Abstract: The present invention provides a composite layer agglomerating adsorbent, comprising an outer adsorbent layer containing a low silica X molecular sieve and an inner adsorbent layer containing a high silica X molecular sieve, the low silica X molecular sieve has a silica/alumina molar ratio of 2.07-2.18, the high silica X molecular sieve has a silica/alumina molar ratio of 2.2-2.5, based on the total amount of the adsorbent, the adsorbent comprises 95.0-100 mass % of the X molecular sieve and 0-5.0 mass % of the matrix, the cation sites of the X molecular sieve in the adsorbent are occupied by a metal of Group IIA or occupied together by a metal of Group IA and a metal of Group IIA. The adsorbent is suitable for the process of adsorptive separation of PX from C8 aromatic hydrocarbons using light aromatic hydrocarbons as desorbent, and has high adsorption selectivity and good mass transfer performance.

Abstract: A m-xylene adsorbent contains 94 to 99.9 wt % of a Y molecular sieve and 0.1 to 6 wt % of a matrix. The Y molecular sieve consists of a non-crystal-transformed Y molecular sieve and a Y molecular sieve produced by a crystal transformation. The non-crystal-transformed Y molecular sieve is a mesoporous nano Y molecular sieve, which has a crystalline grain size of 20 to 450 nanometers, contains two types of mesoporous pores, and respectively has most probable pore diameters of 5 to 20 nanometers and 25 to 50 nanometers. The adsorbent is used for adsorptive separation of m-xylene from mixed C8 aromatic hydrocarbons.

Abstract: A process for producing para-xylene and ethylbenzene from C8 aromatics containing ethylbenzene includes the steps of sending C8 aromatics containing ethylbenzene to an ethylbenzene liquid-phase adsorption separation device, wherein a suction liquid containing ethylbenzene and a suction residual liquid are obtained after the adsorption separation, and the desorbents in the suction liquid and the suction residual liquid are removed to obtain ethylbenzene and a suction residual oil; sending the suction residual oil to a para-xylene adsorption separation device, and unadsorbed components are discharged as a raffinate from the adsorbent bed; the adsorbent bed is rinsed with a desorbent to desorb the para-xylene therein and obtain an extract; the desorbents in the extract and the raffinate are respectively removed to obtain para-xylene and a raffinate oil; sending the raffinate oil to a xylene isomerization device to carry out xylene isomerization, and the isomerization product is fractionated.

Abstract: A process for producing para-xylene and ethylbenzene from C8 aromatics containing ethylbenzene includes the steps of sending C8 aromatics containing ethylbenzene to an ethylbenzene liquid-phase adsorption separation device, wherein a suction liquid containing ethylbenzene and a suction residual liquid are obtained after the adsorption separation, and the desorbents in the suction liquid and the suction residual liquid are removed to obtain ethylbenzene and a suction residual oil; sending the suction residual oil to a para-xylene adsorption separation device, and unadsorbed components are discharged as a raffinate from the adsorbent bed; the adsorbent bed is rinsed with a desorbent to desorb the para-xylene therein and obtain an extract; the desorbents in the extract and the raffinate are respectively removed to obtain para-xylene and a raffinate oil; sending the raffinate oil to a xylene isomerization device to carry out xylene isomerization, and the isomerization product is fractionated.

Abstract: The present invention provides a composite layer agglomerating adsorbent, comprising an outer adsorbent layer containing a low silica X molecular sieve and an inner adsorbent layer containing a high silica X molecular sieve, the low silica X molecular sieve has a silica/alumina molar ratio of 2.07-2.18, the high silica X molecular sieve has a silica/alumina molar ratio of 2.2-2.5, based on the total amount of the adsorbent, the adsorbent comprises 95.0-100 mass % of the X molecular sieve and 0-5.0 mass % of the matrix, the cation sites of the X molecular sieve in the adsorbent are occupied by a metal of Group IIA or occupied together by a metal of Group IA and a metal of Group IIA. The adsorbent is suitable for the process of adsorptive separation of PX from C8 aromatic hydrocarbons using light aromatic hydrocarbons as desorbent, and has high adsorption selectivity and good mass transfer performance.