Upgrading of an Asphaltenic Coal Residue:  Thermal Hydroprocessing

Abstract

A residue from deasphalting a syncrude obtained by direct coal liquefaction of a subbituminous Spanish coal was processed by thermal hydrotreatment. Kinetic study of the cracking reaction and coke formation reaction has been performed. The viscosity, coke content, boiling point distribution, elemental analysis, and aromaticity of the reaction products have been determined. The experimental data fits with the first-order kinetic model proposed. The main effects observed with the thermal hydrotreatment have been a large decrease of the viscosity that varies from 4608 cSt in the feedstock to 147 cSt in the products. The conversion of the heavy fraction (bp > 350 °C and soluble in toluene) and asphaltenes increased with the temperature and residence time, and the formation of coke was inhibited even at the hardest reaction conditions used. At 425 °C a kinetic control conducts the reaction, the cracking reaction with lower activation energy was more favorable and the coke formation (condensation) remained almost completely inhibited.

Resources recovery of oil sludge by pyrolysis: kinetics study

“…Hahn 24 used heavy oil dehydration facilities to treat crude oil tank bottoms and other petroleum oily sludge for the recovery of residual hydrocarbons and volume reduction. Benito et al 25 upgraded an asphaltenic coal residue, which was obtained by direct coal liquefaction of a sub-bituminous Spanish coal, by thermal hydrotreatment. It was observed that the thermal cracking took place by two competitive ®rst-order reactions with activation energies of 97 and 145 kJ mol À1 for the experimental temperatures, and yielded light distillates.…”

An overview of conversion of residues from coal liquefaction processes

“…[24] Catalytic processes include residue fluid catalytic cracking (RFCC) and hydroprocessing (hydro-treating and hydrocracking). Thermal processes include Flexicoking, Visbreaking, Gasification and Dynacracking, which have considerable advantages over the traditionally applied carbon-rejection processes such as solvent deasphalting and delayed coking.…”

“…[24] These processes produce lighter products and/or suitable feedstocks for fluid catalytic cracking and other thermal processes. Conversions have been improved with advancements in catalyst development.…”

“…Thermal processes include Flexicoking, Visbreaking, Gasification and Dynacracking, which have considerable advantages over the traditionally applied carbon-rejection processes such as solvent deasphalting and delayed coking. [24] Catalytic processes include residue fluid catalytic cracking (RFCC) and hydroprocessing (hydro-treating and hydrocracking). The process selection depends, however, on the properties of feed and the end-use of products produced.…”

“…Examples of these technologies include Shell-HDM/HCON and Veba-Combi-Cracking. [24] These processes produce lighter products and/or suitable feedstocks for fluid catalytic cracking and other thermal processes. Hydrocracking process involves a catalytic operation under rela-tively high hydrogen pressure to upgrade heavy oil fraction into lighter products of lower molecular weight.…”