Identification and Testing of Potential Coatings For Use on Walls of Bag House of Flue Gas Desulfurization Process

摘要

Flue Gas Desulfurization (FGD) results in aggressive conditions in the bag house component of the scrubbers. A test program was conducted to select a coating for corrosion protection of the internal surfaces of the bag house. Laboratory tests were developed to simulate the corrosive conditions in the bag house based on the following operating parameters: hot gas (187℉/86°C) containing water vapor and unreacted CaO, SO_3 and SO_2. Additionally, if the external thermal insulation is wet or inadequate, the wall temperature is cooled. If the wall temperature is below the internal process dewpoint, sulfuric and sulfurous acid are formed from water condensation on the wall due to the sulfur species in the flue gas (estimated concentration: 30%). The last parameter that the testing must mimic is a dry heat during an upset condition (expected to be 2-4 hours) during which the gas temperature would be approximately 450℉/232°C. This paper presents details of, and results from, the laboratory testing in which one of the three coatings showed good resistance to the conditions and was selected for use in the bag house.