Concentration of Bio-Ethanol through Cellulose Ester Membranes during Temperature-Difference Controlled Evapomeation

To evaluate the high-performance of membrane materials in the concentration of an aqueous solution of dilute bioethanol under temperature-difference controlled evapomeation (TDEV), asymmetric porous cellulose nitrate (CN) and cellulose acetate (CA) membranes were prepared by a phase inversion method. In the concentration of dilute ethanol under TDEV, these membranes showed a high permeation rate and high ethanol/water selectivity. In membranes with almost the similar pore size, the ethanol/water selectivity was considerably higher for the CN membrane than the corresponding CA membrane. This result suggested that the affinity between the membrane material and the permeant is an important factor in the separation selectivity.

Energy-Efficient Production of Cassava-Based Bio-Ethanol

Fuel ethanol is an important renewable and sustainable fuel, produced in China by fermentation of mostly corn, wheat and cassava feedstock. Fermentation produces an ethanol-lean broth (10 to 12 vol%). Ethanol is recovered by distillation, followed by a molecular sieve drying beyond the azeo-tropic point. The distillation and molecular sieve operations consume most of the total energy used, with the steam consumption currently being ~1.8 kg/kg ethanol, including 0.5 kg/kg ethanol in the final molecular sieve stage during regeneration. The objectives of the paper are fourfold: 1) firstly to study the distillation process of a large-scale cassava-based fuel ethanol production (200,000 tons per year), by field measurements and by using an Aspen Plus V8.2 simulation, with and without energy integration of condensers and reboilers, resulting in a distillation steam consumption of ~1.3 kg/kg ethanol;2) secondly, to examine the effects of using Very High Gravity (VHG) fer-mentation of cassava meal mash. By using VHG fermentation, the ethanol concentration in the fermenter broth is significantly increased, to about 19 vol% (15.4 wt%). The steam consumption is then reduced to ~0.94 kg/kg, representing a considerable saving in comparison with the current operation. Applying VHG fermentation needs minor additional investment, rapidly recovered through the energy savings and the smaller size of equipment;3) thirdly, to assess the application of a hybrid operation, where pervaporation will be used to selectively and continuously remove ethanol from the fermenter broth, thus slightly increasing the fermentation yield by reducing the risk of ethanol inhibition, whilst producing an ehtanol-rich permeate (about 30 wt%);and finally 4) to demonstrate that the production cost of cassava-based ethanol can substantially be reduced by applying the proposed improvements.

Evaluation of Plantain Biomass (<i>Musa paradisiaca</i>L.), as Feedstock for Bio-Ethanol Production

This study investigated the viability of post-harvested plantain biomass as a promising feedstock for the production of Bioethanol. The properties of the derived bio-ethanol were determined to examine its suitability as a promising and sustainable alternative to petroleum-based ethanol The research revealed that Plantain biomass is made up of Lignocellulosic contents such as extractive, Lignin, cellulose, hemicelluloses, ash and moisture in different proportions. The different parts of the biomass such as the flower, stem and leaves were hydrolyzed using H2SO4. Optimum hydrolysis conditions of 6%w/v acid concentration, 30 min contact time and 80°C working temperature were established for Plantain stem and flower. However, hydrolysis of Plantain leaves was at the best under the experimental conditions of acid concentration (10% w/v), contact time (120 min) and temperature (120°C). The highest yield of the bio-ethanol produced was obtained from Plantain stem biomass with a record of 8.04% followed by Plantain flower with a yield of 7.73% and 757% from Plantain leaves The hydrolyzate was fermented using Baker’s yeast (Saccharomyces cerevisiae) at a room temperature of 25°C and pH of 4.5 for 4 D. The structural determination of the derived bioethanol was conducted using FT-IR analysis and the fuel properties were found to be consistent with those of the conventional ethanol. The SEM analysis conducted on the post hydrolysed biomass confirmed the effectiveness of the hydrolysis scheme adopted as evident on the surface morphology of the biomass. This study confirmed the viability of Plantain biomass as promising feedstock for Bio-ethanol production under the established hydrolysis conditions.

