laser gas detection increases safety and …€¦ · laser gas detection increases safety and...

Laser Gas Detection increases Safety and Environmental Performance in Fertilizer Plants

• Hamish Adam

• President & CEO

• Boreal Laser Inc.

Organization logo to appear here

Outline

• Introduction to Laser Gas Detection

– Basic concepts

– Portable systems

– Multiple path fixed installations

– Point sensor

• Laser benefits for leak detection and tracking

• Fertiliser industry examples – Ammonia and Urea production

– HF monitoring in phosphate plants

– Monitoring NH3 from fertiliser application

• Conclusions


Boreal Laser overview

• Based in Edmonton, Alberta, Canada

• Manufacturer of laser based gas detectors since 1996 – Products use Single-line absorption spectroscopy in NIR with Wavelength

Modulation Spectroscopy / Direct Absorption

• 2000 – transitioned from research to commercial sales

• 2013 – 5 distinct “GasFinder” product lines – world-leading supplier of open-path laser gas detection systems for safety and

environmental applications.

– Installations in over 40 countries worldwide

– >600 GasFinder systems shipped (>1200 measurement paths)

– Reputation based on product reliability and technical support

– Commitment to providing factory-trained local sales and service


How Portable GasFinder2 measures trace gases in the air


• GasFinder emits a laser beam that is absorbed only by Trace Gas of interest (eg NH3)

• The Reflector Array returns the laser beam to the GasFinder

• Electronics and software in the GasFinder analyze the resulting photodiode signal using Wavelength Modulation Spectroscopy.

• The result is the average concentration of the Trace Gas in the measurement path

• The measurement path can be up to 500m long (1000m for select gases)

GasFinder2

Ambient air being measured by the GasFinder

Up to 1000m Retro-reflector

Laser-Based Gas Detection Organization logo to

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Major benefits of single-line laser absorption spectroscopy are:

• High resolution, excellent selectivity

• Minimum interference from other gases (especially H2O, CO2)

• No consumables, minimum maintenance

• Diode lasers were developed for telecom industry and have >15 year lifetime

Typical values:

NH3 line width – 0.02 nm

Laser line width – 0.0002 nm

Laser tuning range – 0.2 nm

Portable GasFinder2 – main components Organization logo to

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Reference cell contains stable sample of target gas, known concentration

Laser beam redirected through reference cell for 0.25 seconds every 10 seconds

No need for in-path validations with bottled gases and calibration tubes

All GasFinders calibrated against NIST traceable permeation tubes.

Signal Processing

and Display

Laser Diode

Aiming Laser

Control Electronics

Detector

Detector

Calibration Reference Cell

Remote Retro-Reflector

Sighting Scope

Computer

The aiming laser, used to aid alignment, emits a highly visible red light

Gas-measuring laser light emitted by the laser diode is invisible — in the near infrared (about 1500 nm)

GasFinderMC – multi path system for fixed installation gas detection


Signal Processing

and Display

Laser Diode

Detector

Calibration Reference Cell

Aiming Scope

Computer

Mu

ltip

lexe

r

Control Electronics

Remote Head Retro- Reflector

Duct Sensor

Key

pa

d

GasFinderPT – laser gas point detector Organization logo to

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• Available for HF – NH3 soon

• 20 cm open path essentially a “point” measurement

• 3 analog, 3 digital outputs and local display

• Operates from -40 C to +50 C

• Developed in conjunction with ExxonMobil

• Provides precise ppm reading for personnel protection and accurate plume modeling

Laser gas monitoring benefits

Laser Open Path and Point Detectors

• Gas-specific: No false alarms

• Area coverage with open path: More reliable leak detection

• One second response: More time to react

• Optical absorption technique: No poisoning, no “memory” effects

• Laser light not absorbed by water vapor: Enables long paths — 500m or greater

• Reliable unattended performance in all climate conditions

• No consumables, no moving parts: Minimal maintenance, reduction in O&M need


Traditional Point Sensors

• Cross sensitive to other gases: False alarms possible

• Relatively slow to respond: Typical T50 rating of 25 seconds

• Poisoned by exposure to NH3: exhibits memory effects

• Some sensors only rated to -10 C: don’t work outside in winter in many places

• Maintenance Intensive: calibration, test gas, replacement heads required.

• Large Operating and Maintenance (O&M) cost: e.g. array of 30 point sensors in cool, damp northern latitude estimated $100,000 in maintenance costs per annum PLUS 1 – 2 man hours per sensor per month

Scanning portable configuration for emissions flux monitoring


• Laser detector on scanner measures Path Integrated Concentration (PIC) over multiple paths in succession

• Combine PIC data with meteorological data

• Wind data most important. 3D ultrasonic best

• Analyze data with available algorithms to:

• Create concentration profiles which locate hotspots.

• Provide emissions flux estimates

• Calculate emission source strength

Source Wind

Direction

Ground measured retro-reflectors

IR beam executing a single "monitoring event"

(5 events make up a complete "plume traverse")

Retro-reflectors mounted

above the ground

Laser detector mounted on scanner 360˚ pan movement, 120˚ tilt movement Wireless control

Leak detection and plume mapping with SAFER Real-Time®


Combine BOREAL open path

laser detectors with SAFER

Real-Time® to simplify early

detection, monitoring and

tracking of an ammonia (NH3)

release.

