Any biogas produced by the anaerobic fermentation of organic materials has the advantage of being an environmentally friendly biofuel.Nevertheless,the relatively low calorific value of such gases makes their effective...Any biogas produced by the anaerobic fermentation of organic materials has the advantage of being an environmentally friendly biofuel.Nevertheless,the relatively low calorific value of such gases makes their effective utilization in practical applications relatively difficult.The present study considers the addition of hydrogen as a potential solution to mitigate this issue.In particular,the properties of turbulent diffusion jet flames and the related pollutant emissions are investigated numerically for different operating pressures.The related numerical simulations are conducted by solving the RANS equations in the frame of the Reynolds Stress Model in combination with the flamelet approach.Radiation effects are also taken into account and the combustion kinetics are described via the GRI-Mech 3.0 reaction model.The considered hydrogen fuel enrichment spans the range from 0%to 50%in terms of volume.Pressure varies between 1 and 10 atm.The results show that both hydrogen addition and pressure increase lead to an improvement in terms of mixing quality and have a significant effect on flame temperature and height.They also reduce CO_(2) emissions but increase NOx production.Prompt NO is shown to be the predominant NO formation mechanism.展开更多
Population growth combined with the rising standard of living of people around the world is the reason for the ever-increasing production of waste which management is costing states a lot of money for its disposal. Am...Population growth combined with the rising standard of living of people around the world is the reason for the ever-increasing production of waste which management is costing states a lot of money for its disposal. Among available waste treatment techniques, landfill is one of the most promoted waste management techniques with the emergence of the bioreactor concept. However, the control of biodegradation parameters in order to accelerate waste stabilization is an important issue. For environmental and economic reasons, the technique of leachate recirculation by injection into the waste is increasingly used to improve the degradation of landfilled waste. The injection of leachate is possible using vertical boreholes, horizontal pipes, infiltration ponds or a combination of these. Indeed, moisture is the main factor in waste degradation and biogas production. The migration of leachate to the bottom of the landfill creates low moisture in the upper areas of the landfill reducing the growth of microbial populations. This results in low or no biogas production. The main objective of the present work is to develop a numerical model of leachate recirculation by injection into the waste to rewet the waste and restart biological activity. The analysis of the results shows that the diffusion of the wet front increases with time and depth. The lateral widening of the wet front is slow in relation to the progression of the wet front towards the bottom of the waste cell. This indicates the predominance of gravity effects over diffusion phenomena. The results reveal that the distributed re-injection is the best mode of leachate recirculation because the moisture distribution on the whole waste mass is totally satisfactory and the biogas generation is more important. Leachate recirculation campaigns should be done periodically to rewet the waste, boost microbial activity and hope for a quicker stabilization of the landfill.展开更多
The present work dealt with the generation, purifying and liquefaction of biomethane to improve energy density using local materials for domestic applications. Cow dung was sourced at JKUAT dairy farm and experiments ...The present work dealt with the generation, purifying and liquefaction of biomethane to improve energy density using local materials for domestic applications. Cow dung was sourced at JKUAT dairy farm and experiments were conducted at JKUAT Bioenergy laboratory using biogas generated in laboratory scale 1 m<sup>3</sup> bioreactors. Experiments were done in triplicates and repeated under different conditions to get the optimal conditions. The results showed that enhanced cow dung substrate displayed an improved fermentation process with increased biogas yields. Purified biogas optimized methane content from 56% ± 0.18% for raw biogas to 95% ± 0.98% for biomethane which was ideal for liquefaction.展开更多
As many think that respect for the environment, is not only a question intended for industrialists but has all the sectors of life, in particular sanitary also. In this regard, our article brings alternative managemen...As many think that respect for the environment, is not only a question intended for industrialists but has all the sectors of life, in particular sanitary also. In this regard, our article brings alternative management of human waste (excrement) to solve the problems that plague our dear beautiful capital, namely: 1) Lack of latrines that meet the standards;2) Emptying of septic tanks directly into the gutters and;3) Water pollution by sewage csompanies. In order to carry out the cartographic analysis of the study area, we used Shapefile data from the OpenStreetMap, Diva-Gis. These different data allowed us, analyzed, to categorize with the software ArArcGIS 0.8.1 to produce different zones according to the cases incurred in the city of Kinshasa. To do this, the analytical method uses the Buswell equation to determine the amount of gas contained in human excrement. Focusing on the analysis of the excrements produced by the population of age superior to 10 years, for 2023, we obtained: 138355.7283 m<sup>3</sup>/day of CH4 (885476.66 kWh/day or 885.476 MWh/day), which, energy can light: 138,355 lamps of 60 to 100 W for six hours or nearly 70,000 lamps of 60 to 100 W for 12 hours. Considering the last one which offers the lowest access rate, i.e. 3% of the district population to these latrines, we have: a) In Tshangu, we produce: 1618.762 <sup>3>/day (10360.07 kWh/day or 10.36 MWh/day) which can light nearly 1600 lamps from 60 to 100 W for six hours or nearly 800 lamps from 60 to 100 W for twelve hours. b) Mont-Amba, we produce 1402.927 <sup>3>/day (8978.73 kWh/day or 8.97 MWh/day) which can light nearly 1400 lamps from 60 to 100 W for six hours or nearly 700 lamps from 60 to 100 W for twelve hours;c) In Lukunga, we produce: 946.35 <sup>3>/day (6056.66 kWh/day or 6.056 MWh/day) which can light nearly 900 lamps from 60 to 100 W for six hours or nearly 450 lamps from 60 to 100 W for twelve hours. d) Funa, we produce: 182.629 <sup>3>/day (1168.83 kWh/day or 1.17 MWh/day) which can light almost 180 lamps from 60 to 100 W for six hours or almost 90 lamps from 60 to 100 W for twelve hours.展开更多
The olive mill waste waters (OMWW) generated from olive oil extraction is a major environmental concern since they are characterized by their role as a pollutant (high organic and mineral matters) and their pH acid. T...The olive mill waste waters (OMWW) generated from olive oil extraction is a major environmental concern since they are characterized by their role as a pollutant (high organic and mineral matters) and their pH acid. The aim of this study was to valorize (OMWW) by anaerobic fermentation in the presence of cow manure in order to produce biogas and reduce their toxic load. Many tests were carried out by fermenting (OMWW) with polyphenols in the presence of cow manure in thermophile temperatures. The performance of this treatment was valuated through measurements of biogas production and by the determination of different parameters of fermented media (pH, volume of the biogas and polyphenols).展开更多
