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1

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

2

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

PubMed

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

Ramakrishnan, Anushuya; Surampalli, Rao Y

2013-02-01

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

Performance of biogas plants of different designs  

SciTech Connect

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

Not Available

1981-08-01

5

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

Microsoft Academic Search

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

Zhiyi DENG; Chaohai WEI; Xiufeng ZHOU

2008-01-01

6

Impacts of biogas plant performance factors on total substrate costs  

Microsoft Academic Search

Substrate costs in biogas production can be reduced by up to 30% by adjusting logistic capacity to chopper performance. The aim of this article is to analyze the impacts of biogas plant performance factors on total substrate costs for two common biogas plant sizes in Austria. A nonlinear optimization model is built to analyze the impact of alternative substrates, machinery

B. Stürmer; E. Schmid; M. W. Eder

2011-01-01

7

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

8

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

9

Performance Evaluation of Janata and Deenbandhu Biogas Plants  

Microsoft Academic Search

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 rated capacity of the plant, but it also produced more gas per unit

ANJAN K. KALIA; SARBJIT S. KANWAR

1996-01-01

10

Microbial analysis in biogas reactors suffering by foaming incidents.  

PubMed

Foam formation can lead to total failure of digestion process in biogas plants. In the present study, possible correlation between foaming and the presence of specific microorganisms in biogas reactors was elucidated. The microbial ecology of continuous fed digesters overloaded with proteins, lipids and carbohydrates before and after foaming incidents was characterized using 16S rRNA gene sequencing. Moreover, the microbial diversity between the liquid and foaming layer was assessed. A number of genera that are known to produce biosurfactants, contain mycolic acid in their cell wall, or decrease the surface tension of the media, increased their relative abundance after foam formation. Finally, a microorganism similar to widely known foaming bacteria (Nocardia and Desulfotomaculum) was found to increase its relative abundance in all reactors once foam was observed, regardless of the used substrate. These findings suggest that foaming and specific microorganisms might have direct association which requires to be further investigated. PMID:24968108

Kougias, Panagiotis G; De Francisci, Davide; Treu, Laura; Campanaro, Stefano; Angelidaki, Irini

2014-09-01

11

Foam suppression in overloaded manure-based biogas reactors using antifoaming agents.  

PubMed

Foam control is an imperative need in biogas plants, as foaming is a major operational problem. In the present study, the effect of oils (rapeseed oil, oleic acid, and octanoic acid) and tributylphosphate on foam reduction and process performance in batch and continuous manure-based biogas reactors was investigated. The compounds were tested in dosages of 0.05%, 0.1% and 0.5% v/vfeed. The results showed that rapeseed oil was most efficient to suppress foam at the dosage of 0.05% and 0.1% v/vfeed, while octanoic acid was most efficient to suppress foam at dosage of 0.5% v/vfeed. Moreover, the addition of rapeseed oil also increased methane yield. In contrast, tributylphosphate, which was very efficient antifoam, was found to be inhibitory to the biogas process. PMID:24365741

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

2014-02-01

12

Microbial community analyses in biogas reactors by molecular methods.  

PubMed

Successful biogas production is based on stable or adaptable microbial community structure and activity which depends on type of substrate used and several physico-chemical conditions in the bioreactor. Monitoring those and the dynamics of microbiota is important for planning and optimizing the biogas process, avoiding critical points and reaching the maximum methane yield. Methanogens are extremely difficult to study with culture-based methods. Molecular methods for microbial community structure analysis in biogas reactors, which offer qualitative and quantitative information on bacterial and archaeal species and their microbial community changes, and causes for process instability are surveyed in this review. For comparative studies semi-quantitative, rapid and cheap techniques like T-RFLP, DGGE and TGGE are used. More laborious and expensive techniques with high-throughput like semi-quantitative FISH and DNA microarrays and also quantitative techniques like qPCR and sequencing are used for phylogenetic analysis. Technique type adequacy for certain study depends on what information is needed and on several advantages and disadvantages every technique possesses. PMID:23878927

cater, Masa; Fanedl, Lijana; Logar, Romana Marinsek

2013-01-01

13

Control of an anaerobic reactor towards maximum biogas production  

Microsoft Academic Search

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

J. Liu; G. Olsson; B. Mattiasson

14

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

PubMed Central

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

Westerholm, Maria; Leven, Lotta

2012-01-01

15

Antifoaming effect of chemical compounds in manure biogas reactors.  

PubMed

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

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

2013-10-15

16

Acetate conversion in anaerobic biogas reactors: traditional and molecular tools for studying this important group of anaerobic microorganisms.  

PubMed

Different methods were applied to study the role of aceticlastic methanogens in biogas reactors treating solid waste and wastewater. We used traditional microbiological methods, immunological and 16S rRNA ribosomal probes for detection of the methanogens. Using this approach we identified the methanogenic spp. and their activity. In biofilm systems, such as the UASB reactors the presence of the two aceticlastic methanogens could be correlated to the difference in the kinetic properties of the two species. In biogas reactors treating solid wastes, such as manure or mixture of manure and organic industrial waste, only Methanosarcina spp. were identified. Methanosarcina spp. isolated from different plants had different kinetics depending on their origin. Relating the reactor performance data to measurement of the activity by conventional microbiological methods gave a good indication of the microbial status of specific trophic groups. 16S rRNA probing confirmed these observations and gave a more detailed picture of the microbial groups present. PMID:11587438

Schmidt, J E; Mladenovska, Z; Lange, M; Ahring, B K

2000-01-01

17

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

18

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

19

Studies in biogas technology. Part I. Performance of a conventional biogas plant  

Microsoft Academic Search

This paper gives an account of a conventional 5.66 m3\\/day (200 cubic ft\\/day) biogas plant which has been instrumented, operated and monitored for 2 1\\/2 years. The observations\\u000a regarding input to the plant, sludge and biogas outputs, and conditions inside the digester, have been described. Three salient\\u000a features stand out. First, the observed average daily gas yield is much less

P. Rajabapaiah; K. V. Ramanayya; S. R. Mohan; Amulya Kumar N. Reddy

1979-01-01

20

Where does the removal of H2S from biogas occur in microaerobic reactors?  

PubMed

In order to maximise the efficiency of biogas desulphurisation and reduce the oxygen cost during microaerobic digestion, it is essential to know how the process occurs. For this purpose, a reactor with a total volume of 266L, treating 10L/d of sewage sludge, was operated with 25.0L and without headspace. Under anaerobic conditions, the H2S concentration in the biogas varied between 0.21 and 0.38%v/v. Next, O2 was supplied from the bottom of the reactor. At 0.25-0.30 NLO2/Lfed, the biogas was entirely desulphurised, and its O2 content remained below 1.03%v/v, when the digester had 25.0L of gas space. However, with almost no headspace, the H2S content in the biogas fluctuated from 0.08 to 0.21%v/v, while the average O2 concentration was 1.66%v/v. The removed H2S accumulated in the outlet pipe of the biogas in the form of S(0) due to the insufficient headspace. PMID:24907574

Ramos, I; Peña, M; Fdz-Polanco, M

2014-08-01

21

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

22

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

Microsoft Academic Search

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

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

2009-01-01

23

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

24

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

25

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

26

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

PubMed Central

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

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

2012-01-01

27

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

28

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

29

Biogas production from banana stem waste: optimisation of 10 l sequencing batch reactor  

Microsoft Academic Search

The performance of biogas production using banana stem waste in anaerobic system was investigated. Mixed culture for this study was from banana plantation soil and acclimatized in anaerobic condition. The performance was tested under the conditions of various temperatures (26degC-40degC), organic loading rates (OLR) (0.4 g TS\\/l.d-2 gTS\\/l.d), and hydraulic retention times (HRT) (3 d-20 d). Conditions for temperature, OLR

N. Zainol; J. Salihon; R. Abdul-Rahman

2008-01-01

30

Hollow fiber membrane based H? diffusion for efficient in situ biogas upgrading in an anaerobic reactor.  

PubMed

Bubbleless gas transfer through a hollow fiber membrane (HFM) module was used to supply H2 to an anaerobic reactor for in situ biogas upgrading, and it creates a novel system that could achieve a CH4 content higher than 90 % in the biogas. The increase of CH4 content and pH, and the decrease of bicarbonate concentration were related with the increase of the H2 flow rate. The CH4 content increased from 78.4 % to 90.2 % with the increase of the H2 flow rate from 930 to 1,440 ml/(l ?day), while the pH in the reactor remained below 8.0. An even higher CH4 content (96.1 %) was achieved when the H2 flow rate was increased to 1,760 ml/(l? day); however, the pH increased to around 8.3 due to bicarbonate consumption which hampered the anaerobic process. The biofilm formed on the HFM was found not to be beneficial for the process since it increased the resistance of H2 diffusion to the liquid. The study also demonstrated that the biofilm formed on the membrane only contributed 22-36 % to the H2 consumption, while most of the H2 was consumed by the microorganisms in the liquid phase. PMID:23494624

Luo, Gang; Angelidaki, Irini

2013-04-01

31

Experimental comparison of MCFC performance using three different biogas types and methane  

NASA Astrophysics Data System (ADS)

Biogas recovery is an environmentally friendly and cost-effective practice that is getting consensus in both the scientific and industrial community, as the growing number of projects demonstrate. The use of fuel cells as energy conversion systems increases the conversion efficiency, as well as the environmental benefits. Molten carbonate fuel cells (MCFC) operate at a temperature of about 650 °C, thus presenting a high fuel flexibility, compared to low temperature fuel cells. Aim of the present study is to compare the performance of an MCFC single cell, fuelled with different biogas types as well as methane. The biogases considered are derived from the following processes: (1) steam gasification in an entrained flow gasifier; (2) steam gasification in a duel interconnect fluidized bed gasifier; (3) biogas from an anaerobic digestion process. The performances are evaluated for different fuel utilization and current densities. The results are an essential starting point for a complete system design and demonstration.

Bove, Roberto; Lunghi, Piero

32

Assessing the performance of biogas plants with multi-criteria and data envelopment analysis  

Microsoft Academic Search

This paper performs an assessment of 41 agricultural biogas plants located in Austria to determine their relative performance in terms of economic, environmental, and social criteria and corresponding indicators. The comparison of these renewable energy conversion plants is based on two complementary analyses. Data envelopment analysis (DEA) was conducted to provide measures of radial efficiency relative to the observed frontier

Reinhard Madlener; Carlos Henggeler Antunes; Luis C. Dias

2009-01-01

33

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

34

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

35

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

PubMed

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

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

2010-04-01

36

Assessment of a biogas-generating microbial community in a pilot-scale anaerobic reactor.  

PubMed

In this work bacteria and methanogenic archaea utilizing agricultural wastes in a pilot-scale biogas reactor were examined using sequencing and terminal restriction fragment length polymorphism analysis. Based on the analyses of 16S rRNA genes, Clostridia represented the most diverse group in the digester. Of the Clostridia, unclassified Clostridiales and the members of the genera Anaerotruncus and Tissierella were detected at high abundances. The representatives of the bacterial phyla Bacteroidetes and Proteobacteria were also defined, but in minor proportions, and were assigned to non-dominant communities. Within the phylum Euryarchaeota, the members of the orders Methanosarcinales and Methanomicrobiales were found at high levels. Methanogenic archaea were analyzed using both 16S rRNA and mcrA genes. Actually good results were received using both approaches; however, the rRNA gene method missed the non-dominant order Methanobacteriales. PMID:24418257

Ziganshina, Elvira E; Bagmanova, Alsu R; Khilyas, Irina V; Ziganshin, Ayrat M

2014-06-01

37

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

Microsoft Academic Search

A full-scale jet biogas internal loop anaerobic fluidized bed (JBILAFB) reactor, which requires low energy input and allows\\u000a enhanced mass transfer, was constructed for the treatment of food processing wastewater. This reactor has an active volume\\u000a of 798 m3 and can treat 33.3 m3 wastewater per hour. After pre-treating the raw wastewater by settling, oil separating and coagulation-air floating processes,\\u000a the reactor

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

2011-01-01

38

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

PubMed

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

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

2009-12-01

39

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

40

The headspace of microaerobic reactors: Sulphide-oxidising population and the impact of cleaning on the efficiency of biogas desulphurisation.  

PubMed

O2-limiting/microaerobic conditions were applied in order to control the H2S content of biogas. The S(0)-rich deposits found all over the headspace of two pilot reactors (R1 and R2) as a result of operating under such conditions for 7 and 15months (respectively) were sampled and removed. After restarting micro-oxygenation, H2S-free biogas was rapidly obtained, and the O2 demand of R2 decreased. This highlighted the need for a cleaning interval of less than 14months in order to minimise the micro-oxygenation cost. The H2S removed from R2 after approximately 1month was recovered from its headspace as S(0), thus indicating that the biogas desulphurisation did not take place at the liquid interface. Denaturing gradient gel electrophoresis indicated that the composition, species richness and size of the sulphide-oxidising bacteria population depended on the location, and, more specifically, moisture availability, and indicated increasing species richness over time. Additionally, a possible succession was estimated. PMID:24583216

Ramos, I; Pérez, R; Fdz-Polanco, M

2014-04-01

41

Neural-fuzzy control system application for monitoring process response and control of anaerobic hybrid reactor in wastewater treatment and biogas production.  

PubMed

Based on the developed neural-fuzzy control system for anaerobic hybrid reactor (AHR) in wastewater treatment and biogas production, the neural network with backpropagation algorithm for prediction of the variables pH, alkalinity (Alk) and total volatile acids (TVA) at present day time t was used as input data for the fuzzy logic to calculate the influent feed flow rate that was applied to control and monitor the process response at different operations in the initial, overload influent feeding and the recovery phases. In all three phases, this neural-fuzzy control system showed great potential to control AHR in high stability and performance and quick response. Although in the overloading operation phase II with two fold calculating influent flow rate together with a two fold organic loading rate (OLR), this control system had rapid response and was sensitive to the intended overload. When the influent feeding rate was followed by the calculation of control system in the initial operation phase I and the recovery operation phase III, it was found that the neural-fuzzy control system application was capable of controlling the AHR in a good manner with the pH close to 7, TVA/Alk < 0.4 and COD removal > 80% with biogas and methane yields at 0.45 and 0.30 m3/kg COD removed. PMID:21462705

Waewsak, Chaiwat; Nopharatana, Annop; Chaiprasert, Pawinee

2010-01-01

42

An Application of Solar Energy Storage in the Gas: Solar Heated Biogas Plants  

Microsoft Academic Search

Temperature is an important factor that may affect the performance of anaerobic digestion. Therefore, biogas plants without heating system work only in warmer regions for the whole year. In regions with extreme temperature variations, for instance in Turkey, the biogas plant should be built with heating system. One of the methods is to use solar energy to increase the reactor

G. Kocar; A. Eryasar

2007-01-01

43

Heating of a biogas reactor using a solar energy system with temperature control unit  

Microsoft Academic Search

Maintaining a temperature level of about 40°C, the optimum temperature for mesophilic bacteria’s growth and activity, is crucial for obtaining the best results with respect to biogas production. This study investigates the utilization of solar energy for heating a bioreactor that was already developed at our laboratory and is currently in operation. For purposes of this study, a solar collector

T. M. Alkhamis; R. El-khazali; M. M. Kablan; M. A. Alhusein

2000-01-01

44

Influence of CO2 scrubbing from biogas on the treatment performance of a high rate algal pond.  

PubMed

Biogas produced by anaerobic treatment of wastewater can be collected and used for power generation. However, the biogas may require scrubbing to prevent corrosion by H2S and to improve engine efficiency by reducing the CO2 content. HRAP can be used to scrub biogas during the daytime when they are carbon-limited and have high pH. This study investigates the influence of the carbon dioxide addition from biogas scrubbing on high rate algal pond wastewater treatment performance (in terms of BOD, NH4-N, DRP and E. coli removal) and algal production (growth and species composition). Batch culture experiments were conducted in laboratory microcosms (2 L) and outside mesocosms (20 L). Results indicate that CO2 addition and reduced culture pH increased algal production and nutrient assimilation, decreased high pH mediated nutrient removal processes (phosphate precipitation and ammonia volatilisation), but had little influence on the ability of the culture to remove filtered BODs. Disinfection, as indicated by E.coli removal; was reduced, however, further research on virus removal, which is not affected by culture pH, is required. These preliminary findings indicate the potential to scrub C02 from biogas using high rate pond water without decreasing the effectiveness of wastewater treatment and enabling increased recovery of wastewater nutrients as algal biomass. PMID:17591212

Heubeck, S; Craggs, R J; Shilton, A

2007-01-01

45

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

46

Computer model for performance prediction and optimization of unheated biogas plant  

Microsoft Academic Search

A mathematical model of an unheated biogas plant described in this paper can be used to predict biogas generation at any given geographical location by using laboratory experimental data of methane gas generation at different values of temperature and retention time. So, this model obviates the need for repeating field experiments at different geographical locations. The introduction of new concepts

Parm Pal Singh; B. S. Ghuman; N. S. Grewal

1998-01-01

47

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

48

Ultrasound assisted biogas production from landfill leachate.  

PubMed

The aim of this study is to increase biogas production and methane yield from landfill leachate in anaerobic batch reactors by using low frequency ultrasound as a pretreatment step. In the first part of the study, optimum conditions for solubilization of organic matter in leachate samples were investigated using various sonication durations at an ultrasound frequency of 20kHz. The level of organic matter solubilization during ultrasonic pretreatment experiments was determined by calculating the ratio of soluble chemical oxygen demand (sCOD) to total chemical oxygen demand (tCOD). The sCOD/tCOD ratio was increased from 47% in raw leachate to 63% after 45min sonication at 600W/l. Non-parametric Friedman's test indicated that ultrasonic pretreatment has a significant effect on sCOD parameter for leachate (p<0.05). In the second part of the study, anaerobic batch reactors were operated for both ultrasonically pretreated and untreated landfill leachate samples in order to assess the effect of sonication on biogas and methane production rate. In anaerobic batch reactor feed with ultrasonically pretreated leachate, 40% more biogas was obtained compared to the control reactor. For statistical analysis, Mann-Whitney U test was performed to compare biogas and methane production rates for raw and pretreated leachate samples and it has been found that ultrasonic pretreatment significantly enhanced biogas and methane production rates from leachate (p<0.05) in anaerobic batch reactors. The overall results showed that low frequency ultrasound pretreatment can be potentially used for wastewater management especially with integration of anaerobic processes. PMID:24709441

Oz, Nilgün Ayman; Yarimtepe, Canan Can

2014-07-01

49

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

PubMed Central

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

2013-01-01

50

Biogas technology in Pakistan.  

National Technical Information Service (NTIS)

Although biomethanation is a mature technology, its implementation is only partly a success in Pakistan. Biogas plants on family farms can be economical but are seldom so in Pakistan. Either the investment cost has been high or satisfactory performance of...

M. Ahmed

1997-01-01

51

Biogasification of biowaste and sewage sludge – Measurement of biogas quality  

Microsoft Academic Search

Biogas quality, the presence of some trace components (siloxanes, sulfur compounds, volatile organic compounds, VOCs) in biogas, is in a decisive role when determining the biogas utilization and the purification requirements and equipments. In the present work, the effects of process changes related to reactor loading variations on the concentrations of selected trace compounds in biogas were studied. Source separated

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

52

Performance evaluation of oxygen, air and nitrate for the microaerobic removal of hydrogen sulphide in biogas from sludge digestion.  

PubMed

The removal performance of hydrogen sulphide in severely polluted biogas produced during the anaerobic digestion of sludge was studied by employing pure oxygen, air and nitrate as oxidant reactives supplied to the biodigester. Research was performed in a 200-L digester with an hydraulic retention time (HRT) of ?20 days under mesophilic conditions. The oxygen supply (0.25 N m³/m³ feed) to the bioreactor successfully reduced the hydrogen sulphide content from 15,811 mg/N m³ to less than 400 mg/N m³. The introduction of air (1.27 N m³/m³ feed) removed more than 99% of the hydrogen sulphide content, with a final concentration of ?55 mg/N m³. COD removal, VS reduction and methane yield were not affected under microaerobic conditions; however, methane concentration in the biogas decreased when air was employed as a result of nitrogen dilution. The nitrate addition was not effective for hydrogen sulphide removal in the biogas. PMID:20605444

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

2010-10-01

53

Biogas production from potato-juice, a by-product from potato-starch processing, in upflow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors  

Microsoft Academic Search

In this study, the utilization of potato-juice, the organic by-product from potato-starch processing, for biogas production was investigated in batch assay and in high rate anaerobic reactors. The maximum methane potential of the potato-juice determined by batch assay was 470mL-CH4\\/gVS-added. Anaerobic digestion of potato-juice in an EGSB reactor could obtain a methane yield of 380mL-CH4\\/gVS-added at the organic loading rate

Cheng Fang; Kanokwan Boe; Irini Angelidaki

2011-01-01

54

Biogas production from supernatant of hydrothermally treated municipal sludge by upflow anaerobic sludge blanket reactor  

Microsoft Academic Search

The supernatant of hydrothermally treated sludge was treated by an upflow anaerobic sludge blanket (UASB) reactor for a 550-days running test. The hydrothermal parameter was 170°C for 60min. An mesophilic 8.6L UASB reactor was seeded with floc sludge. The final organic loading rate (OLR) could reach 18kg COD\\/m3d. At the initial stage running for 189days, the feed supernatant was diluted,

Wei Qiao; Chong Peng; Wei Wang; ZhongZhi Zhang

2011-01-01

55

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

56

High performance light water reactor  

Microsoft Academic Search

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

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

2003-01-01

57

Purificazione di un biogas con moduli PRISM MONSANTO: prestazione di un impianto pilota. (Biogas purification with the use of Monsanto PRISM modules: Pilot plant performance).  

National Technical Information Service (NTIS)

Field test results are reported for the up-grading of a biogas, produced by anaerobic digestion of cattle wastes, by using a MONSANTO pilot plant. The unit is based on four PRISM membrane permeators containing polysulfone hollow fibers which allow for the...

L. Bimbi R. Santarossa

1989-01-01

58

Improvement of Biogas Production by Bioaugmentation  

PubMed Central

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

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

2013-01-01

59

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

60

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

PubMed

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

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

2013-11-01

61

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

62

Biogas generation apple pulp.  

PubMed

In view of the pressing problem that appears in our region (Asturias, north of Spain) with the residues from the cider production, it was decided to test this kind of material as a co-substrate joint with slaughterhouse waste in a laboratory unit. The anaerobic digestion of apple pulp was investigated for biogas production. This paper presents the results where apple pulp was co-digested with slaughterhouse waste (pig intestine and bovine stomach content) in a biogas laboratory unit (10 l CSTR reactor). The production of biogas has reached very satisfactory values during the whole test (0.8m(3)kg(-1)OTS), verifying that the process is kept in stable conditions of pH (near 8.0), and the volatile fatty acids was always underneath 3000 mg/l, when the pulp amount was lower than 100g in mesophilic conditions. The fat concentration into the digester remained always below the value that causes inhibition of the methanogenic bacteria, 500 mg/l. Finally, methane concentration (77-80%) and H(2)S concentration (400 ppm) in the biogas, they were similar to those obtained when the test was run out in the absence of apple pulp. The process efficiency with respect to COD removal was high, near 80% of the total COD. Finally, inhibitory effects of methanogenic bacteria were observed when pulp concentration was around 10% in the input material. PMID:19349172

Llaneza Coalla, H; Blanco Fernández, J M; Morís Morán, M A; López Bobo, M R

2009-09-01

63

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

64

Biogas production from potato-juice, a by-product from potato-starch processing, in upflow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors.  

PubMed

In this study, the utilization of potato-juice, the organic by-product from potato-starch processing, for biogas production was investigated in batch assay and in high rate anaerobic reactors. The maximum methane potential of the potato-juice determined by batch assay was 470 mL-CH(4)/gVS-added. Anaerobic digestion of potato-juice in an EGSB reactor could obtain a methane yield of 380 mL-CH(4)/gVS-added at the organic loading rate of 3.2 gCOD/(L-reactor.d). In a UASB reactor, higher organic loading rate of 5.1 gCOD/(L-reactor.d) could be tolerated, however, it resulted in a lower methane yield of 240 mL-CH(4)/gVS-added. The treatment of reactor effluent was also investigated. By acidification with sulfuric acid to pH lower than 5, almost 100% of the ammonia content in the effluent could be retained during the successive up-concentration process step. The reactor effluent could be up-concentrated by evaporation to minimize its volume, and later be utilized as fertilizer. PMID:21450459

Fang, Cheng; Boe, Kanokwan; Angelidaki, Irini

2011-05-01

65

Harvesting biogas from wastewater sludge and food waste  

NASA Astrophysics Data System (ADS)

Wastewater sludge and food waste are good source of biogas. Anaerobic treatment of slude and food waste able to produce biogas which is a potential renewable energy source. This study looks into the potential biogas generation and the effects of temperature on biogas generation. A lab scale reactor was used to simulate the biogas generation. The results show that wastewater sludge able to produced upto 44.82 ml biogas/kg of sludge. When mixed with food waste at a ratio of 30:70 (food waste), the biogas generated were 219.07 ml/kg of waste. Anaerobic of food waste alone produced biogas amount to 59.75 ml/kg of food waste. Anaerobic treatment also reduces the volume of waste. The effect of temperature shows that higher temperature produces more biogas than lower temperature.

Chua, K. H.; Cheah, W. L.; Tan, C. F.; Leong, Y. P.

