Flow and heat transfer characteristics in the syngas quench system of a 300 MWe IGCC process

In the Shell coal gasification process, the hot syngas at about 1550 C leaving the gasifier exit is immediately quenched by recycled cold syngas for protection of the system from corrosion and fly slag deposition. As the gas quench system is composed of membrane walls with evaporating water inside, understanding the heat transfer is important in the design and operation of gasification process. This study investigated the detailed flow and heat transfer characteristics of the gas quench system by computational fluid dynamics (CFD) for operational loads of 50-100% in a 300 MWe integrated coal gasification combined cycle (IGCC) process. Based on the CFD results, one-dimensional process model for heat transfer was proposed. The approach for considering three gas streams (hot, cold and mixed syngas) was effective in predicting the trends of heat transfer and gas temperature in the quench system.