Abstract: A demethanizer separation process under the condition of propylene as refrigerant for 1800kt/a methanol to olefin(MTO) unit was simulated and optimized using Aspen Plus software. It was calculated and compared with actual operation conditions by using RK-SOVE practical state equation and RadFrac module. The reliability of the model was verified. It was made a sensitivity analysis for feeding location，intercooler location and handling capacity，and emphatically investigated the influence of absorbent flowrate and its components on the separation efficiency. The results showed that the comprehensive effects of precut-demethanizer process were not obvious，although it improved the absorption-demethanizer process on the aspect of reducing ethylene loss and absorbent dosage. Sensitivity analysis showed that the optimal values existed for the examined variables except absorbent dosage of precut-demethanizer process.

Key words: methanol to olefin (MTO), demethanizer, separation, simulation, absorption

摘要： 采用Aspen Plus流程模拟软件对1800kt/a MTO装置的中冷脱甲烷塔分离过程进行模拟和优化。选用RK-SOVE状态方程和RadFrac模块进行计算并与实际工况进行对比，验证了模型的可靠性。并对进料位置、中间冷却器位置和处理量进行灵敏度分析，着重考察了吸收剂使用量及其组成对分离效果的影响。模拟结果表明，预切割-脱甲烷工艺虽然在降低乙烯损失和吸收剂用量方面对吸收?-脱甲烷工艺进行了改进，但是综合效果并不明显。灵敏度分析显示除预切割-脱甲烷工艺的吸收剂用量外，其余考察变量均存在最优值。

关键词: 甲醇制烯烃, 脱甲烷塔, 分离, 模拟, 吸收