| A huge emission of SO2 from the chimneys of coal combustion boilers is not only a serious environmental problem, but also a great waste of sulfur resource. About 23,7 million tons of SO2 is emitted into atmosphere every year. Regenerative desulfurization process is an effective measure to control air pollution and recover sulfur resource.A novel complex alumina supported calcium oxide and ferric oxide adsorbent was prepared by step wet impregnation method. The desulfurization and regeneration behaviors of this adsorbent were tested at 600C. The results indicate that the sulfur capacity of the adsorbent reaches 7.7 wt%. The adsorbent can be regenerated with CH4, and sulfur is the only regeneration product. The activity maintains as high as 81.3% of the initial activity after four desulfurization-regeneration cycles.The mechanism of desulfurization reaction can be changed by introducing ferric oxide. The ferric oxide is a catalyst of SO2 oxidization. A strong interaction exits between calcium oxide and ferric oxide. The desulfurization behavior is greatly improved by introducing ion into adsorbent. The active components, calcium oxide and ferric oxide convert to calcium sulphate and ferric sulphate during desulfurization, then the sulfates are reduced to obtain calcium oxide and ferric oxide in regeneration.The preparation of the adsorbent was researched. The calcium oxide loading of adsorbent is proportional to the concentration of calcium nitrate in impregnation solution. So the calcium oxide loading can be estimated according to the concentration of impregnation solution within a given concentration range. The optimal ratio of active components Ca to Fe in complex adsorbent is 3:1. The desulfurization rate and sulfur capacity of the adsorbents prepared by step impregnation method are high than those of the adsorbents prepared by mixed impregnation. The optimal temperature of desulfurization is 600 C. At this temperature, the maximal ratio of S/(Ca+Fe) is 0.7 after desulfurization.
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