Pitot tube deltaflow an engineering approach

Transcription

1 Pitot tube deltaflow an engineering approach systec Controls Meß- und Regeltechnik GmbH Thomas Gräber, Sales Manager

2 Principles of dp-measurement - The sum of c kinetic + potential Energy is constant (= law of conservation of energy) - dp-measurement: transformation of potential energy (pressure) into kinetic Energy (velocity) EPot EKin const

3 Principles of dp-measurement

4 Principles of dp-measurement Orifice: In the neck, velocity increases (kinetic E increases) and pressure decreases (potential E decreases)

5 Principles of dp-measurement Orifice Nozzels Venturi

6 Principles of dp-measurement Integrating pitot tube: At the impact point of the probe, the velocity is zero (cinetic E decreases) an the pressure raises (potential E increases)

7 Principles of dp-measurement qm d ² 2 dp C Flow Equation of EN ISO pges dp pstat u 1 qm d ² 2 dp 4 Flow Equation of deltaflow

8 Principles of dp-measurement qm d ² 2 dp C C ß dp qm 1 d ² 2 dp 4 Flow factor, depending on dimensions and Reynolds Diameter ratio d/d blockage factor expansion factor (takes densitiy variations in account) differential pressure denistiy at working conditions

9 Flow equation for liquids qm C 1 4 d ² 2 dp 4 1 qm d ² 2 dp 4 When measuring liquids, the equation is less complicated: =1, C and are almost constant ß, d and are constant qm K dp mit K C 1 4 d 4 2 bzw. K 1 d

10 The effect of C and qm C 1 4 d ² 2 dp 4 C 1 qm d ² 2 dp 4 1 The term 1 is similar to the deltaflow term These are factors, which have been developed by experiments The blockage factor is from Re=8000 constant 4 C is a function of Reynolds (Re) and depend on flow exampel: orifice; DN 200; ß=0,5 deltaflow, DN200 Re= , C=0,6056 Re= , =2,4093 Re= , C=0,6032 Re= , =2,4093 Error in C= 0,4% Error in =0,0% For big flow spans, the Re-impact on C must be compensated!

11 The effect of 1 qm d ² 2 dp qm d ² 2 dp C Due to the pressure loss at the primary element, density of compressible fluids change. That has an influence on the flow measurement which is compensated by. For incompressible fluids: =1 Exampel: Air, 20 C, 1bar 200 Nm³/h 2000 Nm³/h Change Orifice; DN200; ß=0,6 =0,9999 =0,9844 1,55% deltaflow =1,0000 =0,9984 0,16% For big flow spans, the impact of must be compensated!

12 Pressure loss of primary devices (see VDI/VDE Druckverlust [% von dp] 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Blende Düse Venturi Bleibender Druckverlust [% von dp] 50% 40% deltaflow 30% 20% 10% 0% 0,2 0,3 0,4 0,5 beta [-] 0,6 0, Durchmesser [mm] High pressure steam example ID 250, 185bar, 540 C, 550 t/h deltaflow beta dp 2011 mbar Pressure loss 169 mbar cost (3 cent /kwh) EUR/p.a Venturi-nozzle 0, mbar 299 mbar EUR/p.a orifice 0, mbar 1111 mbar EUR/p.a 10000

13 Energy savings by small pressure losses deltaflow is only a small restriction in the pipe! Orifices create a tremendus pressureloss

14 Strength and weakness Price 3 Price 8 Price 20 Price High Pres. Applications Installation costs Accuracy Span Pressure loss Dirty fluids Small flow measurement Influence of Expansion Influence of discharge coeffizient Orifice Nozzel Venturi + O O -O O O + - O ---O O + O + deltaflow O/+ (DF10M)

15 Flow optimised profile Research co-operation with the University of Erlangen Certificate by PTB (PTB is Germany's highest authority when it comes to correct and reliable measurements. It is the supreme technical authority of the Federal Ministry for Economic Affairs and Energy

16 Flow optimised profile High Flow Velocity qm Low Flow Velocity 1 d ² 2 dp 4 Blockage factor depends on Reynolds (velocity)! -> Traditional profiles: Drift

17 Flow optimised profile Speed-up curve Smooth impact -> defined break-off point, no drift Sharp edges The medium passes the smooth impact zone and speeds up 3 times it s velocity to the sharp edges. Result: defined separation point, no drift Result: accuracy <0,5% for Re>8000, drift-free, tested by PTB

