOD FOR MEASURING BIOGAS  

E-print Network

OF A METHOD FOR MEASURING BIOGAS EMISSIONS USING A DYNAMIC CHAMBER Zbigniew POKRYSZKA, Christian TAUZIEDE biogas flow, designing a dynamic flux chamber. Preliminary bench tests revealed the necessity of defining gas releases. A mixture of gases (known as biogas) is produced from organic waste, and consists mainly

Paris-Sud XI, Université de

386

Environmental systems analysis of biogas systems—Part II: The environmental impact of replacing various reference systems  

Microsoft Academic Search

This paper analyses the overall environmental impact when biogas systems are introduced and replace various reference systems for energy generation, waste management and agricultural production. The analyses are based on Swedish conditions using a life-cycle perspective. The biogas systems included are based on different combinations of raw materials and final use of the biogas produced (heat, power and transportation fuel).

Pål Börjesson; Maria Berglund

2007-01-01

387

Nonrenewable Energy Cost and Greenhouse Gas Emissions of a "Pig-Biogas-Fish" System in China  

PubMed Central

The purpose of this study is to assess the energy savings and emission reductions of the present rural biogas system in China. The life cycle assessment (LCA) method is used to analyze a “pig-biogas-fish” system in Jingzhou, Hubei Province, China. The nonrenewable energy cost and the greenhouse gas (GHG) emissions of the system, including the pigsty, the biogas digester, and the fishpond, are taken into account. The border definition is standardized because of the utilization of the database in this paper. The results indicate that the nonrenewable energy consumption intensity of the “pig-biogas-fish” system is 0.60?MJ/MJ and the equivalent CO2 emission intensity is 0.05?kg CO2-eq/MJ. Compared with the conventional animal husbandry system, the “pig-biogas-fish” system shows high renewability and GHG reduction benefit, which indicates that the system is a scientific and environmentally friendly chain combining energy and ecology. PMID:23213302

Yang, Qing; Wu, Xiaofang; Yang, Haiping; Zhang, Shihong; Chen, Hanping

2012-01-01

388

pH regulation of alkaline wastewater with carbon dioxide: A case study of treatment of brewery wastewater in UASB reactor coupled with absorber  

Microsoft Academic Search

Studies were carried out with carbon dioxide absorber (CA) to evaluate the usage of carbon dioxide (CO2) in the biogas as an acidifying agent by Up-flow Anaerobic Sludge Blanket (UASB) reactor. Investigation on the 5l absorber revealed that ratio of brewery wastewater (BW) flow rate to biogas flow rate of 4.6–5.2 was optimum for minimum consumption of CO2 for acidification.

A. Gangagni Rao; T. Sasi Kanth Reddy; S. Surya Prakash; J. Vanajakshi; Johny Joseph; P. N. Sarma

2007-01-01

389

Siloxanes removal from biogas by high surface area adsorbents.  

PubMed

Biogas utilized for energy production needs to be free from organic silicon compounds, as their burning has damaging effects on turbines and engines; organic silicon compounds in the form of siloxanes can be found in biogas produced from urban wastes, due to their massive industrial use in synthetic product, such as cosmetics, detergents and paints. Siloxanes removal from biogas can be carried out by various methods (Mona, 2009; Ajhar et al., 2010 May; Schweigkofler and Niessner, 2001); aim of the present work is to find a single practical and economic way to drastically and simultaneously reduce both the hydrogen sulphide and the siloxanes concentration to less than 1 ppm. Some commercial activated carbons previously selected (Monteleone et al., 2011) as being effective in hydrogen sulfide up taking have been tested in an adsorption measurement apparatus, by flowing the most volatile siloxane (hexamethyldisiloxane or L2) in a nitrogen stream, typically 100-200 ppm L2 over N2, through an activated carbon powder bed; the adsorption process was analyzed by varying some experimental parameters (concentration, grain size, bed height). The best activated carbon shows an adsorption capacity of 0.1g L2 per gram of carbon. The next thermogravimetric analysis (TGA) confirms the capacity data obtained experimentally by the breakthrough curve tests. The capacity results depend on L2 concentration. A regenerative carbon process is then carried out by heating the carbon bed up to 200 °C and flushing out the adsorbed L2 samples in a nitrogen stream in a three step heating procedure up to 200 °C. The adsorption capacity is observed to degrade after cycling the samples through several adsorption-desorption cycles. PMID:24075968

Gislon, P; Galli, S; Monteleone, G

2013-12-01

390

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

Microsoft Academic Search

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

E. Kujawski; C. R. Weisbin

1982-01-01

391

Performance of cable-in-conduit conductors in ITER (International Thermonuclear Experimental Reactor) toroidal field coils with varying heat loads  

SciTech Connect

The toroidal field (TF) coils in the International Thermonuclear Experimental Reactor (ITER) will operate with varying heat loads generated by ac losses and nuclear heating. The total heat load is estimated to be 2 kW per TF coil under normal operation and can be higher for different operating scenarios. Ac losses are caused by ramping the poloidal field (PF) for plasma initiation, burn, and shutdown; nuclear heating results from neutrons that penetrate into the coil past the shield. Present methods to reduce or eliminate these losses lead to larger and more expensive machines, which are unacceptable with today's budget constraints. A suitable solution is to design superconductors that operate with high heat loads. The cable-in-conduit conductor (CICC) can operate with high heat loads. One CICC design is analyzed for its thermal performance using two computer codes developed at LLNL. One code calculates the steady state flow conditions along the flow path, while the other calculates the transient conditions in the flow. We have used these codes to analyze the superconductor performance during the burn phase of the ITER plasma. The results of these analyses give insight to the choice of flow rate on superconductor performance. 4 refs., 5 figs.

Kerns, J.A.; Wong, R.L.

1989-09-20

392

On-farm biogas systems information dissemination project. Final report  

SciTech Connect

The purpose of this project was to study how farmers manage anaerobic digesters on three New York State dairy farms. Two years of data collected were from both plug-flow and tower-type mixed-flow digesters at regular intervals over a three-year period revealed that the financial return from the energy produced by a biogass system in the late 1980`s is marginal. Little difficulty was experienced in operation of the anaerobic digester; however, several farms utilizing congeneration to convert biogas into electricity and heat suffered from not applying maintenance to the congenerator in a timely fashion.

