ISA QATAR : 90th Seminar - AIMS QATAR - AIMS.pdf · Points considerations in Process Analyzers 33. No heating/ Jacketing ... • Aims studied the case and proposed AMETEK 5100-HD

ANALYTICAL INSTRUMENTATION &

MAINTENANCE SYSTEMS (AIMS)

“UTILIZATION OF LASERS IN THE FIELD OF GAS ANALYZERS”

Presenter:

ZAHEER JUDDY

ISA QATAR : 90th Seminar

Electromagnetic Spectrum

Analytical Instrumentation & Maintenance Systems(AIMS)

5510 10 10 10 10 10 10 10

9 7 5 3 1 -1 -3 -

Wavenumbers

x-rays

ultraviolet

Vis

NIR

mid -IR

FIR

microwave

radio waves

nuclear electronic vibrational transitionsrotational

10 10 10 10 10 10 10 109 7 5 3 1 -1 -3 -

Wavenumbers

x-rays

ultraviolet

Vis

NIR

mid -IR

FIR

microwave

radio waves

Wavelength in Nanometers

nuclear electronic vibrational transitionsrotational

180 1000 25000


Electromagnetic Spectrum

Traditional techniques/approach in process Gas Measurements

• Non-Dispersive & Dispersive Infrared

• Non-Dispersive & Dispersive Ultraviolet

• Contact type measurement


• Tunable Diode Laser Absorption Spectroscopy (TDLAS)

Next Generations


Infrared (IR) Technology

About & Challenges• Very Old & First technology• Suitable for only measurement of Hetro-atomic molecules• Moisture interference with IR• Not suitable for interfering background Gases and components• Complex Sampling design with removal of moisture MUST….

• Increased number of consumables and spares

NDIR Photometry:• AGAIN!! A complexity of optical design with lot of

optics components.


Components – IR analyzer:

• Degradation of NDIR source.

• Contamination of filters.

• Wide band width (CO2/CO) together difficulties

NDIR source

Filters

background interference


Ultraviolet (UV) Technology

UV Optics Assembly

Few Challenges:• Shorter lamp life• Wide emission line widths &

wide Spectral range.

• Contamination of filters.

• Moving parts• Replacing the filter wheel

motors.


Good for sulfur speciesH2S, SO2, COS, CS2, etc..

Filter Location Table (COS / CS2 Measurement)

Filter Position 1 2 3 4 5 6

Wavelength 258 228 404 232 280 326

Primary

MeasurementSv H2S NDr COS SO2 CS2

Lamp Mn/Ni Cd Mn/Ni Mn/Ni Mn/Ni Cd

Traditional Contact type Moisture & Oxygen Measurement

Moisture Measurement

1. Aluminum Oxides– Response Time in minutes/hours

– Sensor Probe Chocking

– Always affected by Glycol, H2S/HCL, mercury and others

– Difficulties in calibration

2. QCM (Quartz Crystal Microbalance)– Faster response & good for low ppm

measurement

– Sensor killing by background corrosive gases

Oxygen measurement

Zirconium Oxide (ZrO2)

– Selective for flue gases and clean applications

– Affected by dust, background mist and hydrocarbon gases

Think Out Of The Box????

The only tool

when you

have in your

hand is

HAMMER,

every thing

around looks

like NAIL .

AMETEK 5100HD PROCESS GAS ANALYZER


AMETEK Model 5100HD Overview

• The AMETEK 5100 series TDLAS gas analyzer is an extractive system & NON Contact type measurement

• All these species can be measured in variety of background gases

• There are two versions available. The Model 5100 is single laser, single analyte configuration.

• Model 5100HD is dual laser, single/multiple analyte single/dual cell configuration.

• Model 5100HD has dual stream capability.

• The unit is comprised of fully enclosed optics, electronics, sample handling and built-in verification.

• The unit is certified for worldwide hazardous area locations.

• comes with built-in verification and laser line lock as standard.


AMETEK Model 5100 Overview

Gases Measured• Moisture

• Hydrogen Sulfide

• Carbon Dioxide

• Carbon Monoxide

• Oxygen

• Methane

• Ammonia

• Hydrochloric Acid

• Acetylene

……many more coming


Industries Served• Natural Gas Pipeline

• Natural Gas Processing

• Refinery

• Chemical

• Petrochemical

• Hi Purity Gas

Many more……..

Why Tunable Diode Laser Spectroscopy?

• Non-contact measurement technique– No sensor aging calibration concerns

• No consumables– Advantage for applications with high levels of water vapor

– Lasers last many years before replacement is needed

– Low cost of ownership

• No interferences– Extremely narrow emission line widths reduce interferences from

other species


Electromagnetic Spectrum:

Wavelength modulation spectroscopy…

For First harmonic (1f ) detection, the detector signal is

demodulated using a reference signal with a frequency

equal to that (of the modulation frequency ) used to drive

the laser..