18 Patented Manufacturing Process 1. welding 2. milling +/- 0,5mm -> Traditional manufacturing: weak tolerances 3. grinding Result: tolerance up to 1mm 1 qm d ² 2 dp 4 Blockage factor depends on width of probe (a production tolerance of just 1mm at a pipe size of 100mm can cause a measurement error of 5% )

19 Patented Manufacturing Process deltaflow is robot welded in the uncritical speed up curves tolerance: < 0,025mm! The width of the probe is well defined by the precision rolling of the profile

20 deltaflow: Advantages Patented flow profile drift-free design Patented manufacturing process 8mm dp tappings (Insensitive on dust) Kapillary free construcion (Free drain of condensate, gas bubbles) Integrated temperature- and pressure measurement possible Maintenance-free Low pressure loss (compared to classical dp-elements) Reduced installation time (up to 90% comp. to classical dp-el.) Flexible Configuration (1mm 15000mm, 690bar, >1000 C) low acquisition costs

21 deltaflow: Advantages Narrowing orifice Narrowing Venturi Extreme less pressure loss with deltaflow

22 deltaflow: Advantages Less pressure loss: orifice 180 bar/a 550 C 76 kg/s DN 250 orifice diameter 170mm dp: 112,4 kpa pressure loss: 113,60 kpa deltaflow 180 bar/a 550 C 76 kg/s DN 250 dp: 41,48 kpa pressure loss: 3,36 kpa

23 deltaflow: Advantages Less power loss power loss = flow : density x pressure loss Density: 53,48 kg/m3 orifice 76 kg/s x 113,60 kpa 53,48 kg/m3 power loss: kw deltaflow 76 kg/s x 3,36 kpa 53,48 kg/m3 power loss: 4,77 kw

24 deltaflow: Advantages Extrem energy saving Orifice deltaflow Annual energy costs: kw x 8000h = MWh Annual energy costs: 4,77 kw x 8000h = MWh Average annual energy saving: 1253 MWh (80EUR/MWh = 100,243 EUR/a) + less operational demands of generators + less emission of CO2- lower costs (fees) for certificates

25 deltaflow: Advantages Shorter inlet requirements (1) -> less expenses for tubing deltaflow can already be mounted after 7D

26 deltaflow: Advantages deltaflow: ImproveIT data base with calibration factors (ca. 3000!) for short inlets

27 Straight run requirements

28 Straight run requirements - ImproveIT ImproveIT is a data base which offers calibration factors for typical obstacles in inlet (curves) Factors are provided by systec on request Factors can be put into deltacalc

29 Design your deltaflow deltaflow series DF8 DF12 DF25 DF25HDD3 DF25 Quicklok DF44 Type Pipe Size Pressure Remarks DF8 1-25mm 0-690bar Spool piece with integrated orifice DF10 DN20-DN bar Basically replaced by DF12 DF12 DN20-DN bar DF25 DN65-DN PN160 (PN250) DF25 Quick-lock DN65-DN bar DF44 200mm-15m 0-100bar DF25HDD bar 0-690bar Retractable weld-in (high-pressure)

30 Design your deltaflow required parameters (1) dp-connection Stud (e.g. cut ring or flange) Profile crosses whole diameter -> length customized to application Insulation IT WT Internal Diameter ID Wall thickness WT Thickness of isolation IT ID Profile are required

31 Design your deltaflow required parameters (2) Material Designation (SS316Ti) Stainless Steel, Standard Material (>>90% of all applications), up to 500 C High-temperature applications (up to 1040 C) , Hastelloy C4, Haynes Alloy corrosive media High-pressue See seperate chapter In most cases neck and parts outside of the pipe can be made of standard SS316 (1.4571) also when profile is made of special material Material of weld-in stud should be equal or similar to pipe material

32 Calculate (design) your deltaflow calculation software deltacalc?..\..\..\..\..\program Files (x86)\systec Controls\DeltaCalc 8 Web\deltacalc8web.exe

33 Design your deltaflow Required dp deltaflow requires a minimum differential pressure to ensure reliable measurement: As rule of thumb you should have at least: Gases / Liquids: Qmin Steam: >5mbar (steam applications are more sensitive against misinstallation than gas / Qmin dp s can be calculated for each application by using deltacalc software

34 Mounting Liquid Service Mounting should allow gas bubbles to vent off When installed sidewards probe should be slightly slanted (-3 0 )

35 Mounting Gas Service Mounting should allow condensate to drain back into pipe (Otherwise condensate might accumulate in internal piping and generate water column (which generates faulty dp)) When installed sidewards probe should be slightly slanted (0..3 )

36 Mounting Steam Service Condensate is used to transmit dp to transmitter Mounting should allow excessive condensate to drain back into pipe When installed sidewards probe should be slightly slanted (0..3 )

37 Mounting your deltaflow Lower mounting times and costs (-90%) Drilling installation hole 5 min Welding in flange stud 20 min Mounting deltaflow 10 min Mounting manifold 5 min Mounting dp transmitter 10 min Wiring 10 min Ready in 60 min!