Campbell, J.K.; Koelsch, R.K.; Guest, R.W.; Fabian, E.

1997-03-01

393

Biogas production from anaerobic digestion of Spirulina maxima algal biomass  

SciTech Connect

Spirulina maxima algal biomass could be used as the sole nutrient for the production of biogas by anaerobic digestion process. It is relatively simple to adapt the municipal sewage sludge to this new substrate. The adapted sludge is very stable. Under nonoptimal conditions, the methane yield and productivity obtained were 0.26 m/sup 3//(kg VS added day) and 0.26 m/sup 3//(kg VS added day), respectively, with the semicontinuous, daily fed, anaerobic digestion having loading rate of 0.97 kg VS/(m/sup 3/ day), retention time of 33 days and temperature of 30/sup 0/C.

Rejean Samson; Anh LeDuy

1982-08-01

394

International Thermonuclear Experimental Reactor (ITER) divertor plate performance and lifetime considerations  

SciTech Connect

The ITER divertor plate performance during the technology phase of operation has been analyzed. High-Z materials, such as tungsten and tantalum, have been considered as plasma side materials, and refractory metal alloys, Ta-10W, TZM, Nb-1Zr, and V-15Cr-5Ti, plus copper alloys have been considered as the structural materials. The fatigue lifetime have been predicted for structural plates and for duplex plates with the plasma side material bonded to the structure. The results indicate that refractory alloys have a comparable or improved performance to copper alloys. Peak allowable heat fluxes for these analyses are in the range of 15--20 MW/m{sup 2} for 2 mm thick structural plates and 7--11 MW/m{sup 2} for 4 mm thick duplex plates. 4 refs., 55 figs., 6 tabs.

Mattas, R.F.

1990-03-01

395

FSV experience in support of the GT-MHR reactor physics, fuel performance, and graphite  

SciTech Connect

The Fort St. Vrain (FSV) power plant was the most recent operating graphite-moderated, helium-cooled nuclear power plant in the United States. Many similarities exist between the FSV design and the current design of the GT-MHR. Both designs use graphite as the basic building blocks of the core, as structural material, in the reflectors, and as a neutron moderator. Both designs use hexagonal fuel elements containing cylindrical fuel rods with coated fuel particles. Helium is the coolant and the power densities vary by less than 5%. Since material and geometric properties of the GT-MHR core am very similar to the FSV core, it is logical to draw upon the FSV experience in support of the GT-MHR design. In the Physics area, testing at FSV during the first three cycles of operation has confirmed that the calculational models used for the core design were very successful in predicting the core nuclear performance from initial cold criticality through power operation and refueling. There was excellent agreement between predicted and measured initial core criticality and control rod positions during startup. Measured axial flux distributions were within 5% of the predicted value at the peak. The isothermal temperature coefficient at zero power was in agreement within 3%, and even the calculated temperature defect over the whole operating range for cycle 3 was within 8% of the measured defect. In the Fuel Performance area, fuel particle coating performance, and fission gas release predictions and an overall plateout analysis were performed for decommissioning purposes. A comparison between predicted and measured fission gas release histories of Kr-85m and Xe-138 and a similar comparison with specific circulator plateout data indicated good agreement between prediction and measured data. Only I-131 plateout data was overpredicted, while Cs-137 data was underpredicted.

Baxter, A.M.; McEachern, D.; Hanson, D.L.; Vollman, R.E.

1994-11-01

396

Root-cause analysis of the better performance of the coarse-mesh finite-difference method for CANDU-type reactors  

SciTech Connect

Recent assessment results indicate that the coarse-mesh finite-difference method (FDM) gives consistently smaller percent differences in channel powers than the fine-mesh FDM when compared to the reference MCNP solution for CANDU-type reactors. However, there is an impression that the fine-mesh FDM should always give more accurate results than the coarse-mesh FDM in theory. To answer the question if the better performance of the coarse-mesh FDM for CANDU-type reactors was just a coincidence (cancellation of errors) or caused by the use of heavy water or the use of lattice-homogenized cross sections for the cluster fuel geometry in the diffusion calculation, three benchmark problems were set up with three different fuel lattices: CANDU, HWR and PWR. These benchmark problems were then used to analyze the root cause of the better performance of the coarse-mesh FDM for CANDU-type reactors. The analyses confirm that the better performance of the coarse-mesh FDM for CANDU-type reactors is mainly caused by the use of lattice-homogenized cross sections for the sub-meshes of the cluster fuel geometry in the diffusion calculation. Based on the analyses, it is recommended to use 2 x 2 coarse-mesh FDM to analyze CANDU-type reactors when lattice-homogenized cross sections are used in the core analysis. (authors)

Shen, W. [Candu Energy Inc., 2285 Speakman Dr., Mississauga, ON L5B 1K (Canada)

2012-07-01

397

Searching for links in the biotic characteristics and abiotic parameters of nine different biogas plants  

PubMed Central

Summary To find links between the biotic characteristics and abiotic process parameters in anaerobic digestion systems, the microbial communities of nine full?scale biogas plants in South Tyrol (Italy) and Vorarlberg (Austria) were investigated using molecular techniques and the physical and chemical properties were monitored. DNA from sludge samples was subjected to microarray hybridization with the ANAEROCHIP microarray and results indicated that sludge samples grouped into two main clusters, dominated either by Methanosarcina or by Methanosaeta, both aceticlastic methanogens. Hydrogenotrophic methanogens were hardly detected or if detected, gave low hybridization signals. Results obtained using denaturing gradient gel electrophoresis (DGGE) supported the findings of microarray hybridization. Real?time PCR targeting Methanosarcina and Methanosaeta was conducted to provide quantitative data on the dominating methanogens. Correlation analysis to determine any links between the microbial communities found by microarray analysis, and the physicochemical parameters investigated was conducted. It was shown that the sludge samples dominated by the genus Methanosarcina were positively correlated with higher concentrations of acetate, whereas sludge samples dominated by representatives of the genus Methanosaeta had lower acetate concentrations. No other correlations between biotic characteristics and abiotic parameters were found. Methanogenic communities in each reactor were highly stable and resilient over the whole year. PMID:22950603

Walter, Andreas; Knapp, Brigitte A.; Farbmacher, Theresa; Ebner, Christian; Insam, Heribert; Franke-Whittle, Ingrid H.

