Experimental study on the coal tar hydrocracking process in supercritical solvents

A review of upgrading heavy oils with supercritical fluids

“…17 The yield of light oil from the cracking of high temperature coal tar and low temperature coal tar were both improved. 6 They found that hydrocarbons with weak bonds, such as tert-butyl benzene, heptylbenzene and heptyl-naphthalene can be cracked in SCW easily. Additionally, C-O, C-S and C-N bonds can be easily cleaved to generate small molecule compounds.…”

“…A similar phenomenon showed that light oil yield increases gradually with increasing temperature in supercritical gasoline until the temperature is increased up to 653 K. Then the light oil yield starts to decrease. 6 The density of SCW is another signicant parameter that can control the upgrading result. The solubility of heavy oils increases with the density of SCW.…”

“…57,62 In detail, the oxides of Ce, Co, Fe, Mo, and Zn catalysts have been commonly used in SCW. 6,63 In the catalytic cracking process, Ni-Mo loaded on a Y zeolite support is effective for the reaction, and the noble metals Pt and Pd have a high activity for the hydrogenation of aromatics. [64][65][66][67][68][69][70] Gu et al selected xylene and gasoline as the solvents to modify high and low temperature coal tar using NaY zeolite (Na 56 [(AlO 2 ) 56 (SiO 2 ) 136 ]$ 264 H 2 O) as the catalyst.…”

“…Additionally, the present upgrading processes in industry mainly aim at the cracking of a certain range of boiling points of heavy oils and the processes have to be carried out in a set of complex and expensive multi-stage reactors. [6][7][8] Therefore, several new technologies should be developed to convert the heavy and extraheavy oils into light products efficiently and environmentally.…”

Effect of Mass Ratio of Solvent to Solute and Pressure in Supercritical Fluid Extraction of Coal Tar

“…Therefore, for many solids or solutes in fluids, if their miscibilities are limited in certain solvents, the solving abilities of supercritical fluids present obvious correlations with pressure. Besides, different solutes would be affected distinctively [6]. Meanwhile, pressure is restricted by equipment, security and production costs, so the extraction yield should be improved on the bases of production resources and entire operational parameters.…”