Second plug flow reactor

This is the equation for a plug flow reactor. It can be derived directly from the rate equations with the aid of Laplace transforms. The sequences of second-order reactions of Figs. 7-5n and 7-5c required numerical integrations. 

Example 5 Application of Effectiveness For a second-order reaction in a plug flow reactor the Thiele modulus is ( ) = SVQ, and inlet concentration is C50 = 1.0. The equation will he integrated for 80 percent conversion with Simpsons rule. Values of T) are... 

These investigators report that the second-order rate constant for reaction B is equal to 1.15 x 10 3 m3/mole-ksec at 20 °C. Determine the volume of plug flow reactor that would be necessary to achieve 40% conversion of the input butadiene assuming isothermal operating conditions and a liquid feed rate of 0.500 m3/ksec. The feed composition is as follows. 

Comparison of performance of a series of N equal-size CSTR reactors with a plug flow reactor for elementary second-order reactions... 

Comparison of the fractional yields of V in mixed and plug flow reactors for the consecutive first-order reactions. A A- V W. (Adapted from Chemical Reaction Engineering, Second Edition, by O. Levenspiel. Copyright 1972. Reprinted by permission of John Wiley and Sons, Inc.)... 

The F(t) curve for a system consisting of a plug flow reactor followed by a continuous stirred tank reactor is identical to that of a system in which the CSTR precedes the PFR. Show that the overall fraction conversions obtained in these two combinations are different when the reactions are other than first-order. Derive appropriate expressions for the case of second-order irreversible reactions and indicate how the reactors should be ordered so as to maximize the conversion achieved. 

Two Reactions, Different Orders—In the case of a desired second-order reaction and an undesired first-order reaction, such as A + B - C and A — D, where C is the desired product, the batch, semi-batch, or plug-flow reactor is preferred. 

Acetaldehyde vapor was passed through a plug flow reactor at atmospheric pressure and 600 C. The fraction remaining, f - na/na0 was measured as a function of Vr/na0 measured in seconds. 

A C. The second specific rate is known, k2 = 0.5. In a plug flow reactor with an inlet concentration Ca0 = 1.2, a conversion of 65% is obtained with a contact time t = Vp/V = 0.2. Find the other specific rate. 

At present the liquid phase reaction, A + B = C + D, takes place in a plug flow reactor. A conversion of 96% is obtained with Ca0 = Cb0 = 1 mol/liter. A mixed reactor 10 times the volume of the PFR is connected in series. Find conversions with the PFR first and with the PFR second in series. In the PFR,... 

For fairly high degrees of conversion, with both first- and second-order reactions, the volume of a tubular reactor in which laminar flow occurs is about 30—50% greater than that of the plug-flow reactor in... 

As Table 5 shows, the volume of a continuous stirred tank with a certain performance is greater than that of the corresponding plug-flow reactor. The volume ratio with a second-order reaction is markedly greater than when first-order kinetics apply and this effect is greater at high conversions where both ratios can be very large. 

Mixed Versus Plug Flow Reactors, First- and Second-Order Reactions... 

Thus in Fig. 6.1, and in terms of the limiting component A, the size ratio of mixed to plug flow reactors is represented by the region between the first-order and the second-order curves. 

Figure 6.17 Comparison of performance of recycle reactors with plug flow reactors for elementary second-order reactions (Personal communication, from T. J. Fitzgerald and P. Fillesi) ...

An aqueous reactant stream (4 mol A/liter) passes through a mixed flow reactor followed by a plug flow reactor. Find the concentration at the exit of the plug flow reactor if in the mixed flow reactor = 1 mol/liter. The reaction is second-order with respect to A, and the volume of the plug flow unit is three times that of the mixed flow unit. 

At present conversion is 2/3 for our elementary second-order liquid reaction 2A 2R when operating in an isothermal plug flow reactor with a recycle ratio of unity. What will be the conversion if the recycle stream is shut off ... 

Figure 13.20 Comparison of real and plug flow reactors for the second-order reactions...

It is expected that the conclusions reached in the analysis of the series reaction will also be valid for methane partial oxidation. The first objective of this study was to verify this expectation. The second objective of the study was to determine how much faster than methane formaldehyde must permeate for the membrane reactor to begin to outperform a plug-flow reactor. 

The main individual reactions that take place in the reformer (e.g., reactions (1), (2) and (5)) will be considered separately from the overall autothermal reaction for two reasons. First, in ATR the reactor can be considered as two plug-flow reactors in series (1) a very fast POX reaction occurs at the top of the catalyst bed and utilizes a small portion of the bed and (2) a slow SR utilizes the remainder of the reactor bed. Therefore, an optimal ATR catalyst must have excellent SR eatalytic properties. Second, there may be situations in which liquid fuels are reformed using only these individual reactions e.g., diesel fuel may be reformed using only SR (reaction (2)) or only by POX (reaction (1)). 

A plug flow reactor is operated with partial recycle of unconverted material. The reaction is second order liquid phase, 2A => B. Concentration of... 

The same general conclusions apply since backmixing of products with reactants should be avoided, a tubular plug-flow reactor or a batch reactor is preferred. However, there is one respect in which a series reaction involving a second reactant B does differ from simple series reaction with one reactant, even when the orders are the same. This is in the stoichiometry of the reaction the reaction cannot proceed completely to the product Q, even in infinite time, if less than two moles... 

The plug flow reactor is the second primary type of ideal flow reactor. It is also erroneously referred to as a tubular reactor. 

Assuming that the reaction is second order, the design Equation 5-307 for a plug flow reactor is... 

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