Reactive distillation offers substantial process benefits lor both MTBE and ETBE production. The maximum isobutene conversion and ether purity for ETBE production are limited by the unfavourable reaction equilibrium, kinetics and azeotropes, when using the conventional technology. However, in a specially designed reactive column, these limitations can be overcome and conversions and purities above 99% can be achieved, matching the results attainable for MTBE production. The optimum design for ETBE columns is different to that which is commonly used for MTBE production. A shorter column and higher reflux ratio is required to optimise the reaction zone conditions and, therefore, maximise conversion. If extensive ETBE production is anticipated, a specific ETBE column design should be developed to maximise profitability. Alternatively, if only occasional ETBE production is required, standard MTBE equipment is sufficient as an isobutene conversion and ether purity of 90%+ can still be attained.
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