Research on Coal Pyrolysis and Combustion Poly-generation System

A new poly-generation system combined coal combustion and pyrolysis has been developed for clean and high efficient utilization of coal. Coal is first pyrolyzed in a fluidized bed gasifier and produced gas is then purified and used for MeOH or DME production. Tar is collected during purification and can be processed to extract monocyclic aromatic hydrocarbons, polycyclic aromatic hydrocarbons and to make liquid fuels by hydrorefining. Semi-coke from the gasifier is burned in a CFB boiler for heat or power generation. A 12MW CFB gas, tar, heat and power poly-generation system was erected by Zhejiang University in cooperation with the Huainan Mining Industry (Group) Co., Ltd. in 2007. The experimental study focused on the two fluidized bed operation and characterization of gas, tar and char yields and compositions. The results showed that the system could operate stable, and produce about 0.12Nm³/kg gas with 22MJ/Nm³ heating value and about 10wt.% tar when pyrolysis temperature between 500 and 600°C. The produced gases were mainly H₂, CH₄, N₂, CO, CO₂, C₂H₄, C₂H₆, C₃H₆ and C₃H₈. Gas component concentrations were 24.18, 36.29, 7.96, 5.6, 7.84, 11.70 and 3.28%, respectively. The CFB boiler run steadily, whether the gasifier run or not, and produced 12MW power.