Boiler air preheater and feedwater preheater
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What is the difference between a boiler’s air preheater and a feedwater preheater? Is the installation method the same? I would like to ask boiler experts for their advice. Thank you
Both of these devices make use of the waste heat from the flue gases generated after boiler combustion. The difference is that an air preheater, as the name suggests, is used to preheat the temperature of the air used for burning in the boiler ； A feedwater preheater is used to preheat the temperature of the boiler feedwater. Considering the dew point corrosion issue that may arise from the recovery of low-temperature waste heat from flue gas, the boiler feedwater preheater is generally placed at the front end of the flue gas outlet, while the air preheater is placed at the rear end of the flue gas outlet. Because the water pipes in the feedwater preheater are under high pressure, while the pressure difference between the flue gas and air in the air preheater is very small; therefore, any corrosion-related leakage will not cause a serious accident.
This post was last edited by zgj2405 on 2012-1-31 at 13:10. Air preheaters are generally located near the chimney, serving to preheat the air used for combustion. Boiler feedwater preheaters are used to preheat the water in the boiler; they are usually placed upstream of the flue gases to recover waste heat.
For boiler air preheaters, has anyone used plate-type air preheaters? This is the mainstream now.