Abstract: A liquid borate is added to sulfur trioxide-containing combustion gases at a temperature of from about 250.degree. to about 1000.degree. F. in a boiler or other furnace system. The borate neutralizes sulfuric acid in the gases and inhibits sulfuric acid corrosion and deposition on metal surfaces of the system that contact the gases. An organic deposit modifying agent such as sorbitol and an additional acid neutralizing agent such as an alkali metal hydroxide, aluminate, or silicate may also be added to the combustion gases.

Abstract: A composition containing a hydroxylamine compound; a quinone, a dihydroxybenzene, a diaminobenzene, or an aminohydroxybenzene compound; and a neutralizing amine is an excellent oxygen scavenger and corrosion inhibitor in boiler water and other aqueous systems.

Abstract: The accumulation of scale in an aqueous system is inhibited by the addition of a copolymer of maleic acid or anhydride or fumaric acid and allyl sulfonic acid and a water soluble organic phosphonic acid such as aminotri(methylene phosphonic acid), ethylenediaminetetra(methylene phosphonic acid), hydroxyethylidene diphosphonic acid and 2-phosphonobutane tricarboxylic acid-1,2,4 or water soluble salts thereof. Scale can actually be removed by the addition of these materials to pressurized boiler water systems. Allyl or vinyl copolymers, a phosphonate, and optionally a water soluble, hardness precipitating agent such as a carbonate or a phosphate may be used when treating pressurized boilers to provide an in-service cleaning effect.