生物柴油发展现状、影响与展望

随着第一代生物液体燃料发展规模的迅速扩大,其发展对农产品价格、粮食安全与环境等方面的影响开始显现,并引起了各国政府和学术界的广泛关注。该文在分析世界主要国家生物柴油发展现状、目标与激励政策的基础上,通过对生物柴油生产的原料需要和技术现状分析,探讨了生物柴油发展对农产品价格与环境等方面的可能影响。研究表明：未来生物柴油持续扩张的趋势不可逆转,将对农产品价格产生较大的上涨压力;生物柴油发展对环境和温室气体排放会产生影响,但影响程度与生产方式及其导致的土地利用变化情况密切有关;中国应重点发展林业生物柴油等“非粮”生物液体燃料产业,并建立有利于该产业健康发展的政策规范。     

生物质资源能源化与高值利用研究现状及发展前景

生物质是唯一能够直接转化为燃料的可再生能源，其开发利用既可以弥补低碳能源的需求，减少环境污染，也是中国实现"碳中和"目标的重要手段。该研究围绕以秸秆为主的生物质资源制备清洁能源和高值利用的总目标，系统分析生物质资源通过生物或热化学等转化途径制备气、液、固三相清洁能源的综合利用技术和模式，重点论述厌氧消化制备生物燃气、水热催化炼制醇烃燃料、裂解液化与生物油提质和生物质制备固体燃料4项技术发展现状与研究进展。在4项生物质转化技术中，厌氧消化制备生物天然气工业化程度最高，由于其大都基于大型养殖场建立，可有效解决原料收集问题，而且厌氧消化技术与沼气净化技术相对较为成熟，生物天然气可直接作为燃料、电力和热力来源供用户使用；由于生物质制备液体燃料中存在转化过程成本较高、产物分离困难、提质效率低、产品不稳定等问题，很难与当前应用端平稳接轨，因此水热催化炼制醇烃燃料、裂解液化制备生物油技术规模化发展水平较低；对于生物质制备固体燃料，其成型技术较为成熟，配套炉具的研发也有效解决了成型燃料应用端的问题，其规模化应用最大的难点在于原料的收集与存储。文章最后对未来生物天然气、生物质液体燃料与固体成型燃料发展前景进行展望，为实现农村生物质资源高效制备清洁能源及高值利用提供借鉴。     

中国生物质能产业发展现状及趋势分析

该文在综合评价中国生物质能资源、产业发展和政策环境的基础上，分析未来生物质能产业发展趋势。中国具有丰富的生物质资源，生物质能产业初具规模：沼气产业基本形成，燃料乙醇年生产能力已达到102万t，开发了甜高粱茎秆等非粮作物生产燃料乙醇的技术，秸秆直燃发电示范工程正式并网运行；促进生物质能产业发展的宏观政策环境逐渐形成。因此得出结论：未来中国生物质能产业发展的重点是沼气及沼气发电、液体燃料、生物质固体成型燃料以及生物质发电；促进生物质能产业发展的政策环境将进一步完善；技术水平进一步提高；将有更多的大型企业参与；生物质能产业必将成为中国国民经济新的增长点。     

生物液体燃料可持续发展评价系统

该文分析了国内外生物液体燃料能量平衡研究现状。在综合考虑能量平衡、污染物排放、土地、水资源成本等各种因素的基础上,基于线性规划法和电子数据表工具（SPREADSHEET）,利用生命周期理论研究开发了生物液体燃料可持续评价系统（BSAS）,该系统主要有基础数据库、分析模块和优化模块3部分组成,以中国内蒙古和黑龙江两地发展甜高粱茎秆燃料乙醇为案例,利用该系统进行了可持续性评价。研究表明,利用该系统可实现国家、省以及特定地区等多个层面对发展生物液体燃料的可持续性进行优化分析和综合评价,得出选定地区在满足设定情景条件下优化的生物液体燃料产业发展规划,为政府部门科学决策提供技术支撑。     

小球藻粉水热催化液化制备生物油

为探索新型生物质燃油的开发,该文以小球藻粉为原料,采用水热催化液化方法制备生物油。研究了液化温度,液化时间,催化剂等因素对液化率的影响,在此基础上采用正交试验,以液化率为指标,探讨了生物油优化的制备工艺;利用傅里叶红外光谱(FTIR)和气相色谱-质谱联用(GC/MS)技术分析了小球藻粉生物油的基团结构与组成。结果表明,小球藻粉优化的液化反应条件为:采用质量分数5%的Ce/HZSM-5为催化剂,在300°C水热条件下催化液化20min,小球藻粉和溶剂料液比为1:10g/mL,液化率达39.87%。在此条件下制备的小球藻粉生物油的主要成分为醇类,酯类以及部分碳氢化合物,热值达26.09MJ/kg。和传统木质纤维素类生物质相比,小球藻粉制备的生物油成分更接近传统化石燃油且热值更高,显示了良好的应用前景,为微藻生物质液体燃料的制备提供参考。     

