6 replies to this topic

[Samir Gupta]

I am planning to put into service a partial condenser for a mixture of Organic vapors (BP of 105 deg C max) and air. The organic vapors are supposed to be condensed and separated.

I had used a S&T HE having 6 meters long tubes. Should we go for such long tubes in case of horizontal partial condensers?

The outlet nozzles for process (Shell side) is on top for air + uncondensed vapor and bottom for condensed organics. Shall we put a vapor liquid separator in the downstream of top nozzle?

Can some body suggest the precautions to be taken while employing a horizontal S&T exchanger for partial condenser service.

Thanks in advance...
Samir

[Art Montemayor]

Samir:

what you present is a very practical and sensible question that is often battered about frequently at a plant-level basis and is often not resolved correctly until a learning curve is achieved in the experience department.

Attached find my response to your questions. Note that you haven't specifically defined the problem with sufficient basic data. However, this is such an important item for a lot of plant engineers who have been in similar situations, I've taken the time to document it as detailed as I could.

I hope this addresses your concerns and helps you out.

 Partial_Condenser.xls   56.5KB   406 downloads

[Samir Gupta]

Dear Mr Montemayor

Many thanks for your advise. I shall take care of the points raised by you. Additionally, the following info supplements my query:

1. Condensed liquid is not to be sub cooled. In stead it is a feed for one of the distillation columns.

2. Shell side flow is up-down and there is 1-pass on the shell side.

3. Coolant is cooling water. There is no steep increase in outlet temperature of cooling water. Delta T is designed at 8 to 10 degree C.

4. There is no temperature cross.

Thanks dear, once again.

Samir

[Krunal Shah]

if the condensing vapor is fed at vacuum than minimize the vacuum as much as possible so that will help you to decrease the lose of your desired organic vapor in non-condensate out let...

[srfish]

Hello,

I echo Art's comment on tube length. I wouldn't use up amd down flow where the shell side baffles would be cut horizontally instead of vertically. This woud create small dams that would hold a condensate level at the top of the baffle cut.

[Elizabeth_I]

Thanks for the info, so interesting;)

[JimQ]

For big condenser, "X" or "J21" shell type possiblely can be consideried due to pressure drop in shell side expecially for vaccum scenario. Changeable baffle distance also may be applicable.

Personal opinion top downstream separator is unnecessary. Condenser normally have big enough vapour space in right pressure drop.

Edited by JimQ, 09 May 2011 - 01:45 AM.