Performance of an 8-path gas ultrasonic meter with and without flow conditioning. Dr Gregor Brown Caldon Ultrasonics Cameron

Transcription

1 Performance of an 8-path gas ultrasonic meter with and without flow conditioning Dr Gregor Brown Caldon Ultrasonics Cameron

2 Introduction Brief history of the Caldon ultrasonic meters Why 8-paths? Additional features of the Caldon LEFM 380Ci 8- path gas USM Testing performance to the requirements of the ISO, OIML and AGA standards 4-path and 8-path results presented and compared with and without flow conditioning

3 History of Caldon meters 1965 LEFM (Leading Edge Flow Meter) ultrasonic technology is developed by Westinghouse Electric Corporation 1971 Patent granted to Westinghouse for the first chordal multipath meter design using Gaussian integration

4 History of Caldon meters 1975 Nuclear Industry Prairie Island unit 2 PWR Primary reactor coolant loop, 30-inch 4-path meter

5 History of Caldon meters 1976 Petroleum Industry LEFM s installed on the TransAlaska pipeline 23 off 48-inch, 4-path meters

6 History of Caldon meters 1989 LEFM technology acquired by Caldon Inc. Primary focus on applications in the nuclear industry 1999 New line of petroleum products launched, designed specifically to meet the requirements for custody transfer 8-path liquid meters added to range

7 Chordal path design Gaussian Integration Johann Carl Friedrich Gauss ( ) General mathematical technique for accurately integrating a function with a limited number of inputs Does not assume fully developed or symmetrical flow Does not rely on empirical modelling or CFD analysis of a limited number of conditions

8 If it s that good why are flow conditioners used?

9 Only single paths are used at each chord location

10 Westinghouse patents filed 1968, 1975

11 British Gas (BG) patent filed 1986

12 To obtain the full benefits of the Gaussian integration technique, additional paths are required

13 Caldon 8-path design

14 The effects of swirl Non-axial flow components (swirl) result in systematic errors in individual path velocities Upstream transducer Downstream transducer Actual velocity Transverse component (unwanted) Axial component (wanted) Measured velocity

15 Swirl When dealing with non-axial flow we also have to consider the path orientation Upstream transducer Downstream transducer + -

16 Swirl Crisscrossed paths behave differently to parallel paths Upstream transducer Downstream transducer + +

17 Swirl With single plane or criss-crossing arrangements, swirl only cancels when perfectly centred Upstream transducer Downstream transducer + + -

18 4-path, planar (Westinghouse) configuration With a planar arrangement, swirl only cancels when perfectly centred Upstream transducer Downstream transducer

19 4-path, planar (Westinghouse) configuration Normalised velocity Profile without swirl path meter (single-plane) Path radial position 60 degree path angle, swirl error = 0.45 %

20 4-path, non-planar (BG) configuration In this case swirl cancelation relies on combination of dissimilar chords Upstream transducer Downstream transducer + Offset +

21 4-path, non-planar (BG) configuration 1.10 Normalised velocity Profile without swirl 4-path criss-crossed meter Path radial position degree path angle, swirl error = % + -

22 Eight-path Caldon 280Ci (liquid) / 380Ci (gas) Designed for swirl immunity Flow conditioning not required

23 How the crossed paths work Two crossing paths are placed precisely in each chordal plane - + Paths 1 and

24 How the crossed paths work Path 1 Key: Path 5 Path 1 + Path 5 Actual velocity Axial component (wanted) Transverse component (unwanted) Measured velocity Path 1 + Path 5 2 =

25 Eight-path crossed plane design 1.10 Normalised velocity path meter Paths 1 to Paths 5 to Path radial position Swirl error = 0 %

26 Is it better to use a 4-path meter with a flow conditioner or an 8-path design to reduce the effects of swirl?

27 Flow conditioners can become blocked

28 Flow conditioners If well maintained or protected by a filter flow conditioners reduce swirl and asymmetry but do not completely eliminate it To demonstrate this I will refer to two very well known sets of ultrasonic meter industry sponsored research data

29 Gas Research Institute SwRi, USA 4, 5 and 6 path meters meters tested downstream of bends, with and without flow conditioning Results below for 5D CPA 10D between bends and meter, flow weighted mean error relative to straight pipe calibration 0.3 % 10D Daniel Instromet FMC Single Elbow % Elbows in-plane % Elbows out-of-plane

30 GERG European consortium test results Tests of three meters with bends and flow conditioners, flow weighted mean additional error 4-Path Chordal 6-Path Chordal 5-Path Reflecting

31 Additional features of the Caldon design Unique transducer arrangement Internal coating

32 Caldon transducer experience Many years of operation in nuclear applications at up to +235 deg C LNG applications at -161 deg C

