中粮40万t木薯乙醇燃料项目开工

我国以非粮作物为原料生产清洁汽油项目获得突破，由中粮集团投资百亿元建设的40万t木薯乙醇燃料项目1期工程近日在广西百色开工建设。它标志着我国最大的粮食加工企业——中粮集团开始进入新能源生产领域。加工1t燃料乙醇。用木薯比用玉米和甘蔗成本分别低500元和300元左右。     

中国燃料乙醇的应用及生产技术的效益分析与评价

针对国内外燃料乙醇的应用和发展情况,对比分析了淀粉质、糖质和纤维素类原料燃料乙醇生产工艺的异同,并对我国3种原料的资源状况进行了评价.以10万t/a的燃料乙醇工厂为例,对不同原料燃料乙醇生产工艺的经济性、能源效益和社会效益进行了对比分析,发现甜高梁和木薯最有经济优势;从能源效益分析可知生产工艺能耗约占80%,工艺改进非常重要;从单位土地能源净产出情况看,甜高梁最高,其次是甘蔗和木薯,可见能源作物具有开发潜力;通过社会效益分析,10万t燃料乙醇工厂会给农民带来2～4亿元的年收益,提供约1000个的就业岗位;且10万t燃料乙醇的应用CO2年减排量可达30万t以上,减排CO、CH等汽车有害污染物近1700t.     

广西将建30万t燃料乙醇工厂

中国粮油控股有限公司今年年内将在广西建设年产能30万t燃料乙醇Ⅱ期项目，该项目仍以木薯为原料，估计总投资额达12~13亿元人民币，这将成为自去年年初以来中国首个获批的燃料乙醇项目。     

我国发展甘蔗燃料乙醇的战略思考

甘蔗和木薯是热带、亚热带作物,对山坡地、沙洲地和盐碱地等边际性土地有较强的适应性,在蔗糖主产区广西、云南、广东、海南等地广泛种植。木薯燃料乙醇面临原料供应不足、价格上涨的问题。文章分析了以甘蔗作为燃料乙醇原料具有的优势,同时对我国长期食糖需求及支撑食糖需求的土地潜力进行了研究。研究表明,与木薯原料相比,以甘蔗原料生产燃料乙醇具有单位土地面积产量高、综合利用价值高、节能减排效果好等优势,同时具有保护环境、稳定食糖价格等作用。只要食糖价格合理,在保证我国粮食安全与食糖安全的前提下,通过实施间套种技术,近期可以实现100万t甘蔗燃料乙醇的产能,远期的产能目标为200万～300万t。     

我国燃料乙醇原料可持续供应初步分析

本文通过评价我国粮食供应形势、土地资源、农业生产的特点,资源禀赋等,对我国燃料乙醇原料供应进行了初步分析。我国人多地少,耕地资源紧缺,粮食供需处于紧平衡,以玉米为原料的燃料乙醇发展空间受到极大的限制,原料多元化势在必行。初步测算,2010年燃料乙醇的可供应量约360万t,2020年燃料乙醇的可供应量约1700万t,可以满足国家可再生能源中长期发展规划规定的目标。最后,提出依靠科技进步以及发展纤维素乙醇等措施。     

4种能源植物在中国的适应性及液体燃料生产潜力评估

利用气象数据评价边际性土地种植能源植物甜高粱、木薯、柳枝稷和麻疯树的气候适宜性,估算液体生物燃料的生产潜力,并比较这4种能源植物的经济效益。结果表明,在集中连片宜耕边际性土地中,甜高粱、木薯、柳枝稷和麻疯树的适宜种植面积分别为218.65、18.82、208.67和46.19万hm2。甜高粱、木薯、柳枝稷燃料乙醇的生产潜力分别为648.82、23.85、633.63万t,麻疯树生物柴油的生产潜力为40.42万t。与柳枝稷和麻疯树相比,甜高粱和木薯的经济效益更高,更适宜边际性土地液体生物燃料生产,其利润分别为2940和1322$/hm2。     

燃料乙醇生命周期影响评价

建立了中国燃料乙醇生命周期影响评价模型,并以木薯燃料乙醇为例,对中国燃料乙醇进行了生命周期影响评价。结果表明：在木薯燃料乙醇生命周期过程中,“燃烧／车辆使用”产生的环境影响最大,占整个生命周期的51．82％;其次为“燃料生产”单元,占41．32％;“原料生产”单元仅占6．86％。随着木薯燃料乙醇在汽油中混合比例的增加,其生命周期环境影响总水平值降低。与汽油比较,木薯乙醇产生的环境影响较小。     

美国生物质能的发展状况及对我国的启示

2006年美国燃料乙醇产量为1 742万t,生物柴油产量90万t.2012年美国可再生燃料年利用量将增加到341亿L.美国发展生物质能主要目的是保护美国农民利益,通过政府引导,市场调节促进生物质能的产业发展;为了有效地规避风险,美国芝加哥期货交易所推出燃料乙醇期货.对我国的启示是,发展燃料乙醇不能照搬美国的模式,我国燃料乙醇要走多元化道路,政府要加大科研、开发的扶持力度,以及加强中美在生物质能领域的合作等.     

