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

Revision as of 11:17, 7 November 2011

Twu, Sim and Tassone presented a cubic equation of state for accurate representation of hydrocarbons that has become known as the Twu-Sim-Tassone or TST equation of state^[1]. With a critical compressibility factor of (Eq. 5)

Z_{c} = \frac{p_{c} v_{c}}{R T_{c}} = 0.296296

it better represents the compressibility than many of than the Redlich-Kwong equation of states, including the Soave modified version, and the Peng and Robinson equation of state.

The equation follows the general cubic form resulting in the equation (Eq. 2):

p = \frac{R T}{V_{m} - b} - \frac{a}{(V_{m} - 0.5 b) (V_{m} + 3 b)}

Where $V_{m}$ 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 $T_{c}$ and $P_{c}$ in the forms (Eqs. 3 and 4):

a_{c} = 0.470507 \frac{R^{2} T_{c}^{2}}{P_{c}}

b_{c} = 0.0740740 \frac{R T_{c}}{P_{c}}

References

↑ Chorng H. Twu, Wayne D. Sim and Vince Tassone "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)

Related reading

Chorng H. Twu, Wayne D. Sim and Vince Tassone "Getting a Handle on Advanced Cubic Equation of State", Chemical Engineering Progress November pp. 58-65 (2002)

[1] Chorng H. Twu, Wayne D. Sim and Vince Tassone "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)

[1]

@@ Line 1: / Line 1: @@
-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'''<ref>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)</ref>.  With a critical compressibility factor <math>Z_c</math> 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<ref>Twu, C.H., Sim, W.D., Tassone, V. "Getting a Handle on Advanced Cubic Equation of State." ''Measurement & Control'', pp. 58-65, (2002).</ref>.
+Twu, Sim and Tassone presented a cubic [[Equations of state|equation of state]] for accurate representation of hydrocarbons that has become known as the '''Twu-Sim-Tassone''' or '''TST equation of state'''<ref>[http://dx.doi.org/10.1016/S0378-3812(01)00663-X Chorng H. Twu, Wayne D. Sim and Vince Tassone "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)]</ref>.  With a critical [[compressibility factor]] of (Eq. 5)
-The equation follows the general cubic form resulting in the equation:
+:<math>Z_c = \frac{p_cv_c}{RT_c} =   0.296296  </math>
+it better represents  the compressibility than many of than the [[Redlich-Kwong equation of state]]s, including the Soave modified version, and the [[Peng and Robinson equation of state]].
+The equation follows the general cubic form resulting in the equation (Eq. 2):
 :<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]].  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:
+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 (Eqs. 3 and 4):
-:<math>a=\frac{0.427481R^2T_c^2}{P_c}</math>
+:<math>a_c=0.470507   \frac{ R^2T_c^2}{P_c}</math>
-:<math>b=\frac{0.086641RT_c}{P_c}</math>
+:<math>b_c=0.0740740  \frac{ RT_c}{P_c}</math>
 ==References==
 <references/>
+;Related reading
+*[http://www.aiche.org/uploadedFiles/CEP/Issues/110258.pdf Chorng H. Twu, Wayne D. Sim and Vince Tassone "Getting a Handle on Advanced Cubic Equation of State", Chemical Engineering Progress '''November''' pp. 58-65 (2002)]
 [[category: equations of state]]

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

Revision as of 11:17, 7 November 2011

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