3 replies to this topic

[Preng]

Hello,

I'm new to this website and I have a question concerning the design of a new vacuum condenser. 

 

Due to space limitations a we need a vertical condenser.

In one of the operating cases the purpose is to condense glycerol out of a stream with mainly glycerol, water and Nitrogen (tubeside of the condenser). Gycerol is going to a reactor, and the water will be condensed in a second condenser before going to a vessel, connected to the vacuum pumps. 

 

Our client does not want a separation vessel between the first and second condenser but wants the separation of condensed glycerol and water+nitrogen to happen in the Heat Exchanger. (Separation does not need to be very effective, entrainment of Glycerol is not a problem)

 

Has anyone already seen such design with a vertical condenser having two outlet nozzles on the bottom head, one for liquid and the other for gas? (I assume a single pass condenser)

Is this something that can be done using HTRI?

I'm new to this software and dit not see any option to do such design with a separation of liquid and gas. 

 

Thanks

[srfish]

There are several designs for the bottom head of a vertical tube-side condenser where the condensate flows downward.  The more common design has a slanted baffle plate just above the vapor outlet on the side. This makes the vapor make a U-turn to an outlet nozzle. The liquid condensate flows past the lower edge of the baffle and continues downward to an outlet nozzle on the bottom.

[Art Montemayor]

Preng:

 

Srfish has given you the precise and accurate answer that is typical of his valued comments on our Forums.  He has probably already designed and built a variety of these.  I have designed and built 2 units - one for process fluids and another for refrigeration condensation purposes.

 

I am attaching a sketch on an Excel workbook for your review as to how I did it with resultant success and perhaps you can get the idea.  The main concept is to focus on making it as feasible for the uncondensed vapor to disengage from the vertically falling liquefied fluid and migrate out through the top side vent nozzle without causing any entrainment of the falling liquid.  To carry out this concept, I always tried to minimize the non-condensed vapor velocity as much as practically possible.  It is advisable to segregate the condensed liquid from the non-condensed vapor as far down stream as you can, in a natural laminar velocity without causing turbulence and the associated entrainment that accompanies it.  Of course, the higher the top outlet vent is located above the condensed liquid level, the better the separation.  This increased height in the condenser is a tradeoff that you must pay for incorporating the required separation step into the liquid sump of the condenser.  I used a demister mesh pad in one application and the first one I built had no demister mesh pad.  Both worked satisfactorily well without entrainment.  However, the applications were different in nature and capacities.

Attached Files

•  Vertical Condenser Venting.xlsx   16.99KB   420 downloads

[Preng]

Thanks a lot.