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1.
Borole AP Klasson KT Ridenour W Holland J Karim K Al-Dahhan MH 《Applied biochemistry and biotechnology》2006,131(1-3):887-896
Manure waste from dairy farms has been used for methane production for decades, however, problems such as digester failure are routine. The problem has been investigated in small scale (1-2 L) digesters in the laboratory; however, very little scale-up to intermediate scales are available. We report production of methane in a 100-L digester and the results of an investigation into the effect of partial mixing induced by gas upflow/recirculation in the digester. The digester was operated for a period of about 70 d (with 16-d hydraulic retention time) with and without the mixing induced by gas recirculation through an internal draft tube. The results show a clear effect of mixing on digester operation. Without any mixing, the digester performance deteriorated within 30-50 d, whereas with mixing continuous production of methane was observed. This study demonstrates the importance of mixing and its critical role in design of large scale anaerobic digesters. 相似文献
2.
Karim K Klasson KT Drescher SR Ridenour W Borole AP Al-Dahhan MH 《Applied biochemistry and biotechnology》2007,142(3):231-242
Anaerobic digestion kinetics study of cow manure was performed at 35°C in bench-scale gas-lift digesters (3.78 l working volume)
at eight different volatile solids (VS) loading rates in the range of 1.11–5.87 g l−1 day−1. The digesters produced methane at the rates of 0.44–1.18 l l−1 day−1, and the methane content of the biogas was found to increase with longer hydraulic retention time (HRT). Based on the experimental
observations, the ultimate methane yield and the specific methane productivity were estimated to be 0.42 l CH4 (g VS loaded)–1 and 0.45 l CH4 (g VS consumed)–1, respectively. Total and dissolved chemical oxygen demand (COD) consumptions were calculated to be 59–17% and 78–43% at 24.4–4.6 days
HRTs, respectively. Maximum concentration of volatile fatty acids in the effluent was observed as 0.7 g l–1 at 4.6 days HRT, while it was below detection limit at HRTs longer than 11 days. The observed methane production rate did
not compare well with the predictions of Chen and Hashimoto’s [1] and Hill’s [2] models using their recommended kinetic parameters. However, under the studied experimental conditions, the predictions of
Chen and Hashimoto’s [1] model compared better to the observed data than that of Hill’s [2] model. The nonlinear regression analysis of the experimental data was performed using a derived methane production rate
model, for a completely mixed anaerobic digester, involving Contois kinetics [3] with endogenous decay. The best fit values for the maximum specific growth rate (μ
m) and dimensionless kinetic parameter (K) were estimated as 0.43 day–1 and 0.89, respectively. The experimental data were found to be within 95% confidence interval of the prediction of the derived
methane production rate model with the sum of residual squared error as 0.02. 相似文献
3.
In order to develop a suitable reactor for the biomethanation of high-strength salty cheese whey, the performance of anaerobic
upflow fixed-film reactors packed with different support materials, such as charcoal, gravel, brick pieces, pumicestones,
and PVC pieces, has been studied. The charcoal-bedded reactor gave the best performance, with the maximum gas production (3.3
L/L digester/d) and an enriched methane content (69% CH4). Temperature and hydraulic retention time were optimized, with the ultimate aim of improving biomethanation. Maximum gas
production (3.3 L/L digester/d) was achieved at a hydraulic retention time of 2 d at 40°C. 相似文献
4.
This paper describes the results of a study aimed at improving the efficiency of anaerobic digestion of salty cheese whey
in combination with poultry waste or cattle dung. Best results were obtained when salty cheese whey was mixed with poultry
waste in the ratio of 7:3, or cattle dung in the ratio of 1:1, both on dry weight basis giving maximum gas production of 1.2
L/L of digester/d with enriched methane content of 64% and 1.3 L/L of digester/d having methane content of 63% respectively.
Various conditions such as temperature and retention time have been optimized for maximum process performance. 相似文献
5.
Chirag Patel Vishwanada Sastry Datta Madamwar 《Applied biochemistry and biotechnology》1996,56(1):89-94
To obtain enriched methane content and improve the anaerobic digestion of a mixture of cattle dung, poultry waste, and cheese
whey, the effect of various doses of Tegoprens: T-3012, T-3022, T-5842, T-5843, T-5851, T-5852 has been studied, in bench-scale
digesters. Among them, Tegoprens 3022 showed more than a 45% increase in gas production with higher methane content. 相似文献
6.
