I cannot foresee that reduces the load of dust entering a filter will have any detrimental effect on its performance. Certainly no problem with an ESP. Your point regarding fine dust blinding the cloth of fabric filters may be valid, but I would be surprised.

In an air-swept mill false air is usually introduced at the bottom of the ascension pipe in order to ensure there is sufficient volume, density and velocity of air to lift the ground material up the ascension pipe and through the separator. The amount of dust being carried up the ascension pipe is the same, however the volume of air is greater therefore the overall effect is a dilution of the dust load. In principle the false air will cause a reduction of the temperature and this will reduce the resistivity of the dust improving the electrostatic precipitation.

Do you think that pre-dedusting in a raw mill circuit by means of cyclone with a separation efficiency of 91-93 will have negative influence on the raw mill bag filter or ESP in regard to the fact that after pre-dedusting only rather fine grain and rather low quantity of dust will enter the filter? Could it become difficult to clean the bags due to fine dust getting deeper into the pores of the filterbag and could the fine dust have negative influence on the ESP?

I am a consultant to the petroleum coke industry. There is a lot of talk that high sulphur pet coke (7-8 per cent) is a low cost feed to cement plants that meets US emission standards. The theory is that the suphur is thoroughly consumed or bound up by the limestone and converted to calcium sulphate. I have been recently asked by a US cement plant contemplating burning coke for more specific information in order for them to meet their EPA permit. Do you have anything re solid scientific statistics of the SO_x formation in cement kilns when burning coke??