2012-01-01

398

Comparison of UASB and EGSB reactors performance, for treatment of raw and deoiled palm oil mill effluent (POME).  

PubMed

Anaerobic digestion of palm oil mill effluent (POME) and deoiled POME was investigated both in batch assays and continuous reactor experiments using up-flow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors. The methane potential determined from batch assays of POME and deoiled POME was 503 and 610 mL-CH(4)/gVS-added, respectively. For the treatment of POME in continuously fed reactors, both in UASB and EGSB reactors more than 90% COD removal could be obtained, at HRT of 5 days, corresponding to OLR of 5.8 gVS/(L-reactor.d). Similar methane yields of 436-438 mL-CH(4)/gVS-added were obtained for UASB and EGSB respectively. However, for treatment of deoiled POME, both UASB and EGSB reactors could operate at lower OLR of 2.6 gVS/(L-reactor.d), with the methane yield of 600 and 555 mL-CH(4)/gVS-added for UASB and EGSB, respectively. The higher methane yield achieved from the deoiled POME was attributed to lower portion of biofibers which are more recalcitrant compared the rest of organic matter in POME. The UASB reactor was found to be more stable than EGSB reactor under the same OLR, as could be seen from lower VFA concentration, especially propionic acid, compared to the EGSB reactor. PMID:21377272

Fang, Cheng; O-Thong, Sompong; Boe, Kanokwan; Angelidaki, Irini

2011-05-15

399

Chinese Biogas Digester. A Potential Model for Small-Scale, Rural Applications. (A Manual for Construction and Operation). Reprint No. R-51.  

ERIC Educational Resources Information Center

This book provides the basic knowledge and guides for the construction and operation of a small-scale, family-size biogas unit. The first chapter discusses the benefits of biogas production and the Chinese biogas model. The second chapter shows the components, design formulas, and sizing units of the biogas model. Chapter 3 describes actual…

Nakagawa, Charles H.; Honquilada, Q. L.

400

Neutronic performance of high-density LEU fuels in water-moderated and water-reflected research reactors  

SciTech Connect

At the Reduced Enrichment for Research and Test Reactors (RERTR) meeting in September 1994, Durand reported that the maximum uranium loading attainable with U{sub 3}Si{sub 2} fuel is about 6.0 g U/cm{sup 3}. The French Commissariat a l`Energie Atomique (CEA) plan to perform irradiation tests with 5 plates at this loading. Compagnie pour L`Etude et La Realisation de Combustibles Atomiques (CERCA) has also fabricated a few uranium nitride (UN) plates with a uranium density in the fuel meat of 7.0 g/cm{sup 3} and found that UN is compatible with the aluminum matrix at temperatures below 500 C. High density dispersion fuels proposed for development include U-Zr(4 wt%)-Nb(2 wt%), U-Mo(5 wt%), and U-Mo(9 wt%). The purpose of this note is to examine the relative neutronic behavior of these high density fuels in a typical light water-reflected and water-moderated MTR-type research reactor. The results show that a dispersion of the U-Zr-Nb alloy has the most favorable neutronic properties and offers the potential for uranium densities greater than 8.0 g/cm{sup 3}. On the other hand, UN is the least reactive fuel because of the relatively large {sup 14}N(n,p) cross section. For a fixed value of k{sub eff}, the required {sup 235}U loading per fuel element is least for the U-Zr-Nb fuel and steadily increases for the U-Mo(5%), U-Mo(9%), and UN fuels. Because of volume fraction limitations, the UO{sub 2} dispersions are only useful for uranium densities below 5.0 g/cm{sup 3}. In this density range, however, UO{sub 2} is more reactive than U{sub 3}Si{sub 2}.

Bretscher, M.M.; Matos, J.E.

1996-09-01

401

Experimental Breeder Reactor II (EBR-II) Fuel-Performance Test Facility (FPTF)  

SciTech Connect

The Fuel-Performance Test Facility (FPTF) is the latest in a series of special EBR-II instrumented in-core test facilities. A flow control valve in the facility is programmed to vary the coolant flow, and thus the temperature, in an experimental-irradiation subassembly beneath it and coupled to it. In this way, thermal transients can be simulated in that subassembly without changing the temperatures in surrounding subassemblies. The FPTF also monitors sodium flow and temperature, and detects delayed neutrons in the sodium effluent from the experimental-irradiation subassembly beneath it. This facility also has an acoustical detector (high-temperature microphone) for detecting sodium boiling.

Pardini, J.A.; Brubaker, R.C.; Veith, D.J.; Giorgis, G.C.; Walker, D.E.; Seim, O.S.

1982-01-01

402

Individual plant examination program: Perspectives on reactor safety and plant performance. Part 1: Final summary report; Volume 1  

SciTech Connect

This report provides perspectives gained by reviewing 75 Individual Plant Examination (IPE) submittals pertaining to 108 nuclear power plant units. IPEs are probabilistic analyses that estimate the core damage frequency (CDF) and containment performance for accidents initiated by internal events. The US Nuclear Regulatory Commission (NRC) reviewed the IPE submittals with the objective of gaining perspectives in three major areas: (1) improvements made to individual plants as a result of their IPEs and the collective results of the IPE program, (2) plant-specific design and operational features and modeling assumptions that significantly affect the estimates of CDF and containment performance, and (3) strengths and weaknesses of the models and methods used in the IPEs. These perspectives are gained by assessing the core damage and containment performance results, including overall CDF, accident sequences, dominant contributions to component failure and human error, and containment failure modes. Methods, data, boundary conditions, and assumptions used in the IPEs are considered in understanding the differences and similarities observed among the various types of plants. This report is divided into three volumes containing six parts. Part 1 is a summary report of the key perspectives gained in each of the areas identified above, with a discussion of the NRC`s overall conclusions and observations. Part 2 discusses key perspectives regarding the impact of the IPE Program on reactor safety. Part 3 discusses perspectives gained from the IPE results regarding CDF, containment performance, and human actions. Part 4 discusses perspectives regarding the IPE models and methods. Part 5 discusses additional IPE perspectives. Part 6 contains Appendices A, B and C which provide the references of the information from the IPEs, updated PRA results, and public comments on draft NUREG-1560 respectively.

