关键词:

气流床煤气化炉, 颗粒沉积, 壁面反应, 渣层

Abstract:

A model for the deposition and wall reaction of molten coal ash slag particle in entrained-flow coal gasifier was proposed.The models of flow, heat and mass transfer, and phase change of slag layer in entrained flow coal gasifier were improved.The method of numerical simulation was developed.Simulations were carried out on a Chinese pilot-scale two-stage dry feed entrained-flow gasifier.The carbon content of slag layer, wall reaction rate, thicknesses of solid slag layer and liquid slag layer, average temperature of slag layer, and average velocity of liquid slag layer were obtained with the proposed model.With increasing oxygen to coal ratio, the thicknesses of solid slag layer and liquid slag layer and carbon content of slag layer at the outlet of gasifier decreased, 〖HJ*4/9〗while the average temperature of slag layer increased.The carbon content of slag was about 14%, and carbon conversion of the gasifier was 95.2%, which agreed with the experiment data.It was revealed that wall reaction had significant effects on carbon conversion, carbon content of slag, flow and temperature of slag layer in the gasifier.It might affect the reliability of practical operation of the gasifier.

Key words:

气流床煤气化炉, 颗粒沉积, 壁面反应, 渣层