Only 42% of Uganda’s population has access to electricity. The population continues to use firewood and charcoal as a source of energy, which leads to depletion of forests thus to climate change. The purpose of this ...Only 42% of Uganda’s population has access to electricity. The population continues to use firewood and charcoal as a source of energy, which leads to depletion of forests thus to climate change. The purpose of this study was to assess the potential of biogas production from jackfruit waste, banana peels, and pineapple peels when co-digested with cow dung as an alternative energy source. Substrates for each waste were co-digested with varying proportions (0%, 25%, and 50%) of cow dung using laboratory-scale 250 mL anaerobic digestors. The total biogas generation for jackfruit waste, banana peels, and pineapple peels after 30 days of anaerobic digestion was 82.3, 189, and 262 mL, respectively. When jack fruit waste, pineapple peels and banana peels were co-digested with 25% cow dung, the total amount of biogas produced increased by a factor of two and three, respectively. However, 50% of cow dung only significantly (p ≤ 0.05) improved for jack fruit waste by two folds. Therefore, the results indicated that jackfruit waste, banana and pineapple peels can be used for biogas production to augment energy supply. .展开更多
In this paper, an energy system consisting of solar collector, biogas dry reforming reactor and solid oxide fuel cell (SOFC) has been proposed. The heat produced from the concentrating solar collector is used to drive...In this paper, an energy system consisting of solar collector, biogas dry reforming reactor and solid oxide fuel cell (SOFC) has been proposed. The heat produced from the concentrating solar collector is used to drive a biogas dry reforming reactor in order to produce H<sub>2</sub> as a fuel for SOFC, in such as system. The aim of this study is to clarify the impact of climate data on the performance of solar collector with various sizes/designs. The temperature of heat transfer fluid produced by the solar collector is calculated by adopting the climate data for Nagoya city in Japan in 2021. The amount of H<sub>2</sub> produced from the biogas dry reforming reactor and the power generated by SOFC were simulated. The results show the temperature of heat transfer fluid (T<sub>fb</sub>) and T<sub>fb</sub> ratio (a) based on the length of absorber (dx) = 1 m have a peak near the noon following the trend of solar intensity (I). Results also revealed that a increases with increase in dx. It is found that the differences of T<sub>fb</sub> and a between dx = 2 m and dx = 3 m are larger than those between dx = 1 m and dx = 2 m. It is revealed that T<sub>fb</sub> and a are higher in spring and summer. dx = 4 m is the optimum length of solar absorber. The amount of H<sub>2</sub> produced from the biogas dry reforming reactor as well as the power generated by SOFC is the highest in August, resulting that it is prefer to produce H<sub>2</sub> and to generate SOFC in summer.展开更多
S<span>everal challenges are associated </span></span><span style="font-family:"">with</span><span style="font-family:""> the development, adoption and...S<span>everal challenges are associated </span></span><span style="font-family:"">with</span><span style="font-family:""> the development, adoption and de</span><span style="font-family:"">ployment of biogas digesters in developing countries. Amongst these challenges is a comprehensive and systematic procedure for the design of digesters suitable for rural communities. This paper proposes the Flexible Biogas Digester System (FBDS) as a viable option for rural communities in developing countries and provide</span><span style="font-family:"">s</span><span style="font-family:""> a detailed step-by-step procedure for it</span><span style="font-family:"">s</span><span style="font-family:""> design. The biogas production process is a function of the digester operating factors which may be grouped into physical, process and performance parameters. The physical design parameters include</span><span style="font-family:""> </span><span style="font-family:"">the digester volume, the volume of the biogas storage tank, and the volume of the installation pit. The process parameters include total solid content of the slurry (TS), organic loading rate (OLR), digester operating temperatures, pH of the slurry inside the digester. The performance parameters include</span><span style="font-family:""> </span><span style="font-family:"">biogas production rate, biogas productivity and biogas quality. The Net Present Value and the Levelised Cost of Energy are presented for simple economic evaluation of the FBDS.展开更多
Anaerobic digestion technology provides a new approach to treat organic waste while generating </span><span style="font-family:Verdana;">greenhouse gas</span><span style="font-famil...Anaerobic digestion technology provides a new approach to treat organic waste while generating </span><span style="font-family:Verdana;">greenhouse gas</span><span style="font-family:""> </span><span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">GHG</span><span style="font-family:Verdana;">)</span><span style="font-family:""><span style="font-family:Verdana;"> savings. Moreover, the methane gas produced during the process can be used to generate electricity. </span><span style="font-family:Verdana;">In order to</span><span style="font-family:Verdana;"> ensure that Australia stays on its trajectory towards a </span><span style="font-family:Verdana;">carbon neutral</span><span style="font-family:Verdana;"> future, the use of anaerobic digestion technology to treat its abundant organic waste streams should be considered</span></span><span style="font-family:Verdana;">. </span><span style="font-family:Verdana;">Thirty million tonnes</span><span style="font-family:""> </span><span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">Mt</span><span style="font-family:Verdana;">)</span><span style="font-family:Verdana;"> of organic waste was produced in 2017. The use of anaerobic digestion to treat 1 tonne of waste could result in </span><span style="font-family:""><span style="font-family:Verdana;">0.143 </span><span style="font-family:Verdana;">tonne</span><span style="font-family:Verdana;"> of CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">-e in GHG saving</span></span><span style="font-family:Verdana;">s</span><span style="font-family:""><span style="font-family:Verdana;">. In contrast, other more widely employed waste disposal methods such as landfilling, composting </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> incineration may generate GHG emissions. Additionally, the use of methane for electricity production also generates the least GHG emissions per MWh. This is </span><span style="font-family:Verdana;">approximately</span><span style="font-family:Verdana;"> 3 times lower than crude oil, 4 times lower than black coal </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> 5 times lower than brown coal. However, the adoption and implementation of anaerobic digestion technology in Australia face several immediate constraints. Firstly, anaerobic digestion technology is deemed unprofitable, incurring </span><span style="font-family:Verdana;">high</span><span style="font-family:Verdana;"> initial capital cost, operating costs </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> extremely long payback periods. Secondly, there is a lack of government support in terms of a national target for biogas production via anaerobic digestion. This review will provide an in-depth analysis </span><span style="font-family:Verdana;">into</span><span style="font-family:Verdana;"> the current state of the Australian biogas sector. </span><span style="font-family:Verdana;">In addition</span><span style="font-family:Verdana;">, the review discusses the opportunities to make anaerobic digestion technology more financially viable and to accelerate the growth of the Australian biogas sector.展开更多
