共查询到19条相似文献,搜索用时 109 毫秒
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纤维素燃料乙醇已成为下一代燃料乙醇的必然发展方向。文章综述了近年来以木质纤维素为原料生产燃料乙醇的关键技术,重点对物理法、化学法、蒸汽爆破法、生物法等木质纤维素原料预处理技术,酸水解、酶水解等水解(糖化)技术,以及直接发酵法、水解发酵两步法、同步水解发酵法等发酵工艺进行了总结,并指出了未来纤维素乙醇的产业化过程中必须解决的关键问题和发展趋势。 相似文献
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木质纤维原料生物转化燃料乙醇的研究进展 总被引:31,自引:2,他引:31
木质纤维生物量能够用来生产一种可替代有限的石油产品的能源——乙醇。木质纤维的转化主要分两个步骤木质纤维生物量中纤维素水解生成还原糖;糖发酵成乙醇。基于目前的技术,木质纤维原料生产乙醇的主要问题是得率低、水解成本高。促进木质纤维水解的方法包括木质纤维原料预处理脱除木素和半纤维素;纤维素酶的优化;同步糖化发酵法(SSF)。 相似文献
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在分析美国、日本、加拿大等国关于纤维素制取乙醇技术发展的基础上,对木质纤维素原料生产乙醇的预处理及水解为葡萄糖技术和纤维素原料发酵生产酒精生产技术、酒精废糟的处理利用进行了述评与讨论,对木质纤维素原料不同的预处理、水解和发酵方法进行了比较,展望了木质纤维素原料生产燃料酒精的前景. 相似文献
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木质纤维素水解制取燃料乙醇研究进展 总被引:1,自引:1,他引:0
《化工进展》2009,28(11)
以木质纤维素生产燃料乙醇具有原料可再生性和环境友好的优点而备受重视.本文介绍了国内外木质纤维素制取燃料乙醇中的水解工艺过程,包括浓酸水解、稀酸水解和酶水解工艺,分析了各工艺的技术特点,同时指出稀酸预处理-酶水解工艺将成为近几年国内外研究和开发的重点. 相似文献
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以木质纤维素生产燃料乙醇具有原料可再生性和环境友好的优点而备受重视。本文介绍了国内外木质纤维素制取燃料乙醇中的水解工艺过程,包括浓酸水解、稀酸水解和酶水解工艺,分析了各工艺的技术特点,同时指出稀酸预处理-酶水解工艺将成为近几年国内外研究和开发的重点。 相似文献
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近十年来,随着石油价格的上涨以及化石燃料使用对全球变暖的影响,利用木质素纤维素制取燃料乙醇日益成为国内外研究的热点。木质纤维素制取乙醇的主要步骤包括:原料的预处理、纤维素的糖化、发酵、产品分离。木质纤维素的组成包括木质素、半纤维素和纤维素,其中木质素和半纤维素对纤维素的水解具有阻碍作用。因此,在木质纤维素制取乙醇的工艺过程中,原料的预处理是非常关键的步骤,影响整个木质纤维素乙醇的生产过程。文章回顾了木质纤维素原料主要的预处理技术的最新进展,并结合后续的水解与发酵工序,对各种预处理技术的优缺点进行了对比。 相似文献
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从木质纤维素制备燃料乙醇的基本工艺可以分为预处理、 水解、发酵和纯化4个部分。考虑到微生物方法在工业化生产中具有的低成本优势,本文就微生物在预处理中的应用,微生物在纤维素酶生产中的应用以及微生物在乙醇发酵中的应用这三方面的研究现状进行了综述,并进一步分析了在改进原料预处理、提高纤维素酶产量和活性、扩大糖原范围、优化水解发酵工艺等方面的研究进展。 相似文献
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Pretreatment of Lignocellulosic Wastes to Improve Ethanol and Biogas Production: A Review 总被引:3,自引:0,他引:3
Mohammad J. Taherzadeh Keikhosro Karimi 《International journal of molecular sciences》2008,9(9):1621-1651
Lignocelluloses are often a major or sometimes the sole components of different waste streams from various industries, forestry, agriculture and municipalities. Hydrolysis of these materials is the first step for either digestion to biogas (methane) or fermentation to ethanol. However, enzymatic hydrolysis of lignocelluloses with no pretreatment is usually not so effective because of high stability of the materials to enzymatic or bacterial attacks. The present work is dedicated to reviewing the methods that have been studied for pretreatment of lignocellulosic wastes for conversion to ethanol or biogas. Effective parameters in pretreatment of lignocelluloses, such as crystallinity, accessible surface area, and protection by lignin and hemicellulose are described first. Then, several pretreatment methods are discussed and their effects on improvement in ethanol and/or biogas production are described. They include milling, irradiation, microwave, steam explosion, ammonia fiber explosion (AFEX), supercritical CO2 and its explosion, alkaline hydrolysis, liquid hot-water pretreatment, organosolv processes, wet oxidation, ozonolysis, dilute-and concentrated-acid hydrolyses, and biological pretreatments. 相似文献
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Heriberto Franco André Ferraz Adriane M. F. Milagres Walter Carvalho Juanita Freer Jaime Baeza Regis Teixeira Mendonça 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2012,87(5):651-657
