Continuous emission monitoring systems (CEMS) 

CEMS are used as a tool to monitor flue gas for oxygen, carbon monoxide and carbon dioxide to provide information for combustion control in industrial settings.

They are currently used as a means to comply with air emission standards.

Facilities employ the use of CEMS to continuously collect, record and report the required emissions data.

Envisaged analyses could be for example:

  • HCl (hydrogen chloride),
  • Cl2 (chlorine),
  • NOx (nitrogen oxides), 
  • SOx (sulfur oxide),
  • CO (carbon monoxide),
  • TOC (total organic carbon).

 The standard CEM system consists ordinary of; 

  • a sample probe,
  • a filter,
  • a sample line,
  • a gas conditioning system,
  • of course a calibration gas system,
  • and at least a series of gas analyzers for monitoring of the required parameters.

In monitoring the emissions, the system must be in continuous operation and must be able to;

  • sample,
  • analyze,
  • and record

data at least every 15 minutes and then averaged hourly. That means the operation frequency can be either continuous operation or activation at a predefined frequency or upon demand.