2013-06-01

66

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

67

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

PubMed Central

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

2013-01-01

68

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

69

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

SciTech Connect

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

Yen, H.

1992-01-01

70

The effect of transient loading on the performance of a mesophilic anaerobic contact reactor at constant feed strength.  

PubMed

Anaerobic contact reactor is a high rate anaerobic process consisting of an agitated reactor and a solids settling tank for recycling. It was proved earlier that this type of reactor design offers highly efficient performance in the conversion of organic matter to biogas. In this study, the effect of transient loading on reactor performance in terms of a number of key intermediates and parameters such as, COD removal, pH and alkalinity change, VFAs, effluent MLSS concentration and biogas efficiency over time was examined. For this purpose, a step increase of organic loading rate from 3.35kg COD/m(3)day to 15.61kg COD/m(3)day was employed. The hydraulic retention time decreased to a value of 8.42h by an increase in the influent flow-rate during the transient loading. It was observed that the mesophilic anaerobic contact reactor (MACR) was quite resistant to large transient shocks. The reactor recovered back to its baseline performance only in 15h after the shock loading was stopped. Hence, it can be concluded that this type of reactor design has a high potential in treating food processing wastewaters with varying flow characteristics. PMID:22960727

Sentürk, Elif; Ince, Mahir; Engin, Guleda Onkal

2012-12-15

71

Study on Compressed Biogas and Its Application to the Compression Ignition Dual Fuel Engine.  

National Technical Information Service (NTIS)

The paper introduces in detail the compression performance of biogas, the application of compressed biogas to the compression ignition engine and the possibility as well as the necessity of using compressed biogas. Moreover, the paper also goes further in...

C. Jiang T. Liu J. Zhong

1987-01-01

72

Performance of biogas-fed solid oxide fuel cell systems integrated with membrane module for CO 2 removal  

Microsoft Academic Search

Two SOFC systems with CO2 capture, i.e., SOFC with CO2 capture from biogas feed (biogas-cap SOFC) and SOFC with CO2 capture from reformed gas (reformed gas-cap SOFC) have been investigated. Employing the sweep gas to increase the gas separation capability, both systems offered higher power density but lower electrical efficiency than those of the SOFC without CO2 capture (non-cap SOFC).

P. Piroonlerkgul; N. Laosiripojana; A. A. Adesina; S. Assabumrungrat

2009-01-01

73

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

74

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

75

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

76

Production and Utilization of Biogas and Compost Heat.  

National Technical Information Service (NTIS)

The report deals with a plant for biogas production from manure in Rogaland (Norway). The production capacity will be about 0.6 to 1.0 m sup 3 of biogas per m sup 3 of reactor volume and day. The environmental effects have been analysed, and process param...

O. Tjernshaugen J. F. Hanssen

1984-01-01

77

Laboratory pilot scale study for H2S removal from biogas in an anoxic biotrickling filter.  

PubMed

The purpose of this laboratory pilot scale study at the Wastewater Technology Centre (WTC), Environment Canada, Burlington, ON was to investigate the anaerobic biological removal of H2S from biogas under real-time operating conditions. Biogas produced in a 538 litre pilot anaerobic digester was continuously fed into a 12 litre biotrickling filter containing plastic fibres as packing bed media. The process was monitored for several months. The biogas flowrate and H2S concentration ranged between 10 to 70 L/h and 1,000 to 4,000 ppmv respectively over the course of the test period. Nitrate-rich wastewater from a pilot scale sequencing batch reactor effluent was used as the nutritive solution for the biotrickling filter. The paper presents the influence of several operational parameters such as biogas flowrate, hydrogen sulphide concentration and composition of nutrient solution on process performance. To date, our results show H2S removal rates up to 100% without adverse effects on the methane concentration of the biogas. No system deterioration was observed over long term operation. This non-conventional technology is very promising and could be considered for full scale applications. PMID:18235172

Soreanu, G; Béland, M; Falletta, P; Edmonson, K; Seto, P

2008-01-01

78

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

79

Jules Horowitz Reactor: a high performance material testing reactor  

NASA Astrophysics Data System (ADS)

The physical modelling of materials' behaviour under severe conditions is an indispensable element for developing future fission and fusion systems: screening, design, optimisation, processing, licensing, and lifetime assessment of a new generation of structure materials and fuels, which will withstand high fast neutron flux at high in-service temperatures with the production of elements like helium and hydrogen. JANNUS and other analytical experimental tools are developed for this objective. However, a purely analytical approach is not sufficient: there is a need for flexible experiments integrating higher scales and coupled phenomena and offering high quality measurements; these experiments are performed in material testing reactors (MTR). Moreover, complementary representative experiments are usually performed in prototypes or dedicated facilities such as IFMIF for fusion. Only such a consistent set of tools operating on a wide range of scales, can provide an actual prediction capability. A program such as the development of silicon carbide composites (600-1200 °C) illustrates this multiscale strategy. Facing the long term needs of experimental irradiations and the ageing of present MTRs, it was thought necessary to implement a new generation high performance MTR in Europe for supporting existing and future nuclear reactors. The Jules Horowitz Reactor (JHR) project copes with this context. It is funded by an international consortium and will start operation in 2014. JHR will provide improved performances such as high neutron flux ( 10 n/cm/s above 0.1 MeV) in representative environments (coolant, pressure, temperature) with online monitoring of experimental parameters (including stress and strain control). Experimental devices designing, such as high dpa and small thermal gradients experiments, is now a key objective requiring a broad collaboration to put together present scientific state of art, end-users requirements and advanced instrumentation. To cite this article: D. Iracane et al., C. R. Physique 9 (2008).

Iracane, Daniel; Chaix, Pascal; Alamo, Ana

2008-04-01

80

Implementation and Utilization of Biogas.  

National Technical Information Service (NTIS)

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

J. P. Perret

1983-01-01

81

Integrated biogas systems  

NASA Astrophysics Data System (ADS)

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

Amaratunga, M.

1980-01-01

82

Whole genome sequence of Clostridium bornimense strain M2/40 isolated from a lab-scale mesophilic two-phase biogas reactor digesting maize silage and wheat straw.  

PubMed

The bacterium Clostridium bornimense M2/40 is a mesophilic, anaerobic bacterium isolated from a two-phase biogas reactor continuously fed with maize silage and 5% wheat straw. Grown on glucose, it produced H2, CO2, formiate, lactate and propionate as the main fermentation products, of which some compounds serve as substrates for methanogenic Archaea to form methane. Here, the whole genome sequence of the bacterium consisting of two circular replicons is reported. This genome information provides the basis for further studies addressing metabolic features of the isolate and its role in anaerobic biomass degradation. PMID:24905146

Hahnke, Sarah; Wibberg, Daniel; Tomazetto, Geizecler; Pühler, Alfred; Klocke, Michael; Schlüter, Andreas

2014-08-20

83

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

84

Rural Use of Biogas.  

National Technical Information Service (NTIS)

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

1976-01-01

85

Integrated biogas systems  

Microsoft Academic Search

Integrated biogas systems as alternatives to fossil fuels in Sri Lanka are considered from standpoints of population growth, land availability, and employment opportunities. Agricultural practices would be improved by use of chemical fertilizers, and health\\/nutrition problems be alleviated by using biogas systems. Fuel for cooking and rural industries will become more easily available; water weeds, such as water hyacinth and

M. Amaratunga

1980-01-01

86

Anaerobic filter for biogas production  

Microsoft Academic Search

A laboratory study evaluated the performance of an anaerobic filter in producing biogas from pig waste with 30,000 mg\\/l of COD. The filter packing was bamboo rings of 1 and 1\\/2 in. diameter, 1 in. long; the bamboo-bed filter operated satisfactorily in a wide COD loading range of 3.74-15.65 kg\\/cu m\\/d which corresponds to the hydraulic retention of 8.47 to

S. Chavadej

1980-01-01

87

Energy cogeneration with biogas fuel  

SciTech Connect

An engine-generator system, with heat recovery and thermal energy storage, was designed to operate with filtered, scrubbed biogas as a fuel. The thermal and electrical generation provided the process energy for the digester system and for an ethanol production plant. The design criteria were: performance, economy, reliability, ease of operation and safety. The system consisted of a 4 cylinder SI engine, a 20 kW induction generator, an exhaust heat recovery silencer, open loop engine heat recovery from the engine and exhaust, and stratified hot water thermal energy storage. Detailed performance data of the system components as a function of the operating parameters was collected and presented. The fuel qualities of biogas were evaluated by measuring combustion pressures and by conducting parallel experiments with commercial propane. The engine maintenance intervals were monitored, the lubricating oil was sampled and analyzed regularly, and the engine was torn down after 1700 operating hours to determine wear and reliability. Maximum power output was 20 kW at an efficiency of 26%. Thermal output was 2200 kJ/min and the overall energy yield was 75% of the fuel input energy. The engine operated well on biogas within a limited range of air-fuel mixtures and ignition timings. Engine power output was lower than for propane, but brake thermal efficiency was equal. The induction generator was interconnected with the utility grid. Generator operation and control was simple. Stratification in the thermal energy storage was nearly ideal, and a storage temperature of 99/sup 0/C could be maintained. Overall, biogas proved to be well suited as an engine fuel, and the system performed above expectations.

Stahl, T.

1983-01-01

88

Materials for high performance light water reactors  

NASA Astrophysics Data System (ADS)

A state-of-the-art study was performed to investigate the operational conditions for in-core and out-of-core materials in a high performance light water reactor (HPLWR) and to evaluate the potential of existing structural materials for application in fuel elements, core structures and out-of-core components. In the conventional parts of a HPLWR-plant the approved materials of supercritical fossil power plants (SCFPP) can be used for given temperatures (?600 °C) and pressures (?250 bar). These are either commercial ferritic/martensitic or austenitic stainless steels. Taking the conditions of existing light water reactors (LWR) into account an assessment of potential cladding materials was made, based on existing creep-rupture data, an extensive analysis of the corrosion in conventional steam power plants and available information on material behaviour under irradiation. As a major result it is shown that for an assumed maximum temperature of 650 °C not only Ni-alloys, but also austenitic stainless steels can be used as cladding materials.

Ehrlich, K.; Konys, J.; Heikinheimo, L.

2004-05-01

89

Dispersion and treatment performance analysis of an UASB reactor under different hydraulic loading rates.  

PubMed

Mixing and transport phenomena affect the efficiency of all bioreactor configurations. An even mixing pattern at the macro-level is desirable to provide good conditions for substrate transport to, and from, the microbial aggregates. The state of segregation of particulate material in the reactor is also important. The production of biogas in anaerobic reactors is another factor that affects mixing intensity and hence the interactions between the liquid, solid and gaseous phases. The CSTR model with some degree of short-circuiting, dead zones and bypassing flows seems to describe the overall hydrodynamics of UASBs. However, few data are available in the literature for full-scale reactors that relate process performance to mixing characteristics. Dispersion studies using LiCl were done for four hydraulic loading rates on a full-scale UASB treating domestic wastewater in Ginebra, Valle del Cauca, southwest Colombia. COD, TSS, and Settleable Solids were used to evaluate the performance of organic matter removal. The UASB showed a complete mixing pattern for hydraulic loading rates close to the design value (i.e. Q = 10-13l s(-1) and HRT=8-6 h). Gross mixing distortions and localised stagnant zones, short-circuiting and bypass flows were found in the sludge bed and blanket zones for both extreme conditions (underloading and overloading). The liquid volume contained below the gas-liquid-solid separator was found to contribute to the overall stagnant volume, particularly when the reactor was underloaded. The removal of organic matter showed a log-linear correlation with the dispersion number. PMID:16405944

Peña, M R; Mara, D D; Avella, G P

2006-02-01

90

MAPLE research reactor beam-tube performance.  

National Technical Information Service (NTIS)

Atomic Energy of Canada Limited (AECL) has been developing the MAPLE (Multipurpose Applied Physics Lattice Experimental) reactor concept as a medium-flux neutron source to meet contemporary research reactor applications. This paper gives a brief descripti...

A. G. Lee R. F. Lidstone G. E. Gillespie

1989-01-01

91

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

PubMed

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

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

2013-12-01

92

Co-generation of electricity and heat from biogas  

SciTech Connect

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

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

1982-12-01

93

Comparative study of biogas production from different waste materials  

Microsoft Academic Search

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

Tanusri Mandal; N. K. Mandal

1997-01-01

94

Effect of some operating parameters on biogas production rate  

Microsoft Academic Search

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

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

1995-01-01

95

[Performance and microbial characteristics of an EGSB reactor treating brewery wastewater under 20 degrees C].  

PubMed

A lab-scale EGSB reactor fed by artificial brewery wastewater was operated under 20 degrees C continuously, and its process performance, characteristics of granular sludge, microbial community structure were investigated. The results indicated that: 1) after 184 days' operation, the organic loading rate of EGSB reactor could reach 10 kg/(m3 x d) at HRT of about 18 h, the COD removal efficiencies were above 85%, and the specific biogas production was about 0.58 m3 per kilogram COD removed. 2) As the organic loading rate increased, the average diameter of the granule increased, and the settling velocity increased too, but when the loading rate reached about 10 kg/(m3 x d), the granular average diameter decreased slightly. Compared with the granular sludge operated at mesophilic condition, the ECP contents especially the protein contents in the granular sludge operated at 20 degrees C increased obviously. 3) Compared with the seed sludge, the main Archaea (methanogenes) species in the sludge samples operated at different loading rates under 20 degrees C did not change greatly, but the dominant methanogenes in the sludge operated under 15 degrees C for 6 months seeded with the same mesophilic sludge changed obviously. PMID:18637351

Li, Jin; Zuo, Jian-e; Xing, Wei

2008-04-01

96

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

97

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

98

Polyphasic Analyses of Methanogenic Archaeal Communities in Agricultural Biogas Plants?  

PubMed Central

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

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

2010-01-01

99

Biogas of manure and sludge  

NASA Astrophysics Data System (ADS)

Biogas production from farmyard manures and sewage sludges is based on anaerobic processes (methane-bacteria) and aerobic processes (fermentative bacteria). Biogas product has high calorific value and a number of small, pilot-scale and full-scale municipal systems of biogas production is described inclusive technological solutions and cost-benefit analysis. Experience of electric power generators fueled by biogas is evaluated from the view point of competitiveness with other fuels.

Kraemer, F.; Gundermann, J.; Kofoed, E.; Nielsen, J.

1981-01-01

100

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

101

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

102

Potential biogas scrubbing using a high rate pond.  

PubMed

The potential to scrub biogas in a high rate pond (HRP) was evaluated using apparatus designed to maximize gas-liquid contact. Experiments compared the removal of carbon dioxide from synthetic biogas by an "in-pond angled gutter" to that by a simulated "counter-current pit." Results showed that the counter current pit has potential for use in biogas scrubbing, with synthetic biogas carbon dioxide composition consistently reduced from 40% to < 5%. The in-pond angled gutter was less effective due to bubble coalescence which reduced the total bubble surface area available for gas transfer. Measurement of oxygen levels in the scrubbed biogas showed that despite supersaturation of oxygen in the HRP water, there was little transfer to the biogas, so that explosive methane/oxygen mixtures would not be formed. Theoretical calculations indicated that the amount of biogas likely to be formed during anaerobic treatment of municipal wastewater could be scrubbed in the HRP of the same advanced pond system with little influence on HRP pH, algal growth and treatment performance. These encouraging results justify further research on this method of biogas purification. PMID:16114691

Mandeno, G; Craggs, R; Tanner, C; Sukias, J; Webster-Brown, J

2005-01-01

103

Anaerobic treatability and biogas production potential of selected in-mill streams.  

PubMed

Biochemical methane potential assays (BMP assays) were performed to study the potential of anaerobic treatment of in-mill wastewaters. The assay results indicated that condensate and the BCTMP effluent, which are currently treated with the anaerobic internal circulation reactors, were the best streams for anaerobic treatment because of their relatively high degradability (>80%) and initial rates of biogas production. The softwood dewatering process stream was the worst with the lowest degradability (~30%). The hardwood stream was more degradable than the softwood stream from the same process. Biogas production was found to be additive and predictable in blended samples. In addition, degradability was found to be negatively correlated to the concentration of dehydroabietic acid and tannin-lignin compounds. The anaerobic treatment of the suitable streams has great potential value with significantly reduced sludge production and energy savings. PMID:21076230

Yang, M I; Edwards, E A; Allen, D G

2010-01-01

104

Reactor Coolant Pump Seals: Improving Their Performance.  

National Technical Information Service (NTIS)

Large CANDU plants are benefitting from transient-resistant four-year reliable reactor coolant pump seal lifetimes, a direct result of AECL's 20-year comprehensive seal improvement program involving R and D staff, manufacturers, and plant designers and op...

N. E. Pothier R. Metcalfe

1986-01-01

105

Start-up and operation of the first biogas station for agricultural crops in the Slovak Republic  

Microsoft Academic Search

The main objective of this work is an anaerobic treatment of maize silage and a biogas production in a full-scale reactor. Conditions of start-up and trial operation are described. The anaerobic reactor of the biogas station is seeded with aerobically stabilized sludge from wastewater treatment plant of brewery Hurbanovo. This material is not frequently used as an inoculating medium for

M. Hut?an; A. Kalina; I. Bodík; T. Petheöová

106

Liquid membrane purification of biogas  

SciTech Connect

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

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

1991-03-01

107

Biogas: Production and utilization  

Microsoft Academic Search

Among the aspects of biogas production and utilization covered are: (1) the microbiology and biochemistry of the acid and methane production stages in the anaerobic process; (2) factors affecting the process, such as temperature, acidity and alkalinity, nutrients, and cations; (3) denitrification processes and systems; and (4) the process kinetics of suspended growth systems, packed columns, and fluidized beds. Also

E. C. Price; P. N. Cheremisinoff

1981-01-01

108

Cooperative Biogas Production.  

National Technical Information Service (NTIS)

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

F. Cayrol

1983-01-01

109

Janata Biogas Plant.  

National Technical Information Service (NTIS)

The Janata biogas plant is based on the use of local materials and locally available skills only. It is a proven technology at low cost and easy maintenance which should facilitate its extension at a much faster pace especially among the low income groups...

S. Bahadur K. K. Singh

1980-01-01

110

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

111

Anaerobic digestion foaming in full-scale biogas plants: a survey on causes and solutions.  

PubMed

Anaerobic digestion foaming is a common operation problem in biogas plants with negative impacts on the biogas plants economy and environment. A survey of 16 Danish full-scale biogas plants on foaming problems revealed that most of them had experienced foaming in their processes up to three times per year. Foaming incidents often lasted from one day to three weeks, causing 20-50% biogas production loss. One foaming case at Lemvig biogas plant has been investigated and the results indicated that the combination of feedstock composition and mixing pattern of the reactor was the main cause of foaming in this case. Moreover, no difference in bacterial communities between the foaming and non-foaming reactors was observed, showing that filamentous bacteria were not the main reason for foaming in this case. PMID:24569292

Kougias, P G; Boe, K; O-Thong, S; Kristensen, L A; Angelidaki, I

2014-01-01

112

Conceptual study of test reactor for fuel irradiation/reactor performance research.  

National Technical Information Service (NTIS)

This report describes the results of conceptual design study of a test reactor for fuel irradiation research and/or reactor performance research as a central facility of the 'Integrated Test Facilities for the Future LWR Technology' which have been develo...

T. Inabe H. Nakata H. Akie

1993-01-01

113

Fast Breeder Reactor Fuel Performances: Discussion  

Microsoft Academic Search

Achieving high burn-ups of the fuel used in fast-neutron reactors is essential for the economy of the breeder system. The mixed-oxide fuel (UO2, PuO2), which is generally used, enclosed in metallic pins assembled together inside an hexagonal wrapper, suffers high irradiation damage in a very hostile environment (high temperature, severe temperature gradients, corrosive atmosphere) for long periods of time. We

R. Lallement; K. Q. Bagley

1990-01-01

114

Retrospective Search on Economics of Biogas Production.  

National Technical Information Service (NTIS)

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

1983-01-01

115

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

116

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

117

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

118

Sulfur K-edge XANES and acid volatile sulfide analyses of changes in chemical speciation of S and Fe during sequential extraction of trace metals in anoxic sludge from biogas reactors.  

PubMed

The effect of sequential extraction of trace metals on sulfur (S) speciation in anoxic sludge samples from two lab-scale biogas reactors augmented with Fe was investigated. Analyses of sulfur K-edge X-ray absorption near edge structure (S XANES) spectroscopy and acid volatile sulfide (AVS) were conducted on the residues from each step of the sequential extraction. The S speciation in sludge samples after AVS analysis was also determined by S XANES. Sulfur was mainly present as FeS (? 60% of total S) and reduced organic S (? 30% of total S), such as organic sulfide and thiol groups, in the anoxic solid phase. Sulfur XANES and AVS analyses showed that during first step of the extraction procedure (the removal of exchangeable cations), a part of the FeS fraction corresponding to 20% of total S was transformed to zero-valent S, whereas Fe was not released into the solution during this transformation. After the last extraction step (organic/sulfide fraction) a secondary Fe phase was formed. The change in chemical speciation of S and Fe occurring during sequential extraction procedure suggests indirect effects on trace metals associated to the FeS fraction that may lead to incorrect results. Furthermore, by S XANES it was verified that the AVS analysis effectively removed the FeS fraction. The present results identified critical limitations for the application of sequential extraction for trace metal speciation analysis outside the framework for which the methods were developed. PMID:22284519

Shakeri Yekta, Sepehr; Gustavsson, Jenny; Svensson, Bo H; Skyllberg, Ulf

2012-01-30

119

Anaerobic filter for biogas production  

NASA Astrophysics Data System (ADS)

A laboratory study evaluated the performance of an anaerobic filter in producing biogas from pig waste with 30,000 mg/l of COD. The filter packing was bamboo rings of 1 and 1/2 in. diameter, 1 in. long; the bamboo-bed filter operated satisfactorily in a wide COD loading range of 3.74-15.65 kg/cu m/d which corresponds to the hydraulic retention of 8.47 to 1.68 days. At the optimum loading of 7.299 kg COD/cu m/d, the largest gas rate of 0.212 cu m/kg of COD was produced. The required volume of the digester for 1.2 cu m/d of gas production would be only 1.5 cu m; in practical applications, consideration should be given to the gas collecting system and clogging problems.

Chavadej, S.

1980-01-01

120

Performance of fixed and fluidized bed reactors with immobilized enzyme  

Microsoft Academic Search

Saccharification of ?-amylase liquefied cassava starch was carried out at pH 4.5 and 45‡C, in both fixed and fluidized bed\\u000a reactors, using amyloglucosidase immobilized in 0.5 mm controlled pore silica particles. Reactor performance data are compared\\u000a with mathematical modeling. Data show that for equal normalized residence time and lower fluid-bed porosities, the fluidized\\u000a bed mode leads to higher conversions than

Gisella M. Zanin; Lauro M. Kambara; Luiza P. V. Calsavara; Flavio F. De Moraes

1994-01-01

121

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

122

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

123

The Potential of Biogas Energy  

Microsoft Academic Search

Biogas technology has been known about for a long time, but in recent years the interest in it has significantly increased, especially due to the higher costs and the rapid depletion of fossil fuels as well as their environmental considerations. The main objective of the present study is to investigate the potential of biogas energy in the 15 European Union

MUSTAFA ACAROGLU; GUNNUR KOCAR; ARIF HEPBASLI

2005-01-01

124

FARM-SCALE BIOGAS PLANTS  

Microsoft Academic Search

SUMMARY In Germany there are only about fifteen years of experiences in the planning and construction of farm- scale biogas plants. In the meantime, approximately 1,600 biogas plants are in operation under stable conditions on farms. This is primarily due to investment funding and payment for each kWh delivered to the public energy grid. In general, three different kinds of

Torsten Fischer; Krieg Kyu; Jung Chae; Seong Keun Yim; Kwang Ho Choi; Woo Kyun Park; Ki Cheol Eom

125

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 876,000m3 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

2014-04-01

126

Biogas: Production and utilization  

NASA Astrophysics Data System (ADS)

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

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

127

Janata biogas technology and fodder production  

Microsoft Academic Search

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

Neelakantan

1981-01-01

128

Analysis of tandem mirror reactor performance  

SciTech Connect

Parametric studies are performed using a tandem mirror plasma point model to evaluate the wall loading GAMMA and the physics figure of merit, Q (fusion power/injected power). We explore the relationship among several dominant parameters and determine the impact on the plasma performance of electron cyclotron resonance heating in the plug region. These global particle and energy balance studies were carried out under the constraints of magnetohydrodynamic (MHD) equilibrium and stability and constant magnetic flux, assuming a fixed end-cell geometry. We found that the higher the choke coil fields, the higher the Q, wall loading, and fusion power due to the combination of the increased central-cell field B/sub c/ and density n/sub c/ and the reduced central-cell beta ..beta../sub c/. The MHD stability requirement of constant B/sub c//sup 2/..beta../sub c/ causes the reduction in ..beta../sub c/. In addition, a higher value of fusion power can also be obtained, at a fixed central-cell length, by operating at a lower value of B/sub c/ and a higher value of ..beta../sub c/.

Wu, K.F.; Campbell, R.B.; Peng, Y.K.M.

