Publikace (přehled)

Direct coal liquefaction (DCL) is a suitable way of producing synthetic fuels from low-rank coals, especially when the waste-derived materials are co-processed during the process. However, direct liquid product yield is affected by many factors such as temperature, pressure, reaction time, heating rate, type of the solvent and/or even the coal itself. In this research, we attempted to maximize the liquid yields by optimizing the reaction conditions using coal impregnated by 1% weight of molybdenum. Waste tire pyrolysis oil was used as a feedstock. For this purpose, DCL reactions were carried out in an autoclave. The solvent to coal ratio was 2:5 and the initial hydrogen pressure was 34.4 bar. To improve the process efficiency, three reaction times (30, 60, 120 min.), two heating rates (5.6, 8.3 °C/min) and two reaction temperatures (400, 420 °C), were tested. The best liquid yield was found for the test with the shortest reaction time, lower temperature and slower heating rate. For the reactions with a temperature of 420 °C, higher heating rate and different reaction times, a significant increment in gas formation and a slight decrease in the formation of solids was found. Surprisingly, for the same reaction temperature and slower heating rate, the opposite trend was observed. Thus, the most significant parameters affecting direct liquid yield for the investigated set of materials seemed to be the heating rate, reaction time and temperature respectively.