Vapor-liquid equilibrium - Revision history

Priya.bagde123: /* Create your own models file/library file and include them when you want them */

2013-06-18T21:30:21Z

Create your own models file/library file and include them when you want them

← Older revision		Revision as of 21:30, 18 June 2013
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	=== Create your own models file/library file and include them when you want them ===		=== Create your own models file/library file and include them when you want them ===

	<source lang="a4c">REQUIRE ~~"~~atoms.a4l~~"~~;		<source lang=a4c>REQUIRE "atoms.a4l";

	REQUIRE ~~"~~mymodels.a4c~~"~~;		REQUIRE "mymodels.a4c:;
	IMPORT ~~"~~johnpye/extpy/extpy~~"~~;		IMPORT "johnpye/extpy/extpy";
	IMPORT ~~"~~vleplots~~"~~;		IMPORT "vleplots";

	MODEL example101;		MODEL example101;
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	'''This file named mymodels.a4c''' has the model antoine and should be in ascdata (preferably) or share/ascend/models and you can add/edit.		'''This file named mymodels.a4c''' has the model antoine and should be in ascdata (preferably) or share/ascend/models and you can add/edit.

	<source lang="a4c">REQUIRE ~~"~~atoms.a4l~~"~~;		<source lang=a4c>REQUIRE "atoms.a4l";

	MODEL antoine(nc WILL_BE symbol_constant;);		MODEL antoine(nc WILL_BE symbol_constant;);

Priya.bagde123: /* Using the PyGTK interface create Txy and Pxy plots */

2013-06-18T21:22:39Z

Using the PyGTK interface create Txy and Pxy plots

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	=== Using the PyGTK interface create Txy and Pxy plots ===		=== Using the PyGTK interface create Txy and Pxy plots ===

	<source lang="a4c">REQUIRE ~~"~~atoms.a4l~~"~~;		<source lang=a4c>REQUIRE "atoms.a4l";

	IMPORT ~~"~~johnpye/extpy/extpy~~"~~;		IMPORT "johnpye/extpy/extpy";
	IMPORT ~~"~~vleplots~~"~~;		IMPORT "vleplots";

	MODEL antoine(nc WILL_BE symbol_constant;);		MODEL antoine(nc WILL_BE symbol_constant;);

Priya.bagde123: /* Define a MODEL for antoine so you can add more component values */

2013-06-18T21:21:02Z

Define a MODEL for antoine so you can add more component values

← Older revision		Revision as of 21:21, 18 June 2013
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	=== Define a MODEL for antoine so you can add more component values ===		=== Define a MODEL for antoine so you can add more component values ===

	<source lang="a4c">REQUIRE ~~"~~atoms.a4l~~"~~;		<source lang=a4c>REQUIRE "atoms.a4l";

	MODEL antoine(nc WILL_BE symbol_constant;);		MODEL antoine(nc WILL_BE symbol_constant;);

Priya.bagde123: /* Enter Temperature as Degrees C not in Kelvin */

2013-06-18T21:19:47Z

Enter Temperature as Degrees C not in Kelvin

← Older revision		Revision as of 21:19, 18 June 2013
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	=== Enter Temperature as Degrees C not in Kelvin ===		=== Enter Temperature as Degrees C not in Kelvin ===

	<source lang="a4c">REQUIRE ~~"~~atoms.a4l~~"~~;		<source lang=a4c>REQUIRE "atoms.a4l";

	MODEL example101;		MODEL example101;

Priya.bagde123: /* Constants in a METHOD called values */

2013-06-18T21:14:35Z

Constants in a METHOD called values

← Older revision		Revision as of 21:14, 18 June 2013
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	=== Constants in a METHOD called values ===		=== Constants in a METHOD called values ===

	<source lang="a4c">REQUIRE ~~"~~atoms.a4l~~"~~;		<source lang=a4c>REQUIRE "atoms.a4l";

	MODEL example101;		MODEL example101;

Priya.bagde123: /* Using an exponential function, instead of natural log (here's why) */

2013-06-18T21:13:37Z

Using an exponential function, instead of natural log (here's why)

← Older revision		Revision as of 21:13, 18 June 2013
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	=== Using an exponential function, instead of natural log [[VLEWhy#UsingExponential\| (here's why)]]===		=== Using an exponential function, instead of natural log [[VLEWhy#UsingExponential\| (here's why)]]===

