Design of Digital Controller for An Unstable CSTR Process

Abstract

Continuous Stirred Tank Reactor (CSTR) plays a vital role in almost all the chemical industrial processes. CSTR is a highly nonlinear process exhibiting stable and unstable steady state at different regions. Control of the temperature of the CSTR process in the entire operating range is a difficult task. This paper deals with the design of a digital pole placement controller for a jacketed chemical reactor system which is an open loop unstable system due to the effect of scale-up on the steady state and dynamic characteristics. The proposed pole placement digital controller is capable of providing system stability and also provides set point tracking and disturbance rejection. A 1 DOF and 2 DOF digital pole placement controller is designed using the transfer function approach for the specified constraints namely peak overshoot and rise time. The simulation result shows the feasibility of using the proposed controller for control of the unstable CSTR process.

Keywords: 1 DOF, 2 DOF controller, pole placement, unstable CSTR