55 i Direct Methane & Non-Methane Hydrocarbon Analyzer

Make automated measurements of methane and non-methane hydrocarbons with the Thermo Scientific™ Direct Methane & Non-Methane Hydrocarbon Analyzer, Model 55i. Unlike instruments that measure only methane and total hydrocarbons, this back-flush gas chromatography (GC) system provides a direct measurement of non-methane concentrations.

Key Features:

Automated batch analyzer repeatedly collects and analyzes small amounts of the sample stream drawn in by the pump. Central to the instrument’s operation is an eight-port, two-position rotary valve which is used to introduce the gas sample into the analyzer and to control the flow of gases through the chromatographic column. The proprietary column design is unaffected by the oxygen content of the sample and provides complete recovery of low volatility compounds while achieving absolute separation of methane from all C2 compounds.

  • Adjustable ranges
  • Real-time correction of THC readings
  • Automatic flame sensing and ignition
  • Automatic calibration and span check
  • 70-second analysis
  • In-line particulate filter

iSeries Advantage:

    • Ethernet connectivity for efficient remote access
    • Enhanced user interface with one button programming and large display screen
    • Flash memory for increased data storage and user downloadable software
    • Enhanced electronics design optimizes product commonality
    • Improved layout for easier accessibility to components



Preset ranges0-5, 50, 500 ppm, or 0-10, 100, 1000 ppm, or 0-20, 200, 2000 ppm, or 0-50, 500, 5000 ppm Group selectable at time of order
Zero noise0.025 ppm RMS (300 second averaging time)
Minimum detectable0.050 ppm CH4-0.050 NMHC as propane
(300 second averaging time)
Zero drift (24 hour)Auto-zero each cycle
Span drift (24 hour)< 2% Span value (without auto calibration)
Response time (90%)~ 70 seconds
Precision2.0% of reading or 50 ppb (whichever is larger)
Linearity+/-2.0% of span (at concentrations of 10% to 100% of span
Sample flow rate0.5 lpm, minimum
Makeup air flow rate275 cm3 to 350 cm3 hydrocarbon free air
Fuel flow rate25 cm3 to 50 cm3 Hydrogen or ~100-150cm3 H2/He mixture
Carrier gas flow rate35 cm3 to 70 cm3 nitrogen
Operating temperature15°C to 35°C
Power requirements100 VAC, 115 VAC, 220-240 VAC +/-10%, 50/60Hz, 420W
Size and weight16.75″ (W) × 8.62″ (H) × 23″ (D), 60 lbs. (17.7 kg)
OutputsSelectable voltage, RS232/RS485, TCP/IP, 10 status relays, and power fail Indication (standard). 0-20 or 4-20 mA isolated current output (optional)
Inputs16 digital inputs (standard), 8 0-10Vdc analog inputs (optional)