Improving the Accuracy of CEMS by Means of Multipath ...

IMPROVING THE ACCURACY OF CEMS BY MEANS OF MULTIPATH ULTRASONIC FLOWMETER

Toralf DietzR&D Divison Flow Solutions20. April 2015

2Toralf Dietz | NIST Workshop Smoke Stack Measurement20./21. April 2015

MEASUREMENT PRINCIPALULTRASONIC FLOW METER

cospAB vc

Lt

cospBA vc

Lt

BAABp tt

Lv 1-1cos2

vp - average velocity on measuring pathtAB.tBA- transit timesL - length of measuring pathD - diameter - installation angle to flow axisc - speed of soundk - calibration factor

pV vDkQ 2

4


MEASUREMENT PRINCIPALULTRASONIC FLOW METER

picture: nuclearpowertraining.tpub.com

·

2 ·

0.9

0.92

0.94

0.96

0.98

2 4 6 8 10

k-fa

ctor

lg Re


FLOW PROFILEUNCERTANTY CONSIDERATIONS


Swirl adds a velocity component!

FLOW PROFILEUNCERTAINTY CONSIDERATIONS

flow

Vnonaxial

Vaxial

Vsound

meter body bore

1.A

1.B

))tan(()cos( nonaxial

vvvLt

axialsoundAB

))tan(()cos( nonaxial

vvvLt

axialsoundBA

cospAB vc

Lt

cospBA vc

Lt


FLOW PROFILEUNCERTANTY CONSIDERATIONS

0.91

0.92

0.93

0.94

0.95

0.96

0.97

0.98

2 4 6 8 10

k-fa

ctor

lg Re

INVESTIGATION SINGLE PATH SYSTEMUNCERTAINTY CONSIDERATIONS

-8

-6

-4

-2

0

2

4

6

8

0 200 400 600 800 1000

mea

surin

g de

viat

ion

f →

flow rate Q →

10D straight input length+ single bend pipe 0°10D straight input length+ single bend pipe 45°10D straight input length+ single bend pipe 90°10D straight input length+ single bend pipe 135°10D straight input length+ single bend pipe 180°10D straight input length+ single bend pipe 225°10D straight input length+ single bend pipe 270°10D straight input length+ single bend pipe 315°

± 3%

20./21. April 2015 Toralf Dietz | NIST Workshop Smoke Stack Measurement 7

single bend10D upstream

INVESTIGATION SINGLE PATH SYSTEMUNCERTAINTY CONSIDERATIONS

-8

-6

-4

-2

0

2

4

6

8

0 200 400 600 800 1000

mea

surin

g de

viat

ion

f →

flow rate Q →

10D straight input length + single bend pipe 0°10D straight input length + single bend pipe 45°10D straight input length + single bend pipe 90°10D straight input length + single bend pipe 135°10D straight input length + single bend pipe 180°10D straight input length + single bend pipe 225°10D straight input length + single bend pipe 270°10D straight input length + single bend pipe 315°20D straight input length + single bend pipe 0°20D straight input length + single bend pipe 45°20D straight input length + single bend pipe 90°20D straight input length + single bend pipe 135°20D straight input length + single bend pipe 90° (2)20D straight input length + single bend pipe 180°20D straight input length + single bend pipe 225°20D straight input length + single bend pipe 270°20D straight input length + single bend pipe 315°

single bend20D upstream

± 1%

20./21. April 2015 Toralf Dietz | NIST Workshop Smoke Stack Measurement 8


Size: 2“ to 48“ Pressure: 100bar Dry, clean gas Machined meter body Accurately measured geometry Meters are calibrated at a flow

lab

FISCAL METERING GAS TRANSMISSIONULTRASONIC FLOW METER


FISCAL METERINGULTRASONIC FLOW METER

ACCURACY CLASSES

DOCUMENTS ISO 17089-1&2.A.G.A. Report 9OIML R137

Installation EffectsClass 1.0: less than 0.33%Class 0.5: less tan 0.16%

EXAMPLEPROJECT DIRECT CO2 MONITORING

11


SYSTEM OVERVIEWPROJECT DIRECT CO2 MONITORING

QAadjustment

QAadjustment

3D Laser –Adjustment

mastertools

A

CO2 Concentration Flow

MAC

CO2 mass

Stack


INSTALLATIONPROJECT DIRECT CO2 MONITORING


Installation FLOWSIC100:▸ Target uncertainty (as found): Uk=2 ≤ ±1.0%▸ 2-path system

― 60° path angle― Chordal layout, mid radius position

▸ Upstream of the flue gas scrubber▸ T = 165°C (330°F)▸ Inner diameter 6200mm (20.34ft)▸ approx. 5D downstream of a 90°-bend with guiding plates

Validation by▸ an extended measurement traverse at real conditions ▸ Comparison with thermo-dynamic model calculation

FLOW MEASUREMENTPROJECT DIRECT CO2 MONITORING


ADJUSTMENT TIME MEASUREMENTPROJECT DIRECT CO2 MONITORING

Zero flow check and SOS-checkEach device passed a zero-flow and a speed of sound check to reduce the manufacturing uncertainty

