乙烯脱轻塔精馏过程及安全事故动态模拟

Study on the rectifying process and safety accidents of the de-light ethylene fractionator through dynamic simulation

乙烯脱轻塔是高浓度乙烯精制过程中的关键设备,主要作用为脱除原料乙烯(>98 wt.%)中的少量轻组分杂质(CO,H_2,CH_4等),以达到后续醋酸乙烯合成工艺使用的标准。通过Aspen Plus软件对该乙烯脱轻塔进行稳态模拟,添加适当的设备参数后,导入Aspen Dynamics软件中。首先根据经验及相关文献为该塔设计动态控制方案,再改变进料流量、进料组成、冷凝量输入及再沸量输入等条件,模拟实际生产过程中可能发生的扰动,考察该方案是否可以保证该塔在适当的扰动范围内依然安全、合格的进行乙烯精制,并得到该脱轻塔运行过程的临界操作值,尝试提出预防安全事故发生的措施。通过该动态模拟,对乙烯脱轻塔的生产过程有了更符合实际扰动因素、工况的模拟,对实际的工厂操作过程有一定指导借鉴作用。

The de-light fractionator is the key equipment in high concentration ethylene distillation.This distillation column is mainly utilized to eliminate light impurities （CO,H2,CH4,etc.） from raw ethylene （＞98 wt.％）,which is determined by the follow-up vinyl acetate synthesis process.Aspen Plus was employed to do the steady-state simulation on the eolumn.After importing appropriate device parameters,the process was exported to Aspen Dynamics.The control structure was given to the process from experience and literatures at first,and then the operating conditions were studied by changing the feed flow rate,the feed flow concentration,the coolant flow rate and the heat-input flow rate.Through this simulation experiment,whether the process is able to safely,qualifiedly turn out the target product despite of disturbances to some degree and the critical operation circumstance could be acquired.Based on the simulation results,some arrangements were put forward to prevent similar incidents occurring.The dynamic simulation further supplements the steady-state simulation and might be used for reference to the actual operation.