ChE313-Project#1-paper - Dyakiw,Matoian Mitri 1 Background...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Dyakiw,Matoian, Mitri 1 Background : Equations of state are used to describe physical properties for a substance or a mixture of substances, and relate these properties, such as temperature, pressure, and volume, in a particular state. The ideal gas law (PV=nRT) is one of the simplest equations of state. However, it cannot predict the formation of a liquid and becomes less accurate at higher pressures and lower temperatures (Equations n.p.). Cubic equations of state, on the other hand, are more accurate. Such equations are Rhedlich-Kwong, Soave-Redlich-Kwong, and Peng-Robinson. These equations are cubic in volume and have one or more real roots, also known as solutions. If the solution to the equation has one real root, it refers to the volume of a vapor phase and indicates there is no liquid phase present. When the solution to the equation has three real roots, one root indicates a liquid phase and another root indicates that a vapor state is present. Typically, the smallest root indicates a liquid phase and the largest root corresponds to a vapor phase. The Peng-Robinson equations, however, does not necessarily follow this concept that the two phases are coexisting in the data range. “Vapor and liquid phases coexist only at the vapor pressure-above the vapor pressure, the liquid root is most stable-below the vapor pressure, the vapor root is more stable” (Elliott 208). The intermediate root has no real meaning simply because it is considered thermodynamically unstable. The Peng-Robinson equation of state, which was chosen for the calculations, was introduced in 1976 and is successful at deriving vapor pressure values for a pure compound near the critical point. (Equation n.p.) The equation taken from Introductory Chemical Engineering Thermodynamics consists of the following: P= RT ρ - a(T)* ρ 2 (1-b ρ ) (1+2b ρ -b 2 p 2 ) where, V refers to the molar volume of pure oxygen, T to temperature in degree Kelvin, and R is the ideal gas constant.
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern