Twu-Sim-Tassone equation of state: Difference between revisions

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:<math>p=\frac{RT}{V_m-b}-\frac{a}{(V_m-0.5b)(V_m+3b)}</math>
:<math>p=\frac{RT}{V_m-b}-\frac{a}{(V_m-0.5b)(V_m+3b)}</math>


Where <math>V_m</math> is the molar volume, and <math>a</math> and <math>b</math> are the attractive and repulsive parameters akin to those of the [[Van der Waals equation of state]].
Where <math>V_m</math> is the molar volume, and <math>a</math> and <math>b</math> are the attractive and repulsive parameters akin to those of the [[Van der Waals equation of state]]. Relations exists between <math>a</math> and <math>b</math> and the critical parameters <math>T_c</math> and <math>P_c</math> in the forms:
 
:<math>a=\frac{0.427481R^2T_c^2}{P_c}</math>
:<math>b=\frac{0.086641RT_c}{P_c}</math>


==References==
==References==

Revision as of 03:03, 7 November 2011

Twu, Sim and Tassone presented a cubic equation of state for accurate representation of hydrocarbon that has become known as the Twu-Sim-Tassone or TST equation of state[1]. With a critical compressibility factor Zc of 0.2962, it better represents many the compressibility of than the Redlich-Kwong equation of state, including the Soave modified version, and the Peng and Robinson equation of state. This allows it to better represent long chain hydrocarbons[2].

The equation follows the general cubic form resulting in the equation:

p=RTVm−b−a(Vm−0.5b)(Vm+3b)

Where Vm is the molar volume, and a and b are the attractive and repulsive parameters akin to those of the Van der Waals equation of state. Relations exists between a and b and the critical parameters Tc and Pc in the forms:

a=0.427481R2Tc2Pc
b=0.086641RTcPc

References

  1. ↑ Twu, C.H., et al, "A Versatile Liquid Activity Model for SRK, PR and A New Cubic Equation of State TST." Fluid Phase Equilibria, 194-197, pp. 385-399, (2002)
  2. ↑ Twu, C.H., Sim, W.D., Tassone, V. "Getting a Handle on Advanced Cubic Equation of State." Measurement & Control, pp. 58-65, (2002).
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