Abstract: During the operation of oil-fired boiler, some problems occurs frequently such as high temperature corrosion of heating surface, ash deposition on heating surface, low temperature corrosion of air preheater and tail flue, and so on. Reasonable usage of magnesium oxide additive can effectively solve the above problems. Mechanisms, performance and application characteristics of above two kinds of fuel additives, i.e., Sunricho-EM330 and Sunricho-OM20 are introduced. In the heavy-oil fired boiler using fuels with high content of vanadium and sulfur, the two kinds of fuel additives are applied for the comparison test. The proper amount for the fuel additives are determined in test. Both of the additives have effect on anti-corrosion of heating surface, enhancing PH vale, and decreasing the dew point of flue gas. However, long term usage of additives will bring the fouling problem for the boiler as it could bring more ash. Heating surface inspection and ash analysis are performed when boiler is shut down. Sticky deposit is found in the inner layer of ash. To achieve the same target of anti-corrosion, OM20 exhibits more advantages with less amount of OM-20 needed but better performance in fouling.

Key words: oil-fired boiler, fuel additive, corrosion, fouling