乙烯直接氯化制二氯乙烷的工艺分析

Process Analysis of the Direct Chlorination of Ethylene to Dichloroethane

采用300 m L反应釜进行乙烯直接氯化的实验,对低温、中温和高温氯化3种乙烯直接氯化工艺的二氯乙烷选择性和系统热负荷进行比较,考察Na Cl助催化剂用量和乙烯与氯气的分压比对二氯乙烷选择性的影响。实验结果表明,与低温氯化工艺相比,中温和高温氯化工艺二氯乙烷的选择性分别降低了约0.10%和0.25%,但系统热负荷与低温工艺相比从624.7 k J/h分别降至304.1 k J/h和265.2 k J/h;Na Cl助催化剂的加入可打破Fe Cl3的二聚体,当Na Cl与Fe Cl3的摩尔比为1∶3时能明显提高二氯乙烷的选择性;乙烯与氯气的分压比为1.25时,低温、中温和高温3种氯化工艺的二氯乙烷选择性分别可达到99.90%,99.86%,99.81%。

The direct chlorination of ethylene to dichloroethane was investigated in a 300 mL reactor. The influences of low temperature,medium temperature and high temperature on the selectivity of dichloroethane and the heat duty of the reaction system were studied. The effects of the NaCl cocatalyst dosage and partial pressure ratio of C2H4 to Cl2 on the selectivity were rearched. The results showed that,compared with the low temperature process,the selectivity to dichloroethane in the medium and high temperature processes decreased slightly by 0.10% and 0.25%,and the heat duty of the reaction system were reduced from 624.7 k J/h to 304.1 and 265.2 k J/h,respectively. The addition of the cocatalyst NaCl could break the dimer of Fe Cl3,which led to the signifi cant increase of the selectivity to dichloroehane at the molar ratio of NaCl to Fe Cl3 of 1∶3. When the partial pressure ratio of C2H4 to Cl2 was 1.25,the selectivities to dichloroethane in the three processes reached 99.90%,99.86% and 99.81%,respectively.