What is the process of superheating in a boiler?

Superheating in a boiler refers to the process of heating steam beyond its saturation point, which is the temperature at which water vapor and liquid water can coexist at a given pressure. When steam is produced in a boiler, it is initially at a saturation temperature that corresponds to the pressure within the boiler. This steam is often referred to as "saturated steam."

The primary purpose of superheating steam is to improve the efficiency of steam turbines, increase the energy content of the steam, and prevent water from condensing in the steam lines. By superheating, the steam retains its gaseous state and can do more work when it expands in a turbine. Higher temperatures generally correlate with higher efficiency in thermodynamic cycles, making superheating advantageous for power generation.

In contrast, other options do not represent the correct process of superheating. Heating water before it enters the boiler relates to the building or maintaining of thermal energy but does not align with the definition of superheating steam. Reducing the pressure of steam is a separate process known as expansion, and while it may affect temperature, it does not provide heat beyond the saturation point. Circulating water within the boiler system contributes to efficiency but is unrelated to the concept of superheating