Noncatalytic liquefaction of tar with low-temperature hydrothermal treatment

Water at hydrothermal and supercritical conditions is considered a promising solvent for the degradation of hazardous waste into harmless compounds. Tar liquefaction experiments were conducted using a batch-type reactor at temperatures between 623 K and 673 K and at pressures between 25 and 40 MPa. A reaction mechanism for tar liquefaction is proposed. Moreover, on the basis of the experimental results, this method could become an efficient method for tar liquefaction, producing high yields of valuable chemical intermediates.