Modeling And Optimization Of Coal-Water Slurry Gasification Process

Coal gasification is a chemical reaction process that changing the combustible portion of coal into gas with gasifying agent in the condition of high temperature. Coal gasification technology has greatly enhanced the efficient and clean use of coal. Also, it reduced the pollution caused by coal combustion. Aspen Plus was used as developmental platform; a balance model of coal-water slurry gasification process was established in the background of Texaco coal-water slurry gasification and coal-water slurry gasification with opposed multi-burners.Based on operating characteristics and device features of Texaco coal-water slurry gasification process, a gasifier model was built by the principle of Gibbs free energy minimization. Then the gasification process model was established. The model was verified by the industrial data, and it had high accuracy. The results of sensitivity analysis show that the effective gas fraction would increase with rising concentration of coal-water slurry. Although raising oxygen-coal ratio would accelerate gasification rate, it would reduce the yield of effective gas. So oxygen-coal ratio should maintain at a certain range. High carbon conversion is good for coal's utilization but would make gasification temperature lower. Inlet water and outlet water of system were analyzed based on the balance model. Requirement of system water was optimized by changing the condensate flow rate. Optimization results can be used to indicate the water saving of industrial production.The scrubbing process model of coal-water slurry gasification with opposed multi-burners was established using Aspen Plus. The model was verified by the industrial data, and it had high accuracy. The results of sensitivity analysis show that the water/vapor ratio of outlet syngas would increase with rising condensate temperature or inlet raw gas temperature and flow rate. Increasing the pressure of water scrubbing tower and inlet raw gas or flow rate of condensate would cause a reduction in the water/vapor ratio of outlet syngas. According to the results of sensitivity analysis, the operating parameters of coal-water slurry gasification plant were optimized. The water/vapor ratio was increased, which is more helpful for the subsequent section in the production.