Scale-down to Laboratory Reactors

CH3CH=CHCH0 + 2 H2 — CH3CH2CH2CH2OH which, for conditions selected here, is practically irreversible (Berty 1983.) 

Flow cross-section for 2-inch basket A=(2.54) (3.14)=20.27cm =2.03xl0 m  

The alternate possibility of building a laboratory tubular reactor that is shorter and smaller in diameter is also permissible, but only for slow and only mildly exothermic reactions where smaller catalyst particles also can be used. This would not give a scaleable result for the crotonaldehyde example at the high reaction and heat release rates, where flow and pore-ditfusion influence can also be expected. 

In the petrochemical industry close to 80% of reactions are oxidations and hydrogenations, and consequently very exothermic. In addition, profitability requires fast and selective reactions. Fortunately these can be studied nowadays in gradientless reactors. The slightly exothermic reactions and many endothermic processes of the petroleum industry still can use various tubular reactors, as will be shown later. 

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The scale-down to laboratory reactors involves a change of a number of reaction conditions [415] [393]. Industrial reactors operate at high superficial gas velocity and Re molds numbers (Re= 1000—10000), but laboratory reactors t5q)ically operate at much lower Reynolds numbers, implying that the resistance to convective heat and mass transfer around each particle is significantly larger. It is evident that neither heat fluxes nor mass flows can be reproduced in laboratory bench-scale units. 

Laboratory Bq)eriments, The scale-down to laboratory reactors involves a substantial change of the reaction conditions. Neither heat fluxes nor mass flows can be reproduced in bench-scale units (Rostrup-Nielsen et al., 1988a). 

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