2 replies to this topic

[freeman]

Dear All,

 

As we know, there are some rules to use double pipe heat exchanger instead of shell and tube heat exchanger.

 

There is a case that the duty of exchanger is lower than 500 kw and the area required is lower than 300 squered feet. So it's economical to design a double pipe heat exchanger for this application

 

I wish to know, when multitube hairpin heat exchanger is used instead of double pipe.

 

Thank you in advance.

[Art Montemayor]

 

Freeman:

 

I have never heard of any “rules” on using double pipe heat exchangers instead of shell and tube units.

 

You should use a multi-tube hairpin unit if you have the space for it, it suits your application, it is economically attractive, and you can easily maintain it.

 

[freeman]

Dear Mr. Montemeyor,

 

Thank you for your recent reply to my question.

 

Double pipe heat exchangers provide countercurrent flow and should be considered as an alternative to shell and tube exchangers, particularly when there are low flow rates, a large temperature cross, the duty is less than 500 kW, the number of tubes per pass required is less than about 30 (19.05 mm o.d. tubes), and the diameter of shell and tube exchanger is 200 mm or less. Under these conditions a shell and tube exchanger is usually uneconomic because a large number of small diameter shells in series is required to provide adequate velocities and near-countercurrent flow (Heat Exchangers by E.A.D Saunders).

 

what is the priorities of multitube hairpin heat exchanger over double pipe heat exchanger.

 

Thank you again.

 

Freeman