There are various benefits of using FLKCAT filters. Click on the points below for more information.
The catalyst and ceramic filter both operate very well at 300 – 350oC. . This temperature is outside the zone where there may be liquid dewpoint excursions and is above the temperature where ABS, Ammonium Bisulphate, is present which can detract from the performance of the catalyst. This is the optimum temperature zone for the deNOx reaction too. This new filter can also be used for reducing SOx. Normally deSOx takes place at around 140oC, an operating temperature which can give corrosion problems as this is at dewpoint conditions. It is not widely known but the deSOx reaction tails off to around 240oC, where, as the temperature continues to rise the efficiency picks up. At 250oC the reaction proceeds at around the same rate as at 140oC, but without the issues associated with liquid formation.
Therefore the 300 – 350oC temperature range gives an ideal zone for all three functions, dust removal, deSOx and deNOx to take place.
The combination of ceramic filter and catalyst also has other benefits. It is well known that in the standard SCR process the performance of the catalyst will tail off as dust which escapes traditional filtration processes coats and physically masks the active catalyst sites. This can be counteracted by regular cleaning of the catalyst but it is unlikely that the original performance level will be recovered. This degradation in performance can be made even worse if the dust contains chemicals that will poison the catalyst. This includes materials such as sodium and potassium salts which are very common in many process gas streams for example in biomass/waste to energy applications and in the glass industry.
By embedding the catalyst within the ceramic filter wall the catalyst is protected against these two mechanisms affecting performance. The ceramic filter is so efficient in removing even sub-micron particles from the gas that there is no contact whatsoever between dust and catalyst. This enhances performance and of course lifetime of the catalyst and negates the need for cleaning and maintenance of the catalyst. This is a very important advantage over the old traditional catalyst systems. One other important advantage is that there is no observable diffusion restriction in catalyst performance. In standard catalytic systems there is a competing gas flow in and out of the pores of the catalyst beads in the SCR. In the new hybrid catalytic ceramic filter the catalyst is finely divided through the body of the filter rather than just coating a ceramic bead surface. This enables nano sized needles of catalyst to be exposed to the gases as they flow through the filter. There is no diffusion in and out of the catalyst and the flow is unidirectional across the catalyst. This in effect increases the catalyst/gas contact opportunities and improves the efficiency of the reaction.