Retrogressive reactions in coal/petroleum coprocessing

he objective of this study was to examine the processes in coal/petroleum coprocessing systems which lead to coke formation and specifically, the interactions between the petroleum residua and coal, leading to retrogressive reaction products. Five coals were reacted with five model compounds ranging from paraffinic to fully aromatic. Coal conversions were influenced by reaction temperature, which affects the coal and the solvent behavior. The most effective solvent for enhancing coal conversion was pyrene and the other model compounds were grouped based on the generated radicals (1) eicosane and 1-phenyldodecane exhibited similar behavior and (2) 1,4-diisopropylbenzene and 1,2,4,5-tetramethylbenzene showed similar behavior.;Coprocessing experiments were conducted using the five coals and three petroleum residua. The coal conversions at 350 and 400;The solid reaction residues were examined by optical microscopy, NMR and FTIR. The interactions between the coal and the residuum become important at temperatures above 400;Structural changes observed in the residues by...