Study On Occurrence Relationship Between Organic Matter And Inorganic Mineral And The Structural Characteristics Of Organic Matter In Oil Shale

With the huge consumption and the increased cost of petroleum exploitation,alternative energy sources have gradually attracted people's attention.Oil shale,as a kind of important auxiliary energy,has been widely concerned by the researchers in the world.Previous studies showed that oil shale is a sedimentary rock with the solid organic matter distributed in inorganic mineral skeleton.As a kind of fossil fuels similar to coal,oil shale has high mineral contents.Its inorganic minerals affect the gaseous products and increase the pyrolysis residues during pyrolysis,while the intrinsic molecular structures of its organic matter can be used to guide the pyrolysis conditions.Hence,it is essential to study the occurrence relationship between organic matter and inorganic mineral and the structural characteristics of organic matter in oil shale for the efficient utilization of oil shale.In this paper,stepwise treatment was used to study the occurrence relationship between organic matter and inorganic mineral;in order to reveal the structural characteristics of organic matter in oil shale at the molecular level,two degradation methods,thermal dissolution and catalytic hydrogenation were used to dissociate the organic matter in oil shale,combined with a variety of characterization techniques to reflect the structural change in the degradation process.The main work and conclusions of this paper are shown as follows:(1)The content of organic carbon and inorganic mineral structural form in three kinds of oil shale were studied by extraction,alkaline hydrolysis,acid hydrolysis,and HF treatment,separately,and then the structural changes of oil shale before and after treatment were comparatively studied with TOC,FT-IR and XRD.High crystallinity quartz is the highest content existing in inorganic minerals of Yilan,Huadian and Longkou oil shales,and the kinds of their minerals are varied.Kaolinite exists in Yilan oil shale,while montmorillonite and carbonate minerals in Huadian and Longkou oil shale.In Huadian and Longkou oil shales,there is a combination form of organic matter in montmorillonite layers.Among the three oil shales,some of the soluble organic matter is attached by carbonate minerals and quartz.(2)The total yield of Yilan oil shale soluble portion after thermal dissolution can reach 79.8%.The products from sequential thermal dissolution are mainly composed of aliphatic hydrocarbons,aromatic hydrocarbons,alcohols/phenol,ketone,ether/ester and other compounds,which accounted for 36.9%(27.4%straight chain alkanes,8.7%branched alkanes),5.5%,32.0%,12.7%,5.4%and 7.5%,respectively.At the same time,the identified n-alkanes in total soluble portion exhibit medium long chain aliphatic hydrocarbons,and the distribution ranging from C14 to C30 with maximum values at C16 and C26.(3)The influence of the process conditions on the catalytic hydrogenation of Yilan oil shale was studied.With an increase in reaction temperature,the yield of oil and gas in catalytic hydrogenation increases;with an increase in reaction time,the yield of oil and gas first increases and then decreases;The initial pressure of hydrogen has no significant effect on the yield of oil and gas,which may account for a large amount of hydrogen donor solvent used in the system.The liquefied products of catalytic hydrogenation can be classified into aromatic hydrocarbons,aliphatic hydrocarbons,phenols,ketones and nitrogen-containing compounds,chlorine compounds,alcohols,esters,epoxy ether,aniline,phenol compounds.Phenolic compounds may be derived from the cleavage of phenol ether bonds.