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precisive tfs tunable filter spectrometer
Optical Gas Analyzer, Tunable Filter Spectroscopy, Liquid Natural Gas


  • Measurement Technique
    Tunable Filter Spectroscopy
  • Measurement Channels
    CH4, C2H6, C3H8, i-C4H10, n-C4H10, C5H12, BTU Calorific/heating value, Wobbe index
  • Measurement Ranges
    Methane: 0-100% (C1)
    Ethane: 0-25% (C2)
    Propane: 0-25%(C3)
    n-Butane: 0-10% (nC4)
    iso-Butane: 0-10% (iC4)
    C5 (lumped): 0-5% (nC5, neoC5, iC5)
    Nitrogen: calculated balance
    BTU Calorific Value-CV (computed as per ISO 6976:1995)
    Wobbe Index-WI (computed as per ISO 6976:1995)
  • Repeatability
    Hydrocarbon channels: < ± 0.05% (absolute)
    CV & WI computation: < ± 0.05% (relative of reading)
  • Zero Drift
    Not to exceed 0.2% per month on each hydrocarbon channel
  • Sample Pressure
    0.1-2 psig
  • Flow Rate
    0.1-1 L/min
  • Update rate
    5 seconds (default), software selectable from 1 -120 seconds


Precisive TFS™ Light Absorption Spectroscopy Schematic

Simplified schematic of light absorption spectroscopy

The Precisive TFS™ (Tunable Filter Spectrometer) sensor platform consists of a light source, a sample cell (for gases, liquids or solids), a wavelength separating element (spectrometer) and a photo-detector. The wavelength separating element "slices" the wavelength components of the broadband light source which then interacts with the sample molecules. Some of the wavelength components are absorbed and some are transmitted through without any absorption.

Advanced Spectral Decomposition Algorithm

Light absorption spectroscopy with advanced spectral decomposition algorithm

Precisive TFS™ Tunable Filter Spectrometers use an advanced spectral decomposition algorithm. The resulting spectrum is called absorption spectrum, which acts as "fingerprints" which are used to identify the sample components and/or quantify the composition of the sample.

Precisive® 5-152 LNG Analyzer Benefits

  • Analysis in seconds: Continuous measurement instead of batch handling with quick spot check measurement, minimized sampling issues, and real-time feedback.
  • No re-calibration, no carrier gas requirements: Well suited for loading and unloading measurements with low operational costs.
  • Flow-through sensor design: No sensitivity to pressure and flow variations minimizes potential sampling issues.
  • Small footprint, outdoor rated: Can be mounted on the dock, close to loading area making it well suited for transportable spot check applications.

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