Berty recycle reactor

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. 

It is always best to operate an experimental reactor under conditions where all diffusional disguises are lifted (by using the criteria listed in the previous section). A less acceptable alternative is to account for them through appropriate effectiveness factors and external transport coefficients. A number of highly sophisticated computer-controlled reactor systems such as the Berty recycle reactor are commercially available. Many of them are available with software and appropriate interfacing that can set and implement the experiments for each of a series of sequential runs (see Mandler et al., 1983), resulting in the emergence of the most acceptable model at the end of the exercise. 

Figure 2.3.2 (Kraemer and deLasa 1988) shows this reactor. DeLasa suggested for Riser Simulator a Fluidized Recycle reactor that is essentially an upside down Berty reactor. Kraemer and DeLasa (1988) also described a method to simulate the riser of a fluid catalyst cracking unit in this reactor.

The older internal recycle reactors of Berty et al (1969), and Berty (1974) are shown on Figures 2.4.3 a, b. The reactor of Romer and Luft (1974) uses no mechanical moving parts. The recirculation is generated by the feed gas as it expands through a nozzle. A major disadvantage of using a jet is that feed rate and recirculation rate are not independent. Due to the low efficiency of jet pumps, recycle rates are quite low. 

The operational characteristics of the older Berty reactors are described in Berty (1974), and their use in catalyst testing in Berty (1979). Typical uses for ethylene oxide catalyst testing are described in Bhasin (1980). Internal recycle reactors are easy to run with minimum control or automation. 

Another view is given in Figure 3.1.2 (Berty 1979), to understand the inner workings of recycle reactors. Here the recycle reactor is represented as an ideal, isothermal, plug-flow, tubular reactor with external recycle. This view justifies the frequently used name loop reactor. As is customary for the calculation of performance for tubular reactors, the rate equations are integrated from initial to final conditions within the inner balance limit. This calculation represents an implicit problem since the initial conditions depend on the result because of the recycle stream. Therefore, repeated trial and error calculations are needed for recycle... 

The original recycle reactor developed at Union Carbide Corporation in 1962 (Berty et al 1968) was modified or adapted by several people to different projects. Many recycle reactors were also designed by others for... 

In Chapter 1, Figure 1.4.1 (Berty et al, 1969) shows the actual measurement results of the older 5 diameter recycle reactor performance, using two different types of equipment. 

Of these three, two must be measured experimentally to calculate the stability criteria. In recycle reactors that operate as CSTRs, rates are measured directly. Baloo and Berty (1989) simulated experiments in a CSTR for the measurement of reaction rate derivatives with the UCKRON test problem. To develop the derivatives of the rates, one must measure at somewhat higher and lower values of the argument. From these the calculated finite differences are an approximation of the derivative, e.g. ... 

Figure 5.4-19. Internally recycled reactor (Berty reactor).

Internally recycled reactor (Berty) High temperature, high pressure catalytic processes High transport rates, intense mixing Limited ease of variation of parameters... 

Improvement by cycling was in the range of 30 to 50%. This was almost identical to the improvement achieved in experiments performed in a laboratory recycle reactor. This finding shows that measurements made by our research group and others on differential or Berty-type reactors are a reliable guide to the performance of full-scale equipment. 

The second reactor of the Berty, recycle type is shown in the upper left center of Figure 1. It was also used to explore the effect of periodic operation. 

Internal recycle reactors are designed so that the relative velocity between the catalyst and the fluid phase is increased without increasing the overall feed and outlet flow rates. This facilitates the interphase heat and mass transfer rates. A typical internal flow recycle stirred reactor design proposed by Berty (1974, 1979) is shown in Fig. 18. This type of reactor is ideally suited for laboratory kinetic studies. The reactor, however, works better at higher pressure than at lower pressure. The other types of internal recycle reactors that can be effectively used for gas-liquid-solid reactions are those with a fixed bed of catalyst in a basket placed at the wall or at the center. Brown (1969) showed that imperfect mixing and heat and mass transfer effects are absent above a stirrer speed of about 2,000 rpm. Some important features of internal recycle reactors are listed in Table XII. The information on gas-liquid and liquid-solid mass transfer coefficients in these reactors is rather limited, and more work in this area is necessary. 

Fig. 18. Flow recycle reactor (Berty type). (Berty, 1974 also from Chaudhari el al.. 1986, by courtesy of Marcel Dekker, Inc.)...

