U.S. exports of
butane continued to rise through 2024, hitting record levels, according to the
EIA. Butane is a natural gas liquid, or liquid petroleum gas, that occurs in
two forms, called isomers. These are normal butane and isobutane, both (C4H10),
but in different atomic arrangements. According to Wikipedia:
“Butane exists as two isomers, n-butane with connectivity
CH3CH2CH2CH3 and iso-butane with the formula (CH3)3CH. Both isomers are highly
flammable, colorless, easily liquefied gases that quickly vaporize at room
temperature and pressure.”
Butanes can be processed out of natural gas, which accounts
for most of their production, or refined from petroleum. Butane is often a lesser
component of LP gas, the main component of which is propane (C3H8). The two butanes
have a much lower vapor pressure than propane, which makes them more desirable for
certain applications. They are used as refrigerants and as propellants. Eric
Hahn of Elgas explains:
“Vapour pressure is the pressure exerted by the vapour
(gas), in equilibrium with the liquid, against the walls of the cylinder or
other closed container at a given temperature.”
“Propane has approximately 4x the vapour pressure of
butane and about 2.75x the vapour pressure of isobutane. (See properties chart below).”
“Propane, butane and isobutane gases may be used
individually or in combinations to achieve the desired pressure.”
“The lower pressures of butane and isobutane tend to be
favoured for everything from deodorant to disposable cigarette lighters.”
“When the product label lists “hydrocarbon” as the
propellant, it is often butane or isobutane.”
“Propane, butane and isobutane gases replaced
chlorofluorocarbons (CFCs) as propellants about 30 years ago.”
Both isobutane (R-600A)
and normal butane (R-600) are used as refrigerants, in different applications. Propane
refrigerant R-290A is a mixture of isobutane and propane. The butanes are also
favored over propane for use in heating greenhouses. This is due to the extra carbon
atom in the butanes (C4 vs. C3 of propane) which means about one third more CO2
is released into the plant-growing atmosphere which increases growth rates.
Butane is used as
a cooking fuel and isobutane, often made from butane, is used as a winter gasoline
additive to increase octane levels. Butane is also used as a base chemical for
making plastics and rubber.
U.S. Butanes Production and Exports
The EIA notes that
increased production and exports of butanes derive from some of the shale
plays, including the Eagle Ford in South Texas, the Marcellus of Pennsylvania and
West Virginia, and the Utica of Ohio. As the first graph shows, exports began in
earnest around 2014 and have continued to grow steadily since then reaching
record levels in 2024. As the second graph shows, Asia and Africa are the
biggest buyers of U.S. butanes. Butane is less expensive to store and transport
in warmer climates than propane due to its higher boiling point. The U.S. is
the largest butane exporter in the world.
EIA notes the following
about butane exports by country:
“The top Asian importers were Indonesia, Japan, and South
Korea, while Morocco and Egypt took in the most U.S. butane in Africa. These
five countries account for more than half of the United States’ butane exports.”
Butane is not the best fuel for cold environments because it vaporizes, or boils off, changing from a liquid to a gas at temperatures just below freezing. Governments in developing countries in warm environments have subsidized butane as a replacement for other fuels, such as wood or charcoal, because it is a cleaner indoor burning fuel for uses such as cooking or heating. This gives it the ability to aid human health, particularly the health of women and children, where charcoal, wood, and dung have been used for indoor cooking. As the following graph shows butane prices have risen since 2020 and the price spreads for the different regions also vary by year. One thing that can be seen in the graph is the effects on pricing due to the increased butane output and exports from U.S. shale fields beginning around 2015. The 2022 bump is mainly a result of the reshuffling of supply and demand due to sanctioning Russian supply.
I made a couple of graphs from EIA data below of isobutane field production in the U.S. and isobutane exports. While field production has nearly tripled since 2010, exports have dropped a little. I believe the result of this means that more isobutane is derived as a byproduct of natural gas processing rather than being made through the isomerization of normal butane.
In 2012, according to Callie Mitchell
of RBN Energy, 53% of isobutane came from gas plant isobutane supply and 47% from
merchant isomerization supply. They note in an article from 2013:
“The isobutane market has a traditional self-correcting
mechanism whenever the market gets oversupplied - the iso vs. normal spread
declines, the merchant isomerization units shut down, and the market moves back
into balance. But there is a potential
problem ahead for this orderly, self-correcting marketplace – shale. As high-BTU, “wet” shale gas production
continues to push NGL volumes from gas plants ever higher, the supply of
isobutane will be increasing proportionally.
