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41.
This study explores how two different cellulosic ethanol production system configurations (distributed versus centralized processing) affect some aspects of the economic and environmental performance of cellulosic ethanol, measured as minimum ethanol selling price (MESP) and various environmental impact categories. The eco-efficiency indicator, which simultaneously accounts for economic and environmental features, is also calculated. The centralized configuration offers better economic performance for small-scale biorefineries, while the distributed configuration is economically superior for large-scale biorefineries. The MESP of the centralized configuration declines with increased biorefinery size up to a point and then rises due to the cost of trucking biomass to the biorefinery. In contrast, the MESP in the distributed configuration continuously declines with increasing biorefinery size due to the lower costs of railroad transportation and the greater economies of scale achieved at much larger biorefinery sizes, including biorefineries that reach the size of an average oil refinery—about 30,000 tons per day of feedstock. The centralized system yields lower environmental impacts for most impact categories than does the distributed system regardless of the biorefinery size. Eco-efficiency analysis shows that the centralized configuration is more sustainable for small-scale biorefineries, while the distributed configuration with railroad transport is more sustainable for large-scale biorefineries. Compared with gasoline from petroleum, cellulosic ethanol fuel offers sustainability advantages for the following environmental impact categories: fossil energy consumption, global warming, human health impacts by particulate matter, ozone layer depletion, ecotoxicity, human health cancer, and human health non-cancer, depending somewhat on the biorefinery sizes and the system configurations. 相似文献
42.
North American publics are currently much more supportive of second-generation biofuels than of conventional biofuels like corn-based ethanol. But what is the likely future trajectory of consumer acceptance of advanced biofuels? This study considers whether increased awareness of the potential unintended consequences of increasing the production of advanced biofuels could lead to a decline in public support for the technology. Using an experiment embedded in an original survey of Canadian adults, we test for the effect of two anti-biofuels arguments on Canadians' support for policies meant to encourage the production of biofuels. We find that support for biofuels policies was reduced in our experiment when respondents were exposed to an argument about the potential impact of biofuels production on food prices and when they were told that the use of woody biomass as a feedstock for the production of cellulosic biofuels might lead to an increase in commercial logging. In both cases, however, support was reduced only among respondents who did not perceive climate change to pose a significant risk. Overall, our results suggest that public support for advanced biofuels is potentially vulnerable to arguments that focus on the unintended consequences of producing biofuels from non-food feedstocks. 相似文献
43.
The common fermentation of biogenic wastes and sewage sludge in digesters of municipal wastewater treatment plants is a technically feasible and economically viable approach. As the number of rural biogas production sites is steadily increasing, the question has been raised which biomass feedstocks are left available in sufficient quantities to be used for energy generation at wastewater treatment plant level. The contribution of lignocellulosic biomass collected from urban areas is generally neglected within this context. In the present study, 24 urban substrates have been analyzed for their theoretical methane potential, while 13 of them were tested in batch assays for the determination of their practical achievable methane yield. The theoretical evaluation of the methane potential yielded values ranging between 0.393 and 0.576 Nm3 kgVS−1. The methane yields obtained by batch assays showed significantly lower yields, which depends on the individual composition of the substrates in terms of lignin, hemicellulose and cellulose. A GIS spatial analysis for the Rhine-Ruhr metropolitan area was performed to evaluate the feasible capacity of urban biomass as co-fermentation feedstock in digesters of municipal wastewater treatment plants. The analysis revealed that green urban areas provide a significant quantity of biomass of 377 tFM d−1 that could cover 67% of the annual energy demand of twelve typical wastewater treatment plants located in the metropolis. 相似文献
44.
The production of renewable transportation fuel through fed‐batch and continuous deoxygenation of vegetable oil derived fatty acids over Pd/C catalyst 下载免费PDF全文
Renewable fuels such as green diesel from renewable biomass have received attentions because of energy and environmental concerns. Deoxygenation, used to upgrade biomass derived oils has been applied intensively nowadays. To successfully improve this process, fed‐batch and following continuous processes on real biomass derived fatty acids need to be investigated. In this study, liquid‐phase deoxygenation of vegetable oil derived fatty acids was carried out over 5% Pd/C with cofeeding H2. With sufficient hydrogen, complete hydrogenation of unsaturated fatty acids occurred, leading to successive deoxygenation of the saturated fatty acids with n‐alkane yields of 99% and 88% and average CO2 selectivity of 94.9% and 94.6% in the fed‐batch and continuous mode, respectively. After hydrogenation is completed, lower than 5% of effective H2 partial pressure was found to be favorable for the decarboxylation pathway and ideal for deoxygenation of biomass derived fatty acids. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
45.
生物质固体成型燃料因其碳中性、氮硫含量低、烟气污染少、便于运输等优势,在供热、供气以及发电方面可以大量替代煤炭、天然气或重油,在有效供能的同时,能够显著减少污染,实现CO2零排放,符合当前社会可持续发展的理念。尽管我国出台了一系列激励政策,但是在产业发展的过程中还存在一定问题,产业发展离国家目标还有一定差距。本文对目前国内外已出台的生物质成型燃料产业政策进行了归纳和总结,并对我国的关键产业政策,如秸秆能源化补贴政策、税收减免政策、环保措施政策、贷款优惠的执行效果做了跟踪调研,对不同政策的执行力度与成效做了评价和分析,最终给出了政策改进建议。 相似文献
46.
通过灰成分分析、热重-差示扫描量热-傅里叶红外光谱分析联用(TG-DSC-FTIR)试验,对桉树类生物质锅炉燃烧后飞灰可燃物含量的分析方法进行了研究.结果表明:桉树类生物质燃烧后飞灰中含有多种金属化合物,在空气高温加热过程中会同时发生缓慢氧化反应、碳酸盐分解反应、碱金属氯化物的蒸发过程,影响其中可燃物含量的准确测量;灰中可燃物燃烧温度约在350~550℃范围内,采用低浓度硫酸酸洗对灰样进行预处理,可排除碳酸盐分解反应、碱金属及氯元素的蒸发过程对可燃物含量测量的干扰,且以10K/min及以下的低升温速率加热时灰样中化合物不会发生缓慢氧化反应,使灰中可燃物含量测量结果较为准确. 相似文献
47.
48.
应用人工神经网络方法对生物质的热值进行了预测,网络的训练数据集来自美国Biomass Feedstock Composition and Property Database of U.S.Department of Energy。神经网络以生物质的工业分析结果作为输入数据.采用56组数据对网络进行训练,以7组数据对网络进行验证,对网络输出值与实际值进行比较,相对误差在0.08%以内。人工神经网络成功地预测各种生物质的热值,说明人工神经网络能够处理生物质的热值与工业分析各组分间的非线性关系。 相似文献
49.
对生物质焦油进行了馏程试验.采用非等温热重分析法研究了生物质焦油及其馏分的燃烧动力学过程,提出其反应动力学方程。根据试验结果探讨了焦油资源化利用的途径,为焦油的综合利用提供了重要的科学参考依据。 相似文献
50.