SMB Builder#
To facilitate the setup of SMB models, an SMBBuilder is provided which automatically configures a CarouselBuilder as a 4-Zone SMB.
For it to work, it requires fully configured eluent and feed Inlets, as well as a column object.
To demonstrate this, consider the following component system, isotherm, and column model:
Show code cell source
from CADETProcess.processModel import ComponentSystem
from CADETProcess.processModel import Linear
from CADETProcess.processModel import Inlet, LumpedRateModelWithPores
# Component System
component_system = ComponentSystem(['A', 'B'])
# Binding Model
binding_model = Linear(component_system)
binding_model.is_kinetic = True
binding_model.adsorption_rate = [2, 3]
binding_model.desorption_rate = [1, 1]
# Column
column = LumpedRateModelWithPores(component_system, name='column')
column.binding_model = binding_model
column.length = 0.6
column.diameter = 0.025
column.bed_porosity = 0.4
column.particle_porosity = 0.7
column.particle_radius = 5.0e-6
column.film_diffusion = component_system.n_comp*[1e-5]
column.axial_dispersion = 1e-8
eluent = Inlet(component_system, name='eluent')
eluent.c = [0, 0]
eluent.flow_rate = 7e-7
feed = Inlet(component_system, name='feed')
feed.c = [10, 10]
feed.flow_rate = 4e-7
These objects are now passed to the SMBBuilder, which inherits from CarouselBuilder.
Consequently, switch time and output states can be specified as before.
Note, that the names of the automatically generated zones are: zone_I zone_II zone_III zone_IV.
from CADETProcess.modelBuilder import SMBBuilder
smb_builder = SMBBuilder(feed, eluent, column)
smb_builder.switch_time = 100
w_e = 0.14
smb_builder.set_output_state('zone_I', [w_e, 1-w_e])
w_r = 0.13
smb_builder.set_output_state('zone_III', [w_r, 1-w_r])
Again, the Process needs to be built before simulation.
process = smb_builder.build_process()
from CADETProcess.simulator import Cadet
process_simulator = Cadet()
process_simulator.n_cycles = 3
simulation_results = process_simulator.simulate(process)
_ = simulation_results.solution.raffinate.inlet.plot()
_ = simulation_results.solution.extract.inlet.plot()
SMB Design#
Warning
This functionality is still work in progress. Changes in the interface are to be expected.
Several shortcut methods exist for the design of SMB systems. Most famously, the so-called triangle theory can be used to determine flow rates of the individual zones.
However, these methods highly depend on the adsorption behaviour of the components.
In CADET-Process, design methods for two-component Linear and Langmuir models are provided.
For this purpose, specialized SMBBuilder classes need to be used.
Considering the same parameters as above, a LinearSMBBuilder needs to be imported.
The triangle_design() method returns the values for Q_feed, Q_eluent, w_r, and w_e.
By default, these values are also set automatically in the SMB builder.
from CADETProcess.modelBuilder import LinearSMBBuilder
smb_builder = LinearSMBBuilder(feed, eluent, column)
smb_builder.switch_time = 100
Q_feed, Q_eluent, w_r, w_e = smb_builder.triangle_design()
print(Q_feed, Q_eluent, w_r, w_e)
5.301437602932773e-07 5.301437602932773e-07 0.13235294117647053 0.13235294117647053
/home/docs/checkouts/readthedocs.org/user_builds/cadet-process/conda/latest/lib/python3.11/site-packages/CADETProcess/modelBuilder/carouselBuilder.py:908: UserWarning: Isotherm uses kinetic binding, however, triangle theory assumes instant equilibrium.
warnings.warn(
To account for non-idealities, such as axial dispersion or adsorption kinetics, a safety factor gamma can also be provided which moves the operating point from the theoretical optimum towards the middle of the triangle, ensuring the purity of the products.
Q_feed, Q_eluent, w_r, w_e = smb_builder.triangle_design(gamma=1.05)
print(Q_feed, Q_eluent, w_r, w_e)
4.013945613649104e-07 6.601552062699625e-07 0.12847965738758033 0.13626532083633752
Moreover, the triangle region can also be plotted.
_ = smb_builder.plot_triangle(gamma=1.05)
Running the simulation is equivalent to before.
process = smb_builder.build_process()
from CADETProcess.simulator import Cadet
process_simulator = Cadet()
process_simulator.n_cycles = 3
simulation_results = process_simulator.simulate(process)
_ = simulation_results.solution.raffinate.inlet.plot()
_ = simulation_results.solution.extract.inlet.plot()