The math is simple. The more gas
plant production of isobutane, the less merchant isomerization will be needed.”
An article in
Faster Capital notes that natural gas processing to extract isobutanes has been
improving in recent years with new techniques being deployed, including mobile
units that can process it in shale gas fields. Part of that section of the article
is reproduced below.
Isobutane, a key component of natural gas liquids (NGLs),
has emerged as a valuable resource in the energy industry. With its numerous
applications, from being a feedstock for petrochemical production to serving as
a clean-burning fuel, the demand for isobutane has been steadily increasing. As
a result, there has been a surge in innovations and technological advancements
in the extraction and processing of isobutane, aiming to optimize its
production and enhance its overall efficiency.
1. Enhanced Extraction Techniques:
Traditionally, isobutane is extracted from natural gas
through a cryogenic distillation process. However, recent innovations have
introduced more efficient extraction techniques. One such advancement is the
use of adsorption processes, where specialized adsorbents are employed to
selectively separate isobutane from other components of natural gas. This
method not only reduces energy consumption but also improves the purity of the
extracted isobutane.
2. Membrane Separation Technology:
Another notable innovation in isobutane extraction is the
utilization of membrane separation technology. Membranes with selective
permeability properties are employed to separate isobutane from natural gas
mixtures. This method offers several advantages, including lower energy
requirements, compact equipment design, and the ability to handle a wide range
of feed gas compositions. Membrane separation technology has proven to be a
cost-effective and environmentally friendly alternative to traditional extraction
methods.
3. Advanced Catalytic Processes:
Technological advancements have also revolutionized the
processing of isobutane. Catalytic processes, such as alkylation and
dehydrogenation, have been developed to convert isobutane into more valuable
products. Alkylation involves combining isobutane with olefins, such as
propylene or butylene, to produce high-octane gasoline blending components. On
the other hand, dehydrogenation converts isobutane into isobutene, which is a
key building block for the production of synthetic rubber and plastics. These
catalytic processes not only maximize the utilization of isobutane but also
contribute to the development of a sustainable and circular economy.
4. Modular and Mobile Processing Units:
In recent years, there has been a growing trend towards
modular and mobile processing units for isobutane extraction and processing.
These compact and portable units offer flexibility in terms of location and
capacity, enabling rapid deployment and cost-effective operations. They are
particularly advantageous in remote areas or for temporary production needs.
For example, modular skid-mounted plants can be easily transported to shale gas
fields, enabling on-site extraction and processing of isobutane, thereby
reducing transportation costs and improving overall efficiency.
5. Automation and Digitalization:
The integration of automation and digitalization
technologies has significantly enhanced the efficiency and reliability of
isobutane extraction and processing. real-time monitoring systems, advanced
control algorithms, and data analytics enable operators to optimize process
parameters, minimize energy consumption, and improve product quality. Moreover,
digital twin technology, which creates a virtual replica of the physical plant,
allows for simulation and optimization of various scenarios, further improving
operational efficiency and reducing downtime.
References:
U.S.
butane exports reached a new record in 2024. Energy Information Administration.
March 6, 2025. U.S.
butane exports reached a new record in 2024 - U.S. Energy Information
Administration (EIA)
Petroleum
& Other Liquids. Energy Information Administration. U.S.
Field Production of Isobutane (Thousand Barrels)
Butane.
Wikipedia. Butane - Wikipedia
Butane
vs Propane vs LPG Gas – Isobutane vs Butane – Properties. Eric Hahn. Elgas. Butane
vs Propane vs LPG Gas - Isobutane vs Butane - Properties
You
Can Just Iso my Butane: Isobutane and Isomerization in the Shale Gas World-Part
II. Callie Mitchell. RBN Energy. March 13, 2013. You
Can Just Iso my Butane: Isobutane and Isomerization in the Shale Gas World-Part
II | RBN Energy
Isobutane:
Unlocking the Potential of Isobutane in Natural Gas Liquids. Faster Capital. Updated:
26 Jun 2024. Isobutane:
Unlocking the Potential of Isobutane in Natural Gas Liquids - FasterCapital
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