3 replies to this topic

[BabyKFC]

Hello, I am a student currently designing a shell and tube heat exchanger. The task is to design a heat exchanger to cool a stream from 81.8 to 30 degree celcius using cooling water from 20 to 40 degree celcius. I am currently facing troubles trying to meet the actual/required ratio of 1-1.3, getting ratios of less than 1. I have tried maximising my tube length and using the maximum guessed overall heat coefficient (250-750 W/m2.C) but the highest ratio I have obtained is 0.6. I am unsure of what to change further, please advise me if possible. I have attached the TEMA sheet below.

 TEMA2.pdf   42.57MB   26 downloads 

 TEMA1.pdf   42.67MB   41 downloads

[Pilesar]

The exchanger is undersized. Try a 40 inch shell instead of a 20 inch shell as a starting point. After you get enough surface area, you need more tweaks. The baffles are very close. See how spacing them further out affects results. Try opening the baffle cut also. Confirm no fouling factor is correct. Normally, cooling water fouls over time. Heat exchanger design is an iterative process.

[breizh]

Hi,

Consider the resources attached to support your work.

Good luk

Breizh

Attached Files

•  Shell&tube exchanger design NPTEL.pdf   6.21MB   48 downloads
•  EXXON MOBIL - Heat Transfer & Heat Exchangers.pdf   812.53KB   41 downloads

[shvet1]

1/ Start with auto design mode, then modify the design proposed by software

2/ using cooling water from 20 to 40 degree celcius - Lookslike a mistake. What region is this cooling tower located? 

3/ Most properly designed cooling towers I have encountered had dT = 8-10°C. 20°C looks like an overkill.

Edited by shvet1, 12 June 2024 - 11:14 PM.