Novel kinetic reactor

Figure 1 Schematic diagram of the novel kinetic reactor (Mehrotra et al., 2003).

Springmaim, S., Friedrich, G Himmen, M Sommer, M. and Eigenberger, G. (2002) Isothermal kinetic measurements for hydrogen production from hydrocarbon fuels using a novel kinetic reactor concept Appl. Catal. A, 235, 101-111. 

H. Ibrahim and H. de Lasa, Novel photocatalytic reactor for the destruction of airborne pollutants reaction kinetics and quantum yields, Ind. Eng. Chem. Res. 38, 3211-3217 (1999). 

Biphasic hydroformylation is a typical and complicated gas-liquid-liquid reaction. Although extensive studies on catalysts, ligands, and catalytic product distributions have appeared, the reaction mechanism has not been understood sufficiently and even contradictory concepts of the site of hydroformylation reaction were developed [11, 13, 20]. Studies on the kinetics of hydroformylation of olefins are not only instructive for improvement of the catalytic complexes and ligands but also provide the basic information for design and scale-up of novel commercial reactors. The kinetics of hydroformylation of different olefins, such as ethylene, propylene, 1-hexene, 1-octene, and 1-dodecene, using homogeneous or supported catalysts has been reported in the literature. However, the results on the kinetics of hydroformylation in aqueous biphasic systems are rather limited and up to now no universally accepted intrinsic biphasic kinetic model has been derived, because of the unelucidated reaction mechanism and complicated effects of multiphase mass transfer (see also Section 2.4.1.1.2). 

Thus, at the operational speed of 7875 RPM, the catalyst was intensively fluidized and gas was completely well mixed in the range of reaction times (1-10 seconds) expected for novel downflow reactors or riser units. In summary, this study proves the excellent ability of the Riser Simulator for catalyst testing and kinetic modelling of catalytic reactions to be conducted under short contact times. 

Many elements of a mathematical model of the catalytic converter are available in the classical chemical reactor engineering literature. There are also many novel features in the automotive catalytic converter that need further analysis or even new formulations the transient analysis of catalytic beds, the shallow pellet bed, the monolith and the stacked and rolled screens, the negative order kinetics of CO oxidation over platinum,... 

Methane can be oxidatively coupled to ethylene with very high yield using the novel gas recycle electrocatalytic or catalytic reactor separator. The ethylene yield is up to 85% for batch operation and up to 50% for continuous flow operation. These promising results, which stem from the novel reactor design and from the adsorptive properties of the molecular sieve material, can be rationalized in terms of a simple macroscopic kinetic model. Such simplified models may be useful for scale up purposes. For practical applications it would be desirable to reduce the recycle ratio p to lower values (e.g. 5-8). This requires a single-pass C2 yield of the order of 15-20%. The Sr-doped La203... 

The field of chemical kinetics and reaction engineering has grown over the years. New experimental techniques have been developed to follow the progress of chemical reactions and these have aided study of the fundamentals and mechanisms of chemical reactions. The availability of personal computers has enhanced the simulation of complex chemical reactions and reactor stability analysis. These activities have resulted in improved designs of industrial reactors. An increased number of industrial patents now relate to new catalysts and catalytic processes, synthetic polymers, and novel reactor designs. Lin [1] has given a comprehensive review of chemical reactions involving kinetics and mechanisms. 

Process Technology. In commercial addition and condensation polymerization processes reactor design is an important factor for the quality and economics of the polymer. Combining macromolecular kinetics with reactor and process design has led to a new concept called reaction engineering. D. C. Chappelear and R. H. M. Simon review this novel concept in Chapter 1. 

The novel cup-and-cap reactor allows kinetic determination of small catalyst loadings, accurate control, and stability of process operating condi-... 

Slurry reactors are often used for intrinsic kinetic measurements. In order to alleviate the effects and complications of the initial heat-up period, as well as the induction period, on the kinetic measurements, novel designs have been introduced. Cup-and-cap reactors, falling-basket reactors, rapid-injection reactors, reactors with induction heaters, and microreactors are five such novel designs. Each of these reactors has been found to be successful the first three, however, consider both induction and heat-up periods. The last two reactors alleviate the complications due to the heat-up period only. All of these... 

P.C. Borman et. al. A novel reactor for determination of kinetics for solid catalyzed gas reactions, AIChE Journal, (1994) 40, 862-869. Reproduced with permission of the American Institute of Chemical Engineers. Copyright 1994 AIChE. All rights reserved. 

The mechanism of particle formation at submicellar surfactant concentrations was established several years ago. New insight was gained into how the structure of surfactants influences the outcome of the reaction. The gap between suspension and emulsion polymerization was bridged. The mode of popularly used redox catalysts was clarified, and completely novel catalyst systems were developed. For non-styrene-like monomers, such as vinyl chloride and vinyl acetate, the kinetic picture was elucidated. Advances were made in determining the mechanism of copolymerization, in particular the effects of water-soluble monomers and of difunctional monomers. The reaction mechanism in flow-through reactors became as well understood as in batch reactors. Computer techniques clarified complex mechanisms. The study of emulsion polymerization in nonaqueous media opened new vistas. 

Large pilot plants remain indispensible only when in the development of an unconventional process sufficient amounts of novel product have to be made available for application studies, or when complex interactions between elements of the process have to be studied in an integrated way. In the latter case, a pilot plant will be a scaled-down version of an actual complex industrial plant, rather than just a reactor unit as required in catalyst performance testing or kinetic process studies. 

ABSTRACT A novel reactor configuration has been developed in our laboratory which addresses the heat transfer limitations usually encountered in vacuum pyrolysis technology. In order to scale-up this reactor to an industrial scale, a systematic study on the heat transfer, the chemical reactions and the movement of the bed of particles inside the reactor has been carried out over the last ten years. Two different configurations of moving and stirred bed pilot units have been used to scale-up a continuous feed vacuum pyrolysis reactor, in accordance with the principle of similarity. A dynamic model for the reactor scale-up was developed, which includes heat transfer, chemical kinetics and particle flow mechanisms. Based on the results of the experimental and theoretical studies, an industrial vacuum pyrolysis reactor, 14.6 m long and 2.2 m in diameter, has been constructed and operated. The operation of the pyrolysis reactor has been successful, with the reactor capacity reaching the predicted feed rate of 3000 kg/h on a biomass feedstock anhydrous basis. 

Novel reactor design with improved mass and heat transfer. Efficient heat transfer facilitates reaction kinetics and decreases energy consumption. As such, reactor size and cost can be significantly reduced. 

On the basis of the kinetics of the biocatalysts and the foregoing decisions, the reactor configuration must then be chosen standard or novel Here, availability, experience, desired mixing, and mass-transfer properties play a dominant role. The mode of operation of the bioreactor can be (fed-)batch or continuous. In making this decision, the kinetics, stability and form of the biocatalyst, desired substrate conversion and product concentration, and need for process control all play a role. 

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