一种生物柴油生产体系的能值分析及新能值指标的构建

Emergy Evaluation of a Kind of Biodiesel Production System and Construction of New Emergy Indices

对一种以植物油为原料采用酯交换离心机分离连续生产生物柴油的CD-工艺方法生产生物柴油的体系进行了能值分析.该系统产出的生物柴油能值转换率为(8.60E+05)seJ/J,该结果验证了在目前条件下自然过程的能源生产效率要高于工业过程的观点.但笔者认为传统能源的能值转换率会增大,而新能源的会减小,两者会越来越接近.针对新能源生产的特点,构建了能值补益率(EAR,emergyassisted ratio)、可再生能值率(RER,reproducible emergy ratio)和温室气体能值率(GGER,greenhousegas emergy ratio)等3个新指标,其中能值补益率等于政府(或非政府组织)补贴货币的能值除以总产出能值,该值用来衡量政府(或非政府组织)对该产业的扶植力度;可再生能值率的数学表达式为RER=(ESR×EYR)/(EIR×ELR),用来衡量系统可再生性;温室气体能值率的数学表达式为GGER=(碳税×碳量×货币能值)/燃料能值,用来衡量燃料燃烧后对大气中温室气体能值的贡献率,该三项指标分别为0.65、0.06和0.13,生物柴油的温室气体能值率仅为石化柴油的1/5左右,非常有利于减小温室效应.原有能值指标体系中能值投资率(EIR,emergy invest ment ratio)、环境负荷率(ELR,environmentload ratio)、净能值产出率(EYR,emergy yield ratio)和能值自给率(ESR,emergy self-support ratio)等4项分别为3.57、3.55、3.68和0.22,前3项指标均明显优于生物乙醇生产系统,说明该生物柴油生产系统具有相当大的优势.随着生物柴油生产系统产能的扩大和优化,环境负荷率等指标会进一步降低,系统的可再生性会日益明显,最后从能值角度对生物柴油的其他优点进行了阐述.

This paper evaluated the emergy of a kind of biodiesel production system, whose raw material was obtained from vegetable oil by transesterification and separation with CD technology. The transformity of biodiesel was up to 8. 60E＋05seJ/J, which validated the fact that natural processes were more efficient than industrial ones. We thought that the transformity of traditional energy would increase while that of new energy would decrease, and these two transformities will be much closer. Emergy assisted ratio （EAR）, reproducible emergy ratio （RER） and greenhouse gas emergy ratio （GGER） were constructed as three new emergy indices according to the new energy production. EAR equaled to emergy of money from government or non-government organization divided by total emergy output, which measured the support by government or non-government organization. The equation of RER： RER=（ESR×EYR）/（EIR×ELR） measured the reproducibility of the system. The equation of GGER： GGER= （carbon tax× carbon× money emergy）/fuel emergy measured the contribution of greenhouse gas in the perspective of emergy after combustion. The values of three indices were 0. 65, 0. 06 and 0. 13, and GGER of biodiesel only equaled to one fifth of that of diesel. Biodiesel contributed to the decrease of greenhouse effect. Emergy investment ratio （EIR）, environment load ratio （F.LR）, emergy yield ratio （EYR） and emergy self-support ratio （ESR） of biodiesel were 3. 57, 3. 55, 3. 68 and 0. 22, the former three of which were better than those of bioethnaol. This indicated that the biodiesel system was relatively better in this sense. Some indices of biodiesel such as ELR would decrease further and the reproducibility would become gradually obvious during the enlargement and optimization of the system. Finally, some other advantages of biodiesel were also illustrated in the perspective of emergy.