Integral reactor advantages

Now the rate expression for the reaction A —> B together with (26) indicates that the deactivation depends on the composition of the reaction mixture and may vary along the length of the reactor. Under integral reactor conditions this leads to a nonuniform catalyst deactivation in a packed bed. So differential conditions are to be preferred to study this phenomenon. Various empirical activity functions have been proposed [15] whereby using Oc = f(t) instead of = /(cc) has the advantage of being independent of... 

Combines advantages of both differential and integral reactors. The integral recycle rate can be accurately measured and controlled. 

Continuously operated, fixed bed reactors are frequently used for kinetic measurements. Here the reactor is usually a cylindrical tube filled with catalyst particles. Feed of a known composition passes though the catalyst bed at a measured, constant flow rate. The temperature of the reactor wall is usually kept constant to facilitate an isothermal reactor operation. The main advantage of this reactor type is the wealth of experience with their operation and description. If heat and mass transfer resistances cannot be eliminated, they can usually be evaluated more accurately for packed bed reactors than for other reactor types. The reactor may be operated either at very low conversions as a differential reactor or at higher conversions as an integral reactor. 

One advantage of the integral reactor is its ease of construction (see Figure 5-14). On ie other hand, while channeling or bypassing of some of the catalyst by the reactant stream may not be as fatal to diata interpretation in the case of this reactor as in that of the differential reactor, it may still be a problem. 

The disadvantage of the integral reactor is that it can not be operated isothermally and that the measured overall conversion is generally the result of a complex interplay between transport phenomena and chemical reaction. Hence the integral reactor is mainly used for comparitive catalyst studies and lifetime tests. Its advantages are ... 

Integral reactor has the following advantages It is very similar with industrial reactor it is convenient to get the visual results of the evaluation data for some reactions due to high conversion, the accuracy requirements on analysis are not particularly high. Because of the large thermal effect, it is hard to maintain the temperature uniform and constant in whole bed, especially for some strong exothermic... 

In order to see how these advantages could be realized in practice, the performance of a loop reactor was compared with that of a conventionally-built integral reactor.In this comparison the capability to handle actual industrial catalysts, the settling time of changing experimental conditions, the difficulty of the mathematical evaluation of the measured data were considered. The accuracy of the datas for scale up problems was checked in a pilot plant. For the reaction, the oxidation of o-xylene with a vanadiumpentoxide catalyst, an industrially important process, was chosen. 

Ho wever, certain advantages and disadvantages result from the different concentration and temperature distribution in both reactors. Because of the uniformi concentration and temperature inside the loop reactor, the concentration of the reactants could be measured only in the reactor inlet and outlet to determine the reaction rate. The steep concentration and temperature gradients inside the integral reactor require measurements at many spots along the tube. This becomes rather expensive in time if several components are to be analyzed as in the oxidation of xylene. 

The integral reactor shows some advantages in the study of the product quality and selectivity because technical conditions can easily be incorporated. Furthermore, it is possible to measure simultaneously the heat conductivity in the catalyst bed and the heat transfer coefficient through the reactor wall. 

For catalyst testing, conventional small tubular reactors are commonly employed today [2]. However, although the reactors are small, this is not the case for their environment. Large panels of complex fluidic handling manifolds, containment vessels, and extended analytical equipment encompass the tube reactors. Detection is often the bottleneck, since it is still performed in a serial fashion. To overcome this situation, there is the vision, ultimately, to develop PC-card-sized chip systems with integrated microfluidic, sensor, control, and reaction components [2]. The advantages are less space, reduced waste, and fewer utilities. 

One of the most important advantages of the bio-based processes is operation under mild conditions however, this also poses a problem for its integration into conventional refining processes. Another issue is raised by the water solubility of the biocatalysts and the biocatalyst miscibility in oil. The development of new reactor designs, product or by-product recovery schemes and oil-water separation systems is, therefore, quite important in enabling commercialization. Emulsification is thus a necessary step in the process however, it should be noted that highly emulsified oil can pose significant downstream separation problems. 

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