NONE

1997-12-01

403

Use of new membrane-reactor saccharification assay to evaluate the performance of cellulases under simulated SSF conditions  

SciTech Connect

A new saccharification assay has been devised, in which a continuously buffer-swept membrane reactor is used to remove the solubilized saccharification products, thus allowing high extents of substrate conversion without significant inhibitory effects from the buildup of either cellobiose or glucose. This diafiltration saccharification assay (DSA) can, therefore, be used to obtain direct measurements of the performance of combinations of cellulose and substrate under simulated SSF conditions, without the saccharification results being complicated by factors that may influence the subsequent fermentation step. This assay has been used to compare the effectiveness of commercial and special in-house-produced Trichoderma reesei cellulose preparations in the saccharification of a standardized microcrystalline (Sigmacell) substrate and a dilute-acid pretreated lignocellulosic substrate. Initial results strongly suggest that enzyme preparations produced in the presence of the targeted lignocellulosic substrate will saccharify that substrate more effectively. These results call into question the widespread use of the {open_quotes}filter paper assay{close_quotes} as a reliable predictor of enzyme performance in the extensive hydrolysis of substrates that are quite different from filter paper in both physical properties and chemical composition. 14 refs., 6 figs.

Baker, J.O.; Vinzant, T.B.; Ehrman, C.I. [National Renewable Energy Lab., Golden, CO (United States)] [and others

1997-12-31

404

Effect of particle size on the performance of autotrophic nitrogen removal in the granular sludge bed reactor and microbiological mechanisms.  

PubMed

The effect of particle size on the performance of autotrophic nitrogen removal in the granular sludge bed reactor (GSB-ANR) and microbiological mechanisms were investigated. The results indicated that performance of GSB-ANR process decreased gradually with the increase of the granular sludge size. Indeed small granules ranging between 0.5 and 0.9mm had a higher nitrogen removal capacity than large ones. The reasons of this effect were that (i) the aerobic ammonium oxidizing capacity of microorganisms was the bottle neck of nitrogen removal in GSB-ANR process, and the increase of aerobic ammonium oxidizing activity enhances nitrite production in nitrification and promotes subsequent nitrite consumption during anaerobic ammonia oxidation; (ii) the aerobic/anaerobic zone separation in granular sludge was the key factor affecting the aerobic ammonium oxidizing capacity of microorganisms. The small granules had a larger aerobic functional zone (75.1%) which was profitable for up-regulating the expression level of functional gene in aerobic ammonium oxidizing microorganisms. PMID:24561629

Wang, Lan; Zheng, Ping; Xing, Yajuan; Li, Wei; Yang, Jian; Abbas, Ghulam; Liu, Shuai; He, Zhanfei; Zhang, Jiqiang; Zhang, Hongtao; Lu, Huifeng

2014-04-01

405

Biogas production from anaerobic digestion of Spirulina maxima algal biomass  

SciTech Connect

The photosynthetic spectrum of solar energy could be exploited for the production of chemical energy of methane through the combined algal-bacterial process. In this process, the algae are mass produced from light and from carbon in the first step. The algal biomass is then used as a nutrient for feeding the anaerobic digester, in the second step, for the production of methane by anaerobic bacteria. The carbon source for the production of algal biomass could be either organic carbon from wastewaters (for eucaryotic algae), or carbon dioxide from the atmosphere or from the combustion exhaust gases (for both prokaryotic and eukaryotic algae). The technical feasibility data on the anaerobic digestion of algal biomass have been reported for many species of algae including macroscopic algae and microscopic algae. Research being conducted in the authors' laboratory consists of using the semimicroscopic blue-green alga Spirulina maxima as the sole substrate for this combined algal-bacterial process. This species of alga is very attractive for the process because of its capability of using the atmospheric carbon dioxide as carbon source and its simple harvesting methods. Furthermore, it appeared that the fermentability of S. maxima is significantly higher than other microscopic algae. This communication presents the results on the anaerobic inoculum development by the adaptation technique. This inoculum was then used for the semicontinuous anaerobic digestion of S. maxima algal biomass. The evolutions of biogas production and composition, biogas yield, total volatile fatty acids, alkalinity, ammonia nitrogen, pH, and electrode potential were followed.

Samson, R.; LeDuy, A.

1982-08-01

406

Biological treatment of chicken feather waste for improved biogas production.  

PubMed

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 after 8 days of cultivation of the recombinant strain. During the subsequent anaerobic batch digestion experiments, methane production of 0.35 Nm3/kg dry feathers (i.e., 0.4 Nm3/kg volatile solids of feathers), corresponding to 80% of the theoretical value on proteins, was achieved from the feather hydrolyzates, independently of the pre-hydrolysis time period of 1, 2 or 8 days. Cultivation with a native keratinase producing strain, Bacillus licheniformis resulted in only 0.25 mg/mL soluble proteins in the feather hydrolyzate, which then was digested achieving a maximum accumulated methane production of 0.31 Nm3/kg dry feathers. Feather hydrolyzates treated with the wild type B. megaterium produced 0.21 Nm3 CH4/kg dry feathers as maximum yield. PMID:22432272

Forgács, Gergely; Alinezhad, Saeid; Mirabdollah, Amir; Feuk-Lagerstedt, Elisabeth; Horváth, Ilona Sárvári

2011-01-01

407

Biogas upgrading: optimal activated carbon properties for siloxane removal.  

