In Germany, the American company Allied Signal Polymers produces polyamide fibers, among other things, which are sold as material for further processing.
During the production process, the synthetic fibers are spun to long threads which are cooled by a humid airflow. For this purpose, the air stream is blown through fine-atomized water. With polyamide fibers entering the water, high algae growth develops, leading to blockage of the nozzle system. By adding a biocide, the algae growth is restricted, but there are extremely sticky flocks of dead biomass developing, which block the bag and sieve filters (which were used before) after 2-4 hours. Backwash filters also get blocked after a few hours.
A pilot installation determined that a filter fineness of 100 µ is sufficient for a good filtration result, but in order to avoid clamping of the filter disks it was necessary to backflush (time-controlled) every 15 minutes. For the cooling circuit with a volume of approximately 264,000 gallons, a 440 gal/min filter plant was installed in by-pass. An AAF system with two parallel operating 6 x 2" batteries was installed, which has been operating since 1999.
System: Two 6 x 2" Spin Klin AAF batteries
Filtration Grade: 100 µ
Flow Rate: 440 gal/min side stream out of a 264,170 gallon system