基于热量平衡的裂解炉支路温度及负荷控制方法

CONTROL METHOD OF TEMPERATURE AND LOAD OF PYROLYSIS FURNACE BRANCH BASED ON HEAT BALANCE

针对乙烯装置裂解炉在开工、正常运行和负荷调整过程中各组炉管的出口温度存在不均衡的问题,以乙烷制乙烯裂解炉为研究对象,提出基于热量平衡的裂解炉支路温度及负荷控制方法。基于裂解炉多支路炉管的结构特性,需保持支路流量调整前后的热量平衡,以消除裂解炉支路温度偏差,稳定裂解炉出口温度(COT)。同时,加入负荷控制,协同调配各支路流量分配,消除负荷变化对温度的影响。以此为基础,在集散控制系统(DCS)上设计并开发了支路温度及负荷控制器,并应用于某石化公司0.60 Mt a乙烷制乙烯装置的5台裂解炉,结果表明,该控制器可以不受负荷调整的影响,将COT波动范围精准控制在±0.5℃,支路温差波动范围控制在1℃内,减少了开工物料损失,保证了裂解炉的平稳运行。

Aiming at the problem of unbalanced outlet temperature of each group of furnace tubes during the start-up,normal operation and load adjustment of ethylene plant cracking furnace,taking the cracking furnace of ethane to ethylene as the research object,the control method of branch temperature and load of the pyrolysis furnace based on heat balance was put forward.In view of the structural characteristics of multi-branch furnace tubes,it was necessary to keep the heat balance before and after the branch flow adjustment to eliminate the temperature deviation of the cracking furnace branch and stabilize the pyrolysis furnace outlet temperature(COT).At the same time,load control was added to coordinate the flow distribution of each branch to eliminate the influence of load changes on temperature.On this basis,the branch temperature and load controller was designed and developed on the distributed control system(DCS)and applied to five cracking furnaces of 0.60 Mt a ethane to ethylene plant of a petrochemical company.The results showed that the controller could accurately control the COT within±0.5℃,and the fluctuation range of branch temperature difference was within 1℃without the influence of load adjustment,which reduced the loss of starting materials and ensured the smooth operation of the cracking furnace.