Closed zasddsgg closed 11 months ago
zasddsgg
commented
1 year ago It seems to be the error caused by the activity coefficient of 0. I tried to change the operating conditions of Flash, such as setting "V=0.02, P=101000", "Q=0, P=101000", but the above error was still reported.
zasddsgg
commented
1 year ago Hello, I tried different conditions for solving the above error, but error was still reported under the conditions I set. If I remove phenol from the feed stream, then no error was reported. But actually, phenol is in my system. It is a little strange. If I do not remove phenol, execute feed.vle(T=180+273.15, P=101000) instead of F101 = units.Flash('F101', feed, outs=('vapor', 'liquid'), T=180+273.15, P=101000), there was no error, which was strange. Isn't Flash() the same as Stream.vle()? Why does one report an error and the other not? Does Stream.vle() and Flash(), set the same parameters, such as V,P or T,P or V,T, return the same result? Thanks for your help. Wish you a good day.
zasddsgg
commented
12 months ago Hello, I still haven't solved the above error, could you please have a look at it when you are free. Thanks for your help. Wish you a good day.
yalinli2
commented
11 months ago from what I can tell the problem is not in the stream's vle, it's in the heat exchanger of the Flash, the F101 = units.Flash('F101', feed, outs=('vapor', 'liquid'), Q=0, P=101000) could work, but I'm not sure if it makes any sense for your system.
also, removing phenol from the system won't solve the problem for me (i.e., the following code still trigger the error):
import biosteam as bst
from biosteam import settings
from biosteam import units
Riboflavin = bst.Chemical('Riboflavin', Hf=-55700, Tc=650+273.15, Tb=240+273.15, Hvap=63457)
Ethanol = bst.Chemical('Ethanol')
Water = bst.Chemical('Water')
carbon = bst.Chemical('carbon')
phenol = bst.Chemical('phenol')
bst.settings.set_thermo([Riboflavin, Ethanol, Water, carbon, phenol])
feed = bst.Stream(
ID='feed',
price=0.0816,
units='kg/hr',
Water=22,
Ethanol=788,
carbon=50,
Riboflavin=30,
# phenol=30,
T=300+273.15,
P=7500000,
)
F101 = units.Flash('F101', feed, outs=('vapor', 'liquid'), T=180+273.15, P=7500000) Thanks for your reply, I tried using F101 = units.Flash('F101', feed, outs=('vapor', 'liquid'), Q=0, P=101000), but the following error was still triggered. Moreover, the conditions for Flash in the process is actually T=180+273.15, P=101000. May I ask you how can solve errors in the case T=180+273.15, P=101000 and Q=0, P=101000?
Thanks for your help. Wish you a good day.
The error using F101 = units.Flash('F101', feed, outs=('vapor', 'liquid'), Q=0, P=101000) is as follows:
FloatingPointError Traceback (most recent call last)
File D:\anaconda\envs\zddd\lib\site-packages\thermosteam\equilibrium\dew_point.py:32, in x_iter(x, x_gamma, T, P, f_gamma, gamma_args)
31 try:
---> 32 x = x_gamma / denominator
33 except:
FloatingPointError: divide by zero encountered in divide
During handling of the above exception, another exception occurred:
Exception Traceback (most recent call last)
Cell In[1], line 28
26 F101 = units.Flash('F101', feed, outs=('vapor', 'liquid'), Q=0, P=101000)
27 # if use feed.vle(T=180+273.15, P=101000) instead of Flash, no error occurred
---> 28 F101.simulate()
File D:\anaconda\envs\zddd\lib\site-packages\biosteam\_unit.py:1731, in Unit.simulate(self, run, design_kwargs, cost_kwargs)
1729 for ps in self._specifications: ps.compile_path(self)
1730 self._load_stream_links()
-> 1731 self.run()
1732 self._summary(design_kwargs, cost_kwargs)
File D:\anaconda\envs\zddd\lib\site-packages\biosteam\_unit.py:1392, in Unit.run(self)
1390 if self.run_after_specifications: self._run()
1391 else:
-> 1392 self._run()
File D:\anaconda\envs\zddd\lib\site-packages\biosteam\units\_flash.py:267, in Flash._run(self)
266 def _run(self):
--> 267 separations.vle(self.ins[0], *self.outs, self.T, self.P, self.V,
