Abstract: Desulfurization performance of S Zorb unit decreased for obvious difference of particle size and characteristics of sorbents from reactor crossover and sorbent discharging line. Effect of particle size to desulfurization activity of S Zorb sorbent was evaluated in a fixed bed reactor. Results showed that particle size dispersion showed little effect to desulfurization of FCC gasoline. CFD method was used to calculated the effect of particle size,sorbent inventory in reactor,bulk density to the fluidization of sorbent in reactor. Data showed more large size of S Zorb sorbent particle led to lower high of dense bed. In the dilute bed, sorbent particle radius was usually lower than 40μm. Lower sorbent inventory and increased bulk density would lead to the decrease of dense bed level of sorbent in reactor, which was lower than the height of crossover height. Only small size sorbent could be transferred from reactor to regenerator, large size sorbent remained in the reactor and could not be regenerated. This led to an insufficient desulfurization activity of S Zorb process. Based on these results, dense bed level of reactor is raised by adjusting operating conditions and the problem of desulfurization activity was solved.

Key words: S Zorb, adsorption desulfurization, particle size, dense bed, dilute bed