共查询到18条相似文献,搜索用时 62 毫秒
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为了缓解全球能源危机和解决环境污染问题,将农业秸秆类生物质,通过微生物发酵将它们转化为能源及高附加值的化学品,具有重要意义。介绍农业秸秆类生物质的结构成分;综合评述物理和化学预处理方法;重点介绍由农业秸秆类生物质生产乙醇、丁醇的研究现状。指出农业秸秆发酵制取生物燃料工业化进程的关键所在。 相似文献
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生物基(正)丁醇是一种重要的化学品和替代燃料,其主要制备途径为糖质底物的丙酮-丁醇-乙醇(ABE)发酵。受制于发酵副产物多、溶剂浓度低、产物共沸等因素,传统的生物丁醇分离过程存在分离能耗大、成本高等问题,制约其产业化制备。为解决生物丁醇分离的技术瓶颈,近年来,应用新型分离技术实现与ABE发酵过程的耦合成为研究的热点。本文综述了生物丁醇分离技术的最新研究进展,讨论了基于汽液平衡、相转移、膜分离技术等新型分离方式的技术特点;并针对多级分离级联系统开发、面向终产物的精馏技术的新趋势、新特点进行剖析和讨论。随着分离技术的发展和进步、生物炼制工艺开发和集成,生物丁醇的制备成本可望进一步降低,提升市场竞争力。 相似文献
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生物转化植物纤维产酒精的研究进展 总被引:3,自引:0,他引:3
植物纤维是潜在的可再生资源,利用微生物对其进行降解、转化以实现工业化低成本生产,已成为研究的热点。从生物方法角度对植物纤维为原料产酒精的3个阶段:原料预处理、纤维素酶糖化和发酵进行全面的阐述,包括微生物及其作用机理和处理工艺等方面的内容。 相似文献
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Julio Rodríguez‐López Antonio José Sánchez Diana María Gómez Aloia Romaní Juan Carlos Parajó 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2012,87(7):1036-1040
Fumaric acid (FA) was produced from Eucalyptus globulus wood by successive steps of hydrothermal processing (to solubilize hemicelluloses and to increase the susceptibility of solids to enzymatic hydrolysis), enzymatic hydrolysis and fermentation with Rhizopus arrhizus DSM 5772. For comparative purposes, additional fermentations were carried out using synthetic media. Single stage fermentation of synthetic media led to a medium containing 11.8 g FA L?1 (YP/S = 0.60 g g?1). Operating in fed batch mode, the fourth stage increased the FA concentration from 19.7 up to 43.6 g L?1 (YP/S = 0.71 g g?1). Hydrolyzate fermentation in a single stage resulted in lower fumaric acid concentration (9.65 g L?1) and yield (0.35 g g?1). Additional fermentations were carried out in media made with hydrolyzates subjected to membrane processing, adsorption or ion exchange. The highest yield (YP/S = 0.44 g g?1) was reached in media made up of ion‐exchange treated hydrolyzates and a commercial glucose solution in proportion 85/15 w/w. Copyright © 2011 Society of Chemical Industry 相似文献
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Some of the most recent, relevant, industrial and academic contributions made in the field of butanol production are reviewed here. The focus on butanol is due to the growing demand for non‐fossil biofuels. In addition, butanol can be mixed with fossil fuels or can be used alone, allowing an alternative to gasoline. Butanol can be synthesised biologically using sugars extracted from biomass such as agricultural waste. This agricultural waste must be pretreated before it is suitable for sugar extraction. Following this stage, enzymatic hydrolysis is employed, before performing fermentation using microorganisms. This article summarises some of the economical methods such as simultaneous saccharification and fermentation (SSF). Different pretreatment and saccharification processes were compared. Acid pretreatment and saccharification achieved the highest sugar concentrations from wheat straw. Monoethanolamine pretreatment achieved highest sugars from hardwood. Comparisons and analysis of different types of fermentation processes illustrated that immobilised reactor provided the best butanol rate of production. Integration of fermentation with product removal process improved butanol production in immobilised reactor. Gas stripping method was illustrated to be the product removal process. © 2011 Canadian Society for Chemical Engineering 相似文献
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Rocio Sierra Mark T. Holtzapple Cesar B. Granda 《American Institute of Chemical Engineers》2011,57(5):1320-1328