BACKGROUND: Alkaline sulfite/anthraquinone (ASA) cooking of Pinus radiata and Pinus caribaea wood chips followed by disk refining was used as a pretreatment for the production of low lignified and high fibrillated pulps. The pulps produced with different delignification degrees and refined at different energy inputs (250, 750 and 1600 Wh) were saccharified with cellulases and fermented to ethanol with Saccharomyces cerevisiae using separated hydrolysis and fermentation (SHF) or semi‐simultaneous saccharification and fermentation (SSSF) processes. RESULTS: Delignification of ASA pulps was between 25% and 50%, with low glucans losses. Pulp yield was from 70 to 78% for pulps of P. radiata and 60% for the pulp of P. caribaea. Pulps obtained after refining were evaluated in assays of enzymatic hydrolysis. Glucans‐to‐glucose conversion varied from 20 to 70%, depending on the degree of delignification and fibrillation of the pulps. The best ASA pulp of P. radiata was used in SHF and SSSF experiments of ethanol production. Such experiments produced maximum ethanol concentration of 20 g L?1, which represented roughly 90% of glucose conversion and an estimated amount of 260 L ethanol ton?1 wood. P. caribaea pulp also presented good performance in the enzymatic hydrolysis and fermentation but, due to the low amount of cellulose present, only 140 L ethanol would be obtained from each ton of wood. CONCLUSION: ASA cooking followed by disk refining was shown to be an efficient pretreatment process, which generated a low lignified and high‐fibrillated substrate that allowed the production of ethanol from the softwoods with high conversion yields. Copyright © 2012 Society of Chemical Industry 相似文献
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玉米芯稀酸预处理和分步糖化与发酵工艺生产燃料乙醇的中试研究 总被引:1,自引:0,他引:1
利用正交试验在中试水平考察了玉米芯的稀硫酸预处理和分步糖化与水解生产乙醇的工艺。结果:最佳预处理工艺为稀硫酸浓度1.1%,温度120℃,固液比1∶8,时间3 h;酶解糖化最佳工艺为:起始底物浓度180 g/L,滤纸酶活:纤维二糖酶活=20 IU/g底物:7 IU/g底物,pH=5.0,48 h;利用运动发酵单胞菌发酵酶解液,35℃,48 h,发酵液中乙醇浓度最高67.8 g/L。 相似文献
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木质纤维素转化燃料乙醇一般需要经过原料预处理、酶水解和发酵过程。由于木质纤维原料化学结构复杂、直接酶解效率非常低,一般在酶水解之前需要进行适当的预处理以打破其致密结构,增加纤维表面积,提高后续纤维素酶的可及性。预处理程度直接影响纤维底物后续酶水解的效果。本文在木质纤维素常用预处理技术分析的基础上,重点讨论了3种相对高效的预处理技术:微波辅助离子液体预处理、两阶段深度共熔溶剂(DES)预处理和氯化铁预处理技术,分析了它们的优势、不足及发展现状。文中指出微波辅助离子液体预处理可有效解构木质素和半纤维素,破坏纤维素结晶区域,利于后续酶解,但微波加热过程会使离子液体分解和部分底物碳化。两阶段DES预处理可有效提高酶水解效率,但是预处理后原料中残留的DES可能会对后续反应中纤维素酶和微生物产生抑制作用。氯化铁预处理可有效破坏木质素与碳水化合物间的结合键,脱除底物中的半纤维素,而对木质素和纤维素降解较少,具有很好的发展前景。由于单一预处理技术的局限性,寻求低成本高效的联合预处理技术将是未来重点发展的方向。 相似文献
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Giada Franceschin Maria SudiroThomas Ingram Irina SmirnovaGerd Brunner Alberto Bertucco 《Chemical Engineering Research and Design》2011,89(6):631-640
A contribution to the development of economically sustainable processes to obtain lignocellulosic bioethanol is presented.The simultaneous production of bioethanol and xylitol from rye straw is investigated, as this compound can become a realistic alternative to the transformation of xylose into ethanol. A complete process from the raw material to the end products is developed and simulated with respect to all major operations: hot liquid water pretreatment, fermentation of glucose to ethanol, fermentation of xylose to xylitol, separation and purification of both products. Calculations are based on experimental as well as on literature data. In particular, experimental data about the pretreatment and enzymatic hydrolysis steps previously obtained (Ingram et al., 2009) are used in order to achieve a realistic model that was then implemented using the software Aspen Plus™. The optimization of the process energy duties is carried out by means of the pinch technology analysis. Mass balances from the simulation are used in order to size the equipments and calculate the capital investment. Finally production costs and some financial indexes are estimated by an economical analysis. 相似文献
