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121.
Thermochemical processing of meat and bone meal: A review 总被引:1,自引:0,他引:1
Since the Bovine Spongiform Encephalopathy crisis, meat and bone meal (MBM) have been considered animal wastes. Nowadays, these animal residues are generally burnt in cement kilns and disposed of in landfills. However, several technologies are being developed in order to achieve energy valorisation of MBM by means of combustion, pyrolysis and gasification. These thermal treatments of MBM will reduce the environmental impact of landfill and, at the same time, take advantage of the MBM heating value (13-30 MJ/kg). The main results of research into combustion, pyrolysis and gasification of MBM show that the products could be used as fertilizer (solid product) and as fuel (gas and liquid products). The present work aims at reviewing the most significant studies about energy valorisation of MBM and the potential application of the products obtained in these thermochemical processes. 相似文献
122.
Empty fruit bunch (EFB) from oil palm is one of the potential biomass to produce biofuels like bio-oil due to its abundant supply and favorable physicochemical characteristics. Confirming the assertion, this paper presents an overview of EFB as a feedstock for bio-oil production. The fundamental characteristics of EFB in terms of proximate analysis, ultimate analysis and chemical composition, as well as the recent advances in EFB conversion processes for bio-oil production like pyrolysis and solvolysis are outlined and discussed. A comparison of properties in terms of proximate analysis, ultimate analysis and fuel properties between the bio-oil from EFB and petroleum fuel oil is included. The major challenges and future prospects towards the utilization of EFB as a useful resource for bio-oil production are also addressed. 相似文献
123.
This study investigated the reduction of primary tar vapor from biomass pyrolysis over a bed of hot char particles, focusing on the effect of different operating conditions and char properties. The char samples were prepared from wood, paddy straw, palm kernel shell, and activated carbon. The primary tar was produced from fir wood by pyrolysis at 500 °C and passed through a reactor filled with char particles with different lengths and temperatures.The tar cracking reactions became active above 700 °C, and the presence of hot char particles promoted more tar reduction compared with thermal cracking alone. The mass yield of the primary tar was reduced from 24.8% by pyrolysis to 13.7% by thermal cracking at 800 °C, and further to 7.7% by hot char particles in a reactor volume of 1.48 cm3/gwood. In terms of carbon yield, these values correspond to 32.1%, 19.9% and 11.8%, respectively. The tar with smaller molecular weights was quickly decomposed to gases, whereas the heavy tar was resistant to cracking, even when the reactor volume was increased to 6.90 cm3/gwood. The tar cracking behaviors were similar for four char types despite differences in microscopic surface areas, pore-size distributions, and inorganic contents. The results suggest that creating a tar-cracking zone using char particles situated between the pyrolysis and gasification zones could be helpful in converting the primary tar vapor in a downdraft fixed-bed gasifier, but the degree of conversion is not high enough to eliminate tar issues completely. 相似文献
124.
介绍中化弘润石油化工有限公司600 kt/a催化汽油加氢装置加氢催化剂RSDS-21,RSDS-22首次进行反应器外再生、重生及工业应用情况。经过器外烧炭再生及重生后,RSDS-21中碳质量分数由4.21%下降至0.52%,硫质量分数由5.60%下降至0.51%;RSDS-22中碳质量分数由4.90%下降至0.55%,硫质量分数由5.20%下降至0.84%,重生后催化剂颗粒完整。各项开工数据表明,经过硫化处理后,催化剂活性恢复较好,基本达到装置初次开工时催化剂活性水平,各项产品指标达到国标要求。反应在低温状态下进行,有利于降低产品汽油辛烷值损失,延长催化剂使用寿命。此次催化剂再生、重生效果较好,达到生产要求。 相似文献
125.