木薯乙醇-汽油混合燃料生命周期能源消耗多目标优化研究

建立了木薯乙醇—汽油混合燃料生命周期能源消耗单目标和多目标优化模型。以生命周期总体能源消耗、化石燃料消耗和石油消耗为优化目标，对木薯乙醇—汽油混合燃料生命周期能源消耗进行了单目标及多目标优化，并进行了灵敏度分析。结果表明：多目标优化能使木薯乙醇—汽油混合燃料的生命周期总体能源、化石燃料和石油消耗同时降低，可以为木薯乙醇—汽油混合燃料的应用提供决策依据，具有重要的应用价值。     

我国非粮燃料乙醇的原料资源量分析

目前世界燃料乙醇的生产原料约60%为甘蔗或甜菜等糖质原料、33%为玉米或小麦等淀粉质原料,而纤维质原料正日益受到重视。我国可用于生产燃料乙醇的非粮淀粉质原料主要有甘薯、木薯、蕉藕、葛根等。其中蕉藕目前尚未形成产业化生产;葛根原料价格高,不宜作为乙醇原料;甘薯归属粮食范畴;只有木薯是最适宜制燃料乙醇的非粮淀粉质原料。纤维质原料主要包括农作物秸秆、农林废弃物、木屑等,其中农作物秸秆是我国产量最大的非粮燃料乙醇原料。秸秆资源密度考虑,利用区域应主要集中在河南、山东、江苏等地,保守估计这3个省的秸秆量可供生产1117×104t乙醇。目前制约纤维质原料制乙醇的关键瓶颈之一是原料的收集、运输及供应保障,若没有国家大的政策扶持和资金补贴,纤维质原料因缺乏经济可行性而尚不具备工业化生产乙醇的条件。糖质原料主要有甘蔗、甜菜、甜高粱茎秆和菊芋。由于菊芋菊粉附加值高,不宜作乙醇原料;甘蔗、甜菜主要用于糖业,不会作为乙醇原料;从单位土地面积乙醇产量和原料成本、农民种植收益综合来看,甜高粱茎秆是适宜生产燃料乙醇的糖质原料。需要寻求产业化种植模式来落实资源总量,提高资源保障度;另一方面要进一步研究低成本、安全保质的茎秆储藏技术。     

木薯乙醇汽油生命周期能源、环境及经济性评价

建立了木薯乙醇汽油生命周期能源、环境和经济性评价模型，并对木薯乙醇汽油进行了生命周期能源、环境及经济性评价。结果表明：与普通汽油比较，木薯乙醇汽油生命周期整体能源消耗升高，石油消耗降低；生命周期温室气体、VOC和CO等污染物排放降低；销售价格升高并需要政府补贴。从平衡生命周期能源消耗、环境排放和经济性角度出发，木薯乙醇汽油可以在广西推广使用。     

Simulation-based life cycle assessment of energy efficiency of biomass-based ethanol fuel from different feedstocks in China

Interests in biomass-based fuel ethanol (BFE) have been re-boosted due to oil shortage and environmental deterioration. Biomass-based fuel ethanol is renewable and, apparently, environmentally friendly. Biomass-based E10 (a blend of 10% ethanol and 90% gasoline by volume) is a promising conventional gasoline substitute, because vehicle engines require no modifications to run on E10 and vehicle warranties are unaffected. This paper presented life cycle assessments (LCAs) of energy efficiency of wheat-based E10 from central China, corn-based E10 from northeast China, and cassava-based E10 from southwest China. The respective energy flow-based evaluation model of wheat-, corn-, and cassava-based E10 was built based on data from pilot BFE plants. Monte Carlo method is applied to deal with the uncertain parameters and input and output variables of the evaluation model because of its wide application and easy development of statistical dispersion of calculated quantities. According to the assessment results, the average energy input/output ratio of wheat-based fuel ethanol (WFE), corn-based fuel ethanol (CFE), and cassava-based fuel ethanol (KFE) is 0.70, 0.75, and 0.54, respectively, and biomass-based E10 vehicle can have less fossil energy demand than gasoline-fueled ones.     

考虑可再生性的燃料生命周期净能源成本优化

提出了一个新的考虑燃料可再生性的净能源成本指标.这一指标除了燃料的净能源产出和气态污染物排放外部成本之外,还将生命周期成本和燃料可再生性综合成一个指标,而已往的研究一般仅考虑前两项.以广西木薯-汽油混合燃料考虑可再生性的生命周期净能源成本优化为案例,对木薯乙醇-汽油混合燃料考虑可再生性的生命周期净能源成本指标进行了优化.结果表明：与初始值相比,优化后该指标值降低6.9%.     