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M.P. García-Aparicio 《Fuel》2011,90(4):1624-1630
Barley straw is nowadays being considered a potential lignocellulosic raw material for fuel-ethanol production as an alternative to starch- or sugar-containing feedstock. In this work, several configuration strategies for ethanol production from steam-exploded barley straw by Kluyveromyces marxianus CECT 10875 have been studied with the aim of obtaining higher ethanol concentrations.Different substrate loading (2-15%, w/v) were studied during enzymatic hydrolysis. The xylanase contribution on glucose production and glucan conversion at different substrate loading was also investigated. In addition, three different process configurations, separate hydrolysis and fermentation, simultaneous saccharification and fermentation and presaccharification and simultaneous saccharification, were compared at different water insoluble solids concentration (5%, 10% and 15%). The influence of xylanase addition on the ethanol yield was studied as well.Results show that endo-xylanases improved glucan conversion and ethanol yield compared with a standard enzymatic mixture, markedly at low substrate concentration. The positive effect of added xylanase was most evident at early stages of enzymatic hydrolysis. Regarding process configurations for the period of 72 h, SSF with endo-xylanases provided the best ethanol yield, nearly 70%, for 10% WIS. Nonetheless, the higher ethanol concentration, 29.4 g/l, was obtained at 15% WIS. 相似文献
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Beatriz Palmarola‐Adrados Mats Galbe Guido Zacchi 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(1):85-91
This paper reports on the optimization of steam pretreatment of barley husk for high pentose and hexose recovery in the subsequent enzymatic hydrolysis step, as well as high ethanol yield, following simultaneous saccharification and fermentation. The parameters optimized in the steam pretreatment step were residence time (5–15 min), temperature (190–215 °C), and concentration of the acid catalyst (0 or 0.5% H2SO4). A microwave oven was employed for screening of the optimal conditions to obtain the highest sugar yield following combined pretreatment and enzymatic hydrolysis. The final optimization of the pretreatment prior to enzymatic hydrolysis was performed on a larger scale, in a steam pretreatment unit. Simultaneous saccharification and fermentation was carried out following steam pretreatment on 5 and 10% dry matter steam‐pretreated slurries. Fermentability tests were performed to determine the effect of by‐products (ie furfural and 5‐hydroxymethyl furfural) in the bioconversion of glucose to ethanol by baker's yeast. The maximum glucose yield, 88% of the theoretical, was obtained following steam pretreatment with 0.5% H2SO4 at 200 °C for 10 min. Under these conditions, a sugar to ethanol conversion of 81% was attained in simultaneous saccharification and fermentation. Copyright © 2004 Society of Chemical Industry 相似文献