Separation Of Phenols And Hydrogenating Removal Of Organic Heteroatoms From Shaanxi Low-Temperature Coal Tar

Low-temperature coal tar(LTCT)is a by-product produced during the coal pyrolysis.It is a black or dark brown viscous liquid with an irritating odor,which is flammable and corrosive.LTCT mainly composed of C,O,H,S and N is a mixture and has a variety of components,such as long-chain alkanes,long-chain olefins,condensed ring aromatic hydrocarbons,phenols and a small amount of tar pitch.Among them,phenols account for up to 10?30%and alkane-like substances account for up to 20%.Phenolic compounds are important chemical products and paraffins are also important liquid fuels.It is of great significance to realize its high value-added utilization.The development of highly active catalysts is the key technology to realize the full utilization of LTCT.In this paper,based on the catalytic reaction of LTCT-related model compounds,the catalytic performance of Ni@Fe₂O₃,Ni@Ce O₂ and Ni/Fe@C and their alkylation in phenol,catalytic hydrogenation of nitrogen or sulfur-containing compounds and the catalytic hydrogenation conversion and reaction mechanism of sulfur compounds.Then,the LP₄ and CAs of the LTCT are catalytically converted.Through the analysis of the obtained solubles,it provides key information for the subsequent utilization and realizes the comprehensive utilization of organic matter in LTCT.In this subject,three supported catalysts were prepared by normal temperature impregnation/in-situ decomposition.The details are as follows:(1)the catalyst precursor is obtained by the normal temperature solvent impregnation method with nickel formate as the active component and Fe₂O₃ nanoparticles as the carrier.Then the nickel formate is decomposing n situ at a lower temperature for preparing highly dispersed catalyst;(2)Ce O₂ nanoparticles is the carrier with nickel formate as the active component and the catalyst precursor is prepared by solvent impregnation-adopting method under the normal temperature for lower temperature in situ decomposition of nickel formate to prepare high disperse easily separable single-atom catalyst;(3)activated carbon nanoparticles is carrier with nickel formate and iron formate as active components and the catalyst precursor is obtained through normal temperature solvent impregnation-adopting method under the lower temperature to decompose nickel formate in situ,like the method of iron formate.A highly disperse easily separated magnetically supported bimetallic catalyst is prepared.First,using dual-solvent extraction technology,the LTCT was firstly separated to obtain LP₄ and CAs,which are tested by FITR,GC/MS and QEOTMS.The LP₄ mainly contains long-chain alkanes,long-chain olefins,condensed ring aromatic hydrocarbons and a small amount of heteroatom-containing compounds.The CAs mainly contains phenolic compounds,which are the high-quality precursor for separating organic chemicals.The dual-solvent extraction of LTCT is a prerequisite for realizing high value-added utilization of LTCT.The properties of catalyst were analyzed with a variety of modern analytical techniques,such as transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),NH₃ temperature-programmed desorption(NH₃-TPD),N₂ adsorption desorption(BET)and laser ablation-inductively coupled plasma mass spectrometry(LA/ICPMS)to characterize the physical and chemical properties between structure and surface properties and catalytic performance.For nickel-based metal catalysts,the active component metal nickel is effectively loaded on the surface of carrier with strong interaction between the active component and the carrier and strong acidity.For the nickel and iron bimetallic catalysts,the two metals are highly dispersed on the surface of activated carbon with strong interaction between the two metals and the carrier,which has a lower loading of Ni and Fe.The catalytic performance and reaction mechanism are explored to screen out suitable catalysts for the catalytic conversion with LTCT-related model compounds as probe molecules,such as phenol,dibenzothiophene and indole.Based on the study of the catalytic conversion:(1)the methylation experiments of phenols are explored with a supported nickel-based,easy separation,and high activity catalyst for the catalytic conversion of CAs,which is analyzed with GC/MS.The results show that only the ortho-methylated products are detected,and the content of 2,4,6-trimethylphenol and 2,3,5,6-tetramethylphenol is much higher than that of LTCT and CAs.It shows that the methylation reaction can efficiently prepare ortho-methylated phenolic compounds,which provides a feasible solution for the subsequent separation and application of phenolic compounds;(2)Catalytic investigation of nitrogen-containing compounds with high-activity single-atom nickel-based catalysts Hydrogen effect.GC/MS analysis results show that the catalyst has a higher effect for removing nitrogen atoms and the hydrogenation of aromatic rings and C-C fragmentation to realize the added-value utilization;(3)investigate the catalytic hydrogenation effect of sulfur-containing compounds with high-activity diatomic metal catalysts.GC/MS analysis results show that the catalyst has a higher effect of removing sulfur atoms,which is a highly active catalyst to achieve high value-added utilization of subsequent separation of LTCT.The above research not only explores the composition characteristics of organic macromolecules in LTCT,but also offers a new way for a directional conversion of organic matter in LTCT under mild conditions to obtain high value-added chemicals and liquid fuels.This thesis contains 63 Figures,26 Tables,and 258 References.