modelHeteroCatMasstransfer

heterogeneous catalysis including liquid-solid mass transfer

Extends from BaseReaction (partial model for reaction).

Information

This model takes into account reaction. It is possible to have several (independent, parallel or consecutive) reactions, irreversible as well as reversible reactions. A kinetic approach is used, i.e. the equilibrium is not attained at once.

The parameter nR denotes the number of reactions. For each reaction, it has to be stated whether the reaction is reversible or irreversible using the boolean parameter vector reversible. The stocheometric coefficients of the reaction are stored in the parameter nu. The reaction order for forward and reverse reaction is stored in powerCoeffForward and powerCoeffReverse respectively. If no reverse reaction takes place, any values for powerCoeffReverse can be used. The reaction order can not vary during simulation (even though in reality there are reactions where the reaction order changes; often due to a change in temperature). The reaction rate equation is usually written for one component. The number of this component has to be stated in the parameter reacComp.

The reaction rate coefficient of the reverse reaction, k_reverse, is calculated using the reaction rate coefficient of the forward reaction, k_forward, and the equilibrium constant K. The values for k_forward and K are calculated in separate classes which are declared replaceable in this model. The assumption that K is the ratio of k_forward to k_reverse only holds for elementary reactions, not for overall reactions (so it is true for example for A+B <--> C and C+B <--> D but not necessarily for A+2B <--> D).

Example:

  • Medium with 5 substances: A, B, C, D, E
  • reaction 1:
  • A + D <--> C

    r_A = k1_forward * c_D*c_A - k1_reverse * c_C

  • reaction 2:

B--> E

r_B = k2 * c_B^2

Parameters:

  • nR = 2
  • reversible = {true, false}
  • nu = {{-1, 0, 1, -1, 0},{0, -1, 0, 0, 1}}
  • powerCoeffForward = {{1, 0, 0, 1, 0},{0, 2, 0, 0, 0}}
  • powerCoeffReverse = {{0, 0, 1, 0, 0},{0, 0, 0, 0, 0}}
  • reacComp = {1, 2}

Parameters

TypeNameDefaultDescription
Integern (from BaseReaction)
IntegernS (from BaseReaction)MediumLiquid.nSubstancenumber of components, educts=negative, products=positive
Booleanfilm (from BaseReaction)true if reaction reaction model may also be used for film reaction
IntegernRMediumLiquid.nRnumber of reactions
Real[nR,nS]nuMediumLiquid.nustocheometric coefficients for the reaction
Integer[nR]reacCompMediumLiquid.reacCompindex of component in the component vector for which the reaction rate equation is written
SI.Massm_catmass of catalysator in the whole column in Gramm
IntegernSiif sum(abs(MediumLiquid.ic)) == 0 then nS - 1 else nS - 2number of independent composition gradients
Real[nS,nS]k_lfill(1e-4, nS, nS)

Components

TypeNameDefaultDescription
SI.Concentration[nS]c (from BaseReaction)
SI.VolumeV (from BaseReaction)liquid volume
SI.MolarFlowRate[nS]Ndot_l_transfer (from BaseReaction)only needed if no reaction kinetic is taken into account
Real[nS]gamma (from BaseReaction)
SI.MolarFlowRate[nS]Ndot (from BaseReaction)molar flow rate for each substance, positive: substance is created, negative: substance is removed
SI.HeatFlowRatedeltaH_R (from BaseReaction)reaction enthalpy
MediumLiquid.ThermodynamicPropertiespropsLiq (from BaseReaction)
MediumLiquid.ReactionRatesreactionRates
SI.MolarFlowRate[nR,nS]NdotRmolar flow rate for each substance and each reaction
ThermalSeparation.Units.ReactionRate[nR]rm_cat/n*reactionRates.r
MediumLiquid.MolarReactionEnthalpymolarReactionEnthalpy
Units.MolarEnthalpy[nR]h_RmolarReactionEnthalpy.h_Rmolar reaction enthalpy, negative if exotherm
Real[nR]deltaH_singleReac
SI.MoleFraction[nS]x_catmole fraction on catalyst surface
MediumLiquid.ActivityCoefficientactivityCoeffCat
ThermalSeparation.FilmModel.BaseClasses.MaxwellStefanMatrixmaxwellStefanMatrixLiq
Real[nS - 1,nS - 1]RmaxwellStefanMatrixLiq.matrix
Realpot_diff
MediumLiquid.ThermodynamicFactorthermoFactor
MediumLiquid.BasePropertiesmediumLiquidCat
SI.AreaAgeometry.a*geometry.H*geometry.A/ninterfacial liquid-solid area
Geometrygeometry