Biogas can be used as an alternative energy source for producing heat and electricity;however, volatile methylsiloxanes(VOSiC) present in biogas can severely damage heat exchangers, turbines and gas engines. Consequen...Biogas can be used as an alternative energy source for producing heat and electricity;however, volatile methylsiloxanes(VOSiC) present in biogas can severely damage heat exchangers, turbines and gas engines. Consequently, e cient removal of VOSiC from biogas that is used as a biofuel is required. In this work, acetylated silica gel(Ac@SG) was synthesized,via treatment of microporous silica gel(SG) with acetic anhydride as an adsorbent, for removal of VOSiC from biogas,and characterized with XRD, SEM–EDS, N2-BET and FT-IR. This Ac@SG adsorbent exhibited a meso-/microporous structure and hydrophobic surface, indicating it was a more e cient adsorbent for removing hexamethyldisiloxane(L2) and octamethylcyclotetrasiloxane(D4) from biogas samples than conventional SG. It was found that the adsorption capacities of Ac@SG reached 304 mg L2/g for hexamethyldisiloxane and 916 mg D4/g for octamethylcyclotetrasiloxane at lower temperatures in the experimental range, and water had no significant e ect on its absorption e ciency. The used Ac@SG could be easily regenerated by heating it at 110 °C, and the adsorption capacity of recycled Ac@SG for hexamethyldisiloxane and octamethylcyclotetrasiloxane was kept constant in four recycle adsorption experiments.展开更多
Massive amounts of biogas slurry are produced due to the development of biogas plants.The pollution features and the risk of biogas slurry were fully evaluated in this work.Thirty-one biogas slurry samples were collec...Massive amounts of biogas slurry are produced due to the development of biogas plants.The pollution features and the risk of biogas slurry were fully evaluated in this work.Thirty-one biogas slurry samples were collected from sixteen different cities and five different raw materials biogas plants(e.g.cattle manure,swine manure,straw-manure mixture,kitchen waste and chicken manure).The chemical oxygen demand(COD),ammonia nitrogen(NH_(4)^(+)-N),anions(e.g.Cl^(-1),SO_(4)^(2-),NO_(3)^(-)and PO_(4)^(3-)),antibiotics(e.g.sulphonamides,quinolones,β2-receptor agonists,macrolides,tetracyclines and crystal violet)and heavy metals(e.g.Cu,Cd,As,Cr,Hg,Zn and Pb)contents from these biogas slurry samples were systematically investigated.On this basis,risk assessment of biogas slurry was also performed.The concentrations of COD,NH_(4)^(+)-N and PO_(4)^(3-) in biogas slurry samples with chicken manure as raw material were significantly higher than those of other raw materials.Therefore,the biogas slurry from chicken manure raw material demonstrated the most serious eutrophication threat.The antibiotic contents in biogas slurry samples from swine manure were the highest among five raw materials,mostly sulphonamides,quinolones and tetracyclines.Biogas slurry revealed particularly serious arsenic contamination and moderate potential ecological risk.The quadratic polynomial stepwise regression model can quantitatively describe the correlation among NH_(4)^(+)-N,PO_(4)^(3+) and heavy metals concentration of biogas slurry.This work demonstrated a universal potential threat from biogas slurry that can provide supporting data and theoretical basis for harmless treatment and reuse of biogas slurry.展开更多
[C_8min] BF_4 was used in this work to combine with TBAB or THF for the investigation about thermodynamic and kinetic additives on CO_2 and CH_4/CO_2 hydrates. The results show that [C_8min] BF_4 has the inhibition ef...[C_8min] BF_4 was used in this work to combine with TBAB or THF for the investigation about thermodynamic and kinetic additives on CO_2 and CH_4/CO_2 hydrates. The results show that [C_8min] BF_4 has the inhibition effect on the equilibrium of hydrate formation. About the kinetic study, [C_8 min] BF_4 could improve the rate of CO_2 hydrate formation and increase the gas uptake in hydrate phase. At the same time, the combination of TBAB and [C8 min] BF_4 could increase the mole friction of CH_4 in residual gas comparing with the data in THF solution. CH_4 separation efficiency was strongly enhanced. Since that the size of CO_2 and CH_4 molecules are similar, CH_4 and CO_2 could form the similar hydrate, so the recovery of CH_4 from biogas decreases lightly. The CH_4 content in biogas can purified from 67 mol% to 77 mol% after one-stage hydrate formation. In addition, the combination of THF and[C_8 min] BF_4 do not have obvious promoting effect on CH_4 separation comparing with the gas separation results in pure THF solution.展开更多
This study investigated the effects of soluble chemical oxygen demand(s COD),volatile fatty acids(VFAs),and microbial community on biogas production in the process of rice straw(RS)anaerobic digestion(AD).The results ...This study investigated the effects of soluble chemical oxygen demand(s COD),volatile fatty acids(VFAs),and microbial community on biogas production in the process of rice straw(RS)anaerobic digestion(AD).The results showed that the s COD concentrations and VFA production appeared the same trend,which was inversely related with that of daily biogas production.The cumulative methane yield of RS was 194.9 ml·(g VS)^-1·^-1.The modified Gompertz model is the best fit for measured methane yields of RS in the three kinetic models of first-order kinetic,Cone and modified Gompertz.Firmicutes,Bacteroidetes,and Euryarchaeota were the dominant microbial phyla throughout AD process.At the genus level,the microorganisms mainly composed of Clostridium,Vadin,Terrisporobacter,Methanosaeta,Methanobacterium,and Methanosarcina.Proteiniphilum showed strong relationship with s COD and VFA production.Clostridium and Terrisporobacter displayed relationship with biogas production.Therefore,in order to improve the stability of the AD system,the parameter changes of VFAs,s COD,and biogas yield were monitored in the RS AD process.The study can provide theoretical basis for improving the efficiency of RS AD.展开更多
This paper discusses the history and present status of different categories of biogas production in China,most of which are classified into rural household production,agriculture-based engineering production,and indus...This paper discusses the history and present status of different categories of biogas production in China,most of which are classified into rural household production,agriculture-based engineering production,and industry-based engineering production.To evaluate the future biogas production of China,five models including the Hubbert model,the Weibull model,the generalized Weng model,the H-C-Z model,and the Grey model are applied to analyze and forecast the biogas production of each province and the entire country.It is proved that those models which originated from oil research can also be applied to other energy sources.The simulation results reveal that China's total biogas production is unlikely to keep on a fast-growing trend in the next few years,mainly due to a recent decrease in rural household production,and this greatly differs from the previous goal set by the official department.In addition,China's biogas production will present a more uneven pattern among regions in the future.This paper will give preliminary explanation for the regional difference of the three biogas sectors and propose some recommendations for instituting corresponding policies and strategies to promote the development of the biogas industry in China.展开更多
