How close is boiler feed water typically heated to boiler water temperature?

Boiler feed water is typically heated to a temperature that is relatively close to the boiler water temperature to improve efficiency and prevent thermal shock. It is common practice to heat boiler feed water within 20°C of the boiler water temperature. This close temperature gradient helps to minimize the formation of thermal gradients that can lead to stress and damage in the boiler materials.

By maintaining the feed water temperature within this range, the overall efficiency of the boiler system is enhanced, as warmer feed water requires less energy to convert to steam. Furthermore, it reduces the risk of condensation, which can be detrimental to both boiler performance and longevity. While heating within a narrower range may offer benefits, the standard operating practice accepts a variation of up to 20°C to effectively balance efficiency and equipment integrity.