Hi,
I'm thinking of getting a Shell and Tube heat exchanger. The goal is to vaporize a liquid recycle fluid (90% ammonia and 10% water) with heated geothermal brine solution through a heat exchanger, and feed the vaporized recycle fluid into steam turbine and generate power.
I have the the following settings:
1.a Hot brine liquid entering inlet @180F and 100 psig
1.b Cold recycle gas mixture entering inlet @80~100F and 200~300 psig.
2. Hot liquid brine can have flowrate upto 20,000 bbl/day.
3. I have full control of the flowrate of the recycle liquid entering the heat exchanger.
4. I do not know the exit temperature of both Shell side and the Tube side because I don't know what's possible.
5. The recycle fluid will have boiling T around 130F.
I want to raise the temperature of the recycle fluid as high as possible, but it will be restricted by the 180F temperature of the geothermal fluid. I don't care about the exit temperature of the geothermal fluid as long as I can heat up the recycle fluid as much as possible.
The readings I've done indicates that 10~15C approach temperature is feasible with good heat exchanger design, but this assumes that there's no phase change. But in my case, I need phase change.
I probably want temperature cross because I want the recycle fluid T as high as possible. The software I have (Promax) has an ability to compute the "effective" approach temperature when there's a cross change, so I'm gonna go off of that.
Question: What's a feasible approach temperature when hot liquid (stays as liquid) is used to vaporize a cold liquid into vapor?
I'm trying to run process simulation scenarios, but I do not know what kind of approach temperature is realistic when vaporization is involved.
Thank you!
Edited by reason991, 29 July 2023 - 11:13 PM.