Catalyst wetting experimental values

The value of Z/dv used in the experiments is 188.98, and thus the plug-flow assumption is valid in the whole region of working residence time. Furthermore, from the point of view of catalyst wetting, it is clear that the appropriate experimental point that we can use is the one of 60 s space-time where x = 0.44 and fw = 1. Then, from eq. (5.351),... 

Tables 1.8 and 1.9 illustrate the physical properties for selected formulations at TPR times of 130 and 150 seconds. Control physical properties were not evaluated at these extended TPR times since the control formulations I and V had visual surface distortions and severe scalloping. The data in Tables 1.8 and 1.9 demonstrate that the TPR window can be extended by using these newly developed additives without negative impact to the physical properties. In fact, the data indicates that several of the physical properties for the experimental formulations exceed the control formulation properties at the 90 second TPR time. For example, airflow measurements are improved when utilising the extended TPR times. Improvements are greater than 10% with the Dabco BL-53 catalyst and experimental silicone surfactant combinations. Additional improvements are also observed with wet set and 50% humid aged compression set values.

Die difference from the real value (lm) is mainly due to the approximation made about the mass transfer coefficient as well as the complete wetting of the catalyst, as the actual wetting efficiency is 88%. Furthermore, the problem is more complicated because under incomplete wetting, the gas reactant reaches the catalyst surface more easily than the unwetted part, as Horowitz et al. found out experimentally. 

Hanika et al. (2003) investigated the esterification of acetic acid and butanol in a trickle bed reactor, packed with a strong acid ion- exchange resin (Purolite 151) at 343 K - 393 K. Experimental data illustrate the benefit of simultaneous esterification and partial evaporation of the reaction products in the multi-functional trickle bed reactor. In case of total wetting of the catalyst bed, contact of vaporized products (ester and water) with catalyst was naturally limited and thus, the backward reaction i.e. ester hydrolysis was suppressed. This phenomenon shifted the chemical equilibrium conversion to high values. Saletan (1952) obtained quantitative reaction rate data for the formation of ethyl acetate from ethanol and acetic acid in fixed beds of cation exchange resin catalyst. The complex interaction of diffusion and reaction kinetics within the resin, which determine over-all esterification rate, has been resolved mathematically. 

The catalyst used (Amberlyst 15 - wet resin) acted also as water-absorbing resin. Experimental results were well predicted by a mathematical model developed by the authors, leading to an ethyl lactate productivity value of 31.7 kggL/Lresin day, 95% of purity and a lactic acid conversion of 100%, under optimal conditions. 

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