1984-11-01

129

The Performance of Structured Packings in Trickle-Bed Reactors  

Microsoft Academic Search

An experimental study was carried out to investigate whether the use of structured packings might improve the mass transfer characteristics and the catalyst effectiveness of a trickle-bed reactor. Therefore, the performances of a structured packing, consisting of KATAPAK elements, and a dumped packing, consisting of small diameter spherical particles, have been compared for both a chemisorption process and a process

M. J. W. Frank; J. A. M. Kuipers; G. F. Versteeg; W. P. M. Van swaaij

1999-01-01

130

Density dependence of reactor performance with thermal confinement scalings  

SciTech Connect

Energy confinement scalings for the thermal component of the plasma published thus far have a different dependence on plasma density and input power than do scalings for the total plasma energy. With such thermal scalings, reactor performance (measured by Q, the ratio of the fusion power to the sum of the ohmic and auxiliary input powers) worsens with increasing density. This dependence is the opposite of that found using scalings based on the total plasma energy, indicating that reactor operation concepts may need to be altered if this density dependence is confirmed in future research.

Stotler, D.P.

1992-03-01

131

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

Microsoft Academic Search

This study characterizes the rate processes of substrate utilization, biogas production, and biomass accumulation in methanogenic fluidized bed reactors (FBRs), which use Manville R-633 beads as the growth support media, acetate enriched bacterial culture as the inoculum, and acetic acid as the sole substrate, during start-up and steady-state phases. Two start-up strategies, one based on maximum substrate utilization and the

Yen

1992-01-01

132

Development of a Biogas Plant  

Microsoft Academic Search

To meet the rural domestic energy needs, a design for 1–2 m Himshakti biogas plant is developed and evaluated. This design is also suitable for the topography with soils of stony strata and can be partly installed with locally available stones. 1 m and 2 m biogas plants cost Rs. 6491 ($138.1) and Rs. 9984 ($214.4), respectively. If the stones

ANJAN KALIA; SHIV SINGH

2004-01-01

133

Computational Neutronics Methods and Transmutation Performance Analyses for Fast Reactors  

SciTech Connect

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

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

2007-03-01

134

Economic analysis of anaerobic digestion—A case of Green power biogas plant in The Netherlands  

Microsoft Academic Search

One of the key concerns of biogas plants is the disposal of comparatively large amounts of digestates in an economically and environmentally sustainable manner. This paper analyses the economic performance of anaerobic digestion of a given biogas plant based on net present value (NPV) and internal rate of return (IRR) concepts. A scenario analysis is carried out based on a

Solomie A. Gebrezgabher; Miranda P. M. Meuwissen; Bram A. M. Prins

2010-01-01

135

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

Microsoft Academic Search

A laboratory-scale (40l) 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 (21m3) with the same feedstock. Biogas and methane production at

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

2010-01-01

136

Economic viability of biogas technology  

SciTech Connect

Biogas has emerged as a suitable technology for providing alternative and additional sources of energy, especially for rural areas of developing countries. Although the experience gained in China and India established its technological success, social scientists are still involved in the controversial issue of its economic viability. The available literature presents very contradictory situations, ranging between the two extreme poles of high economic viability and nonviability. Such contradictory conclusions are derived since economic benefits from the technology are influenced by a number of factors. A review of the literature reveals that various factors are either not considered, or that the economics have been worked out assuming a very ideal situation, while biogas plants are operating under very different conditions. Using the coal replacement method even as coal is seldom used by villages is only a single example of this approach. In most of the developing countries, rural populations depend mainly on non-commercial fuels like firewood, dungcakes, agricultural wastes and leaves for cooking and heating purposes. Under the present technological limitations, biogas can most commonly be used for cooking and lighting. For testing the economic viability of biogas systems, a number of authors have considered the benefits in terms of savings in traditional fuels. But considering the actual thermal efficiency of different non-commercial fuel items, as well as biogas, it has still be be decided at what point of the market prices of fuel items that the biogas system becomes economically viable and remains viable. The present paper thus reviews different approaches adopted and suggested for working out the economics or the cost-benefit ratio of the biogas technology at the first stage, and then spells out the factors influencing the economic benefits of the technology under various situations, with the help of empirical

Agrawal, S.C.; Agrawal, S.; Khare, O.P.

1983-12-01

137

Materials performance in nuclear pressurized water reactor steam generators  

SciTech Connect

The nuclear industry has had a variety of reliability problems with pressurized water reactor steam generators. Most of these problems have been associated with corrosion and mechanically induced damage, including secondary water intergranular corrosion and stress corrosion cracking (SCC), primary water SCC, wastage, high cycle fatigue, and fretting and wear of the Inconel 600 or Incoloy 800 tubes, plus accelerated corrosion of carbon steel tube support structures in crevice regions. This article discusses steam generator material performance. 23 refs.

Green, S.J.; Paine, J.P.N.

1981-10-01

138

Studies in biogas technology. Part III. Thermal analysis of biogas plants  

Microsoft Academic Search

A thermal model for a conventional biogas plant has been developed in order to understand the heat transfer from the slurry\\u000a and the gas holder to the surrounding earth and air respectively. The computations have been performed for two conditions\\u000a : (i) when the slurry is at an ambient temperature of 20°C, and (ii) when it is at 35°C, the

C. R. Prasad; S. R. C. Sathyanarayan

1979-01-01

139

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

140

Compressed Biogas at the Christchurch Drainage Board.  

National Technical Information Service (NTIS)

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

1986-01-01

141

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

142

Economic Aspects of Biogas Production in Agriculture.  

National Technical Information Service (NTIS)

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

G. Frick

1983-01-01

143

Feasibility of Biogas Production on Farms.  

National Technical Information Service (NTIS)

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

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

1982-01-01

144

Collection, Analysis, and Utilization of Biogas from Anaerobic Treatment of Crab Processing Waters  

Microsoft Academic Search

Two laboratory-scale, upflow anaerobic reactors were constructed to treat blue crab (Callinectes sapidus) cooking wastewater for determination of the volume and composition of the resulting bio-gas. Both systems (A and B) consisted of two 4-liter (L) upflow anaerobic reactors and one 8-L aerobic reactor in series. The first anaerobic reactor of System A contained 240,12.7 mm foam cubes, while the

J. S. Rodenhizer; G. D. Boardman

1999-01-01

145

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

146

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

147

Janata Biogas Technology and Fodder Production.  

National Technical Information Service (NTIS)

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 th...

S. Neelakantan

1981-01-01

148

Biogas in China 1981 - a Travel Report.  

National Technical Information Service (NTIS)

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

B. Frostell J. Norrman

1982-01-01

149

The feasibility of biogas production on farms  

Microsoft Academic Search

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

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

1982-01-01

150

Relation between Fodder and Biogas Yield.  

National Technical Information Service (NTIS)

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

N. Oestergaard

1985-01-01

151

Biogas production from Jatropha curcas press-cake  

SciTech Connect

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

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

1997-12-31

152

Biogas production from Jatropha curcas press-cake.  

PubMed

Seeds of the tropical plant Jatropha curcas (purge nut, physic nut) are used for the production of oil. Several methods for oil extraction have been developed. In all processes, about 50% of the weight of the seeds remain as a press cake containing mainly protein and carbohydrates. Investigations have shown that this residue contains toxic compounds and cannot be used as animal feed without further processing. Preliminary experiments have shown that the residue is a good substrate for biogas production. Biogas formation was studied using a semicontinous upflow anaerobic sludge blanket (UASB) reactor; a contact-process and an anaerobic filter each reactor having a total volume of 110 L. A maximum production rate of 3.5 m3 m"3 d"1 was obtained in the anaerobic filter with a loading rate of 13 kg COD m~3 d"1. However, the UASB reactor and the contact-process were not suitable for using this substrate. When using an anaerobic filter with Jatropha curcas seed cake as a substrate, 76% of the COD was degraded and 1 kg degraded COD yielded 355 L of biogas containing 70% methane. PMID:18576103

Staubmann, R; Foidl, G; Foidl, N; Gübitz, G M; Lafferty, R M; Arbizu, V M; Steiner, W

1997-01-01

153

Evaluation of performance of select fusion experiments and projected reactors  

NASA Technical Reports Server (NTRS)

The performance of NASA Lewis fusion experiments (SUMMA and Bumpy Torus) is compared with other experiments and that necessary for a power reactor. Key parameters cited are gain (fusion power/input power) and the time average fusion power, both of which may be more significant for real fusion reactors than the commonly used Lawson parameter. The NASA devices are over 10 orders of magnitude below the required powerplant values in both gain and time average power. The best experiments elsewhere are also as much as 4 to 5 orders of magnitude low. However, the NASA experiments compare favorably with other alternate approaches that have received less funding than the mainline experiments. The steady-state character and efficiency of plasma heating are strong advantages of the NASA approach. The problem, though, is to move ahead to experiments of sufficient size to advance in gain and average power parameters.

Miley, G. H.

1978-01-01

154

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

155

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

156

Effects of sawdust on biogas production from cowdung  

SciTech Connect

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

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

1991-01-01

157

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

158

Biogenic Hydrogen Conversion of De-Oiled Jatropha Waste via Anaerobic Sequencing Batch Reactor Operation: Process Performance, Microbial Insights, and CO2 Reduction Efficiency  

PubMed Central

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 celluloytic and fermentative bacteria were present in the hydrogen producing ASBR.

Lin, Chiu-Yue

2014-01-01

159

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

160

The Utilization of Non-edible Oil Cake Along With Cow Dung for Methane-enriched Biogas Production Using Mixed Inoculum  

Microsoft Academic Search

Different proportions (i.e., 25, 50 and 75%) of each of the non-edible oil cakes such as jatropha, karanja and safflower along with cow dung was studied for biogas production in a 1 L batch reactor using mixed inoculum IRP (a combination of inoculum from a biogas plant, municipal waste digester and rice paddy soil adopted on cow dung). The range

R. Singh; S. K. Mandal

2011-01-01

161

Assessment of Beam Tube Performance for the Maple Research Reactor.  

National Technical Information Service (NTIS)

The MAPLE research reactor is a versatile new research facility that can be adapted to meet the requirements of a variety of reactor applications. A particular group of reactor applications involves the use of beams of radiation extracted from the reactor...

A. G. Lee

1986-01-01

162

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

163

Smaa biogasanlaeg. (Small biogas plant).  

National Technical Information Service (NTIS)

The design of the described biogas plant was developed from a prototype system used on individual farms in order that it could be integrated in a communal system where biomass is driven in from other farms in addition to organic wastes. Energy from such a...

L. Baadstorp E. Hannibal

1991-01-01

164

Anaerobic digestion of different feedstocks: impact on energetic and environmental balances of biogas process.  

PubMed

The possibility of limiting the global warming is strictly linked to the reduction of GHG emissions. Renewable energy both allows reducing emissions and permits to delay fossil fuel depletion. The anaerobic digestion of animal manure and energy crops is a promising way of reducing GHG emissions. In Italy agricultural biogas production was considerably increased; nowadays there are about 520 agricultural biogas plants. The increasing number of biogas plants, especially of those larger than 500 kW(e) (electrical power), involves a high consumption of energy crops, large transport distances of biomass and digestate and difficulties on thermal energy valorization. In this study the energetic (CED) and environmental (GHG emissions) profiles associated with the production of electricity derived from biogas have been identified. Three biogas plants located in Northern Italy have been analyzed. The study has been carried out considering a cradle-to-grave perspective and thus, special attention has been paid on the feedstock production and biogas production process. The influences on the results taking into account different plant sizes and feeding rate has been assessed in detail. Energy analysis was performed using the Cumulative Energy Demand method (CED). The climate change was calculated for a 100-year time frame based on GHG emissions indicated as CO2 equivalents (eq) and defined by the IPCC (2006). In comparison to the fossil reference system, the electricity production using biogas saves GHG emissions from 0.188 to 1.193 kg CO2eq per kWh(e). Electricity supply from biogas can also contribute to a considerable reduction of the use of fossil energy carriers (from -3.97 to 10.08 MJ(fossil) per kWh(e)). The electricity production from biogas has a big potential for energy savings and reduction of GHG emissions. Efficient utilization of the cogenerated heat can substantially improve the GHG balance of electricity production from biogas. PMID:23831800

Bacenetti, Jacopo; Negri, Marco; Fiala, Marco; González-García, Sara

2013-10-01

165

Blanket materials for fusion reactors: Comparisons of thermochemical performance  

NASA Astrophysics Data System (ADS)

Thermodynamic calculations were made to predict the thermochemical performance of the fusion reactor breeder materials, Li2O, LiAlO2, and Li4SiO4 in the temperature range 900 to 1200 K and in the oxygen activity range 10(-25) to 10(-5). Except for a portion of these ranges, the performance of LiAlO2 is predicted to be better than that of Li2O and Li4SiO4. The protium purge technique for enhancing tritium release is explored for the Li2O system; it appears advantageous at higher temperatures but should be used cautiously at lower temperatures. Oxygen activity is an important variable in these systems and must be considered in executing and interpreting measurements on rates of tritium release, the form of released tritium, diffusion of tritiated species and their identities, retention of tritium in the condensed phase, and solubility of hydrogen isotope gases.

Johnson, C. E.; Fischer, A. K.; Tetenbaum, M.

166

Novel Application of Vermiculite for Siloxane Removal from Biogas  

Microsoft Academic Search

The application of biogas in powering microturbines, gas turbines, and fuel cells calls for low levels of siloxanes in biogas. At present, the generated biogas is filtered with activated carbon filter to remove siloxane prior to power generation application. This paper will report the novel application of vermiculite for siloxane removal from biogas. In adsorption studies conducted with untreated biogas

Nadim Khandaker; Peter Seto

2010-01-01

167

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

Microsoft Academic Search

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

P. M. Magee; A. Hunsbedt

1989-01-01

168

Graphite first wall thermal performance in ICF reactor  

NASA Astrophysics Data System (ADS)

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

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

1986-11-01

169

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

170

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

2014-05-01

171

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

PubMed Central

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

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

2010-01-01

172

Family and Community Biogas Plants in Rural India and China.  

National Technical Information Service (NTIS)

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

R. Roy

1980-01-01

173

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

174

Problems with biogas plants in himachal pradesh  

Microsoft Academic Search

Himachal Pradesh is a hilly state and, due to the undulating topography and wide variation in climatic conditions, there is a restriction in propagation of all the approved biogas plants for the whole of the state. Of the approved models, fixed-dome-type biogas plants, Janta and Deenbandhu, have been propagated since 1982. In recent years, KVIC has been installing drum-type biogas

Shiv P. Singh; D. K. Vatsa; H. N. Verma

1997-01-01

175

Generation of biogas from Salvinia molesta (Mitchell) on a commercial biogas digester  

Microsoft Academic Search

The paper describes the first?ever successful experiments for utilising the water polluting aquatic weed Salvinia molesta for generation of biogas on a commercial digester. The experiments were carried out on a 3 cum capacity, semi continuous type, commercialised biogas digester of KVIC (Khadi and Village Industries Commission, India) design. The digester was primarily designed and marketed for biogas production from

S. A. Abbasi; P. C. Nipaney

1984-01-01

176

Stable isotope composition of biogas allows early warning of complete process failure as a result of ammonia inhibition in anaerobic digesters.  

PubMed

Four 15-L lab-scale continuous stirred tank reactors were operated under mesophilic conditions to investigate the effect of ammonia inhibition. Stable isotope fingerprinting of biogas was applied as a process monitoring tool. Ammonia inhibition was initiated by amendment of chicken manure to maize silage fed reactors. During the accumulation of ammonia, the concentration of volatile fatty acids increased while the biogas production and pH decreased. However, in one reactor, an inhibited steady state with stable gas production even at high ammonia levels was achieved, while the other reactor proceeded to complete process failure. A depletion of the ?(13)CH4 and ?(13)CO2 values preceded the process inhibition. Moreover, the stable isotope composition of biogas also forecasted the complete process failure earlier than other standard parameters. The stable isotope analyses of biogas have a potential for mechanistic insights in anaerobic processes, and may be used to pre-warn process failure under stress conditions. PMID:24994682

Lv, Zuopeng; Hu, Meng; Harms, Hauke; Richnow, Hans Hermann; Liebetrau, Jan; Nikolausz, Marcell

2014-09-01

177

Biotechnological intensification of biogas production  

Microsoft Academic Search

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

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

2007-01-01

178

Design and analysis of a thermal core for a high performance light water reactor  

Microsoft Academic Search

The High Performance Light Water Reactor is a Generation IV light water reactor concept, operated at a supercritical pressure of 25MPa with a core outlet temperature of 500°C. A thermal core design for this reactor has been worked out by a consortium of Euratom member states within the 6th European Framework Program. Aiming at peak cladding temperatures of less than

T. Schulenberg; C. Maráczy; J. Heinecke; W. Bernnat

2011-01-01

179

A Computer Program Predicting Steady-State Performance of a Nuclear Research Reactor's Cooling System  

Microsoft Academic Search

The performances of a nuclear reactor are directly affected by its cooling system, especially when it uses wet towers to evacuate the heat generated in the nuclear reactor core. Failure of the cooling system can yield very serious damages to most of the components of the nuclear reactor core. In this work, a computer program simulating the thermal behavior of

Sidi Ali; Kamel

2002-01-01

180

Effects of organic, hydraulic and fat shocks on the performance of UASB reactors with intermittent operation  

Microsoft Academic Search

Three lab-scale UASB reactors operated at 35°C in an intermittent mode were subject to different step shocks: hydraulic, organic and feed fat content. The results show that the reactors have good resistance to the applied shocks and suggest that a feedless period is beneficial to the performance of the reactors, due to stabilisation of accumulated organic matter. Keywords COD conversion;

H. Nadais; I. Capela; L. Arroja; A. Duarte

2001-01-01

181

Steam Generator Tube Performance: Experience with Water-Cooled Nuclear Power Reactors During 1983 and 1984.  

National Technical Information Service (NTIS)

A review of the performance of steam generator tubes in water-cooled nuclear power reactors showed that tubes were plugged at 47 (35.6%) of the reactors in 1983 and at 63 (42.6%) of the reactors during 1984. In 1983 and 1984 3291 and 3335 tubes, respectiv...

O. S. Tatone P. Meindl G. F. Taylor

1986-01-01

182

Steam Generator Tube Performance. Experience with Water-Cooled Nuclear Power Reactors During 1980.  

National Technical Information Service (NTIS)

The performance of steam generator tubes in water-cooled nuclear power reactors has been reviewed for 1980. Tube defects occurred at 38% of the 97 reactors surveyed. This is a marginal improvement over 1979 when defects occurred at 41% of the reactors. Th...

O. S. Tatone R. S. Pathania

1982-01-01

183

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

184

Blanket materials for fusion reactors: comparisons of thermochemical performance  

SciTech Connect

Thermodynamic calculations have been made to predict the thermochemical performance of the fusion reactor breeder materials, Li/sub 2/O, LiAlO/sub 2/, and Li/sub 4/SiO/sub 4/ in the temperature range 900 to 1300/sup 0/K and in the oxygen activity range 10/sup -25/ to 10/sup -5/. Except for a portion of these ranges, the performance of LiAlO/sub 2/ is predicted to be better than that of Li/sub 2/O and Li/sub 4/SiO/sub 4/. The protium purge technique for enhancing tritium release is explored for the Li/sub 2/O system; it appears advantageous at higher temperatures but should be used cautiously at lower temperatures. Oxygen activity is an important variable in these systems and must be considered in executing and interpreting measurements on rates of tritium release, the form of released tritium, diffusion of tritiated species and their identities, retention of tritium in the condensed phase, and solubility of hydrogen isotope gases.

Johnson, C.E.; Fischer, A.K.; Tetenbaum, M.

1984-01-01

185

Prism sodium-cooled reactor design and performance  

Microsoft Academic Search

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

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

1989-01-01

186

Determination of heat losses in biogas installations  

Microsoft Academic Search

During the winter 1979\\/80 a biogas plant located on an average sized dairy farm was monitored with respect to its heat requirements. The results showed that the energy consumption was higher than the energy content of the biogas produced. A comparison of the data collected with the calculated heat losses indicated strongly that substantial amounts of heat were lost through

R. Fischer; A. Wellinger

1981-01-01

187

Essential technical parameters for effective biogas production  

Microsoft Academic Search

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

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

188

Socioeconomic Analysis of Centralised Biogas Plants  

Microsoft Academic Search

The development of biogas technology in Denmark has been widely encouraged by the government over the last 15 years. The overall reasons for the government concern has been the increasing awareness that centralised biogas plants make a significant contribution to solve a range of problems in the fields of energy, agriculture and environment. This has been documented through related monitoring

L. H. Nielsen; K. Hjort-Gregersen

189

Energetics of household biogas plants in India  

Microsoft Academic Search

An attempt to assess the energetic feasibility of family size biogas plants has been made. The standard technique of process analysis has been used to determine the energy yield ratio of the three popular designs of biogas plants in India. The effects of size and retention time on energy yield ratio have also been studied.

S. Rubab; T. C. Kandpal

1995-01-01

190

Immobilized cell reactor with simultaneous product separation. II. Experimental reactor performance  

Microsoft Academic Search

The Immobilized Cell Reactor-Separator (ICRS) consists of two column reactors: a cocurrent gas-liquid enricher followed by a countercurrent stripper. The columns are four-phase tubular reactors consisting of 1) an inert gas phase, 2) the liquid fermentation broth, 3) the solid column internal packing, and 4) the immobilized biological catalyst or cells. The application of the ICRS to the ethanol-from-whey-lactose fermentation

M. C. Dale; M. R. Okos; P. C. Wankat

1985-01-01

191

Autotrophic denitrification for combined hydrogen sulfide removal from biogas and post-denitrification.  

PubMed

In this paper we describe an alternative flow-chart for full treatment of wastewaters rich in organic substrates, ammonia (or organic nitrogen), and sulfate, such as those generated in fish cannery industries. Biogas generated during anaerobic pretreatment of these wastewaters is rich in hydrogen sulfide that needs to be removed to enable application of the biogas. Nitrogen elimination is traditionally achieved by subsequent nitrification and denitrification of the effluent of the anaerobic reactor. Alternatively, the hydrogen sulfide in the biogas can be applied as an electron donor in an autotrophic post-denitrification step. In order to study whether sufficient hydrogen sulfide containing biogas for denitrification was produced in the anaerobic reactor, the biogas composition as a function of the anaerobic reactor-pH was estimated based on a typical wastewater composition and chemical equilibrium equations. It is demonstrated that typical sulfate and nitrogen concentrations in fish cannery wastewater are highly appropriate for application of autotrophic post-denitrification. A literature review furthermore suggested that the kinetic parameters for autotrophic denitrification by Thiobacillus denitrificans represent no bottleneck for its application. Initial experimental studies in fixed-film reactors were conducted with sodium sulfide and nitrate as an electron donor-acceptor couple. The results revealed that only moderate volumetric treatment capacities (< 1 g-NO3- N l(-1) day(-1)) could be achieved. Mass balances suggested that incomplete sulfide oxidation to elemental sulfur occurred, limiting biomass retention and the treatment capacity of the reactor. Future research should clarify the questions concerning product formation from sulfide oxidation. PMID:12188569

Kleerebezem, R; Mendez, R

2002-01-01

192

Purification of high strength wastewater originating from bioethanol production with simultaneous biogas production  

Microsoft Academic Search

In this study, purification of the wastewater from corn stover-based bioethanol production process with simultaneous biogas\\u000a production was investigated in a combined system, which was based on thermophilic anaerobic digestion in a fluidized bed reactor\\u000a (AFBR), an aerobic airlift loop reactor (ALR), and a biological aerated filter (BAF). High strength distillery wastewater\\u000a and high ammonia nitrogen content pretreatment wastewater were

Chunsheng Qiu; Xiaoqiang Jia; Jianping Wen

193

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

194

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

195

Planning Support Document for the EPRI Light Water Reactor Fuel Performance Program.  

National Technical Information Service (NTIS)

The report describes the various projects comprising the EPRI Light Water Reactor (LWR) Fuel Performance Program. The overall goal of this program is to develop a comprehensive fuel performance data base with verified predictive models and codes that can ...

J. T. A. Roberts F. E. Gelhaus H. Ocken S. T. Oldberg G. R. Thomas

1977-01-01

196

Thermal energy from a biogas engine/generator system  

SciTech Connect

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

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

1982-12-01

197

Life cycle assessment of biogas upgrading technologies.  

PubMed

This article evaluates the life cycle assessment (LCA) of three biogas upgrading technologies. An in-depth study and evaluation was conducted on high pressure water scrubbing (HPWS), as well as alkaline with regeneration (AwR) and bottom ash upgrading (BABIU), which additionally offer carbon storage. AwR and BABIU are two novel technologies that utilize waste from municipal solid waste incinerators - namely bottom ash (BA) and air pollution control residues (APC) - and are able to store CO(2) from biogas through accelerated carbonation processes. These are compared to high pressure water scrubbing (HPWS) which is a widely used technology in Europe. The AwR uses an alkaline solution to remove the CO(2) and then the solution - rich in carbonate and bicarbonate ions - is regenerated through carbonation of APC. The BABIU process directly exposes the gas to the BA to remove and immediately store the CO(2), again by carbonation. It was determined that the AwR process had an 84% higher impact in all LCA categories largely due to the energy intensive production of the alkaline reactants. The BABIU process had the lowest impact in most categories even when compared to five other CO(2) capture technologies on the market. AwR and BABIU have a particularly low impact in the global warming potential category as a result of the immediate storage of the CO(2). For AwR, it was determined that using NaOH instead of KOH improves its environmental performance by 34%. For the BABIU process the use of renewable energies would improve its impact since accounts for 55% of the impact. PMID:22230660

Starr, Katherine; Gabarrell, Xavier; Villalba, Gara; Talens, Laura; Lombardi, Lidia

2012-05-01

198

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

199

Fuel processing of biogas for small fuel cell power plants  

NASA Astrophysics Data System (ADS)

Biogas has a huge potential as fuel for fuel cell power plants. In the present work developments in fuel processing of biogas for a phosphoric acid fuel cell power plant to be located in rural India are described. Experimental work including steam reforming and shift conversion of biogas and methane has been carried out in a laboratory development unit. It is confirmed that biogas is not only a useful fuel but also that the carbon dioxide in biogas has a positive effect on methane conversion. The biogas fuel cell power plant will give a high electrical efficiency on the small scale of biogas units.

