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中国面临着严重的能源短缺和环境污染问题,中国政府正在局部几个省份内政策性鼓励燃料乙醇生产和使用.尽管当前主要是用玉米和谷物作为生产乙醇的原料,然而中国具有大量潜在的低成本的纤维素生物质原料,可以极大地扩大乙醇的产量,降低原料成本.近20年来,由于技术的革命性进步,已使得纤维素乙醇的生产成本从4美元/加仑以上,降低至约1.2-1.5美元/加仑.其中,每吨生物质约44美元.因此,目前乙醇掺汽油具有十分强的市场竞争力.已有几个公司正在建造首批商业纤维素乙醇工厂,虽然这些刚起步的小型设施在合理利用和管理上风险较小,但规模经济需要较大型工厂.尽管配送生物质原料的成本会随需求的增加而增加,但在乙醇生产基础上的生物精炼技术的发展,尤其是化工产品和动力的协同生产,将会使全过程的经济可行性大大提高.进一步深入的基础研究,将解决低成本下实现纤维素的完全利用,以确保在无政策性补贴的前提下,真正使纤维素乙醇成为具有市场竞争力的低成本纯液体燃料. 相似文献
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中国面临着严重的能源短缺和环境污染问题,中国政府正在局部几个省份内政策性鼓励燃料乙醇生产和使用。尽管当前主要是用玉米和谷物作为生产乙醇的原料,然而中国具有大量潜在的低成本的纤维素生物质原料,可以极大地扩大乙醇的产量,降低原料成本。近20年来,由于技术的革命性进步,已使得纤维素乙醇的生产成本从4美元/加仑以上,降低至约1.2—1.5美元/加仑。其中,每吨生物质约44美元。因此,目前乙醇掺汽油具有十分强的市场竞争力。已有几个公司正在建造首批商业纤维素乙醇工厂,虽然这些刚起步的小型设施在合理利用和管理上风险较小,但规模经济需要较大型工厂。尽管配送生物质原料的成本会随需求的增加而增加,但在乙醇生产基础上的生物精炼技术的发展,尤其是化工产品和动力的协同生产,将会使全过程的经济可行性大大提高。进一步深入的基础研究,将解决低成本下实现纤维素的完全利用,以确保在无政策性补贴的前提下,真正使纤维素乙醇成为具有市场竞争力的低成本纯液体燃料。 相似文献
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由于能发挥缓解能源紧张、减少环境污染、促进农村发展等重要作用,利用年产量巨大的植物纤维资源,生产可再生性液体替代燃料乙醇的技术受到了巨大的关注,成为工业生物技术的研究热点.酶法生产纤维素乙醇面临多种困难:纤维素原料比重轻,收集运输不便;原料结构复杂,需要深度预处理;纤维素酶系的酶解效率有待提高;半纤维素中的木糖难以发酵转化为乙醇等.经过多年研究,新技术已经取得重大进展,开始接近实用化.紧迫的社会需求正在迫使国内外政府和企业界大量投资,开展纤维素乙醇的中试研究和试生产,力求在短时期内克服上述难点,尽快实现产业化.充分利用植物纤维资源中的多种组分,联合生产乙醇和部分高值产品的生物精练技术,是实现纤维素乙醇产业化的重要突破口和必然途径.玉米芯生物精练生产乙醇和木糖相关产品的技术正在进行产业化.本文综述了纤维素乙醇产业化的研究进展并做了展望. 相似文献
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纤维素乙醇产业化 总被引:5,自引:0,他引:5
由于能发挥缓解能源紧张、减少环境污染、促进农村发展等重要作用,利用年产量巨大的植物纤维资源,生产可再生性液体替代燃料乙醇的技术受到了巨大的关注,成为工业生物技术的研究热点。酶法生产纤维素乙醇面临多种困难:纤维素原料比重轻,收集运输不便;原料结构复杂,需要深度预处理;纤维素酶系的酶解效率有待提高;半纤维素中的木糖难以发酵转化为乙醇等。经过多年研究,新技术已经取得重大进展,开始接近实用化。紧迫的社会需求正在迫使国内外政府和企业界大量投资,开展纤维素乙醇的中试研究和试生产,力求在短时期内克服上述难点,尽快实现产业化。充分利用植物纤维资源中的多种组分,联合生产乙醇和部分高值产品的生物精练技术,是实现纤维素乙醇产业化的重要突破口和必然途径。玉米芯生物精练生产乙醇和木糖相关产品的技术正在进行产业化。本文综述了纤维素乙醇产业化的研究进展并做了展望。 相似文献
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The projected cost of ethanol production, from cellulosic biomass has been reduced by almost a factor of four over the last
20 yr. Thus, it is now competitive for blending with gasoline, and several companies are working to build the first plants.
