7 replies to this topic

[Hazem Hawwash]

Hi All,

 

I am currently attempting to design a condenser for a methanol-water distillation column. I am currently lost as to how to design the condenser. Do I treat it as a heat exchanger? 

 

Thanks

[Bobby Strain]

It can be an air cooler or shell & tube heat exchanger. Your choice.

 

Bobby

[Hazem Hawwash]

Im planning to design it as a shell and tube. Do I need to take into account any special considerations, as its a condenser, or do I proceed as if it was a shell and tube heat exchanger? Much appreciated.

Edited by Hazem Hawwash, 04 August 2016 - 07:03 PM.

[breizh]

Hazem ,

 

You should consider any textbook on Heat tranfer to support your work .  Let say Process heat transfer by D.KERN .

 

Don't forget the search engine in this forum .

 

Good luck

 

Breizh

Edited by breizh, 08 August 2016 - 02:39 AM.

[prakash23]

Since it is distillation column condenser,you should design the condenser in two parts. First condenser ( meaning condensed liquid mixture at condensing temperature) for returning reflux to the column and rest subcooler at desired temperature ( for storage or as a feed to other process).D.Kern has elaborate procedure for both.

[Art Montemayor]

Hazem:

 

In process designing a condenser, there are some basic design considerations and characteristics that you must take into consideration - not only to meet process specifications, but also to comply with mechanical needs.

 

Because there is fundamentally a change of phase taking place in the heat exchanger due to the removal of latent heat, you have a requirement to isolate the liquid product from any non-condensables in the feed vapor.  In the real life applications there is seldom any exceptions to this because there is almost always some non-condensable gas(es) mixed in with your feed vapor.  That means you must allow for separating the non-condensables and either venting them or removing them from the condenser as they accumulate.  Otherwise, your condensing operation will come to a complete halt due to insulation blanketing due to the accumulation of non-condensables.  This is a mechanical design requirement necessitated by process characteristics.

 

Additionally, you should provide for mechanically draining the produced liquid in an efficient and continuous manner.  Many operators prefer to slightly slope their shell and tube condensers in order to facilitate positive liquid drainage.  This assumes that you condense on the shell side - which is normal way to design a condenser when employing a shell and tube arrangement.  As Bobby infers, there are many types and arrangements of process condensers, employing a variety of heat sinks.  Consequently, there is no "standard" way to process design a condenser.  The recommendation to read and study Don Kern's classic text book, "Process Heat Transfer" is a very good one and should be followed in order to gain a correct insight on how the design(s) are carried out.

[gegio1960]

Hazem,

once aknowledged the valuable advices given above, you should also consider the size of your plant.

Different solutions could be envisaged depending on flowrates, compositions, duties, operating T & P....

Good luck!

[Hazem Hawwash]

Thank you all for the resources and advice you have provided, I shall give it a go and see what happens.

 

Kind regards,

 

Hazem Hawwash