Important to Know About the HFID Measurement of Hydrocarbons.
A steadily growing number of popular and well known accredited test laboratories for emissions measurements in exhaust stacks around the EU, the USA and in many other countries are fortunately once again clearly opting for the use of non computerized HFID based analyzers without the feature for automatic calibration.
This is amazingly happening in an environment of the existence of almost exclusively computerized gas analyzers for the measurement of other non-organic substances like CO, CO2, SO2 NO, NO2, NOx, O3, NH3 where automatic calibration is an undisputedly good facility.
Organic substances like heavy weight hydrocarbons (TVOC and NMVOC) are known to have a very strong tendency to encode on the inner walls of the sample supply lines and inside of the sample tubing, the sample filter and sample pump inside of the FID analyzer during the sample gas transporting and thus falsify the measured values is called hydrocarbon hang up. Once heavy weight hydrocarbons are condensed inside of sample tubing and inside of the sample containing components of the analyzer it is impossible to measure them because whose measurable molecules “hang” on the inner walls of these sample containing analyzer elements. Therefore the calibration and consequently the measured concentrations could be fatally wrong.
Analyzers which measure non organic samples however are these days almost all without exception equipped with facilities for automatic calibration, which is by far not critical for non condensing sample compounds and yes, it is even desirable.
Condensed hydrocarbons however form so called hang up conditions inside of the sample gas lines and in the HFID analyzers can impossibly be taken into account by automatic calibration facilities because of their unknown concentration hanging up somewhere. The condensed concentrations and the order of their magnitude are simply unknown to the automatic calibration controller and can significantly distort the calibration value. They should however be well known necessary in order to obtain reliable and truthful calibration and measurement results. The hang-up conditions mentioned above only occur during measuring hydrocarbons (TVOC and NMVOC).
J.U.M.’s technique and direct controls for manual calibration strictly without the use of automatic calibration features to measure the total hydrocarbon content in emissions applications by using our HFID based analyzers, without any doubt, is the most a gentle and advanced way of handling a HFID analyzer to intervene quickly and directly into the calibration and measuring process by controlling our analyzer without the use of automatic calibration and a necessarily long lasting and uncomfortably slow and time consuming communication dialog on an analyzer’s digital controls.