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Specialty Chemistry Forums => Chemical Engineering Forum => Topic started by: deyouja on July 08, 2009, 10:30:04 AM

Title: Real expansion cooling (
Post by: deyouja on July 08, 2009, 10:30:04 AM

I need to calculate the amount of power needed in a heat exchanger to make up for heat loss due to high pressure gas expanding across a valve at a constant flow rate, and a constant pressure upstream of the valve (p1) and down-stream of the valve (p2), P2 is constant due to a back pressure regulator down stream of the valve.  I am only interested in the heat loss due to the primary expansion (2850 --> 400)  The volumes upstream of the valve and down stream of the valve are not changing as the gas is being fed at a constant rate from an infinite supply source. 

The gas is CO2, p1 =2850 psi, p2 = 400 psi, T1=40C.  I would like to keep the down stream temperature at 25C.     

Title: Re: Real expansion cooling (
Post by: eugenedakin on July 13, 2009, 09:34:50 PM

Hello deyouja,

The forums rules mention that I cannot do the work for you. I can only help you figure out the answer.

Could you provide your initial calculations? I am sure that someone will be able to help steer you in the right direction.

Best wishes, and thanks for your help,

Eugene

Title: Re: Real expansion cooling (
Post by: deyouja on July 14, 2009, 02:45:14 PM

Eugene,
No calculations done yet.  I am looking for an equation that accounts for the heat loss taking place at the throttle point (valve) when the upstream and downstream pressures do not change (constant feed, and a back pressure regulator downstream of the throttle).  Thanks..