Feedback supply chain is a key structure in the supply chain system, and the development of feedback supply chain for biogas biomass energy is one of the important ways of the rural ecological civilization constructio...Feedback supply chain is a key structure in the supply chain system, and the development of feedback supply chain for biogas biomass energy is one of the important ways of the rural ecological civilization construction. Presently, the efficiency problem of biogas supply chain in rural China has been restricting the development of biogas biomass energy business. This article, on the basis of combination of regulation parameters, describes the dynamic changes in the system, using differential equations integrated with simulation to reveal the rules of regulation parameters to investigate the efficiency problem in the biogas supply chain. First of all, on the basis of the actual situation, the flow level and flow rate system structure model and simulation equation set are established for the biogas energy feedback supply chain from a scale livestock farm to peasant households; On the basis of the differentiability of the simulation equation a third order inhomogeneous differential equation with constant coefficients containing regulative parameters is established for the quantity of biogas stored in the feedback supply chain. A theorem and its corollaries are established for the operating efficiency of supply chain to reveal the change law of the quantity of biogas,the quantity of biogas consumed daily by peasant households and its standard-reaching rate as well as other variables.展开更多
The feasibility of adopting a balanced energy mix mode (domestic solar energy, biogas, coal-fired boiler and radiant floor heating) was proposed. Taking a typical rural residence in Zhengzhou City for example, the stu...The feasibility of adopting a balanced energy mix mode (domestic solar energy, biogas, coal-fired boiler and radiant floor heating) was proposed. Taking a typical rural residence in Zhengzhou City for example, the study through theoretical analysis and calculation showed that such a balanced energy mix is an economic way and efficient in saving energy and reducing air pollution, and elaborated the theoretical feasibility of popularizing such a heat supply mode in rural areas.展开更多
The possibility of anaerobic digestion of high oil waste at high temperatures was explored,and the effects of fat concentration on biogas production via anaerobic digestion were analyzed by batch and continuous experi...The possibility of anaerobic digestion of high oil waste at high temperatures was explored,and the effects of fat concentration on biogas production via anaerobic digestion were analyzed by batch and continuous experiments successively. Besides,the response and recovery of the digestion system to the shock of high concentrations of oil were studied. The results showed that the anaerobic digestion of high oil waste could be carried out,and fat concentration had a significant effect on the anaerobic digestion. In the batch experiments,the process of anaerobic digestion could carry out only when fat concentration was 0-1. 68%,and the average methane content was 46. 42%; with the increase of fat concentration,both methane content and production rate decreased significantly,and the digestion period was extended obviously. When fat concentration exceeded 2. 52%,the anaerobic digestion failed to start,and methane could not be detected in the produced biogas. In the continuous experiments,the system could withstand a certain concentration of fat( 6 g/L),and anaerobic digestion process would be inhibited when it experienced the impact of a high oil load( 26. 7 g/L). Nevertheless,this process could recover quickly after the removal of the impact,and the system could withstand a higher fat concentration( 13 g/L) than before. Furthermore,the volume production rate of biogas was approximately 1 L/( L·d),and methane content was about 55%.展开更多
The application of organic soil amendments is a common practice for increasing soil fertility and soil organic carbon (SOC) content. In recent years, a new product from biogas production, biogas slurry is increasingly...The application of organic soil amendments is a common practice for increasing soil fertility and soil organic carbon (SOC) content. In recent years, a new product from biogas production, biogas slurry is increasingly applied to agricultural soils, although little is known about its effects on soil properties. In this study, the influence of this new product in comparison with liquid manure and sewage sludge on the organic carbon dynamics and enzyme activities were investigated in two different agricultural soils in short-term incubation studies. As a control, biologically inert sand was also amended with these organic wastes. In sand, biogas slurry degraded to 10.4% within 14 days, while no differences were found between the degradability of liquid manure and sewage sludge with 6.6% and 5.4%, respectively. However, although the degradability of biogas slurry was highest among the organic amendments, liquid manure application resulted in the highest respiration rates in the soil samples. This was likely due to the organic waste borne easily decomposable substrates which were most dominant in liquid manure. Organic waste applications were found to generally increase the activity of numerous enzymes but did not change the soil enzyme patterns. Thus, in general it was shown that the microbial population of the organic wastes will not become prominent when introduced with the manures to soils. Thus, an inoculation with organic waste borne microorganisms could likely be neglected when discussing the extent of organic carbon dynamics after organic waste application to agricultural soils.展开更多
Water hyacinth, E. crassipes, an invasive water weed thrives in fresh water bodies causing serious environmental problems. In Kenya the weed has invaded Lake Victoria and poses great socioeconomic and environmental ch...Water hyacinth, E. crassipes, an invasive water weed thrives in fresh water bodies causing serious environmental problems. In Kenya the weed has invaded Lake Victoria and poses great socioeconomic and environmental challenges. Currently the weed is harvested from the Lake and left in the open to rot and decay leading to loss of aesthetics, land and air pollution. There is therefore need for development of value addition and economic exploitation strategies. The aim of the study is to assess the potential for utilization of the weed as a renewable energy resource for biogas production. Samples were collected from Lake Victoria, pulped and blend with cow dung at a ratio of 3:1 as inoculum. The resultant mixture was mixed with water at a ratio of 1:1 and fed into a 6 m3 tubular digester. The digester was recharged with 20 kg after every three days. The temperature, pH variations, gas compositions, upgrading and gas yields were studied. The temperature ranged between 22.8°C - 36.6°C and pH 7.4 - 8.5. Biogas was found to contain 49% - 53% methane (CH4 ), 30% - 33% carbon dioxide (CO2 ), 5% - 6% nitrogen (N2 ) and traces of hydrogen sulphide (H2S). The biogas was upgraded using solid adsorbents and wet scrubbers increasing the methane content by up to 70% - 76%. The upgraded gas was used to power internal combustion engines coupled with an electricity generator and direct heat applications. The study concludes that E. crassipes is a potential feedstock for biogas production especially in areas where it is abundant.展开更多
