REACTOR DESIGN CONSIDERATIONS

Source Steve, E. H., Reactor Design Considerations, Chemical Engineering, pp. 96-98, December 1997. 

We can immediately see major reactor design considerations between batch, CSTR, and PFTR. Table 3-1 shows the first of many situations where we are interested in the design of a reactor. We may be interested in choosing rninimum volume or many other process variables in designing the best reactor for a given process. 

The small mismatch between required and achieved minimum operation temperature has the severe consequence that a special preabsorption stage has to be included in the reactor set-up in order to achieve the essential complete conversion. In this manner the partial pressure of the SO3 product is lowered before the last stage of conversion, rendering acceptable incomplete conversion of the overheated catalyst. If the reason why the catalyst docs not operate efficiently down to its solidification point could be eliminated one may circumvent the intermediate absorption stage and thus facilitate the reactor design considerably. 

The primary reactor design consideration was the arrangement of reactor components to insure rapid gas-solid contact. The measuring devices had to be capable of operating at high temperatures, and they had to have millisecond time constants. The internal reactor volume must be minimized. Catalyst volume was chosen to cause a detectable pressure change in the system during the experiment. 

Other reactor design considerations may be necessary in special cases. Monomer mass transfer, not normally a problem, can he important if the monomer- aqueous phase interface is small. This is more likely in systems involving gaseous monomers in which the large surface area of the monomer emulsion is not present. In such cases special attention must he paid to gas dispersion and transport. Giher factors that can have a significant effect on reactor design include latex viscosity, heat transfer rates, reaction pressure, and control mechanisms. 

One of the major uses of coal is to bum it directly in power plants our objective is to burn coal in an environmentally acceptable manner. This requires the removal of sulfur so that EPA standards for the omission of sulfur oxides in power plants are met. This paper briefly reviews the present state of the art for the chemical removal of sulfur from coal via an oxidation process. A brief summary of the existing sulfur removal processes and their economics along with the chemistry and kinetics of inorganic and organic sulfur removal from coal and the reactor design considerations are outlined. 

Reactor design considerations for coal liquefaction are discussed in another paper presented at this NATO School (106) and hence they will not be repeated here. 

The ability of isoprene to form heavies by attack on itself and other dienes has been demonstrated This observation then allows for reactor design considerations that will keep the isoprene partial pressure relatively low. 

CHAPTER 15 REACTOR DESIGN CONSIDERATIONS TABLE 15.4 Steam properties... 

Lab-on-a-chip devices of this kind, so-called micro-total analysis systems ((xTAS), are textbook examples of how an appropriate reactor design considerably facilitates analyses. These systems benefit from highly efficient heat transfer in different reaction zones, thus allowing for realizing a complete sequence of different reactions within a single reaction channel. It is for these reasons that jtTAS are particularly well suited for nucleic acid analyses by means of the polymerase chain reaction (PCR). Other fields of application comprise molecular diagnostics or forensics [53]. 

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