Method for controlling the oxidation of sulfites in a flue gas desulfurization process

摘要

This invention relates to, for use in a flue gas desulfurization process wherein sulfur oxide-containing exhaust gas is treated with an absorbing fluid containing a calcium compound, and an oxygen-containing gas is passed through the absorbing fluid containing the resulting calcium sulfite to oxidize the calcium sulfite and thereby form gypsum, a method for controlling the oxidation of sulfites which comprises the steps of continuously detecting a first deviation signal between the oxidation-reduction potential (ORP) of the absorbing fluid and the ORP of the absorbing fluid in a completely oxidized state by means of an ORP detector equipped with a sample fluid tank for detecting the ORP of the absorbing fluid and a reference fluid tank for oxidizing the absorbing fluid by the passage of air therethrough and detecting the ORP of the absorbing fluid in a completely oxidized state, and controlling the flow rate of the oxygen-containing gas in response to a second deviation signal between the first deviation signal and a preset ORP deviation value, which the ORPs are detected by using an ORP detector equipped with a plurality of reference fluid tanks and making measurements while successively switching the reference fluid tanks.