1 / 60

Steam and Water Sampling

Steam and Water Sampling. “Sampling 101” and Sample System Components. Utility Market Components. Back Pressure/Relief Valve - BPRV ™. Sample Coolers. Cation Resin Columns. Thermal Shut Off Valve - TSV ™. Variable Pressure Reducing Elements VREL ™. Steam and Water Sampling. Why sample?

aline-glover
Download Presentation

Steam and Water Sampling

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Steam and Water Sampling

  2. “Sampling 101” and Sample System Components

  3. Utility Market Components Back Pressure/Relief Valve - BPRV™ Sample Coolers Cation Resin Columns Thermal Shut Off Valve - TSV™ Variable Pressure Reducing Elements VREL™

  4. Steam and Water Sampling • Why sample? • Monitor/adjust water chemistry to: • Maximize heat transfer efficiency • Maximize time between chemical cleanings • Maximize boiler life and turbine life • Minimize operating & maintenance costs

  5. Typical Plant Diagram

  6. Typical Plant Diagram

  7. Important Sample Conditioning Parameters “The Primary objective of any sampling system is to transport and condition a sample without altering the characteristics of interest. The system parameters which need to be controlled are velocity, pressure and temperature.” Source: EPRI CS-5164, April 1987

  8. Sample Point Selection, CC System • Gas Turbine • Generators • Steam Turbine – Main Steam SiO2, Na, CC • HRSG – Boiler Drum - pH, SC, PO4, SiO2, Na, Chloride • Condenser – pH, SC, CC, Na, SiO2, DO • Feed water – SC, CC, Na, pH, SiO2 • Boiler Feed Pump • Not shown: • Deaerator – DO, pH, SC, CC • Economizer – pH, CC

  9. Sample Point Selection Based on: • System design • Subject constituents • Chemical treatment • System specific problems

  10. Sample Velocity • Velocity should be 5-6 ft/sec (1.8 m/sec) to maintain equilibrium of ionic and particulate components • Ideally, sample lines in sample system should be 1/4” (6.35mm) tube; flow rate at of about 1200 cc/min and velocity at 6 fps (1.8 m/s). • Flow rate of 3300 cc/min in a 3/8” (9.5mm) tube with .065” (1.65mm) wall is 6 fps

  11. Erosion/Deposition and Equilibrium

  12. Velocity –vs- Deposition

  13. Deposition –vs- Time

  14. Sample Lag Time Flow rate Velocity Tube Size cc/min Ft/sec Lag Time/1000’ 1/4”x.042” wall 500 2.5 6.5 min 12006.02.8 min 3/8”x.065”wall 500 0.9 18.7 min 1200 2.2 7.6 min 16663.05.6 min Theoretically correct > 3300 6.0 2.8 min But not practical 1/2”x.125 wall essentially equal to 3/8”x.065 wall 6.0 ft/sec is approximately 1.8 m/sec

  15. P&ID – Complete System

  16. Temperature Control – Primary Coolers • Primary sample cooler approach temperature: 5 ºF (2.8 ºC) of coolant temperature • Corrosion resistant tubing (18% Cr, 8% Ni), 316 SS, internal baffles • Coil tubing to meet velocity requirements (1/4”, 3/8” O.D.) (6.35mm, 9.5mm)

  17. Sample Coolers

  18. Sample Coolers

  19. Sample Coolers • High Efficiency, Counter Flow Design • All Stainless Steel Construction • Single Gasket Design • 100% Hydrostatic Testing, Tube and Shell • Variety of Shell and Tube Materials Available

  20. Standard Shellside Materials: • 316/316L Stainless Steel • 304 Stainless Steel • 90/10 CuproNickel Sample Coolers - Materials Standard Tubeside Materials: • 316/316L Stainless Steel • Alloy 625 (Inconel 625)

  21. Special Sample Coolers • Special sample coolers • Cooling water with elevated chlorides and DO such as cooling tower water or potable water sources • High temperature samples • Use Inconel 625 coils, CuNi shells

  22. Sample Coolers - Materials Optional Tubeside Materials, short coil only: • Alloy C-276 (Hastelloy) • Alloy 200 (Nickel) • Alloy 400 (Monel) • Titanium • Zirconium • 310SS Optional Shellside Materials: • 316/316L SS Additional materials may be possible. Orbitally welded long coils currently available in Zirconium

  23. Sample Coolers

  24. Competitive Products • Waters Equipment – USA • Dr Thedig - Germany • Forbes Marshall – India • Lowe – U.K. • DKK – Japan • Nikkiso – Japan/Taiwan • Eurosysteme • Watcom • Westhoff

