International Journal of Engineering and Technology

Many researchers showed their interest in solving the two challenge problems posed on academic community on controlling the gasifier by ALSTOM. Earlier part of the researchers tried advanced controller methods using the higher order state space model provided by ALSTOM. But, the inability to meet some constraints during integrated model and controller simulation, the authors have desired lower order MIMO transfer function models for the gasifier. Accordingly three lower order model representations for original higher order gasifier came to surface. However lower order model derived based on balanced realisation using Hankel singularity values method has only been successful in controlling gasifier for different types of disturbances and simultaneously meeting the input/output constraints. In this paper the authors investigate why all lower order model representation could not become successful sans balanced realisation method.