Pump Error with Pseudo-Biomass Chemical: liquid viscosity method 'NEGLECT_P' is not valid

[iilard]

In my process simulation, after fermentation the broth containing different solutes and biomass (which is defined as a pseudo-compound) go through a decanter (assumed using gravity). After the decanter, the concentrated biomass has to be filtered. For this I need a pump (e.g. assuming a pressure filter) beforehand.
However, it seems the pump in BioSTEAM has an issue with the viscosity method 'NEGLECT_P' due to a component with CASRN 'None'. Likely this is the Biomass.
I would only need the pump for it's electricity usage, for my LCA afterwards.

_settings.py:

import thermosteam as tmo
import biosteam as bst
from _chemicals import chemicals 
from thermosteam import settings

#Activate chemicals list & register them in bio/thermosteam
tmo.settings.set_thermo(chemicals) 
bst.settings.set_thermo(chemicals)

_chemicals.py:

import thermosteam as tmo
import biosteam as bst
from thermosteam import Chemicals, Chemical

def create_chemicals():
    chemicals = Chemicals([])
    def add_chemical(ID, ref=None, **data):
        chemical = Chemical(ID, **data) if ref is None else ref.copy(ID, **data)
        chemicals.append(chemical)
        return chemical
    
    Water = add_chemical('H2O')
    Glucose = add_chemical('Glucose', phase='l', rho=1560, Cp=1.213)
    CaCO3 = add_chemical('CaCO3', phase='s', rho=2710, Cp=0.834, default=True)
    CalciumLactate = add_chemical('CalciumLactate', phase='l', Hf=-1686100, rho=1494) # NOTE: Cp value not available (yet), filler could be ca. 1.4, Hf value probably off as for dissociated aq. species... makes whole fermentor endothermic...
    lla = add_chemical('L-LacticAcid', phase='l', Hf=-686300, Cp=2.109, rho=1206)
    SulfuricAcid = add_chemical('H2SO4', phase='l', rho=1840, Cp=1.38)
    CarbonDioxide = add_chemical('CO2', phase='g')
    Gypsum = add_chemical('CaSO4_2H2O', phase='s', rho=2320, MW=172.18, Hf=-2023000, Cp=1.081, CAS='10101-41-4', mu = 0.00095, search_db=False) # NOTE: Einstein-Equation gives 0.00095 sPa for Gypsum viscosity
    Biomass_s = add_chemical('Biomass_s', phase='s', formula='CH1.8O0.5N0.2', MW=24.626, rho=1093, Hf=-130412, Cp=1.25, search_db=False) 
    nutrient_N = add_chemical('NH3', phase='l')
    Octanol = add_chemical('Octanol', phase='l')
    Trioctylamine = add_chemical('Trioctylamine', phase='l')
    SodiumHydroxide = add_chemical('NaOH', phase='l') 
    SodiumSulfate = add_chemical('Na2SO4', phase='l', rho=1200, Cp=3.5, mu = 0.001, search_db=True)

    chemicals.compile()
    return chemicals
chemicals = create_chemicals()

_reactions.py:

import thermosteam as tmo

def fermentation_reaction():
    fermentation = tmo.Reaction(reaction='Glucose -> 1.84 L-LacticAcid + 0.585 Biomass_s', reactant='Glucose', X=1, basis='mol', correct_atomic_balance=False) 
    return fermentation

def neutralization_reaction():
    neutralization = tmo.Reaction(reaction='2 L-LacticAcid + CaCO3 -> CalciumLactate + CO2 + H2O', reactant='L-LacticAcid', X=1, basis='mol')
    return neutralization

def acidification_reaction():
    acidification = tmo.Reaction(reaction='CalciumLactate + H2SO4 -> 2 L-LacticAcid + CaSO4_2H2O', reactant='CalciumLactate', X=1, basis='mol')
    return acidification

def acidification_2_reaction():
    acidification_2 = tmo.Reaction(reaction='CaCO3 + H2SO4 -> CaSO4_2H2O + CO2 + H2O', reactant='CaCO3', X=1, basis='mol')
    return acidification_2

def caustic_wash_reaction():
    caustic_wash = tmo.Reaction(reaction='2 NaOH + H2SO4 -> Na2SO4 + 2 H2O', reactant='H2SO4', X=1, basis='mol')
    return caustic_wash