Glycyrrhiza glabra,Mint,Cuminum cyminum,Lavender and Arctium medicinal are considered as edible plants with therapeutic properties and as medicinal plants in Iran.After extraction process of medicinal plants,residual ...Glycyrrhiza glabra,Mint,Cuminum cyminum,Lavender and Arctium medicinal are considered as edible plants with therapeutic properties and as medicinal plants in Iran.After extraction process of medicinal plants,residual wastes are not suitable for animal feed and are considered as waste and as an environmental threat.At present there is no proper management of waste of these plants and they are burned or buried.The present study discusses the possibility of biogas production from Glycyrrhiza Glabra Waste(GGW),Mentha Waste(MW),Cuminum Cyminum Waste(CCW),Lavender Waste(LW)and Arctium Waste(AW).250 g of these plants with TS of 10%were digested in the batch type reactors at the temperature of 35℃.The highest biogas production rate were observed to be 13611 mL and 13471 mL for CCW and GGW(10%TS),respectively.While the maximum methane was related to GGW with a value of 9041 mL(10%TS).The highest specific biogas and methane production were related to CCW with value of 247.4 mL.(g.VS)-1 and 65.1 mL.(g.VS)-1,respectively.As an important result,it was obvious that in lignocellulose materials,it cannot be concluded that the materials with similar ratio of C/N has the similar digestion and biogas production ability.展开更多
文摘Any biogas produced by the anaerobic fermentation of organic materials has the advantage of being an environmentally friendly biofuel.Nevertheless,the relatively low calorific value of such gases makes their effective utilization in practical applications relatively difficult.The present study considers the addition of hydrogen as a potential solution to mitigate this issue.In particular,the properties of turbulent diffusion jet flames and the related pollutant emissions are investigated numerically for different operating pressures.The related numerical simulations are conducted by solving the RANS equations in the frame of the Reynolds Stress Model in combination with the flamelet approach.Radiation effects are also taken into account and the combustion kinetics are described via the GRI-Mech 3.0 reaction model.The considered hydrogen fuel enrichment spans the range from 0%to 50%in terms of volume.Pressure varies between 1 and 10 atm.The results show that both hydrogen addition and pressure increase lead to an improvement in terms of mixing quality and have a significant effect on flame temperature and height.They also reduce CO_(2) emissions but increase NOx production.Prompt NO is shown to be the predominant NO formation mechanism.
文摘Population growth combined with the rising standard of living of people around the world is the reason for the ever-increasing production of waste which management is costing states a lot of money for its disposal. Among available waste treatment techniques, landfill is one of the most promoted waste management techniques with the emergence of the bioreactor concept. However, the control of biodegradation parameters in order to accelerate waste stabilization is an important issue. For environmental and economic reasons, the technique of leachate recirculation by injection into the waste is increasingly used to improve the degradation of landfilled waste. The injection of leachate is possible using vertical boreholes, horizontal pipes, infiltration ponds or a combination of these. Indeed, moisture is the main factor in waste degradation and biogas production. The migration of leachate to the bottom of the landfill creates low moisture in the upper areas of the landfill reducing the growth of microbial populations. This results in low or no biogas production. The main objective of the present work is to develop a numerical model of leachate recirculation by injection into the waste to rewet the waste and restart biological activity. The analysis of the results shows that the diffusion of the wet front increases with time and depth. The lateral widening of the wet front is slow in relation to the progression of the wet front towards the bottom of the waste cell. This indicates the predominance of gravity effects over diffusion phenomena. The results reveal that the distributed re-injection is the best mode of leachate recirculation because the moisture distribution on the whole waste mass is totally satisfactory and the biogas generation is more important. Leachate recirculation campaigns should be done periodically to rewet the waste, boost microbial activity and hope for a quicker stabilization of the landfill.
文摘The present work dealt with the generation, purifying and liquefaction of biomethane to improve energy density using local materials for domestic applications. Cow dung was sourced at JKUAT dairy farm and experiments were conducted at JKUAT Bioenergy laboratory using biogas generated in laboratory scale 1 m<sup>3</sup> bioreactors. Experiments were done in triplicates and repeated under different conditions to get the optimal conditions. The results showed that enhanced cow dung substrate displayed an improved fermentation process with increased biogas yields. Purified biogas optimized methane content from 56% ± 0.18% for raw biogas to 95% ± 0.98% for biomethane which was ideal for liquefaction.
文摘As many think that respect for the environment, is not only a question intended for industrialists but has all the sectors of life, in particular sanitary also. In this regard, our article brings alternative management of human waste (excrement) to solve the problems that plague our dear beautiful capital, namely: 1) Lack of latrines that meet the standards;2) Emptying of septic tanks directly into the gutters and;3) Water pollution by sewage csompanies. In order to carry out the cartographic analysis of the study area, we used Shapefile data from the OpenStreetMap, Diva-Gis. These different data allowed us, analyzed, to categorize with the software ArArcGIS 0.8.1 to produce different zones according to the cases incurred in the city of Kinshasa. To do this, the analytical method uses the Buswell equation to determine the amount of gas contained in human excrement. Focusing on the analysis of the excrements produced by the population of age superior to 10 years, for 2023, we obtained: 138355.7283 m<sup>3</sup>/day of CH4 (885476.66 kWh/day or 885.476 MWh/day), which, energy can light: 138,355 lamps of 60 to 100 W for six hours or nearly 70,000 lamps of 60 to 100 W for 12 hours. Considering the last one which offers the lowest access rate, i.e. 3% of the district population to these latrines, we have: a) In Tshangu, we produce: 1618.762 <sup>3>/day (10360.07 kWh/day or 10.36 MWh/day) which can light nearly 1600 lamps from 60 to 100 W for six hours or nearly 800 lamps from 60 to 100 W for twelve hours. b) Mont-Amba, we produce 1402.927 <sup>3>/day (8978.73 kWh/day or 8.97 MWh/day) which can light nearly 1400 lamps from 60 to 100 W for six hours or nearly 700 lamps from 60 to 100 W for twelve hours;c) In Lukunga, we produce: 946.35 <sup>3>/day (6056.66 kWh/day or 6.056 MWh/day) which can light nearly 900 lamps from 60 to 100 W for six hours or nearly 450 lamps from 60 to 100 W for twelve hours. d) Funa, we produce: 182.629 <sup>3>/day (1168.83 kWh/day or 1.17 MWh/day) which can light almost 180 lamps from 60 to 100 W for six hours or almost 90 lamps from 60 to 100 W for twelve hours.
