Pyrolysis of the bituminous and brown coals was studied in the circulating fluidised bed-reactor, Influence of air coal ratio on the product yields and composition was investigated. The pyrolysis was performed at temperature of 800-900 degreesC, which results from partial gasification of circulated coal char, The process was investigated in a scale of 300 kg/h of coal throughput. Particularly, the effect of dolomite addition on polyaromatic organic compounds. sulphur and chlorine distribution was investigated and discussed. (C) 2002 Elsevier Science B.V All rights reserved.