Basic phenomena of the reduction of carbon dioxide to reusable organic materials including methane and methanol were investigated
by using a radio frequency impulse discharge in a low gas pressure range without catalysis. The discharge took place under
different discharge parameters such as voltage, gas flow rate, gas-mixing ratio, and gas residence time, where the carbon
dioxide was mixed with hydrogen at total gas pressure of 1–10 Torr. Organic materials such as methane and methanol were observed.
Carbon monoxide was a major product from carbon dioxide. Methane was the dominant organic species produced by the discharge.
The concentration of methane increased with discharge voltage, and its volume fraction attained 10–20% of the products containing
carbon that came from carbon dioxide. This fraction was also dependent on the mixing ratio of carbon dioxide and hydrogen.
We also observed the formation of methanol, though its fraction was low, a few %, compared with methane. 相似文献
7.
Ramona Pristavita Norma-Yadira Mendoza-Gonzalez Jean-Luc Meunier Dimitrios Berk 《Plasma Chemistry and Plasma Processing》2010,30(2):267-279
Carbon black (CB) nanopowders were obtained by plasma decomposition of methane at various flow rates using inductively coupled
thermal plasma torch system of 35 kW. Nitrogen was also introduced in some experiments along with the methane. Using a cylindrical
shape reactor the obtained powders were composed mainly of spherical particles, non-uniform in terms of particles size with
diameters between 30 and 150 nm. The shape and size of this reactor resulted in the presence of recirculation areas enabling
the formation of large CB particles and other secondary volatile compounds. Changing the reactor to a conical geometry resulted
in the production of CB powders showing a crystalline and flake-like morphology made of sheets having 6–16 graphitic planes.
The conical shape avoids the presence of recirculation areas and promotes the formation of a uniform powder morphology throughout
the reactor. 相似文献
8.
Novel, laboratory-scale, high-solids reactors operated under mesophilic conditions were used to study the anaerobic fermentation
of processed municipal solid waste (MSW) to methane. Product gas rate data were determined for organic loading rates ranging
from 2.99–18.46 g of volatile solids (VS) per liter (L) per day (d). The data represent the anaerobic fermentation at high-solids
levels within the reactor of 21–32%, while feeding a refuse-derived fuel (RDF)/MSW feedstock supplemented with a vitamin/mineral/nutrient
solution. The average biogas yield was 0.59 L biogas/g VS added to the reactor system/d. The average methane composition of
the biogas produced was 57.2%. The data indicate a linear relationship of increasing total biogas production with increasing
organic loading rate to the process. The maximum organic loading rate obtainable with high-solids anaerobic digestion is in
the range of 18–20 g VS/L·d to obtain 80% or greater bioconversion for the RDF/MSW feedstock. This loading rate is approximately
four to six times greater than that which can be obtained with comparable low-solids anaerobic bioreactor technology. 相似文献
9.
Biogas Production from Anaerobic Co-digestion of Food Waste with Dairy Manure in a Two-Phase Digestion System 总被引:2,自引:0,他引:2
Co-digestion of food waste and dairy manure in a two-phase digestion system was conducted in laboratory scale. Four influents
of R0, R1, R2, and R3 were tested, which were made by mixing food waste with dairy manure at different ratios of 0:1, 1:1,
3:1, and 6:1, respectively. For each influent, three runs of experiments were performed with the same overall hydraulic retention
time (HRT) of 13 days but different HRT for acidification (1, 2, and 3 days) and methanogenesis (12, 11, and 10 days) in two-phase
digesters. The results showed that the gas production rate (GPR) of co-digestion of food waste with dairy manure was enhanced
by 0.8–5.5 times as compared to the digestion with dairy manure alone. Appropriate HRT for acidification was mainly determined
by the biodegradability of the substrate digested. Three-, 2-, and 1-day HRT for acidification were found to be optimal for
the digestion of R0, R1, and R2/R3, respectively, when overall HRT of 13 days was used. The highest GPR of 3.97 L/L·day was
achieved for R3(6:1) in Run 1 (1 + 12 days), therefore, the mixing ratio of 6:1 and HRT of 1 day for acidification were considered
to be the optimal ones and thus recommended for co-digestion of food waste and dairy manure. There were close correlations
between degradation of organic matters and GPR. The highest VS removal rate was achieved at the same HRT for acidification
and mixing ratio of food waste and dairy manure as GPR in the co-digestion. The two-phase digestion system showed good stability,
which was mainly attributed to the strong buffering capacity with two-phase system and the high alkalinity from dairy manure
when co-digested with food waste. 相似文献
10.
