通过热力学计算,得到各温度点下丁烯裂解/甲醇转化制乙烯、丙烯各主要反应的平衡常数和反应热,并分析了反应温度、原料组成对丁烯/甲醇耦合反应化学平衡的影响情况。计算结果表明,甲醇脱水转化成烃的平衡常数非常大,远高于丁烯裂解反应;丁烯裂解的产物分布受反应温度的影响程度大于甲醇转化和丁烯/甲醇耦合反应;在甲醇反应中引入丁烯,可提高乙烯(E)、丙烯(P)含量及丙烯与乙烯的摩尔比(np/nE),还可强化升温对甲醇反应的抑制作用;耦合反应中提高原料丁烯含量对甲醇转化有一定的促进作用,而且丁烯的裂化情况对乙烯、丙烯收率起到决定性作用,尤其是在高温条件下。
Equilibrium constants and reaction heats of several reactions of butene cracking and methanol conversion were obtained by thermodynamic calculation. Based on these data, the effect of temperature and composition of feed on the thermodynamic equilibrium for coupled conversion of butene and methanol was discussed. Results calculated showed that equilibrium constants of methanol dehydration to olefins were far larger than that of butene cracking reactions. The reaction temperature had more effect on product distribution of butene cracking than methanol conversion and coupled conversion of butene and methanol. The yields of ethylene and propylene and the mole ratio of propylene to ethylene may all increase, and the inhibiting force of increasing temperature to methanol dehydration was intensified, when butene was introduced into methanol conversion. In addition, it can be concluded that, for coupled conversion of butene and methanol, the conversion of methanol could be promoted by increasing the content of butene in feedstock, and butene played a crucial role in the enhancement of ethylene and propylene yields, especially at high temperature.