Partial and complete oxidation of brown coal in a supercritical water–oxygen fluid under conditions of counterflowing reactant streams

Abstract

The oxidation of brown coal continuously fed as part of a coal–water slurry into a counterflowing stream of a supercritical water–oxygen fluid at a temperature difference along the reactor axis of 673–873 K and a pressure of 30 MPa has been studied. It has been found that, in the case of a partial combustion of coal (under conditions of O₂ deficiency), the yield of hydrogen-enriched products increases owing to heat evolution. Under conditions of excess O₂, coal undergoes complete oxidation. In this case, the heat evolved per unit volume of furnace space is about 1.0 MW/m³. It has been shown that the heat consumed for the implementation of the process using external sources can be partially or completely compensated for by heat evolution during homogeneous and heterogeneous combustion coupled with coal thermolysis.