K. Opoku-Gyamfi Zahra M. Tafreshi A. A. Adesina 《Reaction Kinetics and Catalysis Letters》1998,64(2):229-238
The methane oxidation activities of Pt−NiO and Co−NiO bimetallic catalysts have been investigated as part of a larger research
program on the autothermal reforming of methane (combined methane oxidation and steam reforming) in a fluidized bed reactor.
Experiments at atmospheric pressure and 783–1023 K for both catalysts showed that the reaction was more selective towards
H2 production at CH4∶O2 ratios greater than unity. Light-off temperature increased with decreasing CH4∶O2 ratios, but increase in gas velocity (beyond minimum fluidization) increased the light-off temperature. Co−NiO was as promising
as the more expensive Pt−NiO catalyst for the oxidation. 相似文献
11.
《中国化学快报》2023,34(2):107439
The horizontal flow anaerobic digester indicated that high ammonia (2923 mg/L) and SO42? (3653 mg/L) would influence the performance of methane production with food waste as substrates. Therefore, bottle anaerobic digestion reactors were carried out to investigate the effect of ammonia/sulfate concentrations on the methane production. Experimental results manifested that the anaerobic digesters with an ammonia concentration of 3500 mg/L or sulfate of 1600 mg/L showed the best performance of methane production, with an average methane yield of 0.32 and 0.33 L (g VS)?1 d?1, respectively. Specifically, a higher ammonia (6500 mg/L) or sulfate (1600-3500 mg/L) level hindered the bioconversion of C from liquid to gas phase (2.68% or 1.73% CH4-Gas, respectively), while insignificantly for the hydrolyzation of C and N from solid to liquid phase. Similar to sulfate, high ammonia nitrogen seriously inhibited the methanation process, leading to a significant carbon accumulation in the anaerobic reactor, especially for propionic acid. The predominant archaea Methanosarcina at genus level indicated that aceticlastic methanogenesis was the major methanogenic pathway. Meanwhile, high ammonia level suppressed the activity of Methanosarcina, while modest sulfate improved H2-consuming methanogens activity. A large fraction of unclassified bacteria within the Firmicutes (43.78%-63.17%) and Bacteroidetes (24.20%-33.30%) phylum played an important role in substrates hydrolysis. 相似文献
12.
Bombardiere J Espinosa-Solares T Domaschko M Chatfield M 《Applied biochemistry and biotechnology》2007,137(1-12):765-775
The effect of feed-loading frequency on digester performance was studied on a thermophilic anaerobic digester with a working volume of 27.43 m(3). The digester was fed 0.93 m(3) of chicken-litter slurry/d, containing 50.9 g/L chemical oxygen demand. The treatments were loading frequencies of 1, 2, 6, and 12 times/d. The hourly pH, biogas production, and methane percent of the biogas were less stable at lower feed frequencies. There was no statistical difference among treatments in methanogenic activity. The feed-loading frequency of six times per day treatment provided the greatest biogas production. 相似文献
13.
Kim Jung K. Cho Jae H. Lee Jung S. Hahm Kyung S. Park Don H. Kim Si W. 《Applied biochemistry and biotechnology》2002,98(1-9):753-764
We developed a process for production of methane at a pilot scale. This process consists of three stages. The first stage
is a semianaerobic hydrolysis/acidogenic step in which organic wastes are converted to various sugars, amino acids, and volatile
fatty acids (VFAs). Operation temperature and pH were 45°C, and 5.0–5.5, respectively. Hydraulic retention time (HRT) was
2 d. To remove the putrid odor and to enhance the hydrolysis of organic wastes, a mixture of bacteria isolated from landfill
soil was inoculated into the reactor. Total chemical oxygen demand (tCOD) and biological oxygen demand (BOD) were 36,000 mg/L
and 40,000 mg/L, respectively. The second stage was an anaerobic acidogenic process, which can produce large amount of VFAs
including acetate, propionate, butyrate, valerate, and caproate. Operation temperature and pH were 35°C, and 5.0–5.5, respectively.
