乙醇和二甲醚在激波管内的裂解试验与动力学研究

Pyrolysis Experiment and Kinetics Study of Ethanol and Dimethyl Ether in Shock Tube

为探究含氧燃料在高温低压条件下的裂解特性,以乙醇和二甲醚为研究对象,利用激波管开展了两种燃料的裂解试验,通过气相色谱仪测量了乙醇和二甲醚在1200~1700 K和0.20~0.25 MPa条件下4种热解产物甲烷、乙炔、乙烯和甲醛的浓度,利用直接关系图法构建了详细的组合简化模型(DME-Ethanol模型),并通过该模型进行产率和敏感性分析。结果表明:乙醇和二甲醚热解过程中的主要产物分别为乙烯和甲烷;乙醇和二甲醚在热解过程中均主要是通过由H和CH 3自由基等引发的夺氢反应消耗,二甲醚中特有的对称结构使得其通过单分子解离反应消耗的比例大于乙醇,更多的甲基增大了二甲醚热解体系的反应性;DME-Ethanol模型对两种燃料裂解产物的浓度预测误差在10%以内。

In order to explore the pyrolysis characteristics of oxygenated fuels under high temperature and low pressure conditions, ethanol and dimethyl ether(DME) were used as the research objects in shock tubes to conduct the pyrolysis experiment. The concentrations of four pyrolysis products of methane, acetylene, ethylene and formaldehyde in ethanol and dimethyl ether pyrolysis at 1 200-1 700 K and 0.20-0.25 MPa were tested by gas chromatograph. Also, direct relationship graph method was used to establish a detailed, combined and simplified model(DME-Ethanol model), then ROP analysis and sensitivity analysis were performed. The results show that dimethyl ether and ethanol are mainly consumed by the H-abstraction reactions initiated by H and CH_(3), etc.;the proportion of dimethyl ether consumed by unimolecular dissociation reactions is larger than that of ethanol due to its unique symmetrical structure. More methyl groups increase the reactivity of dimethyl ether pyrolysis. The concentration prediction errors of the DME-Ethanol model for the pyrolysis products are within 10%.