A review of the current state of biofuels production from lignocellulosic biomass using thermochemical conversion routes

The rapid increase in energy demand, the extensive use of fossil fuels and the urgent need to reduce the carbon dioxide emissions have raised concerns in the transportation sector. Alternate renewable and sustainable sources have become the ultimate solution to overcome the expected depletion of fossil fuels.The conversion of lignocellulosic biomass to liquid(BtL) transportation fuels seems to be a promising path and presents advantages over first generation biofuels and fossil fuels. Therefore, development of BtL systems is critical to increase the potential of this resource in a sustainable and economic way.Conversion of lignocellulosic BtL transportation fuels, such as, gasoline, diesel and jet fuel can be accomplished through various thermochemical processes and processing routes. The major steps for the production of BtL fuels involve feedstock selection, physical pretreatment, production of bio-oil, upgrading of bio-oil to transportation fuels and recovery of value-added products. The present work is aiming to give a comprehensive review of the current process technologies following these major steps and the current scenarios of biomass to liquid facilities for the production of biofuels.     

Hydrogen from biomass-production by steam reforming of biomass pyrolysis oil

Thermo-conversion of biomass is one of the leading near-term options for renewable production of hydrogen and has the potential to provide a significant fraction of transportation fuel required in the future. We propose a two-step process that starts with fast pyrolysis of biomass, which generates high yields of a liquid product, bio-oil, followed by catalytic steam reforming of bio-oil to produce hydrogen. A major advantage of such a concept results from the fact that bio-oil is much easier and less expensive to transport than either biomass or hydrogen. Therefore, the processing of biomass and the production of hydrogen can be performed at separate locations, optimized with respect to feedstock supply and to hydrogen distribution infrastructure. This approach makes the process very well suited for both centralized and distributed hydrogen production. This work demonstrates reforming of bio-oil in a bench-scale fluidized bed system and provides hydrogen yields obtained using several commercial and custom-made catalysts.     

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.     

甲醇燃料的研究进展与展望

随着化石资源的不断枯竭,能源消费将逐步向可再生能源时期发展.甲醇燃料不仅可以替代汽柴油作为内燃机燃料,而且也可以作为燃料电池等燃料或新型C1化工原料;不仅可以由化石能源生产,而且也可以由可再生能源生产:不仅具有高效、清洁燃料的特征,而且具有生产技术成熟、原料来源丰富的特点,能够实现可持续发展.甲醇燃料是理想的能源载体,在化石能源和可再生能源时期均可发展应用,特别是对于以煤为主要能源的中国,在由化石能源向可再生能源时期过渡的阶段,选择甲醇燃料为发展方向,意义将十分重大.     

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.     

Effect of ethanol–palm kernel oil ratio on alkali-catalyzed biodiesel yield

The finite nature of fossil fuel necessitates consideration of alternative fuel from renewable sources. Palm kernel oil (PKO) has been identified as a renewable resource from which biodiesel can be produced. The effect of ethanol–PKO ratio on PKO biodiesel yield was studied with a view to obtaining optimal feedstock ratio. Experiments were conducted for ethanol–PKO ratios 0.1, 0.125, 0.15, 0.175, 0.2, 0.225 and 0.25 under transesterification conditions of 60 °C temperature, 120 min reaction time and 1.0% KOH catalyst concentration. Results obtained gave 29.5%, 54%, 75%, 89%, 96%, 93.5% and 87.2% average PKO biodiesel yield for the respective feedstock ratios. This shows increase in biodiesel yield with ethanol–PKO ratio up to 0.2. Standard fuel test results of the PKO biodiesel are within biodiesel specifications.     

生物质吸附剂在制备燃料乙醇中应用的研究进展

在最近的几十年中,由于能源短缺和环境恶化,生物质燃料乙醇（BFE）因为其所具有的可循环无污染的优点,引起了人们越来越多的关注。但是在生物燃料乙醇的制备过程中,存在着乙醇脱水工艺能量消耗过大的问题。因此优化乙醇脱水过程一直是人们研究的重中之重。本文简述了国内外吸附法分离乙醇和水工艺中使用的吸附剂,指出了生物质吸附剂在燃料乙醇中优于其它吸附剂的特点,重点分析了生物质吸附剂的研究成果及对其的改性研究。分析表明改性后吸附剂不但拥有良好的吸附效果,还可以在吸附操作结束后重新作为发酵制乙醇的原料,以实现资源的充分利用。最后展望了生物质吸附剂在制备燃料乙醇工艺中的发展趋势,即获得更优秀的脱水效果与更完善的循环利用过程。     

清洁能源——生物质秸秆的研究进展

介绍了研究清洁能源——生物质秸秆的必要性,综述了生物质秸秆的研究进展,对秸秆发电、制燃料乙醇、生产沼气、热解气法制可燃气等作了详细的论述,提出了秸杆作为21世纪最具开发价值的绿色可再生能源,应加大其研究力度。     

Recent Developments in the Conversion of Biomass to Renewable Fuels and Chemicals

The rapid and ongoing increase in consumption of petroleum for transportation fuels, chemicals and energy is not sustainable. Therefore, development of technology that uses agricultural, animal, forestry and municipal solid waste as renewable feedstock is critical to the US economy and national security, and presents a significant opportunity for new catalysis, chemistry and process research. This paper will outline recent developments on the conversion of biomass to renewable fuels and chemicals with emphasis on new opportunities for thermochemical catalysis.     

