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Online Gas Chromatograph
Precision online gas chromatography for biogas, CBG and biomethane — with TCD and FPD detectors and automatic calculation of calorific value, density and Wobbe index.
TCD + FPD detectorsCH₄ · CO₂ · O₂ · N₂ · H₂SISO 6976 calculationsLAN / USB / RS232
5
Key components measured
0.01 – 100%
CH₄ & CO₂ measuring range
> 1 ppm
H₂S detection level (FPD)
Up to 4
Injectors & detectors (expandable)
Overview
Laboratory precision, running online
A gas chromatograph separates a gas sample into its individual components and measures each one precisely. For CBG producers, it is the reference instrument for proving gas quality, calculating energy content for billing and meeting grid-injection requirements.
Our online GC combines a thermal conductivity detector (TCD) for major components with a flame photometric detector (FPD) for highly sensitive H₂S detection, automatic pneumatics, a 7" multi-touch display and dual-channel chromatography software with natural gas / biogas analysis.
Technical specifications
System, detectors and data
General system
Application
Online gas chromatograph
Configuration
Single-channel GC base unit
Pneumatics
Automatic, electronic pressure control
Injectors / detectors
1 each, expandable up to 4
Sampling valves
6-port (injection & column switching); 10-port optional
Display
7" multi-touch display
Gas measurement
Methane (CH₄)
TCD, 0.01–100%
Carbon dioxide (CO₂)
TCD, 0.01–100%
Oxygen (O₂)
TCD, ppm–25% (molecular sieve 5Å column)
Hydrogen sulphide (H₂S)
FPD, minimum detectable level > 1 ppm
Carbon monoxide (CO)
FPD / TCD, 0–500 / 1,000 ppm
Nitrogen (N₂)
Calculated from measured composition
Calculated parameters
Standard
As per ISO 6976
Parameters
GCV, NCV, density, specific gravity, MMBTU
Analysis extension
Natural gas / biogas analysis (NGA)
TCD detector
Filaments
Four Re/W hot-wire filaments
Temperature stability
0.1°C
Response time
5 min
Noise / drift
0.5 mV / 40 mV per hour
Linearity
> 10⁵
Flow protection
Detector shuts off automatically if flow stops
FPD detector
Application
Hydrogen sulphide and sulphur compounds
Principle
Combustion in hydrogen-rich flame, photomultiplier detection
Sulphur sensitivity
< 6 pg S/s
Max. temperature
350°C
Sample, utilities & data
Sample
Clean and dry; GC inlet 800 mbar–1.1 bar
Carrier gas
Argon 99.999%; FPD gases H₂ & air 99.999%
Carrier consumption
Approx. 15 mL/min
Calibration gas
CH₄/CO₂/N₂/O₂ mixture
Installation
Safe area, +5°C to +50°C, air-conditioned / ventilated
Connectivity
LAN, USB or RS232; up to 32 signals
Key features
Why an online GC
Continuous Online Monitoring
Biogas and CBG composition tracked round the clock.
Accurate & Repeatable
Consistent results for quality control and billing.
Energy Calculations
GCV, NCV, density and specific gravity per ISO 6976.
Optimize Upgrading
Improve purification and overall plant performance.
FAQ
Frequently asked questions
Q.Why use a GC instead of a simple analyzer?
A GC separates and measures each component individually, including nitrogen by calculation, so it can compute calorific value, density and Wobbe index for billing and grid injection — something simple sensor-based analyzers cannot do.
Q.Is it suitable for grid injection?
Online GC analysis with ISO 6976 energy calculations is a core requirement of PNGRB guidelines for CBG injection. We configure the GC for your specific injection agreement.
Q.Which detectors are included?
A TCD for major components (CH₄, CO₂, O₂) and an FPD for highly sensitive H₂S detection.
Q.What utilities does the GC need?
A clean, dry sample at about 1 bar, argon carrier gas, hydrogen and air for the FPD, and an air-conditioned safe-area installation.
Need lab-grade analysis online?
Talk to us about GC configuration for your plant.
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