EDK 6700 fuel gas multi-component analyzer 

• BTU/Wobbe content measurement 

• C1-C5 hydrocarbon separation & total gas analysis 

• Continuous flow-through analysis 

• Very fast response

•New technology based on IR TF 

• Any carrier gas or utilities 

• Alternative to GC technique 

• Permanent Span calibration

Online monitoring of calorific value in fuel gases

The Wobbe Index (WI) expresses the heating value (known as calorific value) of gases used as fuels, taking into account the proportionality of calorific value to the specific gravity, or the density ratio between the given fuel gas and air. More precisely, the specific gravity is proportional to flow velocity through a constant orifice size at a constant pressure, and thus proportional to gas calorific value. The ETG 6700 puts continuous Wobbe Index monitoring and control in the hands of fuel gas producers, distributors, or anyone requiring WI readings for process optimization.

Basically the ETG 6700 it’s a Tunable Filter I.R. Analyser is an infrared absorption-based on line monitoring system, configured for measurement of light hydrocarbons (alkanes, alkenes and alkynes). A real-time optical analyser, the ETG 6700 is capable of accurately separating hydrocarbon components, a process which could previously only be performed by gas chromatograph (GC) analysers.

The technology Spectroscopic – Advanced NIR/IR absorption spectroscopy utilises state of the art spectral scanning and chemometric based data processing for exceptionally high accuracy, low cross sensitivity and a very fast speed of response. A flow-through cell utilises a patented spectrometer design for a highly stable and accurate measurement; an advanced Tuneable Filter Spectroscopy Analysis Algorithm delivers industry-leading interference compensation with a permanent span calibration, low cross-interference, high baseline stability and a linear response.

Main Applications Natural gas quality and composition, BTU/Wobbe Index measurement, Fuel Blending and control, Gas turbine,engines,fuel cells, Biogas and Syngas fuel, Blast furnace gases, Biomethane production, Natural gas quality, Air demand for combustion control, Refineries flare stacks, etc….

• Non-Contact Flow-Through Gas Cell 

• No sensor poisoning 

• Long-term stability

ETG 6700 is an infrared absorption based on-line monitoring system configured for measurement of hydrocarbon and VOC gases; including alkanes, alkenes, alkynes, alcohols, aldehydes and aromatics at ppm to percent levels.

Non-Contact Flow-Through Gas Cell 

• no sensor poisoning 

• long-term stability Versatile Optical Platform  

• UV through IR wavelength regions 

• various light sources can be coupled High Etendue Optical System 

• high optical throughput 

• high sensitivity 

• excellent signal:noise 

• fast measurement (<1second) 

• opaque liquid & solid measurement Wavelength Scanning 

• simultaneous multi-compound 

• high stability and selectivity  Figure showing the highly overlapped spectra

ETG 6700 provides selective measurements of the hydrocarbon species and carbon-dioxide, and calculates the calorific value, Wobbe Index and other gas properties in real time.

The ETG 6700 it’s composed mainly by the Tunable Filter Spectrometer which’s capable of high-accuracy fuel gas composition measurements every 5 seconds. The ETG 6700 Gas Analyzer provides selective measurements of the hydrocarbon species and carbon-dioxide, and calculates the calorific value, Wobbe Index and other gas properties in real time. The analyzer provides real-time data through Modbus digital interfaces. 

Other components are : 

• IR Optical Bench for additional measurement of CH4,CO2,CO 

• ARM processor with ETG proprietary SW 

• 5,7 “ Touch Screen Monitor 

• DO module for MPS (Multipoint System ) 

• Analog Output for speciate or Calorimetric value by  4-20 mA 

• Gateway Converter for ModBus, Profibus

The ETG 6700 Gas Analyzer provides an accurate and real-time alternative to gas chromatographs and residual oxygen analyzers for monitoring fuel gas composition and heating value properties including liquid natural gas (LNG), pipeline natural gas, and other fuel gases containing C1 – C5 hydrocarbons. Factory calibrated, the analyzer provides<0.15% relative CV accuracy in LNG type sample containing only C1 – C5 and < 1% error in pipeline natural gas samples containing C6+ heavier hydrocarbons

ETG 6700 Gas Analyzer specifications in Natural Gas Analysis Configuration

Compounds Measured

Methane, Ethane, Propane, n-Butane, iso-Butane, C5 (lumped), CO2 (0-100%) BTU, CV Wobbe Index Precision / Repeatability * < +/- 0.05% (repeatability based upon 5-second averaging)

Accuracy *- Methane (80-100%): +/- 0.2%, Methane (0 – 80%): - +/- 0.5% Ethane & Propane: +/- 0.2% - iso & n-Butane: +/- 0.1% - Pentanes: +/- 0.2% - CO2: +/- 0.2% Zero drift Less than ±0.2% (absolute) per month (zero on air or N2)

Span calibration Factory calibrated (permanent calibration for the life of the analyzer)

Update rate 5 seconds (default) or 1-300second configurable (averaging time improves precision)

Additional channel(s) Contact ETG for additional target gases

Technique Flow through

Flow rate 0.1 – 1 SLPM (up to 15 SLPM available upon request)

Pressure* 0 – 5 psig (up to 100 psia available upon request)

Sample temperature 0-50 °C

Sample connections ¼” SwagelokTM fittings

Multipoints Up 6 differentsampling points

Electrical Signal Output 4-20 mA for each measuredgas or as Wobbe Index

CommunicationProtocol ModBus RTU, ModBusTCP IP,  Profibus, Profinetand others on request

Multisampling System Signal D.O. for each measuredpoint driven by SW

Mechanical dimensions The dimensions dependingby APPLICATION and CONFIGURATION

Weight 18 Kg

Power requirements 100-240VAC 50 Hz

Operating temperature -5°C to + 40 °C

Enclosure Material & Protection SS 304  - IP54

ETG 6700 is the Best Solution :

The simplicity of an NDIR-like hardware package,  with FTIR-like accuracy & specificity, and GC-like speciation without physical separation