Integrated etherification process with recycle post treatment

摘要

A multistep hydrocarbon conversion process for the production of ethers including methyl tertiary butyl ether (MTBE) from light paraffins and alcohols is disclosed. A mixture of C4 isoparaffins, normal paraffins, an etherification recycle and butane isomerization effluent enter a deisobutanizer column. Normal paraffins withdrawn from the fractionator are isomerized and returned to the fractionator, and isoparaffins are withdrawn from the fractionator and dehydrogenated. The resulting olefins enter an etherification zone for reaction of isobutene with a C2-C5 alcohol. Unreacted paraffins and olefins comprise a portion of the etherification effluent entering the deisobutanizer. After separation for recovery of the ether product, unreacted paraffins and olefins are passed through a dehydrogenation zone for saturation of the olefins and then returned to the deisobutanizer column. Normal butanes are withdrawn as a sidecut from the deisobutanizer. The sidecut passes to an isomerization zone and a mixture of isobutane and normal butane is recycled to the deisobutanizer. In a highly preferred embodiment, spent catalyst from the isomerization zone fulfills the catalyst requirement of the dehydrogenation zone.