Prashanth:
As a chemical engineering student assigned to submit a design on a chlorine process, you should be prepared to explain and defend what you submit (or recommend). I would not recommend any gasketed joint for a chlorine application unless it was a special, scrutinized, and approved installation. The potential leak of chlorine poses a highly dangerous event for operational personnel and should always be a consideration before using a gasketed joint.
If you have a relatively small chlorine flow stream (as you admit), then use a totally welded, alloy spiral type of heat exchanger. These are available for this type of application; a Graham Heliflow type is just one example. You can also fabricate your own cooler. I've done this before in several applications. Look in Kayode Coker's great book, "Ludwig's Applied Process Design for Chemical and Petrochemical Plants", Volume 3; 4th Edition; Chapter 15, Heat Transfer, for examples and illustrations. You cannot deal with a hazardous chemical like chlorine without taking the proper safety precautions and applying special, safe procedures. Safety with hazardous chemicals is something that has been lacking as an engineering course and study in universities and unfortunately is not addressed until the young engineer is working out in industry and on his/her own learnings.
For an example of the type of exchanger, go to: http://www.cheresour...ger/#entry99562
and download the great heat exchanger manual that our experienced member Breizh has attached. Look in page 8 and you will get a good idea of the type of exchanger that I write about.