Improving ethanol life cycle energy efficiency by direct utilization of wet ethanol in HCCI engines
Improving ethanol life cycle energy efficiency by direct utilization of wet ethanol in HCCI engines
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DOI：
10.1115/1.2794768
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发表时间：
2007-12-01
影响因子：
3
通讯作者：
Flowers, Daniel L.
中科院分区：
文献类型：
--
作者：
Martinez-Frias, Joel;Aceves, Salvador M.;Flowers, Daniel L.
均质充量压燃（HCCI）是一种新型的发动机技术，与传统发动机有着根本的区别。HCCI发动机本质上是燃料灵活的，并且只要燃料可以被加热到点火点，就可以在低级燃料上运行。特别地，HCCI发动机可以在“湿乙醇“上运行：具有高浓度水的水包乙醇混合物。考虑到加工发酵乙醇所需的大部分能量都花费在蒸馏和脱水中，在HCCI发动机中直接使用湿乙醇显著地改变了能量平衡，有利于乙醇。该论文的结果表明，具有有效热回收的HCCI发动机可以在35%乙醇和65%水的混合物上运行，同时实现高制动热效率（38.7%）和非常低的NOx（1.6 ppm，足够清洁以满足任何现有或即将到来的排放标准）。直接利用体积分数为35%的乙醇可将水分离成本降低到仅为乙醇和副产物能量的3%（而生产纯乙醇为37%），并将净能量增益从乙醇和副产物能量的21%提高到55%。湿乙醇利用是一个有前途的概念，值得更详细的分析和实验评估。
Homogeneous charge compression ignition (HCCI) is a new engine technology with fundamental differences over conventional engines. HCCI engines are intrinsically fuel flexible and can run on low-grade fuels as long as the fuel can be heated to the point of ignition. In particular HCCI engines can run on "wet ethanol:" ethanol-in-water mixtures with high concentration of water Considering that much of the energy required for processing fermented ethanol is spent in distillation and dehydration, direct use of wet ethanol in HCCI engines considerably shifts the energy balance in favor of ethanol. The results of the paper show that a HCCI engine with efficient heat recovery can operate on a mixture of 35% ethanol and 65% water by volume while achieving a high brake thermal efficiency (38.7%) and very low NOx (1.6 ppm, clean enough to meet any existing or oncoming emissions standards). Direct utilization of ethanol at a 35% volume fraction reduces water separation cost to only 3% of the energy of ethanol and coproducts (versus 37% for producing pure ethanol) and improves the net energy gain from 21% to 55% of the energy of ethanol and coproducts. Wet ethanol utilization is a promising concept that merits more detailed analysis and experimental evaluation.