U (k=2)Time difference / µs 0.5Time absolute / µs 2.8


3D laser scanner on site for precise measurement of▸ Diameter. ▸ Path length and ▸ Path angle

0.1° error @ 60° path angle 0.3% velocity error

GEOMETRY PARAMETERPROJECT DIRECT CO2 MONITORING

Parameter (N2) value uRadius / mm 3102 7Path length 1 / mm 6135 5

Path length 2 / mm 6177 5

Path angle 1 / ° 57.66 0.1Path angle 2 / ° 57.63 0.1


UNCERTAINTY CONTRIBUTIONSPROJECT DIRECT CO2 MONITORING

0.00%

0.02%

0.04%

0.06%

0.08%

0.10%

0.12%

0.14%

0.16%

0.18%

2 5 10 15 20 25

rel.

stan

dard

unc

erta

inty

/ %

gas velocity / m/sradius path angle path length time abs time diff


Virtual adjustment: theoretically defined calibration function based on CFD calculations

„Virtual calibration“ of the flow meter · „Worst Case analysis“ – rotation of the flow profile ±0.6%

COMPUTATIONAL FLUID DYNAMICSPROJECT DIRECT CO2 MONITORING


UNCERTAINTY CONTRIBUTIONPROJECT DIRECT CO2 MONITORING

0.00%

0.05%

0.10%

0.15%

0.20%

0.25%

0.30%

0.35%

0.40%

2 5 10 15 20 25

rel.

Stan

dard

unc

erta

inty

/ %

gas velocity / m/s

flow profile process values disturbance probeintruding probe path position integration


-1.5%

-1.0%

-0.5%

0.0%

0.5%

1.0%

1.5%

0 5 10 15 20 25 30

Unc

erta

inty

(k=2

)

Gas Velocity / m/s

EXPECTED UNCERTAINTY FLOW MEASUREMENTPROJECT DIRECT CO2 MONITORING


: (1) continuous thermo-dynamic calculation- Process measurement- Model of the thermodynamic cycle

: (2) Mass balance analysis- Mass of burned coal- Chemical analysis the coal

: (3) extended traverse test measurement- Acceptance inspection

PROJECT DIRECT CO2 MONITORING

MessgerätVolumenstrom

MessgerätCO2-Konzentration

RG-Kanal

Emissions-Rechner

CO2-Frachtgemessen

Online-Kontrollrechn.

Online-Kreisprozess-berechnung

CO2-Frachtberechnet

Offline-Kontrollrechn.

Blockwirkungs-gradmessungmittelskalibrierterPräzisions-messtechnik(Basis Abnahme-regelwerk)

Werks-/ DKD-Kalibrierungen

MessgerätVolumenstrom

MessgerätCO2-Konzentration

RG-Kanal

Emissions-Rechner

CO2-Frachtgemessen

Online-Kontrollrechn.




CO2-Frachtberechnet

Offline-Kontrollrechn.

Blockwirkungs-gradmessungmittelskalibrierterPräzisions-messtechnik(Basis Abnahme-regelwerk)

Werks-/ DKD-Kalibrierungen

22Toralf Dietz | NIST Workshop Smoke Stack Measurement

Average deviation = 0.1% sigma: = ±1.4%

UNIT N1THERMODYNAMIC MODEL CALCULATION

20./21. April 2015


Average deviation: = -1.85% Sigma: = ±1.1%

UNIT N2THERMODYNAMIC MODEL CALCULATION

20./21. April 2015


Average deviation: = 0.81% Sigma: = ±1.0%

UNIT P1THERMODYNAMIC MODEL CALCULATION

20./21. April 2015


Average deviation: = 0.49% Sigma: = ±1.0%

UNIT P2THERMODYNAMIC MODEL CALCULATION

20./21. April 2015


method Period Unit N1 Unit N2 Unit P1 Unit P2

Total mass balance(U: 1.5%)

2 month 0.80%

Thermo dynamic model calculation(U: 1.5%)

1st month -0.10% 1.85% 0.81% 0.49%

2nd month 0.50% 2.50% 1.20% 0.50%

Extended Traverse(U: 1.3 .. 2.2%)

Single test -0.14% 1.86% 0.75% 0.47%

TOTAL CO2 MASS DIFFERENCESRESULTS


CEMS:▸ Measurement uncertainty of better than 1.5% is realistic for direct CO2 monitoring▸ Verification uncertainty is at the same level!

Recommendations for the Ultrasonic flow meter▸ Install with max. possible straight upstream length▸ Reduce the uncertainty by multi path layout (≥ 2path)▸ Use CFD analysis

― to find an optimized path layout (if you have the freedom)― And/or calculate a “dry” calibration function

▸ Do precise geometry measurement, especially― Path angle― Diameter

SUMMARY

MANY THANKS FOR YOUR ATTENTION.

Improving the Accuracy of CEMS by Means of Multipath ...

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