On a D-type boiler, where is the superheater located?

The correct choice highlights that in a D-type boiler, the superheater is found between the screen and main bank generating tubes. This positioning is significant because the superheater's role is to further heat the steam produced in the boiler before it is sent to the steam system. Placing it here allows it to utilize the heat from the gases exiting the furnace, effectively increasing the efficiency of the steam generation process.

The superheater's location ensures that the steam receives maximum heat transfer from the combustion gases, which have already passed through the screen tubes that primarily absorb heat for initial steam production. This sequence optimizes the boiler's thermal efficiency and ensures that the steam exiting the superheater is at a higher temperature, thus enhancing the performance of steam-driven equipment.

In contrast, other choices either misplace the superheater or refer to components that serve different purposes within the boiler system. The superheater's efficient operation is critical for maximizing the energy output and thermal efficiency of the D-type boiler, thus reaffirming the importance of its correct positioning in relation to other components.