Passive radiance mode has no light source: it collects infrared energy from hot gases or heat sources and analyzes these receiving absorpance in order to identify the present concentration of the compounds.
Flare destruction efficiency requires:
The knowledge of the input concentrations of each compound
The emissions of these compounds after combustion
In order to perform these measurements above,the more FTIR models are needed
Some analytical instrument must provide input gas concentrations
The passive FTIR must be able to speciate and quantitate the emitted gas concentrations