For Second harmonic (2f )detection, the detector signal is

demodulated using a reference signal twice that used to

drive the laser…..

http://en.wikipedia.org/wiki/Image:Scissoring.gif

http://en.wikipedia.org/wiki/Image:Rocking.gif

18

Vibrational Spectroscopy & Lasers• The absorption of infrared radiation results in unique

molecular vibrations

• In the gas-phase samples the individual transitions between discrete vibrational states are observed when measuring with high resolution

• Lasers have extremely narrow emission lines; hence, they are an excellent tool to probe the unique absorptions of gas phase molecules

O O O

H H H H H H

1

2

3

Normal Vibration Modes for Water


Modulation and Absorption ResponsesLaser Current

Detector Response

Water Absorption Modulated Laser Signal0 0.05 0.1 0.15 0.2 0.25

65

70

75

80

85

90

95

Time (seconds)

Cu

rre

nt

(mA

)

759.950

0.2

0.4

0.6

0.8

1

Wavelength

(nm)

Tra

nsm

issio

n

0 0.05 0.1 0.15 0.2 0.250

0.2

0.4

0.6

0.8

1

Time (seconds)

Respons

e


Analyte, typical absorption line width 0.05 nm

Laser scan range, typically 0.2 - 0.3 nm,

Laser spectral line width is ca. 0.0001 nm

Conventional optical filter bandwidth > 5 nm


5100 – Block & flow Diagram

Laser

Diode

ELectronics

Unit

TemperatureControl

Current

Control

MirrorGRIN Lens

Photodiode

GRIN Lens

Photodiode

Beam Splitter

Sample cell

Reference CellLaser

Diode

ELectronics

Unit

TemperatureControl

Current

Control

MirrorGRIN Lens

Photodiode

GRIN Lens

Photodiode

Beam Splitter

Sample cell

Reference Cell


Comparison of Water and Natural Gas

Water vapor spectrum

offset for clarity

1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 18600

0.2

0.4

0.6

0.8

1

Wavelength (nm)

Rela

tive A

bsorb

ance

1.854 um, 5394 cm-1Water Vapor

Natural Gas


Key feature of 5100 : Line-Lock• By adjusting the TEC temperature, the analyzer will tune the

laser to emit a specific frequency that would be absorbed by the analytes.

• check the peak (“line”) in the spectrum.

• The peak (“line”) is locked if its index is at a certain position in the spectrum, varying by a “line-lock” window.

Line Locking under Laser Temperature

of 27.55°C. Reference and Sample

Spectra

Spectral Index

0 50 100 150 200

2F

Sig

na

l

-0.01

0.00

0.01

0.02

0.03

27.4°C

26.8°C

25.5°C

25.55°C

25.54°C

Spectral Index

0 50 100 150 200 250

2F

Sig

na

l

-0.08

-0.04

0.00

0.04

0.08

0.12


Advantages of LASER:


• Precise measurement

Advantages of LASER:


• Precise measurement

DFB Tunable Laser Diode –The Heart of it All

• Very Accurate!! – Can be tuned to measure to the accuracy level.


Laser/Fiber Panel – 5100

Reference Cell – TDLAS

Verifying the Reference cell function:


Sample cell

Select Wisely:

Don’t Load all your application on

LASERS, you need to be careful on

the following.

• Always provide complete stream composition.

• Moisture and H2S in nitrogen is

dif ferent than moisture

and H2S in methane.

• Proper sampling system


COMMON ISSUES WITH SAMPLING SYSTEM

1. Sample Line Issues – Longer distance???

– As near as tapping point possible (less than 10 meters)

2. Probe Installation Issues

3. Big SHELTER/HVAC Issues – Maintenance issues

4. Location of Tapping Points – difficult to install and maintenance

5. SS 316 Electro‐Polished Tubes

6. Range issues for Analyzers

7. High H2S Exposure


Points considerations in Process Analyzers

33

No heating/ Jacketing

Proper Probe Heating with

Jacketing

Probe Installation Issues

Probe selection for high pressure process line Analyzers

Difficult location for Probe installation

Probe Installation Location

Heated Sample line selection & Installation

Proper bending & Installation of sample line

by AIMS

Shortest length between tapping point and analyzer less than 10

meters

Poor Installation – sample line


Sample installation Best Practices


Correct type of Heated Sample line selection

• Teflon: Inert but temperature limitations (dewpointtemperature), permeation

• Stainless Steel: welded, seamless but cleanliness and adsorption problems with some applications

• ElectroPolished: improved surface finish for improved absorption resistance

• ElectroPolished/Coated: for a product that is inert as Teflon but strong as steel

Weatherproof Jacket

“Insulation

Steam Traced

Process Lines

Steam Supply & Condensate Return

Electric Traced

CEMS Designs

Buffered High Temp Bundle


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Case Study 1 : ZADCO


• Analyzer application : ZADCO off-shore plant• Service : Glycol Dehydration Unit• Issue : Glycol & Liquide Carryover • Played with all the traditional techniques and was

failing. • Aims studied the case and proposed AMETEK 5100-HD

for the application. It has now been 5 years they are running smoothly.

Data Sheet

Case Study 2 : GASCO


• Analyzer application : Acid Gas Flare

• Measurement O2 in ppm : Range 0-1000ppm.

• H2S in the stream is 20%

• Analyzer is in ESD loop

Data Sheet For Case 2


Case Study 3: QP


• Service : Recycle Gas compressor suction

• Application : Moisture measurement.

• Process stream contains 15 ppm Chlorine (HCL).

• Existing : Al2O3

Data Sheet For Case 3


Case Study 4 : PDO OMAN


• Analyzer application : Acid Gas Flare

• Measurement O2 : 0-2%

• H2S in the stream

• Analyzer is in ESD loop

Installation in PDO, OMAN


Documents

ISA QATAR : 90th Seminar - AIMS QATAR - AIMS.pdf · Points considerations in Process Analyzers 33. No heating/ Jacketing ... • Aims studied the case and proposed AMETEK 5100-HD