I am afraid I cannot see many merits to this suggestion. It is common practice to condition (humidify and cool) the gases before entering the ESP by spraying droplets of water into the gas stream in a conditioning tower. This might indeed lead to 80 per cent of the dust load dropping out in the conditioning tower. However in your kiln, the suggestion is not to spray into a tower that will act as an expansion chamber but into the gas riser. You will also cool and contract the volume of the gases, which will have the effect of increasing the draft at the kiln inlet leading to the possibility of higher dust losses from the kiln. I could not advise such a modification and believe that a much more detailed examination of the problem is required.

Our ESP on our long dry kiln (2520tpd) is out of order. A certain company has recommended instead of the ESP to install a water fogging system (droplet size = 10 micron) into the riser pipe of this kiln claiming that 80 per cent of dust passing with exit gases before the ID fan can be suppressed that way. Can you advise us on the merits and/or disadvantages of such a system?

I also don't know the reason why the supplier is insisting on two bag filters. There are many cement mills operating with a single filter and a circuit layout similar to the one you envisage. If you refer the supplier to me I might be able to understand their reasoning. At this stage I cannot.

My Company is planning to install a New Cement Grinding Plant with a capacity of 150tph, The Supplier is insisting to have separate mill ventilation bag filter, and the separator fines to be collected through another bag filter. My idea is to have only one bag filter in common while mill ventilation duct is connected to a static grit separator before this bag filter, and the separator fines are collected through a cyclone collection. I understand the advantages and disadvantages of both systems but what I'm not able to understand is why they are insisting on this.