Question 201Steam Plants - Assistant Engineer

The correct answer is D) temperature differential between the steam and feed water. The rate of heat transfer in a feed water heater is most greatly affected by the temperature differential between the steam and the feed water. This is because heat transfer is driven by the temperature difference, with a larger temperature difference leading to a higher rate of heat transfer. The other factors, such as the speed of the main feed pump, density of the feed water, and pH of the feed water, have a less significant impact on the overall rate of heat transfer in the feed water heater.