SpectraSensors TDL Analyzer Overview-Process by huanghengdong


									SpectraSensors, Inc.
Tunable Diode Laser
Analyzer Overview
       Tunable Diode Laser (TDL)
         Spectroscopy History

• TDL was developed and refined by
  NASA at Caltech’s Jet Propulsion
  Laboratory over a 20 year period
• Original systems were developed
  and flown on aircraft and weather
  balloons used for atmospheric
• Achieved space flight qualification
  and launched on the 1999 Mars
  Polar Lander Spacecraft
• Today the technology is considered
  mature and reliable

Product Overview         2
June 8, 2006
               SpectraSensors, Inc.

• SpectraSensors established in
     – Acquired patent rights to
       commercialize the technology of the
       tunable diode laser
     – Based in San Dimas, California
• First application was ppm levels of            SpectraSensors’ Facility
                                                     San Dimas, CA
  moisture in natural gas streams
     – First unit was sold to El Paso Products
     – Over 1000 units sold since then
• Now offering other process
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June 8, 2006
   But What Are TDL Analyzers?

• Nothing more than fancy Infrared Analyzers* that
  folks are already familiar with
• But rather than using a lamp to produce lR light,
  TDL analyzers use a “focused” and “tunable” laser
• TDL technology is being driven by the fiber-optic
  telecom industry
• Goal is to retain the simplicity of IR analyzers yet
  avoid some of the measurement issues
  associated with IR analyzers
    * Note that TDL analyzers are available in IR and UV
      ranges depending on laser selected
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June 8, 2006
                   Optical Absorption

• Absorption of light is
  measured in order to
  determine the concentration
  in the gas sample.
• Light lost is directly and
  principally proportionate to
  absorbance of that light

           ρ = -ln(T) / k(ν) * L

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June 8, 2006
          Measurement Mechanics Of
            Optical Spectroscopy

 Concentration =   (How much light is absorbed (energy) thru the sample cell)
                   (Absorption Coefficient for a species) x (its path length)

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June 8, 2006
   On-Line TDL Analyzers Similar To
       Current NDIR Offerings

• Cross Stack design
     – Used to measure components in a combustion process;
       e.g., stack gases
• Open Air design
     – Used to measure components in ambient air monitoring;
       eg, toxic and flammable gases
• Portable design
     – Used to measure components in air or processes; e.g.,
       moisture in natural gas
• Extractive design
     – Used to measure components in chemical processes;
       e.g., gas purity applications

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June 8, 2006
         Optics Of A TDL Analyzer

     Laser and Detector Head

                    Sample Outlet

Sample Inlet

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June 8, 2006
               Tunable Diode Laser

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June 8, 2006
        Reading The Fine Print Of
          Spectral Signatures

                                     Laser Line


                            1 cm-1

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June 8, 2006
        Tunable Diode Laser Scan

                                                         Water vapour
              3.0                                        absorption peak
                        Laser Light Spectrum
                        Water Absorption Spectrum



              1370900           WAVELENGTH (picometer)   1371000

Tunable range 3 nanometers
Scanning 4 times per second
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June 8, 2006
                                              Ratio Of Signal At Peak And
Detector Response (arbitrary units)



                                         0                                                                                        CH4


                                                                                    Scan Range
                                              0   50   100   150     200      250       300         350         400         450         500

                                                                   Laser Current (wavelength)

          By ratioing the measurement against the baseline, errors caused by changes
              in signal strength, cell contamination, dirty mirror, etc are eliminated

                    Product Overview                                          12
                    June 8, 2006
        Analytical Benefits Of TDL

• Reduced measurement errors due to fewer
  interfering components
• Reduced effects of contamination due to oils and
  other compounds in the stream
• Low measurement ranges with long path samples
  cells (Herriott cells)
• Choice of IR laser sources
• Very fast response times

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June 8, 2006
                     Extremely Fast Speed of

         10000                                                        95% Response in <10 sec




                 0   5   10   15   20   25   30   35   40   45   50   55   60   65   70   75   80   85

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June 8, 2006
  Faster Recovery From Process

                           TDL Analyzer

                                                   Other Moisture Sensor
    Concentration of H2O

                                    Time (Hours)
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June 8, 2006
        Limitations Of TDL-based

• Still subject to interferences from very
  complex samples
• Typically limited to low pressure vapor
• Difficulty measuring compounds heavier
  than C3 in size
• Selection of IR lasers still limited to certain
  spectral ranges (but selection is

