Continuous biogas composition and landfill gas analyser ZPAF

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Biogas composition analysis systems and landfill gas analyser are a critical component of industries like landfill gas power plant, wastewater treatment, waste management, biomass fuel production or agriculture. By monitoring specific components such as methane, hydrogen, sulfide, carbon dioxide or oxygen, they help guarantee the quality and safety of biogas and biomethane while ensuring compliance with environmental regulations and landfill gas monitoring guidelines.

  1. Analyzer for biogas composition: ZPAF model
    1. What are the applications of the ZPAF biogas analyser?
    2. What are the advantages of the ZPAF biogas analyser?
    3. What are the measuring ranges of the ZPAF biogas analyser?
    4. What are the technical specifications of the ZPAF biogas analyser?
    5. How does a biogas analyser work?
  2. Biogas composition and quality analysis system in an industrial environment: ZPSB system
    1. What are the applications of biogas analysis systems?
    2. What are the advantages of the Fuji Electric biogas analysis system?
    3. What are the technical specifications of the Fuji Electric ZPSB biogas analysis system?
  3. Enjoy the expertise and services of Fuji Electric



Analyzer for biogas and landfill gas composition: ZPAF model

analyzer for biogas compositionAccurate continuous and simultaneous measurement of the biogas composition.





The Fuji Electric ZPAF biogas analyser continuously and simultaneously measures the 4 main components of biogas and landfill gas:

Methane (CH4)
Carbon dioxide (CO2)
Oxygen (O2)
Hydrogen sulFide (H2S)


The biogas analyser is unique in the market due to its design and performance

  • Compact and robust device
  • Guaranteed accuracy
  • Continuous measurement including landfill gas H2S


What are the applications of the ZPAF biogas analyser?

  • Measurements upstream and downstream of biogas treatments
  • Landfill and landfill sites
  • Landfill site for final waste
  • Digester and agricultural fermenter
  • Waste treatment plants and incinerators
  • Sewage and wastewater treatment plant
  • Methanisation plant and site
  • Cogeneration and biogas engine
  • Biomass
  • Biofuel plant


What are the advantages of the ZPAF biogas analyser?

  • Easy maintenance thanks to self-diagnostic functions
  • Good accuracy and excellent stability of the measurement over time
  • Large backlit display
  • Automatic zero and span calibration
  • Digital link to Modbus® protocol


What are the measuring ranges of the ZPAF biogas analyser?

The Fuji Electric ZPAF Biogas Analyser measures the biogas components with the ranges shown in the following table:

Measuring ranges
 1st range2nd rangePrinciple
CH4 METHANE0…20% vol0…100% volSingle-beam NDIR
CO2 CARBON DIOXIDE0…20% vol0…100% vol
H2S HYDROGEN SULFIDE0 ... 500 ppmO ... 2000 ppm   or   0 ... 5000 ppmConstant-potential electrolytic
O2 OXYGENO ... 10% vol0 ... 25% volGalvanic fuel cell


What are the technical specifications of the ZPAF biogas analyser?

The Fuji Electric ZPAF biogas analyser has the following technical specifications and metrological performances:

Technical specifications
Repeatability≤ ± 0,5 % FS (H2S : < ± 2,0 % FS)
Linearity≤ ± 1,0 % FS (H2S : < ± 2,0 % FS)
Zero drift≤ ± 2 % FS per week
Span drift≤ ± 2 % FS per week
(H2S : ≤ ± 2,5 % FS per week or ≤ ± 5 % FS per week)
Response time (for 90%)10-30 s (H2S: 180 s)
Output analogue4-20 mA DC or 0-1 V DC
Contact input12-24 V DC, < 9 points
Contact outputSPDT, < 15 points
Communication (option)RS-485 (Modbus)
DisplayBacklit LCD
Power supply voltage100-240 V AC, 50/60 Hz
Dimensions and weight483 (L) x 133 (H) x 382 (P) mm, approx. 9 kg


How does a biogas analyser work?

