前脱乙烷分离流程在乙烯装置中应用的分析研究

Analysis and Research on Application of Front End Deethanizer Separation Process in Ethylene Plant

介绍了乙烯装置的几种分离流程,以及乙烯装置中各区的作用,依据裂解原料为丙烷、正丁烷和轻石脑油设计了三类(五种)前脱乙烷工艺流程,分别是脱乙烷塔在裂解气压缩机五段出口(包括两种流程:乙炔加氢在脱乙烷塔回流罐之后、乙炔加氢在脱乙烷塔与其回流罐之间)、脱乙烷塔在裂解气压缩机四五段间、取消液相干燥器(包括两种流程:低压脱乙烷塔改为凝液汽提塔、液相返回至压缩机段间吸入罐),并分析了几种工艺流程的特点。基于流程模拟软件PRO-Ⅱ9.2对这五种工艺流程进行了全流程模拟,分析了塔操作参数、冷剂用户热负荷、三机功率、塔设备尺寸。结果表明,从能耗、操作稳定性和简易性、设备投资等角度考虑,各工艺流程各有优缺点:第一种流程的三机总功率最低;第二种流程的乙炔加氢系统操作稳定性好,但三机总功率增大;第三种流程省去了低压脱乙烷塔系统的投资,但三机总功率较高;第四种流程省去了液相干燥器系统,设备投资少、操作简易,三机总功率有所增大;第五种流程同样省去了液相干燥系统,设备投资少、操作简易,但三机总功率增加十分明显。

Several separation processes for ethylene plant and the functions of each area in ethylene plant are introduced.For pyrolysis raw materials of propane,n-butane and light naphtha,three types(five kinds) of front end deethanizer process are designed,i.e.the process with deethanizer at the 5 th-stage outlet of cracked gas compressor( the acetylene hydrogenation is downstream the deethanizer reflux drum,or the acetylene hydrogenation is between the deethanizer and its reflux drum),the process with deethanizer between the 4 th stage and the 5 th stage of cracked gas compressor, and the process without liquid dryer( the low pressure deethanizer is replaced by condensate stripper,or the liquid returns to the suction drum of cracked gas compressor).And the characteristics of these processes are analyzed.Based on the process simulation software Pro-Ⅱ 9.2,whole process simulation is carried out for these five processes,and the operation parameters of towers,the heat load of refrigerant users,the power of the three compressors and the size of tower equipment are analyzed.The results show that each process has its advantages and disadvantages from the perspectives of energy consumption,operation stability and simplicity,and equipment investment.The total power of the three compressors in the first process is the lowest;the second process has good operation stability of acetylene hydrogenation system,but the total power of the three compressors is higher;the third process saves the investment of low pressure deethanizer system,but the total power of the three compressors is high;the fourth process has lower equipment investment and easy operation because liquid dryer system is eliminated,but the total power of the three compressors increases to some extent;the fifth process also has lower equipment investment and easy operation because liquid dryer system is eliminated,but the total power of the three compressors increases obviously.