What purpose does tertiary combustion air serve in a furnace____________________?
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Answer: E. convert CO (formed in lower zone of furnace) into C02 at higher zone
Explanation
Tertiary combustion air is introduced into the upper furnace zones to complete the oxidation of carbon monoxide (CO) into carbon dioxide (CO2). Injecting air at higher levels ensures complete combustion of unburned gases escaping from the primary combustion zone. This staged combustion approach maximizes thermal energy release while minimizing harmful carbon monoxide emissions in boiler exhaust. Large industrial boilers utilize staged combustion air systems, categorized as primary, secondary, and tertiary injection streams. Carbon monoxide forms during incomplete combustion when insufficient oxygen is present in the lower fuel-rich furnace regions. Complete oxidation of CO to CO2 releases additional exothermic heat and improves overall boiler combustion efficiency.
Providing air around burners for optimum combustion is the primary function of secondary air rather than tertiary air. Transporting and drying raw coal prior to combustion is handled by primary air and pulverizer mill systems. Cooling instrumentation scanners is typically accomplished using dedicated high-pressure cooling air blowers rather than combustion air.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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