HRT was 2 d. The third stage was a strictly anaerobic methane fermentation step producing methane and carbon dioxide from
VFAs. The working volume of upflow anaerobic sludge blanket (UASB) type reactor was 1200 L, and operation temperature and
pH were 41°C, and 7.7–7.9, respectively. HRT was 12 d. Seventy two percent of methane at maximum was generated and the yield
was 0.45–0.50 m3/kg VS of food wastes. Through the process, 88% of tCOD and 95% of BOD were removed. The wastewater was treated with the biological
aerobic and anaerobic filters immobilized with heterotrophic and autotrophic nitrifying and denitrifying bacteria. Ninety
percent of total nitrogen (T-N) was removed by this treatment. The residual T-N and total phosphorous (T-P) were removed by
the algal periphyton treatment system. The final concentrations of nitrogen and phosphorous in the drain water were 53 and
7 mg/L, respectively. 相似文献
14.
《中国化学快报》2022,33(6):3106-3112
Considering that cathode of microbial electrochemical system (MES) is a good electrons source for methane production via direct/indirect electron transfer to electroactive microorganisms, and that Fe(0) is also a confirmed electron donor for some electroactive microorganisms through metal-microbe direct electron transfer (DET), Fe(0)-cathode was equipped into an MES digester to enhance cathodic methane production. The results of this study indicated that the potential DET participator, Clostridium possibly obtained electrons directly from Fe(0)-cathode via metal-microbe electrons transfer, then transferred electrons directly to the definite DET participators, Methanosarcina/Methanothrix via microbe-microbe electrons transfer for CH4 production. In addition, Methanobacterium is another specially enriched methanogen on Fe(0)-cathode, which might obtain electrons directly from Fe(0)-cathode to produce CH4 via metal/electrode-microbe DET. The increment of conductivity of cathodic sludge in Fe(0)-cathode MES digester (R1) further confirmed the enrichment of electroactive microorganisms participating in DET process. As a consequence, a higher CH4 production (1205–1508 mL/d) and chemical oxygen demand (COD) removal (79.0%-93.8%) were achieved in R1 compared with graphite-cathode MES digester (R2, 720–1090 mL/d and 63.6%-85.6%) and the conventional anaerobic digester (R3, 384–428 mL/d and 35.2%-41.0%). In addition, energy efficiency calculated indicated that the output energy of CH4 production was 8.16 folds of electricity input in Fe(0)-cathode MES digester. 相似文献
15.
Four 3–L aerobic biofilm reactors (ABRI, 2, 3, and 4) treating a highstrength food–processing waste water (10 g chemical oxygen
demand [COD]/L) were subject to reactor liquor recirculation rates of 1, 3,15, and 30 L/h, respectively. Treatment performance
in terms of COD removal rates of ABRI, 2, and 3 were similar at hydraulic loads of 2.0 g COD/L/d and below. At higher organic
loads, ABR3 could achieve a COD removal rate that was over two times higher than that of ABRI and 2. ABR3 could be operated
at a maximum organic load that was two times higher than that of ABRI and 2. ABR4 experienced a biofilm sloughing from the
packing medium at the beginning of operation. Tracer studies showed that recirculation rate of 1 L/h resulted in a plug–flow
pattern in the packed bed of the reactor. On the other hand, recirculation rate of 15 L/h, which was equivalent to recirculating
the reactor liquor five times per hour, provided effective mixing in the packed bed. Superior performance of ABR3 was attributed
to the effective recirculation of reactor liquor, which diluted and distributed the influent, particularly the oil and grease
components. 相似文献
16.
