Questions about units operations

[1226Wang1226]

Q1. System Simulation Issue
I am unable to simulate the entire system (sys.simulate() fails). The problem seems to originate from the absorber and stripper units. However, I am uncertain how to identify or address the specific issues.
Here is the error message:
TypingError Traceback (most recent call last)
Cell In[2], line 79
77 additional_MEA_needed = required_MEA_mass - total_MEA
78 hx4=bst.HXutility('HX4',ins=M1-0,outs=makeup,T=318.15)
---> 79 sys.simulate()
80 sys.diagram(number=True, kind='cluster')

File ~/anaconda3/lib/python3.12/site-packages/biosteam/_system.py:2793, in System.simulate(self, update_configuration, units, design_and_cost, **kwargs)
2773 def simulate(self, update_configuration: Optional[bool]=None, units=None,
2774 design_and_cost=None, **kwargs):
2775 """
2776 If system is dynamic, run the system dynamically. Otherwise, converge
2777 the path of unit operations to steady state. After running/converging
(...)
2791
2792 """
-> 2793 with self.flowsheet:
2794 specifications = self._specifications
2795 if specifications and not self._running_specifications:

File ~/anaconda3/lib/python3.12/site-packages/biosteam/_flowsheet.py:120, in Flowsheet.exit(self, type, exception, traceback)
118 def exit(self, type, exception, traceback):
119 main_flowsheet.set_flowsheet(self._temporary_stack.pop())
--> 120 if exception: raise exception

File ~/anaconda3/lib/python3.12/site-packages/biosteam/_system.py:2849, in System.simulate(self, update_configuration, units, design_and_cost, **kwargs)
2843 outputs = self.simulate(
2844 update_configuration=True,
2845 design_and_cost=design_and_cost,
2846 **kwargs
2847 )
2848 else:
-> 2849 raise error
2850 else:
2851 if (not update_configuration # Avoid infinite loop
2852 and self._connections != [i.get_connection() for i in self.streams]):
2853 # Connections has been updated within simulation.

File ~/anaconda3/lib/python3.12/site-packages/biosteam/_system.py:2837, in System.simulate(self, update_configuration, units, design_and_cost, **kwargs)
2835 try:
2836 outputs = self.converge(**kwargs)
-> 2837 if design_and_cost: self._summary()
2838 except Exception as error:
2839 if update_configuration: raise error # Avoid infinite loop

File ~/anaconda3/lib/python3.12/site-packages/biosteam/_system.py:2550, in System._summary(self)
2548 if i in simulated_units: continue
2549 simulated_units.add(i)
-> 2550 f(i, i._summary)
2551 for i in self._facilities:
2552 if isa(i, Unit): f(i, i.simulate)

File ~/anaconda3/lib/python3.12/site-packages/thermosteam/exceptions.py:94, in try_method_with_object_stamp(object, method, args)
92 raise StampedKeyError(message_with_object_stamp(object, repr(error.args[0])))
93 except Exception as error:
---> 94 raise_error_with_object_stamp(object, error)

File ~/anaconda3/lib/python3.12/site-packages/thermosteam/exceptions.py:84, in raise_error_with_object_stamp(object, error)
82 error.args = (message_with_object_stamp(object, msg), *args)
83 except: pass
---> 84 raise error

File ~/anaconda3/lib/python3.12/site-packages/thermosteam/exceptions.py:88, in try_method_with_object_stamp(object, method, args)
86 def try_method_with_object_stamp(object, method, args=()):
87 try:
---> 88 return method(*args)
89 except StampedKeyError as error:
90 raise StampedKeyError(message_with_object_stamp(object, error.args[0]))

File ~/anaconda3/lib/python3.12/site-packages/biosteam/_system.py:2550, in System._summary(self)
2548 if i in simulated_units: continue
2549 simulated_units.add(i)
-> 2550 f(i, i._summary)
2551 for i in self._facilities:
2552 if isa(i, Unit): f(i, i.simulate)

File ~/anaconda3/lib/python3.12/site-packages/thermosteam/exceptions.py:94, in try_method_with_object_stamp(object, method, args)
92 raise StampedKeyError(message_with_object_stamp(object, repr(error.args[0])))
93 except Exception as error:
---> 94 raise_error_with_object_stamp(object, error)

