Criteria for Reactor Selection

The criteria that may be applied for selecting a multiphase reactor for a given application can be summarized as follows  

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Many fine chemistry proces.ses can be lumped into a system of two parallel or two con.secutive reactions. Selectivity can roughly be assessed using the gross kinetics for such lumped schemes, and this can be used to derive approximate criteria for reactor selection. 

This section starts with a classification of phase-contacting principles according to the type of catalytic bed. Advantages and disadvantages of the reactor types are explained, followed by a discussion of criteria for reactor selection and an overview of purchasable microreactors for catalytic gas-phase reactions. 

Hydrothermal Synthesis Systems. Of the unit operations depicted in Figure 1, the pressurized sections from reactor inlet to pressure letdown ate key to hydrothermal process design. In consideration of scale-up of a hydrothermal process for high performance materials, several criteria must be considered. First, the mode of operation, which can be either continuous, semicontinuous, or batch, must be determined. Factors to consider ate the operating conditions, the manufacturing demand, the composition of the product mix (single or multiple products), the amount of waste that can be tolerated, and the materials of constmction requirements. Criteria for the selection of hydrothermal reactor design maybe summarized as... 

Taking into account all the requirements and criteria for reactor type and collimator selection, we arrived at two potential a) a water-water "pool"-type reactor, and b) a reactor with liquid-metal Na-K coolant Both variants are simple to control, have increased reliability and safety, the heat is removed by natural convection without the use of pumps. Manufacturing costs are very low. 

Chapter 6 starts with criteria for the selection of a reactor configuration. Data are given for sizing reactors. Then the details are given for over 30 reactor configurations. 

The criteria for selection of laboratory reactors include equipment cost, ease of operation, ease of data analysis, accuracy, versatility, temperature uniformity, and controllabihty, suitability for mixed phases, and scale-up feasibility. 

The final probe of molecular clusters is that of selected chemical reactions. The use of probe reactions to study supported cluster catalysts is well established, and we are attempting the development of similar probes of unsupported clusters. The first steps in this direction are the design of a pulsed chemical reactor to go with the pulsed cluster source and the development of criteria for reactions. It is important to recall that at present... 

Selection Criteria for Chemical Reactions for Micro Reactors... 

Following a theoretical analysis of distributed small-plant manufacture, Benson and Ponton define assessment criteria for processes suitable for such processing [139]. Since micro reactors are one of the favorite and natural tools for distributed manufacture, this selection list also defines micro-reactor applications. In this context, the authors, probably in one of the first regular citations, emphasize that formulation processes, especially those with multiple ingredients, are particularly suited for distribution. The making of paint on-site is referred to as an already existing way to do so. It stands to reason to augment the scope from formulations to functional chemicals. 

All process development starts with chemistry. The selection criteria for the most suitable chemistry for a continuous process do not suffer from the same constraints as those for a large-scale batch process. For example, highly exothermic reactions are not only possible in a flow reactor, but are in fact preferred [47]. As operator exposure will be low and so will stock levels, different safety considerations come into play that may allow utilisation of otherwise intolerably toxic reagents. Process telescoping is a necessity to minimise the number of intermediate isolations. Examination of all these factors is facilitated by online analysis because of its speed and maintenance of experimental integrity (i.e. no requirement for sampling). 

The Stop Criteria page tab opens the window shown in Figure 4.28, on which one or more criteria for ending the batch cycle can be specified. We select a Time variable and set the Stop value to 7200 s (2 h). Other criteria could also be specified, such as a maximum reactor temperature and a desired concentration. 

Table 4. Criteria for selecting first wall materials8 in fusion reactors in general priority order28)...

Various types of reactors can be applied, and it is of primary importance to select the proper reactor to obtain the required information, which generally means that one should not mimic the reactor type in which the process will be carried out. Other criteria apply for practical reactor selection than for catalyst testing. Downscaling, as far as possible, is desirable because of lower equipment costs, lower material consumption, and disposal, lower utility requirements, reduced demands... 

First, consider a cmde design of the TBR. For a selective consecutive hydrogenation of the type assumed, it is desirable to use as small particles as possible, since this improves both the effectiveness factor and selectivity. The limitation is the acceptable pressure drop. If only these three performance criteria are considered, the optimal design is a reactor that is very short and with a very large diameter. There are obviously practical limits on the ratio between the length and the diameter of the reactor For highly packed... 

Selection of the laboratory reactor type and size, and associated feed and product handling, control, and analytical schemes depends on the type of reaction, reaction time scales, and type of analytical methods required. The criteria for selection include equipment cost, ease of operation, ease of data analysis, accuracy, versatility, temperature uniformity, and controllability, suitability for mixed phases, and scale-up... 

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