Coal dust low-temp carbonization - by flue gases from boiler and cyclone separating semicoke for boiler firing

摘要

In a low-temp carbonization process for hard or brown coal, the raw material is pulverized coal with a size consist similar to that used in pulverized coal fired boilers. The coal dust is mixed with hot flue gases which turn it instantly into suspended semicoke particles. These are separated from the gases in a cyclone and passed by a carrier gas to the burner of a boiler furnace. The mixture of low-temperature gas and flue gases is passed through a cooler where the condensed products are collected for the recovery of carbon derivatives. The gas is desulphurized and fed to the same burners as the semicoke. This saves the expense of the erection of low-temperature carbonization ovens and the environmental pollution caused by them. The system can be applied to new as well as to existing steam boiler installations. The semicoke cooling plant is saved, the coal by-products are recovered and the flue gases are freed from sulphur prior to emission into the atmosphere.