Application: Conversion of isobutylene contained in mixed-C4 feeds to isooctane (2,2,4 tri-methyl pentane) to produce a high-quality gasoline blendstock. The full-range of C4 feeds can be processed—from refinery FCC, olefin-plant raffinate and isobutane dehydrogenation processes. The NExOCTANE process is specifically developed to minimize conversion costs of existing MTBE units and offers a cost-effective alternative to MTBE production.
Products: Isooctene and isooctane can be produced, depending on the refiner’s gasoline pool. Flexibility to retain MTBE/ETBE production capability is also possible for a multipurpose swing plant. Typical product properties using C4 feed from FCC are:
Isooctene Isooctane
RONC 101.1 99.1
MONC 85.7 96.3
(R+M)/2 93.4 97.7
Specific gravity 0.73 0.70
Vapor pressure, psia 1.8 1.8
Distillation ASTM D86
T50, °F 221 216
T90, °F 238 234
EP, °F 380 390
Description: In the NExOCTANE process, reuse of existing equipment from the MTBE unit is maximized. The process consists of three sections. First, isobutylene is dimerized to isooctene in the reaction section. The dimerization reaction occurs in the liquid phase over a proprietary acidic ion-exchange resin catalyst, and it uses simple liquid-phase fixed-bed reactors. The isooctene product is recovered in a distillation system that generally can utilize the existing fractionation equipment. Recovered isooctene product can be further hydrogenated to produce isooctane. A highly efficient trickle-bed hydrogenation technology is offered with the NExOCTANE process. This compact and cost-effective technology does not require recirculation of hydrogen. In the refinery, the NExOCTANE
process fits as a replacement to MTBE production, thus associated refinery operations are mostly unaffected.
Process efficiency: The NExOCTANE process is optimized to minimize revamp costs but can also be designed for flexibility to multiple products (isooctene, isooctane, MTBE or ETBE) or to maximize product yield. In fact, >99% conversion of isobutylene with a selectivity of over 91% to isooctene can be achieved.
Licensor: KBR and Neste Jacobs OY.
