calibration of industry-standard lng flow meters under ... · calibration of industry-standard lng...

Calibration of Industry-Standard LNG Flow Meters Under Ambientand Cryogenic Test Conditions

Menne Schakel (VSL) & Asaad Kenbar (NEL)

LNGIII training, 29 May 2020

Two papers available

16-6-2020 LNGIII training 2

VSL website:

https://www.vsl.nl/sites/default/files/rtf/Liquid%20nitroge

n%20calibrations%20of%20industry-

standard%20LNG%20flow%20meters%20used%20in%

20LNG%20custody%20transfer_public.pdf

NEL website:

LNG metrology website:

https://lngmetrology.info/2020/01/Kenbar & Schakel, draft journal publication, 2020

Schakel, 2019, VSL website

https://lngmetrology.info/2020/01/

Assessment of LNG flow meter measurement uncertainty


▪ Investigate the onsite flow measurement uncertainty for small and mid-

scale LNG applications. Is LNG flow measurement uncertainty of 0.50%

(k = 2) met in practice?

▪ Effect of typical upstream flow disturbances on LNG flow measurement

uncertainty

▪ Effect of meter insulation on LNG flow measurement uncertainty

▪ Assess transferability of meter calibrations with water at ambient

conditions to cryogenic conditions

Test protocol - first step: water calibrations


Not displayed

Double bends

NEL’s Water Flow Measurement Facility

From Kenbar & Schakel, draft journal publication, 2020

Test protocol: typical flow disturbances


Moderate


Severe

Test protocol: typical flow disturbances



Test protocol


▪ I. Ideal setup: no flow disturbance, no insulation

▪ II. As setup I, but with partially blocking plate

▪ III. As setup I, but with double-bend disturbance


Test protocol


▪ 2” and 4”

▪ A total of 6 meters LNG flow calibrated and tested

▪ 3 flow geometries tested

▪ Ambient and cryogenic flow conditions

▪ With and without meter insulation

• Panametrics a

Baker Hughes

company

• Emerson

• Endress + Hauser

• KROHNE

• Yokogawa

Test protocol - second step: cryogenic calibrations


VSL Cryogenic Research and Calibration Facility

2” metering line with double bends (1) installed and

rockwool (2)

From Schakel, 2019, VSL website


Exactly the same metering lines

in cryogenic calibrations as

used in the water calibrations

Systematic assessment of LNG flow meter uncertainty


▪ I. Ideal setup: no flow disturbance and all meters are insulated

▪ II. As setup I, but with partially blocking plate

▪ III. As setup I, but with double-bend disturbance

▪ IV. As setup I, but with flow meter insulation removed


Water and cryogenic calibration results


-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0

Err

or

[%]

Mass Flow Rate [kg/s]

Water Flow TestsMeter 1

Ideal, 20 deg. C

Ideal, 36 deg. C

Partial blockage, 20 deg. C

Double-bend, 20 deg. C

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0

Err

or

[%]


Liquid Nitrogen Flow TestsMeter 1

Ideal

Ideal-repeat

Partial blockage

Double-bend

Un-insulated

Nominal

Rate

(kg/s) Ideal, 20 °C

1 -0.018

2 -0.010

3 0.048

4 0.044

5 0.017

6 0.004

7 -0.013

8.5 -0.018

Nominal

Rate

(kg/s) Ideal

2 -0.19

4 -0.10

6 -0.07

8 0.00

10 -0.04

From Kenbar & Schakel, draft journal publication, 2020 From Schakel (2019) & Kenbar and Schakel, draft journal publication (2020)



-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0

Err

or

[%]


Water Flow TestsMeter 6

Ideal, 20 deg. C

Ideal, 36 deg. C



Nominal

Rate


1 -0.026

2 -0.020

3 0.036

4 0.036

5 0.016

6 0.007

7 -0.006

8.5 -0.010

Nominal

Rate

(kg/s) Ideal

2 0.26

4 0.44

6 0.52

8 0.60

10 0.59


From Schakel (2019) & Kenbar and Schakel, draft journal publication (2020)



-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

0.0 5.0 10.0 15.0 20.0 25.0 30.0

Err

or

[%]


Water Flow Tests

Meter 0

Ideal, 20 deg. C

Ideal, 36 deg. C



-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 5 10 15 20

Err

or

[%]



Ideal

Ideal-repeat

Partial blockage

Double-bend

Un-insulated

Nominal

Rate


7 -0.041

16 -0.017

25 -0.018

35 -0.012

Nominal

Rate

(kg/s) Ideal

4 -0.07

8 0.02

12

16 0.13

20 0.10




-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

0.0 5.0 10.0 15.0 20.0 25.0 30.0

Err

or

[%]


Water Flow Tests

Meter 3

Ideal, 20 deg. C

Ideal, 36 deg. C



-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 5 10 15 20

Err

or

[%]



