2020 REFINING PROCESSES HANDBOOK PROCESS CATEGORIES COMPANY INDEX ISOOCTANE Conversion of MTBE units via DIMER8® Application: The Dimer8 process uses a fixed-bed reactor followed by catalytic distillation to achieve final isobutene conversion at high dimer selectivity. The Dimer8 process is the most attractive technology for converting a refinery- and/or petrochemical-based methyl tertiary butyl ether (MTBE) unit for isooctene/isooctane production. Description: The selective dimerization of isobutenes over acidic ion-exchange resin produces isooctene or di-isobutylene (DIB). Oxygenates such as methanol, MTBE, water and tert-butyl-alcohol (TBA) are used as selectivators or modulators for the dimerization reaction to control the formation of heavier oligomers. The Dimer8 process uses a fixed-bed reactor followed by catalytic distillation to achieve final isobutene conversion at high dimer selectivity. The primary fixed-bed reactor can be a boiling point reactor or a watercooled tubular reactor (WCTR). The choice will depend on the finished product and operational requirements of the complex. Either reactor can be used to achieve high isobutylene conversion with excellent dimer selectivity. The unique catalytic distillation (CD) column combines reaction and distillation in a single unit operation. Continuous removal of heavier dimer product from the reaction zone enables further conversion of isobutene without loss of dimer selectivity. The use of CD eliminates the need for any downstream reaction/ fractionation system to achieve such performance. Isooctene can be used as a gasoline blendstock due to its excellent characteristics. Should olefin restrictions require a paraffinic product, the isooctene product can be saturated to isooctane in a trickle-bed hydrogenation reactor. Hydrogenation uses a base or noble metal catalyst, depending on the feed contamination level. Feed wash Makeup oxygenate Catalytic Primary reactor distillation column Oxygenate recycle Oxygenate recovery column C4 raffinate Water C4 feed Isooctene Offgas Wastewater H2 feed Olefin saturation unit Isooctane Licensors: Jointly licensed by Lummus Technology and Saipem. Contact: Technology@lummustech.com Process advantages include: * Easy implementation, minimum revamp changes, low capital cost, short schedule * > 90% isobutylene conversion * > 80% C8 selectivity * High flexibility * Simple control * High-octane/low-Rvp product for blending * Low utility consumption. Copyright © 2020 Gulf Energy Information. All rights reserved.http://www.hydrocarbonprocessing.com/