新节能脱甲烷系统

A new energy saving demethanization system

在某30万t乙烯装置低压脱甲烷系统的基础上,应用流程模拟技术开发出一套新的节能的脱甲烷系统。新系统在流程中引入膨胀机,有效避免了气体节流的能量损失;调整、优化了原有的工艺参数,减少了直接节流到塔压的裂解气量;对系统换热网络重新进行了匹配,更加合理利用了各股物料的冷量,使脱甲烷塔回流比、甲烷压缩机负荷以及乙烯冷剂消耗均有所降低。模拟结果表明,新系统总计节能达到1377 kW。

Based on an existing low pressure demethanization system of a 300 000 t/a ethylene plant, a new energy saving demethanization system was developed by using process simulation and optimization. Expanders were introduced in the chilling train to recover the energy of the high-pressure cracking gas. The existing process parameters were adjusted and optimized. The high-pressure cracking gas flowrate that was directly flashed to the demethanizer pressure was reduced. The heat exchanger network was rearranged, so that the energy utilization became more reasonable, which made the demethanizer reflux, the methane compressor power and the ethylene refrigerant consumption get all reduced. The simulation results indicate the total energy saving for the new system is 1 377 kW.