Hydrocarbon Processing - May 2022 - 49

Carbon Capture/
CO2
Mitigation
K. BRUN, Elliott Group,
Jeannette, Pennsylvania
CO2
compressor technology
for a decarbonized energy economy
Due to the potential of hydrogen (H2
)
in the context of developing a decarbonized
energy infrastructure, technologies
for efficiently producing, transporting,
storing and utilizing it have attracted significant
investment.
Of the three H2
2. The transport of H2
to its
end-use site, either an industrial
facility or a power plant
3. The transport of CO2
to
production processes
commonly used on an industrial scale
(steam reforming, partial oxidation gasification
and electrolysis), two require hydrocarbons
for feedstock and emit significant
amounts of carbon dioxide (CO2
)
as a byproduct-the outlier is electrolysis,
which requires only water and an electric
power source and can be powered by
renewable energy. Steam reforming and
partial oxidation gasification, by contrast,
are complex chemical processes that
convert a fossil fuel (natural gas or coal,
respectively) into H2
, carbon monoxide
(CO) and other compounds.
Due to the low cost of fossil fuels and
corresponding plant process equipment,
98% or more of H2
relatively inexpensive process, particularly
in North America where natural gas
is abundant; even were gas prices to rise,
the conversion of coal to H2
now produced is deis
a proven,
would still be
both commercially viable and less expensive
than electrolysis. Therefore, the most
realistic path to decarbonization involves
the sequestration of CO2
the H2
production process, rather than its
elimination. As such, three important gas
streams must be managed, even in a decarbonized
economy:
1. The production of natural gas,
followed by its transportation
to a site where it can be
converted into H2
Pump
CO2 out 2,100 psia
Electric motor
Cooler
FIG. 2. Intercooled centrifugal barrel compressor feeding a dense phase pump.
Hydrocarbon Processing | MAY 2022 49
CO2 in 30 psia
(Q = 32 kg/sec)
emitted during
Compressor
rived using one of these two methods.
Converting natural gas to H2
Cooler
Cooler
an appropriate geological
sequestration and end-storage site.
These gas streams will require substantial
compression. As the complexities
of both natural gas and H2
compression
have been extensively covered
elsewhere, this article is chiefly concerned
with solutions for the compression
and transport of CO2
. While CO2
compression has been successfully undertaken
for many years as part of acid/
sour gas injection and enhanced oil recovery
projects, the scale-up required
for carbon separation and sequestration
in a decarbonized H2
scenario would
challenge even technologies now considered
state-of-the-art. Because of this,
a need exists for new CO2
compression
applications for separation, transport
and storage injection.
FIG. 1. Compression start and endpoint
on CO2
pressure-enthalpy diagram.
CO2
pressure of CO2
newly produced H2
compression: An overview. The
gas separated from the
is strongly dependent
on the type of separation process
utilized: as such, it can vary from only
slightly above atmospheric pressure to
several hundred psi. Additionally,
significant
uncertainty surrounds geological
formation injection pressure, since it
depends strongly on the type of formation
and its drilled depth of injection.
Gear
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