OilHyd (Oilgomerization-Hydrogenation) process utilizes butylenes from FCC units or other petrochemical processes to solve the problem of octane shortage in gasolinen production so as to comply with new specifications of gasoline. Industrial isooctane with high octane number is obtained via two-stage oilgomerization and hydrogenation. The co-product butane is the main component of automotive LPG. This process will be helpful to the campaign of "Replacing Gasoline by Natural Gas" in many cities in China. As a "clean" process, it employs T-99 solid phosphoric acid catalyst and XT 422-2 hydrogenation catalyst. In oilgomerization, supercritical and subcritical phase technologies are adopted so that catalyst lifetime and selectivity to dimerization products are greatly improved. The main products of OilHyd process contain about 90% alkanes, 20mg kg-1 sulfur and 10% olefins. Motor gantry tests show that the product's RON is more than 100.
As the stricter requirement of new automobile fuel specifications, the content of olefins and aromatics in gasoline has been limited in the world. Besides, the addition of MTBE in gasoline pool will be gradually forbidden. There is a shortage of octane number in the gasoline production.
The change of gasoline specifications has increased the significance for alkylate to be used as the gasoline blending component. The main composition of alkylate is high-branched isooctane, which is a perfect gasoline blending component. The alkylate possesses such characteristics as low RVP, high octane and mild boiling range. In order to adapt to the new situation, many refineries are struggling to increase the production of alkylate.
UOP made use of the combination of its original processes and developed an indirect alkylation process, InAlk, a process of butylene oligomerization and hydrogenation to produce high octane alkylate, and the process can be used to revamp existing MTBE processes. Its feedstock can be the material streams from FCC and ethylene unit, the butylene from the butane dehydrogenation unit, or butylenes and C3~C5 olefins. Two kinds of catalysts can be used in the InAlk process. The cation exchange resin catalyst is mainly used for the conversion of isobutylene, and solid phosphoric acid catalyst can be used to convert the n-butylene as well. The catalysts for hydrogenation can be selectable from these two kinds of catalysts, noble or non-noble catalysts. The unit in Japan is the third alkylate manufacturing unit by UOP beginning to build in 1999. Snamprogentti's ISOETHER100 process, oligomerization and hydrogenation for the production of octane blending component, makes use of the raffinate butylenes as its raw material, and it is called as non-liquid acid alkylation technology.
The replacement of ordinary gasoline by CNG/LPG/LNG is an increasing tendency in many places in China, and it is one of objects of "The clean automobile action". Different from the situation using gasoline as fuel, the contents of CO, HC, and NOx in the exhaust from the automobile decrease dramatically. Now, nineteen cities in China have taken a part in this action.