Reaction

class thermosteam.reaction.Reaction(reaction, reactant, X, chemicals=None, basis='mol', *, phases=None, check_mass_balance=False, check_atomic_balance=False, correct_atomic_balance=False, correct_mass_balance=False)[source]

Create a Reaction object which defines a stoichiometric reaction and conversion. A Reaction object is capable of reacting the material flow rates of a thermosteam.Stream object.

Parameters

reaction (dict or str) – A dictionary of stoichiometric coefficients or a stoichiometric equation written as: i1 R1 + … + in Rn -> j1 P1 + … + jm Pm
reactant (str) – ID of reactant compound.
X (float) – Reactant conversion (fraction).
chemicals=None (Chemicals, defaults to settings.chemicals.) – Chemicals corresponing to each entry in the stoichiometry array.
basis='mol' ({'mol', 'wt'}) – Basis of reaction.
check_mass_balance=False (bool) – Whether to check if mass is not created or destroyed.
correct_mass_balance=False (bool) – Whether to make sure mass is not created or destroyed by varying the reactant stoichiometric coefficient.
check_atomic_balance=False (bool) – Whether to check if stoichiometric balance by atoms cancel out.
correct_atomic_balance=False (bool) – Whether to correct the stoichiometry according to the atomic balance.

Notes

A reaction object can react either a stream or an array. When a stream is passed, it reacts either the mol or mass flow rate according to the basis of the reaction object. When an array is passed, the array elements are reacted regardless of what basis they are associated with.

Warning

Negative conversions and conversions above 1.0 are fair game (allowed), but may lead to odd/infeasible values when reacting a stream.

Examples

Electrolysis of water to molecular hydrogen and oxygen:

>>> import thermosteam as tmo
>>> chemicals = tmo.Chemicals(['H2O', 'H2', 'O2'], cache=True)
>>> tmo.settings.set_thermo(chemicals)
>>> reaction = tmo.Reaction('2H2O,l -> 2H2,g + O2,g', reactant='H2O', X=0.7)
>>> reaction.show() # Note that the default basis is by 'mol'
Reaction (by mol):
 stoichiometry             reactant    X[%]
 H2O,l -> H2,g + 0.5 O2,g  H2O,l       70.00
>>> reaction.reactant # The reactant is a tuple of phase and chemical ID
('l', 'H2O')
>>> feed = tmo.Stream('feed', H2O=100)
>>> feed.phases = ('g', 'l') # Gas and liquid phases must be available
>>> reaction(feed) # Call to run reaction on molar flow
>>> feed.show() # Notice how 70% of water was converted to product
MultiStream: feed
 phases: ('g', 'l'), T: 298.15 K, P: 101325 Pa
 flow (kmol/hr): (g) H2   70
                     O2   35
                 (l) H2O  30

Let’s change to a per ‘wt’ basis:

>>> reaction.basis = 'wt'
>>> reaction.show()
Reaction (by wt):
 stoichiometry                     reactant    X[%]
 H2O,l -> 0.112 H2,g + 0.888 O2,g  H2O,l       70.00

Although we changed the basis, the end result is the same if we pass a stream:

>>> feed = tmo.Stream('feed', H2O=100)
>>> feed.phases = ('g', 'l')
>>> reaction(feed) # Call to run reaction on mass flow
>>> feed.show() # Notice how 70% of water was converted to product
MultiStream: feed
 phases: ('g', 'l'), T: 298.15 K, P: 101325 Pa
 flow (kmol/hr): (g) H2   70
                     O2   35
                 (l) H2O  30

If chemicals phases are not specified, Reaction objects can react a any single phase Stream object (regardless of phase):

>>> reaction = tmo.Reaction('2H2O -> 2H2 + O2', reactant='H2O', X=0.7)
>>> feed = tmo.Stream('feed', H2O=100, phase='g')
>>> reaction(feed)
>>> feed.show()
Stream: feed
 phase: 'g', T: 298.15 K, P: 101325 Pa
 flow (kmol/hr): H2O  30
                 H2   70
                 O2   35

Alternatively, it’s also possible to react an array (instead of a stream):

>>> import numpy as np
>>> array = np.array([100., 0. , 0.])
>>> reaction(array)
>>> array
array([30., 70., 35.])

Reaction objects with the same reactant can be added together:

>>> tmo.settings.set_thermo(['Glucose', 'Ethanol', 'H2O', 'O2', 'CO2'])
>>> fermentation = tmo.Reaction('Glucose + O2 -> Ethanol + CO2', reactant='Glucose', X=0.7)
>>> combustion = tmo.Reaction('Glucose + O2 -> H2O + CO2', reactant='Glucose', X=0.2)
>>> mixed_reaction = fermentation + combustion
>>> mixed_reaction.show()
Reaction (by mol):
 stoichiometry                                    reactant    X[%]
 Glucose + O2 -> 0.778 Ethanol + 0.222 H2O + CO2  Glucose    90.00

Note how conversions are added and the stoichiometry rescales to a per reactant basis. Conversly, reaction objects may be substracted as well:

>>> combustion = mixed_reaction - fermentation
>>> combustion.show()
Reaction (by mol):
 stoichiometry                reactant    X[%]
 Glucose + O2 -> H2O + CO2  Glucose    20.00

When a Reaction object is multiplied (or divided), a new Reaction object with the conversion multiplied (or divided) is returned:

>>> combustion_multiplied = 2 * combustion
>>> combustion_multiplied.show()
Reaction (by mol):
 stoichiometry                reactant    X[%]
 Glucose + O2 -> H2O + CO2  Glucose    40.00
>>> fermentation_divided = fermentation / 2
>>> fermentation_divided.show()
Reaction (by mol):
 stoichiometry                  reactant    X[%]
 Glucose + O2 -> Ethanol + CO2  Glucose    35.00

copy(basis=None)[source]: Return copy of Reaction object.

force_reaction(material)[source]: React material ignoring feasibility checks.

product_yield(product, basis=None)[source]: Return yield of product per reactant.

adiabatic_reaction(stream)[source]

React stream material adiabatically, accounting for the change in enthalpy due to the heat of reaction.