Long‐term lime pretreatment has proven to increase digestibility of many herbaceous lignocellulose sources; but until this work, its effects had not been evaluated on wood, whose lignin content is higher, and therefore, more recalcitrant to enzymatic hydrolysis. In this study, the mild conditions of long‐term lime pretreatment (1‐atm pressure, temperatures ranging from 25 to 75°C, and reaction times between 1 and 12 weeks, with and without air) were systematically applied to poplar wood available in two batches with different lignin contents. These batches were designated as low‐lignin biomass (LLB) with lignin content of 21.4% and high‐lignin biomass (HLB) with lignin content of 29.1%. Full factorial designs resulted in 79 samples of pretreated poplar that were analyzed for lignin and carbohydrates pretreatment yields, and enzymatic digestibility (15 FPU/g glucan in raw biomass cellulose loading). After aerated lime pretreatment at 65°C for 4 weeks, and subsequent enzymatic hydrolysis, an overall yield of 0.76 g glucan + xylan recovered per gram glucan + xylan in raw biomass was obtained. This is equivalent to an increased poplar wood digestibility of 7.5‐fold compared with untreated biomass. Different batches of the feedstock resulted in different lignin and carbohydrates pretreatment yields; however, overall yields of carbohydrates (combining pretreatment and enzymatic hydrolysis) were similar. © 2010 American Institute of Chemical Engineers AIChE J, 2011 相似文献
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以纤维素为原料生产燃料乙醇,由于其原料来源广泛及环保效益良好而被认为是最有前景的生产燃料乙醇的方法之一。在阐述我国发展纤维素乙醇必要性的基础上,综述了纤维素乙醇的浓酸水解、稀酸水解、酶水解及生物质合成气等发酵工艺及研究进展。分析了各工艺优缺点,并讨论了各工艺过程需要解决的关键技术问题,展望了纤维素乙醇的产业化前景。 相似文献
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生物质转化制糠醛工艺的研究进展 总被引:1,自引:0,他引:1
糠醛是目前只能由生物质转化而得到的重要的有机化工原料,是一种可再生、绿色的化工产品,被广泛应用于化工、医药等领域。本文归纳了生物质水解液化及高温分解制备糠醛研究中的关键问题,综述了生物质水解液化一步法、两步法转化制糠醛的催化剂发展及两种工艺的研究进展。一步法生产工艺及技术从最初的单锅蒸煮,发展到多锅串联以及连续生产工艺。两步法研究较为普遍,在新型催化剂、糠醛提取方式、糠醛收率方面都有很大突破。讨论了水解液化与高温分解过程的主要影响因素、机理以及各自的优缺点,从生物质原料处理的工序上比较糠醛的收率。并在此基础上,对生物质转化制糠醛的研究前景进行了展望,指出影响其发展的关键因素在于催化剂的开发,开发出环境友好、经济有效的催化剂是重中之重。 相似文献
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随着传统化石能源日趋枯竭,木质纤维素生物质等可再生资源的综合利用得到越来越多的关注。为了更好地利用木质纤维素生物质,采用物理、化学或生物方法降低其结构顽抗性是必不可少的步骤。在前期研究中,本文作者所在实验室发现了一种乙胺盐酸盐为氢键受体、乳酸为氢键供体的新型低共熔溶剂(EaCl∶LAC),其对玉米芯有很好的去除半纤维素的作用。本文将EaCl∶LAC用于预处理水稻秸秆,并结合碱性氧化剂NaClO,进一步提高了木质素的去除率。在最优条件下,经EaCl∶LAC/NaClO预处理后水稻秸秆的半纤维素和木质素的去除率分别为94.9%和80.2%。将预处理后水稻稻秆经纤维素酶解可得到总还原糖浓度为60.46g/L的秸秆水解液。采用梭菌Clostridium saccharobutylicum DSM13864利用稻秆水解液进行丁醇发酵,72h后丁醇浓度为10.16g/L,丁醇的糖醇产率为0.22g/gtotal sugar。本文提供了一种提高木质纤维素生物质酶解效率和水解液还原糖浓度的方法,无需外源添加葡萄糖和脱毒处理,可直接用于发酵合成生物丁醇。 相似文献
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Adriano Pinto Mariano Caliane Bastos Borba Costa Dejanira de Franceschi de Angelis Francisco Maugeri Filho Daniel Ibraim Pires Atala Maria Regina Wolf Maciel Rubens Maciel Filho 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2010,85(7):934-949
BACKGROUND: The performance of three particle swarm optimisation (PSO) algorithms was assessed in relation to their capability to optimise an alternative fermentation process for the production of biobutanol. The process consists of three interconnected units: fermentor, cell retention system and vacuum flash vessel (responsible for the continuous recovery of butanol from the broth). The dynamic behaviour of the process was described by a non‐linear mathematical model. Four constrained optimisation problems were formulated concerning the operation and design of flash fermentation: (1) maximisation of butanol productivity; (2) maximisation of substrate conversion; (3) and (4) adjustment of operating conditions in the face of problems of fluctuations in the quality of the agricultural raw material and changes in the kinetics of the microorganisms. RESULTS: The design and operation of the flash fermentation process based on the optimisation of productivity, instead of substrate conversion, resulted in a smaller fermentor and provided satisfactory values of operating conditions able to overcome problems of variations in the glucose concentration in the raw material and changes in kinetics. CONCLUSIONS: The differences among the PSO algorithms, i.e. the velocity equation and parameters values, had significant effects on the optimisation, the best results being obtained with the original velocity equation with the inertia weight decreasing linearly with each iteration. The PSO algorithms obtained solutions that obeyed constraints, demonstrating that a constraint handling method originally developed for genetic algorithms can be applied successfully to PSO algorithms. Copyright © 2010 Society of Chemical Industry 相似文献