	<source lang="a4c">REQUIRE ~~"~~atoms.a4l~~"~~;		<source lang=a4c>REQUIRE "atoms.a4l";

	MODEL example101;		MODEL example101;

Priya.bagde123: /* No Units, All variables declared as Factors */

2013-06-18T21:09:57Z

No Units, All variables declared as Factors

← Older revision		Revision as of 21:09, 18 June 2013
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	\|}		\|}
	=== No Units, All variables declared as Factors ===		=== No Units, All variables declared as Factors ===
	<source lang="a4c">REQUIRE ~~"~~atoms.a4l~~"~~;		<source lang=a4c>REQUIRE "atoms.a4l";

	MODEL example101;		MODEL example101;

Priya.bagde123: /* Defining Units like Pressure and Temperature */

2013-06-18T21:08:02Z

Defining Units like Pressure and Temperature

← Older revision		Revision as of 21:08, 18 June 2013
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	=== Defining Units like Pressure and Temperature ===		=== Defining Units like Pressure and Temperature ===

	<source lang="a4c">REQUIRE ~~"~~atoms.a4l~~"~~;		<source lang=a4c>REQUIRE "atoms.a4l";

	MODEL example101;		MODEL example101;

Jpye at 10:31, 18 June 2013

2013-06-18T10:31:06Z

← Older revision		Revision as of 10:31, 18 June 2013
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	The first stage being all variables defined as a "factor". Variables are later defined as "pressure" or "temperature" and so on. While ASCEND allows the modeler to write without much/any structure,		The first stage being all variables defined as a "factor". Variables are later defined as "pressure" or "temperature" and so on. While ASCEND allows the modeler to write without much/any structure,
	as the models become more complex and as the need for their distribution becomes greater, paying attention to the art of model writing becomes important.Yet, when a new user starts with the ASCEND documentation, it can be difficult to read through the elegant models. Thus, this exercise. Note that the discussion in [[~~Intro_to_ASCEND_~~-~~_thin_walled_tank~~]] details the type of thinking we use here in evolving a model.		as the models become more complex and as the need for their distribution becomes greater, paying attention to the art of model writing becomes important.Yet, when a new user starts with the ASCEND documentation, it can be difficult to read through the elegant models. Thus, this exercise. Note that the discussion in the [[Intro to ASCEND - thin walled tank\|thin-walled tank tutorial]] details the type of thinking we use here in evolving a model.

	The example ends with how ''P-x-y'' or ''T-x-y'' plots can be generated python and the scripts written by [[User:Jpye\|John Pye]]. The page was written by [[User:Kchittur\|Krishnan Chittur]].		The example ends with how ''P-x-y'' or ''T-x-y'' plots can be generated python and the scripts written by [[User:Jpye\|John Pye]]. The page was written by [[User:Kchittur\|Krishnan Chittur]].




	== Question ==		== Question ==

UploadBot: Restored page from Google Cache, uploaded by John Pye

2010-05-13T13:50:16Z

Restored page from Google Cache, uploaded by John Pye

New page

This is an attempt at describing how models can be written for solutions in vapor-liquid equilibrium. The answer is written in stages, to show how a model might reasonably be developed using ASCEND.

The first stage being all variables defined as a "factor". Variables are later defined as "pressure" or "temperature" and so on. While ASCEND allows the modeler to write without much/any structure,
as the models become more complex and as the need for their distribution becomes greater, paying attention to the art of model writing becomes important.Yet, when a new user starts with the ASCEND documentation, it can be difficult to read through the elegant models. Thus, this exercise. Note that the discussion in [[Intro_to_ASCEND_-_thin_walled_tank]] details the type of thinking we use here in evolving a model.

The example ends with how ''P-x-y'' or ''T-x-y'' plots can be generated python and the scripts written by [[User:Jpye|John Pye]]. The page was written by [[User:Kchittur|Krishnan Chittur]].

== Question ==

This is Example 10.1 from the book ''Chemical Engineering Thermodynamics'' by Van Ness and Smith, 7th Edition, page 352. [[Special:BookSources/0073104450|ISBN 0073104450]] (read online with Amazon).