_units.py:

import biosteam as bst
import thermosteam as tmo
from biosteam import CSTR
import numpy as np
from _reactions import fermentation_reaction, neutralization_reaction, acidification_reaction, acidification_2_reaction

# Custom Fermentor based on CSTR for cont. ferm.
class Fermentor(bst.CSTR):
    _N_ins = 1
    _N_outs = 2
    def __init__(self, ID='Fermentor', ins=None, outs=(), thermo=None, *, T=323.15, **kwargs):
        if outs == ():
            outs = [None, None]  # liquid, gas
        super().__init__(ID, ins, outs, thermo=thermo, **kwargs)
        self.T=T
        self.fermentation_rxn = fermentation_reaction()
        self.neutralization_rxn = neutralization_reaction()

    def _run(self):
        feed = self.ins[0]
        liquid_effluent, gas_vent = self.outs
        liquid_effluent.copy_like(feed)
        # Apply reactions using the class-defined reactions, first parallel fermentation, then neutralization
        self.fermentation_rxn(liquid_effluent.mol)
        self.neutralization_rxn(liquid_effluent.mol)
        # Handle gas separation - remove CO2 from liquid and send to gas vent
        gas_vent.copy_flow(liquid_effluent, 'CO2', remove=True)
        liquid_effluent.phase = 'l'
        gas_vent.phase = 'g'
        liquid_effluent.T = gas_vent.T = self.T


# Custom Acidification Reactor
class AcidificationReactor(bst.CSTR):
    _N_ins = 2
    _N_outs = 2

    def __init__(self, ID='', ins=None, outs=(), P=101325, T=298.15, tau=1.0, V=1.0): # check assumptions
        if outs == ():
            outs = [None, None]
        super().__init__(ID, ins, outs, tau=tau, T=T, P=P)

        self.acidification_rxn = acidification_reaction()
        self.acidification_2_rxn = acidification_2_reaction()
        
    def _run(self):
        feed, acid = self.ins
        effluent, vent = self.outs

        # Acid dosing
        n_CL = feed.imol['CalciumLactate']
        acid.imol['H2SO4'] = n_CL * 1.1
        acid.imass['H2O'] = acid.imass['H2SO4'] / 0.93 * 0.07

        # Mix and pre‑instantiate phases
        effluent.mix_from([feed, acid])
        effluent.phases = ('l', 's')
        effluent.T = self.T
        effluent.P = self.P

        # Reactions
        self.acidification_rxn(effluent)
        self.acidification_2_rxn(effluent)

        # CO2 Vent
        vent.copy_flow(effluent, 'CO2', remove=True)
        vent.phase = 'g'
        vent.T = effluent.T
        vent.P = effluent.P

        # Force gypsum into solid phase (safety net)
        n_total = effluent.imol['CaSO4_2H2O']
        if n_total:
            effluent.imol['l', 'CaSO4_2H2O'] = 0
            effluent.imol['s', 'CaSO4_2H2O'] = n_total

        # Keep outlet as slurry/liquid
        effluent.phase = 'l'

_system.py:

import biosteam as bst
from _units import Fermentor, AcidificationReactor  # custom classes
from _reactions import fermentation_reaction, neutralization_reaction, acidification_reaction, caustic_wash_reaction  # reaction functions
from _settings import chemicals  # compiled thermo package

# -------------------- FEED STREAMS FOR ALL UNITS --------------------
glucose_feed = bst.Stream('glucose_feed', Glucose=2476, Water=28483, units='kg/hr') # 80 g/L
CaCO3_feed = bst.Stream('CaCO3_feed', CaCO3=1277.8, Water=2373, units='kg/hr') # 0.92mol CaCO3 per 1mol Glucose (reactions) --> + excess 1% // 35wt% CaCO3 slurry
H2SO4_feed = bst.Stream('H2SO4_feed', units='kg/hr')
Organic_Solvent = bst.Stream('Organic_Solvent', Octanol=5340.6, Trioctylamine=5340.6, units='kg/hr') # 1.5 : 1 ratio -> org : aq phase
Extr_Water_1 = bst.Stream('Extraction_water_1', H2O=5494.6, units='kg/hr') # Patent Ratio 0.4 : 1 (Water kg : Extract kg)
Extr_Water_2 = bst.Stream('Extraction_water_2', H2O=4695.1, units='kg/hr') # Patent Ratio 0.4 : 1 (Water kg : Extract kg)
Caustic_Sol = bst.Stream('Caustic_Solution', NaOH=123.84, H2O=1548, units='kg/hr')
OrgSolvent_Makeup = bst.Stream('Solvent_Makeup', Octanol=53.2512, Trioctylamine=53.5608, units='kg/hr') # Add the 1% of solvent lost in caustic wash
Recycled_Solvent = bst.Stream('Recycled_Solvent')

