WASTE OILS USED AS SOLVENTS FOR DIFFERENT RANKS OF COAL

The effect of using different waste oils as solvent media for the liqu efaction of lignite, subbituminous, and bituminous coals was investiga ted using tubing reactors. The waste oils utilized were waste automobi le crankcase oil, oil produced by vacuum pyrolysis of waste rubber tir es, and oil produced from vacuum pyrolysis of waste plastics. Reaction s of coal and waste oils were carried out at 430 degrees C under a hyd rogen atmosphere for 1 h. Analysis of the waste automobile crankcase o il indicated the presence of heavy metals. Analyses of the oils derive d from coprocessing coals of different rank with the automotive crankc ase oil indicated that these oils were lower in overall trace metals c ompared with the trace metal content of untreated automobile crankcase oil. No coal rank dependence was observed for the removal of trace he avy metals (demetallation). Conversion yields indicated that all three solvents were similar for total gas + oil yields, asphaltene yields, and total conversion yields except for the vacuum pyrolyzed tire oil c oprocessed with Illinois No. 6 coal. Coprocessing the vacuum pyrolyzed tire oil with Illinois No. 6 coal gave the best overall conversion. T his was attributed to the presence of polyaromatic non-donor molecules present in the vacuum pyrolyzed tire oil and to the high pyrite conte nt of the Illinois No. 6 coal.