COLIQUEFACTION OF COAL AND NEWSPRINT-DERIVED LIGNIN

When lignin derived from newsprint is coliquefied with Illinois coal in tetralin under mild reaction conditions (initial hydrogen pressure of 1.07 MPa), up to 90% enhancement in coal conversion is observed. The enhancement in coal conversion is a function of liquefaction temperature. It increases from 50 to 90% as the temperature is increased from 300-degrees-C to 325-degrees-C; however, with a further increase in temperature, the enhancement declines. This behavior is explained in terms of reaction chemistry that postulates that intermediates formed during lignin depolymerization react with coal via a parallel coal depolymerization pathway. The quality of liquid products was assessed by examining the boiling point fraction data. Data clearly show synergism in terms of product quality when lignin is added to coal during depolymerization.