Which effect will a low boiler economizer outlet temperature have on the boiler superheater outlet temperature?

A low boiler economizer outlet temperature will cause the boiler superheater outlet temperature to increase. This is because the economizer is designed to preheat the feedwater before it enters the boiler, thereby improving overall efficiency. When the economizer outlet temperature is low, it implies that the feedwater entering the boiler is cooler.

As the cooler feedwater is heated by the combustion gases within the boiler, it will require additional heat input to reach the desired temperature for steam generation. Consequently, the super heater, which further increases the temperature of the steam beyond the saturation point up to the desired superheated steam condition, will need to work harder, effectively raising the superheater outlet temperature in response to the lower entering temperature from the economizer.

Maintaining a balance in these temperatures is essential for optimal boiler performance, and a lower economizer outlet generally requires adjustments in the superheater to compensate for the reduced effective heating of the steam.