废弃生物质材料的高附加值再利用途径综述

现代工业的发展在促进人类社会物质文明繁荣的同时,导致了大量生物质资源的浪费。随着环境、能源等问题日益突出,废弃生物质资源的再利用研究越来越受到关注。该文在介绍废弃生物质材料丰富来源与传统处理方法的基础上,根据近几年的研究现状及发展趋势,就其循环利用途径进行了详细综述。废弃生物质材料主要来源于农业生产废弃物、农副产品与食品加工废弃物、林业与城市绿化废弃物及生活垃圾。废弃生物质材料的处理已经从传统方法(包括燃烧法、饲料化、肥料化与基质化处理),逐步走向能源化、生态化、材料改性,以及制备基于生物炼制技术的新型生物基功能与智能材料产品。总之,以废弃生物质材料为主要原料,开发新型基质与功能材料是发展趋势。     

陕西省生态环境现状及防治对策

从水土流失、土地荒漠化、水资源、工业污染等几个方面对陕西省生态环境现状进行了初步分析 ,通过分析大量数据指出了制约陕西省经济社会发展的因素之所在。同时 ,针对陕西省目前的生态环境现状 ,从调整土地利用结构 ,发展生态产业 ;加强水资源管理 ,建立节水社会 ;加速林草建设 ,保护生物资源 ;优化城乡能源结构 ,优化工业和城镇布局 ;建立环境影响评价制度 ;建立健全环境法律法规政策 ;从加速环境科学技术研究等方面对改善和促进陕西省环境状况 ,加速经济发展提出了对策     

《农业工程学报》:对标一流,追求卓越

正《农业工程学报》(以下简称《学报》)创刊于1985年,现为半月刊,全年24期,大16开面向国内外公开发行。《学报》是由中国科学技术协会主管、中国农业工程学会主办的全国性专业学术期刊。读者对象为农业工程学科及相关领域的科研、教学及生产科技人员、技术管理及推广人员和高等院校师生。刊稿内容涵盖了农业装备工程与机械化、农业航空工程、农业水土工程、农业信息与电气技术、农业生物环境与能源工程、土地保障与生态安全、农产品加工工程等学科专业领域。     

《农业工程学报》:对标一流,追求卓越

正《农业工程学报》(以下简称《学报》)创刊于1985年,现为半月刊,全年24期,大16开面向国内外公开发行。《学报》是由中国科学技术协会主管、中国农业工程学会主办的全国性专业学术期刊。读者对象为农业工程学科及相关领域的科研、教学及生产科技人员、技术管理及推广人员和高等院校师生。刊稿内容涵盖了农业装备工程与机械化、农业航空工程、农业水土工程、农业信息与电气技术、农业生物环境与能源工程、土地保障与生态安全、农产品加工工程等学科专业领域。     

《农业工程学报》:对标一流,追求卓越

正《农业工程学报》(以下简称《学报》)创刊于1985年,现为半月刊,全年24期,大16开面向国内外公开发行。《学报》是由中国科学技术协会主管、中国农业工程学会主办的全国性专业学术期刊。读者对象为农业工程学科及相关领域的科研、教学及生产科技人员、技术管理及推广人员和高等院校师生。刊稿内容涵盖了农业装备工程与机械化、农业航空工程、农业水土工程、农业信息与电气技术、农业生物环境与能源工程、土地保障与生态安全、农产品加工工程等学科专业领域。     

Biofuels, biodiversity, and people: Understanding the conflicts and finding opportunities

The finitude of fossil fuels, concerns for energy security and the need to respond to climate change have led to growing worldwide interests in biofuels. Biofuels are viewed by many policy makers as a key to reducing reliance on foreign oil, lowering emissions of greenhouse gases and meeting rural development goals. However, political and public support for biofuels has recently been undermined due to environmental and food security concerns, and by reports questioning the rationale that biofuels substantially reduce carbon emissions. We discuss the promise of biofuels as a renewable energy source; critically evaluate the environmental and societal costs of biofuel use; and highlight on-going developments in biofuel feedstock selection and production technologies. We highlight net positive greenhouse gases emissions, threats to forests and biodiversity, food price increases, and competition for water resources as the key negative impacts of biofuel use. We also show that some of these environmental and societal costs may be ameliorated or reversed with the development and use of next generation biofuel feedstocks (e.g., waste biomass) and production technologies (e.g., pyrolysis). We conclude that certain types of biofuels do represent potential sources of alternative energy, but their use needs to be tempered with a comprehensive assessment of their environmental impacts. Together with increased energy conservation, efficiencies and technologies such as solar-power and wind turbines, biofuels should be included in a diverse portfolio of renewable energy sources to reduce our dependence on the planet’s finite supply of fossil fuels and to insure a sustainable future.     

