Development and Tests of a Combined Filter for NOx, Particulates, and SO2 Reduction

The idea of this innovative filter concept is to combine three individual flue gas technology treatment systems into one product to be more economic and efficient. The central part of the filter is a ceramic filter candle, which is used for common dust separation. The ceramic filter material is activated with modified catalysts to enable selective catalytic reduction at low temperatures (150–200 °C). To reduce acid components while simultaneously increasing dust separation, the activated filter candle surface is precoated with an absorbent. The developed filter is suitable for many applications, especially decentralized applications such as solid biomass combustion or utilization of biofuels in combined heat and power engines, which are target markets. The production of the filter material and the practical test using exhaust gas from a dual fuel engine operating with biofuels are described. A filter concept was developed and tested with the goal to reduce soot, NOx, and SOx emissions in one process step at low temperature levels (150–200 °C). The developed filter is able to meet the strict emission limit values that will be set for combined heat and power plants in the future.