Study on Modified Y Zeolites and Their Behaviors in Selective Adsorptive Desulfurization of FCC Gasoline (I)

NaY zeolite was modified through dealumination with oxalic acid, and the HY zeolite was obtained by calcination of the modified NaY zeolite. The zeolite molding process was carried out at ambient temperature (25 degrees C), and the influence of solid/fuel mass ratio and adsorptive desulfurization time on the HY zeolite were investigated through tests on static selective adsorptive desulfurization of FCC gasoline containing organic sulfur compounds (with a S content=135 ppm). The sulfur content and sulphide types in the FCC gasoline were analyzed by a GC 2010 sulfur analyzer and a GC-SCD chromatograph. The test results showed that the molded HY zeolite was better than the unmolded HY zeolite. At a static adsorptive desulfurization time on the molded HY zeolite equating to 6 hours, a solid/fuel mass ratio of 1:3, the sulfur content of FCC gasoline was decreased to 30 ppm, and the desulfurization rate was equal to 78%. When the breakthrough point of the molded HY was equal to 50 ppm, the molded HY zeolite was capable of adsorbing 4.86 mg of sulfur per gram of adsorbent. And the regeneration rate of molded HY zeolite was equal to 98%.