Thyberg Naumann, Sara; Myrén, Carin

200

Biogas, compost and fuel cells  

SciTech Connect

A pilot project now under development in Folsom, California, incorporates an anaerobic digestion/aerobic composting process that could eventually supply enough biogas to a fuel cell. The Sacramento Municipal Utility District (SMUD) has two fuel cells in operation and is participating in the research project. Recently, the California Prison Industry Authority (PIA) began operating a processing facility at the Folsom prison, designed for 100 tons/day of mixed waste from the City of Folsom. The 35,000 square foot Correctional Resource Recovery Facility (CRRF) uses minimum security inmates from Folsom`s Return to Custody Facility to manually separate recyclables and compostable materials from the waste stream. The PIA will be using a new technology, high solids anaerobic digestion, to compost the organic fraction (representing approximately 60 to 70 percent of the waste stream). Construction began in June on a 40-foot wide by 120-foot long and 22-foot deep anaerobic digester. Once the vessel is operational in 1995, the composting process and the gradual breakdown of organic material will produce biogas, which SMUD hopes to use to power an adjacent two megawatt fuel cell. The electricity generated will serve SMUD customers, including the waste facility and nearby correctional institutions. 1 fig.

Wichert, B.; Wittrup, L.; Robel, R. [Sacramento Municipal Utility District, CA (United States)

1994-08-01

201

Benefits of supplementing an industrial waste anaerobic digester with energy crops for increased biogas production.  

PubMed

Currently, there is increasing competition for waste as feedstock for the growing number of biogas plants. This has led to fluctuation in feedstock supply and biogas plants being operated below maximum capacity. The feasibility of supplementing a protein/lipid-rich industrial waste (pig manure, slaughterhouse waste, food processing and poultry waste) mesophilic anaerobic digester with carbohydrate-rich energy crops (hemp, maize and triticale) was therefore studied in laboratory scale batch and continuous stirred tank reactors (CSTR) with a view to scale-up to a commercial biogas process. Co-digesting industrial waste and crops led to significant improvement in methane yield per ton of feedstock and carbon-to-nitrogen ratio as compared to digestion of the industrial waste alone. Biogas production from crops in combination with industrial waste also avoids the need for micronutrients normally required in crop digestion. The batch co-digestion methane yields were used to predict co-digestion methane yield in full scale operation. This was done based on the ratio of methane yields observed for laboratory batch and CSTR experiments compared to full scale CSTR digestion of industrial waste. The economy of crop-based biogas production is limited under Swedish conditions; therefore, adding crops to existing industrial waste digestion could be a viable alternative to ensure a constant/reliable supply of feedstock to the anaerobic digester. PMID:21975301

Nges, Ivo Achu; Escobar, Federico; Fu, Xinmei; Björnsson, Lovisa

2012-01-01

202

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

203

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

204

Prism sodium-cooled reactor design and performance  

SciTech Connect

The Power Reactor Inherently Safe Module (PRISM) program is being conducted at General Electric (GE) under U.S. Department of Energy sponsorship to develop a conceptual design for an advanced sodium-cooled liquid-metal reactor plant. The PRISM design emphasizes inherent safety, modular construction, and factory fabrication. A PRISM power plant includes a number of reactor modules, which will be fabricated in a factory and shipped by whatever combination of barge, rail, and road transport that is most economical for a particular site. The target commercial PRISM plant utilizes nine reactor modules arranged in three identical 465-MW(electric) power blocks for an overall plant net electrical rating of 1395 MW(electric). Each power block has three identical reactor modules, each with its own steam generator, that jointly supply saturated steam to a single turbine generator. The PRISM's features of fewer and simpler safety systems, seismic isolation, passive decay heat removal, inherent reactivity control, and generous margins from structural and fuel damage limits during potential accident situations will result in significant gains in public safety and protection of the owner's investment. The use of standardized modular construction and extensive factory fabrication is resulting in a plant design that is economically competitive against projected coal plants and other nuclear design approaches.

Kwant, W.; Magee, P.M.; Patel, M.R. (GE, San Jose, CA (USA))

1989-01-01

205

Investigation of factors influencing biogas production in a large-scale thermophilic municipal biogas plant  

Microsoft Academic Search

A continuously operated, thermophilic, municipal biogas plant was observed over 26 months (sampling twice per month) in regard\\u000a to a number of physicochemical parameters and the biogas production. Biogas yields were put in correlation to parameters such\\u000a as the volatile fatty acid concentration, the pH and the ammonium concentration. When the residing microbiota was classified\\u000a via analysis of the 16S rRNA

Agnes Weiss; Valérie Jérôme; Diana Burghardt; Likke Likke; Stefan Peiffer; Eugen M. Hofstetter; Ralf Gabler; Ruth Freitag

2009-01-01

206

Steam-generator tube performance: world experience with water-cooled nuclear power reactors during 1977  

Microsoft Academic Search

The performance of steam-generator tubes in water-cooled nuclear power reactors in various countries is reviewed for 1977. Tube failures were reported at 34 of the 79 reactors surveyed. The causes of these failures and the inspection and repair procedures designed to deal with them are presented. Although denting caused by corrosion remained the leading cause of tube failures, specific mechanisms

R. S. Pathania; O. S. Tatone

1979-01-01

207

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

Microsoft Academic Search

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

Kai Fischer; Eckart Laurien; Andreas G. Claas; Thomas Schulenberg

2007-01-01

208

Steam Generator Tube Performance: Experience with Water-Cooled Nuclear Power Reactors During 1978.  

National Technical Information Service (NTIS)

The performance of steam generator tubes in water-cooled nuclear power reactors has been reviewed for 1978. Tube failures occurred at 31 of the 86 reactors surveyed. Causes of these failures and procedures designed to deal with them are described. A drama...

O. S. Tatone R. S. Pathania

1980-01-01

209

Steam Generator Tube Performance: Experience with Water-Cooled Nuclear Power Reactors During 1977.  

National Technical Information Service (NTIS)

The performance of steam generator tubes in water-cooled nuclear power reactors has been reviewed for 1977. Failures were reported in 34 of the 79 reactors surveyed. Causes of these failures and inspection and repair procedures designed to deal with them ...

R. S. Pathania O. S. Tatone

1979-01-01

210

Steam Generator Tube Performance. Experience with Water-Cooled Nuclear Power Reactors During 1982.  

National Technical Information Service (NTIS)

A review of the performance of steam generator tubes in 116 water-cooled nuclear power reactors showed that tubes were plugged at 54 (46 percent) of the reactors. The number of tubes removed from service decreased from 4,692 (0.30 percent) in 1981 to 3,22...

O. S. Tatone R. S. Pathania

1984-01-01

211

Steam Generator Tube Performance: Experience with Water-Cooled Nuclear Power Reactors During 1979.  

National Technical Information Service (NTIS)

The performance of steam generator tubes in water-cooled nuclear power reactors has been reviewed for 1979. Tube failures occurred at 38 of the 93 reactors surveyed. Causes of these failures and procedures designed to deal with them are described. The def...

O. S. Tatone R. S. Pathania

1981-01-01

212

Steam Generator Tube Performance. Experience with Water-Cooled Nuclear Power Reactors During 1981.  

National Technical Information Service (NTIS)

A review of the performance of steam generator tubes in 110 water-cooled nuclear power reactors showed that tubes were plugged at 46 (42 percent) of the reactors. The number of tubes removed from service increased from 1900 (0.14 percent) in 1980 to 4692 ...

O. S. Tatone R. S. Pathania

1983-01-01

213

Steam generator tube performance. Experience with water-cooled nuclear power reactors during 1985.  

National Technical Information Service (NTIS)

The performance of steam generator tubes at water-cooled reactors during 1985 has been reviewed. Seventy-three of 168 reactors in the survey experienced tube degradation sufficient for the tubes to be plugged. The number of tubes plugged was 6837 or 0.28%...

O. S. Tatone R. L. Tapping

1988-01-01

214

Performance of the Cascade Inertial-Confinement-Fusion Conceptual Reactor.  

National Technical Information Service (NTIS)

A 4.5-m-radius rotating fusion reactor made of silicon carbide and containing a moving 1-m-thick lithium-ceramic granular blanket can produce 3000 MW/sub t/. The blanket operates at high temperature (>1200 K) leading to gross plant efficiencies of up to 6...

J. H. Pitts

1984-01-01

215

Materials performance in nuclear pressurized water reactor steam generators  

Microsoft Academic Search

The nuclear industry has had a variety of reliability problems with pressurized water reactor steam generators. Most of these problems have been associated with corrosion and mechanically induced damage, including secondary water intergranular corrosion and stress corrosion cracking (SCC), primary water SCC, wastage, high cycle fatigue, and fretting and wear of the Inconel 600 or Incoloy 800 tubes, plus accelerated

S. J. Green; J. P. N. Paine

1981-01-01

216

Performance of Liquid Metals in Natural Circulation Cooled Nuclear Reactors  

Microsoft Academic Search

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

Carlos Ceballos; Danny Lathouwers; Adrian Verkooijen

2004-01-01

217

Effects of fines and velocity on fluid bed reactor performance  

Microsoft Academic Search

In a pilot plant reactor it is shown that increasing fines content of the catalyst charge increases the conversion per unit residence time of gas. Similarly, increasing the velocity also increases the conversion. The results are explained using a model of combined diffusional and reaction resistance in the fluid bed.

M. Pell; S. P. Jordan

1987-01-01

218

Introduction to Biogas Production on the Farm.  

National Technical Information Service (NTIS)

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

1984-01-01

219

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

220

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

221

Cogeneration of electricity and heat from biogas  

SciTech Connect

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

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

1986-03-01

222

Integration of Biogas Plants in Farm Economy.  

National Technical Information Service (NTIS)

This study deals with the optimising of dimensions and most practical designing of biogas plants not yet planned, and the organisational integration of such plants into individual agricultural businesses. The essay is addressed mainly to building experts,...

R. Kaufmann

1984-01-01

223

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

224

Concept for slurry separation and biogas production  

US Patent & Trademark Office Database

The present invention concerns an anaerobic digestion of animal manures, energy crops and similar organic substrates. The process is capable of refining nutrients comprised in the digested biomass to fertilizers of commercial quality. The invention also provides a method for oprocessing animal carcasses or fractions thereof including meat and bone meal etc., with the objective of providing an alternative means for processing the organic waste material of animal origin while at the same time facilitating the production of fertilizers. The risk of spreading BSE prions or any other prions to animals or humans is thus substantially reduced if not eliminated. The biogas and slurry separation system according to the present invention is preferably integrated with the operations of animal husbandries into a total concept in which the internal and external performances of animal husbandries are optimised. The internal performances concern quality aspects related to the management of the animal houses and include industrial hygiene, animal welfare, gaseous and dust emissions and food safety. The external performances concern mainly energy production and emissions to the environment of nutrients and greenhouse gases and the sale of high quality food product.

2011-02-08

225

Design of a microstructured reactor with integrated heat-exchanger for optimum performance of a highly exothermic reaction  

Microsoft Academic Search

The activity and the heat transfer characteristics of several microstructured reactors have been compared in the ammonia oxidation on Pt catalyst. The main parameters which influence reactor performance are catalyst loading, temperature, and the intrinsic conductivity of the reactor material. In case of aluminum as a reactor material, hot spot temperatures were within 5°C at full conversion of 6vol.% NH3.

E. V Rebrov; M. H. J. M de Croon; J. C Schouten

2001-01-01

226

Performance of the Cascade inertial-confinement-fusion conceptual reactor  

SciTech Connect

A 4.5-m-radius rotating fusion reactor made of silicon carbide and containing a moving 1-m-thick lithium-ceramic granular blanket can produce 3000 MW/sub t/. The blanket operates at high temperature (>1200 K) leading to gross plant efficiencies of up to 60% using a combined helium-gas turbine (Brayton cycle) with a vapor bottoming cycle.

Pitts, J.H.

1984-09-18

227

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

228

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

229

Effects of fuel processing methods on industrial scale biogas-fuelled solid oxide fuel cell system for operating in wastewater treatment plants  

Microsoft Academic Search

The performance of three solid oxide fuel cell (SOFC) systems, fuelled by biogas produced through anaerobic digestion (AD) process, for heat and electricity generation in wastewater treatment plants (WWTPs) is studied. Each system has a different fuel processing method to prevent carbon deposition over the anode catalyst under biogas fuelling. Anode gas recirculation (AGR), steam reforming (SR), and partial oxidation

Siamak Farhad; Yeong Yoo; Feridun Hamdullahpur

2010-01-01

230

Effect of biogas sparging with different membrane modules on membrane fouling in anaerobic submerged membrane bioreactor (AnSMBR).  

PubMed

This study focused on the effect of biogas sparging and different membrane modules such as cylinder shaped, funnel-shaped, and U-shaped on the membrane fouling behavior in a lab-scale submerged anaerobic membrane bioreactor (AnSMBR) which was operated for over 60 days. In order to investigate the membrane fouling behavior, a series of analysis such as SMP, EPS, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), particle size distribution, and filtration resistances were performed. Although the rapid generation of cake layer took placed in case of the absence of biogas sparging, the membrane module design mostly influenced the membrane resistance when biogas sparging was applied. Total resistance was the highest for U-shaped module. The permeate fluxes with biogas sparging were higher about one half and two times than those without biogas sparging. Cylinder-shaped module had the lowest SMP and EPS concentrations followed by U-shaped and funnel-shaped modules under both cases with and without biogas sparging. The total resistances of all membrane modules without biogas sparging were found to be very high compared the pore blocking resistances (Rp). PMID:24234762

Aslan, Mustafa; Saatçi, Yusuf; Hanay, Özge; Hasar, Halil

2014-03-01

231

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

National Technical Information Service (NTIS)

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

A. Lindberg

1992-01-01

232

Performance of coimmobilized yeast and amyloglucosidase in a fluidized bed reactor for fuel ethanol production.  

PubMed

The performance of coimmobilized Saccharomyces cerevisiae and amyloglucosidase (AG) was evaluated in a fluidized-bed reactor. Soluble starch and yeast extracts were used as feed stocks. Conversion of soluble starch streams to ethanol has potential practical applications in corn dry and wet milling and in developmental lignocellulosic processes. The biocatalyst performed well, and demonstrated no significant loss of activity or physical integrity during 10 wk of continuous operation. The reactor was easily operated and required no pH control. No operational problems were encountered from bacterial contaminants even though the reactor was operated under nonsterile conditions over the entire course of experiments. Productivities ranged between 25 and 44 g ethanol/L/h/. The experiments demonstrated that ethanol inhibition and bed loading had significant effects on reactor performance. PMID:9170248

Sun, M Y; Bienkowski, P R; Davison, B H; Spurrier, M A; Webb, O F

1997-01-01

233

Light Water Breeder Reactor fuel element performance characteristics for extending core lifetime: (LWBR Development Program)  

Microsoft Academic Search

The Light Water Breeder Reactor (LWBR) was designed for a lifetime of 18,000 EFPH. Fuel element design was based on performance evaluations demonstrating adequacy for the design lifetime. Continued operation of LWBR beyond design lifetime required re-evaluation of fuel element behavior to determine if continued satisfactory fuel performance could be achieved. The evaluations covered the most limiting fuel performance concerns

B. C. Smith; W. R. Campbell

1987-01-01

234

Microaerobic digestion of sewage sludge on an industrial-pilot scale: the efficiency of biogas desulphurisation under different configurations and the impact of O2 on the microbial communities.  

PubMed

Biogas produced in an industrial-pilot scale sewage sludge reactor (5m(3)) was desulphurised by imposing microaerobic conditions. The H2S concentration removal efficiency was evaluated under various configurations: different mixing methods and O2 injection points. Biogas was entirely desulphurised under all the configurations set, while the O2 demand of the digester decreased over time. Although the H2S removal seemed to occur in the headspace, S(0) (which was found to be the main oxidation product) was scarcely deposited there in the headspace. O2 did not have a significant impact on the digestion performance; the VS removal remained around 47%. Conversely, DGGE revealed that the higher O2 transfer rate to the sludge maintained by biogas recirculation increased the microbial richness and evenness, and caused an important shift in the structure of the bacterial and the archaeal communities in the long term. All the archaeal genera identified (Methanosaeta, Methanospirillum and Methanoculleus) were present under both anaerobic and microaerobic conditions. PMID:24874874

Ramos, I; Pérez, R; Reinoso, M; Torio, R; Fdz-Polanco, M

2014-07-01

235

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

236

Concepts and profitability of biogas production from landscape management grass.  

PubMed

Landscape management grass is generally harvested late, resulting in unfavorable composition for many utilization purposes. This study explores various technical concepts of biogas production and their economic viability. The Lower Oder Valley National Park is taken here as an example. This National Park in North-East Germany comprises large grassland areas with conservation-related restrictions on management. The concepts of biogas production and use considered are: (1) decentralized digestion and use of biogas at five autonomous combined heat and power (CHP) units, (2) decentralized digestion and delivery of the biogas to a centralized CHP unit, (3) decentralized digestion, upgrading of the biogas and feeding into the natural gas grid, and (4) one central biogas plant with centralized CHP unit. Annual costs and revenues of biogas production were calculated for each alternative. Biogas production from landscape management grass meets the conservational demands of late cutting periods and under certain circumstances shows a profit. PMID:20801018

Blokhina, Yulia N; Prochnow, Annette; Plöchl, Matthias; Luckhaus, Christoph; Heiermann, Monika

2011-01-01

237

Performance Assessment of ISS Water Processor Assembly Reactor  

NASA Technical Reports Server (NTRS)

Due to modifications to the ISS waste water composition, the concentration of volatile organics has significantly increased in the feed to the Water Processor Assembly (WPA). In parallel, the oxygen supply pressure increased, resulting in a higher flow rate of oxygen to the WPA. Preliminary testing at Hamilton Sund strand indicated that the higher oxygen flow rate would increase the WPA capacity for volatile organics. Following an analysis of the expected waste water composition, personnel at NASA MSFC and Hamilton Sundstrand conducted a test of a flight-like reactor to assess its capacity for the higher organic loads. The results of this test indicate the WPA can accommodate the expected organic load in the ISS waste water with margin.

Carter, Layne; Tatara, James; Mason, Rich; OConner, Ed; Bedard, John

2004-01-01

238

Biogas cleans up its act  

SciTech Connect

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

Fouhy, K.; Shelley, S.

1997-05-01

239

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

240

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

241

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

242

Feeding approaches for biogas production from animal wastes and industrial effluents  

Microsoft Academic Search

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

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

2000-01-01

243

Treating starch wastewater reclaim bioenergy by EGSB process and high value use of biogas  

Microsoft Academic Search

the expanded granular sludge bed (EGSB) reactor -anoxic\\/aerobic (A\\/O) process has been used for treating highly concentrated starch wastewater, and the biogas produced in EGSB was purified. Under the condition of 35 , ??the COD volume load of EGSB reaches up to 20kg\\/(m 3 ·d), and the combined process removal rates of COD,BOD5 and SS were 98.5%,99.5%and 95%,respectively. After being

Jianguang Liu; Chunyang Zhang; Guanglan Zhang; Hainan Gan

2011-01-01

244

Diversity of the resident microbiota in a thermophilic municipal biogas plant  

Microsoft Academic Search

Biogas plants continuously convert biological wastes mainly into a mixture of methane, CO2 and H2O—a conversion that is carried out by a consortium of bacteria and archaea. Especially in the municipal plants dedicated towards\\u000a waste treatment, the reactor feed may vary considerably, exposing the resident microbiota to a changing variety of substrates.\\u000a To evaluate how and if such changes influence

Agnes Weiss; Valérie Jérôme; Ruth Freitag; Helmut K. Mayer

2008-01-01

245

Reactor instrumentation and control design and performance simulation for SP-100  

NASA Astrophysics Data System (ADS)

The SP-100 flight system will be launched with all primary and secondary lithium in the solid state. Once in orbit, the reactor will be brought critical and maintained at a low power level while the lithium is thawed out. Once the system is thawed out, the reactor power will be controlled to provide the energy source required by the power conversion system to meet the payload electrical power requirements. The Reactor Instrumentation and Control subsystem which includes the reactor control drives, instrumentation and the digital controller provides for the control of the nuclear subsystem to perform these operating maneuvers as well as providing for automatic shutdown and restart under certain off-normal conditions. The design and performance of this system are described.

Meyer, R. A.; Alley, A. D.; Halfen, F. J.; Brynsvold, G. V.

246

Performance Analysis of B4C Used as Shielding Material in China Experiment Fast Reactor  

NASA Astrophysics Data System (ADS)

Hot-pressed boron carbide (B4C) pellet will be used as shielding material in China Experimental Fast Reactor (CEFR) which is the first fast reactor in China. In this paper, two types of B4C sample provided by two different units in China were investigated on out-reactor properties, and one type of sample was studied on irradiation performance. Finally, the evaluation of domestic B4C pellet as shielding material in CEFR was given: the B4C pellets produced in China could satisfy the requirements of CEFR.

Huang, Chen; Zhang, Ruoxian; Xie, Guangshang; Wang, Xiaorong

247

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

248

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

Microsoft Academic Search

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

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

249

Initial in-reactor performance of the Cornell cold neutron source  

Microsoft Academic Search

The Cornell Cold Neutron Beam Facility consists of two major subsystems, a cold neutron source (CNS) and a 13-m-long curved neutron guide. This paper describes the initial in-reactor performance tests of the CNS. The results agree closely with predictions from out-of-reactor tests and meet the design criteria for safety and simplicity of operation. This phase of the project has therefore

S. A. Spern; D. D. Clark; A. G. Atwood

1996-01-01

250

Feasibility Study on Thermal-Hydraulic Performance of Innovative Water Reactor for Flexible Fuel Cycle (FLWR)  

Microsoft Academic Search

R and D project to investigate thermal-hydraulic performance in tight-lattice rod bundles of Innovative Water Reactor for Flexible Fuel Cycle (FLWR) is started at Japan Atomic Energy Agency (JAEA) in collaboration with power company, reactor vendors, universities since 2002. The FLWR can attain the favorable characteristics such as effective utilization of uranium resources, multiple recycling of plutonium, high burn-up and

Ohnuki Akira; Takase Kazuyuki; Kureta Masatoshi; Yoshida Hiroyuki; Tamai Hidesada; Liu Wei; Nakatsuka Toru; Misawa Takeharu; Akimoto Hajime

2006-01-01

251

Physicochemical and biological performance of expanded granular sludge bed reactors treating long-chain fatty acids  

Microsoft Academic Search

The influence of reactor hydrodynamics, temperature and co-substrate on the performance of anaerobic digestion of long-chain fatty acids (LCFA) and sludge characteristics in expanded granular sludge bed (EGSB) reactors was investigated. Based on similar liquid superficial upflow velocities (?up) of 3·4–4 m\\/h in the absence of co-substrate, COD removal efficiencies of 66 and 73% were attained in thermophilic (55°C) runs

Ching-Shyung Hwu; Jules B. van Lier; Gatze Lettinga

1998-01-01

252

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

PubMed

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

Yeganegi, Saeid; Gholampour, Fatemeh

2012-12-01

253

Amount of Biogas and Its Availability for Use in Finland.  

National Technical Information Service (NTIS)

Possibilities of anaerobic treatment of various wastes and the amount of biogas and availabilities for use have been studied The whole biogas potential corresponds to 370 000 tons of oil per annum. The biggest potential for biogas production is in farming...

1983-01-01

254

Jute caddis — A new substrate for biogas production  

Microsoft Academic Search

Biogas containing 55-65 per cent methane can be produced from jute caddis - a lignocellulosic waste of jute mills by anaerobic fermentation, using cattle dung as sole source of inoculum. Biogas production from a lignocellulosic material like jute caddis is a slow but steady process where methane rich biogas comes mostly from hemicellulose and cellulose but not from lignin. Batch

S Banik

255

Prospects for expanded utilization of biogas in Germany  

Microsoft Academic Search

The prospects for expanded utilization of biogas systems in German was analysed, by identifying the operational and policy factors affecting the complete chain of processes from implementation process for biogas plants, through to biogas production and utilization. It was found that the Renewable Energies Act (EEG) and energy tax reliefs provide bases for the support of expanded utilization. Upgrading of

Martina Poeschl; Shane Ward; Philip Owende

2010-01-01

256

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

PubMed

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

Chen, Shaoqing; Chen, Bin

2013-09-01

257

Core performance of equilibrium fast reactors for different coolant materials and fuel types  

Microsoft Academic Search

Parametric studies with several coolant and fuel materials in the equilibrium state are performed for fast reactors in which natural uranium is fed and all of the actinides are confined. Sodium, sodium-potassium, lead, lead-bismuth and helium coolant materials, and oxide, nitride and metal fuels are employed to compare the neutronic characteristics in the equilibrium state. As to the criticality performance,

Akihiko Mizutani; Hiroshi Sekimoto

1998-01-01

258

High-performance core concept study for High Temperature Engineering Test Reactor.  