Future Testing Opportunities to Ensure Sustainability of the Biofuels Industry

For the soil and plant analysis community, development and expansion of biofuels will create many opportunities to provide a wide variety of analytical services. Our objective is to explore potential areas where those services could be marketed to support sustainable development of biofuels. One of the first is to provide soil fertility and plant nutrition information for sustainable feedstock production. Chemical, physical, and biological indicators of soil quality should also be monitored and interpreted using tools such as the soil management assessment framework (SMAF) to ensure soil resources can continue to meet global food, feed, and fiber demands as well as the new demands for biofuels. Feedstock sugar profile information will be needed to help manage conversion processes, calculate economic drivers such as the minimum ethanol selling price (MESP), and determine suitability for other bioproducts. There will also be an increasing need to evaluate a variety of coproducts created by corn (Zea mays) milling, soybean (Glycine max Merr.) processing, and the fledgling lignocellulosic conversion processes. For coproducts produced from wet or dry corn milling and dry grind ethanol production, accurate and efficient analysis and digestibility of fiber components [neutral detergent fiber (NDF), acid detergent fiber (ADF), and total dietary fiber (TDF)], amino acids (lysine, trypotophan, and methionine), fatty acids, and minerals (phosphorus and sulfur) will be needed. In addition, a capacity to accurately and rapidly detect contamination by mycotoxins such as aflatoxin, zearalenone, and fumonisisn or the presence of antibiotics such as penicillin or virginiamycin could potentially be important. For the biodiesel industry, methanol concentrations in crude glycerin must be reduced to meet Food and Drug Administration guidelines and quantified to ensure this coproduct is safe for use in livestock feeds. Finally, monitoring for several processes and coproducts associated with pyrolysis, a thermochemical platform for biomass conversion to bio-oils, biochar, and other products will be needed. We conclude that sustainable development of biofuel industries will have many positive benefits for soils, plant, and animal production systems and the analysts who will provide analytical services for monitoring all aspects of the biofuels industry.     

Efficient sugar release by the cellulose solvent-based lignocellulose fractionation technology and enzymatic cellulose hydrolysis

Efficient liberation of fermentable soluble sugars from lignocellulosic biomass waste not only decreases solid waste handling but also produces value-added biofuels and biobased products. Industrial hemp, a special economic crop, is cultivated for its high-quality fibers and high-value seed oil, but its hollow stalk cords (hurds) are a cellulosic waste. The cellulose-solvent-based lignocellulose fractionation (CSLF) technology has been developed to separate lignocellulose components under modest reaction conditions (Zhang, Y.-H. P.; Ding, S.-Y.; Mielenz, J. R.; Elander, R.; Laser, M.; Himmel, M.; McMillan, J. D.; Lynd, L. R. Biotechnol. Bioeng. 2007, 97 (2), 214- 223). Three pretreatment conditions (acid concentration, reaction temperature, and reaction time) were investigated to treat industrial hemp hurds for a maximal sugar release: a combinatorial result of a maximal retention of solid cellulose and a maximal enzymatic cellulose hydrolysis. At the best treatment condition (84.0% H3PO4 at 50 degrees C for 60 min), the glucan digestibility was 96% at hour 24 at a cellulase loading of 15 filter paper units of cellulase per gram of glucan. The scanning electron microscopic images were presented for the CSLF-pretreated biomass for the first time, suggesting that CSLF can completely destruct the plant cell-wall structure, in a good agreement with the highest enzymatic cellulose digestibility and fastest hydrolysis rate. It was found that phosphoric acid only above a critical concentration (83%) with a sufficient reaction time can efficiently disrupt recalcitrant lignocellulose structures.     

Effect of Decorticating Sorghum on Ethanol Production and Composition of DDGS

The use of a renewable biomass that contains considerable amounts of starch and cellulose could provide a sugar platform for the production of numerous bioproducts. Pretreatment technologies have been developed to increase the bioconversion rate for both starch and cellulosic‐based biomass. This study investigated the effect of decortication as a pretreatment method on ethanol production from sorghum, as well as investigating its impact on quality of distillers' dry grains with solubles (DDGS). Eight sorghum hybrids with 0, 10, and 20% of their outer layers removed were used as raw materials for ethanol production. The decorticated samples were fermented to ethanol using Saccharomyces cerevisiae. Removal of germ and fiber before fermentation allowed for greater starch loading for ethanol fermentation and resulted in increased ethanol production. Ethanol yields increased as the percentage of decortication increased. The decortication process resulted in DDGS with higher protein content and lower fiber content, which may improve the feed quality.     