  25. Competitive Products • Analyzer manufacturers • ABB • Yokagawa • Emerson • Swan • Others –local

  26. Competitive Products • May not offer performance calculations • Carbon steel shells • Thin wall shells (drawn) • May not offer dual baffle • Tie-rod designs • May offer dual-tube units which don’t work for ASTM recommended flows

  27. Important Sample Conditioning Parameters – Secondary Cooling • Secondary cooling • Recommended to control sample temperature to 77 °F +/- 1 °F (25 °C +/- .5 °C) • Analyzer temperature correction algorithms should be evaluated for: • Suitability given the expected sample matrix • Sample temperature range • Sensitivity • Potential correction factor error

  28. Important Sample Conditioning Parameters – Secondary Cooling • Isothermal Bath • Coils in chilled water bath • Chiller with hot gas bypass • Thermal bypass valves • Must have good mixing in bath • Bypass valves can be problematic

  29. Important Sample Conditioning Parameters – Secondary Cooling • Individual sample coolers • Individual, high efficiency coolers for each sample stream • Chilled water supply with hot gas bypass 75-76 °F +/- 1 °F (23.9 –24.4 °C) • Hot gas bypass can add heat into system if samples are sub cooled

  30. Important Sample Conditioning Parameters – Secondary Cooling • Field Study • 19 Fossil and Nuclear plants • 11 isothermal bath systems • 8 individual cooler systems • Isothermal baths averaged 77 °F +/- 5 °F ( 25 °C +/- 2.7 °C) • Max deviation 28 °F (15.6 °C) • Individual secondary coolers averaged 77 °F +/- 2 °F ( 25 °C +/- 1 °C) • Max deviation 5 °F (2.7 °C)

  31. Important Sample Conditioning Parameters • Pressure Reduction • All Wetted Parts Stainless Steel • Needle valves for 500 psig and less • Rod-in-tube for pressures greater than 500 psig • Drag valves and capillary tubes are prone to plugging • Adjustable rod-in-tube preferable • Cleanable in place • Adjust to proper flow

  32. Pressure ReductionVREL™ (Variable Pressure Reducing Element)

  33. VREL™

  34. VREL™

  35. Competitive Products • Look alike or similar rod-in-tube designs – may or may not operate well • Capillary tubes - plug • Drag valves – plug - expensive • Multiple needle valves – wear – same price as VREL

  36. Important Sample Conditioning Parameters • Flow Control • EPRI/ASTM recommends a Rod-in-tube pressure reducing device and backpressure valve combination • Constant sample velocity/flow • Reduced possibility of crud bursts • Constant flow to on-line analyzers for repeatable analysis results • BP/RV acts as a “shock absorber”

  37. Back Pressure Regulator/Relief Valve

  38. BP/RV • Assures Constant Pressure/Flow to Analyzers • Protects System From Over Pressurization • Large Orifice Won’t Plug or Stick • Constant Pressure Over Wide Flow Range • Regulates to 20 psi (standard) • Metallic Wetted Parts – Stainless Steel • Elastomer – Viton • Seat – PEEK • Optional pressure settings: 5 psig (0.3 barg), 7 psig (0.5 barg), 12 psig (0.8 barg), 28 psig (1.9 barg), 42 psig (2.9 barg), 60 psig (4.1 barg)

  39. BP/RV

  40. Back Pressure Regulator/Relief Valve

  41. Competitive Products • Tescom • Go • Coniflo • Not designed specifically for the application

  42. TSV(Thermal Shut Off Valve)

  43. Thermal Shut Off Valve (TSV) • Protects analyzer cells • Protects operators • Mechanically Actuated, Automatic Shut-Off for Thermal Protection • Visual Trip Indication • Optional Switch for Remote Indication • Requires Manual Reset • Latching Design • No Pneumatic or Electrical Power Required

  44. Competitive Products • Wax valves – automatically reset or are one use • Sensor, controller and solenoid valve – expensive – problematic • Bi-metal, mechanical or electro-mechanical – trip point is not accurate, prone to failure

  45. Thermal Shut Off Valve (TSV) • Standard Wetted Materials • 316 Stainlesss Steel, Viton, PEEK • Optional Elastomer • Kalrez • Standard Temperature Set Point = 120° F (49° C) • Optional Temperature Set Points = 104° F (40° C), 140° F (60° C), 160° F (71° C), 153° F (67° C), 194° F (90° C), 203° F (95° C), 210° F (99° C)

More Related