STEAM JACKETING FOR HEATING A GAS STREAM

[gelsi]

Hi all
I need design information/criteria for operation in object.
I have following data:
3" line jacketed with 4" tube;
350 kg/h of GAS (similar to air)@ 6barg & 25°C , to be heated to 140°C;
satured STEAM 150°C.

I try with double tube unit with shell condensation, but it's very difficult to develop a calculation sheet from zero.

It would be better a xls file, if there is someone in the web. Help!!!!

P.S. I think the better way to heat a stream is an heater equipment (like S&T), while the jacketing make only mantainement of temperature, what do you think?

 

[gelsi]

here is my simple check file after known Nu, Ud and costant properties

 

[LittleInch]

Are you sure all those fixed numbers are correct?

Looks like in the first metre you have around 2000W/m of heat transfer going on. this looks rather high to me and maybe in theory it is feasible, but in practice not, especially with a residence time of 0.14seconds...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[marty007]

I took a quick look and didn't find anything wrong... I hadn't used an LMTD method for my crude check, which made the difference.

Basically the concept is good. Now you need to verify all of your inputs, and put your appropriate safety factor on it.

You also have to consider the effects of high velocity as pointed out by LittleInch.

Cheers,
Martin