96/03710 Viscosity of coal-derived liquids. 1. Application of the model to coal liquid fractions

Abstract

An investigation of the reaction chemistry of catalysed coal dissolution in recycle solvent in an inert atmosphere was carried out using low-rank British bituminous coals (Point of Ayr clean and Asfordby) and a high-rank coal (Cwm) in a tubing-bomb microreactor (25 cm3 capacity) at different temperatures (300–450°C) and reaction times (15–60 min). The results revealed that the initial rupture of the coal structure is primarily a thermolytic process, largely dependent on the severity of the reaction conditions. The threshold temperature for the dissolution of Point of Ayr (PoA) coal was ∼375°C. The catalyst, Mo-based Akzo-153, did not influence the overall conversion of coal as assessed by quinoline and THF extracts. Above 400°C, however, the catalyst promoted the hydrogenation of coal radicals generated by thermal treatment to yield more low-molecular-weight products, such as oils. The high-rank Cwm coal produced only 37 wt% (daf) of THF extracts, while the PoA and Asfordby coals yielded ∼65 wt%.