Anaerobic digestion of alfalfa silage with recirculation of process liquid

Nordberg, Åke; Jarvis, Åsa; Stenberg, Bo; Mathisen, Berit; Svensson, Bo

doi:10.1016/j.biortech.2005.11.027

Cited by 85 publications

(38 citation statements)

References 25 publications

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“…The influence of OLR on y from the investigated energy crops was found to be different and depends on k. At the mono-fermentation of beet silage the influence cannot be described satisfactorily by Equation (10) …”

Section: Discussionmentioning

confidence: 93%

“…Results from semi-continuous longterm experiments for anaerobic digestion of energy crops and cattle slurry in CSTR under mesophilic conditions have shown that the effect of organic loading rate OLR on VS-biogas yield y can be nearly described in three of four cases by a simple kinetic model by means of Equation (10). This is based on c 0 , the theoretical maximum biogas yield y max , the reaction rate constant k and the densities of the effluent ρ E and the biogas ρ G , which are all substrate-or process-specific.…”

Section: Discussionmentioning

confidence: 99%

“…It can be seen that beet silage results in the highest biogas yield with a theoretical maximum of 0.93 m 3 kg − 1 and a very small dependence of y on OLR. According to this, the biogas production from fodder beet silage occurs with a high reaction rate and y cannot be explained by Equation (10) satisfactorily. This is expressed in a low value R 2 with 8% and a high value k of 0.32 d − 1 .…”

Section: Equalization Of Equationsmentioning

confidence: 93%

“…With respect to energy crops as a single substrate in mono-digestion pioneer work was performed with sorghum ( Sorghum bicolor ), napiergrass ( Pennisetum purpureum ), corn ( Zea mays ), and sorghum/alpha-cellulose in mix experiments about 15 years ago [3]. Further laboratory-, pilotand farm-scale experiments were conducted to obtain kinetic data for anaerobic digestion of energy crops and crop residues [4][5][6][7][8][9][10][11]. Numerous full-scale biogas plants are in operation and digest mainly maize silage, whole crop cereal silage and mixtures of other energy crops.…”

Section: Introductionmentioning

confidence: 99%

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Kinetic study of biogas production from energy crops and animal waste slurry: Effect of organic loading rate and reactor size

Mähnert

Linke

2009

Environmental Technology

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To cite this article: P. Mähnert & B. Linke (2009) Biogas production in agriculture is processed mostly continuously at mesophilic temperatures in completely stirred tank reactors. Therefore, reactor performance data were studied in long-term semi-continuous laboratory-scale experiments with maize silage, whole-crop rye silage and fodder beet silage as mono-substrate and cattle slurry at mesophilic temperatures. For calculation of biogas yield as function of the organic loading rate, a hyperbolic equation was developed on the base of a first-order reaction rate for substrate degradation. The biogas yield depends also on the maximum biogas yield, the concentration of volatile solids of the input, the density of the effluent, the density of the biogas and the reaction rate constant, which are all substrate-or process-specific. Values of the theoretical maximum biogas yield and the reaction rate constant were observed in the range 0.61-0.93 m 3 per kg volatile solids and 0.032 -0.316 d − 1 , respectively. By means of the hyperbolic equation, the proportion of the biogas yield from the maximum can be calculated for the first and a second reactor which also depends on the volume of each reactor. Keywords: biogas yield; modelling; organic loading rate IntroductionSince the amendment of the Renewable Energy Sources Act in Germany (Erneuerbare Energien Gesetz) the utilization of energy crops for biogas production has become more cost-effective. The treatment of animal waste slurry and energy crops in co-digestion is a proven technology and recently interest has grown in the potential of using anaerobic processes [1,2]. With respect to energy crops as a single substrate in mono-digestion pioneer work was performed with sorghum ( Sorghum bicolor ), napiergrass ( Pennisetum purpureum ), corn ( Zea mays ), and sorghum/alpha-cellulose in mix experiments about 15 years ago [3]. Further laboratory-, pilotand farm-scale experiments were conducted to obtain kinetic data for anaerobic digestion of energy crops and crop residues [4][5][6][7][8][9][10][11]. Numerous full-scale biogas plants are in operation and digest mainly maize silage, whole crop cereal silage and mixtures of other energy crops.The financial success of a biogas plant results from the quality and the biogas yield of the applied substrate and the process engineering. However, agricultural biogas plants in practice are mostly processed intuitively because the measurement engineering is not improved adequately. Additionally, for energy crops the experience is difficult to generalize because of the great diversity of substrates. Furthermore, high-energetic