Life-Cycle Analysis of Bio-Ethanol Fuel Emissions of Transportation Vehicles in Greater Houston Area

Study is conducted on the life cycle assessment of bio-ethanol used for transportation vehicles and their emissions. The emissions that are analyzed include greenhouse gases, volatile organic compounds, sulfur oxide, carbon monoxide, nitrous oxide, particulate matter with the size less than 10 and 2.5 microns. Furthermore, various blends of bio-ethanol and gasoline are studied to learn about the impacts of higher blend on emissions. The Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model software are used to simulate for emissions. The research analyzes two pathways of emissions: Well-to-Pump and Pump-to-Vehicle analyses. It is found that the fuel cell vehicles using 100% bio-ethanol have shown the most reduction in the amount of all the pollutants from the Pump-to-Vehicle emission analysis. The Well-to-Pump analysis shows that only greenhouse gases (GHGs) reduce with higher blends of bio-ethanol. All other pollutants VOC, CO, NOx, SOx, PM10 and PM2.5 emissions increase with the higher blending ratios. The Pump-to-Vehicle analysis shows that all the pollutant emissions reduce with the percentage increase of bio-ethanol in the fuel blends.

A-Site Effect on the Conversion of Bio-Ethanol into Isobutene over Ternary A1ZnyZrzOn Catalysts

Ternary multifunctional A1ZnyZrzOn catalysts are prepared by introducing A-site transition metals with the redox capability into binary Zn1Zr8On. Structure and morphology were investigated by means of XRD, BET and FESEM, respectively. Activity data showed that Cr addition exhibited obvious beneficial effect to promote isobutene production from direct conversion of bio-ethanol compared to other A-site metal dopants. A significant higher yield of isobutene over Cr-promoted Zn1Zr8On catalyst was also observed with respect to its binary Zn1Zr8On counterpart. The choice of A-site metal is of prime importance in the isobutene production, catalyzing mainly the ethanol dehydrogenation, meanwhile the appropriate addition of zinc on the catalyst surface is also essential for good isobutene yield.

Policy Options for China's Bio-ethanol Development and the Implications for Its Agricultural Economy

The present paper analyzes the potential impacts of bio-ethanol expansion on agricultural production, food prices and farmers＇ incomes in different regions of China. The results show that increase in demand for feedstock to produce bio-ethanol will lead to large increase in the prices of agricultural products. The increase in prices will trigger a significant rise in the production of feedstock at the cost of lower rice and wheat production. The study also reveals that the impacts of bio-ethanol on farmers＂ incomes vary largely among regions and farmer groups. Given the expected expansion of bio-ethanol production in the future, and the limited land resources for feedstock production in China, the viability of different crops as feedstock for bio-ethanol requires careful analysis before a large-scale expansion of China＇s bio-ethanol program. Bio-ethanol production in China should be relying more on the second generation of bio-ethanol technologies （i.e. using celluloses to produce bio-ethanol）, and China＇s government should increase research investment in this field.

The Development of Materials for the Production of Hydrogen from Bio-ethanol

1 Results There is an increased interest in the hydrogen production from renewable sources. In this context, recently, numerous studies which use ethanol for hydrogen production have appeared. Ethanol is easily handled, non-toxic, and it can be obtained from biomass. The steam-reforming of bioethanol has been shown to beeffective for hydrogen production:C2H5OH + 3 H2O  6 H2 + 2 CO2. Six moles of hydrogen can be yielded for each mole of ethanol reacted. However, depending on the catalyst used, other und...

强化硫胺素途径能增强工业酵母线粒体稳态

为探索工业酵母在乙醇发酵中的抗逆机制,对多重耐受性工业酵母菌株A233及对照菌株进行转录组学深度分析,结果表明:在37℃条件下,THI80、BUD16等20个硫胺素途径相关基因均发生了显著的差异表达;同时硫胺素依赖性的丙酮酸代谢途径(PDC1、PDC5)和戊糖磷酸途径(TKL1)中的相关基因皆显示了转录上调。针对硫胺素途径基因PHO3、BUD16、SNZ1、PDX3和THI80进一步进行了30和37℃条件下的单基因敲除与过表达实验,并对单基因敲除菌株进行了外源添加硫胺素的回补实验,结果表明:尽管调控硫胺素途径的单个基因对细胞生长和乙醇产量不产生显著的变化,但是编码硫胺素焦磷酸激酶的THI80基因缺失和过表达分别造成30及37℃条件下胞内活性氧(ROS)累积量不同程度的上升、生长活性抑制以及乙醇累积缓慢等现象;同时发现,过表达PHO3、BUD16和PDX3基因使37℃高温胁迫下的线粒体膜电位均显著上升,分别达到了139%、141%和133%,说明强化硫胺素途径对酵母细胞的线粒体稳态有非常积极且显著的影响。