Berty J.M. 20 Years of Recycle Reactors in Reaction Engineering Plant/Oper. Prog., 1984, 3, 163-168. 

Zwahlen A. G., Agnew J. Modification of an Internal Recycle Reactor of the Berty Type for Low-Pressure High Temperature Catalytic Gas-Phase Reaction CHEMECA 1987, I, 50.1-50.7, Melbourne, Australia. 

The difficulties inherent to the external recycle reactor are avoided in an internal recycle reactor. Basically, an internal recycle reactor consists of a basket, in which a variable amount of catalyst can be placed, and an impeller for the internal circulation of the gas in the reactor. One of the most popular recycle reactors is the Berty reactor [29] shown in Figure 5.5. The Berty reactor has a magnetically driven blower and the gas from the turbine flows through a draft tube to the top of the catalyst bed. The flow rate through the bed can be calculated by measuring the pressure drop over the bed, if pressure taps on either side of the catalyst are available. For a catalyst to be studied in this reactor, the... 

Many authors have proposed reactors with similar basic principles. The best known are those of Garanin et al. [44], Livbjerg and Villadsen [45] and new versions of Berty reactor [34]. Variants of internal recycling reactors have also been proposed by Bennett et al. [43] who tried to decrease the ratio of reactor volume to catalyst volume. In this arrangement the amount of reactant adsorbed increases compared to that in the gas space as a result the dynamics of the adsorption - desorption processes can be detected through the gas phase measurements. 

The advantages of internal recycle reactors for catalyst investigations have been outlined by Berty [46,47], Like other differential reactors, a single experiment yields the... 

In Section 3.5 recycle reactors and particularly a Berty reactor were described. At high impeller rotation speed, a Berty reactor should behave as a CSTR. Below are plotted the dimensionless exit concentrations, that is, C(t)/C°, of cis-2-butene from a Berty reactor containing alumina catalyst pellets that is operated at 4 atm pressure and 2000 rpm impeller rotation speed at temperatures of 298 K and 427 K. At these temperatures, the cis-2-butene is not isomerized over the catalyst pellets. At t = 0, the feed stream containing 2 vol % cis-2-butene in helium is switched to a stream of pure helium at the same total flow rate. Reaction rates for the isomerization of cis-2-butene into 1-butene and trans-2-butene are to be measured at higher temperatures in this reactor configuration. Can the CSTR material balance be used to ascertain the rate data ... 

Bertucco et al. investigated the effect of SCCO2 on the hydrogenation of unsaturated ketones catalyzed by a supported Pd catalyst, by using a modified intemal-recycle Berty-type reactor [63]. A kinetic model was developed to interpret the experimental results. To apply this model to the multiphase reaction system, the calculation of high-pressure phase equilibria was required. A Peng-Robinson equation of state with mixture parameters tuned by experimental binary data provided a satisfactory interpretation of all binary and ternary vapor-liquid equilibrium data available and was extended to multicomponent... 

PE = polyethylene PP = polypropylene PS = polystyrene ASR = automobile shredder residue VGO = vacuum gas oil LCO = light cycle oil. SA = Si02/ AI2O3 MOR = mordenite. TD/CD = thermal degradation followed by catalytic degradation COMB = mixed polymer and catalyst in a batch reactor COMS = mixed polymer and catalyst in a semibatch reactor FB = fixed bed flow reactor BIRR = Berty internal recycle reactor. 

The reactor used for these studies is the Autoclave Engineer s Berty internally-recycled reactor (19) which is supplied with a 3-kW heater. Temperature control is achieved via a Nanmac Model PC-1 temperature controller which operates a mercury relay switch-variac combination which powers the heaters. 

They found the reaction order for H2 (6) was positive but the reaction order for CO (a) was negative, suggesting inhibition by adsorbed CO. Samp and Wojciechowski [16] compared six different possible mechanisms to FT synthesis data they obtained with a cobalt catalyst used in a Berty internal recycle reactor. They found the best fit was obtained with the expression ... 

J. Berty, Testing commercial catalysts in recycle reactors. Catalysis Reviews Science and Engineering, vol. 20, pp. 75-96, 1979. 

The negative reaction order was confirmed by measurements with industrial-size catalyst pellets in an internal recycle reactor (CSTR, Berty reactor), as shown in Figure 3.27. 

FIGURE A9.7 Configuration alternatives for a gradientless reactor, (a) A stationary catalyst basket (Berty reactor), (b) a rotating catalyst basket (Carberry reactor), and (c) a recycle reactor. 

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