38 Design your deltaflow required dp How can I handle low flows? Sometimes velocity is too low to provide sufficient dp values Spool Pieces with reduction can be used to speed up media Reduction Widening (e.g. DN65/DN100 (e.g. DN100/DN65) By using spool pieces with reduction deltaflow can serve also typical low flow applications (e.g. Biogas)

39 Opposite Support - Background Probe has a specific resonance frequency (RF) depending on length and width of probe Flow generates Vortex ( turbulence ) with a specific frequency (VF) at probe depending on velocity and width of probe ( probe is stimulated ) [RF and VF are mentioned at deltacalc calculation protocol] If Vortex frequency = resonance frequency (or multiple) probe might resonate and might break! Vortex To ensure mechanical stability an opposite support might be required

40 Frequency calculation without opposite support Application: Steam, DN200, 7bar, 200 C, various flows, without opposite support v=7.73m/s v=24.58m/s v=61.46m/s RF VF SF VF SF VF SF DF ,2 3,55 234,1 1,06 585,3 0,43 DF ,8 6,04 145,9 1,81 364,7 0,73 DF ,5 11,44 111,7 3,43 279,4 1,37 RF = Resonance Frequency of Probe / VF=Vortex Frequency Saftey Factor SF = RF/VF SF should be >= 1.3 to ensure mechanical stability

41 Frequency calculation with opposite support Application: Steam, DN200, 7bar, 200 C, various flows, with opposite support v=7.73m/s v=24.58m/s v=61.46m/s RF VF SF VF SF VF SF DF25 995,8 70,2 14,19 234,1 4,25 585,3 1,7 DF ,0 43,8 24,16 145,9 7,25 364,7 2,9 DF ,2 33,5 45,83 111,7 13,74 279,4 5,49 Opposite Support quadruples Resonance Frequency and Saftey! The bigger the profile the higher the resonance frequency

42 Opposite Support Examples DF25 prepared for use with (upper) and without (lower) opposite support High-pressure probe with opposite support

43 Opposite Support Summary / Design Rules Opposite Support Required if: Pipe Size >= DN1000 dp >= 20mbar and RF/VF <= 1.3 High-pressure probe Check (if required or not) is done automatically by deltacalc (except because of size!)

44 Integrated pressure/temperature measurement - background 1 qm d ² 2 dp 4 Density, depends on pressure (p) and Temperature (T) If pressure and/or temperature change, density also changes Density influences flow (e.g. T +10% -> density +10% -> q +srt(10%)=3.16% To compensate influence, p and/or T should be measured in order to calculate correct density (flowcom / multi variable transmitter) Only recommended/required when p and/or T fluctuate

45 Flowcomputer flowcom p&t compensation + Mass flow calculation Heat transfer measurement Data Logger + Display Easy handling (on-site with buttons)

46 Integrated pressure/temperature measurement Cable Box Integrated PT100 Presseure measurement (here: Steam Service) - Can be removed under pressurized conditions (600 C) - direct PT100 or 4 20mA (with transmitter) - Can be removed under pressurized Conditions (when having valve) - direct PT100 or 4 20mA

47 Integrated pressure/temperature measurement - Examples DF44 with preparation for external pressure transmitter (supplied by customer) (here: Liquid Service) DF12 with spool piece, integrated temperature measurement (Gas Service)

48 Integrated pressure/temperature measurement - Examples DF10 with integrated DF8 with preparation for temperature (Gas Service) pressure measurement (Gas Service) DF8 with preparation for pressure measurement (Steam Service)

49 Integrated pressure/temperature measurement Model Integrated pressure Integrated Temperature DF8 X X Integrated in spool piece DF10 X X Integrated in spool piece DF12 (x) (x) Only with spool piece DF25 X X X X DF25HDD3 DF44