PubMed

A total of 12 commercial activated carbons (ACs) have been tested for the removal of octamethylcyclotetrasiloxane (D4) in dynamic adsorption experiments using different carrier gases and D4 concentrations. Characterization of the ACs included several physical and chemical techniques. The D4 adsorption capacities were strongly related with the textural development of the ACs. Results showed that the optimum adsorbent for D4 is a wood-based chemically activated carbon, which rendered an adsorption capacity of 1732 ± 93 mg g(-1) using 1000 ppm (v/v) of D4 with dry N2 as the carrier gas. When the concentration of D4 was lowered to typical values found in biogas, the adsorption capacity was halved. The presence of major biogas compounds (i.e., CH4 and CO2) and humidity further reduced the D4 adsorption capacity. The polymerization of D4 over the surface of all ACs was found to be relevant after prolonged contact times. The extent of this phenomenon, which may negatively affect the thermal regeneration of the AC, correlated reasonably well with the presence of phenolic and carboxylic groups on the carbon surfaces. PMID:24837651

Cabrera-Codony, Alba; Montes-Morán, Miguel A; Sánchez-Polo, Manuel; Martín, Maria J; Gonzalez-Olmos, Rafael

2014-06-17

408

TIBER II/ETR: Nuclear Performance Analysis Group Report. [TIBER II Engineering Test Reactor  

SciTech Connect

A Nuclear Performance Analysis Group was formed to develop the nuclear technology mission of TIBER-II under the leadership of Argonne National Laboratory reporting to LLNL with major participation by the University of California - Los Angeles (test requirements, R and D needs, water-cooled test modules, neutronic tests). Additional key support was provided by GA Technologies (helium-cooled test modules), Hanford Engineering Development Laboratory (material-irradiation tests), Sandia National Laboratory - Albuquerque (high-heat-flux component tests), and the Idaho National Engineering Laboratory (safety tests). Support also was provided by Rennselaer Polytechnic Institute, Grumman Aerospace Corporation, and the Canadian Fusion Fuels Technology Program. This report discusses these areas and provides a schedule for their completion.

Not Available

1987-09-01

409

Controlled continuous bio-hydrogen production using different biogas release strategies.  

PubMed

Dark fermentation for bio-hydrogen (bio-H2) production is an easily operated and environmentally friendly technology. However, low bio-H2 production yield has been reported as its main drawback. Two strategies have been followed in the past to improve this fact: genetic modifications and adjusting the reaction conditions. In this paper, the second one is followed to regulate the bio-H2 release from the reactor. This operating condition alters the metabolic pathways and increased the bio-H2 production twice. Gas release was forced in the continuous culture to study the equilibrium in the mass transfer between the gaseous and liquid phases. This equilibrium depends on the H2, CO2, and volatile fatty acids production. The effect of reducing the bio-H2 partial pressure (bio-H2?pp) to enhance bio-H2 production was evaluated in a 30 L continuous stirred tank reactor. Three bio-H2 release strategies were followed: uncontrolled, intermittent, and constant. In the so called uncontrolled fermentation, without bio-H2?pp control, a bio-H2 molar yield of 1.2 mol/mol glucose was obtained. A sustained low bio-H2?pp of 0.06 atm increased the bio-H2 production rate from 16.1 to 108 mL/L/h with a stable bio-H2 percentage of 55% (v/v) and a molar yield of 1.9 mol/mol glucose. Biogas release enhanced bio-H2 production because lower bio-H2 pp, CO2 concentration, and reduced volatile fatty acids accumulation prevented the associated inhibitions and bio-H2 consumption. PMID:24879593

Esquivel-Elizondo, S; Chairez, I; Salgado, E; Aranda, J S; Baquerizo, G; Garcia-Peña, E I

2014-08-01

410

Cassava Stillage Treatment by Thermophilic Anaerobic Continuously Stirred Tank Reactor (CSTR)  

NASA Astrophysics Data System (ADS)

This paper assesses the performance of a thermophilic anaerobic Continuously Stirred Tank Reactor (CSTR) in the treatment of cassava stillage under various organic loading rates (OLRs) without suspended solids (SS) separation. The reactor was seeded with mesophilic anaerobic granular sludge, and the OLR increased by increments to 13.80 kg COD/m3/d (HRT 5d) over 80 days. Total COD removal efficiency remained stable at 90%, with biogas production at 18 L/d (60% methane). Increase in the OLR to 19.30 kg COD/m3/d (HRT 3d), however, led to a decrease in TCOD removal efficiency to 79% due to accumulation of suspended solids and incomplete degradation after shortened retention time. Reactor performance subsequently increased after OLR reduction. Alkalinity, VFA and pH levels were not significantly affected by OLR variation, indicating that no additional alkaline or pH adjustment is required. More than half of the SS in the cassava stillage could be digested in the process when HRT was 5 days, which demonstrated the suitability of anaerobic treatment of cassava stillage without SS separation.

Luo, Gang; Xie, Li; Zou, Zhonghai; Zhou, Qi

2010-11-01

411

Influence of anaerobic co-digestion of sewage and brewery sludges on biogas production and sludge quality.  

PubMed

This research investigated operating parameters and treatment efficiency for the digestion of sewage and brewery sludge. The prime objective of this study was to enhance the quality of treated sludge for use as agriculture fertilizer and to enhance biogas production, a by-product that can be used as an energy source. Three bench-scale completely stirred tank reactor (CSTR) anaerobic digesters were operated at mesophilic condition (36+/-0.2 degrees C). A mixture of sewage and brewery sludge were used as substrates at ratios of 100:0, 75:25, 50:50, 25:75 and 0:100, based on wet weight basis (w/w). For each digester, the solids retention times (SRT) were 20 days. The organic loading and volatile solids loading were between 1.3-2.2 kg chemical oxygen demand (COD)/m3/day and 0.9-1.5 kg/m3/day, respectively. The digester fed with brewery sludge as co-substrate yielded higher treatment efficiency than sewage sludge alone. The removal efficiencies measured in terms of soluble chemical oxygen demand (SCOD) and total chemical oxygen demands (TCOD) ranged from 40% to 75% and 22% to 35%, respectively. Higher SCOD and TCOD removal efficiencies were obtained when higher fractions of brewery sludge was added to the substrate mixture. Removal efficiency was lowest for sewage sludge alone. Measured volatile solid (VS) reduction ranged from 15% to 20%. Adding a higher fraction of brewery sludge to the mixture increased the VS reduction percentage. The biogas production and methane yield also increased with increase in brewery sludge addition to the digester mixture. The methane content present in biogas of each digester exceeded 70% indicating the system was functioning as an anaerobic process. Likewise the ratio of brewery sewage influenced not only the treatment efficiency but also improved quality of treated sludge by lowering number of pathogen (less than 2 MPN/g of dried sludge) and maintaining a high nutrient concentration of nitrogen (N) 3.2-4.2%, phosphorus (P) 1.9-3.2% and potassium (K) 0.95-0.96%. The heavy metals, chromium (Cr) and copper (Cu) remaining in digested sludge were present at relatively high levels (Cr 1,849-4,230 and Cu 930-2,526 mg/kg dried sludge). The metals were present as organic matter-bound and sulfide-bound fractions that are not soluble and available. The digested sludge could be safely applied to soil as a plant nutrient source, without fecal coliforms or heavy metals risk. A sludge mixture ratio of 25:75 (sewage:brewery), which generated the higher nutrient concentrations (N=4.22%, P=3.20% and K=0.95%), biogas production and treatment efficiency meet the Bangkok Metropolitan Administration (BMA) safety guidelines required for agricultural application. Biogas production and methane at the 25:75 ratio (sewage:brewery) yielded highest amount of VSremoved (0.65 m3/kg) and CODremoved (220 L/kg), respectively. PMID:17558772

