5 replies to this topic

[mahesh lade]

plz. tell me that how to design an affective heat exchanger, i want to design shell and tube heat exchanger,so plz. tell me how to calculate no. of tubes,H.T. area , H.T. coeff. etc.

MY email id is maheshlade123@rediffmail.com


Regards,
mahesh lade

[Art Montemayor]

Mahesh:

This is an industrial Professional Forum, so I'll state my response as I would to any other professional.

You need a degree in engineering (Chemical or Mechanical preferably) to begin to understand the factors involved in designing and fabricating a heat exchanger. If you don't have one, give up the idea of doing this.

If you are a professional, degreed engineer then you surely have taken the customary heat transfer courses and studied the required material in university. By now, you should have several text books in your private library - I have 10 to 15 - which you have thoroughly read and know back-to-back. If that is the case, then you already know how to design a heat exchanger. Isn't that so? You certainly aren't going to "learn" how to design a heat exchanger in this forum. You do that in the engineering classroom and studying your textbooks and homework problems. This, I presume, you have already done.

If you have a specific problem in some area of the design, perhaps we can help you out. But teaching you how to design a heat exchanger is a bit far out for any Forum. We are here to discuss specific problems involving engineering solutions. While you can certainly learn from what you read in our Forums, you shouldn't think that we can be a substitute for a university education. You're supposed to have taken care of that already.

While some may consider this response harsh, I simply am responding in a factual, realistic and truthful way hoping to assist you in your problem. I sense your problem is that you are not a professional engineer and that you have not studied heat transfer. If you had done those things, you would have specific areas of concern or question on some details - such as how does one calculate the effective tube wall temperature that is employed in calculating the fluid thermal values? Another question might be: does one rely on a film coefficient and an overall "U" in calculating a submerged steam heating coil?

If you can give us your background and specific needs, perhaps we can lend direct assistance.

[Zauberberg]

Mr Montemayor's reply sounds (maybe) too sharp, but I must say I agree with his approach.

I became a member of this forum very recently, and in such a short time I have seen many questions here (industrial professionals forum), for which I can say that they are well below the common knowledge base of ordinary - not the genious one - chemical engineer. And what to say when such questions are being asked from experienced professionals?

I remember what N. Lieberman has written in one of his books - how process simulation and new technologies throw away engineering fundamentals from education standards of young engineers. Many people start to design equipment and processes without knowing the elementary aspects of their operation. It looks like common knowledge (and common sense) are slowly disappearing from chemical engineering education and practice.

Generally, I am of opinion that stupid questions do not exist. But, it depends who asks the question. If hairdresser or busdriver is asking you how ejectors work, that would be OK. But, when chemical engineer asks how to design HEX, I consider it as total wasting of time - that is something he will never learn, if he does not know the base principles of thermodynamics, pressure drop and industrial heat transfer - after such a long time spent in school.

[mahesh lade]

Dear Montemayor's,

i m chem. engg. graudate, but i am not knowing the stepwise procedure,
plz. help me

Thanks in advance

mahesh

[Art Montemayor]

mahesh:

It is a tragic result if you have been deprived of Ch E courses and instructions on how to design a heat exchanger in your university. This is tragic because you MUST MAKE UP THIS DEFICIENCY AS SOON AS POSSIBLE.

You cannot perform as a professional ChE engineer in the near future without this skill under your belt. Therefore, I strongly recommend you purchase recognized and established text books on the subject. The one I always recommend because it is a classic (the first one) is Donald Kern's "Process Heat Transfer". There, you will find the basic, detailed explanations on how to step-wise design a heat exchanger for a multiple of applications - including worked-out examples by the author. Study and master this text book and you will gain back a lot of the knowledge that you might have been deprived of in your academic studies.

You can also download multiple, free articles on heat transfer from this very site - Cheresources. Additionally, you can also use Google's search engine to download literally tons of articles and various informations on heat transfer. I have furnished an Excel workbook on heat exchangers in one of the Posts in this Forum --- I believe it was last year --- and it describes the various TEMA type of shell & tube exchangers and where to apply them and how. I don't have the time available to do this searching through the Internet for you - but you surely can do it yourself. It is next to impossible to try to teach someone how to process design a heat exchanger on this Forum. We would need all the space and illustrations that Kern's book supplies! You must take a pro-active and resourceful role in filling in this void in your education.

[djack77494]

Mahesh,
The responses you are seeing are the only practical answers to the questions you are posing. You are asking for simple "cookbook" answers to very complex problems. They just don't exist. You must work to obtain and master this knowledge. Presumably, you are not working in a vacuum. Ask your engineer co-workers, explore the software used for these tasks, and read the necessary textbooks. Those are the only methods I know of to move towards mastery of these topics.
Doug