# -*- coding: utf-8 -*-
# BioSTEAM: The Biorefinery Simulation and Techno-Economic Analysis Modules
# Copyright (C) 2020-2023, Yoel Cortes-Pena <yoelcortes@gmail.com>
#
# This module is under the UIUC open-source license. See
# github.com/BioSTEAMDevelopmentGroup/biosteam/blob/master/LICENSE.txt
# for license details.
"""
.. contents:: :local:
.. autoclass:: biosteam.units.vacuum_system.VacuumSystem
"""
from . import design_tools as design
from .auxiliary import Auxiliary
from typing import Optional, Union
import biosteam as bst
from .._unit import Unit
__all__ = ('VacuumSystem',)
[docs]
class VacuumSystem(Auxiliary):
"""
Create an auxiliary vacuum system for a unit operation.
Parameters
----------
unit :
Main unit operation containing the auxiliary vacuum system. Missing parameters
are estimated through this unit operation, if given.
F_mass :
Vapor mass flow rate entering vacuum system from vessel [kg/hr] (not including inleakage).
Defaults to the vapor volumetric flow rate exiting `unit`.
F_vol :
Vapor volumetric flow rate entering vacuum system from vessel [m3/hr] (not including inleakage).
Defaults to the vapor mass flow rate exiting `unit`.
P_suction :
Suction pressure [Pa]. Defaults to `unit.P` or the minimum outlet pressure.
vessel_volume :
Vacuum volume [m3]. Defaults to `unit.design_results['Total volume']`.
vacuum_system_preference :
Name(s) of preferred vacuum systems. Valid names include 'Liquid-ring pump',
'Steam-jet ejector', and 'Dry-vacuum pump'.
Notes
-----
The vacuum system is sized/costed based on the vapor flow rate through the
vacuum system, which includes the inleakage into the vessel through fixtures
and cracks. The inleakage is a function of the suction pressure and the
total vessel volume as in [1]_.
BioSTEAM's CSTR, Flash, and Distillation columns automatically include a
vacuum system when needed.
Examples
--------
Create vessel with a vacuum system:
>>> import biosteam as bst
>>> class VacuumVessel(bst.Unit):
... auxiliary_unit_names = ('vacuum_system',) # Mark attributes as auxiliary
... _units = {'Total volume': 'm3'} # This is needed for the vacuum system
... P = 1000 # Pa
... tau = 4 # hr
...
... def _run(self):
... self.outs[0].P = 1000 # Pa
...
... def _design(self):
... self.design_results['Total volume'] = self.feed.F_vol * self.tau
... self.vacuum_system = bst.VacuumSystem(self)
...
>>> bst.settings.set_thermo(['Water'])
>>> feed = bst.Stream('feed', Water=1e6)
>>> V1 = VacuumVessel('V1', ins=feed)
>>> V1.simulate()
>>> V1.results()
Vacuum vessel Units V1
Medium pressure steam Duty kJ/hr 1.04e+07
Flow kmol/hr 288
Cost USD/hr 79.3
Cooling water Duty kJ/hr -9.37e+06
Flow kmol/hr 6.4e+03
Cost USD/hr 3.12
Design Total volume m3 7.23e+04
Purchase cost Vacuum system - Steam-jet ejecto... USD 8.18e+04
Total purchase cost USD 8.18e+04
Utility cost USD/hr 82.4
For simplicity, this example does not include the cost of the vessel, but
vessel costs should be included for techno-economic analysis.
References
----------
.. [1] Seider, W. D.; Lewin, D. R.; Seader, J. D.; Widagdo, S.; Gani, R.;
Ng, M. K. Cost Accounting and Capital Cost Estimation.
In Product and Process Design Principles; Wiley, 2017; pp 426–485.
"""
__slots__ = (
'power_utility',
'heat_utilities',
'baseline_purchase_costs',
'purchase_costs',
'installed_costs',
'F_M', 'F_D', 'F_P', 'F_BM',
'owner',
)
def __init__(self,
unit: Optional[Unit]=None,
vacuum_system_preference: Optional[str]=None,
F_mass: Optional[float]=None,
F_vol: Optional[float]=None,
P_suction: Optional[float]=None,
vessel_volume: Optional[Union[float, list[float]]]=None
):
super().__init__()
if unit:
# Deduce arguments if unit given
if F_mass is None or F_vol is None:
# If vapor is condensed, assume vacuum system is after condenser
vents = [i for i in unit.outs if 'g' in i.phase]
F_mass = 0.
F_vol = 0.
for vapor in vents:
hx = vapor.sink
if isinstance(hx, bst.HX):
index = hx.ins.index(vapor)
vapor = hx.outs[index]
if 'g' not in vapor.phase: continue
if isinstance(vapor, bst.MultiStream):
F_mass += vapor['g'].F_mass
F_vol += vapor['g'].F_vol
else:
F_mass += vapor.F_mass
F_vol += vapor.F_vol
if P_suction is None:
P_suction = getattr(unit, 'P', None) or getattr(unit, 'P_suction', None)
if P_suction is None: P_suction = min([i.P for i in unit.outs])
if vessel_volume is None:
if 'Total volume' in unit.design_results:
vessel_volume = unit.get_design_result('Total volume', 'm3')
else:
raise ValueError("'Total volume' was not found in design results; "
"'vessel_volume' parameter could not be deduced")
else:
# In case user does not supply all arguments
params = [('F_mass', F_mass),
('F_vol', F_vol),
('P_suction', P_suction),
('vessel_volume', vessel_volume)]
for name, value in params:
if value is None:
raise ValueError(
f"missing argument '{name}'; cannot deduce '{name}'"
"when no unit is specified"
)
capex = self.baseline_purchase_costs # Assume all costs the same
vacuum_results = design.compute_vacuum_system_power_and_cost(
F_mass, F_vol, P_suction, vessel_volume, vacuum_system_preference
)
name = vacuum_results['Name']
capex[name] = vacuum_results['Cost']
heating_agent = vacuum_results['Heating agent']
if heating_agent: # Steam turbine
vacuum_steam = self.create_heat_utility()
vacuum_steam.set_utility_by_flow_rate(heating_agent, vacuum_results['Steam flow rate'])
if vacuum_results['Condenser']:
self.add_heat_utility(-vacuum_steam.unit_duty, 373.15) # Vacuum cooling water
self.add_power_utility(vacuum_results['Work'])