High Temperature Heat Exchanger design problem
High Temperature Heat Exchanger design problem
(OP)
Hi,
I'm a postgraduate student and until now I was working with typical PV and HE. Management from my company wants to design flue gas cooler[water] from 800 celcius to 200 under atm. pressure and water from 25 to 45. More experienced CHE proposed S&T straight tube HE with one expansion joint and baffles. ID is 355mm and tube length 3200mm. I have concern about thermal stresses and thermal cycles. I wouldn't be concerned but he choosed wrong materials and expansion joint. Are my concerns valid? I attached concept pic
Sorry for any grammar mistakes.
Arkusz
I'm a postgraduate student and until now I was working with typical PV and HE. Management from my company wants to design flue gas cooler[water] from 800 celcius to 200 under atm. pressure and water from 25 to 45. More experienced CHE proposed S&T straight tube HE with one expansion joint and baffles. ID is 355mm and tube length 3200mm. I have concern about thermal stresses and thermal cycles. I wouldn't be concerned but he choosed wrong materials and expansion joint. Are my concerns valid? I attached concept pic
Sorry for any grammar mistakes.
Arkusz





RE: High Temperature Heat Exchanger design problem
What did he choose and why do you believe he's wrong? After all you said he's more experienced and you're relatively new (based on saying you're a postgraduate student)? Did you ask him about his choice as a learning opportunity?
25 to 45 what?? degrees Celcius? Still atmospheric? What flow rates? What is the expected heat transfer?
Finally is this a school assignment?
Patricia Lougheed
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RE: High Temperature Heat Exchanger design problem
water: 7800 kg/h
gas: 460 kg/h
It is not a school assignment.
The situation:
He's out of reach for two weeks and time is ticking. I've spoken with material engineer and checked the tables. No heat transfer yet.
Regards,
Arkusz
RE: High Temperature Heat Exchanger design problem
RE: High Temperature Heat Exchanger design problem
RE: High Temperature Heat Exchanger design problem
RE: High Temperature Heat Exchanger design problem
Are you certain the material for the tubes is A-105, or did you mean A-106?
Is the gas on the shellside?
Heat transfer issues aside, I would be nervous about 800 C flue gas in contact with either the ID or the OD of the tubes, regardless of the water temperature. The graphitization threshold for carbon steel is about 427 C, and I suspect your mean wall temperature will be at least that.
Regards,
SNORGY.
RE: High Temperature Heat Exchanger design problem
rmw
RE: High Temperature Heat Exchanger design problem
Gas is in the tubes side A 105 as material, that's the reason I'm worried about. At start-up temperature can reach those 800 deg and that's the temperature they want us to design it.
Arkusz
RE: High Temperature Heat Exchanger design problem