Particle-scale apparent reaction rate

We firstconducted a preliminary kinetic study in order to determine the intrinsic and particle scale apparent reaction rates. A powder catalyst was used to determine the intrinsic reaction rate while cylindrical particles were used both for the parti-... 

The particle scale apparent reaction rate has been determined in a discontinuous Carberry type reactor and in a continuous micro-trickle bed reactor in which catalyst particles... 

C L and CH represent the dissolved hydrogen concentrations at the gas-liquid (saturation) and liquid-solid interfaces, respectively. The analytical expression of the particle scale apparent reaction rate r as a function of has... 

Microkinetics concerns the chemical and physical kinetics at the scale of the particles (catalyst particles, liquid films and droplets, gas bubbles...) and their coupling in order to get the apparent reaction rate and selectivity equations. Macrokinetics refers to the transport of momentiam, mass and heat at the scale of the reactor, and its goal is the establishment of a model of the reactor. Combination of this model with the apparent reaction rate and selectivity equations allows to write the equations of the reactor. 

The products undergo similar mass transfer steps. In principle, heat transfer steps are also to be considered, but generally, temperature gradients are negligible at the particle scale due to the small dimensions of the particle and the great heat capacity of the liquid. The coupling of these different physical and chemical kinetic processes will allow the construction of the apparent reaction rate and selectivity equations. 

P-particles. The reaction appears to take place at the solid surface and is so rapid, that its rate is completely determine by the rate of mass transfer of A to the particles (B is used in excess). TTie mean particle size is 0.1 mm, the solid has an apparent density of 900 kg/m. The minimum fluidization velocity is 0.007 m/s. In a bench scale fluid bed reactor, equippped with a porous distributor plate, and with a bed height of 0.25 m, the conversion of reactant A is measured for various gas flow rates. When these are 0.01, 0.02 and 0.04 the degrees of conversion are, respectively, 0.91, 0.89 and 0.80. For the interpretation of these results we may use Van Swaaij s "simple model", that is shown in the Appendix to section 4.5.1. We find with eq. (4A.1) that the experimental results can be fitted as follows ... 

---