Pecharaply, Athapol; Parkpian, Preeda; Annachhatre, Ajit P; Jugsujinda, Aroon

2007-06-01

412

TOKOPS: Tokamak Reactor Operations Study: The influence of reactor operations on the design and performance of tokamaks with solid-breeder blankets: Final report  

SciTech Connect

Reactor system operation and procedures have a profound impact on the conception and design of power plants. These issues are studied here using a model tokamak system employing a solid-breeder blanket. The model blanket is one which has evolved from the STARFIRE and BCSS studies. The reactor parameters are similar to those characterizing near-term fusion engineering reactors such as INTOR or NET (Next European Tokamak). Plasma startup, burn analysis, and methods for operation at various levels of output power are studied. A critical, and complicating, element is found to be the self-consistent electromagnetic response of the system, including the presence of the blanket and the resulting forces and loadings. Fractional power operation, and the strategy for burn control, is found to vary depending on the scaling law for energy confinement, and an extensive study is reported. Full-power reactor operation is at a neutron wall loading pf 5 MW/m/sup 2/ and a surface heat flux of 1 MW/m/sup 2/. The blanket is a pressurized steel module with bare beryllium rods and low-activation HT-9-(9-C-) clad LiAlO/sub 2/ rods. The helium coolant pressure is 5 MPa, entering the module at 297/sup 0/C and exiting at 550/sup 0/C. The system power output is rated at 1000 MW(e). In this report, we present our findings on various operational scenarios and their impact on system design. We first start with the salient aspects of operational physics. Time-dependent analyses of the blanket and balance of plant are then presented. Separate abstracts are included for each chapter.

Conn, R.W.; Ghoniem, N.M.; Firestone, M.A. (eds.)

1986-09-01

413

Biomass-to-electricity: analysis and optimization of the complete pathway steam explosion--enzymatic hydrolysis--anaerobic digestion with ICE vs SOFC as biogas users.  

PubMed

The paper deals with the energy analysis and optimization of a complete biomass-to-electricity energy pathway, starting from raw biomass towards the production of renewable electricity. The first step (biomass-to-biogas) is based on a real pilot plant located in Environment Park S.p.A. (Torino, Italy) with three main steps ((1) impregnation; (2) steam explosion; (3) enzymatic hydrolysis), completed by a two-step anaerobic fermentation. In the second step (biogas-to-electricity), the paper considers two technologies: internal combustion engines and a stack of solid oxide fuel cells. First, the complete pathway has been modeled and validated through experimental data. After, the model has been used for an analysis and optimization of the complete thermo-chemical and biological process, with the objective function of maximization of the energy balance at minimum consumption. The comparison between ICE and SOFC shows the better performance of the integrated plants based on SOFC. PMID:22940353

Santarelli, M; Barra, S; Sagnelli, F; Zitella, P

2012-11-01

414

The research on new type fast burning systems for biogas engine  

SciTech Connect

In order to meet the demands of energy supply and environmental protection, the large and medium-sized biogas engineering are developed quickly. The biogas engines are also beginning to be developed in China. However, the problems of afterburning and short lifespan of spark ignited biogas engine have not been solved. According to the fast burning theory in gas engines, the authors developed four kinds of new combustion systems which could promote the fast burning of mixture gas and gained good effects. This paper discusses in detail the structural features and experimental results of one combustion system: the Fan shaped combustion chamber.

Xia, L.; Zheng, B.; Chen, Z. [Zhejiang Univ., Hangzhou (China). Dept. of Energy Engineering

1996-12-31

415

Prediction of trace compounds in biogas from anaerobic digestion using the MATLAB Neural Network Toolbox  

Microsoft Academic Search

Abstract The outlook,to apply the highly energetic biogas,from,anaerobic,digestion into fuel cells will result in a significantly higher electrical efficiency and,can contribute,to an increase of renewable,energy,production. The practical bottleneck is the fuel cell poisoning,caused,by several gaseous,trace compounds,like hydrogen,sulfide and,ammonia.,Hence artificial neural networks,were developed,to predict these trace compounds.,The experiments,concluded,that ammonia,in biogas,can indeed,be present up to 93 ppm. Hydrogen,sulfide and ammonia,concentrations,in biogas were

David P. B. T. B. Strik; Alexander M. Domnanovich; Loredana Zani; Rudolf Braun; Peter Holubar

2005-01-01

416

Bioenergy systems report. April 1984: innovations in biogas systems and technology  

SciTech Connect

A comprehensive review of recent innovations in the design and operation of biogas systems is presented. The report contains information on about sixty distinct designs for biogas plants. These include plants designed for use by individual families, larger farm plants, plants used for the digestion of agroindustrial residues, and plants producing or recovering biogas from human wastes and residues. Some have been designed for use in developing countries; others have been used primarily in developed countries but may involve design elements that could be utilized in developing countries.

Mahin, D.B.

1984-04-01

417

Recycled paper mill effluent treatment in a modified anaerobic baffled reactor: start-up and steady-state performance.  

