催化裂化装置裕量评价与瓶颈分析

考虑实际过程中存在着各种不确定因素,在化工过程设计时有必要对设计变量留出足够的裕量,使操作点位于过程约束边界内。基于过程稳态最优设计的一阶灵敏度分析,设计变量的局部裕量造成过程有效约束存在边界距离,操作变量进行操作优化所能获得的最大潜在经济效益是由有效约束的边界距离决定的。因此,采用操作优化得到的装置潜在经济效益可以用于对装置总体裕量进行评价。以催化裂化装置为主要研究对象,采用操作优化的方法计算装置的潜在经济效益,以此对装置的总体裕量进行评价。考虑过程的动态变化过程,结合动态优化的方法,利用稳态优化的经济效益和动态优化的经济效益对装置的总体裕量进行划分,分清保证操作控制可实现性的控制裕量和可以提升装置潜在经济效益的工艺裕量。通过分析各设计变量的局部裕量对装置总体裕量的影响确定设计瓶颈的所在,找到消除设计瓶颈的途径。

Margin evaluation and bottleneck analysis for FCCU

Because of various uncertainties in a real chemical process, it is necessary to add enough margins on design variables to let the operating point be within the boundaries of process constraints during process design.According to first-order sensitivity analysis of process steady-state optimal design, local margins added on design variables result in that there are boundary distances on process constraints, and the maximum potential economic benefits which can be obtained from operation optimization of manipulated variables are determined by the boundary distances of active constraints.Therefore, the potential economic benefits derived from operation optimization can be used to evaluate the whole margin of the device.The potential economic benefits through operation optimization were used to evaluate the whole margin of FCCU, and a dynamic optimization approach for whole margin division was presented.The whole margin was divided into control margin for ensuring controllability and process margin for realizing economic benefits of the device.Through the analysis of the relationship between local margins of design variables and the whole margin of the device, the bottlenecks of process design could be found.