To measure the composition of the biogas, a biogas analyser uses different analytical methods depending on the component to be analysed.

How to measure methane (CH4) and carbon dioxide (CO2) in biogas?biogas-analyser-zpaf-schema-optique-bench-ndir

CO2 and CH4 are measured using non-dispersive infrared (NDIR) absorption technology.
The measurement principle of an infrared gas analyser (NDIR) is described on the Fuji Electric multi-gas infrared analyser page.



How to measure oxygen (O2) in biogas and landfill gas?

O2 and landfill gas oxygen are measured by the electrochemical method.


The measurement principle of the electrochemical O2 cell is as follows:
Two electrodes are enclosed in the cell filled with electrolyte. When biogas enters the cell, a chemical reaction occurs, generating a flow of electrons and thus an electric current, proportional to the amount of oxygen present in the biogas.





How can hydrogen sulFide (H2S) in biogas and landfill gas be measured continuously?

H2S is measured by the electrolytic method at constant potential.

principle-diagram-constant-potentiel-electrolytic-measurement-biogas-analyserTwo chemical reactions are required for this method.
The H2S to be measured reacts with the moisture (H2O) present in the cell at the working electrode.

Reaction at the working electrode
H2S + 4H2O --> H2SO4 + 8H+ + 8e-

In the same time, at the auxiliary electrode, a second reaction takes place between the oxygen (O2) also present and the hydrogen ions (H+) generated by the first reaction.

Reaction at the auxiliary electrode
O2 + 4H+ + 4E- --> 2H20


The flow of electrons varies in proportion to the amount of H2S present in the cell.
For both reactions to take place, it is therefore necessary that the cell contains not only the H2S to be measured but also a minimum of oxygen and moisture.
The Fuji Electric ZPAF analyser measures H2S continuously because it is provided with an automatic regeneration system for the H2S measuring cell.









Since the H2S measuring cell uses the electrolytic constant potential method, it is imperative to include oxygen and moisture in the gas to be analysed. With this automatic regeneration system, ambient air is supplied to the transmitter at regular intervals to allow the analysis of the biogas, which is often oxygen-free and dried out before analysis.


Biogas composition and quality analysis system in an industrial environment: ZPSB model

High-stability and ease-of-maintenance incorporated in a space-saving design

Fuji Electric helps preserve our environment and save natural energy.

Accurate continuous measurement of biogas composition. Up to 4 components including H₂S measured continuously and simultaneously.

H2S  -  CH4  -  CO2  -  O2 - Pressure - Temperature - Flow
Stand alone cabinet  -  Wall mounted cabinet





The ZPSB biogas analysis system is part of the Fuji Electric Biogas Measurement Package including:


What are the applications of biogas analysis systems?

Biogas production and processing sites are subject to environmental constraints in terms of corrosivity and toxicity (presence of H2S), explosivity (presence of CH4), but also potentially high thermal stress and dust.
The Fuji Electric ZPSB biogas analysis system has been designed to measure the composition of biogas at industrial sites such as non-hazardous waste landfills (NHWL), sewage treatment plants and anaerobic digesters and fermenters. The landfill gas analyser allows the landfill gas management and landfill gas monitoring.

These applications include:

  • Landfill gas capture and collection
  • Landfill gas of municipal solid waste
  • Landfill gas power generation
  • Landfill gas processing plant
  • Landfill gas to energy plant
  • Agricultural fermenters and digesters
  • Facilities for waste management and incineration
  • Methane production site and facility
  • Biogas-powered cogeneration systems
  • Landfill gas of biomass
  • Bioenergy production facility


What are the advantages of the Fuji Electric biogas analysis system?


