Training - Level

Level 1 - Fundamental Training

Level

Level 1 Fundamental Training

1

Level 1 - Level

Contents Topics: • Why measure level? • Level terminology • Technology selection • Technology (Pressure Transmitter, HTG & Hybrid System • Other Technology (Float, Capacitance, Displacer, Servo, Nucleonic, Laser & Ultrasound) • Exercise

2

Slide No: 3-5 6 - 19 20 - 29 30 - 55 56 - 75

76 - 80

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Level

Why measure level? 5 Common Reasons

3

Inventory • keep track of amount of material of material available for a process

Custody Transfer • amount of material that is bought & sold in terms of volume or weight

Effieciency • maximise storage tank capacity • preventing unnecessary expense of purchasing additional vessels

Safety • prevent spillage in open vessels • prevent overpressure conditions in closed vessels that may result in rupture

Consistent Supply • to maintain product quality in a process » blending, pulp & paper Level 1 - Level

Why measure level? Inventory vs. Process

4

Inventory • Accuracy is primary difference » better than 3 mm precision needed • Applications need precise measurement because of $$$$$ » Transfer of ownership » Exact quantity must be known » Product cost You can have a » Tend to be larger vessels mixture of process

Process

and inventory applications in a plant

• Applications are more concerned with: » Control of a product level within a range » Safety (prevent overflow/ pump shutoff) » Monitor inputs of components of a process » Accuracy requirements vary widely

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Why measure level? Indication vs. Control

5

Indication • on-site level check • operator interpret measurement ˆIndicators – open loop control system – help calibrate automatic control system Control • closed loop system ˆprocess ; point of measure ; transmitter ; controller ; control valve ; process

Level 1 - Level

Level terminology Level Control Loop

6

(Inflow) I/P

LIC

• Level Loop Issues: – Control At Inflow or Outflow – Non-Self Regulating

LT

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Level terminology Level Control Loop

7

(Outflow)

LIC

I/P

LT

Level 1 - Level

Level terminology Parameters

8

Interface Level

Volume Density

Mass Level 1 - Level

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Level terminology Parameters

9

Interface • Interface measurement finds the boundary between two liquids stored in the same tank » each liquid has different density Liquid A to air/vapor interface Liquid A Liquid A to B interface Liquid B

Level 1 - Level

Level terminology Parameters

10

Density • Density is a measure of the mass per volume Example: – grams / cc – pounds / cu ft • Specific Gravity is a ratio of the density of a Density fluid to the density of water, thus density of fluid density of water

= SG

Density of fluid = density of water * SG

Mass = Density / Volume Level 1 - Level

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Level terminology Parameters

11

Volume • Volume only correlates directly to level when: » Tank is an upright cylinder » Density is constant Volume » Temperature is constant » There is no change in tank wall position after filling • Volume measurements are in units such as: » gallons, liters, barrels... • Level measurements are in units such as: » inches, feet, millimeters, centimeters, meters... • Correlation of volume to level varies with geometry of tank and may be expressed in terms such as: » gal/inch, liters/meter, barrels/inch... Level 1 - Level

Level terminology Parameters

12

r

Volume • Vertical Cylindrical Tank » v = πr2l

h

l

h

• Horizontal Cylindrical » v = πr2atan[l½/(2r-l)½]+h(l-r)[l(2r-l)]½

• Sphere Tank » v = πl2(3r-l)/3

r

l

r l

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Level terminology Parameters

13

Volume • Horizontal Bullet Tank » v = πr2/3 * (3r-l) + 2r2(h-2r) *atan[l½/(2r-l)½] + (h-r)[l(2r - l)]½ h r l r h

• Vertical Bullet Tank l » v = πr2/3(3r-l) if l ≤ r » v = πr2/3(3r-l) if r < l < (h - r) » v = πr2(h-2r) + [π(l+2r-h)2]/3 * [3r-(l+2r-h)] if (h - r) ≤ l Level 1 - Level

Level terminology Parameters

14

Volume • Tanks with Dished Ends » no standard shape – use strapping tables to determine volume 10

9 7 5 3 1

Point

Level Volume (inches) (gallons)

1 2 3 4 5 6 7 8 9 10

0 5 10 15 20 25 30 35 40 100

0 10 32 68 115 173 230 313 394 957

Bulging

A look-up table that relates level to volume for several discrete points in a tank. Commonly used to eliminate Bulging Error.

