Continuous Reactor Numerical Simulations

When the basic system was operated as a continuous packed bed reactor, the analytical model developed here allows us to describe the performance of all types of reactors, from a continuous stirred tank reactor (CSTR) to a plug flow reactor (PFR). It was shown that the information-processing function depends on the reactor type, the flow rate through the reactor, the concentration of the cofactor in the feed stream, the values of Vm,i, the presence of internal inhibitors, and the cycle time of the input signal. 

The information-processing function carried out in continuous reactors produces the following signals  

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In this chapter the simulation examples are described. As seen from the Table of Contents, the examples are organised according to twelve application areas Batch Reactors, Continuous Tank Reactors, Tubular Reactors, Semi-Continuous Reactors, Mixing Models, Tank Flow Examples, Process Control, Mass Transfer Processes, Distillation Processes, Heat Transfer, and Dynamic Numerical Examples. There are aspects of some examples which relate them to more than one application area, which is usually apparent from the titles of the examples. Within each section, the examples are listed in order of their degree of difficulty. 

Arrojo, P., C. Dopazo, L. Valino, and W. P. Jones (1988). Numerical simulation of velocity and concentration fields in a continuous flow reactor. Chemical Engineering Science 43, 1935-1940. 

This controller was applied to a methylmethacrylate (MMA) solution ho-mopol nnerization conducted in a continuous stirred tank reactor. The solvent and initiator are ethyl acetate and benzoyl peroxide, respectively. The polymerization system parameters for numerical simulations have been taken... 

Table 4.1 Numerical Values of the Operational Parameters Used in Simulations of Fed-Batch and Continuous Reactors...

In Section 4.1.4.1 results of numerical simulations were presented for the case when the basic system is operated as a fed-batch reactor. In this section, results of the numerical simulations are presented for the case when the basic system is operated in continuous reactors. The results were obtained for several reactor types. In terms of compartmental analysis (see Section 4.1.3.2) these types are determined by the number of compartments (n) considered to make up the reactor (see Figure 4.3). Three cases are presented here n = ... 

In this section, results of numerical simulations are presented for the case when the extended basic system is operated in a continuous reactor. Here, the inhibitor enters the reactor as a component of the feed stream and affects the enzyme Ei (it is competitive with Si). In Figures 4.72 to 4.77 the effects of the system parameters on the concentration of B in a PFR with an external inhibitor are presented. The sets of the basic values used for the parameters involved are given in Table 4.12, set I. 

The construction and operation of a continuous rotating annular chromatographic reactor are described. Experimental data for the dehydration of cyclohexane over a Pt/Al Oj catalyst are presented, and the performance of the apparatus as a combined reactor-separator is discussed. A mathematical model is developed, and the results of numerical simulation of reactor performance are presented. 

This paper describes the development and operation of a continuous rotating annular chromatographic reactor (CRACR) for gas-solid reaction systems at elevated temperatures. Experimental and numerical simulation results for the dehydrogenation of cyclohexane on a Pt/Al2C>3 catalyst are presented. 

For ease of fabrication and modular construction, tubular reactors are widely used in continuous processes in the chemical processing industry. Therefore, shell-and-tube membrane reactors will be adopted as the basic model geometry in this chapter. In real production situations, however, more complex geometries and flow configurations are encountered which may require three-dimensional numerical simulation of the complicated physicochemical hydrodynamics. With the advent of more powerful computers and more efficient computational fluid dynamics (CFD) codes, the solution to these complicated problems starts to become feasible. This is particularly true in view of the ongoing intensified interest in parallel computing as applied to CFD. 

Numerical simulations and analyses were performed for both the continuous stirred-tank reactor (CSTR) and the plug-flow reactor (PER). A comparison between the microkinetic model predictions for an isothermal PFR and the experimental results [13], is presented in Fig. 2 for the following conditions commercial low temperature shift Cu catalyst loading of 0.14 g/cm total feed flow rate of 236 cm (STP) min residence time r = 1.8 s feed composition of H20(10%), CO(10%), C02(0%), H2(0%) and N2(balance). As can be seen, the model can satisfactorily reproduce the main features of the WGSR on Cu LTS catalyst without any further fine-tuning, e.g., coverage dependence of the activation energy, etc, which is remarkable and provides proof of the adequacy of the... 

An additional elementary step must be added to equations (1) - (4) and (6) to account for the surface reaction of the 1-butene. Numerical simulations with an elementary step modeling approach discussed elsewhere, Cutlip (Jl ), have confirmed limit cycles for this group of elementary steps when combined with dynamic material balance equations for the reactor. We are continuing experimental and modeling investigations on these interesting phenomena. 

Knowledge of these types of reactors is important because some industrial reactors approach the idealized types or may be simulated by a number of ideal reactors. In this chapter, we will review the above reactors and their applications in the chemical process industries. Additionally, multiphase reactors such as the fixed and fluidized beds are reviewed. In Chapter 5, the numerical method of analysis will be used to model the concentration-time profiles of various reactions in a batch reactor, and provide sizing of the batch, semi-batch, continuous flow stirred tank, and plug flow reactors for both isothermal and adiabatic conditions. 

The numerical calculation based on the thermodynamic and kinetic data can be used to simulate and to compare different reactors, namely, a batch reactor and a continuous fixed bed reactor. 

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