steam quality measurement methods using prowirl e&h meter

08/27/2014

Products Solutions Services

Got Steam?

New Techniques for Measuring Steam Quality in Utilities

Slide 1 Adam Battinieri

08/27/2014

Got Steam? New Techniques for Measuring Steam Quality in Utilities

How does steam safety impact you?

Adam Battinieri Slide 2

PresenterPresentation NotesSteam may be one of the most SAFETY critical parts of the plant. If you do not measure it, you can not control it. A typical boiler has very basic instrumentation. Making the boiler operation more efficient and more safe should be the goal of any plant that owns a boiler. Proper instrumentation on and around the boiler can improve the efficiency and save the customer money and make the operation of the boiler more safe.

08/27/2014


What we dont measure- we cant control


What is Wet Steam?

Do you know the quality of your Steam?

100% steam quality

80% steam quality

PresenterPresentation NotesSome words that will be used and interchanged through out the presentation. Dryness fraction = Steam quality define what dryness fraction is, mass of vapor/total mass(liquid+vapor) or the % mass of the vapor presentLiquid=condensate=waterVapor= steamSome questions to get people to think about how well they understand and know their steam process.

Do you know how much liquid phase is present?Are you aware of the dangers of Wet Steam?The inefficiency of wet steam?The money it costs to produce wet steam?The energy available in wet vs. dry steam?

08/27/2014


How do you measure steam quality?


3 Components: Pressure Temperature Amount of liquid (condensate)

PresenterPresentation NotesMost steam measurement devices today measure pressure, temperature, and flow of steam. They do not measure or account for the amount of condensate present. A misconception customers have about steam is they can derive the quality/dryness fraction of steam by measuring the pressure and temperature. This is false, in order to measure steam quality/dryness fraction, three compenents are required: Pressure, Temperature, and the amount of condensate present. It is easy for E+H and other instrument manufactures to measure pressure and temperature, the difficult measurement is the amount of condensate in their steam. The Boiling water reminds people that although the water is boiling at 100 deg C and at atmospheric pressure, the entire pot does not immediately vaporize as soon as the water becomes 100 deg C @ atm. Instead we have liquid present and steam present at saturation pressure and temperature. Water hits 100 deg C and then requires Energy,40kj/mol ,to convert the water to steam.

08/27/2014


Where am I on the steam curve?


PresenterPresentation NotesThe black and white steam curve is meant to show the different regions of the steam curve; water, wet steam, dry saturated steam, superheated steam. In addition, the energy required to increase the temperature from A to B and then the additional energy required to convert the wet steam to dry saturated.The colored slide highlights how temperature and pressure remain constant at you move from saturated water to 0.2,0.4,0.6,0.8,0.9 and finally 1 = dry saturated steam. By just measuring pressure and temperature you do not know if you are 0.2, 0.8 dryness fraction, there is no difference in pressure and temperature. You need to measure the third component, the amount of condensate in order to measure dryness fraction/steam quality.

08/27/2014


What is Dryness Fraction


Mass Fraction vs. Volume Fraction Quality is the % mass that is vapor

Quality = 1 Saturated Vapor Quality = 0 Saturated Liquid

PresenterPresentation NotesA quality of 1 means dry saturated steam, a quality of 0 means you have saturated liquid. 1 mean 100% in the vapor phase; 0 means 100% in the liquid phase.We can visualize volume. We know what a half empty glass looks like. Volume is easy for us to visualize. Mass on the other hand can be more difficult to visualize. Dryness Fraction is a mass term. Meaning dryness fraction or quality is the mass % that is vapor. A dryness fraction of 0.9 means that 90% of the mass is vapor and 10% of the mass is liquid. This can be difficult to visualize how much water is present. We are trying to get energy out of steam and the best way to calculate the available energy in the steam is to know how much of the mass is liquid and how much of the mass is steam.