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Level terminology Measurement Characteristics

15

...and the technologies may have to handle a number of application conditions. 0

-14.7

PSIG

Steam, Steam,vapors, vapors, dust dust

Abrasive Abrasive fluids fluids

Foam Foam

Density Changes

High High vacuum vacuum

Corrosive Corrosive processes processes

Viscous Viscousor or sticky stickyfluids fluids

Temperature Temperature extremes extremes

Agitation Agitation

Level 1 - Level

Level terminology Measurement Characteristics

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Bottom-Up vs. Top-Down Measurement Top-down Top-Down Measurement • Poses less potential for leakage • devices installed or removed without emptying tank ˆe.g., dipstick, radar gauge Bottom-Up Measurement • Typically contacts the process fluid ˆe.g., pressure transmitter, weigh scale

Bottom-up Level 1 - Level

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Level terminology Measurement Characteristics

17

Inferred vs. Direct Measurement • An Inferred measurement is derived from another measurement Ex: pressure transmitter HeadPressure = Level , Mass = Level Density Density Stability of variables is critical to get a good inferred measurement. If variables are not stable, compensation needs to be made. • A Direct measurement looks only at the desired variable Ex: floats, dipstick Level 1 - Level

Level terminology Measurement Characteristics

18

Continuous vs. Point Measurement

Continuous Measurement

Point measurement

• Constant detection of product height • Concerned with amount of product • May be used to control addition of other components to the vessel

• Has the level reached this point? • High or low level detection • Often used for alarm control • May start or stop pumps • May open or close valves

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Level terminology Measurement Characteristics

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Non-Contact vs. Non-Invasive vs. Non-Intrusive NonNon-Contact implies that the device does not touch the fluid, but it could be invasive

NonNon-invasive implies that the device does not pass the walls of the tank nor touch the process directly

Intrusive NonNon-intrusive implies that the device may come in contact with the fluid, but does not protrude into the fluid or interfere with fluid movement Level 1 - Level

Technology selection Level Measurement Technologies

20

Bubbler Dipstick Capacitance Tuning Fork

Float

Ultrasonic Radar Sight glass Nuclear Displacer

Gage Glass

Differential Pressure

Ultrasonic Gap Hydrostatic Weight Level 1 - Level

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Level

Technology selection Classification of Level Measurement Technologies Contacting N oncontacting Point

21

C ontinuous Liquids Solids

Bubblers Capacitance Conductivity Displacers Floats HT G Hydrostatic Laser M agnetostrictive Nucleonic Optical Phase Difference Radar Resistance T ape Rotation Suppression Servo T ape Level T hermal Ultrasonic Vibration Weighing Level 1 - Level

Technology selection Classification of Level Measurement Technologies Density Interface Level Bubblers Capacitance Displacers Floats HT G Hydrostatic Laser M agnetostrictive Nucleonic Phase Difference Radar Resistance T ape Servo T ape Level Ultrasonic Weighing

22

M ass

Note: Only continuous devices included

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Level

Technology selection Factors To Consider

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• Why is the level measurement needed? ˆWhat are you try to measure? ˆWhat are you trying to achieve? – – – – – –

Indication of fluid level Alarm set point to prevent spill over Transfer (Sale) of product Contol of Product Mix Leak Detection Interface detection

• What are the conditions within or on the vessel? ˆ Product turbulence ˆ Obstructions ˆ Mounting constraints ˆ Angle of repose for solids ˆ Temperature and pressure limits Level 1 - Level

