Modelling of consumer dynamics to improve fuel gas blending control

Abstract

Although fuel gas systems represent a large part of industrial chemical processes, there has been limited literature on their modelling and control. The available literature typically neglects the effects of fuel gas consumer dynamics, leaving much of the system’s important dynamic behaviour omitted. This paper aims to contribute to the existing literature on fuel gas control and improve an existing fuel gas control benchmark problem by including the effects of fuel gas consumer dynamics on the system. Two model predictive controllers (MPC) were designed, where the first MPC uses a model that neglects the consumer dynamics and the second MPC uses a model that includes the consumer dynamics. It was found that the MPC neglecting consumer dynamics has a pressure variability 5.8 times higher than the MPC that includes the dynamics. It also has a relative sensitivity index (RSI) of 7.2, indicating the presence of model-plant mismatches (MPM) affecting controller performance.