生物质气化气发酵生产乙醇优良菌株的筛选

利用农业废弃物合成气发酵生产燃料乙醇不仅可以缓解中国的能源危机,也是减轻环境污染、促进农业可持续发展和改善农村环境的重要举措。该文对实验室富集获得的4个菌系及国内外报道较多的4个菌株发酵生物质合成气生产燃料乙醇的潜力进行了研究。结果表明:菌株LP-fm4、Clostridium sp.P11和A-fm4发酵生物质合成气生产乙醇的净产量分别为179.23、152.92和115.08 mg/L;菌体比生长速率分别为1.46、1.66和1.18d~(-1);乙醇比生成速率分别3.50、2.05和0.78d~(-1),单位菌体生成乙醇的量分别为2252.90、1450.20和1132.37 mg/g,显著高于其他菌株(群)。多重比较分析与综合性状聚类分析结果表明前两者为利用合成气高效发酵乙醇的理想菌体,菌A-fm4为具有潜力菌体。以期为未来农业废弃物合成气乙醇发酵提供了优良的菌种资源。     

Agricultural chemistry and bioenergy

Renewed interest in converting biomass to biofuels such as ethanol, other forms of bioenergy, and bioenergy byproducts or coproducts of commercial value opens opportunities for chemists, including agricultural chemists and related disciplines. Applications include feedstock characterization and quantification of structural changes resulting from genetic modification and of the intermediates formed during enzymatic and chemical processing; development of improved processes for utilizing chemical coproducts such as lactic acid and glycerol; development of alternative biofuels such as methanol, butanol, and hydrogen; and ways to reduce greenhouse gas emission and/or use carbon dioxide beneficially. Chemists will also be heavily involved in detailing the phytochemical composition of alternative energy crops and genetically improved crops. A resurgence of demand for agricultural chemistry and related disciplines argues for increasing output through targeted programs and on-the-job training.     

中国生物质固体成型燃料CDM项目开发

为了促进中国生物质固体成型燃料CDM项目的开发,该文以北京市某生物质固体成型燃料生产厂为例,利用小规模方法学AMS.I.C“有无发电的用户热能利用”及其他相关方法学,通过确定项目边界、设定基准线情景和主要参数,进行生物质固体成型燃料小型CDM项目开发,并制定了监测计划.结果表明,年生产1万t生物质固体成型燃料厂,温室气体减排量为13 688.22t/a,减排潜力较大.这表明该领域进行CDM项目开发具有较好的可行性,对中国实现温室气体减排目标具有重要的意义.     

木质纤维素酸催化制备糠醛的工艺及机理研究进展

糠醛是一种重要的生物质基平台化合物,国内外学者针对生物质产糠醛展开诸多研究,尤其是酸催化水解领域。该文综述了糠醛制备工艺在不同时期的情况,阐述并评价了目前新颖的同步产糠醛与纤维素基化学品工艺。对酸(稀布朗斯特酸和路易斯金属盐)催化木糖和半纤维素的反应动力学进行系统归纳,并阐述了相关机理的研究进展。最后,对现在研究热点——酸/有机溶剂作用体系中有机溶剂的作用机制进行归纳,并对计算化学在其中的最新研究情况进行总结。该文旨在为学者开展生物质产糠醛的研究提供信息,有利于学者进行选择性研究。     

Enzyme production by wood-rot and soft-rot fungi cultivated on corn fiber followed by simultaneous saccharification and fermentation

This research aims at developing a biorefinery platform to convert lignocellulosic corn fiber into fermentable sugars at a moderate temperature (37 °C) with minimal use of chemicals. White-rot (Phanerochaete chrysosporium), brown-rot (Gloeophyllum trabeum), and soft-rot (Trichoderma reesei) fungi were used for in situ enzyme production to hydrolyze cellulosic and hemicellulosic components of corn fiber into fermentable sugars. Solid-substrate fermentation of corn fiber by either white- or brown-rot fungi followed by simultaneous saccharification and fermentation (SSF) with coculture of Saccharomyces cerevisiae has shown a possibility of enhancing wood rot saccharification of corn fiber for ethanol fermentation. The laboratory-scale fungal saccharification and fermentation process incorporated in situ cellulolytic enzyme induction, which enhanced overall enzymatic hydrolysis of hemi/cellulose components of corn fiber into simple sugars (mono-, di-, and trisaccharides). The yeast fermentation of the hydrolyzate yielded 7.8, 8.6, and 4.9 g ethanol per 100 g corn fiber when saccharified with the white-, brown-, and soft-rot fungi, respectively. The highest ethanol yield (8.6 g ethanol per 100 g initial corn fiber) is equivalent to 35% of the theoretical ethanol yield from starch and cellulose in corn fiber. This research has significant commercial potential to increase net ethanol production per bushel of corn through the utilization of corn fiber. There is also a great research opportunity to evaluate the remaining biomass residue (enriched with fungal protein) as animal feed.