What component of a water tube boiler controls the flow of air to the burners to maintain the correct fuel-to-air ratio?
A. Air register
B. Draft fans
C. Desuperheater
D. Burners
A. Correct. Air registers control the flow of air to the burners to maintain the correct fuel-to-air ratio and to reduce smoke, soot, or NOx (nitrogen oxide) and CO (carbon monoxide) formation.
B. Incorrect. Draft fans are used to supply combustion air to the burners.
C. Incorrect. A desuperheater is a temperature control point at the outlet of the boiler steam flow that maintains a specific steam temperature by using boiler feedwater injection through a control valve.
D. Incorrect. Burners are devices that introduce, distribute, mix, and burn a fuel for heat.
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