Reactor Model Development

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. 

The next level of sophistication is to use the nonideal reactor models developed in this chapter. These are fairly simple to calculate, and the results tell us how serious these nonideaUties might be. 

Prengle Jr HW, Symons JM, Belhateche D (1996) H202/VisUV Process for Photo-Oxidation of Waterborne Hazardous Substances - C1-C5 Ghlorinated Hydrocarbons, Waste Management 16, No. 4 327-333. Puma GL, Yue PL (2001) A Novel Fountain Photocatalytic Reactor Model Development and Experimental Validation, Chem. Eng. Sci. 56 2733-2744. 

The reactor models developed for fixed-bed reactors have been exploited for use in other situations, for example, CVD reactors (see Vignette 6.4.2) for microelectronics fabrication. These models are applicable to reaction systems involving single fluid phases and nonmoving solids. There are numerous reaction systems that involve more than one fluid phase. Figure 10.4.3 illustrates various types of reactors... 

The variation in predicted weight percentage of various products as a function of overall conversion agreed well with the published experimental data. The reactor model developed was also able to predict that for an overall conversion of 10% then over 80% of the surface of the catalyst would be covered with adsorbed Cf, olefin carbenium ion). However, once sufficiently high quantities of product olefins had been formed, the model predicted that the surface would become dominated by product olefins because of their relatively high adsorption equilibrium constants compared to that of the paraffinic feed. 

The two-dimensional reactor model developed by the authors is based on mass, energy and momentum balances. It allows axial and radial concentrations and temperature profiles to be evaluated under various effects, such as gas mixture residence time and pressure, and steam-to-carbon ratio. The model allows the plant performance to be evaluated in terms of hydrogen produced and separated and of electric power produced by the residual molten salt sensible heat. 

The mathematical model was constracted on the basis of a three-phase plug-flow reactor model developed by Korsten and Hoffmaim [63]. The model incorporates mass transport at the gas-liquid and liquid-solid interfaces and uses correlations to estimate mass-transfer coefficients and fluid properties at process conditions. The feedstock and products are represented by six chemical lumps (S, N, Ni, V, asphaltenes (Asph), and 538°C-r VR), defined by the overall elemental and physical analyses. Thus, the model accounts for the corresponding reactions HDS, HDN, HDM (nickel (HDNi) and vanadium (HDV) removals), HD As, and HCR of VR. The gas phase is considered to be constituted of hydrogen, hydrogen sulfide, and the cracking product (CH4). The reaction term in the mass balance equations is described by apparent kinetic expressions. The reactor model equations were built under the following assumptions ... 

Figure 4 Flow diagram of reactor model developments. 

Cichy, P.T., J.S. Ultman and T.W.F. Russel. Two-Phase Reactor Design Tubular Reactors - Reactor Model Development 61 (1969) (No. 8) 6-26. 

We describe the generalized step-by-step instruction of the reactor model development in Section 6.4.1. However, the procedures are not applicable to the process with an unusual process flow diagram, such as the HP HCR process, which includes two parallel reactor series. The two parallel reactor series that shares one fractionation unit makes it unachievable to distinguish the production data from one series to the other. For example, there is no way to split the heavy naphtha product into two streams to represent the performance of each reactor series. In addition, it is difficult to start with building the model of two parallel reactor series because model reconciliation of two reactor series is a time-consuming and difficult task. Therefore, we develop the following procedures to build and reconcile HP HCR reactor model ... 

Compared with the reactor model developed in Chapter 6 for hydrotreating of heavy-oil-derived gas oil, the reactor model for hydroprocessing of heavy oil must account for other phenomena that are implicit with the heaviness of the feed, such as... 

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