"Glass polypropylene" sounds like overkill if this is simply a packing plant, without high process temperatures.

Ask several filter bag suppliers and compare their offers and recommendations (and prices).

In any case, make sure the compressed air for cleaning is passed through a refrigerant dryer.

Michael Reid. ■

In some cases, notably galvanizing plants, it is necessary to insulate the bag filter and electrically heat the hopper to keep the internals above acid dew point.

I have not heard of the same thing being done for fertilizer dust but perfectly dry compressed air is necessary.

Good Luck,

Michael Reid. ■