Technology selection Factors To Consider

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• What are the environmental conditions? ˆ Ambient Temperature ˆ Humidity ˆ Vibration ˆ Electro Magnetic Interference(EMI) ˆ Transient protection

• What are the product characteristics? ˆ Corrosive ˆ Viscous ˆ Dusty, Foam ˆ Variable Density ˆ Variable Dielectric constant ˆ Tendency to Coat ˆ Interfaces, gradients, suspended solids ˆ Steam or other vapors Level 1 - Level

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Technology selection Factors To Consider

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Common Density/ Temperature Changes

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Technology selection Factors To Consider

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Typical Dielectric/ Temperature Changes

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Technology selection Factors To Consider

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• What are the instrument requirements? ˆ Performance requirements ˆ Location approvals ˆ Power requirements ˆ Output requirements ˆ Number, location, and size of taps ˆ Total costs

– Product – Installation – Maintenance

Level 1 - Level

Technology selection Performance Consideration

Environmental Factors

Device

Direct vs inferred Measurement capabilities Rangeability

28

Temp changes Vibration Noise

Process Density changes Conditions temperature changes static pressure agitation aeration foam dielectric changes Level 1 - Level

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Technology selection Working Capabilities Vary with Technologies 10000+

29

Nucleonic Capacitance

3626

Pressure, PSI

Pressure w/ seals

Pressure/HTG

1000

Displacer

Ultrasonic Point

Ultrasonic 73 atm -240

Radar -100 -40

32

195

320

600

400

800

900+

Temperature, oF Approximate values are shown. Pressure and temperature limits are shown independently of each other.

Level 1 - Level

Technologies Pressure Transmitters

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Open Vessel Level Measurement In open vessel a pressure transmitter mounted near the bottom of the tank will measure the pressure corresponding to the height of the fluid above it.

Phead



Phigh = Phead + Patm Plow = Patm



Patm

Phigh - Plow = Phead

Patm

What happen to Atmospheric pressure?

XMTR L

H

Cancelled Off Level 1 - Level

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Technologies Pressure Transmitters

31

Transmitter mounted above the tap in an open vessel What happens when the liquid level drop below the sensor ? 100% XMTR 0% L

h

g

H

0%

The sensor will not be able to sense any pressure change !! The 0% has to be at least at the same level as the transmitter sensor or below the tapping point.. Level 1 - Level

Technologies Pressure Transmitters

32

“Zero Suppression” is often applied to compress the range of the transmitter OR to cancel the effects of the liquid head in the pipe connecting the transmitter to a tank when the transmitter is mounted below the vessel connection. At min. level the High side

pressure is high than the low side pressure

4mA

Min. Level

Actual Zero Suppressed XMTR L

20mA

Max. Level Range

Max. Level Range

20mA

Actual Zero4mA Suppressed XMTR

H

L

Min. Level

H Level 1 - Level

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Technologies Pressure Transmitters

33

“Zero Elevation” is often applied to cancel the effects of the head caused by the seal fluid in the reference leg (low side) of a transmitter measuring level in a pressurized vessel.

XMTR

4mA Actual Zero Elevated

Range

Max. Level

20mA

Min. Level

At min. level the low side pressure is high than the high side pressure

L H

Level 1 - Level

Technologies Pressure Transmitters

34

Closed Tank Level Measurement (Dry Leg) Dry leg: no fluid in low side impulse piping, or leg If the gas above the fluid does not condense, the piping for the low side of the transmitter will remain empty.

 

Phigh = Ptop+Phead Plow = Ptop

Ullage or Vapor

Phead XMTR L

H

Phigh - Plow = Phead Level 1 - Level

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Technologies Pressure Transmitters

35

Closed Tank Level Measurement (Wet Leg) Wet leg pressure is additive to pressure on low side of the transmitter. If the gas above the liquid condenses, the piping for the low side of transmitter will slowly fill with liquid. To eliminate this potential error, the pipe is filled with a convenient reference liquid.