Ca^(2+)络合作用对生物基PA56纤维结构与性能的影响

为探究络合作用对生物基聚酰胺5 6 (PA5 6)纤维结构与性能的影响,以氯化钙为络合剂对PA56纤维进行络合改性,研究氯化钙在不同溶剂(水和乙醇)中对生物基PA56纤维结构与性能的影响。结果表明,经氯化钙溶液处理后,生物基PA56纤维的N—H和C=O的伸缩振动峰位置发生红移,酰胺Ⅱ带发生蓝移;纤维的熔点、结晶度和结晶能力下降,但晶型未发生变化;与水的接触角减小、断裂强度和断裂伸长率下降,纤维表面变得粗糙。相比氯化钙水溶液处理的效果,经氯化钙乙醇溶液处理后纤维的结构和性能变化很大,说明乙醇溶剂更有助于Ca^(2+)与PA纤维聚酰胺基团之间形成络合配位作用。

燃料乙醇来源鉴定方法研究进展

在绿色低碳经济转型的趋势下,准确检测和识别生物燃料、建立燃料乙醇的低碳属性识别体系对于生物质能源的推广至关重要。然而生物基和化石基乙醇因具有完全相同的化学组成而难以区分,生物质来源和加工工艺的日益复杂以及混合燃料中多种添加剂的干扰使得二者的区分更加困难。基于燃料乙醇的产业发展、原料与生产工艺,综述了国内外识别生物基燃料乙醇的方法研究现状及可借鉴的技术,包括放射性^(14)C分析法、特征杂质分析法和稳定同位素比分析法,并对比了各种方法的优缺点和适用范围。在此基础上分析和展望了未来鉴定燃料乙醇来源的相关发展趋势,提出建立乙醇来源相关的杂质分子库、开发针对特征杂质的特异性及快速检测方法等新策略。

生物乙醇制丁二烯催化剂及工艺技术研究进展

生物乙醇作为一种被广泛认可的可代替化石能源生产化工产品的中间能源载体,研究将生物乙醇转化为化工基础原料丁二烯意义重大,该技术工业化的关键是高性能多功能催化剂的开发,当前乙醇制丁二烯催化剂正处于规模化应用的前期阶段。分别介绍生物乙醇制备丁二烯的反应原理,重点综述生物乙醇制丁二烯Mg/Si基催化剂、锆基催化剂、新型催化剂3类相关催化剂的最新研究进展,并分析生物乙醇制备丁二烯工艺技术的最新研究报道。最后分析当前生物乙醇制丁二烯技术的现状,并为提高市场竞争力提出产业化应重点关注的领域。建议加大对生物乙醇一步法制丁二烯多功能催化剂及配套工艺技术的开发力度,形成生物丁二烯成套工艺技术,助力化工产业的碳中和。

炼化油泥醇解制备轻质生物油的研究

通过超临界醇解炼化油泥回收轻质生物油,实验表明340℃、60 min、油泥与乙醇质量比1∶2时油相收率最高(59.37%),且饱和烃与芳香烃含量分别达到15.78%和16.58%。脂肪烃、环烷烃与萘、菲、芴是饱和烃与芳香烃的主要组分,但直链烃在卤素催化下,通过羟基化、羧基化和酯化反应生成脂肪酸脂。油泥中的硫以噻喃形态进入轻质油,但噻喃会在乙醇作用下开环磺化、磺酰缩合使硫转移至沥青质;氮则以吡啶形态进入轻质油,重质油中的氮则以氨基和酰胺形态存在。

中国能源作物生产生物乙醇的潜力及分布特点

基于中国后备土地资源潜力,该文分析了在不影响现有粮食和经济作物种植结构的前提下,利用宜耕边际性土地资源发展生物乙醇能源的生产潜力及空间分布。结果显示:长期而言,中国能源作物生物乙醇的总生产潜力在7400×104 t以上;中短期而言,如果仅考虑其中集中连片的土地资源,则可生产生物乙醇2170×104t,约占中国2006年汽油消费量的41.4%;中国生物乙醇产量潜力区域差异悬殊,潜力最大的几个省(区)依次为新疆、甘肃、山东、江西和宁夏。

中国能源作物甜高粱的空间适宜分布及乙醇生产潜力

甜高粱作为能源作物在世界范围内广受关注,但目前对于甜高粱的空间分布及乙醇生产潜力尚缺乏专门的定量研究。依据气候、土壤、地形和土地利用等空间数据以及相关文献资料,探讨了甜高粱在中国的空间适宜分布。研究表明,我国大部分区域均可种植甜高粱;其中可种植的未利用地面积达5919.2×104hm2,主要集中于新疆和内蒙古等省区;而最适宜甜高粱种植的未利用地面积为286.7×104hm2,主要分布在黑龙江、内蒙古、山东和吉林等地。中国未利用地甜高粱乙醇生产潜力较大,在不考虑其它社会经济限制因素下,总乙醇生产潜力可达11838.5×104t以上。最适宜未利用地的甜高粱乙醇生产潜力为573.4×104-2637.8×104t,平均为1075.2×104t,可满足中国目前E20乙醇汽油84.8%的需求。如在适宜性较差和较适宜的未利用地种植甜高粱,应充分考虑开发成本和能源投入等问题。

