Collecting dry fertilizer dusts from manufacturing and packaging operations is a major operations priority. Mears had used various types of dry “bag house” equipment, but results had been unsatisfactory.
For a new installation, the company was determined to avoid bag houses. The area where the new equipment would be installed had high humidity levels, so dry collectors were ruled out because they plug 'blind' in moderate-to-high-moisture environments.
Other factors included high dust loading, dust composition that was very fine (4-5 microns) and highly hygroscopic, and the recovery of collected material.
Modeling showed that a Whirl Wet was the best alternative. Whirl Wet has a long track record for collecting soluble and insoluble dusts at efficiencies between 99% and 99.8%. It does not have external pumps or recirculation devices, or internal moving components. Nothing moves inside the unit, except air.
Whirl Wet employs a unique process to create intense mixing of the dust particles and water. To infuse dust particles with water droplets, the mixture is passed under high velocity through a fixed-position, dual-opposed blade configuration. To increase turbulence, a tangential airstream is injected into the lower blade assembly. Rotation is accelerated, droplets in the airstream are isolated by an integral mist eliminator positioned downstream, and particulate is deposited on the bottom of the unit for recovery (or disposal). Water levels are maintained automatically.
The Whirl Wet is self-cleaning. And because the unit is manufactured of solid polypropylene, no lining, coating or reinforcement is ever needed. The unit is housed in a semi-heated room, and water is not heated. There is no ramp-up required; the system is at full operating potential at the moment of start-up.
Whirl Wet units are manufactured in mild and stainless steels, PVC, FRP and polypropylene. The free sulfuric acids involved in fertilizer formulas made solid polypropylene the best construction choice for the Whirl Wet due to polypropylene’s resistance to corrosives.
In its first ten weeks in operation, the Whirl Wet system collected the “face powder-fine” dusts from Mears’ processing lines at efficiencies averaging of 99.5% and higher. Beyond the benefits of clean indoor air and highly efficient material recovery, the company benefits from simpler, less costly housekeeping.