<div style="border:solid 1 pt green">
Binary system acetonitrile(1)/nitromethane(2) conforms closely to Raolt's law. Vapour pressures for the pure species are given by the following [http://antoine.frostburg.edu/chem/senese/101/liquids/faq/antoine-vapor-pressure.shtml Antoine equations]:
:<math>\ln \frac{p_1^{sat}}{1 \mathrm{kPa}} = 14.2724 - \frac{2945.47}{(T/{1^\circ \mathrm C)} + 224.00}</math>

:<math>\ln \frac{p_2^{sat}}{1 \mathrm{kPa}} = 14.2043 - \frac{2972.64}{(T/{1^\circ \mathrm C)} + 209.00}</math>

Problem:
:(a) Prepare a graph showing ''p'' vs ''x''1 and ''p'' vs ''y''1 for a temperature of 75 °C.

:(b) Prepare a graph showing ''T'' vs ''x''1 and ''T'' vs ''y''1 for a pressure of 70 kPa.

== Answer ==
A brief explanation of the variables. ''T'' is the system temperature,
''P'' is the total system pressure,
''x''1,''x''2 are the mole fractions of the two components in the
liquid phase and ''y''1,''y''2 are the mole fractions of the two components
in the vapor phase and <math>P_1^S, P_2^S</math> are the vapor pressures
of components 1 and 2 (which we assume we can predict using
Antoine's equation and <math>A_1, B_1, C_1, A_2, B_2~and~C_2</math> are the
Antoine's coefficients).

The relevant equations are (for a binary system)
:<math>x_1 P_1^S = y_1 P</math>

:<math>x_2 P_2^S = y_2 P</math>

:''x''1 + ''x''2 = 1.0

:''y''1 + ''y''2 = 1.0

:<math>ln(P_1^S) = A_1 - \frac{B_1}{T + C_1}</math>

:<math>ln(P_2^S) = A_2 - \frac{B_2}{T + C_2}</math>

{| class="wikitable"
|-
! Name of Calculation
! What is Known
! What we want to calculate
|-
| Bubble Point Pressure
| ''T'',''x''1
| ''P'',''y''1
|-
| Dew Point Pressure
| ''T'',''y''1
| ''P'',''x''1
|-
| Bubble Point Temperature
| ''P'',''x''1
| ''T'',''y''1
|-
| Dew Point Temperature
| ''P'',''y''1
| ''T'',''x''1
|}
=== No Units, All variables declared as Factors ===
<source lang="a4c">REQUIRE "atoms.a4l";

MODEL example101;

P1S, P2S, P, T, x1, x2, y1, y2 IS_A factor;

ln(P1S) = 14.2724 - 2945.47/(T + 224.0);

ln(P2S) = 14.2043 - 2972.64/(T + 209.0);

x1 + x2 = 1.0;
y1 + y2 = 1.0;

x1*P1S = y1*P;
x2*P2S = y2*P;

METHODS
METHOD parta;
FIX T; FIX x1;

x1 := 0.6;
T := 75.0;
END parta;

METHOD partb;
FIX P; FIX x1;

x1 := 0.1;
P := 70.0;
T := 300.0;

END partb;
METHOD doparta;
RUN ClearAll;

RUN parta;
END doparta;
METHOD dopartb;

RUN ClearAll;
RUN partb;
END dopartb;

END example101;</source>

=== Using an exponential function, instead of natural log [[VLEWhy#UsingExponential| (here's why)]]===

<source lang="a4c">REQUIRE "atoms.a4l";

MODEL example101;

P1S, P2S, P, T, x1, x2, y1, y2 IS_A factor;

P1S = exp(14.2724 - 2945.47/(T + 224.0));

P2S = exp(14.2043 - 2972.64/(T + 209.0));

x1 + x2 = 1.0;
y1 + y2 = 1.0;

x1*P1S = y1*P;
x2*P2S = y2*P;

METHODS
METHOD parta;
FIX T; FIX x1;

x1 := 0.6;
T := 75.0;
END parta;

METHOD partb;
FIX P; FIX x1;

x1 := 0.1;
P := 70.0;
T := 300.0;

END partb;
METHOD doparta;
RUN ClearAll;

RUN parta;
END doparta;
METHOD dopartb;

RUN ClearAll;
RUN partb;
END dopartb;

END example101;</source>

=== Constants in a METHOD called values ===

<source lang="a4c">REQUIRE "atoms.a4l";

MODEL example101;

A1, B1, C1, A2, B2, C2 IS_A factor;

P1S, P2S, P, T, x1, x2, y1, y2 IS_A factor;

ln(P1S) = A1 - B1/(T + C1);

ln(P2S) = A2 - B2/(T + C2);

x1 + x2 = 1.0;
y1 + y2 = 1.0;

x1*P1S = y1*P;
x2*P2S = y2*P;

