Re: [cantera-users] Oxidation and reduction of metals

[Steven DeCaluwe]

Hi Vincent,

Not sure if anyone has responded to this yet, or not, but the product surface species can represent whatever species you want to define.  If you have the thermodynamics and kinetics for a gas-surface reaction that results in NiO rather than Ni-O, then you can certainly input those parameters.  You can even have both species present, a Ni-O species that can then become NiO, if you so choose.  Or you can just have a single reaction that results in NiO.  It all depends on what you want to model and what you have reliable parameters for, I suppose.

The key to the language that you reference is that the resulting NiO is a surface NiO, not bulk-phase NiO.  You can then define a separate reaction whereby the NiO moves from the surface into the bulk, something along the lines of:

"NiO(s) + Ni(b) <=> Ni(s) + NiO(b)"

where (s) and (b) represent surface- and bulk-phase species, respectively.  If you want the bulk oxidation to be one-step (or quasi one-step), you can just make the rate constant for this second reaction very fast, thereby keeping the surface and bulk at or near equilibrium.

Cheers,

Steven

On Apr 19, 2013, at 2:46 AM, Vincent Lawlor <vla...@gmail.com> wrote:

Dear All

I have done a little more reading and came across the following in the user guide:

"sticking_prob:

The reactive sticking probability for the forward direction. This can only be specified if there is only one

bulk-phase reactant and it belongs to an ideal gas phase."

I guess this implies that only one hetrogenoius reacting material may be on the interface surface, and that the sticking potential of any species in the gas phase always refers to this material ? 

Thus: O(S) is not really NIO (on the NI surface) It's Ni with an O covering it ? 

Would this imply that the more O covering the NI the higher the potential to form NIO ?

Any tips would be greatly appreciated

Vincent Lawlor

On Thursday, 18 April 2013 17:24:34 UTC+2, Vincent Lawlor wrote:

Dear All,

I would greatly appreciate if anyone could give some guidance regarding the generation of .cti files when a surface can be oxidised or reduced.

As a start, just implement the reduced and oxidised form of a metal I tried the following 

 units(length = "cm", time = "s", quantity = "mol", act_energy = "J/mol")

# gas mixture 

ideal_gas(name = "gas",

         elements = "O H",

         species = """gri30: H2      H       O       O2   """,

          transport = 'Mix',

          #reactions = 'gri30: all',

          options = ['skip_undeclared_elements',

                     'skip_undeclared_species'],

          initial_state = state(temperature = 1073.0, pressure = OneAtm,

mole_fractions = 'H2:0.5, O2:0.5')

          )

ideal_interface(name = "Ni_surf",

                elements = " Ni  H  O ",

                species = """ NI(S) H(S) O(S) NIO(S)", """,

                phases = "gas",

                site_density = 25e-9,

                reactions = "all",

                initial_state = state(temperature = 1073.0,

                                      coverages = 'O(S):0.00, NI(S):1, H(S):0.00, NIO(S):0.00')

                )

#  Species data

species(name = "NI(S)",

    atoms = " Ni:1 ",

    thermo = (

       NASA( [  300.00,  1000.00], [  0.000000000E+00,   0.000000000E+00, 

                0.000000000E+00,   0.000000000E+00,   0.000000000E+00,

                0.000000000E+00,   0.000000000E+00] ),

       NASA( [ 1000.00,  3000.00], [  0.000000000E+00,   0.000000000E+00, 

                0.000000000E+00,   0.000000000E+00,   0.000000000E+00,

                0.000000000E+00,   0.000000000E+00] )

             )

       )

species(name = "O(S)",

atoms = " O:1 Ni:1 ",

thermo = (

NASA( [ 500.00, 2000.00], [ 9.33885773E-01, 1.49287485E-03,

-1.51153811E-06, 7.60133452E-10, -1.42499395E-13,

-2.88011883E+04, -3.47247502E+00] ),

NASA( [ 2000.00, 2000.00], [ 9.33885773E-01, 1.49287485E-03,

-1.51153811E-06, 7.60133452E-10, -1.42499395E-13,

-2.88011883E+04, -3.47247502E+00] )

)

