Alkylation of benzene and 1 -dodecene



There arc various choices of liquid flow pass when installing them above the sieve for different requirement as shown in Fig. 4. But it is found that when operating at the high conversion, the conversion level will increase in case of decreasing the number of liquid flow passes because the liquid load per weir length increases. It is believed that the liquid hold-up is usually much higher in sieve tray columns as compared to packed columns. And this is an favorable when carrying out relatively slow, catalysed, liquid phase reactions. So in this case catalytic distillation with tray columns is advisable.

Fig. 5 shows the structure of a wire-gauze catalyst envelop above the sieve tray [30J. This structure may be as in the Katapak-s and katamax constructions of Sulzer Chemtech and Koch-Glitsch. An advantage of a catalytic sieve tray construction is that contacting on any tray is cross-current and for large diameter columns there will be a high degree of staging in the liquid phase. This is favorable from the viewpoint of selectivity and conversion.

(b) Catalyst envelopes disposed on tray

(b) Catalyst envelopes disposed on tray

Fig. 3. Catalyst bales above the sieve tray; adapted from the source [29].


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