50 dp-connection - 3-way-manifold direct + Easy setting of zero point by using by-pass + Shut-off of media (e.g. allows remove of transmitter) + high pressure / temperature (PN400) - Smaller internal piping -> not recommended for wet gases

51 Design your deltaflow - Mounting of dp-transmitter Direct Mounting Remote Mounting

52 Splitting Range Measurement How can I handle big measurement ranges? deltaflow offers a span of typically 1 to 1 to 10 in flow means 1 to 100 (!) in dp How does that influence my measurement? Example: dp_min = 2mbar / dp_max = 240mbar span dp-transmitter: 250mbar, uncertainty 0.1% (=0.25mbar) 0.25mbar at 2mbar means relative uncertainty of 12.5% With splitting range. e.g: 1. Transmitter: 0 20mbar 2. Transmitter: mbar

53 Design your deltaflow splitting range How can I realize a splitting range measurement? You need two (or more) (stacked) transmitters You need evaluation unit (e.g. flowcom or PCS) which decides which transmitter should be used (depending on dp) Connectors ( T-bone )

54 Splitting range - summary With splitting range up to 4 dp-transmitters can be used Span of and more can be realized (pay attention to mechanical stability)

55 Air purging system LSP Highly Polluted media might clog deltaflow s dp-tappings When dust-load >=50mg/m3 automatical cleaning is required systec offers automatic air purging system LSP for periodical cleaning LSP blows pressurized air into deltaflow pressure chambers

56 Air purging system LSP - Principle Valves: When purging connection to dptransmitter is closed and connection to pressurized air is open Connections for dp-impulse pipes (Ermeto, others on request) Connection for pressurized air (max. 6bar) dp-transmitter can be mounted directly on LSP by using mounting plate Purging is controlled by SPS. Frequency of purging as well as length of purging can be set by user

57 Air purging system LSP - Example deltaflow DF50 (old style), flange type Shut-off (ball valves) LSP with mounted dptransmitter Connected by impulse piping

58 Air purging system LSP - Summary With LSP measurements at high degrees of pollution (up to 200 g/m3 (!)) become possible During purging dp is hydraulically locked -> no lost of dpsignal during purging Option Signal holding available. Here, last value of dp before purging is holded electronically by SPS Direct mounting of dp-transmitter possible (on top of LSP) Pressurized Air required on site (max. 6 bar) Impulse piping required (LSP - deltaflow)

59 High pressure probe When do I need high pressure probe? Limits for standard DF25: PN160 (steam), PN250 (Liquids) Finally, it has to be determined by customer, but there are indications when to use high-pressure probe: When weld-in probe is required (e.g. sealings are not accepted) When pipe is made of high grade material (e.g. P91, 10CrMo 9 10))

60 High pressure probe For high pressure applications a special version of the DF25 (DF25HDD3) is available Condensate Pots (for steam only) Weld-in part ( neck) Profile Profile made of massive block (no welding seams) Material of Profile: Materials of weld-in parts: Double valves 16Mo3, 10CrMo 9 10, P91 Material of valves: 16Mo3, 10CrMo 9 10 opposite support always required

61 High pressure probe - Examples - Steam, 535 C, 190bar - spool piece - Profile: Weld-in part: P91 - Condensate Pots: P91 - Steam, 540 C, 100bar - Profile: Weld-in part: 10 CrMo Condensate Pots: 10 CroMo 9 10 (=1.7380)

62 High pressure probe Required certificates / testings Requirements are regulated by PED97/23/EG 16 Mo 3 (1.5415) 13CroMo44 (1.7335) 10CrMo9 10 (1.7380/1.7383) X20CrMoV12 1 (1.4922) X-Ray TÜV acceptance test (dye penetration, P91 (1.4903) X x x x x X x x x x x x x x hardness test, material identification check) Heat treatment Documentation incl. 3.2 certificate x

63 Calibration 1 qm d ² 2 dp 4 Formula for flow calculation During calibration flow, dp (at deltaflow), p, T are measured at different points Corrected Blockage Factor Zeta is extracted Corrected Zeta will be then used for your appliaction -> Improved accuracy (0.4%) Calibration can be done at PtB or at systec Spool Piece always required PtB or systec issue calibration certificate

64 Factory Certificate PtB Certificate

65 weld-in stud with Quicklock with DIN/ANSI flange chain (max PN16) retractable weld-in stud (max PN40) Quicklock with spindle (max PN100) retractable

66 -½ NPT female oval flanges DIN EN oval flanges on ball three way manifold valve on oval flanges ball valve R ½ shut off valve welding ends, SS

