Question 82Steam Plants - 1st Asst/Chief

The correct answer is C) proper combustion of the fuel oil. A carbon dioxide (CO2) content of 12-14% in boiler flue gases typically indicates that the fuel oil is being properly combusted. This level of CO2 suggests the combustion process is optimized, with the right amount of air mixing with the fuel to achieve complete and efficient burning. The other answer choices are incorrect because: A) high vanadium content would not affect the CO2 levels, B) carbon deposits would likely lead to incomplete combustion and lower CO2 levels, and D) too much excess air would dilute the flue gases and result in lower CO2 concentrations.