Steam Desuperheater Sizing

[pflow]

Please inform me of a method to determine the diameter and height of a steam desuperheater vessel.

Superheated steam will be injected into the vessel in a sparger and mixed with cooling water injected into the bottom of the vessel.

 

[danberry]

Usually desuperheating is done by injecting water in the steam line, not by sparging steam under water.

Sparging superheated steam in water can rattle the vessel and piping quite a bit. You would be better off misting water at the top of a steam filled vessel, if you really cannot use a purpose built desuperheater.

Desuperheating is deceptively simple in principle but making it work properly can be a real headache.

Pls. provide a few specifics on your application Press. Temp. steam flow, water temp. It may help me or others help you.

 

[pflow]

Here are some parameters:

Superheated steam: 600 degF, 150 psig, 14,000 lb/hr

Saturated Steam: 150 psig

Looking for a method, calculation, or basis for the vessel dimensions.

 

[danberry]

With the sparger system you will not have 150 PSI at the outlet. The pressure loss in the steam sparger will be significant. Your outlet flow would be around 15500 PPH.

What is the required turndown?

How much superheat can you tolerate?

Where will the water come from?

 

[pflow]

turndown = 14:1

max superheat = 2 degF

Water is condensate @ 150 deg.

 

[quark]

2 deg.F is too tight.

Why do you want to go for a vessel? You will have an extra steam flow rate of 1680lb/hr (or 12% of original flowrate). Just check whether your existing piping can take care of this.

 

[danberry]

OK Pflow, A water bath type desuperheater is the right way to go for your operating conditions. I would recommend you purshase a complete skid-mounted unit from an experienced manufacturer instead of trying to make one from scratch.

I beleive Samson and Gestro are two such manufacturers. just google them. They are in Germany but you can probably find something closer to home, wherever that is.

good luck