Reactor honeycomb

A mathematical model for the design of extruded honeycomb reactor for selective catalytic reduction of NOx... 

A mathematical model to predict the performance of extruded honeycomb reactors has been... 

A material balance at axial position x of the honeycomb reactor over the external gas film... 

The consideration of the pressure drop over the monoliths containing a variety of CPSI (cells per in ) for the modeling of honeycomb reactor may be required, since Ap of the reactor strongly depends on CPSI of monolith. Eqn. (7) for the pressure drop of the honeycomb was employed to develop the reactor model describing the performance of the honeycomb fabricated in the present work [8]. and Ke indicate contraction and expansion loss coefficient at the honeycomb inlet and outlet, respectively and o is the ratio of free flow area to frontal area. 

In Fig. 1, a comparison can be observed for the prediction by the honeycomb reactor model developed with the parameters directly obtained from the kinetic study over the packed-bed flow reactor [6] and from the extruded honeycomb reactor for the 10 and 100 CPSI honeycomb reactors. The model with both parameters well describes the performance of both reactors although the parameters estimated from the honeycomb reactor more closely predict the experiment data than the parameters estimated from the kinetic study over the packed-bed reactor. The model with the parameters from the packed-bed reactor predicts slightly higher conversion of NO and lower emission of NHj as the reaction temperature decreases. The discrepancy also varies with respect to the reactor space velocity. 

The kinetic parameters estimated by the experimental data obtained frmn the honeycomb reactor along with the packed bed flow reactor as listed in Table 1 reveal that all the kinetic parameters estimated from both reactors are similar to each other. This indicates that the honeycomb reactor model developed in the present study can directly employ intrinsic kinetic parameters estimated from the kinetic study over the packed-bed flow reactor. It will significantly reduce the efibrt for predicting the performance of monolith and estimating the parameters for the design of the commercial SCR reactor along with the reaction kinetics. 

Table 1. Kinetic parameters obtained from packed-bed and honeycomb Reactors...

Kinetic parameters Packed-bed reactor Honeycomb reactor... 

Fig. 1. Prediction of the model for 10 and 100 CPSI honeycomb reactors extruded with the ViOs/sulfated Xi02 catalyst. (—, prediction with the parameters estimated from the experimental data over a packed-bed flow reactor —, prediction with the parameters estimated from the experimental data over a honeycomb reactor).

Fig.3. Temperature profiles of the honeycomb reactor. Insulator wall (—and aluminum wall (-).

Figure 13.8 Experimental and simulated evolution of NO outlet concentration during start-up and shut-down of an SCR honeycomb reactor (open circles, a = 0.6 triangles, a —0.8 squares, a= 1) (a) and following step variation of NO inlet concentration (b). Adapted from ref. [46].

Mayer et al. [43] used an electrically heated micro heat exchanger, a micro mixer and a honeycomb reactor, all developed by Karlsruhe Research Center (Forschungs-zentrum Karlsruhe), for the partial oxidation of methane ... 

Figure 14 Start-up and shutdown of an SCR honeycomb reactor Comparison of laboratory data with model predictions of outlet NO concentration C q PP Nm/h, T...

Table 9 Comparison Between Simulated and Experimental Yields of Naphtha/Steam Cracking in Honeycomb Reactor ...

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