BOREAL sensors integrate

with SAFER’s patented “Open

Path ABC” (Advanced Back

Calculation) release rate

estimation algorithm to alert

plant operators of any loss of

containment and help

quantify, predict and plot the

downwind impact at the

fence-line and beyond.

Process unit leak detection – monthly log Organization logo to

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Continuous monitoring on 4 independent paths surrounding a process unit over a 1-month period

Note daily spikes resulting from process sampling

Fertiliser industry examples

• Current experience is with NH3 and HF monitoring

Reactive gases, difficult to monitor continuously with traditional methods.

Laser sensitivity and range well suited to accurate and quick detection at typical alarm levels:

HF: 3 – 10 ppm NH3: 30 – 100 ppm.

• Ammonia and Urea Production - most experience

Typical NH3 monitoring installations are 2- to 6-path

NH3 compressor leak monitoring

Perimeter monitoring at NH3 storage facilities

NH3 railcar loading/unloading

NH3 Distribution terminals

Urea prilling tower emissions

• HF monitoring in phosphate plants – a few installations

• Monitoring fugitive NH3 emissions from fertiliser application in agriculture


Ammonia and Urea Production – Risks & Incidents

• 550 NH3 plants worldwide 200 million tonnes of NH3 every year.

• 83% of NH3 production used in fertilizers

• greatest use in urea manufacture (500 plants worldwide).

• Large amounts of NH3 produced, transported and consumed worldwide

• Considerable potential for accidents

• NH3 is a stable and non-flammable gas but is toxic and dangerous to humans.

• Exposure to high concentrations of gaseous NH3 can result in lung damage and death.


Odour threshold OSHA 15-minute OSHA 8-hour NIOSH IDLH

5 ppm 35 ppm 25 ppm 300 ppm

IDLH (Immediately Dangerous to Life and Health) is the level to which a healthy

worker can be exposed for 30 minutes without suffering irreversible health effects.

Potential sources of NH3 leaks in NH3 and Urea production

• High pressure NH3 pumps and compressors

• Refrigeration compressors which recirculates NH3 coolant

Ambient levels are typically between 18 – 25 ppm because of bleed past seals.

• NH3 storage facilities and Trans-shipment Terminals

loading and unloading operations provide multiple opportunities for

accidental releases of NH3.

• Urea plants have several continuous and discontinuous NH3 emission

sources.

High pressure ammonia pump at the base of the urea tower

Piping, valves and safety rupture disks

Prilling towers


NH3 compressor room monitoring Organization logo to

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Path on left is 20 cm (blue trace) Path on right is 25m (red trace)

Note: NH3 spike to 98 ppm during filter change

Perimeter NH3 leak detection Organization logo to

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Perimeter detection at NH3 storage area (L) and plant boundary (R)

NH3 storage tank monitoring Organization logo to

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Temporary monitoring with GasFinder2 Permanent monitoring with GasFinderMC

Fence-line NH3 monitoring Organization logo to

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Path averaged NH3 concentrations on a 320m path along a boundary near a cold ammonia storage tank and flare

Urea tower NH3 emissions monitoring Organization logo to

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NH3 monitoring at top of prilling tower with 2m open path measurement. Note persistent mist – and high NH3 levels!

Retro-reflector

Open Path head

Ureaknowhow.com incident database

• Describes more than thirty incidents in urea plants and ammonia pipelines.

• 80% are related to failures in high pressure equipment and high pressure piping systems.

• These incidents led to at least 40 fatalities and 80 additional injuries.

• Early detection of ammonia leaks is vital to

– give operators precious time to reach personal protection equipment

– limit the area where ammonia vapours can cause problems and

– shut off combustion sources.

• Improved ammonia leak detection will lead to a safer industry with fewer casualties and injuries.


HF fugitive emissions from a phosphogypsum pile


0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

08:0

8:30

08:5

1:36

09:3

3:52

10:1

4:04

10:5

4:10

11:3

4:18

12:1

4:24

12:5

4:32

13:3

4:42

14:1

4:56

14:5

5:38

17:0

4:12

17:4

4:36

18:2

5:00

19:0

5:30

19:4

6:10

20:2

6:44

21:0

7:24

21:4

8:10

22:2

8:50

23:0

9:32

23:5

0:22

00:3

1:14

01:1

2:06

01:5

3:00

02:3

3:58

03:1

4:58

03:5

5:58

04:3

6:58

05:1

8:02

05:5

9:06

06:4

0:06

Time

ug F

/m3

FTIR HF data FTIR SiF4 data Laser HF data

NH3 flux monitoring from farms Organization logo to

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Conclusions

• Laser gas detectors have distinct benefits for leak detection and environmental monitoring

Lack of cross interferences – hence no false alarms

Fast response

Wide measurement range

Reliable operation in all climate conditions

Not poisoned or taken off-line when NH3 detected during maintenance

No moving parts and no consumables reduces cost of ownership

• Several applications have been successfully demonstrated in the fertilizer industry

Especially for reactive gases such as NH3 and HF

Early detection, monitoring and tracking of NH3 releases is simplified by combining laser gas detection with release rate algorithms such as SAFER Real-Time®


laser gas detection increases safety and …€¦ · laser gas detection increases safety and...

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