268 self.Q, self.x, self.y, self._multi_stream)
File D:\anaconda\envs\zddd\lib\site-packages\thermosteam\separations.py:727, in vle(feed, vap, liq, T, P, V, Q, x, y, multi_stream)
725 ms = feed.copy()
726 H = feed.H + Q if Q is not None else None
--> 727 ms.vle(P=P, H=H, T=T, V=V, x=x, y=y)
729 # Set Values
730 vap.phase = 'g'
File D:\anaconda\envs\zddd\lib\site-packages\thermosteam\equilibrium\vle.py:377, in VLE.__call__(self, T, P, V, H, S, x, y)
375 elif H_spec:
376 try:
--> 377 self.set_PH(P, H, stacklevel=1)
378 except NoEquilibrium:
379 thermal_condition = self._thermal_condition
File D:\anaconda\envs\zddd\lib\site-packages\thermosteam\equilibrium\vle.py:1067, in VLE.set_PH(self, P, H, stacklevel)
1064 return
1066 # Check if super heated vapor
-> 1067 T_dew, x_dew = self._dew_point.solve_Tx(self._z, P)
1068 if T_dew <= T_bubble:
1069 T_dew, T_bubble = T_bubble, T_dew
File D:\anaconda\envs\zddd\lib\site-packages\thermosteam\equilibrium\dew_point.py:228, in DewPoint.solve_Tx(self, z, P)
226 args = (P, z_norm, zP, x)
227 try:
--> 228 T = flx.aitken_secant(f, T_guess, T_guess + 1e-3,
229 self.T_tol, 5e-12, args,
230 checkiter=False)
231 except RuntimeError:
232 Tmin = self.Tmin
File D:\anaconda\envs\zddd\lib\site-packages\flexsolve\open_solvers.py:68, in aitken_secant(f, x0, x1, xtol, ytol, args, maxiter, checkroot, checkiter)
66 dx = -2 * xtol
67 abs_ = abs
---> 68 y0 = f(x0, *args)
69 if abs_(y0) < ytol: return x0
70 aitken_iter = utils.scalar_aitken_iter
File D:\anaconda\envs\zddd\lib\site-packages\thermosteam\equilibrium\dew_point.py:138, in DewPoint._T_error(self, T, P, z_norm, zP, x)
136 pcf = self.pcf(T, P, Psats)
137 x_gamma = phi * zP / Psats / pcf
--> 138 x[:] = self._solve_x(x_gamma, T, P, x)
139 return 1 - x.sum()
File D:\anaconda\envs\zddd\lib\site-packages\thermosteam\equilibrium\dew_point.py:129, in DewPoint._solve_x(self, x_gamma, T, P, x)
127 def _solve_x(self, x_gamma, T, P, x):
128 gamma = self.gamma
--> 129 return solve_x(x, x_gamma, T, P, gamma.f, gamma.args)
File D:\anaconda\envs\zddd\lib\site-packages\thermosteam\equilibrium\dew_point.py:45, in solve_x(x_guess, x_gamma, T, P, f_gamma, gamma_args)
43 def solve_x(x_guess, x_gamma, T, P, f_gamma, gamma_args):
44 args = (x_gamma, T, P, f_gamma, gamma_args)
---> 45 x = flx.wegstein(x_iter, x_guess, 1e-10, args=args, checkiter=False,
46 checkconvergence=False, convergenceiter=3)
47 return x
File D:\anaconda\envs\zddd\lib\site-packages\flexsolve\iterative_solvers.py:58, in wegstein(f, x, xtol, args, maxiter, checkiter, checkconvergence, convergenceiter)
56 errors = np.zeros(convergenceiter)
57 x0 = x
---> 58 x1 = g0 = f(x0, *args)
59 wegstein_iter = utils.wegstein_iter
60 fixedpoint_converged = utils.fixedpoint_converged
File D:\anaconda\envs\zddd\lib\site-packages\thermosteam\equilibrium\dew_point.py:34, in x_iter(x, x_gamma, T, P, f_gamma, gamma_args)
32 x = x_gamma / denominator
33 except:
---> 34 raise Exception('liquid phase composition is infeasible')
35 if (x < 0).any():
36 raise Exception('liquid phase composition is infeasible')
Exception: liquid phase composition is infeasibleI'm not sure of your environment, but using the master branch of biosteam/thermosteam, if I run
import biosteam as bst
from biosteam import settings
from biosteam import units
Riboflavin = bst.Chemical('Riboflavin', Hf=-55700, Tc=650+273.15, Tb=240+273.15, Hvap=63457)
Ethanol = bst.Chemical('Ethanol')
Water = bst.Chemical('Water')
carbon = bst.Chemical('carbon')
phenol = bst.Chemical('phenol')
bst.settings.set_thermo([Riboflavin, Ethanol, Water, carbon, phenol])
feed = bst.Stream(
ID='feed',
price=0.0816,
units='kg/hr',
Water=22,
Ethanol=788,
carbon=50,
Riboflavin=30,
phenol=30,
T=300+273.15,
P=7500000,
)
F101 = units.Flash('F101', feed, outs=('vapor', 'liquid'), Q=0, P=101000)
# if use feed.vle(T=180+273.15, P=101000) instead of Flash, no error occurred
F101.simulate()
F101.show()I get
Flash: F101
ins...
