EFFECT OF CRUDE-OIL TYPE AND HEATING RATE ON COMBUSTION OF CRUDE-OIL LIGNITE MIXTURES

Research was conducted to investigate the possibility of upgrading low-quality lignites by mixing them with heavy crude oils. Three crude oil samples with API gravities of 12.9, 18.7 and 26.7 were mixed with lignite to form mixtures of 10 and 20% oil content. Thermal analysis experiments were conducted at non-isothermal heating conditions at heating rates of 5-100 K min-1. Differential thermogravimetric data were analysed using an Arrhenius-type reaction model assuming a first-order reaction. The results indicate that the combustion of mixtures as observed on thermograms is very similar to that of lignite. However, the activation energy and reaction peak temperatures increased as the oil content in the mixture increased.