Reactors for gas-solid

The most widely used reactors for gas-solid reactions in fine chemistry are fixed-bed tubular... 

Our treatment of Chemical Reaction Engineering begins in Chapters 1 and 2 and continues in Chapters 11-24. After an introduction (Chapter 11) surveying the field, the next five Chapters (12-16) are devoted to performance and design characteristics of four ideal reactor models (batch, CSTR, plug-flow, and laminar-flow), and to the characteristics of various types of ideal flow involved in continuous-flow reactors. Chapter 17 deals with comparisons and combinations of ideal reactors. Chapter 18 deals with ideal reactors for complex (multireaction) systems. Chapters 19 and 20 treat nonideal flow and reactor considerations taking this into account. Chapters 21-24 provide an introduction to reactors for multiphase systems, including fixed-bed catalytic reactors, fluidized-bed reactors, and reactors for gas-solid and gas-liquid reactions. 

Laboratory Reactors for Gas-Solid Catalytic Reactions Their Principal Features and Ratings... 

Of the different types of reactors that can be used, the stirred basket reactor is the most amenable to manipulation in terms of regimes (see Kenney and Sedriks, 1972). Such a reactor for gas-solid (catalytic) reactions was considered in Chapter 7 (Figure 7.4). Typically, to operate under chemical control conditions, say in a fully baffled 15-cm diameter reactor provided with an 8-cm turbine agitator, the speed of agitation should be in the range of 1000-5000 rpm (corresponding to an impeller tip speed of 24,000-120,000 cm/min). 

Figure 6.16 Modular microchannel reactor for gas-solid reactions. (Adapted from Ref.

This chapter focuses on description of microstructured reactors for gas-solid, gas-liquid, and three-phase processes, flow regimes, mass transfer considerations for various configurations of microchannels, design criteria, and evaluation of each reactor type. Special attention is devoted to Taylor flow in microchannels, as this flow regime is the most adapted for practical engineering applications. 

In heterogeneous non-catalytic reactors, the reaction medium is a two-phase medium. The two-phase reaction medium is composed of a gas phase and a solid phase for the reaction between a gaseous reactant and a solid reactant, whereas for the reaction between a gaseous reactant and a liquid reactant the reaction phase is a two-phase gas-liquid medium. The design of heterogeneous non-catalytic reactors for gas-solid reactions and gas-liquid reactions are discussed in this section. 

DESIGN OF MOVING BED REACTOR FOR GAS SOLID NONCATALYTIC REACTORS... 

Figure 10.6 Reactors for gas-solid noncatalytic reactions, (a) Packed bed and (b) moving bed.

Figure 4.10.6 Adiabatic fixed bed reactors for gas-solid catalytic reactions (a) simple fixed bed (b) rack type reactor with interstage injection of gas (c) rack type reactor with interstage cooling or heating (ErtI, Knoezinger, and Weitkamp, 1997).

Figure 4.10.8 Reactors for gas-solid reactions, for example, coal gasification (a) moving bed, (b) fluidized-bed, and (c) entrained-flow. Adapted from Moulijn, Makkee, and Van Diepen (2004).

Roumanie et al. [14] developed a silicon microstructured reactor for gas-solid heterogeneous catalysis, in particular for the dehydrogenation of methylcyclo-hexane. A cathodic Pt film sputtered on silicon pillars of 5 pm x 100 pm was applied. The activity of the sputtered Pt catalyst was an order of magnitude lower as compared to that of a similar catalyst prepared by impregnation of a Pt precursor onto an Y-alumina layer. The sputtering method is thus not advisable for the preparation of supported catalysts in microstructured reactors as lowered reactivity and leaching of the metals during reactions remain serious problems. 

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