Examples

Note how the stream temperature changed after the reaction due to the heat of reaction:

>>> import thermosteam as tmo
>>> chemicals = tmo.Chemicals(['H2', 'O2', 'H2O'], cache=True)
>>> tmo.settings.set_thermo(chemicals)
>>> reaction = tmo.Reaction('2H2 + O2 -> 2H2O', reactant='H2', X=0.7)
>>> s1 = tmo.Stream('s1', H2=10, O2=20, H2O=1000, T=373.15, phase='g')
>>> s2 = tmo.Stream('s2')
>>> s2.copy_like(s1) # s1 and s2 are the same
>>> s1.show() # Before reaction
Stream: s1
 phase: 'g', T: 373.15 K, P: 101325 Pa
 flow (kmol/hr): H2   10
                 O2   20
                 H2O  1e+03

>>> reaction.show()
Reaction (by mol):
 stoichiometry       reactant    X[%]
 H2 + 0.5 O2 -> H2O  H2         70.00

>>> reaction(s1)
>>> s1.show() # After isothermal reaction
Stream: s1
 phase: 'g', T: 373.15 K, P: 101325 Pa
 flow (kmol/hr): H2   3
                 O2   16.5
                 H2O  1.01e+03

>>> reaction.adiabatic_reaction(s2)
>>> s2.show() # After adiabatic reaction
Stream: s2
 phase: 'g', T: 421.6 K, P: 101325 Pa
 flow (kmol/hr): H2   3
                 O2   16.5
                 H2O  1.01e+03

property dH: Heat of reaction at given conversion. Units are in either J/mol-reactant or J/g-reactant; depending on basis.

Warning

Latents heats of vaporization are not accounted for; only heats of formation are included in this term. Note that heats of vaporization are temperature dependent and cannot be calculated using a Reaction object.

property X: [float] Reaction converion as a fraction.

property stoichiometry: [array] Stoichiometry coefficients.

property istoichiometry: [ChemicalIndexer] Stoichiometry coefficients.

property reactant: [str] Reactant associated to conversion.

property MWs: [1d array] Molecular weights of all chemicals [g/mol].

property basis: {‘mol’, ‘wt’} Basis of reaction

check_mass_balance(tol=0.001)[source]: Check that stoichiometric mass balance is correct.

check_atomic_balance(tol=0.001)[source]: Check that stoichiometric atomic balance is correct.

correct_mass_balance(variable=None)[source]: Make sure mass is not created or destroyed by varying the reactant stoichiometric coefficient.

correct_atomic_balance(constants=None)[source]

Correct stoichiometry coffecients to satisfy atomic balance.

Parameters: constants (str, optional) – IDs of chemicals for which stoichiometric coefficients are held constant.

Examples

Balance glucose fermentation to ethanol:

>>> import thermosteam as tmo
>>> from biorefineries import lipidcane as lc
>>> tmo.settings.set_thermo(lc.chemicals)
>>> fermentation = tmo.Reaction('Glucose + O2 -> Ethanol + CO2',
...                             reactant='Glucose',  X=0.9)
>>> fermentation.correct_atomic_balance()
>>> fermentation.show()
Reaction (by mol):
 stoichiometry                 reactant    X[%]
 Glucose -> 2 Ethanol + 2 CO2  Glucose    90.00

Balance methane combustion:

>>> combustion = tmo.Reaction('CH4 + O2 -> Water + CO2',
...                           reactant='CH4', X=1)
>>> combustion.correct_atomic_balance()
>>> combustion.show()
Reaction (by mol):
 stoichiometry                reactant    X[%]
 2 O2 + CH4 -> 2 Water + CO2  CH4       100.00

Balance electrolysis of water (with chemical phases specified):

>>> electrolysis = tmo.Reaction('H2O,l -> H2,g + O2,g',
...                             chemicals=tmo.Chemicals(['H2O', 'H2', 'O2']),
...                             reactant='H2O', X=1)
>>> electrolysis.correct_atomic_balance()
>>> electrolysis.show()
Reaction (by mol):
 stoichiometry             reactant    X[%]
 H2O,l -> H2,g + 0.5 O2,g  H2O,l     100.00

Note that if the reaction is underspecified, there are infinite ways to balance the reaction and a runtime error is raised:

>>> rxn_underspecified = tmo.Reaction('CH4 + Glucose + O2 -> Water + CO2',
...                                   reactant='CH4', X=1)
>>> rxn_underspecified.correct_atomic_balance()
Traceback (most recent call last):
RuntimeError: reaction stoichiometry is underspecified; pass the
`constants` argument to the `<Reaction>.correct_atomic_balance` method
to specify which stoichiometric coefficients to hold constant

Chemical coefficients can be held constant to prevent this error:

>>> rxn_underspecified = tmo.Reaction('CH4 + Glucose + O2 -> Water + CO2',
...                                   reactant='CH4', X=1)
>>> rxn_underspecified.correct_atomic_balance(['Glucose', 'CH4'])
>>> rxn_underspecified.show()
Reaction (by mol):
 stoichiometry                            reactant    X[%]
 Glucose + 8 O2 + CH4 -> 8 Water + 7 CO2  CH4       100.00