4 replies to this topic

[potorozz]

I am a graduate process engineer and I have been assigned a project to design a new vent condenser. I have vent gas from three drums and it is combined to feed the condenser in the tube side with brine as coolant in the shell side.

 

The type of condenser is a BEM (one tube pass).  The condensed liquid will be transferred to a waste drum system and the vent gas is to go to flare.  I found that the existing unit in my plant haa two systems for a condenser loop as seen in the attached file. I am not sure of the advantage and disadvantage of each system.  Could you all share your experience or suggest some guidelines to me?

 

In my opinion, system 1 is better since it can be continuously drained to the waste drum without a need for a level transmitter in seal pot drum.

 

Thank you for your sharing.

 

Potorozz

Attached Files

•  New condenser loop.xlsx   70.18KB   238 downloads

Edited by Art Montemayor, 05 January 2016 - 10:50 AM.
grammar, composition, structure

[srfish]

Both systems are capable. I don't believe the method of removing the vent gas as shown in system 1 is as efficient as that of system 2. The side draw-off method as shown in system 1 depends on only a slanted baffle to do the vapor- liquid separation. The drain pot of system 2 could be designed to have very good vapor- liquid separation.

[Art Montemayor]

Potorozz:

 

How you configure and pipe the vertical condenser has a lot to do with the quantitative perspective as well as the qualitative perspective of the process fluid you are cooling.  What I mean by this is that the proportion of condensate to vent gas is important in designing the layout and the piping.  You haven't given us any basic data other than your concept.

 

The amount of non-condensable vent gas is important in doing the design of the condenser.

 

This subject has been discussed many times in the past in this Forum.  One method is given in the attached workbook.  Note that there is no need for an additional vessel.  The bottom bonnet is designed  in accordance with the flowrates of the condensate and vent gas.

Attached Files

•  Vertical Condenser Venting.xlsx   126.72KB   252 downloads

[Bobby Strain]

Brine coolant? Are you sure? The arrangement will be determined by the flow, pressure, temperature, and composition. I wouldn't normally design the condenser. Instead, develop a specification for vendors to provide quotations. I'm guessing that you don't have software to design it either.

 

Bobby

[shan]

System 2 is better because the Seal Pot has no gas outlet in System 1.  When the carry over vapor and flashed gas are accumulated in the Seal Pot of System 1 to certain extent, the Seal Pot pressure will be balanced between the Seal Pot and Shell Side of Condenser so that condensed liquid is unable to flow into the Seal Pot.