 +P 

Phigh =Phead+Ptop Plow=Pwet leg

Ptop= Ullage

Pwet

Phead

L H XMTR

top

Phigh - Plow = Phead - Pwet leg Level 1 - Level

Technologies Pressure Transmitters

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Limitations • Bottom-mount technology: potential leakage • Often requires 2 taps • Variable density creates errors • Temperatures beyond 600 F • High vacuum applications are tricky • Highly corrosive processes limit life • Abrasive processes can damage diaphragms • Liquids Only

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Technologies Pressure Transmitters

37

Bubbler System Consists of air supply, pressure regulator, flow meter, transmitter & extended tube. Can be used for very corrosive applications. Tank vented.

TXR Pin(flow=const)

Pressure to maintain flow = Phead Air is bubbled through the tube at a constant flow rate. The pressure required to maintain flow is determined by the vertical height of the liquid above the tube opening times the specific gravity.

H S.Gf

Phead = H * S.Gf

Level 1 - Level

Technologies Pressure Transmitters

38

Gauge Pressure Transmitter

Application of Bubbler system: • Allows dp to be a top down measurement • No process contact with transmitter • Open or low pressure • Control of Air supply is important for accuracy

Valve Air Supply

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Technologies Pressure Transmitters

39

Remote Seals Reliable, Simple, Easy to Use, Well Understood, Flexible Uses: Diaphragm Seals extend limitations due to process conditions such as: high temperatures corrosion viscous materials suspended solids plugging sanitary needs

Differential Pressure Transmitter

Level 1 - Level

Technologies Pressure Transmitters

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Typical Pressure Applications •CPI / HPI ˆBatch reactors ˆ digesters ˆfractionators ˆdistillation column bottoms and reflux drums ˆseparators ˆ surge drums ˆ reservoirs ˆ intermediate storage... •Power ˆdrum level ˆ dearators...

•Pulp & Paper ˆHeadbox ˆStock Tanks ˆChemical Storage tanks ˆEvaporators ˆLow concentration liquor tanks... •Food and Beverage ˆFermentors ˆstorage tanks ˆaging tanks ˆ brew kettles... And many more! Level 1 - Level

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Technologies Radar Gauge

41

Frequency Electromagnetic Wavelength, Meters Cycles/second

Spectrum

10 22 gamma rays 10 20 10 18 10 16 10 14

10 8 10 6

x-rays ultra violet visible light

Radio Detection And Ranging 10 -9 10 -7 10 -5

Radar, 3-30 GHz

10 -3

Microwave oven,

--------super high freq--------------ultra high freq-------------------TV broadcasting-----------------FM Radio-------------------low frequency------------

10 4 10

Radar is an Electromagnetic Wave

10 -11

10 12 10 10

10 -13

2

10 -1

2 - 10 GHz 10 1 10 3

Cellular, pager,

10

5

300-3000 MHz

10

7

Level 1 - Level

Technologies Radar Gauge

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Radar Techniques • Pulse » Measures range ( distance ) » Transmits a pulse and measure time until echo is received » Accuracy depends on ability to measure time – Radar signals travel at the speed of light. – Must measure in picoseconds ( x10-12 ) ! – Cost-effective electronics do not exist to do this accurately !

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Technologies Radar Gauge

43

Radar Techniques • FMCW: Frequency Modulated Continuous Wave » Does NOT calculate time-of-flight » Evaluates the phase difference between the transmitted and return signal » Plotting these phase differences against the transmitted signal yields a result proportional to distance

Level 1 - Level

Technologies Radar Gauge

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Advantages of Radar Gauge • Non Contact, Non Intrusive • Tolerates Wide Range of Process Conditions » Corrosive Processes » High Temperatures » Changes in Vapor Space » Variable Density » Variable Dielectric » Viscous or Sticky Products • Low Maintenance • No Special Licenses Required • Can measure long distances • Liquids, pastes, solids Level 1 - Level

