乙醇催化转化到丁醇研究进展

乙醇的规模化生产和其在汽油中有限的添加量推动了乙醇的高值化利用。由于丁醇具有独特的物化性能,将乙醇一步催化转化为丁醇受到人们的普遍关注。本文主要综述了乙醇催化转化到丁醇的最新研究进展,阐述了不同均相催化剂、羟基磷灰石、氧化物和金属促进氧化物催化剂对乙醇转化率和丁醇选择性的影响,探讨了典型催化剂上乙醇催化转化到丁醇中的双分子机理和Guerbet机理,总结了乙醇催化转化到丁醇中存在的问题、机遇和挑战。提出未来乙醇催化转化的研究重点应该放在高乙醇转化率下丁醇的选择性控制上,即利用均相催化剂研究策略,借助近原位条件下反应机理研究的结果,设计合成新型催化剂体系,实现乙醇到丁醇的高效转化。     

生物燃料的技术现状及研究趋势分析

生物液体燃料(燃料乙醇、生物柴油、生物丁醇等)是生物能源战略的重要组成部分,世界范围内产业化运作的液体生物燃料主要包括生物柴油和燃料乙醇。重点对生物柴油和纤维素乙醇这两种生物燃料的技术现状和技术研究趋势进行分析。工业生产生物柴油的主要方法是酯交换法,即利用动植物油脂和低碳醇在催化剂的作用下经酯交换反应生成脂肪酸酯。纤维素乙醇技术目前主要研究集中在开发可高效水解新型木质纤维素原料;开发新型温和预处理工艺;开发新型高效纤维素降解酶系;开发木质素高效利用产品;开发乙醇发酵基因工程菌株这五个方面。还对生物柴油和纤维素乙醇的研究趋势进行了方向性的分析。     

木质纤维素类生物质制取燃料及化学品的研究进展

木质纤维素类生物质含有丰富的纤维素和半纤维素多糖,通过微生物发酵将它们转化为能源及高附加值的化学品,对于缓解全球能源危机带来的压力和解决环境污染问题具有重要意义。介绍了木质纤维素类生物质的结构特征;评述了预处理方法,包括稀酸、高温液态水蒸气爆破、CO2爆破、氨爆、碱法、有机溶剂法、生物处理法;重点介绍由生物质生产乙醇、丁醇及生物柴油的研究现状。指出开发高效环保的预处理方法、构建耐毒高产菌株和应用连续发酵或补料批式发酵方式等是加快木质纤维素类生物质发酵利用工业化进程的关键所在。     

木质纤维素水解液中酚类抑制物去除的研究进展CSCD

利用木质纤维素水解液发酵产乙醇、丁醇已成为一种极具发展前景的可再生能源生产方式。然而,木质纤维素水解液中产生的酚类物质对发酵起抑制作用并严重阻碍溶剂产生。文章系统介绍了木质纤维素水解液中产生的酚类物质含量及其对终产物发酵的影响,综述了近年来国内外利用生物法去除酚类的效果,阐述了自脱毒发酵菌株的构建。最后,对如何提高水解液中抑制物去除率提出建议与展望。     

新一代的生物燃料——丁醇的开发动向

作为新一代的生物燃料,生物丁醇因其物理性能、燃烧性能优于生物乙醇,越来越受到人们的关注。生物丁醇的开发,对缓解能源危机,保护环境具有重要的意义。对生物丁醇与生物乙醇的性能进行了比较,介绍了生物丁醇的开发动向。     

生物技术在化工领域中的应用

生物技术是微生物学、生物化学、遗传学和生物工程等多学科的综合,包括基因工程、细胞工程、发酵工程、酶工程。其涉及到工业、农业、医药、环保和能源等各个方面,也为化学工业开辟了一条新途径,创造了新资源。人们通过生物技术,把生物资源转化为化工产品,或利用生物技术来合成化工产品。一、制取化工产品 1.制备基础化工原料乙醇、丙酮、丁醇、丁酸及醋酸乙酯等是有机合成、塑料、树脂、橡胶、涂料等化工领域中必不可少的化工原料,以前在很大程度上依靠生物发酵的方法来制取,并已有悠久的历史,如用玉米、薯干等生产乙醇、丙酮、丁醇等。由于这种方法粮耗多、能耗高、菌种性能不佳、废醪污染严重等原因,已面临石油化工的严峻挑战。但是随着石油资源的紧张及生物技术的进步,     

