不合格碳二通过跨线液化后对丙烯制冷系统的影响

INFLUENCE OF LIQUEFIED OFF-SPEC C_2ON PROPYLENE REFRIGERATION SYSTEM

不合格碳二回收线投用后,乙烯液化90 t/h以下时,丙烯制冷压缩机三段丙烯蒸发量未增加,乙烯产品冷却器丙烯蒸发量57.1 t/h,乙烯产品过冷器丙烯蒸发量21.9 t/h,暂未超操作余量。4台裂解炉投料后乙烯液化量逐渐超110 t/h,严重超设计负荷,丙烯制冷压缩机一段、二段吸入流量大幅增加(一段流量上升比例较大)。一段、二段吸入流量增加造成一段、二段吸入压力偏高,三段丙烯蒸发量未发生明显变化。参照丙烯制冷压缩机各段设计工况成比例对比,压缩机一段、二段发生偏流。

When the off-spec C_2 recovery pipeline was put into use and the ethylene liquefaction capacity was below 90 t / h, the propylene evaporation in the 3rd section of propylene refrigeration compressor did not increase,and the propylene evaporation in ethylene cooler and ethylene subcooler were 57. 1 t / h and 21. 9 t /h respectively,not exceeding the operating margin. After four cracking furnaces were put into operation,the ethylene liquefaction capacity gradually exceeded 110 t / h,far beyond the design load,and the 1st and 2nd section suction flow of the propylene refrigeration compressor remarkably increased,while the increase in the 1st section suction flow was sharper. As a result,the 1st and 2nd section suction pressure was high. There was no significant change in the propylene evaporation in the 3rd section.Referring to the design conditions of the propylene refrigeration compressor,bias current occurred in both the 1st and 2nd section of the compressor.