08/27/2014


Application Example Why dryness fraction is a mass term


Low Pressure Steam: Steam Quality 90% In volume terms: 99.9% of the volume is Vapor

Low Pressure Steam: Steam Quality 10% In volume terms: 98.9% of the Volume is Vapor

Conclusion: 90% steam quality to 10% steam quality has a volume difference of 1% resulting in a 340% difference in Energy

PresenterPresentation NotesThis example is meant to highlight the large swing in dryness fraction (mass) vs. the very small difference in volume. A steam quality (dryness fraction) change from 0.9 to 0.1 has a liquid volume difference of 1% and the energy difference in the above example of 0.9 to 0.1 dryness fraction is 340%

Low Pressure Steam: Steam Quality 0.92 Bar_a; 120 deg C; 0.9 steam quality 90% of the mass is vapor, 10% of the mass is liquid In volume terms: 99.9% of the volume is Vapor, 0.1% is liquid

Low Pressure Steam: 2 Bar_a; 120 deg C; Steam Quality 0.110% of the mass is vapor, 90% of the mass is liquidIn volume terms: 98.9% of the Volume is Vapor, 1.1% is liquid

Conclusion: 90% steam quality to 10% steam quality has a volume difference of 1% resulting in a 340% difference in Energy

08/27/2014


Dangers of Wet Steam


Water Hammer

Erode control valves

Premature failure of steam system

PresenterPresentation NotesIn addition to the inefficiencies associated with wet steam, it can also be dangerous. Water hammer picture shows slip yanked from 8 expansion joint by condensate induced water hammer that broke the supporting anchors.Erode control valve this 8 class 250 valve ruptured while being opened to 220 psig steam.

Premature failure of steam system video showing a street in Manhattan NYC where a steam line burst do to wet steam and water hammer over time made the piping burst.

08/27/2014

Impact: Supplying values you need

NEW direct 4-20mA input allows temperature and pressure

correction with an output format a customer desires



Direct Mass and Energy

PresenterPresentation NotesWe now offer an easy way to measure the pressure with a direct 4-20mA and temperature with an integral pt1000 rtd in the sensor body of the vortex. So what are we missing??? Wait! Next slide!

08/27/2014


Impact: Poor steam quality - expanded


Dryness fraction

PresenterPresentation NotesAmplitude variation/deviation over time can be analyzed and with the patented function of the curtosis a correlation to the steam quality can be found.

Condensate flow is instationary (condensate is flowing in waves) DSC-Sensor paddle can regularly be covered by condensate, but will also be uncovered in regularly.

Horse shoe vortex (Hufeisenwirbel) Zeitliche Verzgerung auf Video

08/27/2014


Value: Steam quality energy correction


PresenterPresentation NotesProportional error between mass flow accuracy and steam quality

08/27/2014


Prowirl 200 is optimized for steam measurement

Slide 12

IAPWS - table

Mass and energy compensation for wet/saturated and superheated steam

Compensation with temperature and pressure (fixed or dynamic)

The International Association for the Properties of Water and Steam

PresenterPresentation NotesSteam table built in, vortex meter automatically navigates from wet steam, dry saturated, and superheated because it is able to measure all three compenents. Customer no longer has to select saturated or superheated, he just selects STEAM and the meter knows where it is on the graph

08/27/2014

Causes of Wet Steam Got Steam? New Techniques for Measuring Steam Quality in Utilities


PresenterPresentation NotesSo your meter is telling you that you have wet steam, here are some ways to improve your steam quality.

08/27/2014

Application example: How improving steam quality impacts the bottom line

Improving your steam quality from 0.8 to 0.95 on a 13000 lb/hr Boiler How Much Money does improving my Steam quality from 0.8 to 0.95 save?

95k/year



95% steam quality

80% steam quality

95% steam quality

PresenterPresentation NotesI did the improvements and I went from 0.8 to 0.95 and it saved me 95K per year in energy cost.Improving your steam quality from 0.8 to 0.95 on a 13000 lb/hr BoilerBoiler operates at 145 PSIA, 355 deg F. Boiler Feedwater is 194 deg FNatural Gas Cost $4.02/MMBTUBoiler operates 24/365

08/27/2014

Application Example: Measuring in Mass vs. Energy

How much are you being over charged if the steam you are receiving is 0.9 dryness fraction?

Utility bill will be 8% higher than it should be



PresenterPresentation NotesThe message from this slide is why we should be measuring steam in energy terms and not mass. The customer is paying for the energy of Dry saturated steam, he may be getting over or under billed for his steam usage.

