STUDY ON COAL COMBUSTION AND PYROLYSIS GAS TAR AND STEAM POLYGENERATION SYSTEM

摘要

A new polygeneration system combined coal combustion and pyrolysis has been developed for clean and high efficient utilization of coal. Coal is first pyrolysed in gasifier and produced gas is then purified and used for industrial purpose or as gas turbine fuel; tar is collected during purification and can be processed to extract monocyclic aromatic hydrocarbons (MAHs) and polycyclic aromatic hydrocarbons (PAHs) etc., or to make liquid fuels by hydrorefining; semi-coke from the gasifier is burned in a circulating fluidized bed (CFB) boiler for heat or power generation. A 1MW pilot plant test facility has been constructed. The primary results show that it can produce 12-14MJ/Nm3 middle heating value gas and 5-8 wt. % tar when bed temperature is 500-600 °C. On basis of this, a 12 MW system, a 75t/h CFB boiler combined with a fluidized bed gasifier, has been designed for realizing gas, tar and steam polygeneration, which can produce 1910 Nm3/h gas with higher heating value (HHV) 24-26 MJ/Nm3, 1.17 t/h tar and 12 MW power.