介孔硅胶在柴油氧化-吸附组合脱硫中的应用研究
Application of mesoporous silica gel in desulfurization of diesel oil via oxidation-adsorption process
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摘要: 以硅胶(SG)为吸附剂,采用自制的双亲催化剂与H2O2组成的催化氧化体系将柴油进行氧化,利用固定床动态吸附法考察了硅胶性质、氧化过程及吸附条件等对硅胶吸附脱硫性能的影响,并对硅胶进行了表征。小角XRD和氮气吸脱附结果表明,实验所用硅胶具有介孔结构。吸附脱硫实验结果表明,在油剂比(柴油与吸附剂的体积比)相同时,氧化-吸附脱硫过程脱硫率明显高于吸附脱硫过程脱硫率;选用硅胶作吸附剂,吸附温度为40℃,吸附空速为6.0 h-1时脱硫效果较好,当油剂比为1时,脱硫率高达94.57%,且该介孔硅胶具有较大的吸附硫容,随油剂比增大下降缓慢,当油剂比增大到15时,脱硫率仍达85.89%。Abstract: The desulfurization of diesel oil was conducted via oxidation-adsorption process, using H2O2 as oxidant in the presence of amphiphilic catalyst and mesoporous silica-gel as the adsorbent. The fixed-bed dynamic adsorption method was employed to evaluate the oxidation-adsorption desulfurization capability of the catalysts and the effects of the property of silica-gel, oxidation and adsorption conditions on desulfurization efficiency were investigated. It was proved that the silica-gel possessed the mesoporous structure characterized by small-angle XRD and N2 adsorption-desorption isotherm. Compared with adsorption process, oxidation-adsorption process could availably increase the adsorptive capacity and selectivity of silica-gel adsorbent to sulfur compounds in diesel oil.The sulfur removal efficiency remained as high as 85.89% when the volume ratio of diesel oil to silica-gel was 15. Sulfur removal efficiency reached up to 94.57% when adsorption temperature, space velocity and volume ratio of diesel oil to silica-gel were 40℃, 6.0 h-1 and 1 respectively.