Biochar composition and stability is under intense research. Yet the question remains to what extent the current state-of-the-art applies to artisanally charred biomass in tropical regions. We compared kiln and drum based biochars with their counterpart controlled (at 400 °C) slow pyrolysis biochars from coconut shells, rice husks and Palmyra nutshell for their biochemical composition, thermal stability and biodegradability in soil. Thermal behavior of individual organic constituents was quantified by pyrolysis-field ionization mass spectroscopy (Py-FIMS). Comparison of the mass spectra demonstrated higher abundances of either phenols, lignin and carbohydrate monomers or of lipids in the artisanally produced biochars. Hence, relatively more untransformed plant matter was preserved by artisanal charring and also the thermal stability of carbohydrates, alkylaromatics and N-containing compounds was lower for all three feedstocks. This indicates lower prevailing temperatures compared to controlled pyrolysis biochar, at least in parts of the biomass charring in the kilns or drum. Nine-weeks biochar derived C mineralization upon soil incorporation revealed a relatively lower biological stability of the controlled pyrolysis biochars. The proportion of detected ion intensity from thermolabile lower mass signals (<400 °C, m/z < 250) was negatively correlated to the net-biochar derived C mineralization. We hypothesize this fraction to be composite and act both as a C-substrate and at the same time to hold unidentified substances inhibiting microbial activity. Compared to controlled pyrolysis biochar, traditionally charred biomass, i.e. the ‘biochar’ most likely to be actually applied to soil in developing countries, has a heterogeneous thermal and biochemical composition and unpredictable biological stability. 相似文献
126.
An investigation of the gasoline permeation resistance of the as‐blow‐molded and annealed polyethylene, polyethylene (PE)/polyamide (PA), and polyethylene/modified polyamide (MPA) bottles is reported. The gasoline permeation resistance improves dramatically after blending PA and MPA barrier resins in PE matrices during blow‐molding, and the order of barrier improvement corresponds to the order of barrier improvement of the barrier resins added in PE. Somewhat unexpectedly, the gasoline permeation rates of the annealed PE and/or PE/PA bottles annealed at 90°C or higher temperatures increase significantly with the annealing temperature and time. On the contrary, the gasoline permeation resistance of the annealed PE/MPA bottles increase significantly as the annealing temperature and/or time increase. For instance, the gasoline permeation rate of the PE/MPA bottle annealed at 120°C for 32 h is about 190 times slower than that of the as‐blow‐molded PE bottle. Further investigations found that, after blending the MPA and PA barrier resins in PE matrices, the relatively nonpolar hydrocarbon components present in the gasoline fuels were significantly blocked, without permeation during the permeation tests, in which the as‐blow‐molded PE/MPA bottle inhibited the permeation of hydrocarbon components more successfully than did the as‐blow‐molded PE/PA bottle. In contrast, the amounts of polar components that permeated through the as‐blow‐molded PE/PA and PE/MPA bottles were very small and about the same as the amount that permeated through the as‐blow‐molded PE bottle. Possible mechanisms accounting for these interesting behaviors are proposed in this study. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2827–2837, 2001 相似文献
127.
Char particles from pyrolyzed biomass vary in particle size and shape. On average, the particles are more elongated the larger their size. The average size‐specific elongation is almost alike for all investigated samples, i.e. independent from their source material and process. The particle collectives cannot be characterized accurately with classical particle size distributions, which assume spherical particle shape. Accounting for their shape, they can be described more accurately with particle size distributions that are based on an ellipsoid model. The high bulk porosity is mainly attributed to the spaces between particles. 相似文献
128.
129.
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
130.
采用GC-MS联用技术建立了一种汽油中金属抗爆剂的定性和定量分析方法,测定了汽油中四乙基铅、二茂铁、环戊二烯三羰基锰(CMT)和甲基环戊二烯三羰基锰(MMT)4种金属抗爆剂的含量。根据4种金属抗爆剂的标准质谱谱图和对汽油组分的GC-MS分析,选择了合适的特征定量离子进行选择离子扫描,可有效降低汽油中其他组分对测定结果的干扰。以氘代三联苯为内标物,采用内标法进行定量。实验结果表明,该方法对质量浓度在0.50~50.00 mg/L内的四乙基铅、二茂铁、CMT和MMT均具有良好的线性响应,线性相关系数均达到0.999,且具有很好的准确度和重复性,加标回收率在94.00%~110.00%之间,相对标准偏差均小于3.1%,可满足汽油中金属抗爆剂的测试要求。 相似文献