If you are being billed for steam usage, you are paying to dry saturated steam. How much are you being over charged if the steam you are receiving is 0.9 dryness fraction?Boiler operates at 145 PSIA, 355 deg FUtility bill will be 8% higher than it should be

08/27/2014


What have we learned?

Boilerhouse, Marstons Brewery, UK

Your meter is wrong!!


PresenterPresentation NotesBreweries rely heavily on the reactions from steam to produce top quality wort used in the beer making process.

A common complaint is the 'meter' or 'measurement technology' is the fault. Let's look at the application in a little more detail.

08/27/2014

Brewery Flow Measurement Got Steam? New Techniques for Measuring Steam Quality in Utilities

FT 8017

FT 8023

Fuel

FT 03

FT 01

FT 8022

Blow

dow

n

FT 02

Air

Feed water tank

FT 8016

FT8023 Saturated Steam

P = 8.5 bara / 123psi T = 173C / 343F

Q_m = 4.6t/h DN 100

FT8017 Saturated Steam T = 155C / 311F

Q = 2.4t/h DN 80

FT8022 Saturated Steam T = 155C / 311F

Q = 2.4t/h DN 80

FT8016 Saturated Steam

No insulation T = 173C / 343F

Q = 1.55t/h DN 80

L = 300 m Q_loss = 182kW

Q_m_cond. = 0.32t/h

FT 01 Combustion Air

P = 1bara / 15psi T = 20C / 68F Q = 13.650t/h

DN 250 V = 61.8m/s

FT 02 Fuel Oil (Middle) P = 2bara / 29psi

T = 25C / 77F Q = 0.785t/h

DN 8 V = 4.3m/s

= 913.31kg/m = 121.8cP

FT 03 Feed Water

DN 40 V = 2.6m/s


PresenterPresentation NotesPlease click on the different FT for process detailsThe main boiler output is shared between three common flow headers leading to the process vessels. The sum of these three sub metering points should total AND match the output of the main boiler output meter, right?

08/27/2014

Your flowmeter is wrong! Got Steam? New Techniques for Measuring Steam Quality in Utilities

Comparison of boiler outlet and sub-meters: FT8023 (Boiler outlet): 4.6t/h Sum of FT8017, FT8022 and FT8016: 2.4t/h + 2.4t/h + 1.55t/h = 6.35 t/h

Deviation of 38%

Reason: Prowirl 73


PresenterPresentation NotesSuperheated steam from the pressure drop across the control valves. Solution was to add a pressure transmitter with the Prowirl 200 integral temperature and wet steam measurementThe totals of the three sub meters was off by 38%!

Why? An uncompensated flow device - which does not take into account both pressure and temperature is likely to miss a key process effect which occurs in many steam systems today.

Superheated steam occurs from the pressure drop across each control valve - in fact each point where a pressure reduction occurs in the piping system. This could be a tee, reducer, on/off valve, etc.

The correct solution is to measure flow rate in mass, add temperature and pressure, and calculate the wet steam effect present in the steam system.

08/27/2014


What is your boiler operation & efficiency plan?


PresenterPresentation NotesLets not forget all of the relevant measurement points you can use in the boiler house to maximize performance and protect your investment.

(or 'We hope this little primer of steam measurement can help you manage the steam within your plant more effectively.

We didn't touch on all areas you might be able to focus on boiler operation efficiency, quality and safety - as well.')

Boiler temperatureBoiler pressureBoiler feed water temperatureBoiler feed water levelBoiler feed water flowBoiler feed water conductivity and pH (control blow down), Hydrazine, phosphateHow much steam flow leaves the boiler? At what quality?

Classification: Public

Slide 20

Thank you very much for your attention

Got Steam?How does steam safety impact you?What we dont measure- we cant controlHow do you measure steam quality?Where am I on the steam curve?What is Dryness FractionApplication Example Why dryness fraction is a mass termDangers of Wet SteamImpact: Supplying values you needImpact: Poor steam quality - expandedValue: Steam quality energy correctionProwirl 200 is optimized for steam measurement Causes of Wet SteamApplication example: How improving steam quality impacts the bottom lineApplication Example: Measuring in Mass vs. EnergyWhat have we learned?Brewery Flow MeasurementYour flowmeter is wrong!What is your boiler operation & efficiency plan?Thank you very muchfor your attention

steam quality measurement methods using prowirl e&h meter

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