Liliana B. Pierella Linsheng Wang Oscar A. Anunziata 《Reaction Kinetics and Catalysis Letters》1997,60(1):101-106
Conversion of pure methane and natural gas with different methane purity to aromatic hydrocarbons at. 773 and 873 K have been
investigated. Conversion of methane to aromatics under non-oxidizing conditions can be initiated by higher hydrocarbon mixtures
in the feed and, some special coke deposited on Mo/HZSM-5 catalyst at lower reaction temperature. Methane conversion of about
10–20% is obtained at 773 K. The possible reaction mechanism and product phase transformation process for conversion of pure
methane and natural gas at lower temperature are proposed. The thermodynamic limitation for methane conversion under non-oxidizing
conditions may be circumvented. 相似文献
17.
S. A. Solov’ev E. V. Gubareni Ya. P. Kurilets 《Theoretical and Experimental Chemistry》2008,44(6):368-373
It has been established that oxides of the rare-earth elements with moderate redox potentials (La2O3, CeO2) increased the activity and working stability of Ni-Al2O3/cordierite catalysts in the reactions of deep and partial oxidation of methane. In the presence of the (NiO + La2O3 + Al2O3)/cordierite catalyst the process of carbon dioxide conversion of methane can be intensified by introduction of oxygen into
the reaction gas mixture which decreases the temperature to achieve high conversion to 75–100 °C and has practically no effect
on selectivity with respect to H2.
Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 44, No. 6, pp. 359–364, November–December, 2008. 相似文献
18.
Zhang Yin Pan Li Gao Chunguang Zhao Yongxiang 《Journal of Sol-Gel Science and Technology》2011,58(2):572-579
The preparation of ZrO2–SiO2 mixed oxide has been carried out simply by heating an alcohol-aqueous mixture. Preparation conditions such as volume ratio
of alcohol to water and prehydrolysis time of tetraethoxysilane had more important effect on the homogeneity of mixed oxide.
A self-catalytic effect on the resultant Zr–O–Si formation is observed. By employing FT-IR, XRD, NH3-TPD and pyridine adsorption FT-IR techniques, the mixing homogeneity of the mixed oxides in terms of the amount of Zr–O–Si
hetero-linkages has been investigated in detail. The results indicate that the amount of Zr–O–Si hetero-linkages increases
with the increase of ZrO2 content in mixed oxides. Moreover, the phase segregation and acidity generation of mixed oxides are studied and factors responsible
for good mixing are also discussed. Using this approach, a series of highly homogeneous mixed oxides with ZrO2 content of 20–70 mol% are obtained at the optimized preparation condition. 相似文献
19.
Chynoweth D. P. Bosch G. Earle J. F. K. Legrand Robert Liu Kexin 《Applied biochemistry and biotechnology》1991,(1):421-432
A novel process has been developed and evaluated in a pilotscale program for conversion of the biodegradable fraction of municipal
solid waste (MSW) to methane via anaerobic composting. The sequential batch anaerobic composting (SEBAC) process employs leachate
management to provide organisms, moisture, and nutrients required for rapid conversion of MSW and removal of inhibitory fermentation
products during start-up. The biodegradable organic materials are converted to methane and carbon dioxide in 21–42 d, rather
than the years required in landfills. 相似文献
20.
Kinetics of biomethanation of solid tannery waste and the concept of interactive metabolic control 总被引:1,自引:0,他引:1
Anaerobic digestion of calf skin collagenous waste was optimized for a batch process based on accelerated maximal methane
yield per gram of input volatile solid. A kinetic analysis with respect to changes in the levels of volatile solid, collagen,
amino sugars, amino acids, hydroxyproline, ammonium ions, and volatile fatty acid were followed for a period of 80 d. Distinct
metabolic phases included an initial high rate collagenolysis for 4 d, with 50% degradation and was followed by an acidogenic
phase between 4–12 d with voltatile fatty acids levels increasing to 215 mmol/L. Subsequently methanogenesis ensued and was
maximal between 12–24 d when volatile fatty acids attained steady state levels. During the period of 80 d, the overall decrease
in volatile solid level was 65%, whereas the collagen level declined by 85% with 0.45 L of methane yield/g of volatile solid
degraded. Based on the levels of various metabolites detected, the concept of interactive metabolic control earlier proposed
has been validated. 相似文献