National Technical Information Service (NTIS)

A study of the high-performance core concept was carried out for the High Temperature Engineering Test Reactor (HTTR) from the viewpoint of nuclear and thermal-hydraulics design. The high-performance core should have high irradiation test capability and p...

K. Yamashita M. Nakano N. Nojiri N. Fujimoto K. Sawa

1997-01-01

259

Taguchi Based Performance and Reliability Improvement of an Ion Chamber Amplifier for Enhanced Nuclear Reactor Safety  

Microsoft Academic Search

An ion chamber amplifier (ICA) is used as a safety device for neutronic power (flux) measurement in regulation and protection systems of nuclear reactors. Therefore, performance reliability of an ICA is an important issue. Appropriate quality engineering is essential to achieve a robust design and performance of the ICA circuit. It is observed that the low input bias current operational

R. D. Kulkarni; Vivek Agarwal

2008-01-01

260

FUZZY MODELLING APPLIED TO AN UASB REACTOR  

Microsoft Academic Search

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

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

261

Hydrodynamics and microbial physiology affecting performance of a new MBR, membrane-coupled high-performance compact reactor  

Microsoft Academic Search

In this study, hydrodynamics and physiology of microorganisms were investigated in a new type membrane bioreactor, MHCR, which is a membrane coupled HCR (High performance Compact Reactor) having very high COD removal efficiency. The degree of interference caused by inserting a submerged membrane was evaluated quantitatively by measuring the air suction rate and overall oxygen transfer coefficient (kL,a). Despite such

Jong-Sang Park; Kyung-Min Yeon; Chung-Hak Lee

2005-01-01

262

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

263

Modelling biogas production of solid waste: application of the BGP model to a synthetic landfill  

NASA Astrophysics Data System (ADS)

Production of biogas as a result of the decomposition of organic matter included on solid waste landfills is still an issue to be understood. Reports on this matter are rarely included on the engineering construction projects of solid waste landfills despite it can be an issue of critical importance while operating the landfill and after its closure. This paper presents an application of BGP (Bio-Gas-Production) model to a synthetic landfill. The evolution in time of the concentrations of the different chemical compounds of biogas is studied. Results obtained show the impact on the air quality of different management alternatives which are usually performed in real landfills.

Rodrigo-Ilarri, Javier; Segura-Sobrino, Francisco

2013-04-01

264

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

265

A review of boiling water reactor water chemistry: Science, technology, and performance  

SciTech Connect

Boiling water reactor (BWR) water chemistry (science, technology, and performance) has been reviewed with an emphasis on the relationships between BWR water quality and corrosion fuel performance, and radiation buildup. A comparison of Nuclear Regulatory Commission (NRC) Regulatory Guide 1.56, the Boiling Water Reactor Owners Group (BWROG) Water Chemistry Guidelines, and Plant Technical Specifications showed that the BWROG Guidelines are more stringent than the NRC Regulatory Guide, which is almost identical to Plant Technical Specifications. Plant performance with respect to BWR water chemistry has shown dramatic improvements in recent years. Up until 1979 BWRs experienced an average of 3.0 water chemistry incidents per reactor-year. Since 1979 the water chemistry technical specifications have been violated an average of only 0.2 times per reactor-year, with the most recent data from 1986-1987 showing only 0.05 violations per reactor-year. The data clearly demonstrate the industry-wide commitment to improving water quality in BWRs. In addition to improving water quality, domestic BWRs are beginning to switch to hydrogen water chemistry (HWC), a remedy for intergranular stress corrosion cracking. Three domestic BWRs are presently operating on HWC, and fourteen more have either performed HWC mini tests or are in various stages of HWC implementation. This report includes a detailed review of HWC science and technology as well as areas in which further research on BWR chemistry may be needed. 43 refs., 30 figs., 8 tabs.

Fox, M.J.

1989-02-01

266

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

267

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

268

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

269

Reviewing real-time performance of nuclear reactor safety systems  

Microsoft Academic Search

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

Preckshot

1993-01-01

270

Effect of substrate and cation requirement on anaerobic volatile fatty acid conversion rates at elevated biogas pressure.  

PubMed

This work studied the anaerobic conversion of neutralized volatile fatty acids (VFA) into biogas under Autogenerative High Pressure Digestion (AHPD) conditions. The effects of the operating conditions on the biogas quality, and the substrate utilisation rates were evaluated using 3 AHPD reactors (0.6 L); feeding a concentration of acetate and VFA (1-10 g COD/L) corresponding to an expected pressure increase of 1-20 bar. The biogas composition improved with pressure up to 4.5 bar (>93% CH4), and stabilized at 10 and 20 bar. Both, acetotrophic and hydrogenotrophic methanogenic activity was observed. Substrate utilisation rates of 0.2, 0.1 and 0.1 g CODCH4/g VSS/d for acetate, propionate and butyrate were found to decrease by up to 50% with increasing final pressure. Most likely increased Na(+)-requirement to achieve CO2 sequestration at higher pressure rather than end-product inhibition was responsible. PMID:24152787

Lindeboom, Ralph E F; Ferrer, Ivet; Weijma, Jan; van Lier, Jules B

2013-12-01

271

Performance of two-stage vegetable waste anaerobic digestion depending on varying recirculation rates.  

PubMed

Vegetable waste, which characterized by high moisture content, was evaluated as a substrate for biogas production. The effects of recirculation rate (RR) on the performance of two-stage anaerobic digestion were investigated. The system was operated at an organic loading rate of 1.7 g VS/L/d with varying RRs (0, 0.6, 1, and 1.4). Results demonstrated that volumetric biogas production rates in acidogenic reactor increased from approximately 0.2 7 L/L/d to 0.97 L/L/d, when pH is increased from approximately 5.1 to 6.7. These indicate that recirculation of alkaline effluent from the methanogenic reactor helps create a favorable condition for biogas production in the acidogenic reactor. The decrease in chemical oxygen demand (COD) concentrations from approximately 21,000 mg/L to 6800 mg/L was also observed in the acidogenic reactor. This condition may be attributed to dilution under recirculation. The dynamics between hydrolysis and methanogenesis under recirculation indicated that mass transfer capacity between two-stage reactors improved. PMID:24759642

Zuo, Zhuang; Wu, Shubiao; Zhang, Wanqin; Dong, Renjie

2014-06-01

272

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

National Technical Information Service (NTIS)

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

E. Stroem T. Ekeborg

1991-01-01

273

Metal-organic frameworks for upgrading biogas via CO2 adsorption to biogas green energy.  

PubMed

In the midst of the global climate change phenomenon, mainly caused by fossil fuel burning to provide energy for our daily life and discharge of CO2 into the atmosphere, biogas is one of the important renewable energy sources that can be upgraded and applied as a fuel source for energy in daily life. The advantages of the production of hybrid materials, metal-organic framework (MOF) adsorbents, expected for the biogas upgrading, rely on the bulk separation of CO2 under near-ambient conditions. This review highlights the challenges for MOF adsorbents, which have the greatest upgrading abilities for biogas via selective passage of methane. The key factors improving the ideal MOF materials for these high CO2 capture and selectivity uses for biogas upgrading to produce bio-methane and reduce fossil-fuel CO2 emission will be discussed. PMID:24045837

Chaemchuen, Somboon; Kabir, Nawsad Alam; Zhou, Kui; Verpoort, Francis

2013-12-21

274

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

275

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

276

Experimental study of two-phase pump performance using a full size nuclear reactor pump  

Microsoft Academic Search

The performance of a full-size nuclear reactor primary heat transport pump was investigated experimentally under high pressure, steam–water two-phase flow conditions. A new set of two-phase pump performance test data was obtained with local void fraction and mass flux measurements at the pump suction. The effects of suction temperature and initial flow conditions on the two-phase pump performance characteristics were

A. M. C. Chan; M. Kawaji; H. Nakamura; Y. Kukita

1999-01-01

277

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

278

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

279

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

280

Biogas/biofertilizer business handbook (third edition)  

SciTech Connect

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

Arnott, M.

1985-07-01

281

Conversion of biomass to biogas and fertilizer  

SciTech Connect

Both the scarcity and high cost of conventional sources of energy have stimulated worldwide search for alternative sources of energy. Solar energy is more widely distributed than any other form of energy. Solar energy fixed by green vegetation photosynthetically into organic plant matter can be converted by biochemical reactions into combustible biogas.

Narasimhamurty, G.S.R.

1983-12-01

282

Modeling biogas production at landfill site  

Microsoft Academic Search

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

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

1999-01-01

283

Full scale fluidized bed anaerobic reactor for domestic wastewater treatment: performance, sludge production and biofilm.  

PubMed

This paper describes the performance, sludge production and biofilm characteristics of a full scale fluidized bed anaerobic reactor (32 m3) for domestic wastewater treatment. The reactor was operated with 10.5 m x h(-1) upflow velocity, 3.2 h hydraulic retention time, and recirculation ratio of 0.85 and it presented removal efficiencies of 71+/-8% of COD and 77+/-14% of TSS. During the apparent steady-state period, specific sludge production and sludge age in the reactor were (0.116+/-0.033) kgVSS. kgCOD(-1) and (12+/-5)d, respectively. Biofilm formed in the reactor presented two different patterns: one of them at the beginning of the colonization and the other of mature biofilm. These different colonization patterns are due to bed stratification in the reactor, caused by the difference in local-energy dissipation rates along the reactor's height, and density, shape, etc. of the bioparticles. The biofilm population is formed mainly of syntrophic consortia among sulfate reducing bacteria, methanogenic archaea such as Methanobacterium and Methanosaeta-like cells. PMID:15303757

Mendonça, N M; Niciura, C L; Gianotti, E P; Campos, J R

2004-01-01

284

Anaerobic digestion of corn stovers for methane production in a novel bionic reactor.  

PubMed

To improve the biogas production from corn stovers, a new bionic reactor was designed and constructed. The bionic reactor simulated the rumen digestion of ruminants. The liquid was separated from corn stovers and refluxed into corn stovers again, which simulated the undigested particles separated from completely digested materials and fed back again for further degradation in ruminant stomach. Results showed that the bionic reactor was effective for anaerobic digestion of corn stovers. The liquid amount and its reflux showed an obvious positive correlation with biogas production. The highest biogas production rate was 21.6ml/gVS-addedd, and the total cumulative biogas production was 256.5ml/gVS-added. The methane content in biogas ranged from 52.2% to 63.3%. The degradation of corn stovers were greatly enhanced through simulating the animal digestion mechanisms in this bionic reactor. PMID:24923659

Zhang, Meixia; Zhang, Guangming; Zhang, Panyue; Fan, Shiyang; Jin, Shuguang; Wu, Dan; Fang, Wei

2014-08-01

285

Design consideration and economic analysis of a community size biogas unit  

SciTech Connect

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

Abbus, S.P.

1983-12-01

286

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

PubMed Central

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

2013-01-01

287

Relative performance properties of the ORNL Advanced Neutron Source Reactor with reduced enrichment fuels  

Microsoft Academic Search

Three cores for the Advanced Neutron Source reactor, differing in size, enrichment, and uranium density in the fuel meat, have been analyzed. Performance properties of the reduced enrichment cores are compared with those of the HEU reference configuration. Core lifetime estimates suggest that none of these configurations will operate for the design goal of 17 days at 330 MW. With

M. M. Bretscher; J. R. Deen; N. A. Hanan; J. E. Matos; S. C. Mo; R. B. Pond; A. Travelli; W. L. Woodruff

1994-01-01

288

In-reactor performance of methods to control fuel-cladding chemical interaction. [LMFBR  

Microsoft Academic Search

Inner surface corrosion of austenitic stainless steel cladding by oxygen and reactive fission product elements requires a 50 ..mu..m wastage allowance in current FBR reference oxide fuel pin design. Elimination or reduction of this wastage allowance could result in better reactor efficiency and economics through improvements in fuel pin performance and reliability. Reduction in cladding thickness and replacement of equivalent

E. T. Weber; R. L. Gibby; C. N. Wilson; L. A. Lawrence; M. G. Adamson

1979-01-01

289

Ordered mesoporous carbon nanochannel reactors for high-performance Fischer-Tropsch synthesis.  

PubMed

A hexagonally ordered mesoporous carbon, CMK-3, was utilized as a support for a Fischer-Tropsch catalyst. Each array of elongated pore structures with Co nanoparticles can be regarded as a nanochannel reactor. Due to the pore confinement and the hydrophobic nature of the support, this catalyst demonstrated excellent catalytic performance. PMID:23482917

Ha, Kyoung-Su; Kwak, Geunjae; Jun, Ki-Won; Hwang, Jongkook; Lee, Jinwoo

2013-06-01

290

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

291

Performance of Small Nuclear Reactor Primary Coolant Pumps under Blowdown Conditions.  

National Technical Information Service (NTIS)

Performance results for small, canned rotor nuclear reactor primary coolant pumps under one- and two-phase flow conditions were obtained in the Loss-of-Fluid Test facility at the Idaho National Engineering Laboratory. Calculation of pump behavior during t...

J. A. Hunter P. A. Harris

1978-01-01

292

Application of immobilized enzyme reactor in on-line high performance liquid chromatography: A review  

Microsoft Academic Search

This review summarizes all the research efforts in the last decade (1994–2003) that have been spent to the various application of immobilized enzyme reactor (IMER) in on-line high performance liquid chromatography (HPLC). All immobilization procedures including supports, kind of assembly into chromatographic system and methods are described. The effect of immobilization on enzymatic properties and stability of biocatalysts is considered.

Anna Maria Girelli; Enrico Mattei

2005-01-01

293

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

294

Effect of Different Structural Materials on Neutronic Performance of a Hybrid Reactor  

NASA Astrophysics Data System (ADS)

Selection of structural material for a fusion-fission (hybrid) reactor is very important by taking into account of neutronic performance of the blanket. Refractory metals and alloys have much higher operating temperatures and neutron wall load (NWL) capabilities than low activation materials (ferritic/martensitic steels, vanadium alloys and SiC/SiC composites) and austenitic stainless steels. In this study, effect of primary candidate refractory alloys, namely, W-5Re, T111, TZM and Nb-1Zr on neutronic performance of the hybrid reactor was investigated. Neutron transport calculations were conducted with the help of SCALE 4.3 System by solving the Boltzmann transport equation with code XSDRNPM. Among the investigated structural materials, tantalum had the worst performance due to the fact that it has higher neutron absorption cross section than others. And W-5Re and TZM having similar results showed the best performance.

Übeyli, Mustafa; Tel, Eyyüp

2003-06-01

295

A Comparison of Photocatalytic Oxidation Reactor Performance for Spacecraft Cabin Trace Contaminant Control Applications  

NASA Technical Reports Server (NTRS)

Photocatalytic oxidation (PCO) is a maturing process technology that shows potential for spacecraft life support system application. Incorporating PCO into a spacecraft cabin atmosphere revitalization system requires an understanding of basic performance, particularly with regard to partial oxidation product production. Four PCO reactor design concepts have been evaluated for their effectiveness for mineralizing key trace volatile organic com-pounds (VOC) typically observed in crewed spacecraft cabin atmospheres. Mineralization efficiency and selectivity for partial oxidation products are compared for the reactor design concepts. The role of PCO in a spacecraft s life support system architecture is discussed.

Perry, Jay L.; Frederick, Kenneth R.; Scott, Joseph P.; Reinermann, Dana N.

2011-01-01

296

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

Microsoft Academic Search

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

R. E. Einziger; B. R. Seidel

1980-01-01

297

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

Microsoft Academic Search

This paper developed a design and investigated the performance of 38 kWe turbo-machine unit for space nuclear reactor power systems with Closed Brayton Cycle (CBC) energy conversion. The compressor and turbine of this unit are scaled versions of the NASA's BRU developed in the sixties and seventies. The performance results of turbo-machine unit are calculated for rotational speed up to

Bruno M. Gallo; Mohamed S. El-Genk

2008-01-01

298

Biogas production and methanogenic archaeal community in mesophilic and thermophilic anaerobic co-digestion processes.  

PubMed

Over 258 Mt of solid waste are generated annually in Europe, a large fraction of which is biowaste. Sewage sludge is another major waste fraction. In this study, biowaste and sewage sludge were co-digested in an anaerobic digestion reactor (30% and 70% of total wet weight, respectively). The purpose was to investigate the biogas production and methanogenic archaeal community composition in the anaerobic digestion reactor under meso- (35-37 °C) and thermophilic (55-57 °C) processes and an increasing organic loading rate (OLR, 1-10 kg VS m(-3) d(-1)), and also to find a feasible compromise between waste treatment capacity and biogas production without causing process instability. In summary, more biogas was produced with all OLRs by the thermophilic process. Both processes showed a limited diversity of the methanogenic archaeal community which was dominated by Methanobacteriales and Methanosarcinales (e.g. Methanosarcina) in both meso- and thermophilic processes. Methanothermobacter was detected as an additional dominant genus in the thermophilic process. In addition to operating temperatures, the OLRs, the acetate concentration, and the presence of key substrates like propionate also affected the methanogenic archaeal community composition. A bacterial cell count 6.25 times higher than archaeal cell count was observed throughout the thermophilic process, while the cell count ratio varied between 0.2 and 8.5 in the mesophilic process. This suggests that the thermophilic process is more stable, but also that the relative abundance between bacteria and archaea can vary without seriously affecting biogas production. PMID:24837280

Yu, D; Kurola, J M; Lähde, K; Kymäläinen, M; Sinkkonen, A; Romantschuk, M

2014-10-01

299

Light water reactor fuel performance modeling and multi-dimensional simulation  

NASA Astrophysics Data System (ADS)

Light water reactor fuel is a multicomponent system required to produce thermal energy through the fission process, efficiently transfer the thermal energy to the coolant system, and provide a barrier to fission product release by maintaining structural integrity. The operating conditions within a reactor induce complex multi-physics phenomena that occur over time scales ranging from less than a microsecond to years and act over distances ranging from inter-atomic spacing to meters. These conditions impose challenging and unique modeling, simulation, and verification data requirements in order to accurately determine the state of the fuel during its lifetime in the reactor. The capabilities and limitations of the current engineering-scale one-dimensional and two-dimensional fuel performance codes is discussed and the challenges of employing higher level fidelity atomistic modeling techniques such as molecular dynamics and phase-field simulations is presented.

Rashid, Joseph Y. R.; Yagnik, Suresh K.; Montgomery, Robert O.

2011-08-01

300

Performance Assessment of the Commercial CFD Software for the Prediction of the Reactor Internal Flow  

NASA Astrophysics Data System (ADS)

As the computer hardware technology develops the license applicants for nuclear power plant use the commercial CFD software with the aim of reducing the excessive conservatism associated with using simplified and conservative analysis tools. Even if some of CFD software developer and its user think that a state of the art CFD software can be used to solve reasonably at least the single-phase nuclear reactor problems, there is still limitation and uncertainty in the calculation result. From a regulatory perspective, Korea Institute of Nuclear Safety (KINS) is presently conducting the performance assessment of the commercial CFD software for nuclear reactor problems. In this study, in order to examine the validity of the results of 1/5 scaled APR+ (Advanced Power Reactor Plus) flow distribution tests and the applicability of CFD in the analysis of reactor internal flow, the simulation was conducted with the two commercial CFD software (ANSYS CFX V.14 and FLUENT V.14) among the numerous commercial CFD software and was compared with the measurement. In addition, what needs to be improved in CFD for the accurate simulation of reactor core inlet flow was discussed.

Lee, Gong Hee; Bang, Young Seok; Woo, Sweng Woong; Kim, Do Hyeong; Kang, Min Ku

2014-06-01

301

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

302

Light Water Breeder Reactor fuel element performance characteristics for extending core lifetime: (LWBR Development Program)  

SciTech Connect

The Light Water Breeder Reactor (LWBR) was designed for a lifetime of 18,000 EFPH. Fuel element design was based on performance evaluations demonstrating adequacy for the design lifetime. Continued operation of LWBR beyond design lifetime required re-evaluation of fuel element behavior to determine if continued satisfactory fuel performance could be achieved. The evaluations covered the most limiting fuel performance concerns for extended lifetime: Zircaloy cladding corrosion, hydriding, flow-induced vibratory wear, cladding deformation into unsupported axial gaps, pellet-cladding interaction (PCI) during controlled and accidental power increases, rod elongation, and rod-to-rod clearance reduction due to rod bowing. Results of the evaluations are described. Based on these results, limits on reactor operating power, pressure, and temperature during extended lifetime were defined to allow LWBR to achieve over 29,000 EFPH of satisfactory operation.

Smith, B.C.; Campbell, W.R.

1987-10-01

303

Improvement of membrane performances to enhance the yield of vanillin in a pervaporation reactor.  

PubMed

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

304

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.

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

2014-01-01

305

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

306

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

307

Siloxane removal from biogas by biofiltration: biodegradation studies  

Microsoft Academic Search

Recently a lot of attention has been focused on volatile methyl siloxanes (VMSs) in biogas because of the costly problems\\u000a deriving from the formation of silicate-based deposits in biogas-fuelled power plant equipments. Currently, VMSs are removed\\u000a from biogas with high operational costs by adsorption on activated carbons. Biofiltration could be a cost-effective and environmentally\\u000a friendly alternative to current technologies, leading

Francesca Accettola; Georg M. Guebitz; Rainer Schoeftner

2008-01-01

308

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

309

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

310

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

311

Thermic model to predict biogas production in unheated fixed-dome digesters buried in the ground.  

PubMed

In many developing countries, simple biogas digesters are used to produce energy for domestic purposes from anaerobic digestion of animal manure. We developed a simple, one-dimensional (1-D), thermal model with easily available input data for unheated, unstirred, uninsulated, fixed-dome digesters buried in the soil to study heat transfer between biogas digester and its surroundings. The predicted temperatures in the dome, biogas, and slurry inside the digester and the resulting biogas production are presented and validated. The model was well able to estimate digester temperature (linear slope nearly 1, R(2) = 0.96). Model validation for methane production gave root-mean-square error (RMSE) of 54.4 L CH4 digester(-1) day(-1) and relative-root-mean-square errors (rRMSEP(%)) of 35.4%. The validation result was considerably improved if only using winter data (RMSE = 26.1 L CH4 digester(-1) day(-1); rRMSEP(%) = 17.7%). The model performed satisfactorily in light of the uncertainties attached to it. Since unheated digesters suffer critically low methane production during the winter, the model could be particularly useful for assessing methane production and for improving the ability of unheated digesters to provide sufficient energy during cold periods. PMID:24517412

Terradas-Ill, Georgina; Pham, Cuong H; Triolo, Jin M; Martí-Herrero, Jaime; Sommer, Sven G

2014-03-18

312

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

313

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

314

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

315

Climate balance of biogas upgrading systems.  

PubMed

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(2). PMID:19783421

Pertl, A; Mostbauer, P; Obersteiner, G

2010-01-01

316

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

317

[Performance of lab-scale SPAC anaerobic bioreactor with high loading rate].  

