Behavior of Magnesium Based Additives Injected into Oil Fired Boilers for as a Preventive Measure Against Gas Side Corrosion

Yoshio Harada, Masaharu Nakamori, Haruo Uera
1985 Corrosion engineering digest  
The behavior of magnesium based additives injected with fuel into boilers was investigated to prevent corrosion caused by molten ash and sulfuric acid. The MgO and Mg(OH)2 additives injected with fuel into the boilers were exposed to high temperature at the combustion furnace burning zone, and then allowed to pass through the high and low temperature superheaters and economizer before being discharged outside the boiler. The furnace pass through rates of MgO and V2O5 were 45 N 50% and 50-60% of
more » ... N 50% and 50-60% of the total injection respectively. In addition, MgO fine particles allowed to pass through the boiler mostly existed in a free state, and there was little MgO reacted with V2O5 and sulfuric acid. Interaction of MgO and V2O5 took place after they deposited on the tubes to form 2 MgO. V2O5 and 3 MgO. V2O5. Besides, it was confirmed that MgO reacted with sulfuric acid in the air preheater, where sulfuric acid existed in a liquid phase. MgO-V205 reaction products were brittle and had high melting point, and they were so poor in adhesion that they were easily removed from the tubes by the soot blower operation. The horizontal boiler, which had the superheaters just above the combustion furnace, had a large amount of deposit containing additive and ash on the furnace bottom. On the other hand the vertical boiler had less deposit on the bottom, because the deposit from the superheaters dispersed to the rear wall tubes.
doi:10.3323/jcorr1974.34.4_240 fatcat:37ecjox6wbfvnbpsdmibvxje2m