Separation And Analysis Of Organic Constituents In Zaozhuang Bituminous Coal

Coal resources are rich in Zaozhuang,Shandong Province,but most of them are used in coking,combustion and other traditional ways.In order to improve the added value of coal utilization and reduce the environmental pollution and greenhouse gas emissions,it is necessary to systematically analyze and study the organic matter composition of Zaozhuang Coal and explore new methods for the utilization of Zaozhuang Coal resources.In this paper,Because of the complex molecular composition of two kinds of Zaozhuang bituminous coal?Daxing coal and Tianchen coal?,it is difficult to get its complete composition information according to a single method,so organic matter was respectively separated from coal by four extraction processes?Soxhlet extraction,ultrasonic extraction,microwave extraction and carbon dioxide supercritical extraction?and an extraction combined with oxygen de-polymerization?UAE/H₂O₂?,and the molecular structure of the products extracted from Zaozhuang Coal under five separation conditions was analyzed in detail,which provided a new idea for the further development of non-fuel use of Zaozhuang Coal.Soxhlet extraction?SE?obtained the least kinds of substances from coal,but SE obtained the most chlorine-containing compounds.The extract of SE from Daxing coal?DX?is mainly composed of chlorinated compounds?76.3%?,among which the relative content of hexachloroethane is 22.95%.Chlorinated compounds?76.4%?were the main content in the extraction of Tianchen coal?TC?,and among which the content of hexachloroethane accounted for 25.54%.The main reason of chlorine-containing compounds in SE was explained and analyzed from the Angle of extraction mechanism.The detected hexachloroethane can prove the free radical formation in the extraction process and provide a new idea for the preparation of hexachloroethane.There are 37 compounds detected from DX in Ultrasonic extraction?UAE?,including 12 aliphatic hydrocarbons and 12 aromatic compounds.The content of hexachloroethane and pentachloropropane in the extract was 10%and10.6%respectively.26 organic compounds were detected in the CCl₄ extraction from TC,including 10 hydrocarbons and 10 aromatic compounds.The content of hexachloroethane in the extract accounted for about 19%.The optimum operating conditions of Microwave extraction?MAE?for Zaozhuang coal under CCl₄ solvent are 80?,8 h,800 W.There are 75 compounds detected in MAE extraction of DX coal.There are 20 hydrocarbon compounds and 22 oxygen-containing compounds in the extraction,and C₂Cl₆ accounted for 11.77%and sulphur compounds for 0.68%.There are 53 kinds of organic compounds that can be detected in the extraction of TC by microwave.Among them,there were 17 pyrenees and 20 oxygen-containing compounds.Hexachloroethane accounts for 19%of the three chlorine-containing compounds.Some biomarker compounds were identified in the extracts of both coals by MAE.A total of 48 organic compounds were detected from DX by SCCO₂extraction with collaborative CCl₄ extraction.Among them,there are 19 alkanes and 7aromatics.The extraction of TC detected 52 organic compounds by SCCO₂.It includes 20 alkanes and 14 aromatics.The biomarkers can be inferred that zaozhuang coal was formed by coal-forming plants in a strong reducing environment.FT-IR?XRD and electron microscopy were used to characterize the residual coal extracted by four extraction processes.In the CCl₄ extraction process of Zaozhuang Coal,the four extraction methods did not destroy the macromolecular structure of the coal.But the microcrystalline structure of coal has changed.The commonality of the four extraction mechanisms is that CCl₄ is induced to generate free radicals under the extraction conditions.The common feature of the four extraction and separation mechanisms is that CCl₄ is induced to produce free radicals under extraction conditions.Chlorohydrocarbons were detected in all CCl₄ extraction products obtained by four extraction processes.The extraction analysis of CCl₄ extraction from the same coal showed that different extraction processes could produce different extraction products,which further proved that the extraction method was also a factor affecting the extraction results.The ultrasonic/H₂O₂ oxidation system of Zaozhuang Coal is favorable for extraction.PE,ether and CS₂ have good extraction effect on the water phase from oxidized,and the petroleum ether extract mainly composed of alkanes and ether extract mainly composed of alcohols has been preliminarily separated.By using PE,CS₂,benzene,methanol and acetone/CS₂ solvents to hierarchical extract the residual coal oxidized by H₂O₂ from Zaozhuang Coal,different solvents with different polarity can effectively enrich different kinds of organic compounds,which not only creates favorable conditions for the fine separation of organic compounds in the residual coal oxidized by coal,but also provides certain information for the study of the macromolecular structure of coal and the effective oxidation of residual coal This study is of great significance to the utilization of non-fuel coal.The existence of C-Cl bond was shown by the infrared spectrum of ultrasonic/H₂O₂ oxidized residual coal in Zaozhuang coal.The weight percentage of Cl in oxidized residual coal is more than 0.37%in SEM-EDS,which indicates that The interaction with coal may involve the formation of chlorinated coal.This paper has 205 references,56 pictures,28 tables.