ASME standard steam superheater tubes of a high pressure boiler Chinese product
Superheater Working Principle
1. Superheater is a subcritical boiler’s component that heat the saturated vapor, at constant pressure, so it becomes superheated steam.
2. Superheater technology has been used since the use of steam engines early 20th century. The main purpose is to increase the heat energy contained by the steam, so that increasing the thermal efficiency of the engine.
3. Until now the use of superheater is still very popular, especially in large water-tube boiler steam power plant.
Boiler Superheater in details
1. The superheater can be divided in two sections, primary and secondary, as in the boiler studied, where the superheater tubes are within the radiation zone. After nineteen years of service, the primary one showed some tube deformation, which had become greater when observed at the last inspection/maintenance shut downs.
2. This residual plastic deformation was observed on the outlet tube, attributed to differential dilatation, because of different temperatures, between the last two tubes, anchored by spacers, and causing buckling.
3. After that, in December 2001, when the boiler had twenty three years of service, a stress and metalographic analysis was made on an assembly removed from the boiler, involving yet dimensional inspection, nondestructive testing, hardness measurement and deposit examination.
Advantages of superheated steam (super heaters)
1. Work output is increased for the same quantity of steam.
2. Loss due to condensation of steam in the steam engine and is the steam mains is minimized.
3. Capacity of the plant is increased.
4. Thermal efficiency is increased since the temperature of superheated steam is high.