Process for degasifying fine-grained fuels

Abstract

Fine-grained fuels such as coal are continuously degasified by a process wherein a fine-grained degasified residue is recirculated as a heat-carrying medium and is heated in a pneumatic conveyor line and then fed to a collecting vessel. A first partial stream of the heat-carrying medium is fed through a mixing zone together with the fuel to be subjected to dry distillation. A second partial stream of the heat-carrying medium is fed to a secondary degasification zone together with the mixture comprising the dry distillation residue. Volatile constituents are distilled from the mixture in the mixing zone and the secondary degasification zone and are fed to dust-collecting and condensing means. Degasified residue is recirculated to the pneumatic conveyor line. The ratio of the rate of the second partial stream fed to the secondary gasification zone to the rate of the first partial stream of the degasified residue, which first partial stream is fed to the mixing zone for the dry distillation of the fuel, is between 0.2:1 and 15:1. The second partial stream is mixed with the dry distillation residue before the second partial stream is fed to the secondary degasification zone and degasified residue dust is discharged in a particle size of more than 75% below 0.3 mm.