A Study On The Process Of Selective Hydrogenation And Conversion Of Heavy Aromatics Raw Oil To Monocyclic Aromatic Hydrocarbons

The purpose of this paper is to study the process of catalytic conversion of aromatics-rich heavy oil diesel fuel fractions to produce monocyclic aromatic hydrocarbons and their derivatives.Because of the high content of polycyclic aromatic hydrocarbons?PAHs?in the heavy aromatic hydrocarbon feed oil?including catalytic cracking light cycle oil?LCO?,heavy crude catalytic thermal cracking diesel?CPP diesel?and coal tar diesel fractions.?,its product value is low.However,it can be used as a low-value raw material for hydrogenation units to produce high-value-added hydrogenated products.The two-step hydroconversion process of hydrotreating and hydrocracking can effectively control the heat generated and the chemical balance,which is beneficial to use heavy aromatic feedstock oil for much more BTX.This article mainly studies the first step,which is the hydrotreating process,to prepare for hydrocracking.This article first screens the above three real oil products using commercial catalyst RS-2100and believes that LCO and CPP diesel are more suitable real oil raw materials for catalyst activity evaluation.Then the catalyst activity evaluation test was carried out under particular conditions with the three homemade catalysts of Cat1#,Cat2#,and Cat3#and the commercial catalyst RS-2100,and it was considered that Cat3#was the best among them as a catalyst that produces more monocyclic aromatic hydrocarbons.The change rule of the CPP diesel hydrogenation reaction is obvious,and it is the most suitable as the raw material for the optimization test.The optimization results of the process condition optimization test are under the conditions of 320?,6.4 MPa,1.0 h^-1,and the hydrogen-oil ratio of 600:1?this process condition is set as the benchmark condition,and the benchmark condition is adopted where not specified in the article?,The conversion rate of polycyclic aromatic hydrocarbons is 86.1%,and the selectivity of monocyclic aromatic hydrocarbons is 77.9%.The optimized results of the twice hydrogenation experiments are the first hydrogenation at 300?,1.0 h^-1,and then at300?,3.0 h^-1,The second hydrogenation,the conversion rate of polycyclic aromatic hydrocarbons is 86.1%,the selectivity of monocyclic aromatic hydrocarbons is 82.5%,and the yield of monocyclic aromatic hydrocarbons is as high as 71.0%as a combination scheme.The optimization result of the competitive adsorption hydrogenation test is that the CPP diesel oil with 5 wt%of sec-butylamine is hydrogenated at 320?with the highest yield of monocyclic aromatic hydrocarbons,the conversion rate of polycyclic aromatic hydrocarbons is 87.6%,the selectivity is 83.8%,and the yield of monocyclic aromatic hydrocarbons is as high as 73.4%.