However, technology development faced challenges at all levels. Because the benefits of bioethanol were not well understood,
it was imperative to clarify and differentiate its attributes. Process engineering was invaluable in focusing on promising
opportunities for improvements, particularly in light of budget reductions, and in tracking progress toward a competitive
goal. Now it is vital for one or more commercial projects to besuccessful, and improving our understanding of process fundamentals
will reduce the time and costs for commercialization. Additionally, the cost of bioethanol, must be cut further to be competitive
as a pure fuel in the open market, and aggressive technology advances are required to meet this target. 相似文献
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The Department of Energy’s Office of the Biomass Program has set goals of making ethanol cost competitive by 2012 and replacing
30% of 2004 transportation supply with biofuels by 2030. Both goals require improvements in conversions of cellulosic biomass
to sugars as well as improvements in fermentation rates and yields. Current best pretreatment processes are reasonably efficient
at making the cellulose/hemicellulose/lignin matrix amenable to enzymatic hydrolysis and fermentation, but they release a
number of toxic compounds into the hydrolysate which inhibit the growth and ethanol productivity of fermentation organisms.
Conditioning methods designed to reduce the toxicity of hydrolysates are effective, but add to process costs and tend to reduce
sugar yields, thus adding significantly to the final cost of production. Reducing the cost of cellulosic ethanol production
will likely require enhanced understanding of the source and mode of action of hydrolysate toxic compounds, the means by which
some organisms resist the actions of these compounds, and the methodology and mechanisms for conditioning hydrolysate to reduce
toxicity. This review will provide an update on the state of knowledge in these areas and can provide insights useful for
the crafting of hypotheses for improvements in pretreatment, conditioning, and fermentation organisms. 相似文献
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Cesar B. Granda Mark T. Holtzapple Gary Luce Katherine Searcy Darryl L. Mamrosh 《Applied biochemistry and biotechnology》2009,156(1-3):107-124
The MixAlco process employs a mixed culture of acid-forming microorganisms to convert biomass to carboxylate salts, which are concentrated via vapor-compression evaporation and subsequently chemically converted to other chemical and fuel products. To make alcohols, hydrogen is required, which can be supplied from a number of processes, including gasifying biomass, separation from fermentor gases, methane reforming, or electrolysis. Using zeolite catalysts, the alcohols can be oligomerized into hydrocarbons, such as gasoline. A 40-tonne/h plant processing municipal solid waste ($45/tonne tipping fee) and using hydrogen from a pipeline or refinery ($2.00/kg H2) can sell alcohols for $1.13/gal or gasoline for $1.75/gal with a 15% return on investment ($0.61/gal of alcohol or $0.99/gal of gasoline for cash costs only). The capital cost is $1.95/annual gallon of mixed alcohols. An 800-tonne/h plant processing high-yield biomass ($60/tonne) and gasifying fermentation residues and waste biomass to hydrogen ($1.42/kg H2) can sell alcohols for $1.33/gal or gasoline for $2.04/gal with a 15% return on investment ($1.08/gal of alcohol or $1.68/gal of gasoline for cash costs only). The capital cost for the alcohol and gasification plants at 800 tonnes/h is $1.45/annual gallon of mixed alcohols. 相似文献
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Recent studies have proven ethanol to be the idael liquid fuel for transportation, and renewable ligno cellulosic materials
to be the attractive feed stocks for ethanol fuel production by fermentation. The major fermentable sugars from hydrolysis
of most cellulosic biomass are D-glucose and D-xylose. The naturally occurring Saccharomyces yeasts that are used by industry to produce ethanol from starches and cane sugar cannot metabolize xylose. Our group at Purdue
University succeded in developing genetically engineered Saccharomyces yeasts capable of effectively cofermenting glucose and xylose to ethanol, which was accomplished by cloning three xylose-metabolizing
genes into the yeast. In this study, we demonstrated that our stable recombinant Sacharomyces yeast, 424A (LNH-ST), which contains the cloned xylose-metabolizing genes stably integrated into the yeast chromosome in
high copy numbers, can efficiently ferment glucose and xylose present in hydrolysates from different cellulosic biomass to
ethanol. 相似文献
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Technoeconomic analysis has been used to guide the research and development of lignocellulosic biofuels production processes
for over two decades. Such analysis has served to identify the key technical barriers for these conversion processes so that
research can be targeted most effectively on the pertinent challenges. The tools and methodology used to develop conceptual
conversion processes and analyze their economics are presented here. In addition, the current process design and economic
results are described for dilute acid pretreatment followed by enzymatic hydrolysis and fermentation. Modeled ethanol costs
of $1.33/gallon (in consistent year 2007 dollars) are being targeted for this commercial scale corn stover conversion process
in 2012. State of technology models, which take actual research results and project them to commercial scale, estimate an
ethanol cost of $2.43/gallon at present. In order to further reduce costs, process improvements must be made in several areas,
including pretreatment, enzymatic hydrolysis, and fermentation. As the biomass industry develops, new fuels and new feedstocks
are being researched. Technoeconomic analysis will play a key role in process development and targeting of technical and economic
barriers for these new fuels and feedstocks.
