乙烯装置提高氢气回收率的研究

RESEARCH ON IMPROVING HYDROGEN RECOVERY OF ETHYLENE PLANT

某石化企业乙烯装置并联的2条激冷线实际运行状况与原设计偏差较大,脱甲烷塔各段进料分离罐温度、甲烷氢分离罐温度以及脱甲烷塔顶温度偏离设计值,冷箱各级温度较设计值高,导致氢气回收率低,纯度不达标等现象。研究分析结果表明:通过调节甲烷氢分离罐底低压CH_4的J-T阀(焦耳汤姆逊效应)背压,降低低压CH4尾气温度,提高尾气换热器冷热侧的温差和热负荷,可提高H_2的纯度和回收率。

The actual operation of two parallel chilling lines in an ethylene plant deviated a lot from the original design. The hydrogen recovery was low and the hydrogen purity could not meet the specification because the temperature in demethanizer feed separation drums, the temperature in methane and hydrogen separation drum and the demethanizer overhead temperature deviated from the design values and the temperatures in cold box were higher than the design value. The research results show that by adjusting the J-T( Joule-Thomson effect) valve back pressure of LP CH_4 at the bottom of methane and hydrogen separation drum, reducing the temperature of the LP CH_4,increasing the temperature difference between the hot and cold sides of heat exchanger and the thermalload of heat exchanger,the purity and recovery of hydrogen can be improved.