Effects of mechanical activation on the co-liquefaction of Xigou sub-bituminous coal from Xinjiang and Karamay petroleum vacuum residues

- Effects of mechanical activation (MA) on coal were investigated.
- MA changes the physico-chemical properties of coal sample.
- MA decreases the apparent activation energy of coal at the range from 300 to 400 °C.
- MA increases total oil yield but decreases residue yield.

The effects of mechanical activation on the co-liquefaction of Xigou sub-bituminous coal (XSBC) and a mixture solvent of creosote oil and Karamay petroleum vacuum residues were investigated. The structure of the mechanically activated coal was more porous than the structure of XSBC according to the characterization results. Compared to XSBC, the average pore size of the activated coal increased by 106.7%, whereas the specific surface area decreased by 74.7%. The absorption peaks of OH at 3300 cm− 1 and CO at 1720-1650 cm− 1 decreased. The ratio of the fractions of aromatic carbon and sp2-hybridized carbon decreased by 13%. The mass loss from 100 °C to 300 °C increased by 237% and the apparent activation energy in the liquefaction temperature range of 300-400 °C decreased by 21.6%. The yields of total oil, asphaltene and preasphaltene (A + PA), gas and residue of mechanical activated coal slurry were 82.67, 10.80, 4.12 and 2.40%, respectively. Compared to raw coal slurry, the total oil yield and the gas yield of activated coal slurry increased by 8.2 and 63.5%, respectively, whereas the A + PA yield and the residue yield decreased by 29.9 and 57.5%, respectively. The H2 consumption decreased by 19.9%. Moreover, the yield of heavy oil and distillate in the liquefied product decreased by 51.1 and 31.3%, respectively, whereas the yields of gasoline and diesel increased by 65.5 and 10.7%, respectively.

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