Berty-type reactors

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. 

Liquid phase experiments were performed with 5.0 or 10.0 g of catalyst pellets in a 300 ml Berty-type reactor under batch conditions at 66 to 100 °C and 1.0 or 5.0 vol.% n-propyl nitrate. Prior to reaction, the catalyst sample was calcined at 500 °C for 2 hrs. in 0.5 cmVmin of air. Then the catalyst was purged with He for 5 min before the addition of 250-280 ml of preheated toluene. Stirring at 300 rpm, the n-propyl nitrate was added via syringe injection, this point represents time zero. To follow the evolution of activity with reaction holding time, liquid samples of 1 ml were taken with a syringe and mixed with an internal standard of decane, diluted in hexane, as the calibration solution before analysis. Both vapor and liquid reaction... 

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... 

A compromise may be to study industrial-size pellets in internal recycle reactors (Rostrup-Nielsen et al., 1988a), which at a high recycle rate approach a continuously stirred tank reactor (CSTR). The mass velocity in such Berty-type reactors is still one order of magnitude lower than in industrial reformers, and the temperature gradients over the gas film on the catalyst surface are still significant. Hence, it is necessary to measure the catalyst pellet temperature directly by fitting a thin thermocouple well into a drilled hole in one of the pellets. 

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

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. 

Ethylene oxide catalyst research is expensive and time-consuming because of the need to break in and stabilize the catalyst before rehable data can be collected. Computer controlled tubular microreactors containing as Httle as 5 g of catalyst can be used for assessment of a catalyst s initial performance and for long-term life studies, but moving basket reactors of the Berty (77) or Carberry (78) type are much better suited to kinetic studies. 

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. 

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. 

Referring to Figure 3.5.2, the Carberry reactor contains paddles in which the catalyst is mounted and the paddles are rapidly rotated via connection to a control shaft in order to obtain good mixing between the gas phase and the catalyst. A Berty reactor consists of a stationary bed of catalyst that is contacted via circulation of the gas phase by impeller blades. The quality of mixing in this type of configuration... 

Tank reactors for solid-catalyzed gaseous or liquid reactions are seen much less frequently than tubular reactors because of the difficulty in separating the phases and in agitating a fluid phase in the presence of solid particles. One type of CSTR used to study catalytic reactions is the spinning basket reactor, which has the catalyst embedded in the blades of the spinning agitator. Another is the Berty reactor, which uses an internal recycle stream to achieve perfectly mixed behavior." These reactors (see Chapter 5) are frequently used in industry to evaluate reaction mechanisms and determine reaction kinetics. 

Some other types of gradientless reactors with stirred flow are the Berty reactor which circulates gas past a stationary catalyst bed (Figire 1.27)... 

Kinetic rate expressions, which may be obtained from experimental measurements in a Berty reactor or a similar type of reactor. 

The kinetics of methane combustion over a perovskite catalyst (Lao.9Ceo.iCo03) has been studied in Micro-Berty and fixed bed reactors. Discrimination among twenty-three rival kinetic models from Eley-Rideal, LHHW and Mars-van Krevelen (MVK) types has been achieved by means of (a) the initial rate method as well as by (b) integral kinetic data analysis. Two MVK type models could be retained as a result of the two studies, with a steady-state assumption implying the equality of the rate of three elementary steps. 

The catalyst, which was prepared by the citrate method and calcined at 700°C, had a BET surface of 10.2 m /g. The experiments were carried out in two types of reactor, i.e. (a) in a Micro-Berty reactor that has a catalyst basket volume of 3.6 cm, (b) in a fixed bed quartz reactor having an internal diameter of 10mm. Gaseous flows were controlled by mass flow controllers, and the pressure in the Berty reactor was adjusted by a backpressure regulator and measured by a pressure transducer. Experimental conditions are compared in the Table 2. 

The experimental initial rate curves in the Berty reactor (Fig. 2.b) shows a trend that can represent either type b ox e among the theoretical graphs in the Figure 1. Since the model Ml 7 belongs to type c it can be removed in the final selection from likely mechanisms. The two retained models. Ml 8 and M20 both are of Mars-van Krevelen types where the steady-state assumption involves the equality of the rate of three elementary steps as it has been shown in the Table 1. 

Various types of reactors, including those shown in Figure 3.1, have been evaluated by Weekman (1974) and Berty (1979) with respect to the ease of construction, sampling, isothermality, and contact time. These evaluations show that the usual differential and integral reactors are poor devices compared with the other types. The recycle reactor is perhaps the best overall. The transport reactor is quite useful for rapidly decaying catalytic reactions since steady state conditions can be achieved despite catalyst deactivation. 

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