16 replies to this topic

[process16]

hello

i want  to ask you some questions about tubulair heat exchanger ( 2 f fuilds with counter courant)

whene we say Q= mCp( T2 - T1 )

what Cp we should take Cp related with T1 or T2?

2/ whats the simple meaning of DTLM?

3/whats the calorique temperature?

4/ what is the proper transfer coefficient (  Up )??

thank you

 

[gegio1960]

why not a good heat transfer textbook? like the classical kern, or perry.

after that reading, you can make the residual questions in the student section of this site.

good luck!

Edited by gegio1960, 17 March 2015 - 11:34 PM.

[process16]

thank you

i have  an urgently calculation to do , i made a quick view and i guess if someone really  understood heat transfer  , he can give  me  good  answers

thanks again!!

[breizh]

tarek12

Try the search feature in this forum , a lot of materials already posted there.

Note : any heat transfer text book or Google will answer your query.

 

Good luck

 

Breizh

Edited by breizh, 18 March 2015 - 01:42 AM.

[gegio1960]

ok, tarek... trying to help you a little bit more while you follow breizh (and mine) advice....

1) you can take Cp at the average temperature between T1 and T2 (each side)

2) you'll easily find the formula for LMTD on the advised sources

3) for the caloric temp you can read this recent thread 

http://www.cheresour...eat-exchangers/

4) in order to obtain a sound U (overall heat transfer coefficient) you have to consider the nature of your two streams and and a published table of Us... you could start from this point 

http://www.cheresour...heat-exchangers

Good luck... and let us know about your progresses, doubts and results ;-)

[process16]

thank you brotheres;  i will check its, and tell u about my progress

[IGC]

I'm assuming there is no phase change in this heat exchanger?

[process16]

no there is isnt ,  we have  hot oil used to heat crude oil

[gegio1960]

...an interesting piece of information that could help in the estimate of U.

site: refinery or field? hot oil normally not used to heat crude oil in a refinery....

is it a new STHE or an existing one to be verified?

which kind of crude oil? light/heavy? raw/desalted/flashed?...

what about the temperatures and the flowrates of the two fluids?

Edited by gegio1960, 20 March 2015 - 11:57 PM.

[Padmakar Katre]

no there is isnt ,  we have  hot oil used to heat crude oil

 

Hi,

What is your exact intent, you want to just estimate the heat transfer area required to meet the desired duty or have to do detailed calculations? If former is correct, you estimate LMTD, pick the typical U value for this service and estimate area. If you need the detailed calculations then you should get hold of Heat transfer Handbook by Kern or any other Author. Good luck.

[breizh]

http://www.hcheattra....com/tools.html

 

To support your work but you need first to understand the basics about Heat transfer.

 

Good luck.

 

Breizh

[process16]

well i read some files  about heat transfer and  how  to do an exacte calculate

my object is  to do a  calculation to determinate the flow massique of the hot  liquide but  the prob  is  ; the out let temperrature of hote liquide  is  unknown too

here we   are   given :

we  want to heat up the  crude  oil with a specifique gravity of 0.762 from 34°c to 60°C and  i know  also  the flow massique of  the crude oil

the liquide used for heat is an oil

we have just its  density,  the inlet temperature

Edited by tarek12, 01 April 2015 - 07:55 AM.

[process16]

http://www.hcheattra....com/tools.html

 

To support your work but you need first to understand the basics about Heat transfer.

 

Good luck.

 

Breizh

sorry but  iwhene we download files  we need a password!!!

[breizh]

tarek 12

 

No password required !

 

Breizh

[gegio1960]

mmm... it seems a puzzle ;-)

from an "external post", we can also know that the HE is an existing one and the flow of crude oil is 90 m3/h.

maybe in the next posts we will acknowledge the inlet temperature of the hot fluid.,,,

[process16]

tarek 12

 

No password required !

 

Breizh

yes yes  i got  it than you!!!

[process16]

well ,  we  will fix  the flow  massique of teh  hot oil, then  we  will apply Q =mCp (T2-T1)

Q1= Q2 we  will get the out let temperature of the  hot  oil

but in this  case wich Cp of hot oil we  should  take? maybe Cp of inlet temperatur??