Question 18Steam Plants - Assistant Engineer

The correct answer is B) proper combustion of the fuel oil. The 12% to 14% content of carbon dioxide in boiler flue gases indicates that the combustion of the fuel oil is occurring properly. This range of CO2 content suggests that the fuel is being burned efficiently, with the right amount of air to achieve complete combustion without excessive excess air. The other options are incorrect because: A) too much excess air would result in lower CO2 levels, C) high vanadium content does not directly affect the CO2 levels, and D) carbon deposits would not necessarily indicate the CO2 content in the flue gases.