51312-01174-Identification and Testing of Potential Coatings For Use on Walls of Bag House of Flue Gas Desulfuri

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Product Number: 51312-01174-SG

ISBN: 01174 2012 CP

Author: Amal Al-borno

Publication Date: 2012

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Flue Gas Desulfurization results in aggressive conditions in the bag house component of the scrubbers. A test program was conducted to select a coating for corrosion protection in 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°F/86°C) containing water vapor and unreacted CaO SO3 and SO2. Additionally if the external thermal insulation is wet or inadequate the wall temperature is cooled. If the lower 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 upset condition (expected to be 2-4 hours) during which the gas temperature would be approximately 450°F/232°C. Tests included: a) hot immersion / dry heat cycle test using acid immersion (30% H2SO4 solution at 187°F/86°C) and dry heat at 450°F/232°C b) standard atlas cell using sulfuric acid and a thermal gradient across the coating and c) electrical impedance spectroscopy (EIS) to investigate changes in the barrier properties of the coatings in test. Three coatings were selected for testing. 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. Key Words: Flue Gas Desulfurization high temperature protective coatings acid resistant protective coatings Bag House coating tests coating performance.