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Technologies Radar Gauge

45

Radar Application Considerations • Sensors can be completely removed from process by use of a window made out of a nonmetallic material, such as Teflon, Ryton, Ceramic • Sensors can be removed from the process without opening the vessel Radar Limitations • Cost • May not work with processes with low dielectric constant • May not work in applications with large amounts of turbulence • Process connections tend to be large (>4” flanges) Level 1 - Level

Technologies Radar Gauge

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Possible Applications •Pulp & Paper »High Density Storage »Color tanks »Bleach tanks »Hydropulpers »Retention tanks »Black liquor tanks •Pharmaceutical »Batch reactor »Chemical storage •Power »Slurries

•Chemical »Polymers »Latex »High temp »LPG tanks »Butane sphere »Batch reactors »Two-phase sludge »Cyclohexane •Minerals »Steel Scale Holding Tanks

And More! Level 1 - Level

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Technologies Radar Gauge

47

Radar vs. Ultrasonic Gauge Similarities: Both technologies Top down, non contact Easy to install Good for abrasive materials, slurries Not affected by changing fluid properties: density, conductivity, dielectric

Differences: Radar Full vacuum to several hundred psi Wide temperature limits Can handle steam, fog, vapors Can handle some foams and agitation Can be used with windows

Ultrasonic Very slight vacuum to about 100 psi Narrow temp band (<200 F) Is greatly affected by changes in vapor space Signal is lost in foam and agitation Level 1 - Level

Technologies Radar Gauge

48

Radar vs. Ultrasonic Gauge Gas

Temp (oC)

Dry Air

Water vapor

0 100

RADAR million m/s 299.91 299.94

ULTRASOUND m/s 331.8 386

100

299.10

404.8

Carbon Dioxide 0 50

299.85 299.87

250.0 279.0

Ammonia

0

299.93

415.0

Acetone

0

297.64

223.0

Source: Instrument Engineer’s Handbook, Liptak Level 1 - Level

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Technologies Float Mechanism

49

Internal Still pipe to guide the float

External Still pipe to guide the float

Indicator

Float

Float Isolating Valve

Tank

Drain Valves

Indicator

Float-operated gauge level-indicator, indicates liquid level in cone or flat roof unpressurised tanks. Recommended for use on tanks storing water, fuel, oil, chemicals or other liquid products where operations do not require extreme accuracy. Level 1 - Level

Other technologies Capacitance Probe

50

• A capacitance instrument measures amount of capacitance between two plates of a capacitor. • The capacitance of a capacitor increases if a dielectric is placed between the plates • Circuit applies high frequency signal to probe C = KEoAd where

k

K = dielectric constant of material Eo = permitivity of vacuum A = Area of plates (probe) C = capacitance (pF) d = distance between plates d

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Other technologies Capacitance Probe

d

51

How Capacitance varies with process fluid?

Nonconductive Coating

Level is proportional to dielectric change

Level is proportional to plate area change

Nonconductive Fluid

Conductive Fluid

• Process fluid is the dielectric barrier • Tank Wall forms second plate • The variation of dielectric is the measurement

• Process fluid is the second plate • Insulation on probe is dielectric • The variation of the plate size is the measurement

Level 1 - Level

Other technologies Capacitance Probe

52

• Limitation – Change in Dielectric creates error – Coating on probe by product creates errors – With non metallic tanks or tanks without vertical walls, addition of reference probe is required – Calibration can be difficult especially since one cannot “bench calibrate” – Changing vapor space can affect output

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Other technologies Capacitance Probe

53

Potential Applications •Pulp & Paper ˆSewage level ˆLiquor tanks ˆBulk solids •Chemical ˆInterface: fatty acid/water, oil/water ˆCarbon black ˆSeparators •Food & Beverage ˆStorage silos

•Oil & Gas ˆWater bottom ˆWater cut

Level 1 - Level

Other technologies Displacers Based on Buoyance Force The displacer is buoyed up by a force proportional to the weight of the liquid it displaces

54

0

pounds

0

pounds

Vertical movement of the displacer is converted to angular movement by mechanical linkages

Angular movement is then converted to electrical or pneumatic output.