# -------------------- SUBSYSTEM 1: CONVERSION --------------------
# Unit and stream definitions
with bst.System('conversion_sys') as conversion_sys:
    feedstock_mixer = bst.Mixer('feedstock_mixer', ins=[glucose_feed, CaCO3_feed], outs=('crude_feed'))
    preheater = bst.HXutility('preheater', feedstock_mixer.outs[0], outs=('heated_feed'), T=323.15) # NOTE: Placeholder 50°C
    fermentor = Fermentor('fermentor', preheater.outs[0], outs=['fermented_broth', 'CO2'], P=101325, T=323.15, tau=72, V_wf=0.8, kW_per_m3=0.05, dT_hx_loop=35)    # NOTE find source for possible kW_per_m3 value for anaerobic ferm.
    ferm_cooler = bst.HXutility('fermentor_cooler', fermentor.outs[0], outs=('cooled_broth'), T=298.15)


# -------------------- SUBSYSTEM 2.1: SEPARATION --------------------
# Biomass Removal --> NOTE: Fine tuning of splits, realism vs. idealism
# Acidification & Gypsum Filtration

with bst.System('separation_sys') as separation_sys:
    gravity_decanter = bst.units.SolidsSeparator('GravityDecanter',
                                            ins=ferm_cooler.outs[0], outs=('decanter_underflow', 'decanter_overflow'),
                                            split={'Biomass_s': 1, 'CaCO3': 0.85, 'CalciumLactate': 0.05}, # NOTE: FINE TUNING, HOW MUCH PRODUCT LOST?
                                            moisture_content=0.35)
 
    slurry_p = bst.Pump('slurry_pump', gravity_decanter.outs[0], outs=('pressurized_decanted_cake'), P=200000, pump_type='Default')

    bm_Filter = bst.units.SolidsSeparator('BM_Filter',
                                          ins=slurry_p.outs[0], outs=('BM_cake', 'BM_filtrate'),
                                          split={'Biomass_s': 1, 'CaCO3': 0.75},
                                          moisture_content=0.08)
    filtrate_mixer = bst.Mixer('filtrate_mixer', ins=(gravity_decanter.outs[1], bm_Filter.outs[1]), outs='clarified_broth')
    acidification_reactor = AcidificationReactor('AcidificationReactor', ins=[filtrate_mixer.outs[0], 'H2SO4_feed'], outs=('acidified_slurry', 'CO2'))
    gypsum_filter = bst.units.SolidsSeparator('GypsumFilter', ins=acidification_reactor.outs[0], outs=('gypsum_cake', 'lactic_acid_solution'), 
                                          split={'CaSO4_2H2O': 0.99}, # Fine particles stay, removed by extraction
                                          moisture_content=0.2)


# -------------------- SUBSYSTEM 2.2A: PURIFICATION --------------------
# MEE 1 to conc. extraction feed
# Extraction with organic amine solvent
# 2 Stage Back-Extraction into fresh water
# MEE 2 to 88wt% lla

with bst.System('purification_sys') as purification_sys:
    Evaporator_1 = bst.units.MultiEffectEvaporator(ID='MEE_pre_extr', ins=[gypsum_filter.outs[1]], outs=('conc_la_sol', 'condensate'), 
                                                   V=0.85, V_definition='Overall', # NOTE adjust to 30wt% lactic acid conc. before extraction for eff.
                                                   P=(101325, 90000, 70000)) 


    ExtrMixer1 = bst.LiquidsMixingTank(ID='Extraction_M1', ins=[Evaporator_1.outs[0], Organic_Solvent], outs=['mixed_phase_1'])
    PreExtr_Cooler = bst.HXutility('extraction_cooler', ins=ExtrMixer1.outs[0], T=313.15)  # 40°C extr feed for optimal eff.
    ExtrSettler1 = bst.LiquidsSplitSettler(ID='Extraction_S1', ins=[PreExtr_Cooler.outs[0]], outs=['organic_phase_1', 'aq_phase_1'],
                                    split={'L-LacticAcid': 0.99, # Simulate two stage extraction in one
                                            'H2SO4': 0.98,
                                            'Octanol': 1,
                                            'Trioctylamine': 1,
                                            'H2O': 0.01, # some water carry-over
                                            'CaCO3': 0,
                                            'CaSO4_2H2O': 0,
                                            'NH3' : 0}) # NOTE "realistic" assumptions of split