Emergy analysis of cassava-based fuel ethanol in China

Emergy analysis considers both energy quality and energy used in the past, and compensates for the inability of money to value non-market inputs in an objective manner. Its common unit allows all resources to be compared on a fair basis. As feedstock for fuel ethanol, cassava has some advantages over other feedstocks. The production system of cassava-based fuel ethanol (CFE) was evaluated by emergy analysis. The emergy indices for the system of cassava-based fuel ethanol (CFE) are as follows: transformity is 1.10 E + 5 sej/J, EYR is 1.07, ELR is 2.55, RER is 0.28, and ESI is 0.42. Compared with the emergy indices of wheat ethanol and corn ethanol, CFE is the most sustainable. CFE is a good alternative to substitute for oil in China. Non-renewable purchased emergy accounts for 71.15% of the whole input emergy. The dependence on non-renewable energy increases environmental degradation, making the system less sustainable relative to systems more dependent on renewable energies. For sustainable development, it is vital to reduce the consumption of non-renewable energy in the production of CFE.     

Multi-objective optimization of cassava-based fuel ethanol used as an alternative automotive fuel in Guangxi,China

Multi-objective optimization of net energy, external costs of environment pollutant-emissions, and cost of using cassava-based fuel ethanol as an alternative automotive fuel in Guangxi has been conducted based on its holistic life cycle, from feedstock production to fuel combustion. A new indicator, cost of net energy (CNE), linking net energy-yield, external cost of environment pollutant-emissions, and production cost (the lower the CNE reading, the better the total performance) of ethanol–gasoline blends, is proposed for carrying out multi-objective optimization. On the life-cycle basis, CNE of ethanol–gasoline blends is found to obtain its lowest value, i.e. 0.119  RMB/MJ, when processing fuel during the ethanol conversion stage was natural gas and the ratio of ethanol blended with gasoline was 5%. From the standpoint of the CNE indicator, the most viable implement form of cassava-based fuel ethanol should be used as one of oxygenate additives. The recommended processing fuel during ethanol conversion stage should be natural gas.     

考虑可再生性的全生命周期净能源成本评估方法研究

提出了一个新的考虑燃料可再生性的净能源成本指标。这一指标将燃料的净能源产出、气态污染物排放外部成本、生命周期成本和能源可再生性综合成一个统一的指标，燃料指标值越低表明燃料的总体表现越好。运用该指标对木薯乙醇——汽油混合燃料和传统汽油燃料分别进行了评估。结果表明与分别评价燃料的净能源产出、生命周期成本、排放和可再生性指标比较，为考虑燃料的可再生性的全生命周期净能源成本指标提供了一个区别燃料优劣的有力手段。     

Energy and greenhouse gas balances of cassava-based ethanol

Biofuel production has been promoted to save fossil fuels and reduce greenhouse gas (GHG) emissions. However, there have been concerns about the potential of biofuel to improve energy efficiency and mitigate climate change. This paper investigates energy efficiency and GHG emission saving of cassava-based ethanol as energy for transportation. Energy and GHG balances are calculated for a functional unit of 1 km of road transportation using life-cycle assessment and considering effects of land use change (LUC). Based on a case study in Vietnam, the results show that the energy input for and GHG emissions from ethanol production are 0.93 MJ and 34.95 g carbon dioxide equivalent per megajoule of ethanol respectively. The use of E5 and E10 as a substitute for gasoline results in energy savings, provided that their fuel consumption in terms of liter per kilometer of transportation is not exceeding the consumption of gasoline per kilometer by more than 2.4% and 4.5% respectively. It will reduce GHG emissions, provided that the fuel consumption of E5 and E10 is not exceeding the consumption of gasoline per kilometer by more than 3.8% and 7.8% respectively. The quantitative effects depend on the efficiency in production and on the fuel efficiency of E5 and E10. The variations in results of energy input and GHG emissions in the ethanol production among studies are due to differences in coverage of effects of LUC, CO₂ photosynthesis of cassava, yields of cassava, energy efficiency in farming, and by-product analyses.     

Life cycle simulation-based economic and risk assessment of biomass-based fuel ethanol (BFE) projects in different feedstock planting areas

Increasing attention is being paid to biomass-based fuel ethanol (BFE) for its contributions to moderating oil crisis, reducing environmental impact, and promoting local economy. This paper aims to assess and compare the economic viabilities and investment risks of three BFE projects in different feedstock planting areas in China. Internal cost models of wheat-based fuel ethanol (WFE) in Central China, corn-based fuel ethanol (CFE) in Northeast China, and cassava-based fuel ethanol (KFE) in Southwest China are developed. The projects’ net cash flow (NCF) and net present values (NPV) are pursued by internal cost model simulation with the Monte Carlo method. According to the simulation results, KFE project is economically viable for its positive expected NPV and its expected internal rate of return (IRR) (12%), while CFE and WFE are not economically viable for their negative expected NPVs. Sensitivity analysis is performed to find out the key determinants of the projects’ expected NPVs and to evaluate their future economic viabilities. The analysis results indicate that CFE has better potential to become economically viable comparing to WFE project. Possible measures to improve the expected NPV of CFE are then proposed.