Experimental study of a commercial circulated fluidized bed coal gasifier

This paper presented the performance data of a commercial scale circulating fluidized bed gasifier, CFBG-800-I. The operation condition effects on gasifier temperature distribution and gasifier performance were studied. It is found that the external cycle has a critical influence on the gasifier temperature profiles. Both the Air/Coal ratio and Steam/Coal ratio affect the bed temperature. The increasing in Air/Coal ratio decreases the valuable gases content, which is adverse to the gasifier performance but increases the gasifier temperature, which is favorable for the gasification reactions. The best choice of the Air/Coal ratio is a tradeoff of gasifier performance and gasifier temperature. The Steam/Coal ratio could influence gasifier temperature and gasifier performance in several ways. Increasing steam increased the water gas reaction and the CO, H2 concentrations increase firstly, and then decrease at a Steam/Coal ratio of 0.32. Increased Steam/Coal ratio decreases the bed temperature, which is bad for the gasifier performance, and will decrease the carbon conversion efficiency. The Steam/Coal ratio should be carefully selected by comprehensive evaluation also.