Enhancement of sorbent utilization in fluidized-bed combustion

✍ Scribed by Ralph T. Yang

• Publisher: Elsevier Science
• Year: 1978
• Tongue: English
• Weight: 395 KB
• Volume: 57
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/0016-2361(78)90027-3

✦ Synopsis

A new, simple and non-corrosive method is described which can substantially reduce the lime requirement in fluidized-bed combustion of coal. The method entails spraying the limestone particles before they are fed to the combustor with an aqueous solution of iron (ferric and/or ferrous) sulphate and/or sulphite. These compounds rapidly decompose in the environment of the combustor and Fe203 is deposited on the lime surface. Small amounts of Fe203 deposited in this manner substantially catalyse the rate of SO;! uptake. For example, 1.4% Fe203 on Greer limestone nearly doubles the rate. The catalysis would translate into a calculated reduction of the lime requirement by over 40%, although direct translation would require large-scale testing. The basis of the catalysis is that Fe203 catalyses the oxidation of SO2 to form SO-J. The SO;! capacity of the limestone is also enhanced. This simple technique may also be applied to various hot-gas desulphurization processes, such as those with the dry scrubbers, and to other SO;! sorbents.