丙酮-丁醇发酵分离耦合技术的研究进展

介绍了近年来采用吸附、气提、液液萃取和渗透汽化从丙酮-丁醇发酵体系中分离丙酮,丁醇、乙醇的研究进展及最新的应用动态,评述了上述几种方法在分离丙酮.丁醇发酵产物(丙酮、丁醇、乙醇等)方面的优点和不足,并对各类方法做了比较,最后对丙酮.丁醇发酵分离耦合的发展方向进行了展望.     

纤维素水解液中木糖发酵制丁醇

对实验室菌种进行筛选后,得到一株能利用纤维素水解液木糖发酵生产丁醇的菌株。研究发现,该菌株不仅能利用水解液中的葡萄糖,还可以利用水解液中的木糖。对菌种生长特性探索,批式发酵中碳源、氮源以及CaCO3等条件优化后,得到最佳种子培养时间为20～24 h,并确定了木糖浓度为20 g/L的纤维素水解液用于15 L发酵罐实验,在37 ℃静置培养84 h,丁醇产量10.95 g/L,总溶剂16.78 g/L（丙酮、乙醇、丁醇三者之和）,木糖利用率达到70%以上,总溶剂转化率为39.4%。解决了纤维素水解液中木糖不能被利用而造成的经济损失问题。     

未来的能源之星——生物丁醇

第二代生物燃料目前包括纤维素乙醇、生物丁醇和混合醇。生物丁醇克服了乙醇的诸多缺点,与乙醇比有不可比拟的优势,主要体现在以下几方面：生物丁醇可在供应链的任何一个环节进行混合,而不致造成系统或原料方面的问题;若发生泄漏,则其在地下水中的扩散有限;能以较高比例与汽油混合,也可单独使用在所有汽油发动机中,与乙醇汽油比,可达到更长的车辆汽油里程;可由石油管道输送,而乙醇不可以;有利于保护生态环境;其正丁醚衍生物可用作柴油。除了其固有的优势外,     

汽爆秸秆膜循环酶解耦合丙酮丁醇发酵

利用新型的汽爆玉米秸秆膜循环酶解耦合发酵系统进行了丙酮丁醇发酵的研究,并对使用该系统所导致的丙酮丁醇梭菌(Clostridium acetobutylicum AS1.132)代谢的变化进行了讨论. 在稀释率为0.075 h-1的条件下,丁醇的产量为0.14 g/g (纤维素+半纤维素),最大丁醇产率达到0.31 g/(L×h),溶剂组成为丁醇:丙酮:乙醇65.3:24.3:10.4(体积比),纤维素和半纤维素的转化率分别为72%和80%,使用单位纤维素酶所产生的丁醇量为3.9 mg/IU,是分步水解批次发酵的1.5倍. 利用该系统使酶解和发酵分别在各自最适的条件下同时连续进行,减少了纤维素酶的用量,有效地解除了酶解产物对纤维素酶的抑制作用,并减轻了溶剂产物尤其是丁醇对微生物活性的影响,延长了发酵周期.     

Butanol production in a sugarcane biorefinery using ethanol as feedstock. Part II: Integration to a second generation sugarcane distillery

Production of second generation ethanol and other added value chemicals from sugarcane bagasse and straw integrated to first generation sugarcane biorefineries presents large potential for industrial implementation, since part of the infrastructure where first generation ethanol is produced may be shared between both plants. In this context, butanol from renewable resources has attracted increasing interest, mostly for its use as a drop in liquid biofuel for transportation, since its energy density is greater than that of ethanol, but also for its use as feedstock in the chemical industry. In this paper, vapor-phase catalytic production of butanol from first and second generation ethanol in a sugarcane biorefinery was assessed, using data available from the literature. The objective is to evaluate the potential of butanol either as fuel or feedstock for industry, taking into account economical/environmental issues through computer simulation. The results obtained show that, although promising, butanol sold as chemical has a limited market and as fuel presents economic constraints. In addition, investments on the butanol conversion plant could be an obstacle to its practical implementation. Nevertheless, environmental assessment pointed out advantages of its use as fuel for road transportation, if compared with gasoline in terms of global environmental impacts such as global warming.     

