H2Tech - Q4 2021 - 16

SPECIAL FOCUS FUTURE OF HYDROGEN ENERGY
gas is evenly distributed to the available fiber surface to maximize
capacity and selectivity. Once the H2
concentration exceeds
30%, this enriched stream is sent to a PSA, where this gas is further
purified and the concentration is increased up to 99.9999%.
This technology is mature and market-ready. The first realscale
demo showcase is already under construction at Linde's Dormagen
plant near Düsseldorf in Germany, due to go onstream in
2021, and the first-reference customer is already up and running.
More than a pipe dream. The first projects to advance the
H2
FIG. 1. Bundle of polyimide hollow fibers that will be woven into a
membrane cartridge and packaged.
pipeline network are already underway. For example, in
Europe, 11 transmission system operators (TSOs) launched a
plan to collectively create the European Hydrogen Backbone
(EHB). The aim is to build and expand a functional H2
network
in Europe. The group, which has expanded to include 23
TSOs from 21 countries, published an updated report in 20212
outlining a more ambitious H2
According to the EHB, the H2
pipeline network plan.
infrastructure could grow to
become a pan-European network, with a length of 39,700 km
by 2040, encompassing 69% repurposed natural gas pipelines
and 31% newbuild H2
pipelines. Further network development
would be expected after 2040.
As movement is made toward these ambitious targets, a transitional
phase with interim solutions can be expected over the
next few decades. At this early stage in the H2
journey, it is highly
unlikely that any country or region will be able to produce
sufficient H2
from renewable sources to fill entire pipelines-
FIG. 2. Ready-to-run solution for efficient extraction of H2
natural gas pipeline blend.
from a
for optimal flow distribution. Furthermore, the hollow fiber design
allows for robust operation under high pressures and harsh
pressure fluctuations. This makes these modules more forgiving
of pressure shocks and reversal of transmembrane pressure than
conventional flat-sheet modules.
One key advantage of this membrane technology is its efficiency.
The pressure inherent in the natural gas blend is sufficient
to separate the H2
from the natural gas. No electricity or
additional resources, such as chemicals or water, are required.
How does PSA work? PSA technology takes advantage of the
fact that different gas molecules attach with different strengths
to the inner surface of porous solid materials, known as adsorbents.
In this case, methane attaches to the small adsorbent particles,
and the H2
this solid. The H2
remains more or less in the free volume around
is then extracted as a pure gas stream from the
top of the vessel.
At some point, the various adsorbents are saturated with methane
and other components of the natural gas, and the process is
halted. The vessel on the bottom is opened, relieving the pressure
and withdrawing the adsorbed species from the bottom of this
vessel. The system then switches to the next pressurized vessel
with the regenerated adsorbent, and the process begins again.
Membranes and PSA in a hybrid system. The hybrid solution
for H2
stages and one PSA step to maximize H2
16 Q4 2021 | H2-Tech.com
extraction is designed with one or more membrane
recovery rates. The feed
especially considering that typical international transmission
pipelines have a capacity in excess of 1 MM Nm3/hr. Blending
H2
a smooth transition toward a " greener " future. Over time, it is
expected that the share of H2
ate extraction and purification technologies adds to the flexibility
of H2
tional or low-carbon H2
.
at concentrations of 5% to 30%, and unused lines can be repurposed
to carry pure H2
Looking ahead. It can be said that H2
has the flexibility and
potential to speed the transition to a low- or zero-carbon economy
and, on the way there, to help decarbonize hard-to-abate
sectors like iron and steel, chemicals, oil refining and heavy
transport (e.g., trucks, ships, trains and aircraft).
Companies that cover every step in the value chain can
contribute to the accelerated adoption of H2
. This starts with
diverse production methods and extends through state-of-theart
gas conditioning and purification technologies. The value
chain also encompasses secure storage capabilities including
high-volume caverns and flexible delivery models such as cylinders
and bulk supplies. Now, leveraging innovative pointof-use
extraction and recovery technologies, innovative companies
are bringing greater flexibility and scale to the delivery
space by paving the way for " H2
on tap. "
NOTES
a
Commercialized by Linde and Evonik under the name HISELECT® powered
by Evonik.
LITERATURE CITED
Complete literature cited available online at www.H2-Tech.com.
As these figures illustrate, blending coupled with appropri.
It could be economically viable to blend conveninto
existing natural gas infrastructure
into natural gas will be the technology of choice in enabling
in these blends will increase.
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