Industrial Aplication of Catalytic Systems for n-Heptane Isomerization

Abstract

The ideal gasoline must have a high pump octane number, in the 86 to 94 range, and a low environmental impact. Alkanes, as a family, have much lower photochemical reactivities than aromatics or olefins, but only the highly branched alkanes have adequate octane numbers. The purpose of this work is to examine the possibilities of extending the technological alternative of paraffin isomerization to heavier feedstocks (i.e., n-heptane) using non-conventional catalytic systems which have been previously proposed in the literature: a Pt/sulfated zirconia catalyst and a molybdenum sub-oxide catalyst. Under the experimental conditions at which these catalysts have been evaluated, the molybdenum sub-oxide catalyst maintains a good activity and selectivity to isomerization after 24 h, while the Pt/sulfated zirconia catalyst shows a higher dimethylpentanes/methylhexanes ratio, probably due to a lower operating temperature, but also a high formation of cracking products, and presents signs of deactivation after 8 h. Though much remains to be done, the performance of these catalysts indicates that there are good perspectives for their industrial application in the isomerization of n-heptane and heavier alkanes.

Effect of phosphomolybdic acid on the catalytic behavior of bifunctional Pt‐Cr/nanocrystalline Y zeolite in hydroisomerization of n‐octane

“…One of the main sources of pollution in large cities is the aromatic hydrocarbons produced by gasoline vehicles . Therefore, fuel quality modification and the use of high‐octane gasoline are serious environmental challenges .…”

“…The conventional reaction for octane number enhancement is the hydroisomerization of n ‐alkane in the oil refining industry . In this reaction, straight chains of paraffin are converted to branched chains with higher octane numbers . Consequently, sources of pollution containing lead or aromatic components in gasoline can be reduced …”

“…One of the main sources of pollution in large cities is the aromatic hydrocarbons produced by gasoline vehicles. [1,2] Therefore, fuel quality modification and the use of high-octane gasoline are serious environmental challenges. [3][4][5] The conventional reaction for octane number enhancement is the hydroisomerization of n-alkane in the oil refining industry.…”

“…[6,7] In this reaction, straight chains of paraffin are converted to branched chains with higher octane numbers. [1] Consequently, sources of pollution containing lead or aromatic components in gasoline can be reduced. [7,8] In the process, the n-alkanes are isomerized in the presence of hydrogen over a bifunctional catalyst, including both an acidity, for example, Al 2 O 3 , zeolites, and a hydrogenation/dehydrogenation function, for example, Pt or Pd.…”

Model and simulation of a pentane isomerization reactor for naphtha stream in oil refining

“…Both compounds are isomers. This technique is widely used by the petroleum industry, due to it is a reaction used to transform nparaffin of low octane number into i-paraffins of high octane [5]- [7]. This process increases the fuel purity and the plant profitability [8].…”