PubMed

Start-up period is considered to be the most unstable and difficult stage in anaerobic process and usually takes a long time due to slow-degree adaptation of anaerobic microorganisms. In order to achieve a shorter start-up period, a novel modified anaerobic baffled reactor (MABR) has been developed in this study, where each modified baffle has its own characteristics (form/shape) to facilitate a treatment ofrecycled paper mill effluent (RPME). The results ofphysico-chemical characteristics showed that effluent from recycled paper mill consisted of 4328mgL-1 chemical oxygen demand (COD), 669mg L-1 biochemical oxygen demand and 501mg L-1 volatile fatty acid. It also consisted of variety of heavy metals such as zinc, magnesium, iron and nickel at concentrations of 1.39, 12.19, 2.39 and 0.72 mgL-1, respectively. Performance of MABR during the start-up period showed that methane production reached 34.7% with COD removal of 85% at steady state. The result indicates that MABR was successfully operated during the start-up period in treating RPME within a period of less than 30 days. PMID:24600868

Hassana, Siti Roshayu; Zwaina, Haider M; Zamana, Nastaein Qamaruz; Dahlanb, Irvan

2014-01-01

418

Aerobic methane oxidation coupled to denitrification in a membrane biofilm reactor: treatment performance and the effect of oxygen ventilation.  

PubMed

Aerobic methane-oxidation coupled to denitrification (AME-D) process was successfully achieved in a membrane biofilm reactor (MBfR). PVDF membrane was employed to supply the methane and oxygen for biofilm, which was coexistence of methanotrophs and denitrifier. With a feeding NO3(-)-N of 30 mg/L, up to 97% nitrate could be removed stably. The oxygen ventilation modes impacted the denitrification performance remarkably, resulting in different nitrate removal efficiencies and biofilm microorganism distribution. The biofilm sludge showed a high resistance to the DO inhibition, mainly due to the co-existing methanotroph being capable of utilizing oxygen perferentially within biofilm, and create an anoxic micro-environment. The denitrification of both nitrate and nitrite by biofilm sludge conformed to the Monod equation, and the maximum specific nitrate utilization rate (k) ranged from 1.55 to 1.78 NO3(-)-N/g VSS-d. The research findings should be significant to understand the considerable potential of MBfR as a bioprocess for denitrification. PMID:23582221

Sun, Fei-yun; Dong, Wen-yi; Shao, Ming-fei; Lv, Xiao-mei; Li, Ji; Peng, Liang-yu; Wang, Hong-jie

2013-10-01

419

Deployment of a Suite of High-Performance Computational Tools for Multi-scale Multi-physics Simulation of Generation IV Reactors  

SciTech Connect

The overall objective of this project has been to deploy advanced simulation capabilities for next generation reactor systems utilizing newly available, high-performance computing facilities. The approach includes the following major components: The development of new simulation capabilities using state-of-the-art computer codes of different scales: molecular dynamics (MD) level, DNS (FronTier and PHASTA) and CFD (NPHASE-CMFD); The development of advanced numerical solvers for large-size computational problems; The deployment of a multiple-code computational platform for multiscale simulations of gas/liquid two-phase flow during reactor transients and accidents; and Application of the new computational methodology to study the progression of loss-of-flow accident in sodium fast reactor (SFR).

Michael Z. Podowski

2013-01-03

420

NIRS-aided monitoring and prediction of biogas yields from maize silage at a full-scale biogas plant applying lumped kinetics.  

PubMed

The aim of this study was to apply near-infrared spectroscopy (NIRS), available biogas plant data and lumped degradation kinetics to predict biogas production (BPr) of maize silage. A full-scale agricultural biogas plant was equipped with NIRS-metrology at the feeding station. Continuously NIR-spectra were collected for 520 d. Substrate samples were analyzed by means of feedstuff analysis. Biogas potential of the samples was calculated from the laboratory analysis results and for a sample-subset practically assessed by "Hohenheim biogas tests". NIRS-regression-models for all mentioned parameters were calibrated. Continuously gathered spectra, NIRS-models, actual plant-feeding data and degradation kinetics were used to calculate time-series of theoretically expectable BPr. Results were validated against measured gas quantity. Determination coefficients between calculated and measured BPr were up to 58.2%. This outcome was mainly due to the positive correlation between BPr and input amount since the substrate was very homogeneous. The use of NIRS seems more promising for plants with stronger substrate heterogeneity. PMID:22055101

Jacobi, H Fabian; Ohl, Susanne; Thiessen, Eiko; Hartung, Eberhard

2012-01-01

421

Biogas production from anaerobic digestion of Spirulina maxima algal biomass  

SciTech Connect

The semimicroscopic blue-green alga Spirulina maxima makes an ideal substrate for anaerobic digestion because it is easy to harvest, it can use carbon dioxide from the atmosphere as its carbon source, and its fermentability is higher than that of other small algae. Digestion experiments demonstrated that S. maxima can serve as the sole nutrient for biogas production and that municipal sewage sludge, when adapted to this new substrate, is very stable. During semicontinuous daily-fed trials under non-optimal conditions at an 0.06 lb volatile solids (VS)/ft/sup 3/ (0.97 kg VS/m/sup 3/) loading rate, 33-day retention time, and 86/sup 0/F (30/sup 0/C) digestion temperature, the daily methane yield was 4.2 CF/lb (0.26 m/sup 3//kg) VS added, which represents 47% of the maximum theoretical yield. Studies on optimizing the process are underway.

Samson, R.; LeDuy, A.

1982-08-01

422

Naval Reactors Prime Contractor Team (NRPCT) Experiences and Considerations With Irradiation Test Performance in an International Environment  

SciTech Connect

This letter forwards a compilation of knowledge gained regarding international interactions and issues associated with Project Prometheus. The following topics are discussed herein: (1) Assessment of international fast reactor capability and availability; (2) Japanese fast reactor (JOYO) contracting strategy; (3) NRPCT/Program Office international contract follow; (4) Completion of the Japan Atomic Energy Agency (JAEA)/Pacific Northwest National Laboratory (PNNL) contract for manufacture of reactor test components; (5) US/Japanese Departmental interactions and required Treaties and Agreements; and (6) Non-technical details--interactions and considerations.

MH Lane

2006-02-15

423

Biogas Production at Low Temperatures. Interim Report Concerning Propagation and Activity Tests of Anaerobic Psychrophilic Bacteria.  

National Technical Information Service (NTIS)

Literature concerning biogas production at low temperatures was received, showing that depending on dry matter content of added substrate psychophilic or mesophilic bacteria grow; U.A.S.B. filters are able to reduce low concentration waste water at temper...

N. Oestergaard

1985-01-01

424

Comparison of biogas production from wild and cultivated varieties of reed canary grass.  

