CO2 injection cooling modeling
CO2 injection cooling modeling
(OP)
Hi everyone, it's been a very long time since I had to use my heat transfer knowledge, and the internet is coming up dry with explaining what is involved in the calculation I'm trying to do.
I work for a plant that produces dry food mix that is mostly flour and sugar, and we cool some of our mixes with direct CO2 injection which is delivered to the bottom of the mixer.
My question is: How do you calculate the amount of heat that CO2 needed to cool?
What I'm looking for is the mass of CO2, can anyone clarify the equations and constants involved in the heat from expansion and sublimation that cool the mix so I can calculate the mass therefrom?
Cheers.
Demian
I work for a plant that produces dry food mix that is mostly flour and sugar, and we cool some of our mixes with direct CO2 injection which is delivered to the bottom of the mixer.
My question is: How do you calculate the amount of heat that CO2 needed to cool?
- The temp of the incoming ingredients and their mass is known.
- The required temp change is known (dT)
- The CO2 comes in as a liquid. I'm assuming that it immediately freezes into dry ice snow?
- How much heat does this expansion/freezing of the CO2 remove from the mix? I'm unable to find a good source for the thermodynamics of this process
- I'm assuming that 246 Btu/lb is the correct heat of sublimation of CO2? (not really trusting the internet for information right now)
What I'm looking for is the mass of CO2, can anyone clarify the equations and constants involved in the heat from expansion and sublimation that cool the mix so I can calculate the mass therefrom?
Cheers.
Demian





RE: CO2 injection cooling modeling
The total amount of energy will be the same if the end points are the same.
So Work with heating the liquid, change of state to gas, and heating the gas.
There are some good sites with thermodyamic calculators on them.
Look for ones that site NIST as the data source like carbon-dioxide-properties.com
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P.E. Metallurgy, Plymouth Tube
RE: CO2 injection cooling modeling
je suis charlie
RE: CO2 injection cooling modeling
RE: CO2 injection cooling modeling
RE: CO2 injection cooling modeling
It could be warmer too. The optimum design would arrange the two streams in counterflow.
je suis charlie
RE: CO2 injection cooling modeling
Agreed, that could be the case also in countercurrent flow. It may be some kind of fluidised bed also.
Dalcazar,
May be this cooler mixer has a temp indicator on exit CO2, so you arent left to guess what this exit gas temp is?
RE: CO2 injection cooling modeling
Thanks everyone.