关键词: 吸附剂, 吸附脱硫, 估算, 多孔介质, 扩散, 孔径分布

Abstract:

Major sulfur components in 0^# diesel conformed to PRC State Standard Ⅱ, Standard Ⅲ and Standard Ⅳ were identified by a gas chromatograph (GC) equipped with a pulsed flame photometric detector (PFPD). The PFPD chromatograms illustrated that benzothiophene (BT), dibenzothiophene (DBT) and their derivatives constitute significant portion of the sulfur species in ORD, majority of which were derivatives of DBT. BT, DBT and 4,6-dimethyldibenzothiophene (4,6-DMDBT) were treated as the characteristic sulfur species in diesel. The hindered diffusion coefficients of characteristic sulfur species in different sizes pore were estimated by a simplified hindered diffusion model. By combining with the stacking pore model of alumina, the appropriate pore size distribution for fuels desulfurization adsorbent was estimated. The results showed that when the average pore diameter of the alumina is 4-10 nm, the hindered diffusion coefficients of characteristic sulfur species were about 0.24 to 0.65 and the specific surface area of the alumina was about 100-250 m²·g^-1, which can meet the lower diffusion resistance and a sufficiently large specific surface area, simultaneously. There was a significant positive correlation between the desulfurization rate of 0^# diesel conformed to PRC state standard II and the percentage of pore area in the range of 4-10 nm. It was preliminary conjectured that the appropriate pore size distribution of alumina-based adsorbent for fuels desulfurization was in the range of 4-10 nm.

Key words: adsorbents, adsorption desulfurization, estimation, porous media, diffusion, pore size distribution