LNG轻烃分离与乙烯冷分冷量联合

Cold energy combination of LNG light hydrocarbon separation and ethylene plant

乙烯深冷分离过程需要冷剂为分离过程提供不同等级的冷量,可以把乙烯深冷分离过程作为一个冷阱;LNG气化过程中,需要加热,可以作为冷源。考虑到冷阱冷源的相互匹配,提出通过将LNG经过轻烃分离,为乙烯深冷分离提供冷量,降低了制冷公用工程消耗,同时LNG气化装置降低了加热公用工程消耗,且LNG分离出的轻烃直接供给乙烯装置作为裂解原料使用,优化乙烯装置裂解原料。以300万吨/年的LNG装置和64万吨/年的乙烯装置为例进行模拟计算得到,LNG轻烃分离装置可为乙烯冷分提供冷量41464 k W,降低乙烯冷分三元冷剂消耗75%,为乙烯装置提供优质裂解原料约65万吨/年。

Different level of cold energy is needed in the cryogenic separation process of an ethylene plant, so the ethylene separation process can be treated as a cold sink. Heat is needed in a LNG gasification process which can be treated as a cold source. This work combines the ethylene cryogenic separation process with the LNG gasification process, so that the cold utility demand in the ethylene cryogenic separation and the heat utility demand in the LNG gasification process are both reduced. The light hydrocarbons which get from LNG separation process can be a perfect cracking feed for the ethylene plant. A plant with a 3000000 t · a^-1 LNG process and a 640000 t · a^-1 ethylene process is used as a case study. The simulation results show that LNG plant can provide 41464 kW cold utility for the ethylene plant, reducing 75% refrigerant consumption of the ethylene plant. It also provides 650000 t · a^-1 high quality cracking feed for the ethylene plant.