Research On Small Molecules In Oil Shales By Solvent Extraction

In Jilin Huadian oil shale research object, though dichloromethane, petroleumlevel two extraction, taking pictures of untreated oil shale and two level extractionresidue by SEM, analyzed dichloromethane and petroleum ether raffinate by GC/MS,research Huadian oil shale in the dissolution behaviors of the two solution as well asall levels of physical morphology of the surface of the raffinate. The results show thatwith the deepening of extraction, oil shale particles relatively smooth lamellarstructure gradually disappeared, particle size tends to be small, surface gullygradually increased, the post-stage liquid-solid raffinate have more contact area.Dichloromethane and petroleum ether have ability to dissolute the paraffin in the oilshale. The major components of extract are the C15to C28saturated alkane. Solventextraction method can effectively extract in a class or group of similar compoundsfrom oil shale. The study of oil shale extraction has an important significance to theconstitution of oil shale and extracts the constituent of high economic value.The oil shales from Maoming, Guangdong province and Fushun, Liaoningprovince were selected for hydrochloric acid pickling. Dichloromethane andtetrahydrofuran were used to extract oil shales before and after acid pickling. Theextracts of dichloromethane and tetrahydrofuran extractions were characterized andthe leaching behavior of small molecules was concluded using GC/MS analysis. Theresults show that the treatment processes of hydrochloric acid pickling can improvethe extraction yield. The compositions of alkanes in extracts are less influenced by thehydrochloric acid pickling than the oxygenated small molecules. The relative contentof extracts or the quantity of detectable compounds changes somewhat by comparingthe extracts of the same sample before and after acid pickling. The majority extractsof dichloromethane are alkanes. The majority extracts of tetrahydrofuran areoxygenated small molecules compounds.Oil shales were selected for hydrochloric acid pickling. Dichloromethane and tetrahydrofuran were used to extract oil shales before and after acid pickling.Compositions of extracts were analyzed by GC/MS. The adsorption capacity and porestructure changes in extraction residues were tested by pore structure analyzer.Occurrence manner of small soluble molecules was concluded by the dissolution ofsmall molecules and the change of pore structures. The results showed that themajority extracts of dichloromethane are alkanes. The majority extracts oftetrahydrofuran are oxygenated small molecules compounds. Hydrochloric acidpickling will make more pores which conducive to the dissolution of small molecules.The number of medium and large pores in oil shale will increase after solventextraction. The small soluble molecules can hide in the pore structure of oil shale andthe small soluble molecules which gathered on the surface of oil shale can make newpore or expand the pore size while in the process of dissolution.