PubMed

The chemical composition and efficiency of biogas production in the methane fermentation process of silages of wild and cultivated varieties of reed canary grass were compared. An attempt was made to answer the question on how the habitat and the way of utilization of plants affect chemical composition and biogas yield. Physicochemical properties such as dry matter, organic dry matter, protein, fat, crude fiber fraction, macro- and microelements content were considered. The anaerobic digestion process and FTIR analysis were also carried out. The results showed that the two varieties differ essentially in their physical and chemical properties. The cultivated variety was characterized by higher biogas yield (406Ndm(3)kg(-1) VS) than the wild one (120Ndm(3)kg(-1) VS). This was probably related to the chemical composition of plants, especially the high content of indigestible crude fiber fractions and ash. These components could reduce biogas quantity and quality. PMID:24518439

Oleszek, Marta; Król, Aleksandra; Tys, Jerzy; Matyka, Mariusz; Kulik, Mariusz

2014-03-01

425

COUPLED ANAEROBIC DIGESTER: WETLAND SYSTEM FOR DAIRY WASTE AND STORMWATER TREATMENT WITH BIOGAS PRODUCTION  

EPA Science Inventory

By coupling wastewater treatment and biogas production, the proposed design will increase sustainability by (i) decreasing pollution of waters, fields, and ecosystems, and (ii) providing a return-on-investment for wastewater and stormwater treatment, (iii) decreasing costs ...

426

Diversity and variability of methanogens during the shift from mesophilic to thermohilic conditions while biogas production.  

PubMed

Anaerobic digestion (AD) is the most popular path of organic waste disposal. It is often used in wastewater treatment plants for excessive sludge removal. Methanogenic fermentation had usually been performed under mesophilic conditions, but in the past few years the thermophilic processes have become more popular due to economics and sludge sanitation. Methanogens, the group of microorganisms responsible for methane production, are thought to be sensitive to temperature change and it has already been proven that the communities performing methanogenesis under mesophilic and thermophilic conditions differ. But in most cases the research performed on methanogen diversity and changeability was undertaken in two separate anaerobic chambers for meso- and thermophilic conditions. It is also known that there is a group of microorganisms performing AD which are insensitive to temperature. Also the linkage between digester performance and its microbial content and community changeability is still not fully understood. That is why in this experiment we analyzed the bacterial community performing methanogenesis in a pilot scale anaerobic chamber during the shift from mesophilic to thermophilic conditions to point at the group of temperature tolerant microorganisms and their performance. The research was performed with PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis). It occurred that the community biodiversity decreased together with a temperature increase. The changes were coherent for both the total bacteria community and methanogens. These bacterial shifts were also convergent with biogas production-it decreased in the beginning of the thermophilic phase with the bacterial biodiversity decrease and increased when the community seemed to be restored. DGGE results suggest that among a wide variety of microorganisms involved in AD there is a GC-rich group relatively insensitive towards temperature change, able to adapt quickly to shifts in temperature and perform AD effectively. The studies of this microbial group could be a step forward in developing more efficient anaerobic digestion technology. PMID:25218710

Ziembi?ska-Buczy?ska, A; Banach, A; Bacza, T; Pieczykolan, M

2014-12-01

427

Performance of a 24,000 liter, multi stage Continuous Stirred Reactor Separator (CSRS) for ethanol from sugars, and application of the CSRS towards cellulosics  

SciTech Connect

A pilot scale 24,000 liter, 4 stage reactor has been built, installed, and is undergoing performance trials. This Continuous Stirred Reactor Separator (CSRS) allows the continuous production and separation of ethanol from the fermentation broth using stirred reactor stages crossed with gas stripping of the overflow broth. The gas stripping of ethanol speeds fermentation rates by reducing the ethanol concentration on the lower stages. This CSRS is designed to have ethanol recovered from the exiting vapors using a solvent absorption column, after which the ethanol will be recovered from the solvent. The CSRS was installed in March of 1995, and has been operated as a continuous cascade type fermenter (without separation). The reactor has been running continuously since September of 1995 with feed rates varying between 0 (when feed tanks are exhausted) to 20 LPM. Yeast densities of a flocculent yeast have been measured at up to 50% cell settling volume. Preliminary work on biomass conversion to ethanol using the CSRS is being performed. Pretreatment studies, xylose fermentations, and SSF of cellulose have been started. It is planned to operate a two section CSRS for the successive conversion of hemicellulose/xylans followed by cellulose/glucans to ethanol.

Dale, M.C. [Bio-Process Innovation Inc., West Lafayette, IN (United States); Gribb, D.; Lehman, R.L. [Permeate Refining Inc., Cedar Rapids, IA (United States)

1996-12-31

428

Integrated fuel performance and thermal-hydraulic sub-channel models for analysis of sodium fast reactors  

E-print Network

Sodium Fast Reactors (SFR) show promise as an effective way to produce clean safe nuclear power while properly managing the fuel cycle. Accurate computer modeling is an important step in the design and eventual licensing ...

Fricano, Joseph William

2012-01-01

429

Exergy analysis of the demonstration plant for co-production of hydrogen and benzene from biogas  

Microsoft Academic Search

The dehydro-aromatization reaction of methane is one of the methods to utilize biogas and co-produces hydrogen and benzene. To demonstrate the industrial co-production of hydrogen and benzene from biogas, we constructed a demonstration plant. The purpose of this study is to evaluate the feasibility of the demonstration plant, which can co-produce 134Nm3\\/day of hydrogen and 8.6L\\/day of benzene from 200Nm3\\/day

Yukoh Shudo; Takashi Ohkubo; Yoshiaki Hideshima; Tomohiro Akiyama

2009-01-01

430

Environmental systems analysis of biogas systems—Part I: Fuel-cycle emissions  

Microsoft Academic Search

Fuel-cycle emissions of carbon dioxide (CO2), carbon oxide (CO), nitrogen oxides (NOx), sulphur dioxide (SO2), hydrocarbons (HC), methane (CH4), and particles are analysed from a life-cycle perspective for different biogas systems based on six different raw materials. The gas is produced in large- or farm-scale biogas plants, and is used in boilers for heat production, in turbines for co-generation of

Pål Börjesson; Maria Berglund

2006-01-01