Performance of an Integrated Gasification Combined Cycle System with Different System Integration Options

The integrated gasification combined cycle system includes a gasifier, air separation unit (ASU), heat recovery steam generator (HRSG), syngas coolers, and combined cycle system. The HRSG, syngas coolers, ASU, and gas turbine can affect the system efficiency, and their integration is of importance. This work investigates the integration of the HRSG and syngas coolers and the integration of the gas turbine and the ASU. First, it is found that the best match between the HRSG and syngas coolers is for the HRSG to provide high-pressure water to the syngas coolers, which return superheated steam back to the HRSG. Second, from the viewpoint of system efficiency, it is found that a lower integration air separation coefficient (Xas) or higher nitrogen re-injection coefficient (Xgn) is acceptable for an integrated gasification combined cycle system with a low-pressure ASU. A lower Xas is recommended for Xgn = 0%, and Xas = 50% is acceptable for Xgn = 100%. For Xas = 0%, Xgn = 30% is recommended, and a higher Xgn i...