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Equalization Of Equationsmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Kinetic study of biogas production from energy crops and animal waste slurry: Effect of organic loading rate and reactor size

Mähnert

Linke

2009

Environmental Technology

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“…• adjustment of the carbon to nitrogen ratio with nutrients addition or co-digestion; 71,72 • addition of trace metals; [73][74][75][76] • integration of cost-ef ective thermochemical or/and enzymatic pre-treatments;…”

Section: Concerns and Future Trends For The Optimization Of The Net Ementioning

confidence: 99%

Biomethane production from starch and lignocellulosic crops: a comparative review

Frigon

Guiot

2010

Biofuels Bioprod Bioref

218

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The methane produced from the anaerobic digestion of organic wastes and energy crops represents an elegant and economical means of generating renewable biofuel. Anaerobic digestion is a mature technology and is already used for the conversion of the organic fraction of municipal solid wastes and excess primary and secondary sludge from waste‐water treatment plants. High methane yield up to 0.45 m3 STP CH4/kg volatile solids (VS) or 12 390 m3 STP CH4/ ha can be achieved with sugar and starch crops, although these cultures are competing with food and feed crops for high‐quality land. The cultivation of lignocellulosic crops on marginal and set‐aside lands is a more environmentally sound and sustainable option for renewable energy production. The methane yield obtained from these crops is lower, 0.17–0.39 m3 STP CH4/kg VS or 5400 m3 STP CH4/ha, as its conversion into methane is facing the same initial barrier as for the production of ethanol, for example, hydrolysis of the crops. Intensive research and development on efficient pre‐treatments is ongoing to optimize the net energy production, which is potentially greater than for liquid biofuels, since the whole substrate excepted lignin is convertible into methane. Copyright © 2010 Crown in the right of Canada

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Biogas Production: New Trends for Alternative Energy Sources in Rural and Urban Zones

2009

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Biogas is a biofuel with a high energy value and basically consisting of methane, which can be used as a renewable energy source as a substitute for natural gas or liquefied petroleum gas. It can be produced by anaerobic digestion of agricultural organic waste or manure in rural areas, where it can be used to generate electric, thermal or mechanical energy. It can also be generated in landfills from the organic fraction of municipal solid wastes and used as an alternative energy source in urban areas. Industrialized and urbanized areas are afflicted by serious environmental problems associated with the generation of organic residues. Anaerobic microorganisms can degrade pollutants resulting in two kinds of products, i.e., digested sludge and biogas, which can be exploited as a soil fertilizer and a renewable energy source, respectively. The correct management of residual waste involves high costs, and inadequate treatment and storage can compromise its quality. Environmental agencies have been encouraging the dissemination of anaerobic digesters to produce biogas from organic residues and the use of the resulting sludge as fertilizer since it is able to destroy pathogenic agents and reduce the humidity level. This review aims to evaluate the production capability of biogas and its application as an alternative energy source in rural and urban areas. Clean EnergyEnergy has been the sustaining basis of civilization, because it has historically promoted the economic, social and cultural development of mankind. Nowadays, renewable energy sources are gaining significant interest, because they promise to be a feasible alternative to the problems relating to future oil shortage, the difficulty of setting up hydroelectric and thermoelectric powers, and the so-called "dirty energies", e.g., mineral coal, oil shale, etc. Energy demand has been increasing as the worlds' economies grow, bringing an associated change in consumption patterns, which in turn, vary depending on the source and availability of the energy source, conversion loss and end use efficiency.The term "alternative energy source" is used not only to indicate an efficient alternative; it is also synonymous with clean, pure, non-polluting energy, which is, in principle, inexhaustible and can be found everywhere. The electric energy generated by clean and renewable sources is the result of the environmentally friendly exploitation of abundant natural resources. Moreover, the use of clean energies such as solar and wind energies, biomass, biogas and hydroelectric power would allow the diversification of the supply, ensuring long term energy availability, reducing the emissions of greenhouse gases, and increasing the employment opportunities in both rural and urban areas.In recent years, public and political sensitivities to environmental issues and energy security have led to the promotion of renewable energy resources. Among these resources, biomass could play a substantial role in a more diverse and sustainable mix of energies, and biogas can be produced by u...

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Anaerobic digestion of alfalfa silage with recirculation of process liquid

Cited by 85 publications

References 25 publications

Kinetic study of biogas production from energy crops and animal waste slurry: Effect of organic loading rate and reactor size

Kinetic study of biogas production from energy crops and animal waste slurry: Effect of organic loading rate and reactor size

Biomethane production from starch and lignocellulosic crops: a comparative review

Biogas Production: New Trends for Alternative Energy Sources in Rural and Urban Zones

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