File ~/anaconda3/lib/python3.12/site-packages/thermosteam/exceptions.py:84, in raise_error_with_object_stamp(object, error)
82 error.args = (message_with_object_stamp(object, msg), *args)
83 except: pass
---> 84 raise error

File ~/anaconda3/lib/python3.12/site-packages/thermosteam/exceptions.py:88, in try_method_with_object_stamp(object, method, args)
86 def try_method_with_object_stamp(object, method, args=()):
87 try:
---> 88 return method(*args)
89 except StampedKeyError as error:
90 raise StampedKeyError(message_with_object_stamp(object, error.args[0]))

File ~/anaconda3/lib/python3.12/site-packages/biosteam/_unit.py:1205, in Unit._summary(self, design_kwargs, cost_kwargs, lca_kwargs)
1203 if not (self._design or self._cost): return
1204 if not self._skip_simulation_when_inlets_are_empty or not all([i.isempty() for i in self._ins]):
-> 1205 self._design(**design_kwargs) if design_kwargs else self._design()
1206 self._cost(**cost_kwargs) if cost_kwargs else self._cost()
1207 self._lca(**lca_kwargs) if lca_kwargs else self._lca()

File ~/anaconda3/lib/python3.12/site-packages/biosteam/units/distillation.py:2300, in AdiabaticMultiStageVLEColumn._design(self)
2298 rho_V = vapor_out.rho
2299 L = liquid_out.F_mass # To get liquid going down
-> 2300 F_LV = design.compute_flow_parameter(L, V, rho_V, rho_L)
2301 C_sbf = design.compute_max_capacity_parameter(TS, F_LV)
2302 sigma = liquid_out.get_property('sigma', 'dyn/cm')

File ~/anaconda3/lib/python3.12/site-packages/numba/core/dispatcher.py:423, in _DispatcherBase._compile_for_args(self, *args, **kws)
419 msg = (f"{str(e).rstrip()} \n\nThis error may have been caused "
420 f"by the following argument(s):\n{args_str}\n")
421 e.patch_message(msg)
--> 423 error_rewrite(e, 'typing')
424 except errors.UnsupportedError as e:
425 # Something unsupported is present in the user code, add help info
426 error_rewrite(e, 'unsupported_error')

File ~/anaconda3/lib/python3.12/site-packages/numba/core/dispatcher.py:364, in _DispatcherBase._compile_for_args..error_rewrite(e, issue_type)
362 raise e
363 else:
--> 364 raise e.with_traceback(None)

TypingError: <System: SYS2> <AdiabaticMultiStageVLEColumn: U105> Failed in nopython mode pipeline (step: nopython frontend)
No implementation of function Function() found for signature:

truediv(none, none)

There are 8 candidate implementations:

• Of which 6 did not match due to:
  Overload of function 'truediv': File: : Line N/A.
  With argument(s): '(none, none)':
  No match.
• Of which 2 did not match due to:
  Operator Overload in function 'truediv': File: unknown: Line unknown.
  With argument(s): '(none, none)':
  No match for registered cases:
  • (int64, int64) -> float64
  • (int64, uint64) -> float64
  • (uint64, int64) -> float64
  • (uint64, uint64) -> float64
  • (float32, float32) -> float32
  • (float64, float64) -> float64
  • (complex64, complex64) -> complex64
  • (complex128, complex128) -> complex128

During: typing of intrinsic-call at /Users/ershi/anaconda3/lib/python3.12/site-packages/biosteam/units/design_tools/column_design.py (309)

File "anaconda3/lib/python3.12/site-packages/biosteam/units/design_tools/column_design.py", line 309:
def compute_flow_parameter(L, V, rho_V, rho_L):

"""
return L/V*(rho_V/rho_L)**0.5
^

Q2. Heat Exchanger Input/Output Issue
the heat exchanger I am using in my model allows only a single inlet and a single outlet. However, I need to modify it so that the heat exchanger can handle two inlets and two outlets.
The current heat exchanger allows only a single inlet and a single outlet, but i need two inlets and two outlets. Just like this:

Q3. Valve not displaying
I added a valve unit to the flowsheet, but it is not showing up in the diagram. Could this be due to a visualization issue?

Here is my code:
ques.txt

Thank you for your help!!