Buoyant force increases as level rise Level 1 - Level

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Other technologies Displacers

55

Good for short span measurement

Liquid Level Measurement

Interface Measurement

Density Measurement

Level 1 - Level

Other technologies Displacers

56

Benefits: • Simple, Reliable. • Good for Interface measurements. • Good for Density measurements. • Unaffected by Agitation. • Tolerates High Temperatures and pressures. • Point or Continuous . Limitations: – Does not tolerate viscous, dirty, or sticky fluids – Variable density causes errors in level measurement – Typically used for smaller spans (cost effective) – Must be installed carefully – Intrusive & Contact Level 1 - Level

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Other technologies Displacers

57

• Typical Applications: ˆOil and Water interface ˆOil and Gas Separators ˆStripper Reflux Drum Level ˆDehydration Units ˆEffluent Separators ˆAbsorption Towers ˆCondensate Discharge Accumulators ˆDensity and Interface Measurements

Level 1 - Level

Other technologies Servo Gauging Uses a combination of a displacer and a spring balance The servo motor strives to obtain an equilibrium between the displacer and the balance. Any change in level will cause a change in equilibrium. ˆAdvantages: – Very precise (1 mm accuracy) – Can measure level, interface – relatively low cost ˆLimitations: – Intrusive – Mechanical linkages

58

Storage Drum

Cable

Balance Detector

Servo Motor

Displacer

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Other technologies Nucleonic Gauging

59

Single Point System Gamma rays are emitted from the source. The presence or absence of the gamma rays is measured by the detector. Gamma

Nucleonic level switches use Source radioisotope sources sized to provide measurable radiation at the detector when no product material is present between source and detector.

Detector

Level 1 - Level

Other technologies Nucleonic Gauging

60

Continuous System Nucleonic level transmitters use the same radioisotope sources, but respond to the total absorption of gamma rays as they pass from the source to detector.

Source

The amount of radiation reaching the detector is inversely proportional to the amount of material in the vessel. Detector

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Other technologies Nucleonic Gauging Advantages: – Unaffected by: • • • • • • •

High temperatures High Pressures Corrosive Materials Abrasive Materials Viscous Materials Agitation Clogging/Plugging

61

Limitations: – Large density changes can create errors – Layer of coating on vessel walls create errors – Licensing Required – Leak Checks required – Cost

– Point and Continuous – Liquids and Solids – Interface (based on H2 density) Level 1 - Level

Other technologies Nucleonic Gauging Typical Applications •Chemical ˆDistillation Tower ˆBatch Reactor ˆStorage Tanks ˆResin Bed level ˆHydrocracker reactor •Pulp & Paper ˆDigester Level ˆWood Chip Bins ˆBleach Tower ˆConsistency ˆEffluent Waste ˆSlurries ˆLiquor concentrates

62

•Refining ˆFractionator Tower ˆSurge Tanks ˆCoke Drum Interface ˆDesalter •Food and Beverage ˆHopper Level ˆBlending Vats •Mining ˆCrusher Level ˆStorage silos ˆSlurries •Utilities ˆSO2 / Lime scrubber ˆFly ash Slurries Level 1 - Level

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Other technologies Laser

63

• Function: Uses infrared light to send a focused beam towards surface. Time of travel and reflection is measured. • Narrow, focused beam: good for applications with space restrictions. • Non contacting: uses a window • Accuracy: +/- 1 cm • Works best in cloudy, shiny liquids or solids • May pass through surfaces of clear, still fluids • Cannot tolerate dust, fog, steam or vapors • High cost • Alignment is critical

glass window

laser device

Level 1 - Level

Other technologies Ultrasonic Gauging

64

A sound pulse(9 to 160 kHz) is transmitted and reflects off the surface back to the transceiver. The true reflected echo pulse is extracted and the time interval between transmission and reception is evaluated electronically.

