The superheater boiler produces superheated or dry water vapor. This steam stores more heat energy than saturated water steam, characterized by higher enthalpy values. The steam produced by conventional boilers generally only reaches the saturated phase, but in this superheater boiler, saturated steam will be heated further to reach the superheated phase. In addition to storing greater heat energy, superheater boiler removes the dampness of saturated steam.
The main advantage of using a superheater boiler is to increase the boiler efficiency, so it can reduce fuel and water consumption. But on the other hand, there are additional costs required for the erection and maintenance. Since the superheater boiler works at high pressure and temperature, it is using higher pipe quality than conventional boilers.
The superheater boiler at the beginning of its emergence is used on steam trains. And then more widely used for the needs of steam power plants. The size also depends on the needs of steam consumption, 640 megawatts of power plants for example using a superheater boiler with steam production of about 1800 tons per hour.
Supercritical boilers produce supercritical steam. This boiler is called supercritical because it operates above the critical pressure and temperatures, which is 3,200 psi and 647 Kelvin. In contrast to a superheater boiler that requires a device to separate water vapor with a mixture of steam and water (usually called steam drum), supercritical boilers do not need it. During the process of supercritical steam formation there will be no transition phase from liquid water to steam. This leads to less fuel consumption, and further reduces CO2 gas emission. Actually the term boiler is not appropriately used in supercritical boilers, because in the process does not occur boiling process in it. So that supercritical boiler better known as supercritical steam generator.