HYDROGEN-TRANSFER FROM TETRALIN AND DECALIN TO HIGH-TEMPERATURE COAL TARS - RELATION WITH CARBON DEPOSIT FORMATION

Studies of pyrolysis of a coal charge containing various quantities of water from 0.8 to 15 wt.% in a two-stage reactor were performed. The rate of formation of solid carbon deposits was followed and some prope rties of high-temperature tars were investigated. These tars differ in elemental composition and hexane solubility. Hydrogen acceptor abilit ies were evaluated by reaction with tetralin at 320 degrees C and with decalin at 400 degrees C. Hydrogen transfer from decalin to several m odel organic compounds was also studied. The rate of carbon deposit fo rmation and hydrogen acceptor abilities of tars are different for vari ous quantities of water in the starting coal charge. The relation betw een the hydrogen transfer properties of tars expressed as the ratio of decalin hydrogen transfer (DHT) to tetralin hydrogen transfer (THT) a nd the rate of carbon deposit formation seems to indicate the importan ce of hydrogen transfer during secondary pyrolysis.