    BackExtrMixer1 = bst.LiquidsMixingTank('BackExtr_Mixer1', ins=[ExtrSettler1.outs[0], Extr_Water_1])
    PreBackExtr_Heater1 = bst.HXutility('backextr_heater1', ins=BackExtrMixer1.outs[0], T=348.15) # ca. 20-30°C higher T for Back Extraction
    BackExtrSettler1 = bst.LiquidsSplitSettler('BackExtr_Settler1',
                                               ins=PreBackExtr_Heater1.outs[0],
                                               outs=('back_extr_aq1', 'back_extr_org1'),
                                               split={'L-LacticAcid': 0.85,
                                                   'H2SO4': 0,
                                                   'H2O': 0.99,
                                                   'Octanol': 0,
                                                   'Trioctylamine': 0})

    BackExtrMixer2 = bst.LiquidsMixingTank('BackExtr_Mixer2', ins=[BackExtrSettler1.outs[1], Extr_Water_2])
    PreBackExtr_Heater2 = bst.HXutility('backextr_heater2', ins=BackExtrMixer2.outs[0], T=348.15) # ca. 20-30°C higher T for Back Extraction
    BackExtrSettler2 = bst.LiquidsSplitSettler('BackExtr_Settler2',
                                               ins=PreBackExtr_Heater2.outs[0],
                                               outs=('back_extr_aq2', 'back_extr_org2'),
                                               split={'L-LacticAcid': 0.8, # 80% of remaining LLA (total 97%)
                                                   'H2SO4': 0,
                                                   'H2O': 0.99,
                                                   'Octanol': 0,
                                                   'Trioctylamine': 0})
    AqPhaseMixer = bst.MixTank('PostExtraction_AqPhase', ins=[BackExtrSettler1.outs[0], BackExtrSettler2.outs[0]], outs='pure_lactic_acid_solution')

# -------------------- SUBSYSTEM 2.2B: SOLVENT RECOVERY & RECYCLING --------------------
#Organic solvent washed (neutralized) with aq. NaOH solution

    Caustic_Mixer = bst.LiquidsMixingTank('Caustic_Mixer', ins=[BackExtrSettler2.outs[1], Caustic_Sol], outs=('caustic_mix'))
    CausticWash_Reactor = bst.SinglePhaseReactor('Caustic_Wash', ins=Caustic_Mixer.outs[0], outs=('neutralized_solvent'),
                                                 T=323.15, P=101325, V_wf=0.8,
                                                 tau=0.5, 
                                                 reaction=caustic_wash_reaction())
    Caustic_Settler = bst.LiquidsSplitSettler('Caustic_Settler', 
                                              ins=CausticWash_Reactor.outs[0], 
                                              outs=('caustic_w_waste_brine', 'recovered_solvent'),
                                              split={
                                                 'Octanol': 0.01,
                                                 'Trioctylamine': 0.01,
                                                 'NaOH': 1,
                                                 'Na2SO4': 1,
                                                 'H2O': 1,
                                                 'L-LacticAcid': 1})
    OrgSolvent_Recycler = bst.Mixer('Solvent_Mixer', ins=[Caustic_Settler.outs[1], OrgSolvent_Makeup], outs=Organic_Solvent)

# MEE 2
    Evaporator_2 = bst.MultiEffectEvaporator(ID='MEE_post_extr', ins=[AqPhaseMixer.outs[0]], outs=('product', 'condensate'),
    V=0.95, V_definition='Overall', P=(101325, 80000, 60000, 30000)) # NOTE Fine tuning
    Evaporator_2.split={
        'H2O': 1,
        'L-LacticAcid': 0}
    
# Finisher Flash for 88wt%
    Evaporator_3 = bst.Flash(ID='FlashEvaporator', ins=Evaporator_2.outs[0], outs=('condensate', '88wt_product'), P=30000, V=0.414) # Tuned to give 88wt% LLA


