关键词: 多级孔硅胶吸附剂, 静态吸附法, 动态脉冲法, 芳烃吸附分离, 模拟移动床

Abstract: By employing microporous silica gel powder and silica sol binder in different proportions, hierarchical silica gel adsorbents A–Dwere prepared with the method molding by rolling.The adsorbent mechanical strength and sintered bulkdensity were measured. The pore structure of adsorbent was characterized by gas adsorption method and mercury intrusion method. The adsorption and separation characteristics of the adsorbents for alkanes, aromatics and sulfur-containing compounds were studied by static adsorption and dynamic pulse methods. The research results indicated that the adsorbent obtained microporous, mesoporous, and macroporous structures simultaneously. With the increase of binder content, the mechanical strength of the adsorbent increased and the sintered bulk density decreased. The static adsorption results showed that hierarchical pores in adsorbent would not affect the selectivity of the adsorbent towards aromatic components. With the increase of the binder content, the adsorption capacity of aromatics decreased gradually. The selectivity of adsorbents with different pore structures for aromatics decreased as follows: dibenzothiophene>methyl naphthalene>monocyclic aromatic hydrocarbons>non aromatic hydrocarbons. The dynamic pulse test results showed that the separation resolution of adsorbent B and adsorbent C for aromatic components is comparable to or slightly higher than that of microporous silica gel spheres. Additionally, the mass transfer rates for each component increased by 44.7%–51.5% and 26.1%–32.5%, respectively.. The hierarchical material formed by microporous material obtained a high aromatics adsorption capacity and a large specific surface area, while the mass transfer characteristics were improved and the separation performance of aromatic components was enhanced, which was beneficial for better adsorption and separation performance in simulated moving bed processes.

Key words: hierarchical silica gel adsorbent, static adsorption method, dynamic pulse method, adsorption and separation of aromatics, simulated moving bed