#!/usr/bin/python3
# -*- coding: utf-8 -*-
r"""Pychemqt, Chemical Engineering Process simulator
Copyright (C) 2009-2025, Juan José Gómez Romera <jjgomera@gmail.com>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>."""
from math import exp
from lib.EoS.Cubic.PR import PR
dat = {
126: (0.8313, -0.5701),
127: (0.7311, 0.3594),
28: (0.6644, 0.2885),
24: (0.6396, 0.4639),
55: (0.7303, 0.3486),
450: (1.0223, 1.7081),
52: (0.7825, 0.1751),
32: (0.7366, 0.0216),
128: (0.8317, -0.0149),
130: (1.0791, -0.5313),
447: (2.1183, -6.6355),
140: (0.8283, 0.1495),
125: (0.9813, 0.9529),
65: (0.6640, 0.2062),
139: (0.9016, -0.2409),
63: (0.7393, 0.2837),
175: (0.9227, 0.1891),
98: (0.3801, 0.2109),
342: (0.7979, 0.4790),
40: (0.6670, 0.4720),
345: (0.7357, 1.8414),
99: (0.5082, 0.5011),
171: (0.7497, 0.2442),
49: (0.6877, 0.3813),
102: (0.5924, -0.1033),
48: (0.4489, 0.3207),
100: (0.6433, 0.4615),
105: (0.5014, 0.3624),
172: (0.7511, 0.1902),
112: (0.6705, 0.4636),
38: (0.6651, 0.4814),
36: (0.6366, 0.5328),
222: (0.6955, 0.2458),
163: (2.4837, -6.5968),
294: (0.7712, 0.6816),
133: (0.6572, 0.3478),
3: (0.5336, 0.2431),
134: (1.2417, 0.1381),
22: (0.4873, 0.4570),
135: (2.2459, -4.9603),
129: (0.6499, 0.4672),
155: (0.8758, 0.4057),
45: (0.8084, 0.3129),
162: (0.7740, 0.3761),
137: (0.6495, 0.3559),
197: (0.4516, 0.3038),
212: (-0.1603, -0.9866),
1: (0.0829, -0.4780),
209: (0.6088, -0.6640),
104: (0.6018, -0.0507),
113: (1.1635, -2.0723),
210: (1.1982, -2.8266),
106: (0.5193, -0.1840),
50: (0.5050, 0.4719),
213: (0.5024, 0.5590),
5: (0.6384, 0.3959),
27: (0.6576, 0.3844),
7: (0.7052, 0.3361),
145: (1.1979, 0.8456),
337: (0.8718, 0.1339),
159: (1.0553, 1.5978),
2: (0.4045, 0.1799),
117: (1.2107, -0.5292),
142: (0.8555, 0.1447),
118: (0.7699, 0.5226),
115: (0.6068, 0.3011),
153: (0.8455, 0.2145),
225: (0.6730, 0.2581),
131: (0.7202, 0.5485),
116: (0.5815, 0.3936),
43: (0.8477, 0.2164),
108: (1.3541, -1.5199),
46: (0.4274, 0.3359),
109: (1.8386, -3.6754),
226: (0.9585, 0.6643),
110: (0.5981, 0.4349),
6: (0.6543, 0.4308),
160: (1.0705, 1.3402),
14: (1.0763, 0.0164),
16: (1.1778, 0.0531),
11: (0.8620, 0.3973),
10: (0.7939, 0.4116),
13: (1.0203, 0.0654),
12: (0.9273, 0.3748),
8: (0.7362, 0.3518),
17: (1.2243, 0.1019),
15: (1.1394, -0.0157),
47: (0.4137, 0.2784),
214: (0.6838, 0.2261),
42: (0.8283, 0.2267),
174: (1.0205, -0.0250),
4: (0.5909, 0.3997),
146: (1.1505, 0.8075),
261: (0.7630, 0.1883),
23: (0.5743, 0.4423),
295: (0.7124, 0.4424),
44: (0.8478, 0.1643),
51: (0.7238, 0.4537),
111: (0.4072, 6.1502),
161: (1.0636, 1.7938),
41: (0.7563, 0.3125),
62: (0.8893, 0.0151)}
[docs]
class PRMelhem(PR):
r"""Peng-Robinson cubic equation of state with a modified dependence of
temperature by Melhem
.. math::
\alpha = \exp\left(m\left(1-T_r\right) +
n \left(1-\sqrt{T_r}\right)^2\right)
where n and m are adjustable parameters compound specific
"""
__title__ = "PR Melhem (1989)"
__status__ = "PRMelhem"
__doi__ = {
"autor": "Melhem, G.A., Saini, R., Goodwin, B.M.",
"title": "A Modified Peng-Robinson Equation of State",
"ref": "Fluid Phase Equilibria 47 (1989) 189-237",
"doi": "10.1016/0378-3812(89)80176-1"},
[docs]
def _alfa(self, cmp, T):
# m,n parameters compound specific
if cmp.id in dat:
m, n = dat[cmp.id]
alfa = exp(m*(1-T/cmp.Tc) + n*(1-(T/cmp.Tc)**0.5)**2) # Eq 1
else:
m, alfa = PR._alfa(self, cmp, T)
return 0, alfa
if __name__ == "__main__":
from lib.mezcla import Mezcla
mix = Mezcla(5, ids=[4], caudalMolar=1, fraccionMolar=[1])
eq = PRMelhem(300, 9.9742e5, mix)
print('%0.0f %0.1f' % (eq.Vg.ccmol, eq.Vl.ccmol))
eq = PRMelhem(300, 42.477e5, mix)
print('%0.1f' % (eq.Vl.ccmol))
