H2Tech - Q3 2021 - 48

MEASUREMENT AND INSTRUMENTATION
ment points, it will have a significant detrimental effect on measurement
accuracy, where flowmeters are designed to operate in
one specific phase.
Impurities in CO2
surement is coping with impurities in the CO2
streams. Another major challenge for meastream,
which
vary depending on the capture process, capture technology and
fuel source used. Without knowing the exact phase envelope
and physical properties of the CO2
across the CCUS chain:
1. Composition measurement of the CO2
2. Determination of physical properties
3. Flow measurement.
Sampling of the CO2
stream, it can be extremely
difficult to control the CCUS processes and undertake accurate
flow measurement (FIG. 2).
Three main measurements are essential to monitor CO2
mixture
stream is necessary to determine the
CO2 concentration and for the regulatory reporting of other
non-CO2 components in the stream. As the composition of the
stream will vary continuously, sampling points are necessary at
the capture plant and at various points throughout the transportation
network where the composition can vary.
P
Capture
plant
F
S
P
P
Capture
plant
S
P
F
Sampling
Physical properties
(phase, density,
compressibility)
Flow measurement
F
S
P
Final
reservoir
Industry standards
Phase envelope/
physical properties
generator tool
CO2
models/
equations of state
FIG. 3. An integrated measurement system in a shared pipeline.
48 Q3 2021 | H2-Tech.com
S
F
S
P
Shared
pipeline
S
F
S
P
F
Ensuring flow measurement certainty. After the composition
of the stream has been measured, the physical properties
can be calculated to provide the necessary data for handling
and transporting the CO2
throughout the different parts of
the CCUS network and for flow measurement purposes. New
equations of state and phase diagrams must be established to
accommodate the many different CO2
to arise in CCUS schemes.
Physical properties software modeling packages can be used
to generate new data for the different CO2
mixtures. However,
mixwide
variation in results can exist between different software
packages and algorithms when used to model the same CO2
ture. It may be necessary, therefore, to establish validated industry
standards and tools to minimize inconsistencies and ensure a
uniform approach. This is particularly important in cases where
different parties are sharing the same CCUS network (FIG. 3).
Flow measurement, in conjunction with the CO2
tion derived from the sampling of the CO2
calculate the transfer of CO2
concentrastream,
is required to
on a mass basis across the CCUS
measured, it is essential to
chain. To meet the EU ETS required measurement uncertainty
of ±2.5% for the total mass of CO2
Capture
plant
F
Capture
plant
install the correct type of flowmeter at locations along the network
where the flow conditions are stable, and in the specific
phase under which the flowmeter is designed to operate. This
may necessitate the use of gas meters at certain locations and
liquid meters at other locations along the network.
To ensure and maintain a traceable measurement uncertainty
for the purpose of regulatory reporting, flow measurement systems
should be calibrated, maintained and inspected at regular
intervals. Flowmeters should be calibrated at traceable laboratories,
using CO2
at the conditions and ranges under which they
will be required to operate. Any secondary instruments used to
convert into mass flow, such as pressure, temperature and density
instruments, should be calibrated and traceable to national
standards and located as close as possible to the flowmeter.
The ability to accurately measure the amount of CO2
sequesS
P
F
Capture
plant
tered
will be a fundamental foundation of large-scale CCUS, but
this presents some interesting technical challenges that require
an integrated approach to resolve, such as real-time determination
of process stream composition, bulk flowrate and fluid properties.
The essential technologies exist, but the challenges of integration
and economic viability should not be underestimated.
TÜV SÜD National Engineering Laboratory operates a tracecalibration
facility for domestic gas flowmeters, and a prirefueling
station dispensers
able H2
mary flow standard for validating H2
is in development. In addition, capabilities developed for CCUS
include gas flowmeter calibration with CO2
and CO2/N2
mixtures
at up to 1,000 m3/hr at 25 bar, as well as a facility for testing
densitometers, sampling systems and various sensors with CO2
and CCUS mixtures in liquid, gaseous or supercritical states. As
the energy transition progresses, it is essential that the UK's National
Measurement System has the capability to support industry
needs to meet the target of net zero emissions by 2050.
DALE ANDERSON is a Clean Fuels Engineer at TÜV SÜD
National Engineering Laboratory (NEL), where his primary focus
is understanding the flow measurement challenges for H2
, CO2
and LNG. Since joining NEL, he has been involved in various
projects related to the design and uncertainty assessment of
physical testing facilities. Part of the TÜV SÜD Group, NEL is the
UK's Designated Institute for Flow and Density Measurement.
mixtures that are likely
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