PubMed

The performance of a novel anaerobic bioreactor, spiral automatic circulation (SPAC) reactor, was investigated in lab-scale. The results showed that the average COD removal efficiency was 93.6% (91.1%-95.7%), with influent concentration increased from 8000 mg/L to 20 000 mg/L, at 30 degrees C and hydraulic retention time (HRT) of 12 h. The removal efficiency remained at 96.0%-78.7% when HRT was shortened from 5.95 h to 1.57 h, as the influent concentration was kept constantly at 20 000 mg/L. The highest organic loading rate (OLR), volumetric COD removal rate and volumetric biogas production of the SPAC reactor were 306 gCOD/(L x d), 240 g/(L x d) and 131 L/(L x d), respectively. When increasing influent COD concentration (from 8000 mg/L to 20 000 mg/L), the effluent COD concentration maintained at low level (852 mg/L for average) with volumetric COD removal rate increased by 162% and volumetric biogas production increased by 119%. With reduced HRT (from 5.95 h to 1.57 h), the volumetric COD removal rate and volumetric biogas production were increased by 191% and 195%, respectively. The SPAC reactor shows good performances in adapting the continuous change of influent COD and HRT. PMID:18998544

Chen, Jianwei; Tang, Chongjian; Zheng, Ping; Zhang, Lei

2008-08-01

318

Performance test of a 6-stage continuous reactor for palm methyl ester production  

Microsoft Academic Search

Effects of residence time (3–12min), stirrer speed (0–800rpm), and NaOH concentration (0.25–1.0wt% of oil) on the production performance of the designed 6-stage continuous reactor (2.272l) for transesterification of palm oil were investigated at molar ratio of methanol to oil of 6:1 and temperature of 60°C. Higher stirrer speed increased the reaction rate up to an appropriate speed but excessive stirrer

T. Leevijit; C. Tongurai; G. Prateepchaikul; W. Wisutmethangoon

2008-01-01

319

Effect of Different Structural Materials on Neutronic Performance of a Hybrid Reactor  

Microsoft Academic Search

Selection of structural material for a fusion–fission (hybrid) reactor is very important by taking into account of neutronic performance of the blanket. Refractory metals and alloys have much higher operating temperatures and neutron wall load (NWL) capabilities than low activation materials (ferritic\\/martensitic steels, vanadium alloys and SiC\\/SiC composites) and austenitic stainless steels. In this study, effect of primary candidate refractory

Mustafa Übeyli; Eyyüp Tel

2003-01-01

320

PERFORMANCE OF TUBULAR-TYPE OPTICAL FIBER REACTOR FOR DECOMPOSITION OF VOCS IN GASEOUS PHASE  

Microsoft Academic Search

Photocatalytic decomposition of volatile organic compounds, (VOCs) 2-propanol, trichloroethylene (TCE) and benzene, was studied using a tubular-type optical fiber photoreactor with only one TiO2-coated fiber located at the centerline of the reactor. The effects of initial concentration ranged from 0.005-0.055 kg m-3, ultraviolet light intensity from 0-2700 J s-1 m-2 and relative humidity from 5-50% on the performance of the

Chih-Ming Ma; Young Ku; Yiang-Chen Chou; Fu-Tien Jeng

321

Performance of small nuclear reactor primary coolant pumps under blowdown conditions. [PWR  

Microsoft Academic Search

Performance results for small, canned rotor nuclear reactor primary coolant pumps under one- and two-phase flow conditions were obtained in the Loss-of-Fluid Test facility at the Idaho National Engineering Laboratory. Calculation of pump behavior during the changing flow conditions (blowdown) along with experimental results are presented for testing where the pumps were allowed to coast down. Additional experiment results for

J. A. Hunter; P. A. Harris

1978-01-01

322

Comparative performance of fixed-film biological filters: Application of reactor theory  

USGS Publications Warehouse

Nitrification is classified as a two-step consecutive reaction where R1 represents the rate of formation of the intermediate product NO2-N and R2 represents the rate of formation of the final product NO3-N. The relative rates of R1 and R2 are influenced by reactor type characterized hydraulically as plug-flow, plug-flow with dispersion and mixed-flow. We develop substrate conversion models for fixed-film biofilters operating in the first-order kinetic regime based on application of chemical reactor theory. Reactor type, inlet conditions and the biofilm kinetic constants Ki (h-1) are used to predict changes in NH4-N, NO2-N, NO3-N and BOD5. The inhibiting effects of the latter on R1 and R2 were established based on the ?? relation, e.g.:{A formula is presented}where BOD5,max is the concentration that causes nitrification to cease and N is a variable relating Ki to increasing BOD5. Conversion models were incorporated in spreadsheet programs that provided steady-state concentrations of nitrogen and BOD5 at several points in a recirculating aquaculture system operating with input values for fish feed rate, reactor volume, microscreen performance, make-up and recirculating flow rates. When rate constants are standardized, spreadsheet use demonstrates plug-flow reactors provide higher rates of R1 and R2 than mixed-flow reactors thereby reducing volume requirements for target concentrations of NH4-N and NO2-N. The benefit provided by the plug-flow reactor varies with hydraulic residence time t as well as the effective vessel dispersion number, D/??L. Both reactor types are capable of providing net increases in NO2-N during treatment but the rate of decrease in the mixed-flow case falls well behind that predicted for plug-flow operation. We show the potential for a positive net change in NO2-N increases with decreases in the dimensionless ratios K2, (R2 )/K1,( R1 ) and [NO2-N]/[NH4-N] and when the product K1, (R1) t provides low to moderate NH4-N conversions. Maintaining high levels of the latter reduces the effective reactor utilization rate (%) defined here as (RNavg/RNmax)100 where RNavg is the mean reactive nitrogen concentration ([NH4-N] + [NO2-N]) within the reactor, and RNmax represents the feed concentration of the same. Low utilization rates provide a hedge against unexpected increases in substrate loading and reduce water pumping requirements but force use of elevated reactor volumes. Further ?? effects on R1 and R2 can be reduced through use of a tanks-in-series versus a single mixed-flow reactor configuration and by improving the solids removal efficiency of microscreen treatment.

Watten, B. J.; Sibrell, P. L.

2006-01-01

323

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

SciTech Connect

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

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

2012-07-01

324

Quantification of syntrophic acetate-oxidizing microbial communities in biogas processes  

PubMed Central

Changes in communities of syntrophic acetate-oxidizing bacteria (SAOB) and methanogens caused by elevated ammonia levels were quantified in laboratory-scale methanogenic biogas reactors operating at moderate temperature (37°C) using quantitative polymerase chain reaction (qPCR). The experimental reactor was subjected to gradually increasing ammonia levels (0.8–6.9 g NH4+-N l?1), whereas the level of ammonia in the control reactor was kept low (0.65–0.90 g NH4+-N l?1) during the entire period of operation (660 days). Acetate oxidation in the experimental reactor, indicated by increased production of 14CO2 from acetate labelled in the methyl carbon, occurred when ammonia levels reached 5.5 and 6.9 g NH4+-N l?1. Syntrophic acetate oxidizers targeted by newly designed qPCR primers were Thermacetogenium phaeum, Clostridium ultunense, Syntrophaceticus schinkii and Tepidanaerobacter acetatoxydans. The results showed a significant increase in abundance of all these bacteria except T. phaeum in the ammonia-stressed reactor, coincident with the shift to syntrophic acetate oxidation. As the abundance of the bacteria increased, a simultaneous decrease was observed in the abundance of aceticlastic methanogens from the families Methanosaetaceae and Methanosarcinaceae. qPCR analyses of sludge from two additional high ammonia processes, in which methane production from acetate proceeded through syntrophic acetate oxidation (reactor SB) or through aceticlastic degradation (reactor DVX), demonstrated that SAOB were significantly more abundant in the SB reactor than in the DVX reactor.

Westerholm, Maria; Dolfing, Jan; Sherry, Angela; Gray, Neil D; Head, Ian M; Schnurer, Anna

2011-01-01

325

The Bosch Process-Performance of a Developmental Reactor and Experimental Evaluation of Alternative Catalysts  

NASA Technical Reports Server (NTRS)

Bosch-based reactors have been in development at NASA since the 1960's. Traditional operation involves the reduction of carbon dioxide with hydrogen over a steel wool catalyst to produce water and solid carbon. While the system is capable of completely closing the loop on oxygen and hydrogen for Atmosphere Revitalization, steel wool requires a reaction temperature of 650C or higher for optimum performance. The single pass efficiency of the reaction over steel wool has been shown to be less than 10% resulting in a high recycle stream. Finally, the formation of solid carbon on steel wool ultimately fouls the catalyst necessitating catalyst resupply. These factors result in high mass, volume and power demands for a Bosch system. Interplanetary transportation and surface exploration missions of the moon, Mars, and near-earth objects will require higher levels of loop closure than current technology cannot provide. A Bosch system can provide the level of loop closure necessary for these long-term missions if mass, volume, and power can be kept low. The keys to improving the Bosch system lie in reactor and catalyst development. In 2009, the National Aeronautics and Space Administration refurbished a circa 1980's developmental Bosch reactor and built a sub-scale Bosch Catalyst Test Stand for the purpose of reactor and catalyst development. This paper describes the baseline performance of two commercially available steel wool catalysts as compared to performance reported in the 1960's and 80's. Additionally, the results of sub-scale testing of alternative Bosch catalysts, including nickel- and cobalt-based catalysts, are discussed.

Abney, Morgan B.; Mansell, J. Matthew

2010-01-01

326

Testing of Passive Safety System Performance for Higher Power Advanced Reactors  

SciTech Connect

This report describes the results of NERI research on the testing of advanced passive safety performance for the Westinghouse AP1000 design. The objectives of this research were: (a) to assess the AP1000 passive safety system core cooling performance under high decay power conditions for a spectrum of breaks located at a variety of locations, (b) to compare advanced thermal hydraulic computer code predictions to the APEX high decay power test data and (c) to develop new passive safety system concepts that could be used for Generation IV higher power reactors.

brian G. Woods; Jose Reyes, Jr.; John Woods; John Groome; Richard Wright

2004-12-31

327

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

328

Changes in process performance and microbial characteristics of retained sludge during low-temperature operation of an EGSB reactor  

Microsoft Academic Search

A lab-scale expanded granular sludge bed (EGSB) reactor was seeded with granular sludge and operated to investigate the influence of temperature decrease on both process performance and the microbial community structure of the granular sludge. Synthetic wastewater containing sucrose and volatile fatty acids was used as feed. The EGSB reactor was brought online at a starting temperature of 15°C and

Wilasinee Yoochatchaval; Ikuo Tsushima; Akiyoshi Ohashi; Hideki Harada; Takashi Yamaguchi; Nobuo Araki; Kazuaki Syutsubo

2008-01-01

329

Reactor performance and microbial community dynamics during anaerobic biological treatment of wastewaters at 16–37 °C  

Microsoft Academic Search

The anaerobic biological treatment of volatile fatty acid (VFA) – and sucrose – based wastewaters was investigated in two anaerobic bioreactors, R1 and R2, over a 300-day trial period. During the trial, the operating temperature of both reactors was lowered, in a stepwise fashion, from 37 to 16 °C. The VFA-fed reactor maintained an excellent level of performance, regardless of

Sharon McHugh; Micheal Carton; Gavin Collins; Vincent O'Flaherty

2004-01-01

330

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

PubMed

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

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

2012-03-01

331

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

332

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

SciTech Connect

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

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

2007-01-30

333

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

PubMed Central

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

Kundu, Pradyut; Debsarkar, Anupam; Mukherjee, Somnath

2013-01-01

334

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

335

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

SciTech Connect

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

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

2012-01-01

336

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

Microsoft Academic Search

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

Conklin

1990-01-01

337

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

338

Feasibility Study of Biogas Production from Energy Crops.  

National Technical Information Service (NTIS)

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

L. Brolin L. Thyselius M. Johansson

1988-01-01

339

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...

340

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.

341

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

342

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

343

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

344

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

345

MAXIMIZING SLUDGE AND BIOGAS PRODUCTION FOR COUNTERACTING GLOBAL WARMING  

Microsoft Academic Search

Can wastewater treatment contribute to counteract global warming? Increased biogas production for substituting fossil fuel is one possibility. However, using maximum amount of the carbon source for biogas production there will be no carbon source for biological nutrient removal. This will need development of new methods for nutrient removal without carbon source, for which struvite precipitation and can anammox be

E. Levlin

346

Concepts and profitability of biogas production from landscape management grass  

Microsoft Academic Search

Landscape management grass is generally harvested late, resulting in unfavorable composition for many utilization purposes. This study explores various technical concepts of biogas production and their economic viability. The Lower Oder Valley National Park is taken here as an example. This National Park in North-East Germany comprises large grassland areas with conservation-related restrictions on management. The concepts of biogas production

Yulia N. Blokhina; Annette Prochnow; Matthias Plöchl; Christoph Luckhaus; Monika Heiermann

2011-01-01

347

Biogas Purification Process to Increase Gen-Set Efficiency  

NASA Astrophysics Data System (ADS)

Because of global issue about limited energy, biogas was one of alternative energy and save energy in the world which produced from biomass especially from cow manure. Most of biogas which produced from cow manure contains 40-75% methane as energy resources and another gas as impurities. Methane concentration of biogas has relation with biogas energy value, especially for application as fuel of electricity conversion using gen-set. For increasing gen-set efficiency can be held by increasing methane concentration of biogas using biogas purification process. Biogas purification process can be held by adsorption system which using activated zeolite as absorber. After biogas through the purification system, methane concentration was increasing and impacting to gen-set efficiency especially voltage value was increasing until 22 times in average better than without purification and keeping power stability, so it will produce electricity conversion until 39,07% of practical and 38,09% of equation calculation from maximum electric power output of gen-set.

Krido Wahono, Satriyo; Maryana, Roni; Kismurtono, M.

2009-09-01

348

POTENTIAL OF BIOGAS PRODUCTION IN SUSTAINABLE BIOREFINERY CONCEPTS  

Microsoft Academic Search

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

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

349

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

Microsoft Academic Search

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

Kenji Arai; Seijiro Suzuki; Mikihide Nakamaru; Hideaki Heki

2003-01-01

350

Analysis of factors affecting the performance of partial nitrification in a sequencing batch reactor.  

PubMed

The objective of this study was to analyze the factors affecting the performance of partial nitrification in a sequencing batch reactor. During a 140-day long-term operation, influent pH value, dissolved oxygen (DO), and chemical oxygen demand/nitrogen (COD/N) ratio were selected as operating factors to evaluate the maintenance and recovery of nitrite accumulation. Results showed that high DO concentration (2-4 mg/L) could damage nitrite accumulation immediately. However, nitrite accumulation ratio (NAR) could be increased from 1.68 ± 1.51 to 35.46 ± 7.86% when increasing the pH values from 7.5 to 8.3 due to the increased free ammonia concentration. Afterwards, stable partial nitrification and high NAR could be recovered when the reactor operated under low DO concentration (0.5-1.0 mg/L). However, it required a long time to recover the partial nitrification of the reactor when the influent COD/N ratios were altered. Fluorescence in situ hybridization analysis implied that ammonium oxidizing bacteria were completely recovered to the dominant nitrifying bacteria in the system. Meanwhile, sludge volumetric index of the reactor gradually decreased from 115.6 to 56.6 mL/g, while the mean diameter of sludge improved from 74.57 to 428.8 ?m by using the strategy of reducing settling time. The obtained results could provide useful information between the operational conditions and the performance of partial nitrification when treating nitrogen-rich industrial wastewater. PMID:23942879

Wei, Dong; Du, Bin; Xue, Xiaodong; Dai, Peng; Zhang, Jian

2014-02-01

351

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

352

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

353

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

354

Comparison of operating strategies for increased biogas production from thin stillage.  

PubMed

The effect of increasing organic loading rate (OLR) and simultaneously decreasing hydraulic retention time (HRT) during anaerobic digestion of sulphur- and nitrogen-rich thin stillage was investigated during operation of continuously stirred tank laboratory reactors at two different temperatures. The operating strategies and substrate were set in order to mimic an existing full-scale commercial biogas plant in Sweden. The reactors were operated for 554-570 days with a substrate mixture of thin stillage and milled grain, resulting in high ammonium concentrations (>4.5gL(-1)). Initially, one reactor was operated at 38°C, as in the full-scale plant, while in the experimental reactor the temperature was raised to 44°C. Both reactors were then subjected to increasing OLR (from 3.2 to 6.0gVSL(-1)d(-1)) and simultaneously decreasing HRT (from 45 to 24 days) to evaluate the effects of these operational strategies on process stability, hydrogen sulphide levels and microbial composition. The results showed that operation at 44°C was the most successful strategy, resulting in up to 22% higher methane yield compared with the mesophilic reactor, despite higher free ammonia concentration. Furthermore, kinetic studies revealed higher biogas production rate at 44°C compared with 38°C, while the level of hydrogen sulphide was not affected. Quantitative PCR analysis of the microbiological population showed that methanogenic archaea and syntrophic acetate-oxidising bacteria had responded to the new process temperature while sulphate-reducing bacteria were only marginally affected by the temperature-change. PMID:24524873

Moestedt, Jan; Nordell, Erik; Schnürer, Anna

2014-04-10

355

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

PubMed

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

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

2012-11-01

356

Performance Assessment of a Fusion Hybrid Reactor Based on the Gasdynamic Mirror  

NASA Astrophysics Data System (ADS)

A preliminary evaluation of the performance of a fusion hybrid reactor whose fusion component is the gasdynamic mirror (GDM) is presented. Since the primary role of the fusion component is to supply high energy neutrons that will induce fission reactions in a blanket surrounding the plasma, it can operate at or below ``break even'' condition. Unlike other fusion devices proposed for this component, the GDM is a linear, cylindrically symmetric device that can operate in steady state making it uniquely suited for this application. We investigate the power producing capability of such a hybrid reactor using the thorium fuel cycle whereby neutrons generated by DT reactions in the GDM impinge on a thorium-232 blanket. These 14.1 MeV neutrons will breed uranium-233 in the blanket and simultaneously burn it to generate power. We treat both the fusion component and the blanket as semi-infinite cylinders so that one-dimensional analysis can be applied. The two relevant equations in this regard are the time evolution of the U-233 density in the blanket, and the neutron one dimensional diffusion equation. We address the steady state operation of this reactor and find that it can produce gigawatts of power per cm, safely since it is ``subcritical,'' and securely since the fuel cycle is proliferation resistant. The approach to steady state will also be presented and analyzed.

Kammash, Terry

2010-11-01

357

Study on the wind\\/biogas integration system for power generation and gas supply  

Microsoft Academic Search

In order to achieve the optimal overall utilization of biogas resources and wind energy, this paper proposes a wind\\/biogas integration system for power generation and gas supply. In the integration system, less wind power is used to heat the biogas pool to raise and keep the fermentation temperature, while most wind power combining with biogas power are directly supplied for

Weidong Gu; Chufu Li; Ming Gu

2009-01-01

358

Biogas production enhancement by Brassica compestries amendment in cattle dung digesters  

Microsoft Academic Search

The present-day energy crisis brings forth to attention biogas as an alternative energy source, i.e. economically feasible and unlimited in potential. Moreover, the economy of biogas plants can be improved by using high biogas potential substrates in combination with cattle dung. One such substrate was identified, having high nitrogen and phosphate content, to amend in cattle dung biogas plants. This

Shanta Satyanarayan; Paresh Murkute; Ramakant

2008-01-01

359

Evaluation of energy efficiency of various biogas production and utilization pathways  

Microsoft Academic Search

The energy efficiency of different biogas systems, including single and co-digestion of multiple feedstock, different biogas utilization pathways, and waste-stream management strategies was evaluated. The input data were derived from assessment of existing biogas systems, present knowledge on anaerobic digestion process management and technologies for biogas system operating conditions in Germany. The energy balance was evaluated as Primary Energy Input

Martina Pöschl; Shane Ward; Philip Owende

2010-01-01

360

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

361

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

362

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

363

Biogas Production from Acid Cheese Whey Using a Two-Stage Digester  

Microsoft Academic Search

A two-stage, no-mix anaerobic digester of 155 l capacity was used to investigate the feasibility of biogas production and the pollution potential reduction of acid cheese whey. The digester was operated at a 15-day hydraulic retention time and three temperatures (19, 25, 35°C). Both the temperature and pH of the whey had significant effects on the performance of the digester.

A. E. GHALY

1989-01-01

364

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

365

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

NASA Astrophysics Data System (ADS)

Sodium environmental effects are key limiting factors in the high temperature structural design of advanced sodium-cooled reactors. A guideline is needed to incorporate environmental effects in the ASME design rules to improve the performance reliability over long operating times. This paper summarizes the influence of sodium exposure on mechanical performance of selected austenitic stainless and ferritic/martensitic steels. Focus is on Type 316SS and mod.9Cr-1Mo. The sodium effects were evaluated by comparing the mechanical properties data in air and sodium. Carburization and decarburization were found to be the key factors that determine the tensile and creep properties of the steels. A beneficial effect of sodium exposure on fatigue life was observed under fully reversed cyclic loading in both austenitic stainless steels and ferritic/martensitic steels. However, when hold time was applied during cyclic loading, the fatigue life was significantly reduced. Based on the mechanical performance of the steels in sodium, consideration of sodium effects in high temperature structural design of advanced fast reactors is discussed.

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

2009-07-01

366

Measurement control design and performance assessment in the Integral Fast Reactor fuel cycle  

SciTech Connect

The Integral Fast Reactor (IFR)--consisting of a metal fueled and liquid metal cooled reactor together with an attendant fuel cycle facility (FCF)--is currently undergoing a phased demonstration of the closed fuel cycle at Argonne National Laboratory. The recycle technology is pyrometalurgical based with incomplete fission product separation and all transuranics following plutonium for recycle. The equipment operates in batch mode at 500 to 1,300 C. The materials are highly radioactive and pyrophoric, thus the FCF requires remote operation. Central to the material control and accounting system for the FCF are the balances for mass measurements. The remote operation of the balances limits direct adjustment. The radiation environment requires that removal and replacement of the balances be minimized. The uniqueness of the facility precludes historical data for design and performance assessment. To assure efficient operation of the facility, the design of the measurement control system has called for procedures which assess the performance of the balances in great detail and will support capabilities for the correction of systematic changes in the performance of the balances through software.

Orechwa, Y.; Bucher, R.G.

1994-08-01

367

Performance of plastic- and sponge-based trickling filters treating effluents from an UASB reactor.  

PubMed

The paper compares the performance of two trickling filters (TFs) filled with plastic- or sponge-based packing media treating the effluent from an upflow anaerobic sludge blanket (UASB) reactor. The UASB reactor was operated with an organic loading rate (OLR) of 1.2 kgCOD m(-3) d(-1), and the OLR applied to the TFs was 0.30-0.65 kgCOD m(-3) d(-1) (COD: chemical oxygen demand). The sponge-based packing medium (Rotosponge) gave substantially better performance for ammonia, total-N, and organic matter removal. The superior TF-Rotosponge performance for NH(4)(+)-N removal (80-95%) can be attributed to its longer biomass and hydraulic retention times (SRT and HRT), as well as enhancements in oxygen mass transfer by dispersion and advection inside the sponges. Nitrogen removals were significant (15 mgN L(-1)) in TF-Rotosponge when the OLRs were close to 0.75 kgCOD m(-3) d(-1), due to denitrification that was related to solids hydrolysis in the sponge interstices. For biochemical oxygen demand removal, higher HRT and SRT were especially important because the UASB removed most of the readily biodegradable organic matter. The new configuration of the sponge-based packing medium called Rotosponge can enhance the feasibility of scaling-up the UASB/TF treatment, including when retrofitting is necessary. PMID:23416595

Almeida, P G S; Marcus, A K; Rittmann, B E; Chernicharo, C A L

2013-01-01

368

Summary of the nuclear design and performance of the Light Water Breeder Reactor (LWBR) (LWBR development program)  

Microsoft Academic Search

This report presents a summary of the nuclear design and expected nuclear performance of the Light Water Breeder Reactor during operation at the Shippingport Atomic Power Station. Performance predictions are presented for core lifetime, breeding margin, power distributions and performance, kinetic and stability parameters, and for core shutdown and reactivity control capability. Also included is a summary of as-built dimensions

Hecker

1979-01-01

369

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

370

Benefits of supplementing an industrial waste anaerobic digester with energy crops for increased biogas production  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer This study demonstrates the feasibility of co-digestion food industrial waste with energy crops. Black-Right-Pointing-Pointer Laboratory batch co-digestion led to improved methane yield and carbon to nitrogen ratio as compared to mono-digestion of industrial waste. Black-Right-Pointing-Pointer Co-digestion was also seen as a means of degrading energy crops with nutrients addition as crops are poor in nutrients. Black-Right-Pointing-Pointer Batch co-digestion methane yields were used to predict co-digestion methane yield in full scale operation. Black-Right-Pointing-Pointer It was concluded that co-digestion led an over all economically viable process and ensured a constant supply of feedstock. - Abstract: Currently, there is increasing competition for waste as feedstock for the growing number of biogas plants. This has led to fluctuation in feedstock supply and biogas plants being operated below maximum capacity. The feasibility of supplementing a protein/lipid-rich industrial waste (pig manure, slaughterhouse waste, food processing and poultry waste) mesophilic anaerobic digester with carbohydrate-rich energy crops (hemp, maize and triticale) was therefore studied in laboratory scale batch and continuous stirred tank reactors (CSTR) with a view to scale-up to a commercial biogas process. Co-digesting industrial waste and crops led to significant improvement in methane yield per ton of feedstock and carbon-to-nitrogen ratio as compared to digestion of the industrial waste alone. Biogas production from crops in combination with industrial waste also avoids the need for micronutrients normally required in crop digestion. The batch co-digestion methane yields were used to predict co-digestion methane yield in full scale operation. This was done based on the ratio of methane yields observed for laboratory batch and CSTR experiments compared to full scale CSTR digestion of industrial waste. The economy of crop-based biogas production is limited under Swedish conditions; therefore, adding crops to existing industrial waste digestion could be a viable alternative to ensure a constant/reliable supply of feedstock to the anaerobic digester.

Nges, Ivo Achu, E-mail: Nges.Ivo_Achu@biotek.lu.se [Department of Biotechnology, Lund University, P.O. Box 124, SE 221 00 Lund (Sweden); Escobar, Federico; Fu Xinmei; Bjoernsson, Lovisa [Department of Biotechnology, Lund University, P.O. Box 124, SE 221 00 Lund (Sweden)

2012-01-15

371

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

NASA Astrophysics Data System (ADS)

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

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

2008-01-01

372

Experience with failed LMR oxide fuel element performance in European fast reactors  

NASA Astrophysics Data System (ADS)

The performance of failed fuel has great significance for the safe and economic operation of LMR's, and considerable experience has accrued from experimental defect pin irradiations and naturally occurring failures in European test and prototype reactors. To data 60 natural fuel element failures have been recorded in PFR, Phénix and KNK II, 41 with exposed fuel and 19 as gas leakers. The various failures occurred during all stages of pin lifetimes, i.e. at the very beginning (0.3 at% burn-up) as well as at medium and at very high burn-up. The present experience extends up to 190 GWd/t and up to 135 dpaNRT. Based on the experience we can state: (i) Even large defects at end-of-life pins resulted in limited fuel loss (ii) No pin-to-pin failure propagation has been observed (iii) The reaction produces formed by the chemical reaction sodium/mixed oxide and the kinetics act beneficially and may protect open cracks. For the European Fast Reactor (EFR) project additional work is being performed, with regard to the EFR requirements of pin design (covering normal operation and incidental events) and the behaviour of failed pins under storage conditions.

Plitz, H.; Crittenden, G. C.; Languille, A.

1993-09-01

373

Computational Neutronics Methods and Transmutation Performance Analyses for Light Water Reactors  

SciTech Connect

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

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

2007-03-01

374

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

375

Quantification of methanogenic heterodisulfide reductase activity in biogas sludge.  

