Boiler superheaters
Boiler superheaters
(OP)
greetings all,
It is my pleasure that I joined a such excellent community for chemical engineers and knowledge sharing.
Regarding the natural circulation boilers, I am just wondering, why there are two super heaters and water spray valve is located between them ? is one superheated not enough to handle the system ?
Thanks,
It is my pleasure that I joined a such excellent community for chemical engineers and knowledge sharing.
Regarding the natural circulation boilers, I am just wondering, why there are two super heaters and water spray valve is located between them ? is one superheated not enough to handle the system ?
Thanks,





RE: Boiler superheaters
- Why do boilers require desuperheaters ? (they are also called interstage attemperators)
- Why are their two segments to the superheater part of a boiler with a desuperheater between ?
Desuperheaters are required in boilers to control final temperature at partial loads.
They have other uses in steam distribution systems just upstream of heat exchangers that operate better with saturated steam.
http://www.s-k.com/pages/pro_08_00.html
There is an excellent discussion of desuperheaters in the classic "Steam" by B&W
MJCronin
Sr. Process Engineer
RE: Boiler superheaters
Saturated steam cannot be attemperated; it has to be somewhat superheated to start with...but if there were only one superheater it would be necessary to superheat the steam well above the desired final temperature before attemperation. This would work, but a single superheater like that would have to be made of more expensive materials to withstand the higher operating temperatures.
Bottom line: add some initial superheat to the steam from the drum, then attemperate as required before admission to the second superheater so as to achieve the desired final temperature. Result? Precise steam temperature control without having to use any more expensive of a superheater material than necessary.
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: Boiler superheaters
RE: Boiler superheaters
In addition to compensating for partial load as mentioned, many boiler tend to foul over time, affecting the S/H outlet temperature. Attemperation is useful in smoothing this out.
RE: Boiler superheaters
We had a very bad experience of a damaged rotor of a 1.5 MW steam turbine due to low quality steam at 360 C and 38 barG.
Steam quality does matter guys :)
RE: Boiler superheaters