stirred_tank_reactor#

class AbstractStirredTankReactor(ID='', ins=None, outs=(), thermo=None, **kwargs)[source]#

Abstract class for a stirred tank reactor, modeled as a pressure vessel with a given aspect ratio and residence time. A pump-heat exchanger recirculation loop is used to satisfy the duty, if any. By default, a turbine agitator is also included if the power usage,`kW_per_m3` , is positive. A vacuum system is also automatically added if the operating pressure is at a vacuum.

Parameters:

tau – Residence time [hr].
T – Operating temperature [K].
P – Operating pressure [Pa].
dT_hx_loop – Maximum change in temperature for the heat exchanger loop. Defaults to 5 K.
V_wf – Fraction of working volume over total volume. Defaults to 0.8.
V_max – Maximum volume of a reactor [m3]. Defaults to 355.
kW_per_m3 – Power usage of agitator. Defaults to 0.985 [kW / m3] converted from 5 hp/1000 gal as in [1], for liquid–liquid reaction or extraction.
vessel_material – Vessel material. Defaults to ‘Stainless steel 316’.
vessel_type – Vessel type. Valid options are ‘Horizontal’ or ‘Vertical’. Defaults to ‘Vertical’
batch – Whether to use batch operation mode. If False, operation mode is continuous. Defaults to continuous.
tau_0 – Cleaning and unloading time (if batch mode). Defaults to 3 hr.
N_reactors – Number of reactors.

Notes

The recirculation loop takes into account the required flow rate needed to reach the maximum temperature change of the heat exchanger, dT_hx_loop. Increasing dT_hx_loop decreases the required recirculation flow rate and therefore decreases pump costs.

When parallel reactors are required, one recirculation loop (each with a pump and heat exchanger) is assumed. Although it is possible to use the same recirculation loop for all reactors, this conservative assumption allows for each reactor to be operated independently from each other.

The capital cost for agitators are not yet included in

Examples

Inherit from AbstractStirredTankReactor to create a new class that simulates the continuous fermentative production of ethanol from sugarcane juice:

>>> import biosteam as bst
>>> class ContinuousFermentation(bst.CSTR):
...     _N_ins = 1
...     _N_outs = 2
...     T_default = 32. + 273.15
...     P_default = 101325.
...     tau_default = 8.
...
...     def _setup(self):
...         super()._setup()
...         chemicals = self.chemicals
...         self.hydrolysis_reaction = bst.Reaction('Sucrose + Water -> 2Glucose', 'Sucrose', 1.00, chemicals)
...         self.fermentation_reaction = bst.Reaction('Glucose -> 2Ethanol + 2CO2',  'Glucose', 0.9, chemicals)
...         self.cell_growth_reaction = cell_growth = bst.Reaction('Glucose -> Yeast', 'Glucose', 0.70, chemicals, basis='wt')
...
...     def _run(self):
...         vent, effluent = self.outs
...         effluent.mix_from(self.ins, energy_balance=False)
...         self.hydrolysis_reaction(effluent)
...         self.fermentation_reaction(effluent)
...         self.cell_growth_reaction(effluent)
...         effluent.T = vent.T = self.T
...         effluent.P = vent.P = self.P
...         vent.phase = 'g'
...         vent.empty()
...         vent.receive_vent(effluent, energy_balance=False)
...
>>> from biorefineries.sugarcane import chemicals
>>> bst.settings.set_thermo(chemicals)
>>> feed = bst.Stream('feed',
...                   Water=1.20e+05,
...                   Glucose=1.89e+03,
...                   Sucrose=2.14e+04,
...                   DryYeast=1.03e+04,
...                   units='kg/hr',
...                   T=32+273.15)
>>> R1 = ContinuousFermentation('R1', ins=feed, outs=('CO2', 'product'))
>>> R1.simulate()
>>> R1.show()
ContinuousFermentation: R1
ins...
[0] feed
    phase: 'l', T: 305.15 K, P: 101325 Pa
    flow (kmol/hr): Water    6.66e+03
                    Glucose  10.5
                    Sucrose  62.5
                    Yeast    456
outs...
[0] CO2
    phase: 'g', T: 305.15 K, P: 101325 Pa
    flow (kmol/hr): Water    9.95
                    Ethanol  3.71
                    CO2      244
[1] product
    phase: 'l', T: 305.15 K, P: 101325 Pa
    flow (kmol/hr): Water    6.59e+03
                    Ethanol  240
                    Glucose  4.07
                    Yeast    532

>>> R1.results()
Continuous fermentation                                    Units                   R1
Electricity         Power                                     kW             1.04e+03
                    Cost                                  USD/hr                 81.5
Chilled water       Duty                                   kJ/hr            -1.41e+07
                    Flow                                 kmol/hr             9.42e+03
                    Cost                                  USD/hr                 70.3
Design              Reactor volume                            m3                  319
                    Residence time                            hr                    8
                    Vessel type                                              Vertical
                    Length                                    ft                 50.5
                    Diameter                                  ft                 16.8
                    Weight                                    lb             5.39e+04
                    Wall thickness                            in                0.363
                    Vessel material                               Stainless steel 316
Purchase cost       Vertical pressure vessel (x4)            USD             1.18e+06
                    Platform and ladders (x4)                USD             2.12e+05
                    Heat exchanger - Floating head (x4)      USD             1.61e+05
                    Recirculation pump - Pump (x4)           USD              3.9e+04
                    Recirculation pump - Motor (x4)          USD             2.78e+03
                    Agitator - Agitator (x4)                 USD             4.53e+05
Total purchase cost                                          USD             2.05e+06
Utility cost                                              USD/hr                  152

References