Advanced integrated gasification combined cycle (A-IGCC) by exergy recuperation - technical challenges for future generations

With the limited worldwide resource of coal, a new technology has been developed in using a low grade coal to breakthrough the current technical limitation in the IGCC system and attains higher plant efficiency. This study attempts an exergy-recuperation within the combined cycle on HYSYS process simulation, so called Advanced IGCC (A-IGCC), in which the system is designed to increase the cold gas efficiency and save the exergy of the fuel throughout the system by using a gas turbine exhaust as an external heat source encouraging an autothermal reaction. Three types of syngas compositions were investigated depending on the gasifier conditions with exergy recuperation. Plant efficiency was significantly higher with the presence of exergy recuperation in the system. This was attributed to an efficient exergy saving in the system as opposed to a conventional IGCC, which has significant exergy loss in the combustion and gasification processes. Improved plant performance generated from a low temperature gasifier was obtained with the A-IGCC model, although the model requires further developments in technology, such as the gasification at a lower gas temperature, powerful heat exchanger, gas purification at high temperature, etc., for the actual implementation.