Laboratory integral reactor

Fig. 8 Laboratory integral reactor for the experimental determination of packing parameters (top left distribution of thermocouples, bottom left detail of probe crossection, right whole reactor...

Figure 4-18. Fixed bed (integral) reactor. (Source V. W. Weekman, Laboratory Reactors and Their Limitations/ A CbEJ, Vol. 20, p. 833, 1974. Used with permission of the AlChEJ.)...

For all likely operating conditions, (ie., for t < X), the appropriate values of the concentration and the polymerization rate constant are the values calculated at t = t ( 2). To prove this, the exit age distribution function for a backmix reactor was used to weight the functions for Cg and kj and the product was integrated over all exit ages (6). It is enlightening at this point to compare equation 18 with one that describes the yield attainable in a typical laboratory semibatch reactor at comparable conditions. ... 

While being shown around Lumphead Laboratories, you stop to view a reactor used to obtain kinetic data. It consists of a 5-cm ID glass column packed with a 30-cm height of active catalyst. Is this a differential or integral reactor ... 

In subsequent stages validation experiments were performed over monolith catalyst samples at two different scales (i) monolith core samples (up to 10 cm3) in a laboratory rig for integral reactor experiments and (ii) full-scale honeycomb monoliths (up to 43 L in size) in engine test bench runs. 

The results Illustrated by Figures 3 and 4 resemble those obtained in the Berty recycle reactor under similar conditions. The space-mean, time average rates for the fixed-bed reactor were only about 50% of those measured in the Berty reactor, because, of course the former reactor achieved conversions high enough for the back reaction to become important. The significance of these observations is that 1) CSTR and differential reactors, widely used for laboratory studies, seem to reflect performance improvements obtainable with fixed-bed, integral reactor which resemble commercial units, and 2) improvement from periodic operation are still observed even tfien reverse reactions become important. 

To be representative of such an industrial reactor, the test reactor has to fulfill the same requirements, i.e., it has to be a close approximation of such an ideal integral reactor as well. Even though commercial reactors may occasionally perform more poorly as a result of improper design, it does not make much sense to try and mimic a malfunctioning commercial reactor on a laboratory scale. 

When multiple reactions are involved, the yield and selectivity are important as well as the conversion. The following example illustrates the method of solving Eq. (4-4) for both single and consecutive reaction systems. The procedure is essentially the reverse of that for interpreting laboratory data on integral reactors (see Sec. 4-3). 

The laboratory study of Fisher and Smith on methane and sulfur vapor reaction illustrates typical apparatus and procedures for differential and integral tubular-flow reactors. An example of a laboratory differential reactor for a homogeneous catalytic reaction has been given by Matsuura et al. ... 

Integral reactor measurements. For integral reactor measurements either engine test units or laboratory equipment with model gas mixtures were used. Both are described in (ref. 1). 

There are two main types of laboratory tests used to get kinetic data batch or integral reactor studies, and tests in a differential reactor. Batch tests are discussed first, since they are more common and often more difficult to interpret. Differential reactors are used primarily for reactions over solid catalysts, which are discussed in Chapter 2. 

Thus, benzaldehyde hydrogenation was tested imder practice-relevant conditions in a catalyst test reactor of simple design, and parameter smdies were carried out. The construction of the laboratory plant is shown schematically in Figure 13-17. Since we are dealing with an integral reactor, in spite of the relatively small amount of catalyst in the trickle-bed reactor, only comparitive measurements were carried out. Continuous hydrogenation of benzaldehyde in the solvents hexane and isopropanol ... 

However, laboratory scale reactor performance and assessments by mathematical models simulations have shown the real and excellent potentiality of membrane integration in chemical processes, leading to a strong increase of reactant conversion at lower operating temperatures. Table 11.1 summarizes the main outcomes reported in Chaps. 5, 6, 7, 8, and 9), where some interesting case studies have been presented and described. 

EP.8 The dehydrogenation of ethanol was conducted in an integral reactor at 275°C. The following experimental data were obtained in the laboratory. 

The intrinsic rate is measured in the laboratory with small catalyst particles, which do not exhibit any diffusion limitations. For a given catalyst, integral reactor tests provide enough information to determine the temperature-dependent coefficients in the intrinsic rate equation. However, since diffusion-free small catalyst particles cannot be used in large reformers because of excessive pressure drop considerations, the impact of diffusion limitations on industrial catalysts must be taken into accovmt as well ... 

Comparing the two laboratory reactors it may be noticed that the loop reactor is more expensive. Although the quantity,.of catalyst and the volume of the loop reactor is small, compared to the integral reactor, the recycling of a large volume of gas requires a complicated blower. 

Laboratory catalytic reactors include many types pulse, batch, tubular (differential and integral), CSTR, recycle, and transport. Figure 8.1 is an illustration of this group. The details of CSTR are given in Figure 8.2. 

FIGURE 8.1 Types of laboratory catalytic reactors (a) pulse, (b) differential, (c) integral, (d) CSTR, (e) recycle, and (f) transport. 

C. E. TiU, The Riquid-Metal Reactor. Overview of the Integrated Fast Reactor Rationale and Basis for Its Development, Presented to National Academy Sciences Committee on Future Nuclear Power, Argonne National Laboratory, Chicago, lU., Aug. 1989. 

Summarizing, the output of the reactor is an integral over time and over the entire reaction space with all interconnections between different zones of the reactor. Mixing and heat- and mass-transfer conditions are usually different in various zones and the pattern of these differences as well as proportions between size of zones vary with scale. Obviously, the histories of concentrations and temperatures in the zones differ. Whether the integral outputs of laboratory and full-scale reactors differ from each other, depends on the sensitivity of the process to mixing and heat- and mass-transfer conditions. If the sensitivity is low only minor... 

Equation 8.3.4 may also be used in the analysis of kinetic data taken in laboratory scale stirred tank reactors. One may directly determine the reaction rate from a knowledge of the reactor volume, flow rate through the reactor, and stream compositions. The fact that one may determine the rate directly and without integration makes stirred tank reactors particularly attractive for use in studies of reactions with complex rate expressions (e.g., enzymatic or heterogeneous catalytic reactions) or of systems in which multiple reactions take place. 

In principle, if the temperatures, velocities, flow patterns, and local rates of mixing of every element of fluid in a reactor were known, and if the differential material and energy balances could be integrated over the reactor volume, one could obtain an exact solution for the composition of the effluent stream and thus the degree of conversion that takes place in the reactor. However, most of this information is lacking for the reactors used in laboratory or commercial practice. Consequently, it has been necessary to develop approximate methods for treating... 

For gas phase heterogeneous catalytic reactions, the continuous-flow integral catalytic reactors with packed catalyst bed have been exclusively used [61-91]. Continuous or short pulsed-radiation (milliseconds) was applied in catalytic studies (see Sect. 10.3.2). To avoid the creation of temperature gradients in the catalyst bed, a single-mode radiation system can be recommended. A typical example of the most advanced laboratory-scale microwave, continuous single-mode catalytic reactor has been described by Roussy et al. [79] and is shown in Figs. 10.4 and... 

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