long term stability of coriolis flowmeters in cryogenic fluids...•energy density is 2.4 time...
TRANSCRIPT
10/15/2018
Products Solutions Services
Long Term Stability of Coriolis Flowmeters in Cryogenic Fluids
LNG Workshop 2018
Iryna Marfenko – Product Manager Metrology
Endress + Hauser Flowtec AG
Slide 1 Product Management Metrology
10/15/2018
LNG Workshop 2018
Agenda
• Benefits of Coriolis meters in cryogenic fluids
• Temperature compensation
• Transferability of water-based calibration factors to cryogenics
• Example: Road tanker filling at Linde Gas
• Measurement analysis on long term stability
• New Coriolis technology for cryogenic fluids
• Conclusions
Slide 2 Product Management Metrology
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LNG Workshop 2018
Cryogenic Liquids
• Generally referenced as a gas that can be liquefied below -
150°C at atmospheric pressure
Cryogen Temperature
Methane -162° C
Oxygen -183° C
Nitrogen -196° C
Hydrogen -253° C
Helium -269° C
Argon -186° C
Slide 3 Product Management Metrology
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LNG Workshop 2018
Cryogenic Uses
• Cryogenics such as liquid Nitrogen are
used for extreme cooling in:
• Manufacturing Industry
• Medical & Pharmaceutical Industry
• Food & Beverage Industry
• LNG is liquefied at extreme low temps:
• Takes up 1/600th the volume of natural gas
• Energy density is 2.4 time higher than CNG
• Easy and economical way to transport natural
gas where no pipelines exist
Both fluids are monetarily
traded, hence the need to
measure loading and unloading
with a high degree of accuracy.
Slide 4 Product Management Metrology
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LNG Workshop 2018
Measuring Cryogenics with Coriolis
Coriolis technology presents many advantages for measuring cryogenics:
• Measure mass flow directly – avoids volume to mass conversions
• Compact design – short installation lengths; no straight runs required
• No moving parts or seals – low OPEX* and high repeatability
• High degree of accuracy – approved for custody transfer
Slide 5 Product Management Metrology
*OPEX: operating expenses
10/15/2018
LNG Workshop 2018
Temperature compensation
• Deflection of the measuring tubes is a direct function of
stiffness of the tubes
Slide 6 Product Management Metrology
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LNG Workshop 2018
Temperature compensation
• Deflection of the measuring tubes is a direct function of
stiffness of the tubes
• Tube stiffness is directly related to the mass flow
calibration factor
Slide 7 Product Management Metrology
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LNG Workshop 2018
Temperature compensation
• Deflection of the measuring tubes is a direct function of
stiffness of the tubes
• Tube stiffness is directly related to the mass flow
calibration factor
• Stiffness has a temperature dependency
Slide 8 Product Management Metrology
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LNG Workshop 2018
Temperature compensation
• Deflection of the measuring tubes is a direct function of
stiffness of the tubes
• Tube stiffness is directly related to the mass flow
calibration factor
• Stiffness has a temperature dependency
• Additional challenges for Cryogenic applications:
• Stainless steel tubes exhibit a nonlinear relationship between temperature
and tube stiffness at low temperatures
• Accuracy of published data for tube properties that allow for extrapolation
to lower temperatures
Slide 9 Product Management Metrology
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LNG Workshop 2018
Example: Thermal Expansion-Contraction/Change of geometry/Change of I
• Source: Johnson, Wesley (NASA Glenn Research
Center, Cleveland, OH United States); 25th Thermal
and Fluids Analysis Workshop (TFAWS); 4-8 Aug.
2014; Cleveland, OH; United States
Slide 10 Product Management Metrology
10/15/2018
• Stiffness of the tube is characterized by the spring constant (k)
� = � �, � � = � � Area moment of Inertia of tube (linear)
� = �(�) Young's Modulus (non linear below about -50°C)
• Therefore, for thermal compensation of the mass flow, I(T) and E(T) are considered.
• The non linear range below -50°C is accurately characterized at two points:
• -196°C (validated via NIST type tests)
• 20°C (meter calibration) with a non-linear interpolation in between.
LNG Workshop 2018
Temperature compensation
� = � �, �� = � �
Slide 11 Product Management Metrology
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LNG Workshop 2018
Coriolis Meters Calibrated in Water
Calibration
rig
Testing
equipment
National
standard
Global
reference
±0.000001% ±0.0001% ±0.0016% ±0.015%
• All meters calibrated with water
on ISO 17025 accredited and
traceable calibration rigs
• Establishes calibration factor for
meter at about 20°C in water
Slide 12 Product Management Metrology
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LNG Workshop 2018
Flow Calibration Results at NIST – Liquid N2
Uncertainty of NIST Test Rig
Re
lati
ve e
rro
r [%
]
Slide 13 Product Management Metrology
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LNG Workshop 2018
Today yes… But what about tomorrow?
