H2Tech - Q4 2022 - 29

POWER AND UTILITIES
also presents unique challenges that make
it an unlikely source of H2
for a pilot test.
Today, many industrial gas suppliers
are set up to provide H2
in relatively small
quantities for short-term applications or
on a long-term, recurring basis. For example,
a single trailer delivery of liquid H2
for a typical industrial customer might be
enough for a 6-mos supply. For these pilot
power projects, however, a test may require
as many as six gaseous or two liquid trailers
for a weeklong testing operation. A highlevel
comparison between gaseous and
liquid H2
deliveries is detailed in TABLE 1.
After determining the amount of H2
to be used.
chosen impacts the deis
much
. Highrequired
for a test, the next step is to identify
the source and type of H2
The type of H2
sign of the overall blending process. The
equipment setup for gaseous H2
simpler than that for liquid H2
pressure gaseous H2 can be connected
must be vaporized and its presdirectly
to the blending system, whereas
liquid H2
sure increased before it can be injected
into the fuel system. While liquid H2
can
be stored at significantly higher quantities
and lower pressures than its gaseous form,
it is extremely cryogenic, meaning it must
be kept at an extremely low boiling point
temperature near -423°F (-253°C).
From a pilot testing perspective, the
color of H2
used is less relevant since it
does not impact the equipment's operational
functionality during the short test
period. The designated H2
color (green,
blue or gray) is indicative of the carbon
emissions created during its production.
Today, most H2
vide gray H2
traditional methods (e.g., steam methane
reforming) for pilot tests.
Secure H2 early. Since pilot tests are
predicated on timely deliveries of H2
and
the large volume needed for the test duration,
orders must be placed early. Even a
single turbine or engine test can require
a significant amount of H2
over a brief
period. Determining the test volume required
will help expedite coordination
with industrial gas suppliers on H2
deliveries
that could be limited by quantity and
geographic location.
Logistics will evolve over time to address
supply chain challenges as utilities
consider H2
supply options that meet
externaltheir
long-term environmental and financial
goals. Instead of sourcing H2
FIG. 2. This schematic of a pilot testing blend shows the anticipated flow process.
H2Tech | Q4 2022 29
suppliers typically pro,
which is produced using
Location. The NFPA's rules for sitting H2
storage are detailed in NFPA 2-Hydrogen
Technologies Code, which provides
minimum setback requirements for both
liquid and gaseous H2
. Gaseous H2
system
setbacks are based on storage pressure and
piping size, while the setbacks for liquefied
H2
systems are based on storage volume.
During the conceptual design phase,
each pilot testing site should be evaluated
to determine the appropriate placement
of H2
trailers and other equipment to faly
in the future, utilities could produce it
onsite via the electrolysis of water. Water
electrolysis is a mature technology process
that utilizes an electrical current to divide
water molecules into oxygen and H2
.
When coupled with wind, solar or other
renewable energy sources to produce electricity,
water electrolysis generates zero
carbon dioxide (CO2
this method of H2
) emissions. Until
production becomes
more widespread, expect a significant increase
in liquid or compressed gas H2
liveries to accommodate pilot testing.
decilitate
testing while maintaining the required
spacing. NFPA 2 setbacks impact
the transportation of H2
trailers in and out
of the plant site, as well. Depending on the
space constraints at the facility, this may
also impact the choice of liquid or gaseous
H2
for the test.
The placement of tie-ins and equipment
for H2
blending matters. Tie-ins
to the plant's natural gas system must be
located in ways that minimize exposure
to existing components not originally designed
for H2
usage. Adequate pressure,
temperature and flow conditions per OEM
requirements, along with pertinent safety
devices, are also required in these locations.
These pilot projects typically require
two natural gas tie-ins: one to supply natural
gas to the blending system, and the
other at the point where the H2
and natural
gas mixture from the blending system
is injected into the existing fuel gas pipe.
The blending system typically consists of
a H2
transfer system, flowmeters and control
valves (FIG. 2).
TABLE 1. A high-level comparison between gaseous and liquid H2
denotes critical factors for each
Parameter
Approximate trailer capacity (each)
Maximum allowable working
pressure (MAWP)
Operating temperature
Trailer dimensions, l × w × h
Additional equipment required
Gaseous
660 lbs-880 lbs
2,400 psig-2,600 psig
Ambient
40 ft × 8 ft × 12 ft
Pressure regulation
Blending components
deliveries
Liquid
~7,500 lbs
150 psig
-423°F (-253°C)
40 ft × 8 ft × 12 ft
Pump (or compressor/vaporizer)
Blending components
Note: The properties in the table are typical conditions and may vary based on individual hydrogen suppliers.

H2Tech - Q4 2022

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