The use of a bag filter on the cooler airstream will require an additional capital outlay of the order of $1.0 Million. This
could be recouped in energy savings in less than three years.
Provided that the warm air is recycled as dilution air to the dryer combustion chamber, installation of a bag filter on the
equipment vents system is economically very attractive. The upfront capital outlay is about the same as the wet scrubber
option, Annual savings of approximately $450,000 per year can be realized on a 1.0 Million tonne/year DAP plant.
At the very least, bag filters should be strongly considered in a revamp situation when a capacity increase is desired as an
alternate to building more or bigger scrubbers.