Application of an optimal control scheme to a small gas-processing plant

The development of an AI product COGSYS designed to support reasoning within real-time constraints is being supported by 35 major manufacturing companies. British Gas have chosen a methanator feed gas production plant (MFGPP) for a demonstration of COGSYS. It is intended that COGSYS will address a number of key areas of process plant control including the intelligent control of highly coupled control loops arising from a chemical and physical process. The MFGPP converts a methanol and water feed into a gas of composition similar to the output from a coal gasifier. The feedstock is pressurised and vaporised and fed to 2 parallel reactors from which the gaseous product is obtained. The heat required for the endothermic reaction in one reactor and 2 vaporisers is supplied from hot circulating nitrogen. The nitrogen is heated to the operating temperature by a gas-fired heater. Cool nitrogen returning from the process units is recirculated to the heater. The paper describes the design of an optimal control scheme for the nitrogen heating loop