Concept of Steam Generation
Muhammed Zakiy K
Mechanical Engineer with 12 years of experience in the Conventional Power Generation Industry
Steam generation is the process of converting the water into steam (vapor) by application of heat. Heat can be applied at any pressure which causes the water to boil and release the steam.
Common terms used in steam generation
Sensible Heat:
It is the amount of heat energy required to bring the water from 0 deg.C or atmospheric temperature to the boiling point. Amount of sensible heat required is proportionate to the pressure at which heat energy is applied. The heat energy is measured in terms of kCal/kg.
Latent Heat:
When the water starts boiling, the phase change takes place (i.e from water to steam). In this region the temperature remains constant. In this region both water and steam mixture will be available (i.e wet steam)
Super Heat:
When the water gets converted into steam completely (saturated steam) the temperature starts rising. Heat energy supplied beyond the latent heat region is called the super heat.
Saturation Temperature:
The temperature at which the water starts boiling during the application of sensible heat is called the saturation temperature. The boiling point varies with the pressure at which the heat energy is supplied.
Critical Point:
When the amount of pressure for steam generation increases, the sensible heat also increases, with decrease in the latent heat. At a certain pressure, the water directly converts into steam without going through the phase of wet steam. This occurs at 374 deg.C and 221.6 kg/cm2 pressure. This is called the critical point.