Monte-Carlo model of a gas analyser operating under EN 14181:2014 to investigate achievable uncertainty during emission monitoring

Monitoring of emissions is controlled by the Industrial Emissions Directive (IED), which sets out the requirements for emitters to meet. There are standards in place that, when followed, allow the operators to meet the IED requirements. One of these, EN14181:2014, setting out the quality assurance requirements for continuous emission monitoring, has recently been revised. It is assumed that any operator following all the relevant standards (EN15267, EN14181, etc.) will produce data that meets the requirements of the IED. In order to assess the ability of the system to achieve its uncertainty requirements under the IED, the Emissions and Atmospheric Metrology Group at the National Physical Laboratory (NPL) has created a computer model that simulates an instrument operating under EN14181. The model uses Monte-Carlo Simulation to produce an assessment of the overall uncertainty achieved by following the standard to monitor emissions from a typical large combustion plant (LCP). Information from monitoring equipment’s MCERTS product conformity certifi cates is used to produce the parameters for the model, allowing the model to simulate monitoring of any IED substances with different instruments quickly and easily. This talk will briefl y describe the model and some of the initial results, looking at the uncertainty achieved when measuring SO2 with a typical automated measuring system. Future refi nement of the model will include the addition of fl ow monitoring so that it can be used for real time emissions and looking at achieved uncertainty within the EU Emissions Trading Scheme (EU-ETS).