Hybrid RTO with zone control MPC applied to a Gas-lift system

Abstract

In this paper, a steady state real time optimization (SRTO) using transient measurement, implemented with a zone control model predictive control (MPC) is applied to a gas-lift system. The use of zone control MPC is suitable for processes where the exact values of the controlled output are not required, but they must be within a specified desirable zone. The control strategy allows the controller to focus on reaching the desired input target supplied by the optimization layer, as long as the outputs are kept within their specified zones and dynamic constraints are respected. With the focus on practicality of application; available, established and successfully implemented process optimization and control techniques are harnessed, through some modifications to fit the process and achieve an optimum. Simulations show that the controller can drive the process to and keep the output within their specified region and also track the desired input target, even in the presence of disturbance.