乙醇补料发酵技术研究进展

作为一种可再生的清洁能源,燃料乙醇的开发利用备受关注,对其发酵工艺的研究也日益深入。近年来,补料发酵工艺逐渐应用于燃料乙醇的生产研究中,并以其降低基质抑制和减轻纤维素稀酸水解液中有毒成分的影响等优点而显示了良好的发展潜力,但由于发酵过程的复杂性和对补料控制策略的研究尚不深入等存在的问题,使该技术在燃料乙醇规模化生产中的应用受到制约。本文介绍了国内外乙醇补料发酵研究的主要进展,着重概述补料发酵技术在乙醇两大重要发酵工艺——纤维素乙醇工艺和超高浓度乙醇发酵工艺中的应用以及补料调控策略等,并提出该领域进一步研究应留意的方向,如应加强乙醇补料发酵动力学和控制理论、新型传感器与在线监测技术等方面的研究。     

Oxygenated transportation fuels. Evaluation of properties and emission performance in light-duty vehicles in Mexico

Recently a “Biofuels Promotion and Development Law” was approved in Mexico that requires increasing volumes of renewable to blend into the transportation fuel pool, much of which is likely to be ethanol. Emissions data under the three different driving conditions of the United States FTP-75 certification cycle were obtained for regulated, toxic and carbonyl compounds using recent model year vehicles representing 61% of the typical fleet available in Mexico. Ozone-forming potential and specific reactivity of tailpipe and evaporative emissions were also calculated. Comparison were performed using the traditional methyl-tertiary butyl ether employed in Mexico with an ethanol fuel at the same level of oxygen content, taking into account the current fuel specifications and the stream stocks available at the Mexican refineries. The results suggest that the contribution of cold start to regulated emissions range from 37% to 40% whiles those of toxic from 40% to 47% in both fuels. Results also indicate an increase in the rates of evaporative emissions of higher Specific Reactivy with the ethanol fuel. Estimation of the percent reduction of pollutants using the Complex Model of the USA Environmental Protection Agency suggests that volatile organic compounds will exceeds the limits imposed by the model if vapour pressure of the ethanol gasoline is not properly adjusted.     

生物质能源转化技术与应用(Ⅳ)——生物质热解气化技术研究和应用

生物质能源是惟一可再生、可替代化石能源转换成气态、液态和固态燃料以及其他化工原料或者产品的碳资源。随着化石能源的枯竭和人类对全球性环境问题的关注,生物质能源替代化石能源利用的研究和开发,已成为国内外众多学者研究和关注的热点。本系列讲座主要讲述以生物质资源为主要原料,通过不同途径转化为洁净的、高品位的气体、液体或固体燃料。本讲主要对生物质的热解气化方式进行了介绍,着重介绍了生物质气化集中供气、供热、发电、合成液体燃料、制氢等技术方面的研究和应用现状,并指出了目前存在的主要问题,提出了我国在生物质气化领域的重点研究方向。     

我国燃料乙醇生产技术现状与发展前景分析

资源和能源是人类社会生存和发展的永恒需求,当前用以支撑全球经济发展的石油资源及能源供应正面临严峻挑战。燃料乙醇作为新的可再生的燃料替代品,可直接用作液体燃料或者同汽油混合使用,减少对不可再生能源——石油的依赖,保障本国的能源安全而日益受到各国的重视。作者介绍了国内外燃料乙醇生产技术概况与研究发展现状,分析了我国发展非粮燃料乙醇的必要性及存在的技术关键和发展前景。指出从长远来看,生产纤维质原料燃料乙醇是燃料乙醇发展的根本出路。     

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。     

生物质能源转化技术与应用(Ⅱ) ——生物质压缩成型燃料生产技术和设备

生物质能源是唯一可再生、可替代化石能源转化成气态、液态和固态燃料以及其它化工原料或者产品的碳资源。随着化石能源的枯竭和人类对全球性环境问题的关注,生物质能源替代化石能源利用的研究和开发,已成为国内外众多学者研究和关注的热点。本系列讲座主要讲述以生物质资源为主要原料,通过不同途径转化为洁净的、高品位的气体、液体或固体燃料。本讲主要综述生物质成型燃料的种类、研究与开发利用进展状况。重点讨论了生物质成型燃料的生产技术和设备,并指出了目前存在的主要问题和今后的发展方向。     

