Reducing CO_(2) to produce methane through microbial electrolytic cell(MEC)is one of the important methods of CO_(2) resource utilization.In view of the problem of low methanogenesis rate and weak CO_(2) conversion ra...Reducing CO_(2) to produce methane through microbial electrolytic cell(MEC)is one of the important methods of CO_(2) resource utilization.In view of the problem of low methanogenesis rate and weak CO_(2) conversion rate in the reduction process,theflowfield environment of the cathode chamber is changed by changing the upper gas cir-culation rate and the lower liquid circulation rate of the cathode chamber to explore the impact on the reactor startup and operation and products.The results showed that under certain conditions,the CO_(2) consumption and methane production rate could be increased by changing the upper gas recirculation rate alone,but the increase effect was not obvious,but the by-product hydrogen production decreased significantly.Changing the lower liquid circulation rate alone can effectively promote the growth of biofilm,and change the properties of biofilm at the later stage of the experiment,with the peak current density increased by 16%;The methanogenic rate decreased from the peak value of 0.561 to 0.3 mmol/d,and the CO_(2) consumption did not change signifi-cantly,which indicated that CO_(2) was converted into other organic substances instead of methane.The data after coupling the upper gas circulation rate with the lower liquid circulation rate is similar to that of only changing the lower liquid circulation rate,but changing the upper gas circulation rate can alleviate the decline of methane pro-duction rate caused by the change of biofilm properties,which not only improves the current density,but also increases the methane production rate by 0.05 mmol/d in the stable period.This study can provide theoretical and technical support for the industrial application scenario offlowfield regulation intervention of microbial elec-trolytic cell methanogenesis.展开更多
Mesophilic biogas production and substrate decomposition is one of the significant limiting steps in biogas generation. The rate of generation and quality often affect the viability of biogas systems. This study asses...Mesophilic biogas production and substrate decomposition is one of the significant limiting steps in biogas generation. The rate of generation and quality often affect the viability of biogas systems. This study assessed the potential for biogas process catalysis using powdered Sorghum bicolor L., Zea mays, and Pennisetum glaucum. The kinetics and biogas generation processes were studied. Experiments were conducted in 1 m<sup>3</sup> tubular batch reactors, where batches were dosed with various organic biomolecules. Results show that the use of P. glaucum L. and S. bicolor L. reduced the biogas retention times significantly. Biogas generation commenced after the first day for digesters fed with S. bicolor L. and P. glaucum L. while one with Z. mays and control occurred on day two. The rate of biomethanation and methane content were enhanced. S. bicolor L. led to the highest methane content. Findings reveal that locally available organic biomolecules improved biogas quality and quantity.展开更多
Brazil is the world’s largest producer and consumer of passion fruit,being a tropical fruit that produces a lot of waste in its process.As this residue is more than 60%of the mass of the fruit,there is a problem dire...Brazil is the world’s largest producer and consumer of passion fruit,being a tropical fruit that produces a lot of waste in its process.As this residue is more than 60%of the mass of the fruit,there is a problem directed to the discard of the same.One way to add economic and financial value to the passion fruit industry would be to use the waste as a source of fuel in a process of converting biomass to energy.The objective of this work was to characterize samples of passion fruit residues by analyzing the moisture content and the experimental calorific value,aiming at its energy utilization,in order to obtain initial information to help define the best conversion path of this biomass:thermochemical or biochemical.After analysis,it was concluded that the most appropriate biomass utilization route would be anaerobic biodigestion due to the high moisture content presented in the samples(greater than 80%).However,the same ones,if in dry basis,also have high calorific value,compared,for example,with sugarcane bagasse.With the results,it was demonstrated that the biomass of the passion fruit pulp presents itself as a potential alternative for the energy utilization.展开更多
碳捕获和封存路线(carbon capture and storage,简称CCS)和生物甲烷路线是实现二氧化碳减排的两种重要途径。但CCS路线存在捕集成本高的难题,而生物甲烷路线规模小、尚处于起步阶段。本文从经济和技术角度对比了两种路线减排二氧化碳的...碳捕获和封存路线(carbon capture and storage,简称CCS)和生物甲烷路线是实现二氧化碳减排的两种重要途径。但CCS路线存在捕集成本高的难题,而生物甲烷路线规模小、尚处于起步阶段。本文从经济和技术角度对比了两种路线减排二氧化碳的优缺点,发现生物甲烷路线理论捕集能耗仅为CCS路线的一半,且捕集条件温和,更有利于提高吸附剂材料的容量、降低捕集成本,因而生物甲烷路线更具有减排潜力。为了解决CCS和生物甲烷路线目前存在的困境,提出了CCS与生物甲烷耦合、借助CCS加速发展生物甲烷过程的新思路。展开更多
Wheat straw biodegradability during anaerobic digestion was improved by treatment with potassium hydroxide （KOH） to decrease digestion time and enhance biomethane production and fertility value. KOH concentrations o...Wheat straw biodegradability during anaerobic digestion was improved by treatment with potassium hydroxide （KOH） to decrease digestion time and enhance biomethane production and fertility value. KOH concentrations of 1% （KI）, 3% （[（2）, 6% （K3） and 9% （l（4） were tested for wheat straw pretreatment at ambient temperature with a C：N ratio of 25：1.86% of total solids （TS）, 89% of volatile solids （VS） and 22% of lignocellulose, cellulose and hemi- cellulose （LCH） （22%） were decomposed effectively with the wheat straw pretreated by 6% KOH. Enhanced bio- gas production and cumulative biomethane yield of 258 ml. （g VS）-1 were obtained increased by 45% and 41% respectively, compared with untreated wheat straw. Pretreated wheat straw digestion also yielded a digestate with higher fertilizer values potassium （l 38%）, calcium （22%） and magnesium （16%）. These results show that TS, VS and LCH can be effectively removed from wheat straw pretreated with KOH, improving biodegradability biomethane production and fertilizer value.展开更多
基金This paper is supported by Shanghai Science and Technology Development Fund,China,No.19DZ1205604.
