Cement Finish Mill, Conventional Mechanical Separator

The system is comprised of a conventional mechanical separator and a rotary ball mill. The baghouse provides mill sweep and separator ventilation. Production was limited to 83 tons per hour due to blinding of conventional polyester felt filter bags and bag life averaged one year. Actual airflow was 28,700 acfm at 204ºF at a differential pressure of 8 to 10" H2O and a 2.8:1 air-to-cloth ratio. Design airflow was 51,000 acfm at 185º F and a 5:1 air-to-cloth ratio.

GORE® Membrane Filter Bag Experience

Collector Designation: 10-64
Collector Manufacturer: Flex-Kleen
Process Description: Mill sweep/separator ventilation
Model Number: 100-WM-780
Particulate Collected: Finished cement
Design Airflow Rate: 51,000 acfm
Design Temperature: 185º F
No. Bags/Compartment: 60
Inlet Grain Loading: 160 gr/cf max.
No. Bags/Collector: 780
Particulate Bulk Density: 60-80 lbs/cf
Bag Dimensions: 6" dia. x 100" long
Inlet Velocity: < 4,000 feet per minute
Cleaning System: Pulse jet
Bag Material: GORE-TEX® membrane/ heavy duty polyester felt (16 oz/yd2)
Top of Bag Configuration: Grooved snap band
Air-to-Cloth Ratio Design: Net 5:1
Date Installed: 1st set: March 1989
2nd set: March 1993

The GORE® membrane filter bags operated consistently at 4-5" w.g. at an air-to-cloth ratio of 5.0:1. Through the use of GORE® membrane, mill production increased 8% to 90-92 tons per hour, as better mill sweep was achieved. The energy and maintenance costs were substantially reduced over conventional bags. The first set of GORE® membrane filter bags was installed for four years and was replaced with a second set of GORE® membrane filter bags. The second set has performed for five years to-date and the plant has a third set on order.