33 Transducers removable from pressure retaining titanium housings in meter body no blow down or special extractor tools required Manifold Removal Transducer configuration

34 Adhesion resistant proprietary coating Meter body and the transducer housings are coated to aid preservation of calibration conditions

35 Is it better to use a 4-path meter with a flow conditioner or an 8-path design to reduce the effects of swirl? TEST RESULTS

36 Installation effect testing 8-path full-bore Caldon LEFM 380Ci gas flow meter 12-inch meter Tests performed at CEESI Iowa Part of the overall suite of tests the meter has been undergoing to demonstrate compliance with ISO, AGA and OIML standards

37 Installation effect testing All tests witnessed by NMi of the Netherlands 8-path meter performed in compliance with OIML 0.5 class performance without requiring a flow conditioner Results presented here for single and double bends, with and without flow conditioning

38 Installation changes for each disturbance 5D 15D CPA

39 Results and analysis 8-path data can also be broken down into four different 4-path arrangements 8-path Plane A Plane B BG 1 BG 2

40 Straight pipe baseline

41 Straight pipe baseline, flow diagnostics Axial velocity profile Transverse flow (swirl) &5 0.6 Paths 1-4 Path height 0.4 Paths &6 8-path profile % swirl & & Normalised velocity % -20% -15% -10% -5% 0% 5% 10% 15% 20% 25% Transverse flow velocity

42 5D, double bend, paths horizontal

43 5D, double bend, horiz, flow diagnostics Axial velocity profile Transverse flow (swirl) &5 0.6 Paths 1-4 Path height 0.4 Paths &6 8-path profile % swirl & & Normalised velocity % -20% -15% -10% -5% 0% 5% 10% 15% 20% 25% Transverse flow velocity

44 5D, single bend, paths horizontal

45 5D, single bend, horiz, flow diagnostics Axial velocity profile Transverse flow (swirl) &5 0.6 Paths 1-4 Path height 0.4 Paths &6 8-path profile & & Normalised velocity % -20% -15% -10% -5% 0% 5% 10% 15% 20% 25% Transverse flow velocity

46 5D results

47 5D results, no FC, 8-path meter Straight pipe 1.2 Double bends out-of-plane, paths horizontal 1.0 Double bends out-of-plane, paths vertical 0.8 Single bend, paths horizontal 0.6 Single bend, paths vertical Error (%) Meets AGA and ISO requirement, additional errors less than +/- 0.3% Velocity (m/s)

48 5D results, no FC, 4-path non-planar, BG Error (%) Straight pipe Double bends out-of-plane, paths vertical Single bend, paths vertical Double bends out-of-plane, paths horizontal Single bend, paths horizontal Fails AGA and ISO requirement, additional errors less than +/- 0.3% Velocity (m/s)

49 15D, double bend, paths horizontal

50 15D, double bend, horiz, flow diagnostics Axial velocity profile Transverse flow (swirl) &5 0.6 Paths 1-4 Path height 0.4 Paths &6 8-path profile 0.0 9% swirl & & Normalised velocity % -20% -15% -10% -5% 0% 5% 10% 15% 20% 25% Transverse flow velocity

51 15D results

52 15D results, no FC, 8-path meter Straight pipe 1.2 Double bends out-of-plane, paths horizontal 1.0 Double bends out-of-plane, paths vertical 0.8 Single bend, paths horizontal 0.6 Single bend, paths vertical Error (%) Meets AGA and ISO requirement, additional errors less than +/- 0.3% Velocity (m/s)

53 15D results, no FC, 4-path non-planar, BG Straight pipe Double bends out-of-plane, paths horizontal Double bends out-of-plane, paths vertical Single bend, paths horizontal Single bend, paths vertical Error (%) Fails AGA and ISO requirement, additional errors less than +/- 0.3% Velocity (m/s)

54 Double bend, 5D CPA 10D

55 5D-CPA-10D, dbl bend, flow diagnostics Axial velocity profile Transverse flow (swirl) &5 0.6 Paths 1-4 Path height 0.4 Paths &6 8-path profile % swirl & & Normalised velocity % -20% -15% -10% -5% 0% 5% 10% 15% 20% 25% Transverse flow velocity

56 5D CPA 10D results

57 CPA FC results, 8-path meter Straight pipe 1.2 Double bends out-of-plane, paths horizontal 1.0 Double bends out-of-plane, paths vertical 0.8 Single bend, paths horizontal 0.6 Single bend, paths vertical Error (%) Meets AGA and ISO requirement, additional errors less than +/- 0.3% Velocity (m/s)

