sentry sampling components

Sentry Equipment CorpSentry Equipment CorpSampling Solutions • Specialty Heat Sampling Solutions • Specialty Heat ExchangersExchangers

Steam and Water SamplingSteam and Water Sampling


““Sampling 101” and Sample Sampling 101” and Sample System ComponentsSystem Components


Utility Market ComponentsUtility Market Components

Thermal Thermal Shut Off Shut Off Valve - Valve - TSVTSV™™

Back Pressure/Relief Back Pressure/Relief Valve - BPRVValve - BPRV™™

Sample CoolersSample CoolersCation Resin Cation Resin

ColumnsColumns

Variable Pressure Variable Pressure Reducing ElementsReducing Elements

VRELVREL™™


Steam and Water SamplingSteam 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


Typical Plant DiagramTypical Plant Diagram


Important Sample Conditioning Important Sample Conditioning ParametersParameters

““The Primary objective of any sampling The Primary objective of any sampling system is to transport and condition a system is to transport and condition a

sample without altering the sample without altering the characteristics of interest. The system characteristics of interest. The system parameters which need to be controlled parameters which need to be controlled are are velocityvelocity, , pressurepressure and and temperaturetemperature.”.”

Source: EPRI CS-5164, April 1987


Sample Point Selection, CC Sample Point Selection, CC SystemSystem

1. Gas Turbine

2. Generators

3. Steam Turbine – Main Steam SiO2, Na, CC

4. HRSG – Boiler Drum - pH, SC, PO4, SiO2, Na, Chloride

5. Condenser – pH, SC, CC, Na, SiO2, DO

6. Feed water – SC, CC, Na, pH, SiO2

7. Boiler Feed Pump

Not shown:

Deaerator – DO, pH, SC, CC

Economizer – pH, CC


Sample Point SelectionSample Point SelectionBased on:

System design Subject constituents Chemical treatment System specific problems


Sample VelocitySample 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


Erosion/Deposition and EquilibriumErosion/Deposition and Equilibrium


Velocity –vs- DepositionVelocity –vs- Deposition


Deposition –vs- TimeDeposition –vs- Time


Sample Lag TimeSample Lag Time

Flow rate VelocityTube Size cc/min Ft/sec Lag Time/1000’1/4”x.042” wall 500 2.5 6.5 min

1200 6.0 2.8 min

3/8”x.065”wall 500 0.9 18.7 min1200 2.2 7.6 min1666 3.0 5.6 min

Theoretically correct > 3300 6.0 2.8 minBut not practical

1/2”x.125 wall essentially equal to 3/8”x.065 wall6.0 ft/sec is approximately 1.8 m/sec


P&ID – Complete SystemP&ID – Complete System


Temperature Control – Primary Temperature Control – Primary CoolersCoolers

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)


Sample CoolersSample 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



Sample Coolers - MaterialsSample Coolers - Materials

• 316/316L Stainless Steel• Alloy 625 (Inconel 625)

Standard Tubeside Materials:Standard Tubeside Materials:

Standard Shellside Materials:Standard Shellside Materials: 316/316L Stainless Steel 304 Stainless Steel 90/10 CuproNickel


• 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

Special Sample CoolersSpecial Sample Coolers


Sample Coolers - Sample Coolers - MaterialsMaterials

• Alloy C-276 (Hastelloy)• Alloy 200 (Nickel)• Alloy 400 (Monel)• Titanium• Zirconium• 310SS

Optional Tubeside Materials, short coil only:Optional Tubeside Materials, short coil only:

Optional Shellside Materials:Optional Shellside Materials:

Additional materials may be possible.

Orbitally welded long coils currently available in Zirconium

316/316L SS316/316L SS


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


Competitive ProductsCompetitive Products• Analyzer manufacturers

– ABB– Yokagawa– Emerson– Swan

• Others –local


Competitive ProductsCompetitive 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


Important Sample Conditioning Important Sample Conditioning Parameters – Secondary Parameters – Secondary

CoolingCoolingSecondary 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



CoolingCooling

Isothermal Bath– Coils in chilled water bath

Chiller with hot gas bypassThermal bypass valves

– Must have good mixing in bath– Bypass valves can be problematic



CoolingCooling

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



CoolingCoolingField 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)



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


Pressure ReductionPressure ReductionVRELVREL™™ (Variable Pressure Reducing Element) (Variable Pressure Reducing Element)


VRELVREL™™



• 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



• 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”


Back Pressure Regulator/Relief ValveBack Pressure Regulator/Relief Valve


BP/RVBP/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)


BP/RVBP/RV


Back Pressure Regulator/Relief ValveBack Pressure Regulator/Relief Valve



• Tescom• Go• Coniflo

– Not designed specifically for the application


TSVTSV(Thermal Shut Off Valve)(Thermal Shut Off Valve)


Thermal Shut Off Valve Thermal Shut Off Valve (TSV)(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



• 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


Thermal Shut Off Valve Thermal Shut Off Valve (TSV)(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)


Cation Resin ColumnCation Resin Column


Cation Resin ColumnCation Resin Column• Ion exchange resin uses porous beads that have a

Hydrogen ion that can be exchanged for a cation.• R = the resin and H = hydrogen ion• 2R-H +Ca+2 <=> R2-Ca +2H+

• The Resin column acts somewhat like a “filter”• Reduces the “masking” effect of ammonia• Proper length – dia. Ratio for good ion exchange• Prevents “channeling”• Refillable


• Major Cations in water– Ca+2

– Mg+2

– Na+

– Fe+2

– Cr+6

– Ni+3

– Cu+2

– Zn+2

– NH4+

Cation Resin ColumnCation Resin Column



• Many, varied• Resin is mostly the same but length to

diameter ratio is key to proper ion exchange

• A larger column may offer more resin but poorer ion exchange

• Tubes are usually thinner, poor quality


ASTM StandardsASTM Standards

ASTM 3370 – Standard Practices for sampling water from closed conduits

ASTM 5540 - Standard Practices for flow control and temperature control for On-Line water sampling and analysis

Shortcut to ASTMD5540.pdfASTM 1066 – Standard practices for sampling

steam

Note: ASTM 1192 – Similar to D5540 - suspended


ConclusionConclusion

“ A properly designed sample system transports and conditions samples from the point of extraction to analysis points without altering the characteristics of interest”


End Of Sampling End Of Sampling ComponentsComponents


Sample Line Fouling SolutionsSample Line Fouling Solutions

Strainer, high Strainer, high pressure and pressure and temperaturetemperature

Traditional sintered Traditional sintered element filter, low element filter, low temperaturetemperature


Sample Line Fouling SolutionsSample Line Fouling Solutions• Sludge trap

– Designed to “drop out” particles rather than trap them and hold them in the flow stream.

– Installed upstream of primary sample cooler

– Usually limited to boiler drum or similar samples

– Requires periodic flush to drain and piping to safe location (HP header, blow down tank)


Sample Line Fouling SolutionsSample Line Fouling Solutions

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