A kinetic analysis of coal liquefaction in flow reactors of the 1 t/d Process Supporting Unit (PSU) for the NEDOL Process is reported. The coal liquefaction section of the PSU consists of a preheater and three liquefaction reactors in series. Progress of coal liquefaction in PSU has been investigated, focussing mainly on the changes in coal derived insoluble components through the preheater and the reactors. Summing up those results, a reaction kinetic model of coal liquefaction with retrogressive reaction was established and a mechanism of coal liquefaction in the process was elucidated. (C) 2000 Elsevier Science Ltd. All rights reserved.