67 Design your deltaflow deltaflow types Flange-type Cut-Ring Type

68 Design your deltaflow deltaflow types Spool Piece Weld-in (DF25HDD3) Weld-in (DF12)

69 Design your deltaflow deltaflow types DF25 Quick-lock system allows mounting/extraction under pressurized conditions (max. 100bar) DF8 spool piece (block) with integrated orifice

70 deltaflow types - Summary DF8 DF12 DF25 Flange-stud X X Cut-Ring X X Weld-in X Quick-lock Spool Piece X DF25 HDD3 DF44 Remarks X Max. PN250 (PN160 for steam) Max. PN40 X o.r. X X X Max. 100bar X max DN250 (other o.r.) Note: Spool Pieces are available with welding ends or flanges

71 dp-connection Miscellaneous Fitting (e.g. Ermeto) for remote mounting Ball Valve with fitting (e.g. Ermeto) for remote mounting Welding Ends for remote mounting Oval Adapter (direct mounting) (acc. to EN61518)

72 dp-connection Miscellaneous (2) Weather Protection Box + provides heating and protection for electrical equipment (transmitters) + Can be mounted remotley or direct on deltaflow s flange

73 deltaflow vs. Vortex + Large span (nominell 1 30/40) + compact + price (DN100, ca ) + accuracy (like deltaflow) - Max. DN250-DN400, max. 250 C-400 C, max. 100 bar (typical) - spool piece required (cut-off of pipe -> mounting costs) - High-pressure loss -> real span comparable to deltaflow - Long straight run required (min. 20xD) - very sensitive (twice as deltaflow) against p/t fluctuations (when not compensated)

74 deltaflow vs. magnetic-inductive flowmeter + price (DN300, ca ) + accuracy (0.5% (cutting-edge meters) - big diameters - Only liquids can be measured - Liquid must be electrically conductible - e.g. works not for desalinated water (cooling water) - Not recommended for hot-water (disposal of magnetite at electrodes -> drift)

75 deltaflow vs. thermal mass flow + big span (1 100) + suited for low flow + gives mass flow + cheap (starts at 200 for low quality) - Decreasing accuracy at higher velocities - Sensitive / highly sensitive (low cost) against condensate, (oil) films - Single point measurement (deltaflow: averaging) - Limited accuracy (2% for cutting-edge meters typical 10% for low cost.

76 deltaflow vs. mechanical flowmeters + cheap (starts at 300 ) + integrated flow indicator - Expensive at large diameters (typical limited to DN200) - Limited accuracy (5% of FS, most of cases worse) - moving mechanical parts subject to wear and tear - risk of drift caused by wear and tear (e.g. of bearings) - More an indication than measurement - Mounting costs: Rip up of pipe required

77 deltaflow vs. classical dp-elements (orifice) + cheap (orifice itself) + standardize (EN DIN5167) + widespread, accepted + self-made by some engineering companies - big diameters - High mounting cots (rip-up of pipe required - High pressure lost (see example below) -Long straight runs required (min. 15xD) High operational costs (energy loss) [calculation with systec spread-sheet possible)

78 Example 1: Powerplant deltaflow for steam with integrated p&t measurement

79 Example 1: Powerplant deltaflow for steam material P91 Pressure 285 bar/ü Temperature 565 C

80 Under Pressure deltaflow for natural gas PN320, 100% Humidity, protection box, Ex

81 Small Pipes deltaflow DF8 for steam

82 Chemistry deltaflow for process gas, Bayer AG, Hastelloy C4, 180 C, HCl, Ex

83 Waste Water Plants deltaflow for Biogas

84 Car manufacturers (and others) deltaflow for compressed air, integrated p&t-measurement, Daimler-Chrysler

85 Oil & Gas Industry deltaflow for natural gas, PN160, integrated p- and Tmeasurement, protection box, ex

86 Geothermal Power Plant (near Munich) 2 crossed deltaflows in spool piece (calibrated)

87 Under Pressure deltaflow for natural gas PN320, 100% Humidity, protection box, Ex

88 Chemistry deltaflow for process gas, Bayer AG, Hastelloy C4, 180 C, HCl, Ex

89 Emission Monitoring deltaflow for chimney, including. P, T, dp and flowcom in protection box

90 Municipalities deltaflow for hot water, bi-directional, splitting range Heat transfer measurement

91 Extraction systems - Allows installation / extraction under pressure - Rated up to 100 bar

92 Thank you for your attention