Dry Regenerable Metal Oxide Sorbents for SO2 Removal from Flue Gases. 1. Development and Evaluation of Copper Oxide Sorbents

The reactivities of a number of copper-based sorbent prepared by the sol-gel method toward SO2 were determined in a thermogravimetric analyzer as well as a fluid-bed reactor. The copper content of these sorbents ranged from 11.2 to 26.5%. The highest sorbent capacity was achieved with sorbent with copper content of 14.1%. All these sorbents have significantly higher mechanical strength than commercially available copper-based sorbents and commercial fluid catalytic cracking catalysts (i.e., 5-8 times higher), making them suitable for fluidized-bed applications. The reactivity of the sorbent increases with increasing temperature up to 450 °C, and starts to decrease significantly beyond 500 °C, possibly due to sintering of the sorbent. Although these sorbents can be readily and completely regenerated with natural gas, the overall sulfur capacity of the sorbents gradually decreases in the cyclic operation and appears to stabilize after about 20 cycles, making them suitable for regenerative flue gas desulfurization applications.