PEMS – Predictive Emission Monitoring System


Ecoxy designs, models and implements PEMS for continuous predictive monitoring of emissions to air from all types of combustion processes such as gas turbines, reciprocating internal combustion engines, boilers and furnaces.  The preconditions are that the combustions process runs on a defined fuel and is sufficiently instrumented. In most cases the installed instrumentation for operation is adequate.

Ecoxy has performed pre-studies for customers to verify whether a PEMS can be established and to define the requirement for additional instrumentation.

A  PEMS is an empirical computer model (neural network) based on relations between the quality of air and fuel supplied to the combustion and the operating parameters of the process on one side and emissions to air on the other.  Typical operating parameters are pressures, temperatures, loads and speeds. When the model is established, the emissions to air can be predicted continuously with accuracy similar or better than physical Continuous Emission Measurement Systems (CEMS)

Ecoxy delivers integrated PEMS projects comprising:

Recording of operational data and emission data

Engineering and establishing of the PEMS models

Documentation of accuracy

User documentation

The pre-condition for an accurate PEMS is simultaneous recording of operational data and exhaust gas analysis of accredited quality. These data are then used to establish the model.  Ecoxy is accredited according to a range of international standards for measurement of emissions to air.

A  PEMS is to some degree tolerant to erroneous input data. Measured values used in the model can be validated and erroneous values substituted with expected values in the emission calculation.  The Operator will in such events be alarmed. This function contributes to a robust system.

A PEMS requires little maintenance, but verification of the model may be necessary after performance of maintenance which influences the combustion process or as a consequence of authority requirements.
PEMS is defined as Best Available Technique (BAT) in EU’s IPPC Directive for offshore plattforms and is installed on hundreds of emission sources, most of them in USA and Europe.