I'm comparing a model with chemistry at equilibrium versus a kinetic one.
I take a network of two reactions: methane steam reforming (MSR) and water gas shift (WGS) at 700°C.

I calculated extent of reaction of both reaction, with the equilibrium hypothesis, solving a system of two non-linear equation containing the two $ K _{eq} (T) =f(\lambda_{MSR}, \lambda_{WGS}) $ equations, which give me these results:

$\lambda_{MSR} = 1.4167e-4 [mol/s]$
$\lambda_{WGS} = -6.6788e-5 [mol/s]$

Then I calculate rates of reaction with an homogeneous and stoichiometric coefficient expression, with Temperature dependence constant (Arrhenius) taken here, I get:

$r _{MSR} = 20.9761e-4 [mol/s/m^3]$
$r _{WGS} = 0.0 [mol/s/m^3]$ (I have no reactants nor products...)

Now to compare them I have to multiply $r$ for reactor's volume.

Here start my doubt:
taking for sake of simplicity $1[m^3]$ reactor, I get


  • this what does it mean?
  • does it have a physical meaning?
  • what is the meaning of a so large reactor?

My thoughts, my idea, is that equilibrium shows the maximum rate of reaction so kinetic should, or better must, respect it giving me a lower value of reaction rate; but, as you can easily see in my above example, this statement (that I have never read somewhere in any chemistry book, so I can take it as truth) can be superimposed, forced. How do you explain it?

  • $\begingroup$ please provide some feedback, I can add some other information if you need it! $\endgroup$ – mattia.b89 Aug 4 '15 at 7:09

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