Ideal

Ideal-repeat

Partial blockage

Double-bend

Un-insulated

Nominal

Rate

(kg/s)

Ideal,

20 °C

7 -0.107

12 -0.115

17 -0.123

22 -0.145

28 -0.137

Nominal

Rate

(kg/s) Ideal

4 -0.21

8 -0.20

12 -0.12

16 -0.12

20




-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

0.0 5.0 10.0 15.0 20.0 25.0 30.0

Err

or

[%]


Water Flow Tests

Meter 4

Ideal, 20 deg. C

Ideal, 36 deg. C



-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 5 10 15 20

Err

or

[%]



Ideal

Ideal-repeat

Partial blockage

Double-bend

Un-insulated

Nominal

Rate

(kg/s)

Ideal,

20 °C

7 -0.155

12 -0.148

17 -0.118

22 -0.111

28 -0.135

Nominal

Rate

(kg/s) Ideal

4 0.67

8 0.43

12 0.38

16 0.27

20




-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

0.0 5.0 10.0 15.0 20.0 25.0 30.0

Err

or

[%]


Water Flow Tests

Meter 8

Ideal, 36 deg. C



-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 5 10 15 20

Err

or

[%]



Ideal

Partial blockage

Double-bend

Un-insulated

Nominal

Rate

(kg/s)

Ideal,

36 °C

7 0.204

16 0.021

25 -0.035

Nominal

Rate

(kg/s) Ideal

4 0.29

8 -0.25

12

16 -0.22

20 -0.22

From Kenbar & Schakel, draft journal publication, 2020From Schakel (2019) & Kenbar and Schakel, draft journal publication (2020)

Cryogenic flow stability


▪ Target per batch:

− 0.2 bar/minute

− 0.2 °C/minute

− Flow rate variability: 1% - 2%

▪ Achieved:

− Pressure_std < 0.03 bar for 120

s – 130 s batch

− Temperature_std < 0.10 °C for

120 s – 130 s batch

− Flow rate: ±1.5% for 2” line

− Flow rate: ±0.5% for 4” line

Conclusions





− Provisional LIN calibration uncertainty at 0.30% in mass flow rate:

Schakel, 2019

Conclusions





− For 85% of the LIN calibrations, total measurement uncertainty was < 0.50%:

“Taking into consideration the maximum combined measurement uncertainty of the cryogenic

facility of 0.30% (k = 2) the target measurement uncertainty of 0.50% (k= 2) can be achieved

provided that the standard error of the mean value, computed from the individual calibration

points per set flow rate, is smaller than 0.40%”


Conclusions


▪ Effect of typical upstream flow disturbances on LNG flow measurement

uncertainty

− Effect of 20D upstream flow disturbances investigated generally smaller than

±0.50% meter error

“…it can be said that meter errors within ±0.50% can be achieved for the cryogenic testing

with LIN at approximately -180 °C, even with the presence of the disturbances tested in this

work and no additional flow conditioning devices installed, in particular, for ultrasonic meters.

This also means that the influence of these flow disturbances on meter error is limited (i.e.,

contribution to meter error below ±0.50%), however it should be remembered that these

disturbances are followed by straight piping equivalent to 20 pipe diameters.”From Kenbar & Schakel, draft journal publication, 2020

Conclusions


▪ Effect of meter insulation on LNG flow measurement uncertainty

− Effect of insulation on measurement accuracy can be significant i.e. error >

±0.50%

− “The results show that the effect of removing the meter insulation on measurement accuracy

can be significant (i.e. error > |±0.50%|). The difference in the meter error between the

insulated and un-insulated cases varied between a minimum value of -0.01% and a maximum

value of 1.04%. Therefore, meter insulation is recommended when used in cryogenic service.”


Conclusions


▪ Assess transferability of meter calibrations with water at ambient

conditions to cryogenic conditions

− “The results indicate that the corrections used to transfer the water

calibration to LIN conditions resulted in meter errors, for the ideal case,

within ±0.50% for about 85% of the results.”From Kenbar & Schakel, draft journal publication, 2020

Conclusions – important note


“The results presented in this paper cannot be extrapolated, with meaningfully low uncertainty, to flow

meters of different type, size, model and make (manufacturer) than those tested..”


Conclusions – last remarks


▪ Other effects planned to investigate:

− Thermal insulation

− Multi-phase flow

− Meter inclination

− Coriolis meter response time

▪ More meters were included than originally planned

Acknowledgment

28/5/2020 LNGIII workshop 25

The participation and support received from the LNG flow meter

manufacturers is highly appreciated!

Thanks to:

▪Panametrics a Baker Hughes company,

▪Emerson,

▪Endress + Hauser,

▪KROHNE, and

▪Yokogawa

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