Abstract:
A system and method for collecting hot coal tar gases emanating from a coal containing pyrolytic kiln are described. The hot coal tar gases, comprising a variety of different hydrocarbons as well as inorganic gases arising from the kiln thermal processing are transferred by diffusion and forced convection to a thermal duct in which the temperature is controlled to be maintained at a temperature below that of the kiln. The gaseous hydrocarbon with the highest condensation temperature is the first to liquefy. Additional useful hydrocarbons liquefy as the temperature of the gas continues to cool from the kiln temperature of 5000 C to one approaching the minimum duct temperature, 175 C. After a number of desirable hydrocarbons present in the coal tar gas have liquefied, the liquid contents are collected, either separately or as a combination of liquid hydrocarbons. The several remaining inorganic and some hydrocarbons gases with condensation temperatures below the minimum duct temperature are separately collected in gaseous form for further processing and/or safe disposal.