[0] feed
phase: 'l', T: 573.15 K, P: 7.5e+06 Pa
flow (kmol/hr): Riboflavin 0.0797
Ethanol 17.1
Water 1.22
carbon 4.16
phenol 0.319
outs...
[0] vapor
phase: 'g', T: 1431.7 K, P: 101000 Pa
flow (kmol/hr): Riboflavin 0.0797
Ethanol 17.1
Water 1.22
carbon 4.16
phenol 0.319
[1] liquid
phase: 'l', T: 1431.7 K, P: 101000 Pa
flow: 0The script run, but design-wise I'm not sure if it makes a lot of sense. You have that carbon chemical with no designation of properties, which could cause problems in simulation.
Also, biosteam's default heating agents are all steams and their temperature limits are not that high, won't be sufficient for your feed stream that's at 573.15 K:
>>> bst.HeatUtility.heating_agents
[<UtilityAgent: low_pressure_steam>,
<UtilityAgent: medium_pressure_steam>,
<UtilityAgent: high_pressure_steam>]
>>> for i in bst.HeatUtility.heating_agents: print(i.T)
412.189
454.77
508.991If you take out that carbon chemical and adjust down your feed temperature, you'll get more reasonable results:
import biosteam as bst
from biosteam import settings
from biosteam import units
Riboflavin = bst.Chemical('Riboflavin', Hf=-55700, Tc=650+273.15, Tb=240+273.15, Hvap=63457)
Ethanol = bst.Chemical('Ethanol')
Water = bst.Chemical('Water')
carbon = bst.Chemical('carbon')
phenol = bst.Chemical('phenol')
bst.settings.set_thermo([Riboflavin, Ethanol, Water, carbon, phenol])
feed = bst.Stream(
ID='feed',
price=0.0816,
units='kg/hr',
Water=22,
Ethanol=788,
# carbon=50,
Riboflavin=30,
phenol=30,
T=220+273.15,
P=7500000,
)
F101 = units.Flash('F101', feed, outs=('vapor', 'liquid'), T=180+273.15, P=101000)
# if use feed.vle(T=180+273.15, P=101000) instead of Flash, no error occurred
F101.simulate()
F101.show()Flash: F101
ins...
[0] feed
phase: 'l', T: 493.15 K, P: 7.5e+06 Pa
flow (kmol/hr): Riboflavin 0.0797
Ethanol 17.1
Water 1.22
phenol 0.319
outs...
[0] vapor
phase: 'g', T: 453.15 K, P: 101000 Pa
flow (kmol/hr): Riboflavin 0.0797
Ethanol 17.1
Water 1.22
phenol 0.319
[1] liquid
phase: 'l', T: 453.15 K, P: 101000 Pa
flow: 0But if your feed is indeed at that high temperature, you'll want to add heating agent that can transfer heat at higher temperature
yoelcortes
commented
11 months ago @yalinli2, @zasddsgg thanks for doing detective work to characterize the error! I was able to figure out the following workaround thanks to it!
I'm not sure what models are in carbon but I don't think it makes sense for it to be in liquid or vapor states. Based on the discussion, we know it is messing up your VLE. If you force it to be a solid only (and therefore not participate in phase equilibrium), then the problem is resolved.
import biosteam as bst
from biosteam import settings
from biosteam import units
Riboflavin = bst.Chemical('Riboflavin', Hf=-55700, Tc=650+273.15, Tb=240+273.15, Hvap=63457)
Ethanol = bst.Chemical('Ethanol')
Water = bst.Chemical('Water')
carbon = bst.Chemical('carbon', phase='s') # !!! Make sure carbon does not participate in VLE
phenol = bst.Chemical('phenol')
bst.settings.set_thermo([Riboflavin, Ethanol, Water, carbon, phenol])
feed = bst.Stream(
ID='feed',
price=0.0816,
units='kg/hr',
Water=22,
Ethanol=788,
carbon=50,
Riboflavin=30,
phenol=30,
T=300+273.15,
P=7500000,
)
F101 = units.Flash('F101', feed, outs=('vapor', 'liquid'), T=180+273.15, P=101000)
F101.simulate()
Hello, when I called Flash, I encountered the following error, which seems to be caused by denominator being zero. I read the thermosteam.equilibrium.dew_point source code at https://biosteam.readthedocs.io/en/latest/_modules/thermosteam/equilibrium/dew_point.html#:~:text=gamma%20%3D%20f_gamma(x%2C%20T%2C%20*gamma_args)%0A%20%20%20%20denominator%20%3D%20gamma. I found denominator, i.e. gamma, but has not yet found a description of f_gamma. So I don't know how to solve this error. Could I trouble you help to have a look this error? Thanks for your help. Wish you a good day.
Strangely enough, when I execute code "feed.vle(T=180+273.15, P=101000)" instead of Flash, no error is reported.
The code is as follows:
The error information is as follows: