On the feasibility of constrained linear control problems with application to the ALSTOM gasifier

Abstract

In 1997 the ALSTOM Power Technology Centre issued an open challenge to the academic control community, which addressed the control of a gasifier plant at three different production levels. Despite the numerous attempts and control methodologies that have been applied to the ALSTOM benchmark case study no satisfactory solution has yet been presented. This work aims to study the feasibility of the gasifier control problem. It is shown that the problem formulation corresponds to an infeasible problem. More specifically, operation at nominal conditions (100 per cent load) is shown to be easy and minimum control effort is required to satisfy process specifications. Operation, on the other hand, at the 0 per cent load conditions is infeasible and as a result no control law can be found that satisfies all process constraints. In the light of the findings of this study it is recommended that the ALSTOM benchmark gasifier problem should be modified to alleviate the infeasibility problem.