Distillation Column Steam Sparger
Distillation Column Steam Sparger
(OP)
Hi,
Because this is my first time sizing a steam sparger, I would like to get some outside inputs to see if I'm going about it correctly.
I am designing a steam sparger to be used in a distillation column operating at 17psia (bottom). The steam sparger will be 8" in diameter with 20 holes (10 on each side). Steam enters the column at 45 psia, 9539 lb/hr. My main difficulty have been sizing the holes. To do this, I used Bernoulli's equation for compressible fluid (P1 = 45psia, P2 = 17 psia + liquid head pressure, Cp/Cv = 1.244). My resulting diameter for each hole is 1.27". Does the hole diameter sound reasonable for the desired pressure drop?
Thank you.
Because this is my first time sizing a steam sparger, I would like to get some outside inputs to see if I'm going about it correctly.
I am designing a steam sparger to be used in a distillation column operating at 17psia (bottom). The steam sparger will be 8" in diameter with 20 holes (10 on each side). Steam enters the column at 45 psia, 9539 lb/hr. My main difficulty have been sizing the holes. To do this, I used Bernoulli's equation for compressible fluid (P1 = 45psia, P2 = 17 psia + liquid head pressure, Cp/Cv = 1.244). My resulting diameter for each hole is 1.27". Does the hole diameter sound reasonable for the desired pressure drop?
Thank you.





RE: Distillation Column Steam Sparger
For choked steam flow I suggest reading thread124-139392: Sizing of orifice?.
If my memory doesn't fail me the Cp/Cv value seems low. Is your sparging submerged in liquid ?
RE: Distillation Column Steam Sparger
I would go for a larger number of smaller holes. With 1.27" (or even 0.6") holes you will get a lot of vibration from cavitation, especially at startup. It would be better to use 0.25" or less, but of course the drilling can become a problem with so many holes.
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Distillation Column Steam Sparger
In what country will this sparger be installed ?
These people have a sparger design guideline:
http
-MJC
RE: Distillation Column Steam Sparger
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Distillation Column Steam Sparger
thread124-144594: Steam Injection Detail
The result was that we bought a set (4) of these
http://www.komax.com/det-shscepter.html
which worked fine. From a cost standpoint there would have been essentually no savings in building a custom sparger.
best wishes,
sshep
RE: Distillation Column Steam Sparger
In regards to 25362 question, the sparger will be submerged in water. I’m currently not sure how much water will be above the sparger but I was guessing about 1 foot.
In regards to MJCronin question, the sparger will be place in a distillation column in Thailand.
RE: Distillation Column Steam Sparger
If you do not have experience with this type of sparger I believe it would be better to go with one of the proprietary types as recommended by sshep. I think Spirax, and probably Armstrong, make them as well. I agree with sshep that any additional cost for the proprietary units is insignificant when looking at the cost of the column as a whole.
I have installed spargers with many more than 100 holes. If you can get them punched or laser cut it is easier and faster than drilling.
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Distillation Column Steam Sparger
Obtain a copy of "Design of Gas Distributors" by W.J. Litz, Tennessee Eastman Co. in the November 13, 1972 edition of Chemical Engineering magazine.
It describes several factors such as how to obtain adequate distribution and avoid sparge plugging in straight-pipe, ring and plate gas distributors/spargers for process vessels.
RE: Distillation Column Steam Sparger
RE: Distillation Column Steam Sparger
According to Mr Henry Z. Kister book Distillation Operation, it is not recommended introducing gas streams in column liquid level, but if it is necessary sparger must be used. Only reason for do this, as I see, is lack of space in column bottom.
I have experience on crude unit, stripping steam for main column and all strippers are introduced by sparger into liquid level. No problems with strippers but for main column (stripping of long residue) we have foam formation due effects of submerged stripping steam. Because of that level control was very difficult, it is possible to control level up to 40%, if level indication go up it was possible to flood all column by residue. Finally we revamped that and put steam sparger in gas phase.
Regards,
Milutin
RE: Distillation Column Steam Sparger
With respect to sparging steam into a mixure, this is for heat input and it is not as important to have the same dispersion as for mass transfer with a gas. The important considerations are hammers (esp start-up), noise, vibrations, etc. I think 45psig steam is more pressure than neccessary, and can only cause problems- better to let the steam down through a valve and reduce the noise at the sparger if you are determined to build one.
best wishes,
sshep