)

species(name = "H(S)",

atoms = " H:1 Ni:1 ",

thermo = (

NASA( [ 500.00, 2000.00], [ 1.38522354E+00, -3.60291509E-05,

1.01482878E-06, -6.39234047E-10, 1.26064639E-13,

-5.45886573E+03, -5.04262898E+00] ),

NASA( [ 2000.00, 2000.00], [ 1.38522354E+00, -3.60291509E-05,

1.01482878E-06, -6.39234047E-10, 1.26064639E-13,

-5.45886573E+03, -5.04262898E+00] )

)

)

#-------------------------------------------------------------------------------

#  Reaction data 

#-------------------------------------------------------------------------------

# Reaction 1

surface_reaction("O2 + 2 NI(S) => 2 O(S)", stick(1.000E-002, 0.00, 0.0))

# Reaction 2

surface_reaction("2 O(S) => O2 + 2 NI(S)", Arrhenius(4.283E+023, 0.00, 474900))

I had thought that if one wished to add NIO that i would simply add

species(name = "NIO(S)",

    atoms = " Ni:1 O:1",

    thermo = (

       NASA( [  300.00,  1000.00], [  0.000000000E+00,   0.000000000E+00, 

                0.000000000E+00,   0.000000000E+00,   0.000000000E+00,

                0.000000000E+00,   0.000000000E+00] ),

       NASA( [ 1000.00,  3000.00], [  0.000000000E+00,   0.000000000E+00, 

                0.000000000E+00,   0.000000000E+00,   0.000000000E+00,

                0.000000000E+00,   0.000000000E+00] )

             )

       )

but I have soticed that the species OS is defined as follows

species(name = "O(S)",

atoms = " O:1 Ni:1 ",

For an interface is there a way to have a second solid material on it ? I would eventually like to oxidise and reduce the metal.

Any tips would be greatly appreciated

Vincent 

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[Anil Kunwar]

Hi All,

I found this discussion along with another this https://groups.google.com/forum/#!searchin/cantera-users/oxidation$20in$20metals%7Csort:date/cantera-users/tt8md7xIUOo/4rrsQaF1d8wJ discussion about the oxidation/reduction chemistry on metals?

Has there been any update or developments of literature work on using oxidation/reduction chemical kinetics of metal surface on Cantera?

Yours Sincerely,

Anil Kunwar

[Steven DeCaluwe]

Hi Anil,

I’m not 100% sure what you are asking here.

1.  If you are asking whether Cantera’s heterogeneous capabilities have changed since these previous email threads, I would say that the answer is “basically no.” That said, as my previous answer describes, I think these capabilities are sufficient to model metal oxidation and reduction.  The user will still need to provide the necessary thermodynamic and kinetic parameters.

2. If you are asking if these parameters are now available in the literature somewhere, I could not answer that.  The question is generally beyond the scope of this email list (i.e. it is a science question, not necessarily a software question), but there is a chance that someone on this list knows the answer.

Best,

Steven 

——————————————————————————————————

Steven DeCaluwe, PhD

Assistant Professor of Mechanical Engineering

Colorado School of Mines

Brown Building W410B

Golden, CO 80401

email: deca...@mines.edu

phone: (303) 273-3666

Twitter: @CORESresearch
http://inside.mines.edu/~decaluwe/

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[Anil Kunwar]

Dear Steven,

I was asking question related to Answer 1 (and I am happy that you elaborated it very vividly).

Yours Sincerely,

Anil Kunwar

On Monday, September 3, 2018 at 3:29:10 PM UTC+2, S. DeCaluwe wrote:

Hi Anil,

I’m not 100% sure what you are asking here.

1.  If you are asking whether Cantera’s heterogeneous capabilities have changed since these previous email threads, I would say that the answer is “basically no.” That said, as my previous answer describes, I think these capabilities are sufficient to model metal oxidation and reduction.  The user will still need to provide the necessary thermodynamic and kinetic parameters.

2. If you are asking if these parameters are now available in the literature somewhere, I could not answer that.  The question is generally beyond the scope of this email list (i.e. it is a science question, not necessarily a software question), but there is a chance that someone on this list knows the answer.

Best,

Steven 

——————————————————————————————————

Steven DeCaluwe, PhD

Assistant Professor of Mechanical Engineering

Colorado School of Mines

Brown Building W410B

Golden, CO 80401

email: ...@mines.edu