  • Proven Fuji Electric optical benches to reliably measure CH₄ and CO₂ gases using the NDIR method in an industrial environment
  • Specific protection of optical elements to withstand H₂S gas and other aggressive components
  • Fuji Electric Sample Switching technology for a long life of the H₂S cell without dilution
  • Automatic calibration (optional)



Proven excellent performance of Fuji Electric gas analysers

  • ZPAF biogas analyser using the latest NDIR technology
  • Optimum reduction of cross-interference



Simultaneous & continuous measurement of CH4 , CO2 , O2 and H2S

  • Wall-mounted or standalone analyser cabinet depending on selected options
  • Easy and fast installation and commissioning



Flexible solutions that fit the specificities of the site

  • Metal or polyester cabinet for outdoor installation
  • Industrial biogas, landfill gas sampling system (high humidity, dust and corrosion) suitable for each application
  • ATEX heated sample line (optional)
  • Two measuring ranges per component
  • Multipoint sampling system with Fuji Electric touchscreen HMI interface (optional)


Safety options

Flexible solutions that adapt to the specifics of the site

  • LEL detection, light alarm, mains power shut-down and biogas inlet closure
  • Flame arrestor at biogas inlet







See all the benefits of the Fuji Electric ZPSB biogas analysis system.


What are the technical specifications of the Fuji Electric ZPSB biogas analysis system?

The ZPSB biogas analysis system incorporates the ZPAF biogas analyser. It has the following technical features:

Measured components1 to 4 measured components: CH4 / CO2 / O2 / H2S
TechnologyCH4 / CO2NDIR
O2Galvanic cell sensor
H2SConstant potential electrolytic sensor
Measurement RangesCH4 / CO20 - 20 %vol0- 100 %vol
O20 - 10 %vol0 - 25 %vol
H2S0 - 500 ppm0 - 2000 ppm   or   0 - 5000 ppm
Power supply100 to 240 V AC 50/60 Hz
DisplayBacklit LCD display (Standard)
Fuji touch panel interface (Multipoint Sampling Option)
Displayed informationStandard: Measured components, concentrations, alarms, configuration menus, calibrations and advanced diagnostics
Option: Advanced functions with multipoint sampling (see multipoint system option)
DimensionsStandard Single Point Wall mounted cabinet: 750(W) x 750(H) x 500 (D)
WeightStandard Single Point Wall mounted cabinet: 50 kg
StructureStandard Single Point Wall mounted cabinet: consolidated polyester cabinet for outdoor use



Response timeCH4 / CO2 / O2≤ 30 sec
H2S (0 - 2000 ppm)≤ 180 Sec
H2S (0 - 5000 ppm)≤ 300 sec
RepeatabilityCH4 / CO2 / O2≤ ± 0,5% PE
H2S≤ ± 2% PE
LinearityCH4 / CO2 / O2≤ ± 1% PE
H2S≤ ± 2% PE


Inputs / Outputs

Analog Outputs4 - 20 mA (one analogue output per component)
CommunicationStandard: Concentration measurements and status signals (alarms, calibrations) RS485 Modbus RTU
Option: Ethernet Modbus IP (multipoint sampling)
Digital OutputsStandard: Dry contact general alarm including analyser fault and sampling system fault
General Alarm light indicator on cabinet front door


Environment conditions

Ambient temperature-5 °C to +40 °C
Ambient humidity90% RH max


Biogas sample conditioning

SamplingPTFE or Stainless Steel tube
4 to 6 mm internal diameter
Option: ATEX heated line
Biogas PressureSampling pump for ambient pressure or low-pressure biogas (< 100 mbar g)
High-pressure biogas: system with pressure reducer
Single point systemContinuous measurement of a single stream: sampling, dryer, filtration, bypass, flow adjustment, H2S absorption (option)
Multipoint system (Optional)Additional advanced features:
Fuji Touchscreen interface and PLC
Configuration of the number of components measured (max. 4)
Configuration of the number of biogas streams analyzed (max. 6)
Configuration of stream switching sequence, measurement times, purge times
Automatic or manual switching setting
Display of the 4 (max) measured components concentrations of the 6 (max) analyzed streams
Display of sampling and analyser alarms
Modbus output of the measurement, status and alarms
Analog outputs and digital outputs (option)



Enjoy the expertise and services of Fuji Electric