Boiler Parts (Super Heater)

Super Heater

Generally super heaters are used in boiler to increase the temperature of a saturated steam comes from boiler drum. In boiler drum as discuss in earlier blogs number of turbo (Cyclone) separators are working to separate saturated steam and water, water goes to water wall again and again to receive saturated steam condition, this saturated steam now goes to achieve super-heated temperature generally 5400 in a 210 MW capacity boiler by heat transfer from flue gases. The super heaters are classified by their location and temperature range. The steam transfer takes place gradually.
The location of super heater decided in such a manner that temperature difference between steam and flue gases occurs not to high. i.e the temperature of flue gases at low temperature super heater is less then temperature at final super heater.

in a 210 MW boiler there are three super heaters are generally used :

Low Temperature Super Heater (LTSH) : 

LTSH is generally placed in second pass of boiler and above the Economizer, having same type of coil bank as economizer but can be different in size. LTSH Top coils tubes made by Material T-11 and Bottom coil tubes made by Carbon steel, the dimension of both tubes has same (i.e.44*4.5)

The flue gases turn down in second pass comes across the LTSH, Due to high velocity of flue gases, possibility of external erosion increases in this zone hence coil tubes has protected by applying  SS sleeves or cassette baffles.





For more detail click on link below :
http://blog.mechanicsoflife.in/2016/06/boiler-parts-4.html

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