Dust Concentration Measurements in Wet Flue Gases Avoiding the Influence of Sulphuric Acid Aerosols on the Measured Value to a Large Extent (Part II)

Project Number 292

In the EU Directives on large combustion plants and on the incineration of waste very low emission limit values for the dust concentration were set. With the implementation of these Directives into national law in Germany (TA Luft, 13. BImSchV and 17. BImSchV) these values were partially tightened. Numerous surveys among power plant operators pointed out that meeting the limit values cannot be guaranteed in all cases. A lot of plants will have dust emission concentrations near the limit values. So a sound dust measurement is very important because even small additional but wrong “dust” findings may result in exceeding the limit values.

In the VGB Technical Committee “Air Pollution and Noise Control” it was reported that considerable virtual dust concentrations because of the influence of sulphuric acid aerosols were measured on gravimetrical dust measurement. In the VGB research project 255 a sampling technique was examined which avoids this effect as far as possible. By using a probe with an adjustably heatable filter head it was reached that the droplets and the dissolved sulphuric acid compounds in the exhausted flue gas flow were heated and could pass the filter gaseously thus not being retented on the filter. Through this the increase of the measurement reading by sulphuric acid aerosols was reduced effectively.

It is the aim of this project to prove the applicability of the developed measuring method for the calibration of dust emission measurement and to implement the method in the relevant standards.

The project is carried out until April 2007 with participation of Vattenfall Europe Power Consult GmbH, E.ON Engineering GmbH and STEAG encotec GmbH. Volker Hamacher, VGB PowerTech e. V., manages the project supported by the VGB technical committee "Air Pollution and Noise Control".