A study on regeneration of Mn-Fe-Zn-O supported upon gamma-Al_2O_3 sorbents for hot gas desulfurization

摘要

In this study, the regeneration conditions of Mn-Fe-Zn-O supported upon gamma-Al_2O_3 sorbents for high-temperature desulfurization of fuel gases were investigated. Mn-Fe-Zn/gamma-Al_2O_3 sorbents with Mn/Fe/Zn molar ratio of 2:1:0.2, AMFZ0.2, were prepared. Desulfurization and regeneration were carried out in a quartz fixed-bed reactor of 10-mm diameter. Sulfidation tests were performed at 650 deg C using the gas mixture containing (mol) 0.3%H_2S-11.62%H_2-19.34%CO-6.85%CO_2-61.84%N_2 at SV=3000 h~-1. Sulfur capacity of the fresh sorbent was about 5.3 gS/100 gSorbent. Regeneration parameters including temperature, concentration of oxygen, space velocity and steam content have been considered in order to obtain suitable regeneration conditions. The regeneration was performed at the following parameters-pressure: atmosphere, temperature: 600-750 deg C, space velocity: 2000-3000 h~-1 and gas composition (vol.%): 2-8 O_2, 4-10 H_2O with N_2 balance. Typical properties of the sorbents before and after regeneration were characterized using XRD, SEM, BET and ICP methods. The most suitable regeneration conditions were obtained including 700 deg C of regeneration temperature, 6.0% of oxygen content and 8.0% of steam in the gas stream.