• Market concern for continuous long
term exposure to extremely low
temperatures
• Particularly where temperatures are
continuously cycled such as in batch
loading of trucks
Slide 14 Product Management Metrology
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LNG Workshop 2018
Cryogenic Filling Process @ Linde Gas
Fluid Temperature
Nitrogen -196° C
Oxygen -183° C
Argon -186° C
• More than 150 Promass F (3”) in use for many years
• Meters are factory calibrated with water at about 20°C
• Fluids are liquefied oxygen, nitrogen and argon
• Typical ≈ five 20 ton batches per day @ 40 tons/h flowrate
• Data of 14 meters recorded and analyzed over 4 years
• ≈ 75,000 batches
Slide 15 Product Management Metrology
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LNG Workshop 2018
Cryogenic Filling Process @ Linde Gas - Overview
Event Condition Pump (P) Valve 1 (V1) Valve 2 (V2) Valve 3 (V3) Totalizer (m)
Start cooling Off Close Open Open Reset
Start filling � = ��� On Open Close Open Start
Stop filling � = ��� Off Close Close Close Stop
Filling stationWeighing scale Storage tank
���
���
��1
��
+
�3
�2��� = ���� - ��� ≈ 20 ton
���� ≈ 40 ton��� ≈ −150°&
� = ' � ()*+, ,+,
Slide 16 Product Management Metrology
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LNG Workshop 2018
Zero Point Adjustment
• No zero point adjustments were made after installation of
meters at Linde Gas
• Cryogenic fluids often start to boil as soon as the meter is “shut-
in” to perform a zero point
• It has been demonstrated that zero point adjustments can be
performed in an empty pipe condition with excellent results
• Short duration zero point verification on cryogenic fluids can
also be executed
Slide 17 Product Management Metrology
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LNG Workshop 2018
Cryogenic Filling Process @ Linde Gas
• On site factors that effect the comparison results of meter to weigh scale:
• Batch into “warm” meter → boiling during start phase
• Variable batch size → more or less overall uncertainty due to weigh scale resoluUon
• Downstream portion of piping remains filled but does not enter tanker
• Variability of station design
Slide 18 Product Management Metrology
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LNG Workshop 2018
Cryogenic Filling Process @ Linde Gas
Resolution weighing scale 20 kg ≈ 0.1%∆� = ��� − ���� = − ' ∆� ()R
ela
tive
err
or
of
∆�[%
]
Slide 19 Product Management Metrology
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LNG Workshop 2018
Data Format
• ∆� : Mean error of mass in [%] over the four year period
• .∆� : Standard deviation of mass in [%] over the four year period
• ∆�/0 : Drift of mass error per year in [%/a]
Slide 20 Product Management Metrology
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LNG Workshop 2018
Cryogenic Filling Process @ Linde Gas
Ar O2 N2
Me
an
err
or
∆�[%
]
Slide 21 Product Management Metrology
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LNG Workshop 2018
Cryogenic Filling Process @ Linde Gas
Ar O2 N2
Slide 22 Product Management Metrology
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LNG Workshop 2018
Cryogenic Filling Process @ Linde Gas
Ar O2 N2
Slide 23 Product Management Metrology
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LNG Workshop 2018
Cryogenic Filling Process @ Linde Gas
Ar O2 N2
In operation 6
Months
Slide 24 Product Management Metrology
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LNG Workshop 2018
New Coriolis technology for cryogenics
• Developed to address the need for accurate mass flow in liquids with entrained gas (i.e. boiling)
• Uses a secondary higher order resonance frequency to provide active compensation
Raw �1 und ρ1st mode
2nd mode
Corrected 21 and ρ
Active
Compensation!
Additional
information
Multi-frequency technology™
Slide 25 Product Management Metrology
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LNG Workshop 2018
What about LNG?
-200 -150 -100 -50 0 50
Temperature °C
�=�(�,�)O2
N2 Ar
LNG
H2O
• Water-based calibration factors have been demonstrated to be valid for a wide range of fluid densities
• Interpolation methods for determining tube mechanical properties have also been demonstrated to be valid
Density (kg/m3)
ArO2H2OCH4 N2
999 1141 139480747050
LNG
Interpolation
Slide 26 Product Management Metrology
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LNG Workshop 2018
Conclusions
Coriolis meters are suitable devices for mass flow measurement of cryogenic fluids
• Effects of temperature on mechanical properties of the meter tubes must be understood and adequately
compensated by the meter manufacturer
• The transferability of water-based calibration factors has been demonstrated to be valid for cryogenic
fluids, and specifically for custody transfer applications
Slide 27 Product Management Metrology
10/15/2018
LNG Workshop 2018
Conclusions
Coriolis meters are suitable devices for mass flow measurement of cryogenic fluids
• Effects of temperature on mechanical properties of the meter tubes must be understood and adequately
compensated by the meter manufacturer
• The transferability of water-based calibration factors has been demonstrated to be valid for cryogenic
fluids, and specifically for custody transfer applications
Coriolis devices exhibit excellent long-term stability in cryogenic fluids
• No evidence of systematic drift in one direction due to extreme temperature and temperature cycling
• Low levels of drift exhibited are likely attributed to small zero point shifts
Slide 28 Product Management Metrology
10/15/2018
LNG Workshop 2018
Conclusions
Coriolis meters are suitable devices for mass flow measurement of cryogenic fluids
• Effects of temperature on mechanical properties of the meter tubes must be understood and adequately
compensated by the meter manufacturer
• The transferability of water-based calibration factors has been demonstrated to be valid for cryogenic
fluids, and specifically for custody transfer applications
Coriolis devices exhibit excellent long-term stability in cryogenic fluids
• No evidence of systematic drift in one direction due to extreme temperature and temperature cycling
• Low levels of drift exhibited are likely attributed to small zero point shifts
New innovations such as Multi-Frequency Technology is available to further improve
Coriolis measurement results in cryogenic fluids
Slide 29 Product Management Metrology