文摘Reducing CO_(2) to produce methane through microbial electrolytic cell(MEC)is one of the important methods of CO_(2) resource utilization.In view of the problem of low methanogenesis rate and weak CO_(2) conversion rate in the reduction process,theflowfield environment of the cathode chamber is changed by changing the upper gas cir-culation rate and the lower liquid circulation rate of the cathode chamber to explore the impact on the reactor startup and operation and products.The results showed that under certain conditions,the CO_(2) consumption and methane production rate could be increased by changing the upper gas recirculation rate alone,but the increase effect was not obvious,but the by-product hydrogen production decreased significantly.Changing the lower liquid circulation rate alone can effectively promote the growth of biofilm,and change the properties of biofilm at the later stage of the experiment,with the peak current density increased by 16%;The methanogenic rate decreased from the peak value of 0.561 to 0.3 mmol/d,and the CO_(2) consumption did not change signifi-cantly,which indicated that CO_(2) was converted into other organic substances instead of methane.The data after coupling the upper gas circulation rate with the lower liquid circulation rate is similar to that of only changing the lower liquid circulation rate,but changing the upper gas circulation rate can alleviate the decline of methane pro-duction rate caused by the change of biofilm properties,which not only improves the current density,but also increases the methane production rate by 0.05 mmol/d in the stable period.This study can provide theoretical and technical support for the industrial application scenario offlowfield regulation intervention of microbial elec-trolytic cell methanogenesis.
文摘Mesophilic biogas production and substrate decomposition is one of the significant limiting steps in biogas generation. The rate of generation and quality often affect the viability of biogas systems. This study assessed the potential for biogas process catalysis using powdered Sorghum bicolor L., Zea mays, and Pennisetum glaucum. The kinetics and biogas generation processes were studied. Experiments were conducted in 1 m<sup>3</sup> tubular batch reactors, where batches were dosed with various organic biomolecules. Results show that the use of P. glaucum L. and S. bicolor L. reduced the biogas retention times significantly. Biogas generation commenced after the first day for digesters fed with S. bicolor L. and P. glaucum L. while one with Z. mays and control occurred on day two. The rate of biomethanation and methane content were enhanced. S. bicolor L. led to the highest methane content. Findings reveal that locally available organic biomolecules improved biogas quality and quantity.
文摘Brazil is the world’s largest producer and consumer of passion fruit,being a tropical fruit that produces a lot of waste in its process.As this residue is more than 60%of the mass of the fruit,there is a problem directed to the discard of the same.One way to add economic and financial value to the passion fruit industry would be to use the waste as a source of fuel in a process of converting biomass to energy.The objective of this work was to characterize samples of passion fruit residues by analyzing the moisture content and the experimental calorific value,aiming at its energy utilization,in order to obtain initial information to help define the best conversion path of this biomass:thermochemical or biochemical.After analysis,it was concluded that the most appropriate biomass utilization route would be anaerobic biodigestion due to the high moisture content presented in the samples(greater than 80%).However,the same ones,if in dry basis,also have high calorific value,compared,for example,with sugarcane bagasse.With the results,it was demonstrated that the biomass of the passion fruit pulp presents itself as a potential alternative for the energy utilization.
文摘碳捕获和封存路线(carbon capture and storage,简称CCS)和生物甲烷路线是实现二氧化碳减排的两种重要途径。但CCS路线存在捕集成本高的难题,而生物甲烷路线规模小、尚处于起步阶段。本文从经济和技术角度对比了两种路线减排二氧化碳的优缺点,发现生物甲烷路线理论捕集能耗仅为CCS路线的一半,且捕集条件温和,更有利于提高吸附剂材料的容量、降低捕集成本,因而生物甲烷路线更具有减排潜力。为了解决CCS和生物甲烷路线目前存在的困境,提出了CCS与生物甲烷耦合、借助CCS加速发展生物甲烷过程的新思路。
基金Supported by Specialized Research Fund for the Doctoral Program of Higer Education(20120010110004)the Natural Science Foundation of Beijing(8142030)
文摘Wheat straw biodegradability during anaerobic digestion was improved by treatment with potassium hydroxide （KOH） to decrease digestion time and enhance biomethane production and fertility value. KOH concentrations of 1% （KI）, 3% （[（2）, 6% （K3） and 9% （l（4） were tested for wheat straw pretreatment at ambient temperature with a C：N ratio of 25：1.86% of total solids （TS）, 89% of volatile solids （VS） and 22% of lignocellulose, cellulose and hemi- cellulose （LCH） （22%） were decomposed effectively with the wheat straw pretreated by 6% KOH. Enhanced bio- gas production and cumulative biomethane yield of 258 ml. （g VS）-1 were obtained increased by 45% and 41% respectively, compared with untreated wheat straw. Pretreated wheat straw digestion also yielded a digestate with higher fertilizer values potassium （l 38%）, calcium （22%） and magnesium （16%）. These results show that TS, VS and LCH can be effectively removed from wheat straw pretreated with KOH, improving biodegradability biomethane production and fertilizer value.