Butanol production in a sugarcane biorefinery using ethanol as feedstock. Part I: Integration to a first generation sugarcane distillery

Butanol production from renewable resources has been increasingly investigated over the past decade, mostly for its use as a liquid biofuel for road transportation, since its energy density is higher than that of ethanol and it may be used in gasoline driven engines with practically no changes, but also for use as a feedstock in the chemical industry. Most of the research concerning butanol production focuses on the ABE process (fermentation of sugars into a mixture of acetone, butanol and ethanol), which has several drawbacks regarding microorganism performance and product inhibition. An alternative to ABE fermentation, ethanol catalytic conversion to butanol can produce a higher quality product with less retrofitting than ABE in existing ethanol producing facilities. There are different types of catalysts for the chemical conversion of ethanol to butanol being developed in laboratory scale, but their actual use in a sugarcane processing plant has never before been assessed. Butanol production from ethanol in a sugarcane biorefinery, using data from the literature, was assessed in this study; different technological alternatives (catalytic routes) were evaluated through computer simulation in Aspen Plus (including production of electricity, sugar, ethanol and other products) and economic and environmental impacts were assessed. Results indicate that vapor-phase catalysis presents higher potential for industrial implementation, and commercialization of butanol for use as a chemical feedstock has an economic performance similar to that of current, optimized first generation sugarcane distilleries, but can potentially contribute to cost reduction that will allow commercialization of butanol as a fuel in the future.     

Liquid–Liquid Extraction of Butanol from Dilute Aqueous Solutions Using Soybean-Derived Biodiesel

Liquid–liquid extraction (LLE) of mixtures of butanol, 1,3-propanediol (PDO), and ethanol was performed using soybean-derived biodiesel as the extractant. The composition of the mixtures simulated the product of the anaerobic fermentation of biodiesel-derived crude glycerol, which has recently been reported for the first time by the authors. Using a biodiesel: with an aqueous phase volume ratio of 1:1, butanol recovery ranged from 45 to 51% at initial butanol concentrations of 150 and 225 mM, respectively. Less than 10% of the ethanol was extracted, and essentially no PDO was extracted. The partition coefficient for butanol in biodiesel was determined to be 0.91 ± 0.097. This partition coefficient is less than that of oleyl alcohol, which is considered the standard for LLE. However, butanol is suitable for blending with biodiesel, which would eliminate the need for separating the butanol after extraction. Additionally, biodiesel is much less costly than oleyl alcohol. If biodiesel-derived glycerol is used as the feedstock for butanol production, and biodiesel is used as the extractant to recover butanol from the fermentation broth, production of a biodiesel/butanol fuel blend could be a fully integrated process within a biodiesel facility. This process could ultimately help reduce the cost of butanol separation and ultimately help improve the overall economics of butanol fermentation using renewable feedstocks.     

Extraction of Phospholipids from Egg Yolk Flakes Using Aqueous Alcohols

Two alcohols, ethanol and butanol, with different water contents were evaluated for phospholipids (PL) sequential extraction from drum dried egg yolk flakes. It showed that butanol was more effective in extracting total yolk lipids compared to ethanol, but the PL in the extract had the same concentration as in the original yolk total lipid. The use of aqueous ethanol of 95 and 75% resulted in lipid extracts with higher PL concentration during the initial stages of the sequential extraction. When ethanol was further diluted to a concentration of 55%, the solvent lost its PL extraction ability, and the total lipid recovery also decreased dramatically. When both the PL purity and recovery were considered, 75% ethanol was the most effective aqueous alcohol for PL extraction and enrichment from the yolk flakes. In the first stage of extraction using such a solvent, 67% of the total PL in the original yolk was recovered in a lipid fraction with a PL purity of 75%. This study identified the optimal ethanol concentration for PL extraction from dried egg yolk. With this information, the best solid:solvent ratio can be designed to extract and enrich the polar lipids from lipid-bearing materials with known moisture content using a renewable or “green” solvent, ethanol.     

Cell‐free ethanol production: the future of fuel ethanol?