文摘The olive mill waste waters (OMWW) generated from olive oil extraction is a major environmental concern since they are characterized by their role as a pollutant (high organic and mineral matters) and their pH acid. The aim of this study was to valorize (OMWW) by anaerobic fermentation in the presence of cow manure in order to produce biogas and reduce their toxic load. Many tests were carried out by fermenting (OMWW) with polyphenols in the presence of cow manure in thermophile temperatures. The performance of this treatment was valuated through measurements of biogas production and by the determination of different parameters of fermented media (pH, volume of the biogas and polyphenols).
文摘Only 42% of Uganda’s population has access to electricity. The population continues to use firewood and charcoal as a source of energy, which leads to depletion of forests thus to climate change. The purpose of this study was to assess the potential of biogas production from jackfruit waste, banana peels, and pineapple peels when co-digested with cow dung as an alternative energy source. Substrates for each waste were co-digested with varying proportions (0%, 25%, and 50%) of cow dung using laboratory-scale 250 mL anaerobic digestors. The total biogas generation for jackfruit waste, banana peels, and pineapple peels after 30 days of anaerobic digestion was 82.3, 189, and 262 mL, respectively. When jack fruit waste, pineapple peels and banana peels were co-digested with 25% cow dung, the total amount of biogas produced increased by a factor of two and three, respectively. However, 50% of cow dung only significantly (p ≤ 0.05) improved for jack fruit waste by two folds. Therefore, the results indicated that jackfruit waste, banana and pineapple peels can be used for biogas production to augment energy supply. .
文摘In this paper, an energy system consisting of solar collector, biogas dry reforming reactor and solid oxide fuel cell (SOFC) has been proposed. The heat produced from the concentrating solar collector is used to drive a biogas dry reforming reactor in order to produce H<sub>2</sub> as a fuel for SOFC, in such as system. The aim of this study is to clarify the impact of climate data on the performance of solar collector with various sizes/designs. The temperature of heat transfer fluid produced by the solar collector is calculated by adopting the climate data for Nagoya city in Japan in 2021. The amount of H<sub>2</sub> produced from the biogas dry reforming reactor and the power generated by SOFC were simulated. The results show the temperature of heat transfer fluid (T<sub>fb</sub>) and T<sub>fb</sub> ratio (a) based on the length of absorber (dx) = 1 m have a peak near the noon following the trend of solar intensity (I). Results also revealed that a increases with increase in dx. It is found that the differences of T<sub>fb</sub> and a between dx = 2 m and dx = 3 m are larger than those between dx = 1 m and dx = 2 m. It is revealed that T<sub>fb</sub> and a are higher in spring and summer. dx = 4 m is the optimum length of solar absorber. The amount of H<sub>2</sub> produced from the biogas dry reforming reactor as well as the power generated by SOFC is the highest in August, resulting that it is prefer to produce H<sub>2</sub> and to generate SOFC in summer.
文摘S<span>everal challenges are associated </span></span><span style="font-family:"">with</span><span style="font-family:""> the development, adoption and de</span><span style="font-family:"">ployment of biogas digesters in developing countries. Amongst these challenges is a comprehensive and systematic procedure for the design of digesters suitable for rural communities. This paper proposes the Flexible Biogas Digester System (FBDS) as a viable option for rural communities in developing countries and provide</span><span style="font-family:"">s</span><span style="font-family:""> a detailed step-by-step procedure for it</span><span style="font-family:"">s</span><span style="font-family:""> design. The biogas production process is a function of the digester operating factors which may be grouped into physical, process and performance parameters. The physical design parameters include</span><span style="font-family:""> </span><span style="font-family:"">the digester volume, the volume of the biogas storage tank, and the volume of the installation pit. The process parameters include total solid content of the slurry (TS), organic loading rate (OLR), digester operating temperatures, pH of the slurry inside the digester. The performance parameters include</span><span style="font-family:""> </span><span style="font-family:"">biogas production rate, biogas productivity and biogas quality. The Net Present Value and the Levelised Cost of Energy are presented for simple economic evaluation of the FBDS.
文摘Anaerobic digestion technology provides a new approach to treat organic waste while generating </span><span style="font-family:Verdana;">greenhouse gas</span><span style="font-family:""> </span><span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">GHG</span><span style="font-family:Verdana;">)</span><span style="font-family:""><span style="font-family:Verdana;"> savings. Moreover, the methane gas produced during the process can be used to generate electricity. </span><span style="font-family:Verdana;">In order to</span><span style="font-family:Verdana;"> ensure that Australia stays on its trajectory towards a </span><span style="font-family:Verdana;">carbon neutral</span><span style="font-family:Verdana;"> future, the use of anaerobic digestion technology to treat its abundant organic waste streams should be considered</span></span><span style="font-family:Verdana;">. </span><span style="font-family:Verdana;">Thirty million tonnes</span><span style="font-family:""> </span><span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">Mt</span><span style="font-family:Verdana;">)</span><span style="font-family:Verdana;"> of organic waste was produced in 2017. The use of anaerobic digestion to treat 1 tonne of waste could result in </span><span style="font-family:""><span style="font-family:Verdana;">0.143 </span><span style="font-family:Verdana;">tonne</span><span style="font-family:Verdana;"> of CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">-e in GHG saving</span></span><span style="font-family:Verdana;">s</span><span style="font-family:""><span style="font-family:Verdana;">. In contrast, other more widely employed waste disposal methods such as landfilling, composting </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> incineration may generate GHG emissions. Additionally, the use of methane for electricity production also generates the least GHG emissions per MWh. This is </span><span style="font-family:Verdana;">approximately</span><span style="font-family:Verdana;"> 3 times lower than crude oil, 4 times lower than black coal </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> 5 times lower than brown coal. However, the adoption and implementation of anaerobic digestion technology in Australia face several immediate constraints. Firstly, anaerobic digestion technology is deemed unprofitable, incurring </span><span style="font-family:Verdana;">high</span><span style="font-family:Verdana;"> initial capital cost, operating costs </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> extremely long payback periods. Secondly, there is a lack of government support in terms of a national target for biogas production via anaerobic digestion. This review will provide an in-depth analysis </span><span style="font-family:Verdana;">into</span><span style="font-family:Verdana;"> the current state of the Australian biogas sector. </span><span style="font-family:Verdana;">In addition</span><span style="font-family:Verdana;">, the review discusses the opportunities to make anaerobic digestion technology more financially viable and to accelerate the growth of the Australian biogas sector.
