Discussion Of The Structural Properties Of Shenhua Coal Direct Liquefaction Residue

Coal direct liquefaction will be taken into commercial application, but the properties of residue have been little researched. Therefore, in this paper, the structure characters of Shenhua coal direct liquefaction residue have been studied. In order to deal with and utilize the residue, the systematical study of the physical and chemical properties of the residue could provide basic data for its utilizations in the future.The residue has been separated into four fractions by using solvent extraction, that is, the oil(HS), asphaltene(HI-BS), preasphaltene(BI-THFS) and the insoluble of tetrahydrofuran (THFI), which have been studied respectively.In this paper, not only routine analyses, such as elemental, molecule weight etc., but also fourier infrared spectrometry, nuclear magnetic resonance spectrometry and pyrolysis GC-MS and so on have been used. The characters of three organic fractions have been obtained by analyzing the much data and information from above instrumental analyses. The emphasis in this paper is the molecular structure of the oil and asphaltene fractions, including the species and characters of the functional groups, the main structure units of intra-molecule and distributions of carbon and hydrogen atoms. The oil and asphaltene fractions contain more than forty kinds of structure fragments, including 1～4 rings (6 rings for asphaltene) of condensing aromatic and partially hydrogenated aromatic structure units, as well as a series of n-alkane chain that are linked with aromatic structure. Average molecule structure model of the oil and asphaltene fractions have been drawn out, in according to colligating the data of instrumental analysis and calculating average structure parameters of the two fractions. The properties of preasphaltene have been partially studied.In addition, polymers of tetrahydrofuran have been found in the pyrolysis GC-MS analysis of the asphaltene fraction, which has been shown that polymerization of tetrahydrofuran has occurred in the course of solvent extraction.For the insoluble of tetrahydrofuran, using microscopy analysis and X-ray diffraction analysis, it has been found out that a part of the mineral substances in feed coal have become sulphates as well as the active forms of catalyst are 8 kinds of crystal structures of Fe_1-xS.