METHODS
METHOD values;
A1 := 14.2724; B1 := 2945.47; C1 := 224.0;

A2 := 14.2043; B2 := 2972.64; C2 := 209.0;

FIX A1; FIX B1; FIX C1; FIX A2; FIX B2; FIX C2;

END values;
METHOD parta;
FIX T; FIX x1;

x1 := 0.6;
T := 75.0;
END parta;

METHOD partb;
FIX P; FIX x1;

x1 := 0.1;
P := 70.0;
T := 300.0;

END partb;
METHOD doparta;
RUN ClearAll;

RUN values;
RUN parta;
END doparta;

METHOD dopartb;
RUN ClearAll;
RUN values;

RUN partb;
END dopartb;

END example101;</source>

=== Defining Units like Pressure and Temperature ===

<source lang="a4c">REQUIRE "atoms.a4l";

MODEL example101;

A1, B1, C1, A2, B2, C2 IS_A factor;

P1S, P2S, P IS_A pressure;
T IS_A temperature;

x1, x2, y1, y2 IS_A fraction;

P1S/100000.0{Pa} = exp(A1 - B1/(T/1.0{K} - 273.15 + C1));

P2S/100000.0{Pa} = exp(A2 - B2/(T/1.0{K} - 273.15 + C2));

x1 + x2 = 1.0;
y1 + y2 = 1.0;

x1*P1S = y1*P;
x2*P2S = y2*P;

METHODS
METHOD default_self;
END default_self;
METHOD values;

A1 := 14.2724; B1 := 2945.47; C1 := 224.0;

A2 := 14.2043; B2 := 2972.64; C2 := 209.0;

FIX A1; FIX B1; FIX C1; FIX A2; FIX B2; FIX C2;

END values;

METHOD parta;
FIX T; FIX x1;

x1 := 0.6;
T := 348.15 {K};
END parta;

METHOD partb;
FIX P; FIX x1;

x1 := 0.1;
P := 70.0 {kPa};
END partb;

METHOD doparta;
RUN ClearAll;
RUN values;

RUN parta;
END doparta;
METHOD dopartb;

RUN ClearAll;
RUN values;
RUN partb;

END dopartb;

END example101;</source>

=== Enter Temperature as Degrees C not in Kelvin ===

<source lang="a4c">REQUIRE "atoms.a4l";

MODEL example101;

A1, B1, C1, A2, B2, C2 IS_A factor;

P1S, P2S, P IS_A pressure;
T IS_A temperature;

x1, x2, y1, y2 IS_A fraction;
T_degC IS_A factor;

P1S/1000.0{Pa} = exp(A1 - B1/(T/1.0{K} - 273.15 + C1));

P2S/1000.0{Pa} = exp(A2 - B2/(T/1.0{K} - 273.15 + C2));

x1 + x2 = 1.0;
y1 + y2 = 1.0;

x1*P1S = y1*P;
x2*P2S = y2*P;

T_degC = T/1{K} - 273.15;

METHODS

METHOD default_self;
END default_self;
METHOD values;

A1 := 14.2724; B1 := 2945.47; C1 := 224.0;

A2 := 14.2043; B2 := 2972.64; C2 := 209.0;

FIX A1; FIX B1; FIX C1; FIX A2; FIX B2; FIX C2;

END values;

METHOD parta;
FIX T; FIX x1;

x1 := 0.6;
T := 348.15 {K};
END parta;

METHOD partb;
FIX P; FIX x1;

x1 := 0.1;
P := 70.0 {kPa};
END partb;

METHOD doparta;
RUN ClearAll;
RUN values;

RUN parta;
END doparta;
METHOD dopartb;

RUN ClearAll;
RUN values;
RUN partb;

END dopartb;

END example101;</source>

=== Define a MODEL for antoine so you can add more component values ===

<source lang="a4c">REQUIRE "atoms.a4l";

MODEL antoine(nc WILL_BE symbol_constant;);

A, B, C IS_A factor;

SELECT(nc)

CASE 'acetonitrile':A = 14.2724; B = 2945.47; C = 224.070;

CASE 'nitromethane':A = 14.2043; B = 2972.64; C = 209.000;

END SELECT;

END antoine;

MODEL example101;

A1, B1, C1, A2, B2, C2 IS_A factor;

