Regeneration in a Technical Fixed Bed Reactor

To model the coke burn-off in an adiabatic technical fixed bed reactor a so-called one dimensional pseudo-homogeneous reactor model (Section 4.10.7.1) was 

and radial gradients of velocity, temperature, residence time, and concentration are neglibible. 

Based on the aforementioned assumptions, the differential equations for the mass and heat balance of the solid and the gas phase (for the parameters see Table 6.9.3) are  

Equations (6.9.25)-(6.9.27) were solved by the above-mentioned computer program Presto for the following boundary conditions at z=0 (reactor inlet)  

The effective dispersion coefficients of heat and mass (Xax, Dax) te calculated by the Pedet numbers [Pem,ax= Wsdp/(eDax), P h.ax = WsCpPmoidp/kax]- Both numbers are approximately 2 (Section 4.10.6.4). Correlations that also consider the static contribution are (VDI, 2002)  

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