论生物质能源标准体系(Ⅱ)——生物质燃料乙醇标准化研究进展

生物质能源是清洁可再生能源,本系列讲座以生物质能源主要产品为对象,以产品的物理形态为分类依据,在分析研究国际主要产品标准化的基础上进行我国生物质能源标准体系的构建。本讲在对国内外生物质燃料乙醇产业发展状况进行深入剖析的基础上,重点介绍了世界上典型国家燃料乙醇产品标准,并对产品的性能指标进行了对比。针对我国燃料乙醇的产业及标准化现状,提出我国燃料乙醇标准化应加强非食用生物质基和木质纤维基乙醇的相关标准的研究。可通过采标的方式,大力推进我国燃料乙醇相关标准的制订。     

后石油时代与生物质液体燃料

进入后石油时代后,生物质液体燃料燃料乙醇和生物柴油受到关注。利用秸秆代替粮食生产燃料乙醇是解决乙醇原料的根本出路,美国正在研究以小麦和大麦秸秆生产燃料乙醇的可行性,我国河南天冠集团已拥有了多项用秸秆生产乙醇的关键技术。标准系列化是我国生物柴油产业做大的关键。     

The role of butanol in the development of sustainable fuel technologies

OVERVIEW: The development of innovative methods to efficiently convert biomass to fuels and industrial chemicals is one of the grand challenges of the current age. n‐Butanol is a versatile and sustainable platform chemical that can be produced from a variety of waste biomass sources. The emergence of new technologies for the production of fuels and chemicals from butanol will allow it to be a significant component of a necessarily dynamic and multifaceted solution to the current global energy crisis. IMPACT: The production of butanol from biomass and its utilization as a precursor to a diverse set of fuel products has the potential to reduce petroleum use worldwide. In concert with other emerging renewable technologies, significant reductions in greenhouse gas emissions may be realized. The rapid incorporation of renewables into the world fuel supply may also help to offset predicted increases in transportation fuel prices as the supply of oil declines. APPLICATIONS: Recent work has shown that butanol is a potential gasoline replacement that can also be blended in significant quantities with conventional diesel fuel. These efforts have transitioned to research focused on the development of viable methods for the production of an array of oxygenated and fully saturated jet and diesel fuels from butanol. The technologies discussed in this paper will help drive the commercialization and utilization of a spectrum of butanol based sustainable fuels that can supplement and partially displace conventional petroleum derived fuels. Published 2010 by John Wiley and Sons, Ltd.     

生物质能源转化技术与应用(Ⅰ)

生物质能源是唯一可再生、可替代化石能源转化成液态和气态燃料以及其它化工原料或者产品的碳资源。随着化石能源的枯竭和人类对全球性环境问题的关注,生物质能替代化石能源利用的研究和开发,已成为国内外众多学者研究和关注的热点。本文综述了我国年可获得生物质资源量达到3.14亿吨煤当量,其中秸秆和薪材分别占 54% 和 36%;现有180多亿吨林木生物质资源量、8~10亿吨可获得量和3亿吨可作为能源的利用量。生物质能转化利用的主要途径是:热化学高效转化利用的热解气化发电(供热、供气)、快速热解制备液体燃料和生物质气化合成液体燃料,以及生物化学转化技术等。同时,论述了目前已经进行的生物质研究开发技术和产业化利用进展。     

Mixed methanol-ethanol technology to produce greener biodiesel from waste cooking oil: A breakthrough for SO4/SnO2-SiO2 catalyst

World energy crisis has become the foremost crucial topic in this new era. Unstable price of petroleum fuel in the world market and recent environmental concerns on gas emission during combustion have led to intensive search for alternative energy sources that are not only renewable but sustainable. Without doubt, one of the most important evolutions in the renewable energy sector is the development of biodiesel. Currently commercial biodiesel production is using methanol (non-renewable) as the main reactant to produce biodiesel due to its wide availability and low cost. However, biodiesel produced using methanol are not completely renewable as methanol can only be derived from petroleum fuel. Unfortunately, not much attention has been given on this issue. On the other hand, ethanol may emerge as a good solution to this problem as ethanol can be derived from renewable sources through fermentation process. The only constraint on the use of ethanol is its slow reaction rate in transesterification reaction and therefore resulted to energy inefficient biodiesel production process. Such limitations worsen if solid acid catalyst is used in the reaction. Thus, the aim of this present work is to introduce a simple mixed methanol-ethanol method to overcome these limitations and to produce biodiesel in a greener and sustainable manner. The effect of methanol to ethanol to oil molar ratio, reaction temperature, catalyst loading and reaction time towards biodiesel yield are discussed in detail. From this study, it was found that an optimum biodiesel yield of 81.4% can be attained at a relatively short reaction time of 1 h.