Menardi - Hydrolysis

Moisture is the most deadly factor in any dry filtration system. Moisture in this case includes anything that is, or can condense into liquid. Moisture in most cases is not caused by baghouse design but by poor operation or maintenance. Whatever the cause, the moisture is a serious threat to the operation of dry fabric filter systems. With all synthetic fibers except polypropylene there is a chemical action that can occur in the presence of heat and moisture called hydrolysis. This is a chemical absorption of water that changes the polmeric structure. In the process the fiber shrinks and looses almost all strength. Beyond this degradation of the fibers, moisture can trigger chemical reactions of the pollutants. Some of these are exothermic and can melt or burn holes in the filter.

Moisture will wick in any textile. The wicking process, because of heat and airflow, will tend to be into the fibers of the textile structure. The wicking action can and does carry micron and sub-micron particles into the fiber with the liquid. This action destroys the fiberous structure and the ability to filter. We receive many filter units that are returned from the field with complaints of high operating pressures. In about 80% of these cases the cause is ultimately reduced to moisture in the system.