Temperature distribution, integral reactor

The total acidity deterioration and the acidity strength distribution of a catalyst prepared from a H-ZSM-5 zeolite has been studied in the MTG process carried out in catalytic chamber and in an isothermal fixed bed integral reactor. The acidity deterioration has been related to coke deposition. The evolution of the acidic structure and of coke deposition has been analysed in situ, by diffuse reflectance FTIR in a catalytic chamber. The effect of operating conditions (time on stream and temperature) on acidity deterioration, coke deposition and coke nature has been studied from experiments in a fixed integral reactor. The technique for studying acidity yields a reproducible measurement of total acidity and acidity strength distribution of the catalyst deactivated by coke. The NH3 adsorption-desorption is measured by combination of scanning differential calorimetry and the FTIR analysis of the products desorbed. 

For such chemical reactors which are characterized by an ideally well mixed reaction volume, therefore allowing the assumption of a uniform temperature distribution, a transfer of this differential heat balance to an integral balance is possible by multiplying it with the volume of the system balanced. This way the general integral heat balance for well mixed reactors is obtained ... 

Good thermal insulation and integration is important in order to minimize heat losses in the reactors. It is best if the catalytic burner is made as part of the reformer (such as in a concentric reformer and burner configuration) in order to maximize the heat utilization produced by the burner and to achieve more even temperature distribution within the reformer. Since the... 

In the study of dynamics, the integral reactor can be divided into two types — isothermal and adiabatic reactor. Because isothermal integral reactor is simple and cheap as well as the lower demand on the accuracy on analysis, it is always the preferred option. In order to overcome its difficulties to maintain the temperature uniform, there are several actions. The first one is to reduce the diameter to obtain uniform radial temperature as much as possible. When the inner diameter of reactor is 4-6 times bigger than the particle size of catalyst, the effect of reducing the diameter of tube on the distribution of temperature still is the main factor. The second is to use various mediums with high thermal conductivity, to provide heating indirectly through the whole piece of metal or sand bath, which is commonly used presently. The third is to dilute the catalyst bed with inert materials. 

The adiabatic integral reactor has the characteristics of uniform diameter, filling with homogeneous catalyst, and good insulation. The feeds preheated to a certain temperature infiood into the reactor, and measure axially the reaction heat and the corresponding temperature distribution of kinetic law. However, the data acquisition and mathematic explanation are difficult for the reactors. 

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. 

Pulses were taken at temperatures between 210 and 450 C at 3(P intervals, and in each case the conversion of methanol and the product distribution were determined. Figure 5 shows a typical result of an experiment. The intensity of various mass nunbers is plotted as a function of time. In this case 660 mg of the comnercial catalyst was in the reactor and twelve masses were scanned at a rate of approximately 200 ms/scan, using the data integrator. In most of the experiments, the scanning rate was faster 80-100 ms/scan for 8-10 masses. 

Continuous Multicomponent Distillation Column 501 Gas Separation by Membrane Permeation 475 Transport of Heavy Metals in Water and Sediment 565 Residence Time Distribution Studies 381 Nitrification in a Fluidised Bed Reactor 547 Conversion of Nitrobenzene to Aniline 329 Non-Ideal Stirred-Tank Reactor 374 Oscillating Tank Reactor Behaviour 290 Oxidation Reaction in an Aerated Tank 250 Classic Streeter-Phelps Oxygen Sag Curves 569 Auto-Refrigerated Reactor 295 Batch Reactor of Luyben 253 Reversible Reaction with Temperature Effects 305 Reversible Reaction with Variable Heat Capacities 299 Reaction with Integrated Extraction of Inhibitory Product 280... 

To evaluate fission product release in a reactor, it is necessary to supply the appropriate particle geometry, diffusion coefficients, and distribution coefficients. This is a formidable task. To approach this problem, postirradiation fission product release has been studied as a function of temperature. The results of these studies are complex and require considerable interpretation. The SLIDER code without a source term has proved to be of considerable value in this interpretation. Parametric studies have been made of the integrated release of fission products, initially wholly in the fueled region, as a function of the diffusion coefficients and the distribution coefficients. These studies have led to observations of critical features in describing integrated fission product releases. From experimental values associated with these critical features, it is possible to evaluate at least partially diffusion coefficients and distribution coefficients. These experimental values may then be put back into SLIDER with appropriate birth and decay rates to evaluate inreactor particle fission product releases. Figure 11 is a representation of SLIDER simulation of a simplified postirradiation fission product release experiment. Calculations have been made with the following pertinent input data ... 

The influence of heat losses through the reactor wall have been studied [5,23]. Radial temperature gradients inside the monolith material can often be neglected, because the operation is usually adiabatic. This means that modeling of one single channel is adequate. Any nonuniform flow distribution may be incorporated into a reactor model by integration of the single channel performance over the whole cross section of the reactor. 

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