Abstract: Other than the conventional soft sensor of output correction, the primary variables of soft sensor in FCCU riser reactor are completely unmeasurable in real time, and they can only be corrected on-line by secondary variables, so the state observer was used to build soft sensor.FCCU is an index-one nonlinear singular system, so an index-one nonlinear singular state observer was designed for soft sensor to estimate the unmeasurable variables on-line, including product yields and catalyst circulation rate of FCCU.For index-one nonlinear singular system, if the linear parameter-varying singular system from local linearization at current operating point was detectable, a nonlinear singular state observer could run in a wide range, and its feedback gain matrix can be obtained on-line by pole assignment of the linearized system.The existence of nonlinear singular state observer can ensure that the estimated values of the primary variables will converge to their ideal values.Simulation showed that even if the catalyst circulation rate was unknown, when it was augmented as state variable and the temperature of FCCU riser outlet as secondary variable was used for output correction, a soft sensor based on nonlinear singular state observer could be established to estimate the unmeasurable variables, such as product yields and catalyst circulation rate on-line.The estimated values of the unmeasurable variables converged to the ideal values and the proposed observer had good dynamic performance.

Key words: soft sensor, state observer, nonlinear singular system, FCCU

摘要： 与常规的输出校正软仪表不同,催化裂化装置软仪表的主导变量完全不可测,只能通过辅助变量进行在线校正,因此利用状态观测器构造催化裂化装置软仪表。催化裂化装置为指数1型广义非线性系统,理论分析证明,如果指数1型广义非线性系统在工作点线性化得到的广义线性变参数系统能检测,则可以通过线性化系统的在线极点配置来选取合适的状态观测器反馈增益阵,以确保广义状态观测器存在并在较大范围内是稳定的,从而保证软仪表对主导变量的在线估计值可以收敛于理论值。仿真结果表明,即使催化剂循环量为不可测输入变量,将其扩展为状态变量后,利用提升管反应器出口温度作为辅助变量进行在线校正,即可构成催化裂化装置软仪表完成对油品产率、催化剂循环量等不可测变量的在线估计,估计值能够稳定收敛到理论值并具有较好的动态性能。

关键词: 软仪表, 状态观测器, 广义非线性系统, 催化裂化装置