Codel International Ltd

- Model GCEM4100 - Multi Channel Extractive Flue Gas Analyser


The GCEM4100 is a hot extractive analyser for difficult flue gas monitoring applications. It uses infrared absorption spectroscopy to measure up to seven pollutant species in a single self-contained unit. Many conventional extractive systems require the sampled gas to be cleaned and dried to a very high standard prior to analysis, invariably resulting in high maintenance costs. Such elaborate pre-conditioning is not required by the GCEM4100. Process gases are continuously drawn through a fine filtered probe installed in the flue gas and transported to the measurement chamber via a heated sample line – without further conditioning.

  • Up to seven gas species
  • ppm, mg/m3 (measured) and mg/Nm3 (normalised)
  • CO, CO2, NO, NO2, SO2, HCL, CH4 & H2O
  • Analogue and serial digital output
  • Real-time normalisation for STP and H2O

Hot extractive multi-channel gas analyser for continuous process and emissions monitoring.

  • Multi-species infrared absorption analyser
  • Accurate, reliable and low maintenance technology
  • Extractive system with full zero & span verification using certified gas
  • Gas temperature and pressure sensors On board normalisation to standard reference conditions
  • Automatic calibration and verification
  • Analogue and digital outputs - Export of data to SCADA, DCS and historian systems


The GCEM4100 hot extractive multi-channel gas analyser is CODEL’s industry-proven continuous emissions monitor for difficult applications. Designed exclusively for use on gas turbines or applications where the flue gas concentration is very low and the temperature is abnormally high.

Three decades of development, knowledge and practical experience have been utilised to produce this advanced technology gas analyser which gives complete flexibility of use on process or emissions applications whilst delivering superb accuracy and repeatability at a competitive price.


Many conventional extractive systems require the sampled gas to be cleaned and dried to a very high standard prior to analysis, invariably resulting in a high maintenance demand. Such elaborate pre-conditioning is not required; the GCEM4100 creates ‘perfect’ duct conditions in a temperature controlled chamber within a separate free-standing, air-conditioned cabinet. Process conditions are extracted using a heated probe system which has an option of compressed air blow-back for excessively dusty applications. Once the sample has been drawn it is simply cooled (or heated) then transferred along a heated sample line, without further conditioning, to be measured using a CODEL multi-channel analyser housed in the cabinet.

Environmental agencies demand that continuous emission analysers have the facility to prove their performance using known concentration audit gasses. The GCEM4100 provides the facility to automatically check and control zero calibration point using clean, dry compressed air or nitrogen. Where independent span checks are required, bottled gases of known concentration can be injected directly into the measurement chamber.


The GCEM4100 analyser is capable of measuring CO, NO, NO2, NOx, SO2, CH4, HCl, N2O, CO2 and H2O simultaneously and with integral temperature and pressure sensors can compute fully normalised data directly in mg/Nm3.

The analyser can be easily incorporated into the CODEL SmartCEM system along with dust, flow and oxygen signals to deliver a complete emission monitoring solution capable of meeting today’s tough legislative demands.

  • Gas Species Options: Maximum 7 gases from: CO - NO - NO2 -NOx - N2O - SO2 - HCl - CH4 and CO2. Gas temperature pressure and H2O for data normalisation are standard.
  • Measuring units: ppm - mg/Nm³ - mg/m³ - %
  • Response Time: Less than 200 Seconds (T90)- MCERTS Specification
  • Ambient Temperature: -20°C to +50°C
  • Power supply: 48V DC from CEMS Control Panel
  • Construction: Corrosion resistant epoxy coated aluminium housing sealed to IP66
  • Analogue outputs: 4-20mA current outputs for each gas channel supplied isolated. 500O load max  fully configurable from software.
  • Logic Outputs: up to 8 x volt-free SPCO contacts  50V 1A max. Configurable as alarm contacts - 1 x volt-free SPCO contact 50V 1A max for data valid signal
  • Serial Data: RS232