木质纤维素类生物质高温液态水预处理技术

木质纤维素燃料乙醇是可再生能源的重要组成部分,其中可发酵糖的制取技术是木质纤维素乙醇化的关键技术之一。原料经过预处理后再进行酶解被认为是最有前景的糖化方式。高温液态水预处理技术与其它方法相比显示了独特的优势,如不需添加化学试剂、降解产物少等。本文在总结了高温液态水性质的基础上,对它在生物质预处理过程中各组分(半纤维素和木质素)的水解过程及机理进行了较详细的综述和分析。最后对高温液态水预处理技术在木质纤维素糖化领域中的研究和应用前景进行了展望。

中国生物质能源与生物质利用现状与展望

分析了生物质能源与生物质利用在解决我国面临的能源危机、三农问题、环境问题上的作用,以及其在可持续发展和循环经济中的地位。总结国内外生物质能源和利用的现状,阐述了我国未来生物能源和生物质利用的发展方向和目标,展望和预测了生物质能源与生物质利用的途径,并对生物质产业发展的组织形式提出建议。

纤维素酶的研究进展与发展趋势

纤维素酶是一类能够水解纤维素的β-D-糖苷键生成葡萄糖的多组分酶的总称。传统上将其分为3类:内切葡聚糖酶、外切葡聚糖酶和β-葡萄糖苷酶。纤维素酶属于糖苷水解酶类,近年来,根据氨基酸序列的同源性以及纤维素酶结构的相似性,将其分成不同的家族。总结了纤维素酶近年来的主要进展与研究趋势,包括酶的作用机理、基因的表达与调控、酶的发酵生产以及在纺织、洗涤、能源等工业的应用进展。

乙醇-生物柴油-柴油混合燃料对柴油机性能和排放的影响

基于乙醇、生物柴油和石化柴油物化性质的互补性,配制了乙醇-生物柴油-柴油混合的多组分燃料(简称BED燃料),在0℃、10℃、15℃、20℃环境下研究了BED燃料相溶性和稳定性,试验研究了6组不同比例BED燃料对柴油机性能和排放的影响。结果表明:在不对柴油机做任何改动的情况下,燃用BED燃料后在中间转速大负荷工况下动力下降较大,下降幅度随乙醇和生物柴油组分的增加而升高,最大降幅达到10.2%;当量燃油消耗率低于纯柴油,在低负荷时,不同比例BED燃料的当量燃油消耗率不呈现明显的变化规律,在高负荷时,当量燃油消耗率随BED燃料含氧量增加而降低,最大下降9.2%;CO排放量在高负荷时明显下降,最大下降70.1%;NOx排放量随BED燃料中生物柴油比例的增加而上升,随乙醇比例的增加而降低,标定工况下最大上升29%;THC排放量随生物柴油比例的增加而下降,随乙醇比例的增加而上升,其中标定工况下最大下降32.6%。

木质纤维素可再生生物质资源预处理技术的研究进展

阐述了由木质纤维素可再生生物质资源制备生物燃料乙醇对我国可持续发展的重要意义。针对木质纤维素可再生生物质资源利用的关键技术,综述了国内外对木质纤维素可再生生物质资源预处理的研究进展,并重点介绍了物理法、化学法、物理-化学法和生物法预处理木质纤维素可再生生物质资源的技术。最后对木质纤维素可再生生物质资源预处理技术和应用前景进行了展望。

纤维素酶研究进展

随着石油资源的日益枯竭,寻求廉价的、清洁的可再生能源成为各国能源领域的重要研究任务。纤维素物质的利用与转化对于解决世界环境污染以及能源危机等问题具有十分重要的意义。纤维素酶能有效地将纤维素物质水解成单糖,进而发酵生产乙醇、氢气以及微生物油脂等,因此纤维素酶日益受到人们的关注。文章在了解了纤维素酶的结构以及作用机理的基础上,对纤维素酶的各种来源、制取工艺和应用领域的研究进展作了详细的介绍,并对其今后的研究趋势进行了展望。