P1S, P2S, P IS_A pressure;
T IS_A temperature;

x1, x2, y1, y2 IS_A fraction;
T_degC IS_A factor;

nc1, nc2 IS_A symbol_constant;

nc1 :== 'acetonitrile';

nc2 :== 'nitromethane';

mync1 IS_A antoine(nc1);
mync2 IS_A antoine(nc2);

A1 = mync1.A;
B1 = mync1.B;

C1 = mync1.C;
A2 = mync2.A;
B2 = mync2.B;

C2 = mync2.C;

P1S/1000.0{Pa} = exp(A1 - B1/(T/1.0{K} - 273.15 + C1));

P2S/1000.0{Pa} = exp(A2 - B2/(T/1.0{K} - 273.15 + C2));

x1 + x2 = 1.0;
y1 + y2 = 1.0;

x1*P1S = y1*P;
x2*P2S = y2*P;

T_degC = T/1{K} - 273.15;

METHODS

METHOD parta;
FIX T; FIX x1;

x1 := 0.6;
T := 348.15 {K};
END parta;

METHOD partb;
FIX P; FIX x1;

x1 := 0.1;
P := 70.0 {kPa};
END partb;

METHOD doparta;
RUN ClearAll;
RUN parta;

END doparta;
METHOD dopartb;
RUN ClearAll;

RUN partb;
END dopartb;

END example101;</source>

=== Using the PyGTK interface create Txy and Pxy plots ===

<source lang="a4c">REQUIRE "atoms.a4l";

IMPORT "johnpye/extpy/extpy";
IMPORT "vleplots";

MODEL antoine(nc WILL_BE symbol_constant;);

A, B, C IS_A factor;

SELECT(nc)

CASE 'acetonitrile':A = 14.2724; B = 2945.47; C = 224.070;

CASE 'nitromethane':A = 14.2043; B = 2972.64; C = 209.000;

END SELECT;

END antoine;

MODEL example101;

A1, B1, C1, A2, B2, C2 IS_A factor;

P1S, P2S, P IS_A pressure;
T IS_A temperature;

x1, x2, y1, y2 IS_A fraction;
T_degC IS_A factor;

TdegC IS_A factor;

nc1, nc2 IS_A symbol_constant;

nc1 :== 'acetonitrile';
nc2 :== 'nitromethane';

mync1 IS_A antoine(nc1);

mync2 IS_A antoine(nc2);

A1 = mync1.A;

B1 = mync1.B;
C1 = mync1.C;
A2 = mync2.A;

B2 = mync2.B;
C2 = mync2.C;

P1S/1000.0{Pa} = exp(A1 - B1/(T/1.0{K} - 273.15 + C1));

P2S/1000.0{Pa} = exp(A2 - B2/(T/1.0{K} - 273.15 + C2));

x1 + x2 = 1.0;
y1 + y2 = 1.0;

x1*P1S = y1*P;
x2*P2S = y2*P;

T_degC = T/1{K} - 273.15;
TdegC = T_degC;

METHODS

METHOD parta;
FIX T; FIX x1;

x1 := 0.6;
T := 348.15 {K};
END parta;

METHOD partb;
FIX P; FIX x1;

x1 := 0.1;
P := 70.0 {kPa};
END partb;

METHOD doparta;
RUN ClearAll;
RUN parta;

END doparta;

METHOD dopartb;
RUN ClearAll;

RUN partb;
END dopartb;

METHOD generatepxyplot;

RUN ClearAll;
RUN parta;
RUN doparta;

EXTERNAL pxyplot(SELF);
END generatepxyplot;

METHOD generatetxyplot;

RUN ClearAll;
RUN partb;
RUN dopartb;

EXTERNAL txyplot(SELF);
END generatetxyplot;

END example101;</source>

The following is the '''Python script''' that should be in ascdata or where ASCEND/pygtk can find it:

'' Script written by John Pye, minor changes by Krishnan Chittur. There are two methods txy and pxyplot ''
{{src|models/kchittur/vleplots.py}}:

<source lang="a4c">import extpy
from pylab import *

from solverreporter import *
def txyplot(self):
browser = extpy.getbrowser()

ioff()
figure()
for P in [70000.0]:

self.P.setRealValue(P)
XX1 = []
TT1 = []