# -------------------- MAIN SYSTEM --------------------
# Combine subsystems into the main system
lactic_acid_system = bst.System('lactic_acid_system',
                                path=[conversion_sys, separation_sys, purification_sys],
                                recycle=[Organic_Solvent])

# SIMULATION 
if __name__ == '__main__':
    lactic_acid_system.simulate()
    print("Simulation completed!")

gravity_decanter.outs[0].show()
gravity_decanter.outs[1].show()
bm_Filter.outs[0].show()
bm_Filter.outs[1].show()

ERROR:

Traceback (most recent call last):
  File "c:\Users\ivano\Desktop\Masterarbeit\Code\_system.py", line 136, in <module>
    lactic_acid_system.simulate()
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\biosteam\_system.py", line 3105, in simulate
    with self.flowsheet:
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\biosteam\_flowsheet.py", line 120, in __exit__
    if exception: raise exception
                  ^^^^^^^^^^^^^^^
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\biosteam\_system.py", line 3166, in simulate
    raise error
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\biosteam\_system.py", line 3154, in simulate
    if design_and_cost: self._summary()
                        ^^^^^^^^^^^^^^^
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\biosteam\_system.py", line 2862, in _summary
    f(i, i._summary)
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\thermosteam\exceptions.py", line 94, in try_method_with_object_stamp
    raise_error_with_object_stamp(object, error)
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\thermosteam\exceptions.py", line 84, in raise_error_with_object_stamp
    raise error
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\thermosteam\exceptions.py", line 88, in try_method_with_object_stamp
    return method(*args)
           ^^^^^^^^^^^^^
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\biosteam\_system.py", line 2862, in _summary
    f(i, i._summary)
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\thermosteam\exceptions.py", line 94, in try_method_with_object_stamp
    raise_error_with_object_stamp(object, error)
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\thermosteam\exceptions.py", line 84, in raise_error_with_object_stamp
    raise error
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\thermosteam\exceptions.py", line 88, in try_method_with_object_stamp
    return method(*args)
           ^^^^^^^^^^^^^
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\biosteam\_unit.py", line 1191, in _summary
    self._design(**design_kwargs) if design_kwargs else self._design()
                                                        ^^^^^^^^^^^^^^
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\biosteam\units\_pump.py", line 175, in _design
    nu = si.nu
         ^^^^^
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\thermosteam\_stream.py", line 1450, in nu
    mu = self.mu
         ^^^^^^^
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\thermosteam\_stream.py", line 1415, in mu
    return self._get_property('mu')
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\thermosteam\_stream.py", line 1351, in _get_property
    property_cache[name] = value = calculate(
                                   ^^^^^^^^^^
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\thermosteam\mixture\ideal_mixture_model.py", line 62, in __call__
    return sum([j * models[i](phase, T, P) for i, j in mol.dct.items()])
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\thermosteam\mixture\ideal_mixture_model.py", line 62, in <listcomp>
    return sum([j * models[i](phase, T, P) for i, j in mol.dct.items()])
                    ^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\thermosteam\base\phase_handle.py", line 131, in __call__
    return self.model(T, P)
           ^^^^^^^^^^^^^^^^
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\thermosteam\thermo\tp_dependent_property.py", line 44, in __call__
    return self.TP_dependent_property(T, P)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\ivano\miniconda3\envs\glukose-env\Lib\site-packages\thermo\utils\tp_dependent_property.py", line 288, in TP_dependent_property
    raise RuntimeError(f"{self.name} method '{method_P}' is not valid at T={T} K and P={P} Pa for component with CASRN '{self.CASRN}'")
RuntimeError: <System: separation_sys> <Pump: slurry_pump> liquid viscosity method 'NEGLECT_P' is not valid at T=298.15 K and P=101325.0 Pa for component with CASRN 'None'

What should happen is that the pump increases the pressure of the fermentation broth to 200 kPa for the filter to work. Obviously a centrifugal pump wouldn't make sense here as the biomass is very dense (low moisture and solute content).

• Is there a way to make the pump work or would you recommend another approach for such dense mixtures (and pseudo compound)?

Alternatively I will have to use a ScrewPress, but then I will neglect the electricity usage in my LCA and it won't be accurate in terms of representing the process description I'm using.

[iilard]

UPDATE:
I just randomly chose a mu value, it didn't even influence power usage at all. Is that normal? Is a basic hydraulic pump formula used here?