The dilemma regarding critical pressure and critical temperature
Thread Content
Our plant is an LNG liquefaction plant that uses a mixture of five different refrigerants for cooling. I would like to know the properties of these five refrigerants, but I haven’t been able to find any information on them. For example, methane has a critical temperature of -82.6°C and a critical pressure of 4.59 Mpa. So, when the temperature drops below the critical temperature, say to -100°C, what is the minimum liquefaction pressure required at that point? -What about 120℃? -What about 90℃? What are the corresponding liquefaction pressures at those other temperatures? Are there any relevant books, formulas, curves, software, or something of that kind? I want to learn *something about these five types of refrigerants in order to gain a deeper understanding and better control over mixed-refrigeration technology! But I just can’t find the relevant learning methods, so I’m turning to everyone here for help! Thank you!
I’m not sure if you understand what critical pressure means; you can find out by looking up the saturated vapor pressure of methane. When the temperature is below the critical temperature and the pressure is above the saturated vapor pressure, liquefaction occurs. The relevant information is available online, with detailed data in property charts
This post was last edited by sifangok on 2016-12-31 20:50 – saturated pressure at -200 degrees is 0.6 KPa； -At 180 degrees, the saturation pressure is 15 KPa ； -At 150 degrees, the saturation pressure is 260 KPa ； -At 125 degrees, the saturation pressure is 950 KPa ； Check it yourself; this is for methane, and I downloaded the chemical property data manuals from forums for the others