The ALSTOM benchmark challenge on gasifier control

Integrated gasification combined cycle power plants are being developed around the world to provide environmentally clean and efficient power generation from coal. As part of the UK's Clean Coal Power Generation Group, ALSTOM (formerly GEC ALSTHOM) has undertaken a detailed feasibility study on the development of a small-scale prototype integrated plant (PIP), based on the air-blown gasification cycle. In pursuit of this goal the ALSTOM Power Technology Centre (formerly the GEC ALSTHOM Mechanical Engineering Centre) has produced a comprehensive dynamic model and control philosophy for the PIP. The gasifier is one component of the model which, being a highly coupled multi-variable system with five inputs (coal, limestone, air, steam and char extraction) and four outputs (pressure, temperature, bed mass and gas quality), has been found to be particularly difficult to control. For this reason the gasifier, together with its associated control specification, operating constraints and various disturbance characteristics, has been selected as the subject for this control challenge. This paper provides a brief background to the problem and describes the control specification and closed-loop tests to be performed.