How to calculate the temperature of gaseous ammonia after pressure reduction
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I would like to ask experts: at a certain pressure and temperature, when gaseous ammonia is expanded under reduced pressure, its volume increases and its temperature must decrease. How can experts calculate the temperature of gaseous ammonia after pressure reduction? This post was last edited by zhangyong6404 on 2009-3-30 21:33]
Within the positive Joule-Thomson effect TP region, cooling occurs regardless of the degree of expansion.
I tried it using ASPEN: ammonia at 1 atm and 25 degrees Celsius is fed into the turbine. The outlet pressure of the turbine was set, and a sensitivity analysis was conducted. The results show that for outlet pressures ranging from 0.1 to 0.9 atm, the temperature of the ammonia at the outlet follows the -P-B relationship. I’m not sure if this is correct; I hope everyone can discuss it further. VARY 1 T B1 PARAM PRES ATM C 0.1 -70.635504 0.15 -58.373818 0.2 -47.435215 0.25 -38.713962 0.3 -31.399064 0.35 -24.982021 0.4 -19.239614 0.45 -14.030252 0.5 -9.2540337 0.55 -4.837612 0.6 -0.7253948 0.65 3.12593904 0.7 6.75053502 0.75 10.1762108 0.8 13.4257462 0.85 16.5180923 0.9 19.469198
Gaseous ammonia, when the pressure is reduced under high pressure, should follow the principle of throttling expansion, right? How is the heat absorbed from the surroundings during its throttling expansion calculated?
Please, the teacher on the 4th floor! If I have gaseous ammonia at 2.5 MPa and 80 degrees Celsius, and the pressure of the gaseous ammonia exiting the turbine is 0.45 MPa, please calculate the temperature of the gaseous ammonia at the turbine outlet. Thanks!
Inlet/Outlet Temperature: C 80; Pressure: MPa 2.5; Vapor Fraction: 1; 0.95679329. It is advisable to use theoretical knowledge to analyze the validity and usability of the simulation results
Thanks, teacher upstairs! I hope we can become friends. My email: sdfchfcm@163.com
I would like to ask the friend upstairs for another favor: I have an ammonia separation tower with an operating pressure of 2.5 MPa. The feed rate is 5000 K mol/h; the feed is at its boiling point. The ammonia content in the ammonia solution is 65% (by weight). The ammonia content at the top of the tower is greater than 99%, while it is less than 2% at the bottom of the tower. Could you use the ASPEN software to calculate the number of theoretical plates and the diameter of the tower? Thank you!
Distillation columns for ordinary binary systems are easy to simulate; you can use a simulation software to do it yourself. If you’re not familiar with such software, you can go to the ASPEN technical discussion forum to seek advice from experts
Hello, teacher upstairs! I can’t download the ASPEN software. Moreover, my English is not good since it’s in English; please help!
I did the calculations myself; the tower diameter is about 1400 mm, so the theoretical number of plates is only 4. Isn’t that correct?
A simulation using Aspen was conducted; the minimum theoretical number of plates is 4, while the actual number of plates is 11. The feed temperature is 140 degrees (the exact value is not known); the feed plate is number 5. The temperature at the top of the tower is 83 degrees, and at the bottom of the tower it is 223 degrees. The cooling load at the top of the tower is 6.8 million kcal/h, the heat load of the reboiler at the bottom of the tower is 7.1 million kcal/h, and the reflux rate is 14.7 t/h. The tower diameter is 2.2 meters. I’m not sure if this is correct; I’ve never worked with ammonia-based systems before. Could those who are more experienced advise me on what property measurement methods should be used? This post was last edited by shpsw on 2009-4-13 16:49]
I checked the relevant data; about 65% of ammonia water has a boiling point of around 60–70 degrees at 2.0 MPa. I don’t think the feed temperature should be 140 degrees, right?
Whether it is throttling expansion depends on whether the process is adiabatic. If it is an adiabatic process, it can be calculated according to what the people above said.