XX2 = []
TT2 = []
for x1 in [0.01,0.05,0.1,0.15,0.2,0.25,0.3,0.35,0.40,0.45,0.50,0.55,0.60,0.65,0.7,0.75,0.8,0.85,0.9,0.95,0.99]:

self.x1.setRealValue(x1)
try:
browser.sim.solve(browser.solver,SimpleSolverReporter(browser,message="P = %f, x1 = %f" % (P,x1)))

XX1.append(float(self.x1))
TT1.append(float(self.TdegC))

XX2.append(float(self.y1))
TT2.append(float(self.TdegC))

except:
browser.reporter.reportError('Failed to solve for x1 = %f' % x1)

continue
plot(XX1,TT1)
plot(XX2,TT2)

hold(1)
ion()
show()

extpy.registermethod(txyplot)

def pxyplot(self):
browser = extpy.getbrowser()

ioff()
figure()
for T in [340]:

self.T.setRealValue(T)
XX1 = []
PP1 = []

XX2 = []
PP2 = []
for x1 in [0.01,0.05,0.1,0.15,0.2,0.25,0.3,0.35,0.40,0.45,0.50,0.55,0.60,0.65,0.7,0.75,0.8,0.85,0.9,0.95,0.99]:

self.x1.setRealValue(x1)
try:
browser.sim.solve(browser.solver,SimpleSolverReporter(browser,message="T = %f, x1 = %f" % (T,x1)))

XX1.append(float(self.x1))
PP1.append(float(self.P))

XX2.append(float(self.y1))
PP2.append(float(self.P))

except:
browser.reporter.reportError('Failed to solve for x1 = %f' % x1)

continue
plot(XX1,PP1)
plot(XX2,PP2)

hold(1)
ion()
show()

extpy.registermethod(pxyplot)</source>

=== Create your own models file/library file and include them when you want them ===

<source lang="a4c">REQUIRE "atoms.a4l";

REQUIRE "mymodels.a4c";
IMPORT "johnpye/extpy/extpy";
IMPORT "vleplots";

MODEL example101;

A1, B1, C1, A2, B2, C2 IS_A factor;

P1S, P2S, P IS_A pressure;
T IS_A temperature;

x1, x2, y1, y2 IS_A fraction;
T_degC IS_A factor;

TdegC IS_A factor;

nc1, nc2 IS_A symbol_constant;

nc1 :== 'acetonitrile';
nc2 :== 'nitromethane';

mync1 IS_A antoine(nc1);

mync2 IS_A antoine(nc2);

A1 = mync1.A;

B1 = mync1.B;
C1 = mync1.C;
A2 = mync2.A;

B2 = mync2.B;
C2 = mync2.C;

P1S/1000.0{Pa} = exp(A1 - B1/(T/1.0{K} - 273.15 + C1));

P2S/1000.0{Pa} = exp(A2 - B2/(T/1.0{K} - 273.15 + C2));

x1 + x2 = 1.0;
y1 + y2 = 1.0;

x1*P1S = y1*P;
x2*P2S = y2*P;

T_degC = T/1{K} - 273.15;
TdegC = T_degC;

METHODS

METHOD parta;
FIX T; FIX x1;

x1 := 0.6;
T := 348.15 {K};
END parta;

METHOD partb;
FIX P; FIX x1;

x1 := 0.1;
P := 70.0 {kPa};
END partb;

METHOD doparta;
RUN ClearAll;
RUN parta;

END doparta;

METHOD dopartb;
RUN ClearAll;

RUN partb;
END dopartb;

METHOD generatepxyplot;

RUN ClearAll;
RUN parta;
RUN doparta;

EXTERNAL pxyplot(SELF);
END generatepxyplot;

METHOD generatetxyplot;

RUN ClearAll;
RUN partb;
RUN dopartb;

EXTERNAL txyplot(SELF);
END generatetxyplot;

END example101;</source>
'''This file named mymodels.a4c''' has the model antoine and should be in ascdata (preferably) or share/ascend/models and you can add/edit.

<source lang="a4c">REQUIRE "atoms.a4l";

MODEL antoine(nc WILL_BE symbol_constant;);

A, B, C IS_A factor;

SELECT(nc)

CASE 'acetonitrile':A = 14.2724; B = 2945.47; C = 224.070;

CASE 'nitromethane':A = 14.2043; B = 2972.64; C = 209.000;

END SELECT;

END antoine;</source>

== Additional Ideas ==
'' Extend this to multiple components (more than 2) and create a 'components file' for antoine coefficients ''</div>

[[Category:Documentation]]
[[Category:Examples]]