Research on coal pyrolysis and combustion poly-generation system

Abstract

A new poly-generation system combined coal combustion and pyrolysis has been developed for clean and high efficient utilization of coal. Coal is first pyrolysed 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 12 MW 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 0.12 Nm3/kg gas with 22 MJ/Nm3 heating value and about 10 wt % tar when pyrolysis temperature between 500~600°C. The produced gases were mainly H2, CH 4, 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 12 MW power. © Tsinghua University Press, Beijing and Springer-Verlag Berlin Heidelberg 2012.