气体分馏装置先进控制技术应用

大连石化公司第三套气体分馏装置设计加工能力为50×10^4t/a,生产的粗丙烯纯度为99.5%,原采用美国霍尼韦尔公司的集散控制系统（DCS）,控制方案以单回路和串级回路PID控制为主。为了进一步提高丙烯收率和产品分离精度,实施了先进控制系统应用项目,对影响收率和产品质量的塔进料量、进料温度、塔底温度、塔顶温度、压力、回流量、回流温度、塔液位等参数进行优化控制,特别是对最主要的影响因素塔顶温度和塔底温度进行优化控制。介绍了先进控制系统的控制目标、设计依据、控制方案和应用情况。经过一年的工程开发和现场调试,装置的先进控制系统投用率达到90%以上,丙烯收率提高0.55%,装置综合能耗降低2.36kg标油/t,每年增产丙烯825t,装置每年可创造经济效益730.8万元,同时装置的操作平稳率大幅提高。

Application of Advanced Process Control Technology in Gas Fractionation Unit

PetroChina Dalian Petrochemical Company ＇s third gas fraction ation unit has a design processing capacity of 50×10^4t/a and the purity of crude propylene produced by the unit is 99.5%.The unit originally used Honeywell＇s distributed control system（DCS） and single-circuit and cascade PID control design.To raise the yield of propylene and the accuracy of product separation,the company introduced an Advanced Process Control system to optimize the parameters that will affect the yield and quality of products such as the tower＇s charging rate ,feed temperature ,bottom temperature ,top temperature,pressure ,quantity of reflux,reflux temperature and liquid level.Particularly,the introduction of the system can lead to the optimization of the key influencing factors-the temperatures at the top and bottom of the tower.This article describes the control objectives,basis for design,control schemes and applications.After one year of engineering development and on- site commissioning,over 90% of the components of the third gas fractionation unit were controlled by the Advanced Process Control system.As a result,the unit＇s propylene yield increased by 0.55% ,overall energy consumption for processing one ton of feedstock dropped by 2.36kg of oil equivalent and annual output increased by 825 tons.The unit＇s operating stability has also improved significantly.The average annual revenue generated by the unit has reached 7.308 million Yuan.