基金financial support from the National Natural Science Foundation of China (21677046)the Natural Science Foundation of Hebei Province (B2017205146)
文摘Biogas can be used as an alternative energy source for producing heat and electricity;however, volatile methylsiloxanes(VOSiC) present in biogas can severely damage heat exchangers, turbines and gas engines. Consequently, e cient removal of VOSiC from biogas that is used as a biofuel is required. In this work, acetylated silica gel(Ac@SG) was synthesized,via treatment of microporous silica gel(SG) with acetic anhydride as an adsorbent, for removal of VOSiC from biogas,and characterized with XRD, SEM–EDS, N2-BET and FT-IR. This Ac@SG adsorbent exhibited a meso-/microporous structure and hydrophobic surface, indicating it was a more e cient adsorbent for removing hexamethyldisiloxane(L2) and octamethylcyclotetrasiloxane(D4) from biogas samples than conventional SG. It was found that the adsorption capacities of Ac@SG reached 304 mg L2/g for hexamethyldisiloxane and 916 mg D4/g for octamethylcyclotetrasiloxane at lower temperatures in the experimental range, and water had no significant e ect on its absorption e ciency. The used Ac@SG could be easily regenerated by heating it at 110 °C, and the adsorption capacity of recycled Ac@SG for hexamethyldisiloxane and octamethylcyclotetrasiloxane was kept constant in four recycle adsorption experiments.
基金supported by the National Natural Science Foundation of China(22038012,42077030)the Science and Technology Program of Fujian Province,China(2020NZ012015,2020Y4002)the Fundamental Research Funds for the Central Universities of China(20720190001)。
文摘Massive amounts of biogas slurry are produced due to the development of biogas plants.The pollution features and the risk of biogas slurry were fully evaluated in this work.Thirty-one biogas slurry samples were collected from sixteen different cities and five different raw materials biogas plants(e.g.cattle manure,swine manure,straw-manure mixture,kitchen waste and chicken manure).The chemical oxygen demand(COD),ammonia nitrogen(NH_(4)^(+)-N),anions(e.g.Cl^(-1),SO_(4)^(2-),NO_(3)^(-)and PO_(4)^(3-)),antibiotics(e.g.sulphonamides,quinolones,β2-receptor agonists,macrolides,tetracyclines and crystal violet)and heavy metals(e.g.Cu,Cd,As,Cr,Hg,Zn and Pb)contents from these biogas slurry samples were systematically investigated.On this basis,risk assessment of biogas slurry was also performed.The concentrations of COD,NH_(4)^(+)-N and PO_(4)^(3-) in biogas slurry samples with chicken manure as raw material were significantly higher than those of other raw materials.Therefore,the biogas slurry from chicken manure raw material demonstrated the most serious eutrophication threat.The antibiotic contents in biogas slurry samples from swine manure were the highest among five raw materials,mostly sulphonamides,quinolones and tetracyclines.Biogas slurry revealed particularly serious arsenic contamination and moderate potential ecological risk.The quadratic polynomial stepwise regression model can quantitatively describe the correlation among NH_(4)^(+)-N,PO_(4)^(3+) and heavy metals concentration of biogas slurry.This work demonstrated a universal potential threat from biogas slurry that can provide supporting data and theoretical basis for harmless treatment and reuse of biogas slurry.
文摘[C_8min] BF_4 was used in this work to combine with TBAB or THF for the investigation about thermodynamic and kinetic additives on CO_2 and CH_4/CO_2 hydrates. The results show that [C_8min] BF_4 has the inhibition effect on the equilibrium of hydrate formation. About the kinetic study, [C_8 min] BF_4 could improve the rate of CO_2 hydrate formation and increase the gas uptake in hydrate phase. At the same time, the combination of TBAB and [C8 min] BF_4 could increase the mole friction of CH_4 in residual gas comparing with the data in THF solution. CH_4 separation efficiency was strongly enhanced. Since that the size of CO_2 and CH_4 molecules are similar, CH_4 and CO_2 could form the similar hydrate, so the recovery of CH_4 from biogas decreases lightly. The CH_4 content in biogas can purified from 67 mol% to 77 mol% after one-stage hydrate formation. In addition, the combination of THF and[C_8 min] BF_4 do not have obvious promoting effect on CH_4 separation comparing with the gas separation results in pure THF solution.
基金the fund supports from the National Natural Science Foundation of China(21808010).
文摘This study investigated the effects of soluble chemical oxygen demand(s COD),volatile fatty acids(VFAs),and microbial community on biogas production in the process of rice straw(RS)anaerobic digestion(AD).The results showed that the s COD concentrations and VFA production appeared the same trend,which was inversely related with that of daily biogas production.The cumulative methane yield of RS was 194.9 ml·(g VS)^-1·^-1.The modified Gompertz model is the best fit for measured methane yields of RS in the three kinetic models of first-order kinetic,Cone and modified Gompertz.Firmicutes,Bacteroidetes,and Euryarchaeota were the dominant microbial phyla throughout AD process.At the genus level,the microorganisms mainly composed of Clostridium,Vadin,Terrisporobacter,Methanosaeta,Methanobacterium,and Methanosarcina.Proteiniphilum showed strong relationship with s COD and VFA production.Clostridium and Terrisporobacter displayed relationship with biogas production.Therefore,in order to improve the stability of the AD system,the parameter changes of VFAs,s COD,and biogas yield were monitored in the RS AD process.The study can provide theoretical basis for improving the efficiency of RS AD.
基金supported by the National Natural Science Foundation of China (Grant No.71171102)
文摘This paper discusses the history and present status of different categories of biogas production in China,most of which are classified into rural household production,agriculture-based engineering production,and industry-based engineering production.To evaluate the future biogas production of China,five models including the Hubbert model,the Weibull model,the generalized Weng model,the H-C-Z model,and the Grey model are applied to analyze and forecast the biogas production of each province and the entire country.It is proved that those models which originated from oil research can also be applied to other energy sources.The simulation results reveal that China's total biogas production is unlikely to keep on a fast-growing trend in the next few years,mainly due to a recent decrease in rural household production,and this greatly differs from the previous goal set by the official department.In addition,China's biogas production will present a more uneven pattern among regions in the future.This paper will give preliminary explanation for the regional difference of the three biogas sectors and propose some recommendations for instituting corresponding policies and strategies to promote the development of the biogas industry in China.
