Keywords: flue gas, SO2 removal, copper oxide, regenerable sorbents, sol-gel
Development of durable and reactive regenerable sorbents for high temperature flue gas desulphurisation
One of the emerging technologies for combined SO2 and NOx removal from flue gases is the copper oxide process, which is based on the use of a regenerable sorbent. Sorbent properties such as SO2 sorption capacity, reactivity, crush strength, and long-term durability have significant impact on the overall process cost. In this study, a number of sorbents were prepared by using various modifications of the sol-gel technique. Compared to the commercially available sorbent used for evaluation of the process, sorbents prepared by wet impregnation of sol-gel alumina exhibited comparable sulphur capacity and about seven times higher crush strength, while those prepared by incorporation of copper in the sol resulted in three times higher sulphur capacity and 55% higher crush strength. Significant improvement in long-term durability was also achieved with these sorbents. Preliminary economic evaluation indicates that these new sorbents have the potential to reduce the projected levelised process cost down to 3.17 mil/kWh, which is lower than the cost of current SO2 emission allowance.