Tubular reactors with plug flow

In any real situation, reactants only flow through the reactor because there is a difference in pressure between the inlet and the outlet. Methods for calculating the pressure drop in pipes and packed beds have been outlined in Chap. 1. Often, the pressure drop is negligible compared with the total pressure and it is usual to assume that a tubular reactor with plug flow operates at constant pressure. 

The approach to the design of non-isothermal tubular reactors with plug flow parallels that already outlined for batch reactors (see Sect. 2.4.)... 

In Sect. 3.2, the development of the design equation for the tubular reactor with plug flow was based on the assumption that velocity and concentration gradients do not exist in the direction perpendiculeir to fluid flow. In industrial tubular reactors, turbulent flow is usually desirable since it is accompanied by effective heat and mass transfer and when turbulent flow takes place, the deviation from true plug flow is not great. However, especially in dealing with liquids of high viscosity, it may not be possible to achieve turbulent flow with a reasonable pressure drop and laminar flow must then be tolerated. 

As i the term in brackets above tends to exp (vit/V) for t < V/v), and F becomes zero(7>. Thus, for an infinite number of tanks the fraction of tracer that has escaped is zero for all times less than the residence time V/v. This is exactly the same as for the case of an ideal tubular reactor with plug flow. 

Beyne and Froment [1993] simulated a tubular reactor with plug flow and diffiisional limitations inside the catalyst for the process discussed already in Section 3. The main reaction is of the type A B and coke is formed through a polymerization mechanism from a site covered by coke... 

Alternatively, tubular reactors with plug flow (piston flow) (PFR) are used and operated in continuous mode (Figure 1.15). 

De Pauw and Froment [1975] studied n.Cj isomerization on a Pt/alumina catalyst in an isothermal tubular reactor with plug flow, yielding n.Cj-conversion, x, versus W/F °-data. Therefore, the following objective function was chosen for the parameter estimation ... 

The reaction is carried out in an isothermal tubular reactor with plug flow. Accordingly, when the rate equation for the disappearance of A is substituted into the integrated continuity equation for Ai,... 

Fig. 2.2-4 Cumulative residence-time function F t/z) for an ideal continuous stirred tank (1), an ideal tubular reactor with plug flow (2), and laminar flow in a tubular reactor (3).

The experimental study of Froment et al. (loc. cit) was carried out in a tubular reactor with plug flow. Tlie data were obtained as follows total conversion of propane versus a measure of the residence time, lyfF cH.fe conversion of propane into propylene versus 1V(Kcjh,)o reactor volume reduced to... 

It will be shown in Chapter 9 that a mass balance on propane over an isothermal differential volume element of a tubular reactor with plug flow may be written... 

This is the energy equation for a single-phase tubular reactor with plug flow. Note that Eq. 7.1d-4 is coupled with the continuity equation, mainly by the reaction term, but also through the heat capacity term on the left-hand side. The latter is sometimes written in terms of a specific heat that is averaged with respect to temperature and composition, that is, Yj = "c,. 

Example 9.1-1 Derivation of a Kinetic Equation from Experiments in an Isothermal Tubular Reactor with Plug Flow. Thermal Cracking of Propane... 

Design of Tubular Reactors with Plug Flow... 

The process A B C is canied out in a tubular reactor with plug flow. Both reactions are of first order. The feed consists of pure A. Given the following data... 

Calculate the effect of recycle on the conversion in tubular reactors with plug flow. NONIDEAL FLOW PATTERNS AND POPULATION BALANCE MODELS 655... 

The Continuity, Energy, and Momentum Equations Kinetic Studies Using a Tubular Reactor with Plug Flow... 

KINETIC STUDIES USING A TUBULAR REACTOR WITH PLUG FLOW... 

The thermal cracking of propane was studied at atmospheric pressure and 800°C in a tubular reactor with plug flow and operated in the integral mode. The... 

DESIGN AND SIMULATION OF TUBULAR REACTORS WITH PLUG FLOW 439... 

Finally, it should be added that the phenomenon of parametric sensitivity, dealt with in this section, is essentially different from the instability encountered in Chapter 10. The tubular reactor with plug flow without recycle as considered here is intrinsically stable in the strict sense (except if kinetic instability would occur). On removal of the perturbation, the reactor will return to its original state. The hysteresis phenomenon encountered in Chapter 10 is not possible in the present case all intermediate steady states are possible. 

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