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June 8, 2006
        SpectraSensors Analyzers

• Compact field-mountable design
     – Div. II and Div I installations
     – NEMA 4 Packaging
• Flexible analytical hardware
     – Choice of IR or UV lasers
     – Single and dual channel
     – Multi-pass cells available
• Extremely low cost of ownership
     – No routine maintenance
     – No routine calibration needed
• Fast measurement response                   SS-2000
     – Most applications are done in 1

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June 8, 2006
        SpectraSensors Analyzers


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June 8, 2006
          Hardware Specifications

• Safety
     – Div II C,D standard (Optional Div I package available)
     – Gas pressure not to exceed 20 psia in sample cell
• Mounting Environment
     – Ambient Temperature: -20 to 50°C (0 to 122°F)
• Power
     – Choice of 120/220 VAC, 12 Volt DC, 24 Volt DC
• Signals (separate outputs for each channel)
     – 4-20 mA current loop (isolated, current source)
     – Serial data output (RS-232)
     – Digital Outputs (general purpose)

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June 8, 2006
            Extremely Low Cost Of
  • No routine maintenance needed
       – No moving parts or user adjusted
       – No contamination of measurement
         device due to oils other contaminants
       – No consumables                          Laser Head

  • No routine calibration needed                         Pressure Sensor
       – Self compensates for drift, loss of                                        Gas In

         signal, pressure and temperature
                                                               Temperature Sensor

       – Does this four times a second!              Gas Out
  • If cleaning of mirrors is needed,                                Sample Cell

    typically takes less than 30 minutes
       – Simply unbolt window section and
         wipe with optical quality cleaner
       – No permanent damage to mirrors or
       – Note: the unit can continue to
         operate without loss of precision
         even when up to 80% of beam is
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June 8, 2006
      PC-Based Spectral Viewing
• Windows-based software
     – Connect directly via Serial
       Port or via remote modem
• Allows viewing operating
  parameters as well as
  detector signals
     – View/Store/Recall all
       operating settings and
       measurement values
     – Helpful for verifying
       performance as well as
• Copy included free with
  each system

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June 8, 2006
   On-Line Applications For TDL

• Moisture Analysis
     –   Moisture (and CO2) in natural gas pipelines
     –   Moisture in feed to polymer reactors
     –   Moisture in corrosive streams
     –   Atmospheric moisture measurements
• Other IR Absorbing Components

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June 8, 2006
              Typical Measurement
Component                             Minimum Measuring Range
HCl                                  0-10 ppm
HF                                   0-5 ppm
NH3                                  0-10 ppm
CO                                   0-8000 ppm
H2O                                  0-10 ppm
H2S                                  0-300 ppm
CH4                                  0-200 ppm
O2                                   0-2%
HCN                                  0-40 ppm
CO2                                  0-500ppm

* Per meter of optical path length
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June 8, 2006
   Moisture And CO2 In Natural Gas

• Moisture and CO2 are
  important gas quality
  measurements for natural
  gas pipelines
• Typical ranges are:
     – H2O: 4-20 lb/mmscf
     – CO2: 0-10%
• Traditional analyzers subject
  to measurement errors
     – Glycols and amines
     – Measurement drift
• TDL analyzers avoid these
  measurement errors due to
  non-contacting nature of the

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June 8, 2006
     Low Level Moisture In Polymer
       Reactor Feed Application
• Polymer processes, such as
  polyethylene units, require
  monitoring of feed stocks
  for impurities
     – Even ppb levels of
       moisture can damage
• Traditional moisture
  analyzers are slow to
  respond to concentration
  changes and drift over
• Measuring ranges of 0-
  1000 ppb have been
     – LDL of 100 ppb currently
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June 8, 2006
       Other Applications Of High

• Chlorine Processes
     – Moisture, O2 and HCl
• Ethylene Oxide Processes
     – Moisture and ETO
• High Purity Bulk Gases
     – Moisture, Ammonia, etc in pure H2, N2, Air,
       CO2, etc.

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June 8, 2006
      SpectraSensors Customers

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June 8, 2006

• TDL-based analyzers can be a valuable
  new tool for measurement task solutions
• They offer a number of advantages such
  as simple design, fast response and
  reduced interferences with other
• But like all analyzers technologies, TDL-
  based analyzers are not a one-size-fits-all

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June 8, 2006
             Installation Examples

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June 8, 2006

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