Compliance with new flue gas flow rate standards at power stations - Verifying flue gas flow rate calculation at power plant, for emissions reporting purposes, by means of stack testing and data evaluation to EN ISO 16911:2013

Project Number 379

Flue gas flow rate is combined with the reported pollutant concentrations to produce mass release rates for emissions reporting purposes. A new EN ISO standard requires the calibration of flue gas flow meters (when fitted) and the verification of flue gas flow rate calculation (from fuel consumption or energy production). A previous VGB Research Project (338) defined the mandatory calculation method that is incorporated into this standard (in order to ensure the continued acceptance of flue gas flow calculation in line with power industry practice). However, the standard also requires that the plant calculation is verified by means of stack testing using newly defined standard reference methods (SRM). There is a choice of SRM - velocity traverses, using one of three different Pitot types or a vane anemometer - and tracer injection techniques.

If there is significant non-axial flow in the flue, standard Pitots over-estimate the flue gas flow by as much as 20%. There is a need to define the best choice of reference method for testing at both coal fired power plant and at gas turbine plant (existing and new plant). A field trial at each plant type is therefore proposed. It is intended to consider wet stack environments and high swirl levels. There is also a need to have a common approach to the assessment of measurement uncertainty and the statistical analysis of results when verifying the calculated flue gas flow rate from the plant data system which must be reviewed and adapted to also meet the requirements of the standard prior to testing. A Quality Assurance approach will be defined. A spreadsheet tool will be produced for the flow calculation and QA implementation according to this new standard. This project will build on the work already performed by the participants in their member states.

The project is supported by the European Working Group Emissions Monitoring.