Soft Sensor for Inputs and Parameters Using Nonlinear Singular State Observer in Chemical Processes

Chemical processes are usually nonlinear singular systems. In this study, a soft sensor using nonlinear singular state observer is established for unknown inputs and uncertain model parameters in chemi...     

化工过程基于广义非线性状态观测器的不可测输入和不确定模型参数软仪表(英文)

Chemical processes are usually nonlinear singular systems. In this study, a soft sensor using nonlinear singular state observer is established for unknown inputs and uncertain model parameters in chemical processes, which are augmented as state variables. Based on the observability of the singular system, this paper presents a simplified observability criterion under certain conditions for unknown inputs and uncertain model parameters. When the observability is satisfied, the unknown inputs and the uncertain model parameters are estimated online by the soft sensor using augmented nonlinear singular state observer. The riser reactor of fluid catalytic cracking unit is used as an example for analysis and simulation. With the catalyst circulation rate as the only unknown input without model error, one temperature sensor at the riser reactor outlet will ensure the correct estimation for the catalyst cir- culation rate. However, when uncertain model parameters also exist, additional temperature sensors must be used to ensure correct estimation for unknown inputs and uncertain model parameters of chemical processes.     

基于广义状态观测器的催化裂化装置软仪表

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。