[yoelcortes]

@1226Wang1226,

Happy to help:

1. Valve is an abstract class (not meant for the user). I will plan on changing the name later so others do not get confused. Use IsenthalpicValve instead.
2. Use HXprocess (HXutility exchanges heat with a utility; HXprocess exchanges heat between process streams). This one has two inlets and two outlets.
3. The diagram of the valve seems to be broken (it shows only as box), I will look into it.

By the way, the specification on M1 does not do anything:

    @M1.add_specification(run=True, args=[0.30])
    def adjust_MEA_content(MEA_fraction):
        MEA_in_amine=amine.imass['Monoethanolamine']
        MEA_in_liquid=liquid.imass['Monoethanolamine']
        total_MEA = MEA_in_amine + MEA_in_liquid
        total_in_mass = sum(stream.F_mass for stream in M1.ins)
        required_MEA_mass= MEA_fraction * total_in_mass
        additional_MEA_needed = required_MEA_mass - total_MEA # This variable is not used anywhere! Did you mean to add flow somewhere?

The process is still not converging, but I can have a look at it once you feel it is complete (fixed specification, heat exchanger, etc.).

Thanks,

[1226Wang1226]

@yoelcortes,
Thank you again! And here is my new code:
ques.txt
I fixed M1 specification(i think), and it's still have problem when i simulate😢

[yoelcortes]

@1226Wang1226, thanks for the follow up. There was an error when creating diagrams with process heat exchangers with missing streams (quite an oddly specific error, I know). Please pip install biosteam==2.50.1 and pip install thermoteam==0.50.1 to fix it.

I made minor changes to your code and get the following diagram. I think some streams are not connected well:

import biosteam as bst
bst.main_flowsheet.set_flowsheet('Chemical_scrubbing_biogas')
chemicals = bst.Chemicals(
    ['Water', 'CO2', 'CH4', 'H2S', 'N2', 'O2','Monoethanolamine']
)
bst.settings.set_thermo(chemicals)
bst.settings.mixture.include_excess_energies = True 
raw_biogas=bst.Stream(
'raw_biogas',
CH4=214.84,
CO2=382.8,
H2S=0.228,
N2=3.12,
O2=3.57,
T=298.15,
P=101325,
total_flow=500,
units='kg/hr',
phase='g'
)

amine=bst.Stream('amine',Monoethanolamine=200, units='kmol/hr',phase='l')
gas_rec=bst.Stream('gas_rec',
)
air_in=bst.Stream('air_in',
N2=987.91,
O2=299.96,
units='kg/hr',
phase='g'
)
sol_fl = bst.Stream('sol_fl')
rich_solution = bst.Stream('rich_solution',
CO2=614.26,
CH4=11.29,
H2S=0.27,
N2=0.073,
O2=0.16,
H2O=84365,
units='kg/hr',
phase='l',
P=1e6
)
gas_out=bst.Stream('gas_out')
gas_exit=bst.Stream('gas_exit')
cooledbg=bst.Stream('cooledbg')
gasrec=bst.Stream('gasrec')
makeup=bst.Stream('makeup')
fresh_water=bst.Stream('fresh_water', water=2000, units='kg/hr')
process_water=bst.Stream('process_water')
water_rec=bst.Stream('water_rec', water=82370,units='kg/hr')
water=bst.Stream('water')
liquid=bst.Stream('liquid')
with bst.System() as sys:
    U101 = bst.IsentropicCompressor('U101',raw_biogas, outs='raw_biogas_0',P=150000, eta=0.75)
    hx1=bst.HXutility('HX1', ins=U101-0, outs='raw_biogas_1', T=308.15)
    P1=bst.Pump('P1',ins=makeup,P=150000)
    U102 = bst.Absorber(
        'U104', T=308.15,
        N_stages=9, ins=[P1-0, cooledbg], solute="CO2", outs=('biomethane_outlet','rich_amine'), 
        P=150000
    )
    raw_biogas.set_feed_priority(0) 
    fresh_water.empty() 
    hx2 = bst.HXprocess('HX2', ins=[U102-1, liquid], outs=['heated_amine','lean_amine'])  
    P2 = bst.Pump('P2',ins=hx2-0,P=300000)
    U103 = bst.Stripper('U103',T=393.15, N_stages=9, solute="CO2",ins=P2-0,outs=('gas',liquid),P=300000)
    M1 = bst.Mixer('M1',ins=[amine, water, hx2-1])
    @M1.add_specification(run=True, args=[0.30], impacted_units=[amine.sink])
    def adjust_MEA_content(MEA_fraction):
        MEA_in_amine=amine.imass['Monoethanolamine']
        MEA_in_liquid=liquid.imass['Monoethanolamine']
        total_MEA = MEA_in_amine + MEA_in_liquid
        total_in_mass = sum(stream.F_mass for stream in M1.ins)
        required_MEA_mass= MEA_fraction * total_in_mass
        additional_MEA_needed = required_MEA_mass - total_MEA
        amine.imass['Monoethanolamine'] += additional_MEA_needed
    hx3=bst.HXutility('HX3',ins=M1-0,outs=makeup,T=318.02)
sys.diagram(number=True, kind='cluster')
sys.simulate()

