Company Finds Cartridge Dust Collectors to be the Gold Standard (continued)

The New Dust Collection System

The new dust collection system consists of seven Gold Series® (GS) reverse-pulse cartridge-filter dust collectors. Six of the dust collectors are installed side by side on a custom-built support structure to remove dust from the production facility, and the seventh dust collector is installed on a custom-built support structure near the treatment area to remove the dust containing the herbicides and insecticides.

All seven dust collectors use round Gold Cone HemiPleat® cartridge filters with PTS-PolyTech Standard filter media. Each filter has an injection-molded inner cone in its center, which increases the media area and provides uniform dispersion of reverse-pulsed air during cleaning. The filter media is a proprietary blend of cellulose and polyester fibers with a moisture-resistant silicone treatment for optimum dust release. The filter media's open-pleat design increases the media's filtration efficiency, extends the media's service life, and produces a lower pressure drop compared to other standard filter medias.

Of the six dust collectors that service the facility, one is used for general housekeeping and is connected to 52 pick-up points inside the facility (excluding the treatment area) to remove fugitive dust generated at the material-transfer points. This unit, called a GS24 dust collector, contains 24 cartridge filters.

The engineering firm designed and built platforms around the dust collectors and stairways, allowing operators easy access for maintenance checks and filter changes.

The other five dust collectors are each connected directly to one of the conditioning machines located inside the facility. Three of the dust collectors are GS12 dust collectors, each with 12 round cartridge filters. The other two dust collectors are GS16 dust collectors, each with 16 round cartridge filters.

All six dust collectors function at the same time, generating a total airflow of around 90,000 cfm. To prevent the dust collection system from creating a negative air pressure zone inside the facility, the engineering firm installed wall louvers that allow fresh air into the facility.

During operation, air and dust particles are pulled in horizontally through a dust collector's side toward the vertically installed cartridge filters, which hang down from the unit's top. As the dirty air passes through the cartridge filters, the large dust particles fall to the unit's bottom hopper and the small dust particles become entrained in the filter media so that clean air discharges out of the unit's top through an exhaust fan. The cartridge filters remove 99.99 percent of particles down to 0.5 microns, ensuring that Pioneer meets the EPA's dust emission standards. And by having the fan on the unit's clean-air side pulling air through the unit (called a negative pressure system), rather than on the dirty-air side pushing air through the unit (called a positive pressure system), an efficient, low horsepower fan can be used and maintenance requirements are reduced because only clean air passes through the fan.

To keep the filters clean, each dust collector has a reverse-pulse air system that directs short air blasts at a filter's backside, knocking off dust particles from its front side and sending them to the unit's bottom hopper. Each dust collector's cartridge filters are installed in multiple-filter rows. For example, the GS24 has six rows four filters deep, totaling 24 cartridge filters. The reverse-pulse air system sequentially pulses one row at a time, repeatedly cycling through the rows. The pulse system's cycling sequence, pulse rate, and pulse duration are programmed based on an application's requirements.

After the dust falls to a dust collector's bottom hopper, a rotary valve continuously meters it into a 60-footlong, 9-inch-diameter, enclosed discharge auger that runs the length of the support structure. The engineering firm installed a rotary airlock in each dust collector's bottom hopper to ensure that air is only pulled from inside the facility and to prevent the dust from being pulled back into the dust collectors from the discharge auger. The discharge auger moves the dust from all six dust collectors to a 42-foot-tall bucket elevator, which discharges it into a 30-foot-long, 9- inch-diameter, enclosed auger that moves it into an elevated 10-foot-diameter storage bin. The augers and bucket elevator operate continuously when the dust collection system is on.

When the storage bin nears capacity, an operator drives a truck underneath the bin and opens the bin's discharge gate, allowing the dust to gravity-discharge into the truck. The operator then drives away and disposes of the dust at a landfill.

The stand-alone treatment-area dust collector is a GS12 dust collector with 12 cartridge filters. This dust collector, which functions just as the other six do, only operates when the seeds are being treated with herbicides or insecticides. Since the dust this unit collects is considered hazardous and must be kept separate from the other dust, this unit discharges into a large box via a rotary airlock for disposal according to special requirements.