Abstract
Three kinds of coal liquefaction residues obtained from PDU were characterized and compared with the raw coals by proximate and ultimate analyses, solvent separation and thermo-balance equipped with a pyrolysis-gas analyser. Each residue contains 22-38% of ash and 0.69-0.86 atomic ratio H/C. When the residues were heated up to 1000°C in a stream of N2 gas, H2 gas was generated severely at about 400 and 800 for, residues S (raw coal: Wandoan (76%C)) and N (raw coal: Illinois No.6 (79%C)) and at 800 for residue K (raw coal: Morwell (65%C)).
The amount of the H2 gas was 70-80% of total gas evolved. Tar contents estimated from the weight of generated gas (3-12%) and pyrolysis residue (char and ash, 17-51%) were 17, 23 and 51% for S, K and N samples, respectively. It is assumed that the difference of tar yields is due to the difference of the severity in liquefactions and of separation methods of residues rather than those of the raw coals used in the processes.
