The adsorptive separation of heavy aromatics from fuel fractions yields is an efficient way to utilize surplus gaso-line and diesel resources in refineries.The non-aromatic products can be used to increase the production of low-carbon ole-fins through steam cracking or catalytic cracking processes.The aromatic products are mainly composed of mono-aromatics,which can be turned into good feedstocks for ethylene production and light aromatics like benzene,toluene,and xylene through the heavy aromatic lightening technology.The hydrogen solubility was measured using adsorption separation of heavy aromatic hydrocarbon components as raw materials.The solubility of H2 in the heavy aromatics was between 1.0×10-4～3.2×10-4 mol/g,and increased with temperature and H2 pressure.It was 1～2 order of magnitude lower than that needed for the hydrogenation of ploy-aromatics to mono-aromatics.The effects of the reduction temperature of catalyst precursor,the as-pect ratio of fixed-bed reactor,the reaction temperature,the H2 partial pressure,the H2-oil ratio,and the weight hourly space velocity(WHSV)on the lightening of heavy aromatics obtained by adsorptive separation from a diesel fractions over a NiMo/β catalyst were also studied.Over the catalyst prepared by reduction of the precursor under relatively low temperature and high pressure(350 ℃ and 4 MPa),the optimal reaction conditions were aspect ratio of 4.5,reaction temperature of 400～410 ℃,H2 pressure of 5.0～5.5 MPa,H2-oil ratio of 800～1000,and WHSV of 1～1.5 h-1.Under the conditions,the conver-sion of the C10+compounds was above 85％,while the yield and the purity of C6～C9 aromatics were more than 50％and 97.5％,respectively.The coupling of diesel adsorptive separation and the lightening of the obtained heavy aromatics to light aromatics greatly improved the yields of chemicals from diesel fractions,which made broad application prospect and enor-mous practical significance.
adsorption separation process of aromaticsdiesel aromaticheavy aromatics to light aromaticaromatic yieldH2 solubility
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