experienced steady growth over the past decade. Increasingly stringent regulations have been enacted in most regions of the world, driving the increased
demand for clean fuels. As a result, gasoline composition has been adjusted to a
greater extent using C 5 –C 7 isomerization processes. Light-naphtha isomerization technology plays a key role in meeting octane demand in the gasoline pool
for clean fuels and premium gasoline grades. Low octane naphtha feedstocks
are processed into isomerate with an octane number ranging from 80 to
93 RON. Isomerization involves the skeletal isomerization of a paraffin to a
more highly branched paraffin with the same carbon number. Several light
paraffin isomerization technologies are reviewed in this chapter, including
both process and catalyst technologies. Flow schemes and economics are
reviewed. Catalyst technologies include Pt containing zeolitic, mixed-metal
oxide, and chlorided alumina.
Keywords
Paraffins • Isomerization • Gasoline • Light naphtha • Butane • Pentane •
Hexane • Octane number • Chlorided alumina • Sulfated metal oxide • Zeolite
Introduction
Upgrading light hydrocarbon (C 4 –C 7 ) streams in refineries, petrochemical plants,
and gas processing plants has continued to increase in commercial application, as
the world demand for gasoline and petrochemicals has experienced steady growth
over the past decade. Increasingly stringent regulations have been enacted in most
regions of the world, driving the increased demand for clean fuels. As a result,
gasoline composition has been adjusted to a greater extent using C 5 –C 6 isomerization processes. These regulations include many clean fuel initiatives, including lead
phaseout, minimization of benzene, aromatics and olefin content, and addition of
oxygenates to gasoline.
Light-naphtha isomerization plays a key role in meeting octane demand in
the gasoline pool for clean fuels and premium gasoline grades. Low-octane
naphtha feedstocks are processed into isomerate with an octane number ranging
from 80 to 93 RON, depending on the process configuration, catalyst type, and
operating conditions. Isomerization involves the skeletal isomerization of a
paraffin to a more highly branched paraffin with the same carbon number.
As in alkylation, which is discussed elsewhere in this handbook, the more highly
branched paraffins have higher octane numbers. However, because of its nature,
isomerization may also affect some of the naphthene components and will also
saturate aromatics. Based on its chemistry, the isomerization process is one of the
most economic means available for reducing the benzene content in gasoline.
Several isomerization technologies are commercially available from various
licensors. These are fixed-bed process units that employ high-activity catalysts.
The reaction conditions promote isomerization and minimize hydrocracking.
The first commercial isomerization process dates back to the 1930s for
480
D. Sullivan et al.
demand for clean fuels. As a result, gasoline composition has been adjusted to a
greater extent using C 5 –C 7 isomerization processes. Light-naphtha isomerization technology plays a key role in meeting octane demand in the gasoline pool
for clean fuels and premium gasoline grades. Low octane naphtha feedstocks
are processed into isomerate with an octane number ranging from 80 to
93 RON. Isomerization involves the skeletal isomerization of a paraffin to a
more highly branched paraffin with the same carbon number. Several light
paraffin isomerization technologies are reviewed in this chapter, including
both process and catalyst technologies. Flow schemes and economics are
reviewed. Catalyst technologies include Pt containing zeolitic, mixed-metal
oxide, and chlorided alumina.
Keywords
Paraffins • Isomerization • Gasoline • Light naphtha • Butane • Pentane •
Hexane • Octane number • Chlorided alumina • Sulfated metal oxide • Zeolite
Introduction
Upgrading light hydrocarbon (C 4 –C 7 ) streams in refineries, petrochemical plants,
and gas processing plants has continued to increase in commercial application, as
the world demand for gasoline and petrochemicals has experienced steady growth
over the past decade. Increasingly stringent regulations have been enacted in most
regions of the world, driving the increased demand for clean fuels. As a result,
gasoline composition has been adjusted to a greater extent using C 5 –C 6 isomerization processes. These regulations include many clean fuel initiatives, including lead
phaseout, minimization of benzene, aromatics and olefin content, and addition of
oxygenates to gasoline.
Light-naphtha isomerization plays a key role in meeting octane demand in
the gasoline pool for clean fuels and premium gasoline grades. Low-octane
naphtha feedstocks are processed into isomerate with an octane number ranging
from 80 to 93 RON, depending on the process configuration, catalyst type, and
operating conditions. Isomerization involves the skeletal isomerization of a
paraffin to a more highly branched paraffin with the same carbon number.
As in alkylation, which is discussed elsewhere in this handbook, the more highly
branched paraffins have higher octane numbers. However, because of its nature,
isomerization may also affect some of the naphthene components and will also
saturate aromatics. Based on its chemistry, the isomerization process is one of the
most economic means available for reducing the benzene content in gasoline.
Several isomerization technologies are commercially available from various
licensors. These are fixed-bed process units that employ high-activity catalysts.
The reaction conditions promote isomerization and minimize hydrocracking.
The first commercial isomerization process dates back to the 1930s for
480
D. Sullivan et al.