• Advantages:

Sound Waves

ˆNon Contact ˆNo element contamination ˆCan be used for liquids and solids ˆTolerates Many Process Conditions: 9 9 9 9 9

Varying Density Corrosive Processes Viscous Product Varying Dielectric Sludge Buildup

The higher the level the faster echo reflected Level 1 - Level

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Other technologies Ultrasonic Gauging

65

Application Considerations • Conditions of the vapor space impact speed of signal travel and thus, the measurement • Changes could be due to: – – – –

Sound Waves

temperature dust vapor composition stratification of the vapor

• Some units have temperature compensation • Gas blankets can be used to provide uniform vapor space condition Level 1 - Level

Other technologies Ultrasonic Gauging

66

Application Considerations • Process surface conditions can affect signal return . Surface must have ability to reflect signal. • Heavy agitation and foam may cause signal to be absorbed • Vortex in fluid can misdirect signal • In open, outdoor installations, wind can blow signal off coarse • Stilling wells can be used to isolate the surface and contain signal.

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Other technologies Ultrasonic Gauging

67

Limitations – not suitable for vacuum service – Cannot tolerate high temperatures (>200 F) – Foam interferes with signal – Agitation may distort signal – Internal obstacles can create false echoes – Nearby equipment could generate frequencies that will cause errors – Vapor pressure limited to 50 psi

Level 1 - Level

Other technologies Ultrasonic Gauging Typical Applications •Chemical ˆDistillation chamber ˆCorrosives ˆSlurries ˆLatex PVC ˆWaxes •Food and Beverage ˆDearating vessel ˆalcohol fermenter ˆbaking batter ˆchocolate ˆdairy products ˆgrain storage •Cryogenic systems (point level)

68

•Waste water ˆClarifier ˆSettling tanks ˆReservoirs ˆFlood control ˆSludge levels •Pulp & Paper ˆBlack liquor w/ solids •Pharmaceutical ˆEmulsions ˆLotions •Marine ˆFuel or ballast water indication ˆBilge alarm Level 1 - Level

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Exercise

69

1. Which has the best accuracy on 6 meter High Water tank? A. Hollow or glass fill float with mechanical gauge (1 inch) B. “Servo” Gauge (1 mm) C. Pressure Transmitter ±0.1% of F.S [ ] 2. An inground reservoir is 5 meters deep. Which of the following method(s) will be suitable to measure and transmit the level without having to dig a hole to reach the bottom of the reservoir or the scour main. (Answer Yes [Y] or No [N]) A. B. C. D. E. F. G.

Differential Pressure Servo Level Gauge Capacitive Probe Nucleonic Gauging Ultrasonic Gauging Radar Gauging Bubbler System

[ [ [ [ [ [ [

] ] ] ] ] ] ] Level 1 - Level

Exercise

70

3. For HTG, why is a 2nd Pressure Transmitter added to tank in the middle ?

4. Which one of the following tank gauging system is based on Mass? (A) Radar (B) Nucleonic (C) Servo Balance (D) HTG [ ]

5. Which of the following statement about Radar Gauge is NOT True ? (A) Top-down mounting (B) Can handle agitated & sticky process fluid (C) Can be used on a tank with non-metallic internal surface. (D) Can handle process with deep vacuum [ ]

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Exercise

71

6.

5’

Assuming SG is = 1.1 What is the volume?____________ft3 What is the density of this fluid?___________#/ft3

10’

What is the mass?__________pounds What is the pressure level reading? ________in H2O

water = 62.4 # / ft3

Level 1 - Level

Exercise

72

7.

5’

Now, suppose the SG changes to 1.05 and the level does not change What is the volume?____________ft3 What is the density of this fluid?___________#/ft3

10’ What is the mass?__________pounds What is the pressure level reading? _______in H2O

water = 62.4 # / ft3

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Exercise

Level

73

8. Pmeasured = 150 inH2O s.g. = 1.5

Pin(flow=const)

What is the fluid level in the tank?

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