Catalytic Hydroconversion Of Two Coals In Residue Over A Magnetic Superacid Catalyst

Coal resources are the foundation of national economic development,in order to better realize the use of high value-added coal.One of the key points is to prepare highly efficient coal conversion catalysts,and the other key is to find suitable hydrogen supply sources,such as coal-based and petroleum-based residues.Based on the above theory,the Ni/C composite material obtained by calcining nickel-based metal organic frameworks（Ni-MOFs）was used as a carrier,and the magnetic solid super acid catalyst TFMSA@Ni/C was prepared by the impregnation method.The characterization results prove that trifluoromethanesulfonic acid（TFMSA）is successfully loaded on the support Ni/C,the distribution is uniform and there is no obvious agglomeration.At the same time,TFMSA@Ni/C can be absorbed by magnets and separated from the experimental system for recycling.The coal-related model compound Dibenzyl ether（OBMDB）was selected to investigate the catalytic performance of the catalyst,determine the optimal reaction conditions,and infer the reaction mechanism.In order to study the hydrogen supply effect of different residues in different systems,Xinjiang Runbei Lignite（RL）and medium and low temperature coal tar（MCT）,Shaanxi Weiqiang bituminous coal（WBC）and petroleum deep cracking heavy oil（DCC）were selected.Choose cyclohexane-ethanol（1:1,v/v）solvent with the highest solubility for both residues to explore the synergistic effect of residues in the conversion of coal and optimize the reaction conditions.Experiments were performed on the RL+MCT system.Under the same conditions,RL and MCT with 0 or 10%RL mass were co-melted,and a synergistic effect was determined.The GC/MS composition of SP_NCHC-RL and SP_NCHC-RL+MCT was analyzed.It was found that after the addition of MCT,the relative content of several types of compounds such as branched alkanes,alkenes,alkynes,cyclanes and aromatic hydrocarbons all increased,and the types of phenol and its alkyl substituents increased while the relative content decreased.It is speculated that the above results come from the hydrogen supply of residue MCT.The catalyst TFMSA@Ni/C were used to perform catalytic hydroconversion experiments on RL+MCT system and optimize the reaction conditions.The experiment proves that the conversion rate of RL reaches the maximum under the conditions of 310 ^oC,4 h,and 4 MPa H₂ in 10%RL mass MCT.Comparative analysis of the GC/MS spectra of SP_NCHC-RL+MCT and SP_CHC-RL+MCT.The relative contents and types of cyclanes in SP_CHC-RL+MCT have increased significantly,while the branched alkanes and other heteroatomic compounds have decreased.The conversion experiment of WBC+DCC was performed.WBC was hot-melted in DCC with 0 or 10%WBC quality.Analysis of the conversion rate of WBC showed that the co-treatment of WBC and DCC also had synergistic effects,but the improvement was weak.The GC/MS spectra of SP_NCHC-WBC and SP_NCHC-WBC+DCC were compared and analyzed.After the addition of DCC,the relative content of branched alkanes,alkyl-substituted benzenes,and alkyl-substituted phenols decreased,and new cycloalkanes appeared.It is speculated that the above is the result of C—C bond cleavage and recombination in some macromolecular linear alkanes after adding DCC.The catalytic conversion experiments of WBC+DCC were performed under the action of the catalyst TFMSA@Ni/C.and its conversion rate is significantly higher than that of the system under non-catalytic conditions.The experimental conditions such as temperature,pressure and time were changed,and the optimal reaction conditions were 5%WBC mass DCC,310 ^oC,4 h and 4 MPa H₂.Analysis of the GC/MS spectra of SP_NCHC-WBC+DCC and SP_CHC-WBC+DCC.After catalysis,the relative content and species of cyclanes increased significantly,while the relative contents of branched alkanes and other heteroatoms decreased.The catalyst TFMSA@Ni/C catalyzed a macromolecular aromatic oxygen-containing compound in the system to undergo bond breakage,recombination,and ring formation.At the same time,DCC contained more condensed-ring aromatic hydrocarbons and alkenes,which corresponded to the catalytic action of the catalyst at high temperature and pressure,so that hydrogen in the bond release promotes the catalytic hydrogenation of the WBC+DCC system to obtain more cyclanes in the coal.There are 42 figures,66 tables and 88 references in this thesis.