The production of fuel ethanol from renewable resources as an economically viable alternative to gasoline is currently the subject of much research. Most studies seek to improve process efficiency by increasing the rate of ethanol production; ultimately, this approach will be limited by the selected ethanol‐producing microorganism. Cell‐free ethanol production, using only the enzymes involved in the conversion of glucose to ethanol, may offer a practical and beneficial alternative. Mathematical modeling of such a system has suggested that a cell‐free process should be capable of producing ethanol much more efficiently than the microbial based process. This finding along with other potential benefits of a microorganism‐free process suggests that a cell‐free process might significantly improve the economy of fuel ethanol production and is a worthy target for further research. Copyright © 2007 Society of Chemical Industry     

First-principles modeling for optimal design,operation, and integration of energy conversion and storage systems

Energy and electricity consumption is expected to increase in the foreseeable future. Concurrently, sustainability concerns of fossil-based energy resources have motivated the use of renewable and reusable energy resources, and the use of more efficient energy-converting and energy-consuming systems. Consequently, for the past decade, there have been major theoretical and experimental advances in (1) energy generation from renewable and reusable resources and (2) energy-consuming and energy-converting devices. This review article focuses on the recent theoretical advances in renewable energy conversion devices such as photovoltaic and fuel cells, and in energy storage devices such as rechargeable batteries, flow batteries, and supercapacitors. Due to similar chemistry, electrochemistry, and physics of these systems, modeling similarities between different energy systems are highlighted. This review puts into perspective how first-principles mathematical modeling has contributed to systematic advances in the optimal design, operation, and integration of these systems. © 2018 American Institute of Chemical Engineers AIChE J, 65: e16482 2019     

生物质在能源资源替代中的途径及前景展望

化石能源,特别是石油资源的日益短缺,促使人们不断开发新的可再生能源来替代目前的化石能源。本文介绍了生物质在能源和化工领域替代石油资源的各种可能途径,分析了这些途径的发展前景,提出了各种生物质资源不但能够成为石油资源的直接替代,如燃料乙醇、生物柴油等;而且能够成为开发各种化工产品的资源平台,形成对石油化工产品的产业竞争,实现对石油资源的间接替代,如各种生物基基本有机化学品和功能性高分子材料等。开发生物质转化制液体燃料技术和生物化工技术将对石化工业的发展起到推动作用,有助于石油化工产业的可持续发展。     

新时期C4馏分中异丁烯综合利用分析

随着国家对生物燃料乙醇生产和推广使用车用乙醇汽油的方案实施,C_4馏分中异丁烯的利用引起科研工作者和石油炼制行业的思考。我国C_4资源利用尤其是异丁烯一直以来主要依靠甲基叔丁基醚(MTBE)生产路线,其中,90%用于汽油辛烷值添加剂。汽车能源清洁化是新能源发展必由之路,我国的能源结构正在经历前所未有的全面重构,如何应对逐渐步入的乙醇汽油时代?如何满足汽油的清洁绿色性能?异丁烯等C_4资源如何重新布局?这些成为各石油化工企业的很难面对又不得不面对的困惑。着重介绍可改造或代替MTBE生产过程,为C_4资源尤其是异丁烯的综合利用提供出路的主要技术,并对不同技术进行工艺特点、产品性质与市场应用等方面的分析,为市场应对新时期清洁燃料等需求提供借鉴与帮助。     

Ethanol—the primary renewable liquid fuel

This perspective paper establishes that ethanol has a long history of very good performance as a renewable liquid fuel blended with gasoline and can be used in over 80% of the automobile and other light duty transportation vehicles. It fits very well into the future of the combination of electricity and renewable liquid fuel for such transportation. It has also been established that renewable biomass feedstock is highly oxygenated and ethanol can be produced with high yields and efficiency with some conversion technologies—particularly the ‘Hybrid’ of gasification with bioconversion—that have been developed to the commercial implementation stage. Recent major studies conducted by the USDA, DOE and major National Laboratories have projected that large and sustainable biomass feedstock supplies are available and are going to be available to efficiently produce this ethanol in very large quantities of around 340 billion liters per year in the USA. The experience gained over the past 70 years in the south‐eastern USA has been summarized to further support the fact that efficient and sustainable biomass supply can be developed and maintained to support much increased usage. Copyright © 2011 Society of Chemical Industry