1 reply to this topic

[korf08]

Hello,

For the calculation of demister size we use a value: K value.
For stainless steel demisters this value is 0,107 m/s
For plastic demisters this value is much lower: around 0,06 m/s

1
Why do have a plastic demsiter a lower value?
2
Where are this value based on?
3
Is this value also different for each type of plastic?

we can help me??

[mbeychok]

korf08:

A k value of 0.107 m/s (0.35 ft/sec) is pretty much an industry standard for use with the Souders-Brown equation in sizing mesh pad demisters. I don't know why a plastic mesh pad would use a different K value than a metallic mesh pad.

The GPSA Engineering Data Book recommends the following k values (in ft/s) for vertical drums with horizontal mesh pads (at the denoted operating pressures):

0 psig: 0.35
300 psig: 0.33
600 psig: 0.30
900 psig: 0.27
1500 psig: 0.21

GPSA Notes:
1. K = 0.35 at 100 psig; subtract 0.01 for every 100 psi above 100 psig
2. For glycol or amine solutions, multiply above K values by 0.6 – 0.8.
3. Typically use one-half of the above K values for approximate sizing of vertical separators without mesh pads.
4. For compressor suction scrubbers and expander inlet separators, multiply K by 0.7 – 0.8

I suggest that you contact Koch-OttoYork at www.koch-ottoyork.com for help with your question about plastic demisters.