摘要
催化裂化是目前炼油厂中的核心加工工艺,其反应-再生系统是一个多变量紧密耦合的复杂系统,动态模拟和控制系统设计难度较大。目前,催化裂化装置在进行动态建模时设置了大量假设条件,与实际状况存在诸多不符,另外当前的控制回路配对方法未考虑工艺要求,也不适用于催化裂化这样的开环不稳定系统。基于以上原因,以已建立的反应-再生系统数学模型为基础,建立精细化动态模型,对反应器和再生器模型进行真实逼近,不再忽略气相动态变化,将原模型中气相对时间的导数项恢复,通过离散化的分布参数系统模型,对离散化模型中每段提升管和烧焦罐的时变变量加入时滞。仿真结果表明,精细化动态模型更加接近实际化工生产过程。根据上述模型搭建仿真平台,通过对不稳定的反再系统进行工艺优先的控制系统设计,首先根据化工工艺设计控制回路保证系统的稳定性,然后基于相对增益阵方法设计剩余变量配对,在降低了高维系统设计复杂度的同时保证了生产过程安全。设计结果表明,对于催化裂化装置反再系统,基于工艺特性完成控制回路配对后,剩余变量无须再添加多余的控制回路就能保证控制系统的稳定性和适当的控制性能。
Catalytic cracking is the core processing technology in the current refinery.Its reaction-regeneration system is a complex system closely coupled with multiple variables.It is difficult to design dynamic simulation and control systems.At present,a large number of assumptions have been set up in the process of dynamic modeling of FCCU,which is inconsistent with the actual situation.In addition,the current control loop configuration method does not consider the process requirements and is not suitable for open-loop unstable systems such as FCC.For the above reasons,based on the mathematical model of reactor-regenerator system established by the author,this paper establishes a refined dynamic model to approximate the reactor and regenerator models,no longer ignoring the dynamic changes of gas phase,recover the derivative term of gas relative time in the original model,and through the discrete distributed parameter system model,time delay is added to the time-varying variables of each riser and coke can in the discrete model.The simulation results show that the refined dynamic model is closer to the actual chemical commercial process.Based on the above models,a simulation platform is built to design the prior process analysis based control system for the unstable reactor-regenerator system.Firstly,the control loop is configurated according to the chemical process to ensure the system stability,and then design the matching of remaining variables based on relative gain array method,which not only reduces the design complexity of the highdimensional system,but also ensures the safety of the commercial process.The design results show that for FCCU reactor-regenerator system,after the control loop configuration is completed based on the process characteristics,the remaining variables can ensure the stability and appropriate control performance of the control system without adding additional control loops.
作者
张兴硕
罗雄麟
许锋
ZHANG Xingshuo;LUO Xionglin;XU Feng(Department of Automation,College of Information Science and Engineering,China University of Petroleum,Beijing 102249,China)
出处
《化工学报》
EI
CAS
CSCD
北大核心
2022年第2期747-758,共12页
CIESC Journal
基金
国家自然科学基金项目(21676295)。