PubMed

Methanogenic archaea are essential for the production of methane in biogas plants. Here we present enzymatic test systems for the analysis of the metabolic activity of methanogens based on the heterodisulfide reductase reaction. The first rapid test shows that heterodisulfide reductase can be detected in 1g of biogas sludge after sonication and centrifugation. The resulting cell lysate used reduced methylviologen for heterodisulfide reduction, a reaction that is specifically catalyzed by methanogenic heterodisulfide reductase. In the second test cell lysate from 60g of biogas sludge was separated by ultracentrifugation. Both, cytoplasmic membrane and cytoplasmic fractions revealed heterodisulfide reductase activity, indicating the presence of hydrogenotrophic and aceticlastic methanogens, respectively. PMID:24721213

Refai, Sarah; Berger, Stefanie; Wassmann, Kati; Deppenmeier, Uwe

2014-06-20

376

Light Water Breeder Reactor fuel rod design and performance characteristics (LWBR Development Program)  

SciTech Connect

Light Water Breeder Reactor (LWBR) fuel rods were designed to provide a reliable fuel system utilizing thorium/uranium-233 mixed-oxide fuel while simultaneously minimizing structural material to enhance fuel breeding. The fuel system was designed to be capable of operating successfully under both load follow and base load conditions. The breeding objective required thin-walled, low hafnium content Zircaloy cladding, tightly spaced fuel rods with a minimum number of support grid levels, and movable fuel rod bundles to supplant control rods. Specific fuel rod design considerations and their effects on performance capability are described. Successful completion of power operations to over 160 percent of design lifetime including over 200 daily load follow cycles has proven the performance capability of the fuel system. 68 refs., 19 figs., 44 tabs.

Campbell, W.R.; Giovengo, J.F.

1987-10-01

377

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

NASA Astrophysics Data System (ADS)

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

Yap?c?, Hüseyin; Übeyli, Mustafa

2006-06-01

378

Performance quality monitoring system for the Daya Bay reactor neutrino experiment  

NASA Astrophysics Data System (ADS)

The Daya Bay Reactor Neutrino Experiment started running on September 23, 2011. The Performance Quality Monitoring system (PQM) has been developed to monitor the detector performance and data quality. The main feature is its ability to efficiently process multi-data-stream from three experimental halls. The PQM processes raw data files from the Daya Bay data acquisition system, generates and publishes histograms via a graphical web interface by executing the user-defined algorithm modules, and saves the histograms for permanent storage. That the whole process takes only around 40 minutes makes it valuable for the shift crew to monitor the running status of all the sub-detectors and the data quality.

Liu, Y. B.; Daya Bay collaboration

2014-06-01

379

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

380

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

PubMed Central

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

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

2009-01-01

381

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

PubMed

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

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

2005-05-01

382

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

PubMed

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

Sabzali, Ahmad; Nikaeen, Mahnaz; Bina, Bijan

2012-01-01

383

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.

2014-01-01

384

Microwave and thermal pretreatment as methods for increasing the biogas potential of secondary sludge from municipal wastewater treatment plants.  

PubMed

In the present study, the sludge was pretreated with microwave irradiation and low-temperature thermal method, both conducted under the same temperature range (30-100°C). Microwave pretreatment was found to be superior over the thermal treatment with respect to sludge solubilization and biogas production. Taking into account the specific energy demand of solubilization, the sludge pre-treated at 60-70°C by microwaves of 900 W was chosen for further experiments in continuous mode, which was more energetically sustainable compared to lower value (700 W) and thermal treatment. Continuous biogas reactor experiments indicated that pre-treated sludge (microwave irradiation: 900 W, temperature: 60-70°C) gave 35% more methane, compared to untreated sludge. Moreover, the results of this study clearly demonstrated that microwave pretreated sludge showed better degree of sanitation. PMID:23500587

Kuglarz, Mariusz; Karakashev, Dimitar; Angelidaki, Irini

2013-04-01

385

High rate performance and characterization of granular methanogenic sludges in upflow anaerobic sludge blanket reactors fed with various defined substrates  

Microsoft Academic Search

High rate granular methanogenic fermentations were performed in one-phase upflow anaerobic sludge blanket (UASB) reactors treating synthetic wastewaters containing starch, sucrose, ethanol, and butyrate plus propionate. All granules formed showed high settling velocities which enabled high cell mass retention and accommodation of high loading rates. The maximum COD removal rates (g COD\\/l-reactor·d) obtained after 500-d operations were 7.6 for starch,

Satoshi Fukuzaki; Naomichi Nishio; Shiro Nagai

1995-01-01

386

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

Microsoft Academic Search

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

J. C. Clayton; B. C. Smith

1991-01-01

387

Development of Predictable Technology for Thermal\\/Hydraulic Performance of Reduced-Moderation Water Reactors (1) - Master Plan -  

Microsoft Academic Search

We start R and D project to develop the predictable technology for thermal-hydraulic performance of Reduced-Moderation Water Reactor (RMWR) in collaboration with power company\\/ reactor vendor\\/ university since 2002. The RMWR can attain the favorable characteristics such as effective utilization of uranium resources, multiple recycling of plutonium, high burn-up and long operation cycle, based on matured BWR technologies. MOX fuel

Akira Ohnuki; Kazuyuki Takase; Masatoshi Kureta; Hiroyuki Yoshida; Hidesada Tamai; Wei Liu; Hajime Akimoto

2004-01-01

388

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

Microsoft Academic Search

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

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

2004-01-01

389

Effect of shock and mixed loading on the performance of SND based sequencing batch reactors (SBR) degrading nitrophenols.  

PubMed

The effect of nitrophenolic shock loads on the performance of three lab scale SBRs was studied using a synthetic feed. Nitrophenols were biotransformed by Simultaneous heterotrophic Nitrification and aerobic Denitrification (SND) using a specially designed single sludge biomass containing Thiosphaera pantotropha. Reactors R1, R2 and R3 were fed with 200mg/L concentration of 4-nitrophenol (4-NP), 2,4-dinitrophenol (2,4-DNP), and 2,4,6-trinitrophenol (2,4,6-TNP) whereas reactor R was used as a background control. Three nitrophenolic shock loadings of 400, 600 and 800 mg/Ld were administrated by increasing the influent nitrophenolic concentration while keeping the hydraulic retention time as 48 h. The shocks were given continuously for a period of 4 days before switching back to normal nitrophenolic loading (200mg/Ld). The reactors were allowed to recover to normal performance level before administrating the next nitrophenolic shock load. The study showed that a nitrophenolic shock load, as high as 600 mg/Ld was completely degraded by the 4-NP & 2,4-DNP bioreactors while almost half degraded by the 2,4,6-TNP bioreactor without affecting the reactor's performance irreversibly. After resuming the normal nitrophenolic loading, it took almost 8-10 days for the reactors to recover from the shock effect. The study was further extended to evaluate the maximum possible mixed nitrophenolic loading (4-NP:2,4-DNP:2,4,6-TNP 1:1:1) to which a reactor (R3) containing 2,4,6-TNP acclimated single sludge biomass can be exposed without hampering the reactor performance irreversibly. The reactor was able to achieve pseudo-steady-state at a mixed nitrophenolic loading of 300 mg/Ld with more than 90% removal of all the three nitrophenols, but could remove half of the mixed nitrophenolic loading of 600 mg/Ld. PMID:22386885

Kulkarni, P M

2012-05-01

390

Performance of a sulfide-oxidizing expanded-bed reactor supplied with dissolved oxygen  

SciTech Connect

The performance of a new sulfide-oxidizing, expanded-bed bioreactor is described. To stimulate the formation of well-settleable sulfur sludge, which comprises active sulfide-oxidizing bacterial biomass and elemental sulfur, the aeration of the liquid phase and the oxidation of sulfide to elemental sulfur are spatially separated. The liquid phase is aerated in a vessel and subsequently recirculated to the sulfide-oxidizing bioreactor. It appeared that, under autotrophic conditions, almost all biomass present in the reactor will be immobilized within the sulfur sludge which consists mainly of elemental sulfur (92%) and biomass (2.5%). The particles formed have a diameter of up to 3 mm and can easily be grinded down. Within time, the sulfur sludge obtained excellent settling properties; e.g., after 50 days of operation, 90% of the sludge settles down at a velocity above 25 m h{sup {minus}1} while 10% of the sludge had a sedimentation velocity higher than 108 m h{sup {minus}1}. Because the biomass is retained in the reactor, higher sulfide loading rates may be applied than to a conventional ``free-cell`` suspension. The maximum sulfide-loading rate reached was 14 g HS{sup {minus}} L{sup {minus}1} d{sup {minus}1}, whereas for a free-cell suspension a maximum loading rate of 6 g HS{sup {minus}} L{sup {minus}1} d{sup {minus}1} was found. At higher loading rates, the upward velocities of the aerated suspension became too high so that sulfur sludge accumulated in the settling zone on top of the reactor.

Janssen, A.J.H.; Ma, S.C.; Lettinga, G. [Agricultural Univ. Wageningen (Netherlands). Dept. of Environmental Technology] [Agricultural Univ. Wageningen (Netherlands). Dept. of Environmental Technology; Lens, P. [University College, Galway (Ireland). Dept. of Microbiology] [University College, Galway (Ireland). Dept. of Microbiology

1997-01-05

391

Performance of permeable media rotating reactors used for pretreatment of wastewaters.  

PubMed

The impact of organic loading rate (OLR) on carbonaceous materials and ammonia removal was assessed in bench scale rotating media biofilm reactors treating real wastewater. Media composition influences biofilm structure and therefore performance. Here, plastic mesh, reticulated coarse foam and fine foam media were operated concurrently at OLRs of 15, 35 and 60 g sCOD m(-2)d(-1) in three bench scale shaft mounted advanced reactor technology (SMART) reactors. The sCOD removal rate increased with loading from 6 to 25 g sCOD m(-2)d(-1) (P < 0.001). At 35 g BOD5m(-2)d(-1), more than double the arbitrary OLR limit of normal nitrifying conditions (15 g BOD5m(-2)d(-1)); the removal efficiency of NH(4)-N was 82 ± 5, 27 ± 19 and 39 ± 8% for the mesh, coarse foam and fine foam media, respectively. Increasing the OLR to 35 gm(-2)d(-1) decreased NH(4)-N removal efficiency to 38 ± 6, 21 ± 4 and 21 ± 6%, respectively. The mesh media achieved the highest stable NH(4)(+)-N removal rate of 6.5 ± 1.6 gm(-2)d(-1) at a sCOD loading of 35 g sCOD m(-2)d(-1). Viable bacterial numbers decreased with increasing OLR from 2 × 10(10)-4 × 10(9) cells per ml of biofilm from the low to high loading, suggesting an accumulation of inert non-viable biomass with higher OLR. Increasing the OLR in permeable media is of practical benefit for high rate carbonaceous materials and ammonia removal in the pretreatment of wastewater. PMID:24804669

Hassard, F; Cartmell, E; Biddle, J; Stephenson, T

2014-01-01

392

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

393

Performance of a palladium membrane reactor using a Ni catalyst for fusion fuel impurities processing  

SciTech Connect

The palladium membrane reactor (PNM) provides a means to recover hydrogen isotopes from impurities expected to be present in fusion reactor exhaust. This recovery is based on reactions such as water-gas shift and steam reforming for which conversion is equilibrium limited. By including a selectively permeable membrane such as Pd/Ag in the catalyst bed, hydrogen isotopes can be removed from the reacting environment, thus promoting the reaction to complete conversion. Such a device has been built and operated at the Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory (LANL). For the reactions listed above, earlier study with this unit has shown that hydrogen single-pass recoveries approaching 100% can be achieved. It was also determined that a nickel catalyst is a feasible choice for use with a PMR appropriate for fusion fuel impurities processing. The purpose of this study was to systematically assess the performance of the PMR using a nickel catalyst over a range of temperatures, feed compositions and flowrates. Reactions which were studied are the water-gas shift reaction and steam reforming.

Willms, R.S.; Wilhelm, R. [Los Alamos National Lab., NM (United States); Okuno, K. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)

1994-07-01

394

Continuous biogas production from fodder beet silage as sole substrate  

Microsoft Academic Search

Abstract Since April 2000 a two-step anaerobic plant with two subsequent 500 m, methane\\/ton fresh fodder beet silage was obtained. Keywords Anaerobic digestion; biogas; biomass; energy plants; fodder beets; renewable energy; silage

P. A. Scherer; S. Dobler; S. Rohardt; R. Loock; B. Büttner; P. Nöldeke; A. Brettschuh

2003-01-01

395

The Small Biogas Plant: Its Construction, Operation and Use.  

National Technical Information Service (NTIS)

This booklet has been prepared in response to the demand for reference material to help interested parties design and operate small biogas plants. It is written in relatively simple language, understandable to people with limited scientific and technical ...

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

1977-01-01

396

Biogas systems in India: is the technology appropriate  

SciTech Connect

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 turned out, the rigidly stratified socioeconomic structure of Indian villages prevented the lower classes from benefiting from the new technology and had the unforeseen effect of ultimately widening the gap between rich and poor. This article looks at how this happened, examines the socioeconomic impact of biogas and discusses the technical improvements needed to make existing biogas plants into a truly appropriate technology in the context of Indian village life. (Refs. 35).

Tucker, J.B.

1982-10-01

397

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

398

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

399

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

400

[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

401

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.

402

Modelling of biogas extraction at an Italian landfill accepting mechanically and biologically treated municipal solid waste.  

PubMed

This paper presents the results of the modelling of the biogas extraction in a full-scale Italian landfill by the USEPA LandGEM model and the Andreottola-Cossu approach. The landfill chosen for this research ('Il Fossetto' plant, Monsummano Terme, Italy) had accepted mixed municipal raw waste for about 15?years. In the year 2003 a mechanical biological treatment (MBT) was implemented and starting from the end of the year 2006, the recirculation in the landfill of the concentrated leachate coming from the internal membrane leachate treatment plant was put into practice. The USEPA LandGEM model and the Andreottola-Cossu approach were chosen since they require only input data routinely acquired during landfill management (waste amount and composition) and allow a simplified calibration, therefore they are potentially useful for practical purposes such as landfill gas management. The results given by the models are compared with measured data and analysed in order to verify the impact of MBT on biogas production; moreover, the possible effects of the recirculation of the concentrated leachate are discussed. The results clearly show how both models can adequately fit measured data even after MBT implementation. Model performance was significantly reduced for the period after the beginning of recirculation of concentrated leachate when the probable inhibition of methane production, due to the competition between methanogens and sulfate-reducing bacteria, significantly influenced the biogas production and composition. PMID:21930528

Calabrò, Paolo S; Orsi, Sirio; Gentili, Emiliano; Carlo, Meoni

2011-12-01

403

Biogas systems in India: is the technology appropriate  

SciTech Connect

Biogas technology is discussed as a possible solution to India's energy and fertilizer problems. The case of biogas systems in India illustrates that science and technology cannot be viewed apart from the social, economic, and political setting in which they are pursued. ''Appropriate'' technological solutions will be met with limited success or may even worsen the existing situation unless complementary structural changes in society are introduced at the same time.

Tucker, J.B.

1982-10-01

404

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

405

Effect of Aeration on the Performance of a Simulated Landfilling Reactor Stabilizing Municipal Solid Wastes  

Microsoft Academic Search

In this study, the effects of intermittent aeration on the anaerobic treatment of domestic solid waste and leachate characteristics were investigated in three simulated landfill anaerobic bioreactors. All of the reactors were operated with leachate recirculation and recirculation rate was 300 mL\\/d. All the reactors were loaded with solid waste having different operational mode. The first reactor was operated with recirculation

Osman Nuri A?da?; Delia Teresa Sponza

2004-01-01

406

Steam generator tube performance. Experience with water-cooled nuclear power reactors during 1986.  

National Technical Information Service (NTIS)

A survey of steam generator operating experience for 1986 has been carried out for 184 pressurized water and pressurized heavy-water reactors, and 1 water-cooled, graphite-moderated reactor. Tubes were plugged at 75 of the reactors (40.5%). In 1986, 3737 ...

O. S. Tatone R. L. Tapping L. Stipan

1992-01-01

407

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

SciTech Connect

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

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

2006-10-27

408

A methodology for performing virtual measurements in a nuclear reactor system  

SciTech Connect

A novel methodology is presented for monitoring nonphysically measurable variables in an experimental nuclear reactor. It is based on the employment of artificial neural networks to generate fuzzy values. Neural networks map spatiotemporal information (in the form of time series) to algebraically defined membership functions. The entire process can be thought of as a virtual measurement. Through such virtual measurements the values of nondirectly monitored parameters with operational significance, e.g., transient-type, valve-position, or performance, can be determined. Generating membership functions is a crucial step in the development and practical utilization of fuzzy reasoning, a computational approach that offers the advantage of describing the state of the system in a condensed, linguistic form, convenient for monitoring, diagnostics, and control algorithms.

Ikonomopoulos, A.; Uhrig, R.E.; Tsoukalas, L.H. (Univ. of Tennessee, Knoxville (United States))

1992-01-01

409

Biogas generation from in-storage psychrophilic anaerobic digestion.  

PubMed

In-storage psychrophilic anaerobic digestion (ISPAD) is a technology allowing livestock producers to operate an anaerobic digester with minimum technological know-how and for the cost of a conventional storage cover. Nevertheless, the system is exposed to ambient temperatures and biogas production is expected to vary with climatic conditions. The objective of the project was therefore to measure ISPAD biogas production during the winter and fall seasons for a region east of Montreal, Canada. A calibrated biogas monitoring system was used to monitor biogas methane and carbon dioxide concentrations inside a two-year-old field installation with a 1000 m3 storage capacity. Despite a leaking pumping hatch, winter 2010 (January to March) methane concentrations varied directly with solar radiation and maximum exterior temperature, rather than with manure temperature at 2.4 and 1.2 m depths which remained relatively constant between 1 and 5 degrees C. During a six-month-period from November 2009 to April 2010, inclusively, the field ISPAD degraded 34% of the manure volatile solids corresponding to an average methane production of 40 m3/d. The ISPAD biogas production could be further increased by improving its air tightness and intrusion and by regularly pumping out the biogas. PMID:23837352

Giard, David; Choiniere, Denis; Cordeau, Sébastien; Barrington, Suzelle

2013-01-01

410

Performance of co-immobilized yeast and glucoamylase in a fluidized bed reactor for fuel ethanol production  

SciTech Connect

The performance of co-immobilized Saccharomyces cerevisiae and glucoamylase was evaluated in a fluidized bed reactor. Soluble starch and yeast extract were used as feed stocks. The biocatalyst performed well and demonstrated no significant loss of activity or physical integrity during 10 weeks of continuous operation. The reactor was easily operated and required no pH control. No operational problems were encountered from bacterial contaminants even though the reactor was operated under non-sterile conditions over the entire course of experiments. Productivities ranged between 25 to 44 g ethanol L{sup -1} h{sup -1}. The experiments demonstrated that ethanol inhibition and bed loading had significant effects on bed performance.

Sun, M.Y.; Bienkowski, P.R.; Davison, B.H. [Oak Ridge National Lab., TN (United States)]|[Univ. of Tennessee, Knoxville, TN (United States); Spurrier, M.A.; Webb, O.F. [Univ. of Tennessee, Knoxville, TN (United States)

1996-07-01

411

Co-digestion of cattle manure with food waste and sludge to increase biogas production  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Small increase in methane production was observed applying sonication pretreatment. Black-Right-Pointing-Pointer Biogas productions between 720 and 1100 mL/Lreactor day were achieved. Black-Right-Pointing-Pointer Volatile solids removal efficiencies ranged between 53% and 60%. Black-Right-Pointing-Pointer Lower methane yields were obtained when operating under thermophilic conditions. Black-Right-Pointing-Pointer Optimum OLR in lab-scale CSTR was 1.2-1.3 g VS/L day (HRT: 20 days). - Abstract: Anaerobic co-digestion strategies are needed to enhance biogas production, especially when treating certain residues such as cattle/pig manure. This paper presents a study of co-digestion of cattle manure with food waste and sewage sludge. With the aim of maximising biogas yields, a series of experiments were carried out under mesophilic and thermophilic conditions using continuously stirred-tank reactors, operating at different hydraulic residence times. Pretreatment with ultrasound was also applied to compare the results with those obtained with non-pretreated waste. Specific methane production decreases when increasing the OLR and decreasing HRT. The maximum value obtained was 603 LCH{sub 4}/kg VS{sub feed} for the co-digestion of a mixture of 70% manure, 20% food waste and 10% sewage sludge (total solid concentration around 4%) at 36 Degree-Sign C, for an OLR of 1.2 g VS/L day. Increasing the OLR to 1.5 g VS/L day led to a decrease of around 20-28% in SMP. Lower methane yields were obtained when operating at 55 Degree-Sign C. The increase in methane production when applying ultrasound to the feed mixtures does not compensate for the energy spent in this pretreatment.

Maranon, E., E-mail: emara@uniovi.es [Department of Chemical Engineering and Environmental Technology, University Institute of Technology of Asturias, Campus of Gijon, University of Oviedo, 33203 Gijon (Spain); Castrillon, L.; Quiroga, G.; Fernandez-Nava, Y. [Department of Chemical Engineering and Environmental Technology, University Institute of Technology of Asturias, Campus of Gijon, University of Oviedo, 33203 Gijon (Spain); Gomez, L.; Garcia, M.M. [Zero Emissions Technology, 41018 Seville (Spain)

2012-10-15

412

Improving the performance of ultrasonic horn reactor for deactivating microorganisms in water  

NASA Astrophysics Data System (ADS)

The research on enhancing the performance of ultrasonic reactor for the purpose of microorganisms' inactivation is still ongoing. In this work, covering the cavitation chamber bottom with a corrugated surface as a source for heterogeneous cavities has been proposed as a simple modification to improve ultrasonic deactivation for ultrasonic horn reactor. Escherichia coli ATCC 25922 was used as a model microorganism in this study. Before using the corrugated surface, the configuration of the cavitation chamber was optimized experimentally in regards to cavitation chamber diameter and the depth of ultrasonic probe tip in the suspension. The optimization of the aforementioned factors was conducted on a basis of using constant suspension volume of 50ml. The depth of the ultrasonic probe tip in the suspension was changed from 2-10mm with a step of 2mm in overall depth of the suspension of 2cm, while the diameter of the chamber was changed using five Pyrex beakers with different diameters. The study was carried out using three level of ultrasonic intensity; low (17.56), intermediate (21.49) and high (24.17) W/cm2. The results of the optimization showed that increasing the diameter of cavitation chamber can decrease the log reduction of E.coli significantly. However, changing the depth of ultrasound probe in the suspension within the studied range was found to have only slight effect on the log reduction of E.coli in the order of approximately 0.5-log10. When using the corrugated surface with optimum chamber design, the results revealed that the corrugated surface can increase the log reduction of E.coli for the applied ultrasonic intensities. This effect was more discernable with low ultrasonic intensity than intermediate and high intensities.

Al-juboori, R. A.; Yusaf, T. F.

2012-09-01

413

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

NASA Technical Reports Server (NTRS)

A water based shielding system is being investigated for use on initial lunar surface power systems. The use of water 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 representative lunar surface reactor shield design is evaluated at various power levels in the Water Shield Testbed (WST) at the NASA Marshall Space Flight Center. The experimental data from the WST is used to anchor a CFD model. Performance of a water shield on the lunar surface is then predicted by CFD models anchored to test data. The accompanying viewgraph presentation includes the following topics: 1) Testbed Configuration; 2) Core Heater Placement and Instrumentation; 3) Thermocouple Placement; 4) Core Thermocouple Placement; 5) Outer Tank Thermocouple Placement; 6) Integrated Testbed; 7) Methodology; 8) Experimental Results: Core Temperatures; 9) Experimental Results; Outer Tank Temperatures; 10) CFD Modeling; 11) CFD Model: Anchored to Experimental Results (1-g); 12) CFD MOdel: Prediction for 1/6-g; and 13) CFD Model: Comparison of 1-g to 1/6-g.

Pearson, J. Boise; Stewart, Eric T.; Reid, Robert S.

2007-01-01

414

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

415

Determination of biogas generation potential as a renewable energy source from supermarket wastes.  

PubMed

Fruit, vegetable, flower waste (FVFW), dairy products waste (DPW), meat waste (MW) and sugar waste (SW) obtained from a supermarket chain were anaerobically digested, in order to recover methane as a source of renewable energy. Batch mesophilic anaerobic reactors were run at total solids (TS) ratios of 5%, 8% and 10%. The highest methane yield of 0.44 L CH4/g VS(added) was obtained from anaerobic digestion of wastes (FVFW+DPW+MW+SW) at 10% TS, with 66.4% of methane (CH4) composition in biogas. Anaerobic digestion of mixed wastes at 5% and 8% TS provided slightly lower methane yields of 0.41 and 0.40 L CH4/g VS(added), respectively. When the wastes were digested alone without co-substrate addition, the highest methane yield of 0.40 L CH4/g VS(added) was obtained from FVFW at 5% TS. Generally, although the volatile solids (VS) conversion percentages seemed low during the experiments, higher methane yields could be obtained from anaerobic digestion of supermarket wastes. A suitable carbon/nitrogen (C/N) ratio, proper adjustment of the buffering capacity and the addition of essential trace nutrients (such as Ni) could improve VS conversion and biogas production yields significantly. PMID:24120116

Alkanok, Gizem; Demirel, Burak; Onay, Turgut T

2014-01-01

416

The performance of immobilized glucose isomerase supported by shrimp chitin in various types of reactors.  

