Sizing For A Boiler Blowdown Tank? 2

[BuddyUSC]

Hey everyone,

First post, so here it goes.

I'm having trouble in finding how to choose the correct size for the tank. I recently did research on Flash Tanks and found sizing information on them was very readily available, but it is quite the opposite for blowdown tanks. My first thoughts were that the size of the tank would correspond to the boiler (pressure, flowrate, volume) but I could very well be way off-base, as this is my first time dealing with boilers and boiler applications.

Any help is very much appreciated!

-Buddy

 

[Latexman]

Do you know how to use Google?

Sizing Blowdown Tanks

Good luck,
Latexman

 

[BuddyUSC]

I was up and down Google trying to find something like this. If it's easy, I will, of course, find a way to make it more difficult. Thank you so much!

-Buddy

 

[sspeare]

You can use the attached file as a starting point, to size the blowdown tank. It is a page from Cleaver Brook's literature for a SPECIFIC BOILER: model CFV. Note - the page says: "The National Board's recommendations base the size of the blowdown tank on the removal of at least 4 inches of water from the boiler."

So, be careful. Find out from your boiler manufacturer how much water it takes to lower the level by: 4 inches?, or should it be some other value per the mfr????

Always check with the boiler mfr. Do not guess.

 

[Shmulik]

This subject has already been discussed here
thread124-125547
thread124-277326
thread794-280630

 

[Darren6060]

For blowdown tank sizing - I use Canadian Code CSA B51-09 Boiler Pressure vessel and pressure piping code.

Table 1 defines the design pressure for blowoff vessel
Max boiler pressure 15-300 psi use 30% of max boiler pressure but shall be at least 15 psi

Over 300 psi max boiler pressure use 100 psi.

Table 3 defines size
foe example 25000 lb/hr boiler use 42" dia x 40 ft3 volume