Abstract Submission - Dr Marc Coleman - National Physical Laboratory
Demonstrating Equivalency of an Alternative Method for SO2 Monitoring at NPL's Stack Simulator Facility using a Broad Range of Analytical Techniques
We report results from a trial at the National Physical Laboratory (NPL) Stack Simulator Facility of a new alternative method (AM) drafted by the UK’s Environment Agency for monitoring SO2 emissions from flues and stacks. The Stack Simulator Facility is a life size replica typical of the last 2 m (ca. 300 L) of a stack, it is constructed with two pairs of opposing 5” BSP sample ports allowing cross-stack measurements or sampling with up to 4 sample probes. A wide range of test gases can be generated including the addition of up to 25% water vapour and variable oxygen, flow rates of 12 ms-1 and temperatures of 180 °C are possible.
Test mixtures of 3 to 250 ppm of wet SO2 were generated in the simulator and measured following EN14791a, the standard reference method (SRM) for SO2, using an NPL procedure accredited under EN17025b. The alternative method was carried out in accordance with TS14793c using 8 analysers covering the following techniques; NDIR, FTIR, IRGFC, EC, UV-GC. All requirements of TS14793 were met demonstrating equivalency of the AM to the SRM, furthermore, considering the analytical techniques individually it was found that all conformed to the performance requirements.
a. Stationary source emissions. Determination of mass concentration of sulphur dioxide. Reference method.
b. General requirements for the competence of testing and calibration laboratories.
c. Stationary source emission. Intralaboratory validation procedure for an alternative method compared to a reference method.
