Physics Help Forum Calculating Mixture Critical Temperature and Pressure using Equation of State?
 User Name Remember Me? Password

 Advanced Thermodynamics Advanced Thermodynamics Physics Help Forum

 Aug 7th 2018, 07:21 PM #1 Junior Member   Join Date: Aug 2018 Posts: 1 Calculating Mixture Critical Temperature and Pressure using Equation of State? Hello Everyone, I am trying to calculate critical Temperature and Pressure of binary and ternary mixtures using equation of state. In particular, I am using Peng-Robinson Equation of State. I combined this with Van-der Waals critical criterion to get my result, but am way off experimental data. Vander Waals criteria states: dP/dv = 0 and d2P/dv2=0 My steps: 1. I solve the two partial derivative equations mentioned above to end up with a cubic equation in 'v' (molar volume). Solving this I get the critical molar volume 2. I put this back in either of the partial derivative conditions and calculate Temperature using iteration. 3. Now I know Tc and Vc. I put these values back in the equation of state to get my pressure. Problem: My Tc values are still within range or close to experimental data but the Pc values are way off. Attached Plot: Attached plot is of a binary mixture of methane(C1) and propane(C3). Tc and Pc plots are attached vs mole fraction of C1 Attached Thumbnails
 Sep 18th 2018, 07:23 AM #2 Junior Member     Join Date: Sep 2014 Location: Brasília, DF - Brazil Posts: 23 Can you describe in more details what you did?

 Tags calculating, critical, equation, mixture, pressure, state, temperature

 Thread Tools Display Modes Linear Mode

 Similar Physics Forum Discussions Thread Thread Starter Forum Replies Last Post Geraili Advanced Thermodynamics 3 Oct 17th 2017 03:52 PM Robot_Maker20 Advanced Thermodynamics 0 Oct 1st 2010 01:48 PM empiler1 Advanced Thermodynamics 1 Feb 12th 2010 11:22 AM Fwahm Advanced Thermodynamics 0 Feb 11th 2010 08:17 PM werehk Thermodynamics and Fluid Mechanics 0 Jul 18th 2008 11:04 PM