MPC-PID Control of a Gas-Liquid Cylindrical Cyclone

Abstract

Offshore oil production facilities exhibit nonlinear dynamic characteristics. With the existence of many flow regulating valves, these dynamics require to be linearized in order to achieve the performance criteria necessary for production of hydrocarbons. Consequently, the dynamic nature of these valves affect their production performance as regular tuning of process controllers are required due to changes in reservoir fluid flow and future constraints. To address this phenomenon, this paper proposes an MPC-PID control system strategy for offshore oil production platform. This strategy includes the use of model predictive controller providing the most economic and efficient set point for distributed PID controllers in the respective loops. The model predictive controller employs a strategy based on the process model to solve the optimal control problem. The proposed approach is further developed using a dynamic engineering design tools available in MATLAB/Simulink and implemented on Gas- Liquid Cylindrical Cyclone (GLCC) compact separator. The system is subjected to set point variation and process disturbances. The results indicate stable controller design and prove the ability of MPC controller to handle constraints and reject disturbances while reducing the energy required and hence overall reduction in production cost with maximum performance.