What are the advantages of boiler combustion air preheating ? What are the advantages of boiler combustion air p

What are the advantages of boiler combustion air preheating ?
Combustion air preheaters are similar to economists, because they transfer energy from the flue gases
back into the system. In these devices, however, the energy is transferred to the incoming combustion
air.
* The efficiency is about 1% for each increase in the combustion air temperature by 40 ° F.
* Changes in the combustion air temperature directly affect the amount of combustion air supplied to
the boiler and can increase or decrease the excess air.
* There are two main types: recuperative and regenerative air heaters, tubular or recuperative air
heaters are provided in boilers of medium and small vapor production.
* Steam coil air preheaters are another type. These are used only at the beginning of the boiler to
prevent low temperature corrosion. This air heater does not contribute to improving boiler efficiency,
but is provided to improve availability. It will be seen that during startup, the chances of low
temperature corrosion are high, and therefore the need for the steam coil air heaters is obvious.
* Both economizer and air preheater heat recovery systems in a boiler. If it were not for these heat
recovery systems, today's boilers would operate with much lower efficiency.
* Problems to be taken into account when planning and retrofitting:








sulphur content of the flue gas (dew point corrosion).
flue gas back pressure.
preheating effect on excess O2.
Proposed Actions
flue gas content and efficiency of the boiler
evaluate the possibility and suitable type of heating.
evaluate the economic efficiency of the necessary changes.
system retrofit will provide an average cost with fast ROI.