58 CPA FC results, 4-path non-planar, BG Straight pipe 1.2 Double bends out-of-plane, paths horizontal 1.0 Double bends out-of-plane, paths vertical 0.8 Single bend, paths horizontal 0.6 Single bend, paths vertical Error (%) Meets AGA and ISO requirement, additional errors less than +/- 0.3% Velocity (m/s)

59 Data Summary Presented in terms of the max additional error and the flow weighted mean additional error relative to the baseline calibration

60 Max additional error > qt Max Error Shift in 25% to 100% flow range Disturbance Upstream Single Bend 5D Double Bends Single Bend 15D Double Bends Single Bend 5D - CPA - 10D Double Bends Path orientation Horizontal Vertical Horizontal Vertical Horizontal Vertical Horizontal Vertical Horizontal Vertical Horizontal Vertical 8-path meter 0.09% 0.11% 0.09% 0.23% 0.10% 0.12% 0.11% 0.13% 0.04% 0.05% 0.07% 0.07% Planar 4-path (Westinghouse) A B 0.18% 0.24% 0.20% 0.09% 0.28% 0.18% 0.46% 0.19% 0.09% 0.16% 0.09% 0.14% 0.30% 0.17% 0.14% 0.13% 0.09% 0.07% 0.05% 0.12% 0.08% 0.14% 0.11% 0.22% Non-planar 4-path (British Gas) % 0.93% 0.88% 0.99% 1.30% 1.18% 0.49% 0.94% 0.32% 0.50% 0.67% 0.60% 0.17% 0.21% 0.23% 0.08% 0.12% 0.14% 0.19% 0.12% 0.13% 0.27% 0.17% 0.08%

61 Flow weighted mean error shift full flow range Flow Weighted Mean Error Shift Disturbance Upstream Single Bend 5D Double Bends Single Bend 15D Double Bends Single Bend 5D - CPA - 10D Double Bends Path orientation Horizontal Vertical Horizontal Vertical Horizontal Vertical Horizontal Vertical Horizontal Vertical Horizontal Vertical 8-path meter 0.06% 0.03% 0.02% -0.06% -0.08% -0.05% -0.05% -0.08% -0.02% -0.04% 0.03% 0.06% Planar 4-path (Westinghouse) A B -0.08% 0.21% 0.00% 0.07% -0.10% 0.15% -0.26% 0.14% -0.04% -0.13% -0.02% -0.08% -0.24% 0.13% -0.06% -0.11% -0.06% 0.02% -0.01% -0.07% -0.05% 0.11% -0.08% 0.20% Non-planar 4-path (British Gas) % -0.90% -0.86% 0.93% 1.17% -1.12% 0.45% -0.57% 0.30% -0.46% -0.61% 0.51% 0.09% -0.20% -0.12% -0.05% -0.12% 0.07% -0.14% 0.06% -0.11% 0.17% 0.12% 0.00%

62 Comparison with published reference data from GRI and GERG research projects

63 Downstream of bends no flow conditioners + 2%2 Flow weighted mean error (%) %-2 - Single bend Single bend, meter rotated 90 Double bends out-of-plane 5-path reflecting 10 D inlet Double bends, meter rotated 90 6-path chordal 10 D inlet GRI GERG 4-path chordal 10 D inlet CEESI/NMi Caldon 8-path 5 D inlet GRI GERG GRI GERG

64 Other meters with CPA plate vs 8-path without + 1%1 Flow weighted mean error (%) % - Single bend Single bend, meter rotated 90 4-path chordal CPA plate Double bends out-of-plane Double bends out-of-plane rotated 90 5-path reflecting CPA plate 6-path chordal CPA plate CEESI/NMi GRI GERG CALDON 8-path 5 D inlet no FC GRI GERG GRI GERG

65 Conclusions 4-path meters require flow conditioning to ensure they meet the ISO, AGA and OIML Class 1.0 requirements downstream of bends The 8-path meter meets the more demanding OIML Class 0.5, ISO and AGA requirements downstream of bends with 5D and no flow conditioner

66 Conclusions Comparing like for like installation conditions, the installation effects for the 8path meter are typically between 3 and 5 times lower than that for the 4-path meters Moving the 8-path meter from 5D to 15D and then adding the flow conditioner reduces slightly the maximum error shifts, but has little effect on the weighted mean error shift

67 Conclusions As the errors for the 8-path with no conditioner are smaller than typically obtained with 4, 5 and 6-path meters even when a flow conditioner is used, these results can be taken as positive confirmation of the ability of the 8-path meter to improve on past expectations of custody transfer performance with the added benefit of not requiring a flow conditioner