increased use of diesel fuel, and improved automobile fuel efficiencies.
The strongest growth over the past decade has occurred in emerging regions such
as Asia, Russia, Middle East, and Latin America, which currently make up roughly
50 % of demand and is expected to rise to 58 % by 2025 (IHS CERA Annual LongTerm Strategic Workbook and Product Markets 2014). The drivers for growth
include large, growing populations and economies, increased wealth, and export
of goods and services.
Gasoline is subject to many local, national, and international regulations. New
regulations affecting gasoline composition have been enacted in most regions of the
world, driving the increase in demand for clean fuels. These regulations include
many clean fuel initiatives, including lead phase down; minimization of RVP,
sulfur, benzene, aromatics, and olefin content; and addition of oxygenates.
For example, Euro 5 motor fuel specifications, last updated in 2009, limit aromatics
to 35 vol.%, olefins to 18 vol.%, and benzene to 1 vol.% maximum. Currently many
non-EU countries are still in the planning phases of implementing either Euro 4 or
Euro 5 specifications. Table 5 shows the Euro 1–5 gasoline specifications
(Euro Fuel Specifications).
In the USA, the Environmental Protection Agency (EPA) sets the standards.
There are some variations from state to state, with California generally being the
most stringent. Gasoline specifications set by the California Air Resources Board
(CARB) have the following limits: 35 vol.% aromatic maximum, 1.1 vol.% benzene maximum, 10 vol.% olefins maximum, 10 vol.% ethanol minimum, RVP
6.4–7.2 psi, and sulfur less than 20 wppm. It should be noted that the US EPA’s Tier
3 sulfur limits have been set for 10 wppm maximum by 2017.
As indicated above, benzene content in gasoline is one component broadly
regulated. For instance, in the USA, the EPA has implemented a Mobile Source
Air Toxics (MSAT) rule to reduce hazardous air pollutants (US EPA MSAT
program regulations 2014). As of 2011, the EPA requires that refiners must meet
a maximum annual average gasoline benzene content of 0.62 vol.%. The maximum
permissible level is 1.3 vol.% as of July 2012. These are applied to US refiners as
well as gasoline imported into the USA.
Many of the items regulated for motor fuels are key components produced by
reforming naphtha. However, the catalytic reformer is typically part of a naphtha
complex, where the naphtha feed is divided into lighter and heavier fractions using
a naphtha splitter distillation column. The heavier fraction, typically C 7 + hydrocarbons, is sent to the reformer, whereas the lighter fraction, typically a C 5 /C 6
fraction, is sent to an isomerization unit, the subject of another chapter in this
handbook. The isomerization unit, such as the UOP Penex
TM process, for example,
saturates benzene to cyclohexane and converts the C 5 and C 6 paraffins and naphthenes to high-octane, highly branched paraffins.
One of the by-products from reforming, whether motor fuels or aromatics, is
hydrogen. Many reformers are critical for production of hydrogen in a refinery,
used for hydrotreating and hydrocracking processes. Some reformer units are
operated for hydrogen production at the expense of making reformate at a higher
octane than required.
Catalytic Reforming in Petroleum Processing
239
The strongest growth over the past decade has occurred in emerging regions such
as Asia, Russia, Middle East, and Latin America, which currently make up roughly
50 % of demand and is expected to rise to 58 % by 2025 (IHS CERA Annual LongTerm Strategic Workbook and Product Markets 2014). The drivers for growth
include large, growing populations and economies, increased wealth, and export
of goods and services.
Gasoline is subject to many local, national, and international regulations. New
regulations affecting gasoline composition have been enacted in most regions of the
world, driving the increase in demand for clean fuels. These regulations include
many clean fuel initiatives, including lead phase down; minimization of RVP,
sulfur, benzene, aromatics, and olefin content; and addition of oxygenates.
For example, Euro 5 motor fuel specifications, last updated in 2009, limit aromatics
to 35 vol.%, olefins to 18 vol.%, and benzene to 1 vol.% maximum. Currently many
non-EU countries are still in the planning phases of implementing either Euro 4 or
Euro 5 specifications. Table 5 shows the Euro 1–5 gasoline specifications
(Euro Fuel Specifications).
In the USA, the Environmental Protection Agency (EPA) sets the standards.
There are some variations from state to state, with California generally being the
most stringent. Gasoline specifications set by the California Air Resources Board
(CARB) have the following limits: 35 vol.% aromatic maximum, 1.1 vol.% benzene maximum, 10 vol.% olefins maximum, 10 vol.% ethanol minimum, RVP
6.4–7.2 psi, and sulfur less than 20 wppm. It should be noted that the US EPA’s Tier
3 sulfur limits have been set for 10 wppm maximum by 2017.
As indicated above, benzene content in gasoline is one component broadly
regulated. For instance, in the USA, the EPA has implemented a Mobile Source
Air Toxics (MSAT) rule to reduce hazardous air pollutants (US EPA MSAT
program regulations 2014). As of 2011, the EPA requires that refiners must meet
a maximum annual average gasoline benzene content of 0.62 vol.%. The maximum
permissible level is 1.3 vol.% as of July 2012. These are applied to US refiners as
well as gasoline imported into the USA.
Many of the items regulated for motor fuels are key components produced by
reforming naphtha. However, the catalytic reformer is typically part of a naphtha
complex, where the naphtha feed is divided into lighter and heavier fractions using
a naphtha splitter distillation column. The heavier fraction, typically C 7 + hydrocarbons, is sent to the reformer, whereas the lighter fraction, typically a C 5 /C 6
fraction, is sent to an isomerization unit, the subject of another chapter in this
handbook. The isomerization unit, such as the UOP Penex
TM process, for example,
saturates benzene to cyclohexane and converts the C 5 and C 6 paraffins and naphthenes to high-octane, highly branched paraffins.
One of the by-products from reforming, whether motor fuels or aromatics, is
hydrogen. Many reformers are critical for production of hydrogen in a refinery,
used for hydrotreating and hydrocracking processes. Some reformer units are
operated for hydrogen production at the expense of making reformate at a higher
octane than required.
Catalytic Reforming in Petroleum Processing
239