[1226Wang1226]

@yoelcortes, really thank you about your help. I made a very simple mistake, but i've already fixed it:
112.txt

But still can't simulate. Is that the reason that I didn't assign a specific flow rate to the 'water' stream?

[yoelcortes]

@1226Wang1226, I believe it has to do with your specification. I am getting the following after running your code:

>>> sys.flowsheet.amine.show()
Stream: amine to <Mixer: M1>
phase: 'l', T: 298.15 K, P: 101325 Pa
flow (kmol/hr): Monoethanolamine  -0.408

By the way did you know all streams/units are available in the flowsheet?

>>> import biosteam as bst
>>> bst.F.M1 # Give it a shot after running your code!

I will let you scratch your head a bit with the specification. Tip: you'll need to make sure there are not negative flows being set (consider using max(value, 0)).

Thanks,

[1226Wang1226]

@yoelcortes, thank you to pointing that out! I’ll take some time to think it through carefully. 😊

[1226Wang1226]

@yoelcortes , I think I fixed the problem with the M1 Specification, now the out stream of M1 is 30%MEA+70%water, but there is a new issue that the U102, which should function as the Absorber, is behaving like a stripper, and CO2 is not being absorbed by the sorbent.

122.txt

[yoelcortes]

@1226Wang1226, sorry for the delay! I plan to address this issue on Saturday.

[yoelcortes]

Hi @1226Wang1226,

I have 2 recommendations for you:

1. U102 U103 only has one inlet stream. I believe it should be two. Maybe fixing this will help correct the rest of the process.
2. The VLE in BioSTEAM is not good for supercritical components; CO2/CH4 need Henry coefficients to better model. But you can pass partition coefficients to the stages to make it work as it should. For example:

U102 = bst.Absorber(
        'U102', T=308.15,
        N_stages=9, ins=[P1-0, hx1-0], solute="CO2", outs=('biomethane_outlet','rich_amine'), 
        P=150000,
        partition_data={
            'K': np.array([1e-6, 1e-6, 1e3, 1e4, 1e5, 1e9, 1e6]),
            'IDs': ['Water', 'Monoethanolamine', 'CO2', 'CH4', 'H2S', 'N2', 'O2',],
        }
    )

^ This sets the partition coefficients to every stage. But you can also pass different partition coefficients to each specific stage:

U103.stages[1].partition.partition_data ={
            'K': np.array([1e-6, 1e-6, 1e3, 1e4, 1e5, 1e9, 1e6]),
            'IDs': ['Water', 'Monoethanolamine', 'CO2', 'CH4', 'H2S', 'N2', 'O2',],
}

I hope this helps,
Thanks!

[1226Wang1226]

@yoelcortes , thanks for your help, but I still have a question. The code for U102: [P1-0, hx1-0] - doesn't this represent two inlet streams?
By the way, today happens to be my first day back to work after the holidays, so the timing actually works out. I really appreciate you taking the time to answer my question!

[yoelcortes]

@1226Wang1226, Sorry, I meant to say U103 (not U102). Happy the timing worked out well. I was a little worried you might have gotten stuck and started focusing on other stuff.

Thanks,

[1226Wang1226]

@yoelcortes , how can I create a Condenser(P-19/C-104) unit? Or create a stripper with condenser? I couldn't find related instructions in the API reference, and this maybe can help me to fix the problem about U103 inlets. (Apologies for the delayed response. I had to prioritize other tasks over the past period.🥲）