Chemical plant, Cheshire, England. Three MikroPul units with nylon felt filter bags. Design airflow rate 3,000 cfm @ 212ºF; air-to-cloth ratio 6/1.
Filters ran for 6 to 8 weeks at a pressure drop of 6 - 7" w.g. After 10 to 12 weeks, this increased to a 10 - 11" w.g. Filter bags had to then be removed.
Installed GORE® membrane/NOMEX® felt filter bags in all three units. NOMEX backing laminate was used to prevent hydrolysis.
Bag life extended to two years. Operating pressure drop of 4" w.g. Production levels now remain consistently high, giving significant energy savings by producing a set tonnage in a shorter period. The need for frequent shutdown for bag changes had been eliminated.