PubMed

Five different types of reactors were employed for glucose isomerization using shrimp shell as the support on which to immobilize the glucose isomerase. The Michaelis-Menten constants and effective diffusivity of glucose in the immobilized enzyme bed were experimentally determined and used in a theoretical analysis of the radial-flow reactor. The fractional conversions of the radial-flow, fluidizedbed, and packed-bed reactors with the same -residence time were found experimentally to be almost the same. This result reveals that the use of radial-flow and fluidized-bed reactors for this immobilized enzyme system is highly feasible. PMID:18548689

Chen, F S; Weng, H S; Lai, C L

1983-03-01

417

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

418

Stability of test environments for performance evaluation of materials for the modular high-temperature gas-cooled reactor.  

National Technical Information Service (NTIS)

Stability of the primary helium-based coolant test gas for use in performance tests of materials for the Modular High-Temperature Gas-Cooled Reactor (MHTGR) was determined. Results of tests of the initial gas chemistry from General Atomics (GA) at elevate...

G. L. Edgemon D. F. Wilson G. E. C. Bell

1993-01-01

419

Enzyme research and applications in biotechnological intensification of biogas production.  

PubMed

Biogas technology provides an alternative source of energy to fossil fuels in many parts of the world. Using local resources such as agricultural crop remains, municipal solid wastes, market wastes and animal waste, energy (biogas), and manure are derived by anaerobic digestion. The hydrolysis process, where the complex insoluble organic materials are hydrolysed by extracellular enzymes, is a rate-limiting step for anaerobic digestion of high-solid organic solid wastes. Biomass pretreatment and hydrolysis are areas in need of drastic improvement for economic production of biogas from complex organic matter such as lignocellulosic material and sewage sludge. Despite development of pretreatment techniques, sugar release from complex biomass still remains an expensive and slow step, perhaps the most critical in the overall process. This paper gives an updated review of the biotechnological advances to improve biogas production by microbial enzymatic hydrolysis of different complex organic matter for converting them into fermentable structures. A number of authors have reported significant improvement in biogas production when crude and commercial enzymes are used in the pretreatment of complex organic matter. There have been studies on the improvement of biogas production from lignocellulolytic materials, one of the largest and renewable sources of energy on earth, after pretreatment with cellulases and cellulase-producing microorganisms. Lipids (characterised as oil, grease, fat, and free long chain fatty acids, LCFA) are a major organic compound in wastewater generated from the food processing industries and have been considered very difficult to convert into biogas. Improved methane yield has been reported in the literature when these lipid-rich wastewaters are pretreated with lipases and lipase-producing microorganisms. The enzymatic treatment of mixed sludge by added enzymes prior to anaerobic digestion has been shown to result in improved degradation of the sludge and an increase in methane production. Strategies for enzyme dosing to enhance anaerobic digestion of the different complex organic rich materials have been investigated. This review also highlights the various challenges and opportunities that exist to improve enzymatic hydrolysis of complex organic matter for biogas production. The arguments in favor of enzymes to pretreat complex biomass are compelling. The high cost of commercial enzyme production, however, still limits application of enzymatic hydrolysis in full-scale biogas production plants, although production of low-cost enzymes and genetic engineering are addressing this issue. PMID:21851320

Parawira, Wilson

2012-06-01

420

Substrate inhibition and control for high rate biogas production  

SciTech Connect

This research addresses a critical aspect of the technical feasibility of biogas recovery with poultry manure using anaerobic digestion, namely, inhibition and toxicity factors limiting methane generation under high rate conditions. The research was designed to identify the limiting factors and to examine alternative pretreatment and in situ control methods for the anaerobic digestion of poultry manure as an energy producing system. Biogas production was indicated by the daily gas volume produced per unit digester capacity. Enhanced biogas generation from the anaerobic digester systems using poultry manure was studied in laboratory- and pilot-scale digester operations. It was found that ammonia nitrogen concentration above 4000 mg/l was inhibitory to biogas production. Pretreatment of the manure by elutriation was effective for decreasing inhibitory/toxic conditions. Increased gas production resulted without an indication of serious inhibition by increased volatile acids, indicating a limitation of available carbon sources. For poultry manure digestion, the optimum pH range was 7.1 to 7.6. Annual costs for pretreatment/biogas systems for 10,000, 30,000 and 50,000 birds were estimated and compared with annual surplus energy produced. The economic break-even point was achieved in digesters for greater than 30,000 birds. Capital cost of the digester system was estimated to be $18,300 with annual costs around $4000. It is anticipated that the digester system could be economically applied to smaller farms as energy costs increase.

Shin, H.S.

1982-01-01

421

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

422

[Application of biogas fermentation residue in Ziziphus jujuba cultivation].  

PubMed

With field experiment, this paper studied the effects of applying biogas fermentation residue (dregs and slurry) on jujube growth, its fruit quality, and soil fertility. The results showed that biogas fermentation residue could enhance the disease-resistance of jujube plant and its fruit, and improve fruit quality and soil fertility. Compared with applying chemical fertilizers (the control), biogas fermentation residue increased the contents of jujube fruit coarse fiber, vitamin C, amino acids, Fe and P by 27.69%, 24.85%, 19.81%, 10.89% and 5.26%, and of soil organic carbon, total nitrogen and mineral nitrogen by 42.65%, 37.61% and 35.26%, respectively. The soil pH was decreased from 8.75 to 8.21. Biogas fermentation residue could also increase the amount of soil microorganisms. The microbial biomass-C and biomass-N were 59.44% and 56.06% higher than the control, respectively. It was suggested that biogas fermentation residue application could bring better economic and environmental benefits for Z. jujuba cultivation, and also, provide a new approach for no-pollution production of jujube. PMID:16706067

Yu, Fangbo; Guan, Xiaojin; Zhao, Ziru; Zhang, Mingxing; Guo, Peng; Pan, Jijie; Li, Shunpeng

2006-02-01

423

Integrated removal of nitrate and carbon in an upflow anaerobic sludge blanket (UASB) reactor: Operating performance  

Microsoft Academic Search

Denitrification and methanogenesis of a synthetic wastewater containing volatile fatty acids and nitrate were obtained in a single-stage process using an upflow anaerobic sludge blanket (UASB) reactor. The reactor was initially inoculated with methanogenic granular sludge and was gradually adapted to nitrate by increasing the nitrate concentration in the influent. Excess carbon not utilized for denitrification was converted to methane.

Hanne Vang Hendriksen; Birgitte Kiær Ahring

1996-01-01

424

Physics experiments and lifetime performance of the light water breeder reactor  

Microsoft Academic Search

The authors discuss the light water breeder reactor (LWBR) operated at the Shippingport Atomic Power Station from 1977 to 1982, serving the electric power grid for the Greater Pittsburgh area. The LWBR was a pressurized water reactor (PWR) with several unique features. It was designed and proved to be a breeder with an end-of-life fissile fuel content -- 1.3% greater

L. B. Freeman; B. R. Beaudoin; R. A. Frederickson; G. L. Hartfield; H. C. Hecker; S. Milani; W. K. Sarber; W. C. Schick

1989-01-01

425

Performance characteristics of the annular core research reactor fuel motion detection system  

Microsoft Academic Search

Recent proof tests have shown that the annular core research reactor (ACRR) fuel motion detection system has reached its design goals of providing high temporal and spatial resolution pictures of fuel distributions in the ACRR. The coded aperture imaging system (CAIS) images the fuel by monitoring the fission gamma rays from the fuel that pass through collimators in the reactor

J. G. Kelly; K. T. Stalker

1983-01-01

426

Operational performance of the three bean salad control algorithm on the ACRR (Annular Core Research Reactor)  

Microsoft Academic Search

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.,

R. M. Ball; J. J. Madaras; F. R. Jr. Trowbridge; D. G. Talley; E. J. Jr. Parma

1991-01-01

427

Operation conditions affecting the performance of airlift reactors for immobilized enzyme reactions  

Microsoft Academic Search

The applicability of concentric airlift reactors for immobilized enzyme reaction has been studied. Because of simple mechanical structure, good mixing, relatively low shear stress, and lower power consumption, the airlift reactor is apealing for immobilized enzyme reaction. The operation conditions can be optimized by manipulating aeration rate, top clearance space, and solid content.

Chun-Min Chang; Wen Jang Lu; Ku Song Own; Shyh-Jye Hwang

1993-01-01

428

Effect of aeration on the performance of a simulated landfilling reactor stabilizing municipal solid wastes.  

PubMed

In this study, the effects of intermittent aeration on the anaerobic treatment of domestic solid waste and leachate characteristics were investigated in three simulated landfill anaerobic bioreactors. All of the reactors were operated with leachate recirculation and recirculation rate was 300 mL/d. All the reactors were loaded with solid waste having different operational mode. The first reactor was operated with recirculation (control-no aeration). The second reactor was aerated three days in a week during 1 h (Run 1) and the last reactor was aerated one day in a week during 1 h (Run 2). pH, chemical oxygen demand (COD), volatile fatty acids (VFA), ammonium nitrogen (NH4-N), nitrate nitrogen (NO3-N) concentrations, total, and methane gas productions in the leachate samples were regularly monitored. 96, 85, and 97% COD and 86, 77, and 93% VFA removals were obtained, in the leachate samples of the control, R1 and R2 reactors, respectively, after 79 days of anaerobic incubation. The TN, TP and NH4-N concentrations in MSW reduced to 4300, 1100, and 160 mg/g from 11,100, 2450, and 630 mg/g in R1 reactor by day 79. The values of pH were 6.98, 6.76, and 7.98, respectively, after anaerobic incubation, respectively in the aforementioned reactors. It was observed that the aeration decreased the methane percentage and the quantity in the simulated bioreactor. The maximum cumulative methane gas production was recorded as 11.2, 0.9, and 3.6 L in control, R1 and R2 reactors, respectively, at the end of 79 days. A BOD5/COD ratio of 0.23 achieved in the R2 reactor indicated the better MSW stabilization resulting in a high rate than that of R1 and control reactors. It was observed that the aerated reactor one day in a week during one hour (R2) reduced the COD and VFA concentrations in leachate samples. The aerated reactor three days in a week during 1 h (R1) reduced the waste quantity, the organic content of the solid waste. The final leachate quantities of aerated runs were lower than that of control reactor operated under strictly anaerobic conditions. PMID:15533016

A?da?, Osman Nuri; Sponza, Delia Teresa

2004-01-01

429

Electron versus proton accelerator driven sub-critical system performance using TRIGA reactors at power  

SciTech Connect

This paper provides a comparison of the performance of an electron accelerator-driven experiment, under discussion within the Reactor Accelerator Coupling Experiments (RACE) Project, being conducted within the U.S. Dept. of Energy's Advanced Fuel Cycle Initiative (AFCI), and of the proton-driven experiment TRADE (TRIGA Accelerator Driven Experiment) originally planned at ENEA-Casaccia in Italy. Both experiments foresee the coupling to sub-critical TRIGA core configurations, and are aimed to investigate the relevant kinetic and dynamic accelerator-driven systems (ADS) core behavior characteristics in the presence of thermal reactivity feedback effects. TRADE was based on the coupling of an upgraded proton cyclotron, producing neutrons via spallation reactions on a tantalum (Ta) target, with the core driven at a maximum power around 200 kW. RACE is based on the coupling of an Electron Linac accelerator, producing neutrons via photoneutron reactions on a tungsten-copper (W-Cu) or uranium (U) target, with the core driven at a maximum power around 50 kW. The paper is focused on analysis of expected dynamic power response of the RACE core following reactivity and/or source transients. TRADE and RACE target-core power coupling coefficients are compared and discussed. (authors)

Carta, M.; Burgio, N.; D'Angelo, A.; Santagata, A. [ENEA, C.R. Casaccia, via Anguillarese, 301, 00060, S. Maria di Galeria, Rome (Italy); Petrovich, C. [ENEA, C.R.E. Clementel, via M. M. Sole, 4, 40129, Bologna (Italy); Schikorr, M. [Forschungszentrum Karlsruhe FZK, Postfach 3640, D-76021 Karlsruhe (Germany); Beller, D. [Univ. of Nevada, 4505 Maryland Parkway, Las Vegas, NV 89154-4027 (United States); Felice, L. S. [CEA, CEN Cadarache, 13108 St-Paul-lez-Durance (France); Imel, G. [Argonne National Laboratory, 9700 South Cass Ave, Argonne, IL 60439 (United States); Salvatores, M. [Forschungszentrum Karlsruhe FZK, Postfach 3640, D-76021 Karlsruhe (Germany); CEA, CEN Cadarache, 13108 St-Paul-lez-Durance (France)

2006-07-01

430

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

431

Performance evaluation for carbonation of steel-making slags in a slurry reactor.  

PubMed

CO(2) sequestration by the aqueous carbonation of steel-making slag under various operational conditions was investigated in this study. The effects of the operational conditions, including type of steel-making slag, reaction time, reaction temperature, and CO(2) flow rate, on the performance of the carbonation process were evaluated. The results indicated that the BOF slag had the highest carbonation conversion, approximately 72%, at a reaction time of 1h, an operating pressure of 101 kPa and a temperature of 60°C due to its higher BET surface area of BOF slag compared to UF, FA, and BHC slags. The major factors affecting the carbonation conversion are reaction time and temperature. The reaction kinetics of the carbonation conversion can be expressed by the shrinking-core model. The measurements of the carbonated material by the SEM and XRD instruments provide evidence indicating the suitability of using the shrinking-core model in this investigation. Comparison of the results with other studies suggests that aqueous carbonation by slurry reactor is viable due to its higher mass transfer rate. PMID:21168964

Chang, E-E; Chen, Chung-Hua; Chen, Yi-Hung; Pan, Shu-Yuan; Chiang, Pen-Chi

2011-02-15

432

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

433

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

434

Potential errors in the quantitative evaluation of biogas production in anaerobic digestion processes  

Microsoft Academic Search

Errors that are commonly made in the quantification of biogas from anaerobic digestion experiments were investigated.For liquid displacement gasometers where a barrier solution separates the biogas and the atmosphere, inaccuracy due to gas diffusion was examined experimentally. Acidified saturated saline solution was the most suitable barrier solution, as biogas characteristics changed least with time. Using acidified or tap water caused

Mark Walker; Yue Zhang; Sonia Heaven; Charles Banks

2009-01-01

435

Dutch gas distribution grid goes green: decision support tool for local biogas utilization  

Microsoft Academic Search

A Decision Support Tool (DST) has been developed that will aid Distribution Service Operators (DSOs) in their decision making process on which investments to make in the gas distribution grid in order to facilitate the use of biogas. The DST considers both the conversion of biogas to electricity as well as upgrading the biogas to green gas and consequently injecting

T. D. Weidenaar

2011-01-01

436

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

437

Biogas production in agriculture: safety guidelines, cofermentation and emissions from combined heat and power couplings  

Microsoft Academic Search

Biogas production is an effective means for improving the efficiency of slurry utilisation. It has several positive effects : energy gaining from a renewable source, reducing of methane emissions during slurry storage, improving the nitrogen availability after spreading of the slurry. The number of agricultural biogas plants increases continuously. There is a shortage of documets for constructing biogas plants and

Amon Thomas

438

Reactor performance of a 750 m(3) anaerobic digestion plant: Varied substrate input conditions impacting methanogenic community.  

PubMed

A 750 m(3) anaerobic digester was studied over a half year period including a shift from good reactor performance to a reduced one. Various abiotic parameters like volatile fatty acids (VFA) (formic-, acetic-, propionic-, (iso-)butyric-, (iso-)valeric-, lactic acid), total C, total N, NH4 -N, and total proteins, as well as the organic matter content and dry mass were determined. In addition several process parameters such as temperature, pH, retention time and input of substrate and the concentrations of CH4, H2, CO2 and H2S within the reactor were monitored continuously. The present study aimed at the investigation of the abundance of acetogens and total cell numbers and the microbial methanogenic community as derived from PCR-dHPLC analysis in order to put it into context with the determined abiotic parameters. An influence of substrate quantity on the efficiency of the anaerobic digestion process was found as well as a shift from a hydrogenotrophic in times of good reactor performance towards an acetoclastic dominated methanogenic community in times of reduced reactor performance. After the change in substrate conditions it took the methano-archaeal community about 5-6 weeks to be affected but then changes occurred quickly. PMID:24727280

Wagner, Andreas Otto; Malin, Cornelia; Lins, Philipp; Gstraunthaler, Gudrun; Illmer, Paul

2014-10-01

439

Effects of organic loading rate and effluent recirculation on the performance of two-stage anaerobic digestion of vegetable waste.  

PubMed

The effects of organic loading rates (OLR) and effluent recirculation on dynamics of acidogenic and methanogenic processes in two-stage anaerobic digestion of vegetable waste were investigated. Two systems were performed at OLRs of 1.3, 1.7, 2.1 and 2.6 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

440

Effect of phenol on the nitrogen removal performance and microbial community structure and composition of an anammox reactor.  

PubMed

The effects of phenol on the nitrogen removal performance of a sequencing batch reactor (SBR) with anammox activity and on the microbial community within the reactor were evaluated. A phenol concentration of 300mgL(-1) reduced the ammonium-nitrogen removal efficiency of the SBR from 96.5% to 47%. The addition of phenol changed the microbial community structure and composition considerably, as shown by denaturing gradient gel electrophoresis and 454 pyrosequencing of 16S rRNA genes. Some phyla, such as Proteobacteria, Verrucomicrobia, and Firmicutes, increased in abundance, whereas others, such as Acidobacteria, Chloroflexi, Planctomycetes, GN04, WS3, and NKB19, decreased. The diversity of the anammox bacteria was also affected by phenol: sequences related to Candidatus Brocadia fulgida were no longer detected, whereas sequences related to Ca. Brocadia sp. 40 and Ca. Jettenia asiatica persisted. These results indicate that phenol adversely affects anammox metabolism and changes the bacterial community within the anammox reactor. PMID:24907569

Pereira, Alyne Duarte; Leal, Cíntia Dutra; Dias, Marcela França; Etchebehere, Claudia; Chernicharo, Carlos Augusto L; de Araújo, Juliana Calabria

2014-08-01

441

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.

442

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

443

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

PubMed Central

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.

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

2014-01-01

444

Performance and kinetic process analysis of an Anammox reactor in view of application for landfill leachate treatment.  

PubMed

Anammox has shown its promise and low cost for removing nitrogen from high strength wastewater such as landfill leachate. A reactor was inoculated with nitrification-denitrification sludge originating from a landfill leachate treating waste water treatment plant. During the operation, the sludge gradually converted into red Anammox granular sludge with high and stable Anammox activity. At a maximal nitrogen loading rate of 0.6 g N l(-1) d(-1), the reactor presented ammonium and nitrite removal efficiencies of above 90%. In addition, a modified Stover-Kincannon model was applied to simulate and assess the performance of the Anammox reactor. The Stover-Kincannon model was appropriate for the description of the nitrogen removal in the reactor with the high regression coefficient values (R2 = 0.946) and low Theil's inequality coefficient (TIC) values (TIC < 0.3). The model results showed that the maximal N loading rate of the reactor should be 3.69 g N l(-1) d(-). PMID:24701919

Gao, Junling; Chys, Michael; Audenaert, Wim; He, Yanling; Van Hulle, Stijn W H

2014-01-01

445

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

446

Method and apparatus for enhancing reactor air-cooling system performance  

DOEpatents

An enhanced decay heat removal system 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.

Hunsbedt, Anstein (Los Gatos, CA)

1996-01-01

447

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

448

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

449

[Comparison between porous polymer carrier and activated carbon carrier used for treating organic wastewater in anaerobic fluidized-bed reactor].  

PubMed

A comparative performance between porous polymer carriers (HP) and granular activated carbon carriers (GAC) in anaerobic fluidied-bed reactors was undertaken to evaluate their characters. The results showed that the COD removal and the biogas volume yield rate were 84% and 16.5 m3/(m3.d) respectively when HP was used as carrier to treat synthetic wastewater, at the top COD organic load rate of 65.5 kg/(m3.d), however those were 74.2% and 14.5% respectively for GAC carrier at the top load rate of 63.25 kg/(m3.d). The COD removal and biogas volume yield rate were 64.7%-54.5% and 1.89-2.7 m3/(m3.d) respectively when HP was used as carriers to treat straw pulping wastewater, at the load rate of 14.5-36.15 kg/(m3.d), and those were 61.0%-52.1% and 0.73-2.0 m3/(m3.d) respectively for GAC carriers at the load rate 9.16-19.06 kg/(m3.d). The study revealed that the HP carriers reactor is more efficient than the GAC carriers reactor in microbial immobilization and the wastewater treatment. PMID:11382041

Yang, P; Fang, Z; Shi, Y

2001-01-01

450

THERMAL PERFORMANCE OF A FAST NEUTRON TEST CONCEPT FOR THE ADVANCED TEST REACTOR  

SciTech Connect

Since 1967, the Advanced Test Reactor (ATR) located at Idaho National Laboratory (INL) has provided state-of-the-art experimental irradiation testing capability. A unique design is investigated herein for the purpose of providing a fast neutron flux test capability in the ATR. This new test capability could be brought on line in approximately 5 or 6 years, much sooner than a new test reactor could be built, to provide an interim fast-flux test capability in the timeframe before a fast-flux research reactor could be built. The proposed cost for this system is approximately $63M, much less than the cost of a new fast-flux test reactor. A concept has been developed to filter out a large portion of the thermal flux component by using a thermally conductive neutron absorber block. The objective of this study is to determine the feasibility of this experiment cooling concept.

Donna Post Guillen

2008-06-01

451

In-reactor performance of LWR-type tritium target rods  

SciTech Connect

Pacific Northwest Laboratory has conducted several 1-yr irradiation tests of light water reactor-type tritium target rods. These tests have been sponsored by the U.S. Department of Energy's Office of New Production Reactors. The first test, designated water capsule-1 (WC-1), was conducted in the Advanced Test Reactor (ATR) at the Idaho National Engineering Laboratory from November 1989 to December 1990. The test vehicle contained a single 4-ft target rod within a pressurized water capsule. The capsule maintained the rod at pressurized water reactor (PWR)-type water temperature and pressure conditions. Posttest nondestructive examinations of the WC-1 rod involved visual examinations, dimensional checks, gamma scanning, and neutron radiography. The results indicate that the rod maintained the integrity of its pressure seal and was otherwise unaltered both mechanically and dimensionally by its irradiation and posttest handling.

Lanning, D.D. (Battelle-Pacific Northwest Lab., Richland, WA (United States)); Paxton, M.M. (Westinghouse Hanford Co., Richland, WA (United States)); Crumbaugh, L. (Idaho National Engineering Lab., Idaho Falls (United States))

1992-01-01

452

AN INVESTIGATION OF THE EFFECT OF BUBBLE DIAMETER ON THE PERFORMANCE OF GAS-SOLID FLUIDIZED BED REACTOR AND TWO-PHASE MODELING OF BUBBLING FLUIDIZED BED REACTOR IN MELAMINE PRODUCTION  

Microsoft Academic Search

Bubble diameter is an important parameter in the modeling of gas-solid fluidized bed reactor and plays an important role in the performance of the fluidized bed reactor. Determination of the actual bubble diameter in the fluidized bed is very important. Bubble diameter starts at the initial bubble diameter ( 0

Amir Farshi; Houman Javaherizadeh; M. A. Hamzavi

453

Changes in process performance and microbial characteristics of retained sludge during low-temperature operation of an EGSB reactor.  

PubMed

A lab-scale expanded granular sludge bed (EGSB) reactor was seeded with granular sludge and operated to investigate the influence of temperature decrease on both process performance and the microbial community structure of the granular sludge. Synthetic wastewater containing sucrose and volatile fatty acids was used as feed. The EGSB reactor was brought online at a starting temperature of 15 degrees C and was reduced stepwise to a final temperature of 5 degrees C. The reactor exhibited sufficient COD removal efficiency between 10 degrees C and 15 degrees C. However at 5 degrees C serious deterioration of process performance was observed. The methane-producing activity of the retained sludge increased when it was compared to the activity of the seed sludge (day 0) during 10 degrees C to 15 degrees C operation. When hydrogen fed, sludge showed much higher methanogenic activity as compared with seed sludge activity at test temperatures of 15 degrees C and 20 degrees C on day 196 of reactor operation. At this time, proliferation of the genus Methanospirillum in the retained sludge was observed and a decrease in Methanobacterium species was also measured. Throughout the experiment, the genus Methanosaeta was detected in abundance and the community structure of the Domain Bacteria was stably maintained. The sugar-degrading acid-forming bacteria, Lactococcus and Anaerovibrio were detected in the retained sludge throughout the experiment as well and the propionate-degrading acetogen Syntrophobacter fumaroxidans was also detected, although its population size decreased at 5 degrees C. PMID:18988102

Yoochatchaval, Wilasinee; Tsushima, Ikuo; Ohashi, Akiyoshi; Harada, Hideki; Yamaguchi, Takashi; Araki, Nobuo; Syutsubo, Kazuaki

2008-12-01

454

77 FR 29167 - Effluent Limitations Guidelines and New Source Performance Standards for the Airport Deicing...  

Federal Register 2010, 2011, 2012, 2013

...of the gas in onsite boilers in order to maintain reactor temperature. The remainder of gas can be either combusted in a microturbine for electricity generation or flared. Regardless of the combustion technology, nearly all biogas generated by AFBs is...

2012-05-16

455