reactions for esterification 6.
esterification: alcohol + acid d [ester ]
ester + water dt product separation k + [alcohol ][ acid ]- k [ester][water ]
acceleration of the reaction reflux stages amount of catalyst residence time, temperature
Fig. 2.10 Interaction of reaction and separation
"separation performance" "reactor performance"
ture or by an increase in the amount of catalyst, the products have to be removed more rapidly in order to avoid a change in concentration.
We would like to refer to the intensity of product removal in a reaction column using the term separation performance and the property of converting the starting materials using the term reactor performance.
If a development engineer has to design an industrial column purely on the basis of miniplant experiments, he has to maintain not only the separation performance but also the ratio of separation performance/reactor performance so that main and secondary reactions proceed to a comparable extent in the industrial-scale reaction column. One way in which this can be achieved is in terms of construction by separating reaction and product separation from one another both in miniplant tests and on an industrial scale. This is possible, for example, when the reaction is carried out in the presence of a heterogeneous catalyst in the downcom-ing stream or with side reactors at the column. An alternative is to use structured packing with well-defined paths for the liquid flow. This problem has not yet been solved, the main reason being the lack of reference columns on an industrial scale. As we see it, the way forward is either:
- to develop scale-up methods or
- to carry out RD experiments on an industrial scale.
The latter possibility, which represents a step back to the process-engineering stone-age design of columns, will in many cases mean the end of the line for RD, since a company will rarely be prepared, for time and cost reasons, to build integrated experimental plants on an industrial or semi-industrial scale. So developing an appropriate scale-up procedure for reactive column internals is a key task. The second European project (INTINT) will hopefully provide some contributions.
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