De-bottlenecking with sub-cooler?

HI,

We currently have a large refrigeration unit for a chemical proces. It consists of 2 compressors a condensor with receiver. The refrigerant(R22) is pumped to an expander and flashvessel.
The refrigerant flashes for a large portion immediately in the flasvessel(-30C), because of the high temperature of the liquid refrigerant(40C).
The flashvessel is not big enough, because liquid droplets are carried to the compressor(BAD).

Is refrigerant sub cooling a good solution for this problem?
Are there package units to perform this sub cooling?

Thanks !
Michiel

If you contact Wijbenga for this, they will have anyway a solution for you. µ
There must be something wrong inside the flashvessel - I think - or not correct sized.

Hi mcs,
is the vessel open or closed flash. Are your level controls working correctly, or could you have oil floating on the R22 affecting the levl contol.

Kind Regards. Andy. :)

Thanks for all replies!

The chemical reaction and flows, which are cooled, have been increased over the last 20 years.
The flash vessel is definitely too small for the current load.
I figured that 2 things could be done:
1. Increase the size of the flash vessel.
2. Install sub cooling to decrease vapour/liquid load of the flash vessel and increase energy efficiency.

Is there something like a package unit to sub cool the refrigerant ?

Andy: I'm not sure what you mean by an open or closed flash vessel. The level controls work correctly, but the vapour load is just too high for the flashvessel size.

Hi mcs :)
when a flash vessel is used as an interstage cooling vessel for liquid (higher evaporation used to sub cool the liquid, equvalent to the interstage of a recip compressor or the point where a low stage compressor discharges it's gas to be cooled before being taken on to the high stage compressor.).
The vessel may have a coil in which the liquid of the condenser is coiled indirectly, closed flash or no coil, the liquid is expanded to the interstage pressure and the resultant flash gas removed by the high stage suction.
You are probably using the flash vessel as a suction vessel at the low stage, with a level of liquid present to cool the highly superheated suction gases returning from some high temperature (relative) heat load.

Kind Regards. Andy. :)

Hi mcs :)

No coil is open flash

A coil, is colsed flash.

Sorry about the way I posted above, less haste more speed. :D

Kind Regards. Andy. :)

Thanks Andy, that is clear. We have a open flash vessel.

Is a package unit on the market to sub cool the refrigerant ?

Michiel

Hi mcs :)
most industrial plant are bespoke, designed for that purpose. The same with your subcooler. But any decent refrigeration contractor could knock you up a plant to suit, what it would be is dependant on the size of your plant, anthing from a condensing unit with a plate evapotaor, to a stand alone compressor and evaporator.
I would caution using subcooling alone to cure your problem, subcooling will not alway be available on plant start up. Better to increase the vessel size to suit and probably more cost effective.

Kind Regards. Andy. :)