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    This webtool is a spreadsheet for selecting proper conditions in a gas-solid fixed-bed reactor for intrinsic reaction kinetics.
    It was developed by the Eurokin consortium ( and made accessible to the public for free in 2012.
    It consists of this spreadsheet and a document with background informationEUROKIN_fixed-bed_html_guide.pdf.
    It requires the physical properties of the components and calculates the heat- and mass transfer coefficients according to correlations from literature.
    The obtained values are substituted into several criteria which indicate if the resistance becomes limiting.
    The red numbers within brackets refer to the corresponding section in the background document 'EUROKIN_fixed-bed_html_guide'.
    The blue numbers should be inserted by the user; the current values correspond to an example on N2O decomposition.
    Disclaimer: This spreadsheet and its functionality have not been tested exhaustively and represent a beta-version. The use of the spreadsheet
    is at the user’s own risk. Under no circumstances, the Eurokin consortium will be liable for any damages (including, without limitation, conse-
    quential, incidental or special damages, including lost profits or lost savings), or for illegal acts or actions, arising from the use of the spreadsheet.
    Also the copyright holders expressly excludes liability for consequential loss or damage which may arise in respect of this spreadsheet,
    its use, the system or in respect of other equipment or property for loss of profit, business revenue, goodwill or anticipated savings.
    Regardless of whether any remedy fails of its essential purpose, in no event will the copyright holders be liable for incidental, indirect,
    special or consequential damages, notwithstanding being aware of the possibility of such damages.
    Print button: Push the print button for printing; this webpage is printer-friendly on A4 paper (4 pages) when choosing landscape format.
    Reset button: Push the reset button to get back all the default values (the buttons are located at the bottom).
    Reaction (1)
    Mol. weight
    Diffus. volume
    Feed composition (mol %) Name [mol-%]
    stoichiometry [kg/mol]
    [m3/mol] (15)
    Limiting reactant (= "A")
    Second compound
    Third compound
    Dilution (or 4th compound)
    Mixture value :
    Reaction conditions:
    Catalyst temperature
    Calculated values
    Total pressure
    Volumetric flow at reaction cond.
    Total molar inlet flow
    Volumetric flow at STP
    Superficial velocity
    Properties of catalyst and dilution
    Particle Reynolds number
    Amount of catalyst
    Density mixture
    Amount of bed dilution
    Molar volume
    Catalyst pellet diameter
    Bed porosity
    Cat. internal specific area
    Space time [Wcat/(mol-A/s)]
    [kg/s mol]    
    Catalyst pellet porosity
    Weight dilution degree
    Catalyst bulk density
    Volume dilution degree
    Catalyst pellet tortuosity
    Bed cross-sectional area
    Cat. pellet thermal conduct.
    Bed height
    Dilution pellet density
    Real residence time in bed
    Dil. pellet thermal conductivity
    Total catalyst bed volume
    Catalyst pellet density
    Reactor dimensions:
    Internal reactor diameter
    Average pore radius
    Diameter thermowell
    Catalyst solid density
    Catalyst pore volume
    Reaction rate
    Average pellets thermal cond.
    [W/m K]
    Observed reaction rate
    Reaction order A
    Observed rate constant
    Apparent activation energy
    Reaction rate per pellet volume
    [mol-A/mpellet3 s]  
    Reaction enthalpy
    Conversion of A
      Physical properties of the components            
    General physical properties (mixture values)
    Calculation of Diffusion coefficient
    Heat capacity [J/mol K]
    Viscosity [kg/m s]
    Thermal conductivity [W/m K]
    (The user should adapt these values accordingly)
      Results concerning transport limitations and other disturbing phenomena      
    Pressure drop over the catalyst bed
    Conditions for allowing assumption ideal plug flow behaviour
    Friction factor
    Axial dispersion
      Pressure drop over the bed [Pa]     Bo (=Pep) [-]    
    DP/P ratio ; must be < (0.2/n) =
    Constant in criterion
              hbed /dp (minimum required)      
                  hbed /dp (experimental)      
    Conditions for the maximum bed dilution
    Relative deviation (D)
    Maximum allowed b [vol-dil/vol-tot]
    Radial dispersion
      Experimental b      
    Criterion: dt /dp should be at least
              dt /dp      
    External mass transport limitation
    Sh [-]
    Internal diffusion limitation
      Mass transfer coefficient (kg) [m3/m2s]     [m2/s]    
    av = 6/dp
    [m2/m3-pellet]     Weisz modulus (F) ; must be <  
    Approximate Thiele modulus (f) [-]
    Ca ; must be < 0.05/n
    tanh (3f) [-]
    Efficiency (for n = 1)
    Approximated efficiency (h) [-]
    Radial heat transfer limitation
      Perf [-]     External heat transport limitation
      ler,0/lG [-]       Nu [-]    
      ler,conv/lG       Note that Nu may get as low as 0.1 at Re <1 in case of channeling !  
      ler [W/mK]     Heat transfer coefficient ap = hw [W/m2 K]    
    Pr (air, 80oC)
    | DT(film) | [K]; must be <
      aw,0 [W/m2 K]            
      aw,conv [W/m2 K]                
      aw [W/m2 K]     Temperature gradient within the pellet
    | DT(rad) | [K]; must be <
    The effect of the internal temperature gradient on the net
    production rate is smaller than 5% if :
    If the temperature of the wall is measured instead of the tem-
    | DT(int) | [K]; must be <
    perature at the central bed axis, another criterion applies:
    | DT(rad) |
    [K]; must be <
    [-]     Adiabatic temperature rise (DTad)
    (13) (14)
    DT(ad) [K]
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