Optimization of the Integrated Gasification Combined Cycle using Advanced Mathematical Models

Abstract Entrained flow gasifiers are known to operate under very severe conditions in order to achieve very high conversions of up to 99%. The extreme conditions impact negatively on the capital and operating investments of the gasifier and the downstream units. There is, however, no evidence on the published models that the extreme conditions are the optimal conditions in achieving the maximum fuel gas heating value. The first part of this work presents a 1-D simulation model for a dry-fed entrained flow gasifier with oxygen and steam used as oxidizing agent. The model is then validated against published models for the similar reactor configuration and then extended to an existing entrained flow gasifier for an IGCC power plant in Puertollano, Spain. The second part then presents the optimization model in which the objective function is to maximize the heating value of the fuel gas. The results obtained during optimization of the gasifier indicate a 12% increase in heating value with a decrease of about 500 K in operating temperature. A 3 MPa increase in operating pressure only results in less than 2% increase in fuel gas heating value. Milder operating conditions signify the possibility of a decreasing operating and capital investments, thereby improving the operating cycle of the power plant.

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