基金supported by the National Natural Science Funds(71261018,71171208,71473285)
文摘Feedback supply chain is a key structure in the supply chain system, and the development of feedback supply chain for biogas biomass energy is one of the important ways of the rural ecological civilization construction. Presently, the efficiency problem of biogas supply chain in rural China has been restricting the development of biogas biomass energy business. This article, on the basis of combination of regulation parameters, describes the dynamic changes in the system, using differential equations integrated with simulation to reveal the rules of regulation parameters to investigate the efficiency problem in the biogas supply chain. First of all, on the basis of the actual situation, the flow level and flow rate system structure model and simulation equation set are established for the biogas energy feedback supply chain from a scale livestock farm to peasant households; On the basis of the differentiability of the simulation equation a third order inhomogeneous differential equation with constant coefficients containing regulative parameters is established for the quantity of biogas stored in the feedback supply chain. A theorem and its corollaries are established for the operating efficiency of supply chain to reveal the change law of the quantity of biogas,the quantity of biogas consumed daily by peasant households and its standard-reaching rate as well as other variables.
基金Supported by Key Scientific Research Projects of Sichuan Provincial Department of Technology (2010JY0165)Key Special Scientific Research Projects of Mianyang City of Sichuan Province (09Y003-13)Key Scientific Research Projects of Sichuan Provincial Department of Education (2003A112)
文摘The feasibility of adopting a balanced energy mix mode (domestic solar energy, biogas, coal-fired boiler and radiant floor heating) was proposed. Taking a typical rural residence in Zhengzhou City for example, the study through theoretical analysis and calculation showed that such a balanced energy mix is an economic way and efficient in saving energy and reducing air pollution, and elaborated the theoretical feasibility of popularizing such a heat supply mode in rural areas.
基金Supported by National Key Technology R&D Program(2015BAD-21B04)
文摘The possibility of anaerobic digestion of high oil waste at high temperatures was explored,and the effects of fat concentration on biogas production via anaerobic digestion were analyzed by batch and continuous experiments successively. Besides,the response and recovery of the digestion system to the shock of high concentrations of oil were studied. The results showed that the anaerobic digestion of high oil waste could be carried out,and fat concentration had a significant effect on the anaerobic digestion. In the batch experiments,the process of anaerobic digestion could carry out only when fat concentration was 0-1. 68%,and the average methane content was 46. 42%; with the increase of fat concentration,both methane content and production rate decreased significantly,and the digestion period was extended obviously. When fat concentration exceeded 2. 52%,the anaerobic digestion failed to start,and methane could not be detected in the produced biogas. In the continuous experiments,the system could withstand a certain concentration of fat( 6 g/L),and anaerobic digestion process would be inhibited when it experienced the impact of a high oil load( 26. 7 g/L). Nevertheless,this process could recover quickly after the removal of the impact,and the system could withstand a higher fat concentration( 13 g/L) than before. Furthermore,the volume production rate of biogas was approximately 1 L/( L·d),and methane content was about 55%.
文摘The application of organic soil amendments is a common practice for increasing soil fertility and soil organic carbon (SOC) content. In recent years, a new product from biogas production, biogas slurry is increasingly applied to agricultural soils, although little is known about its effects on soil properties. In this study, the influence of this new product in comparison with liquid manure and sewage sludge on the organic carbon dynamics and enzyme activities were investigated in two different agricultural soils in short-term incubation studies. As a control, biologically inert sand was also amended with these organic wastes. In sand, biogas slurry degraded to 10.4% within 14 days, while no differences were found between the degradability of liquid manure and sewage sludge with 6.6% and 5.4%, respectively. However, although the degradability of biogas slurry was highest among the organic amendments, liquid manure application resulted in the highest respiration rates in the soil samples. This was likely due to the organic waste borne easily decomposable substrates which were most dominant in liquid manure. Organic waste applications were found to generally increase the activity of numerous enzymes but did not change the soil enzyme patterns. Thus, in general it was shown that the microbial population of the organic wastes will not become prominent when introduced with the manures to soils. Thus, an inoculation with organic waste borne microorganisms could likely be neglected when discussing the extent of organic carbon dynamics after organic waste application to agricultural soils.
文摘Water hyacinth, E. crassipes, an invasive water weed thrives in fresh water bodies causing serious environmental problems. In Kenya the weed has invaded Lake Victoria and poses great socioeconomic and environmental challenges. Currently the weed is harvested from the Lake and left in the open to rot and decay leading to loss of aesthetics, land and air pollution. There is therefore need for development of value addition and economic exploitation strategies. The aim of the study is to assess the potential for utilization of the weed as a renewable energy resource for biogas production. Samples were collected from Lake Victoria, pulped and blend with cow dung at a ratio of 3:1 as inoculum. The resultant mixture was mixed with water at a ratio of 1:1 and fed into a 6 m3 tubular digester. The digester was recharged with 20 kg after every three days. The temperature, pH variations, gas compositions, upgrading and gas yields were studied. The temperature ranged between 22.8°C - 36.6°C and pH 7.4 - 8.5. Biogas was found to contain 49% - 53% methane (CH4 ), 30% - 33% carbon dioxide (CO2 ), 5% - 6% nitrogen (N2 ) and traces of hydrogen sulphide (H2S). The biogas was upgraded using solid adsorbents and wet scrubbers increasing the methane content by up to 70% - 76%. The upgraded gas was used to power internal combustion engines coupled with an electricity generator and direct heat applications. The study concludes that E. crassipes is a potential feedstock for biogas production especially in areas where it is abundant.
文摘Glycyrrhiza glabra,Mint,Cuminum cyminum,Lavender and Arctium medicinal are considered as edible plants with therapeutic properties and as medicinal plants in Iran.After extraction process of medicinal plants,residual wastes are not suitable for animal feed and are considered as waste and as an environmental threat.At present there is no proper management of waste of these plants and they are burned or buried.The present study discusses the possibility of biogas production from Glycyrrhiza Glabra Waste(GGW),Mentha Waste(MW),Cuminum Cyminum Waste(CCW),Lavender Waste(LW)and Arctium Waste(AW).250 g of these plants with TS of 10%were digested in the batch type reactors at the temperature of 35℃.The highest biogas production rate were observed to be 13611 mL and 13471 mL for CCW and GGW(10%TS),respectively.While the maximum methane was related to GGW with a value of 9041 mL(10%TS).The highest specific biogas and methane production were related to CCW with value of 247.4 mL.(g.VS)-1 and 65.1 mL.(g.VS)-1,respectively.As an important result,it was obvious that in lignocellulose materials,it cannot be concluded that the materials with similar ratio of C/N has the similar digestion and biogas production ability.