相似文献
Andy AdenEmail: |
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Applied Biochemistry and Biotechnology - Although lignocellulosic biomass and wastes are targeted as an attractive alternative fermentation feedstock for the production of fuel ethanol, cellulosic... 相似文献
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Ballesteros I. Oliva J. M. Navarro A. A. González A. Carrasco J. Ballesteros M. 《Applied biochemistry and biotechnology》2000,84(1-9):97-110
Although considerable progress has been made in technology for converting lignocellulosic biomass into ethanol, substantial
opportunities still exist toreduce production costs. In biomass pretreatment, reducing milling power is a technological improvement
that will substantially lower production costs for ethanol. Improving sugar yield from hemicellulose hydrolysis would also
reduce ethanol production costs. Thus, it would be desirable to test innovative pretreatment conditions to improve the economics
by reducing electrical power of the milling stage and by optimizing pretreatment recovery of hemicellulose, as well as to
enhance cellulose hydrolysis. The objective of this study was to evaluate the effect of chip size (2–5, 5–8, and 8–12 mm)
on steam-explosion pretreatment (190 and 210°C, 4 and 8 min) of softwood (Pinus pinater). 相似文献
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Hui Wang Darrell Livingston Radhakrishnan Srinivasan Qi Li Philip Steele Fei Yu 《Applied biochemistry and biotechnology》2012,168(6):1568-1583
The sugars present in bio-oil produced by fast pyrolysis can potentially be fermented by microbial organisms to produce cellulosic ethanol. This study shows the potential for microbial digestion of the aqueous fraction of bio-oil in an enrichment medium to consume glucose and produce ethanol. In addition to glucose, inhibitors such as furans and phenols are present in the bio-oil. A pure glucose enrichment medium of 20?g/l was used as a standard to compare with glucose and aqueous fraction mixtures for digestion. Thirty percent by volume of aqueous fraction in media was the maximum additive amount that could be consumed and converted to ethanol. Inhibitors were removed by extraction, activated carbon, air stripping, and microbial methods. After economic analysis, the cost of ethanol using an inexpensive fermentation medium in a large scale plant is approximately $14 per gallon. 相似文献
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Biomass processing plants have a trade-off between two competing cost factors: as size increases, the economy of scale reduces per unit processing cost, while a longer biomass transportation distance increases the delivered cost of biomass. The competition between these cost factors leads to an optimum size at which the cost of energy produced from biomass is minimized. Four processing options are evaluated: power production via direct combustion and via biomass integrated gasification and combined cycle (BIGCC), ethanol production via fermentation, and syndiesel via Fischer Tropsch. The optimum size is calculated as a function of biomass gross yield (the biomass available to the processing plant from the total surrounding area) and processing cost (capital recovery and operating costs). Higher biomass gross yield and higher processing cost each lead to a higher optimum size. For most cases, a small relaxation in the objective of minimum cost, 3%, leads to a halving of plant size. Direct combustion and BIGCC each produce power, with BIGCC having a higher capital cost and conversion efficiency. When the delivered cost of biomass is high, BIGCC produces power at a lower cost than direct combustion. The crossover point at which this occurs is calculated as a function of the purchase cost of biomass and the biomass gross yield. 相似文献