Dust Collection for Seed Separation and Processing

• Threshing and pre-cleaning (winnowing, scalping, debearding)
• Drying
• Basic and fine cleaning
• Grading (e.g., gravity separation)
• Seed treatment/seed coating (film coating, pelleting, encrusting)
• Seed packaging

Seed processing and conditioning equipment includes:

• Cleaners
• Length separators
• Gravity separators
• Precision sizing equipment
• Destoners
• Grain dryers
• Debearders
• Feed milling equipment
• Film coating systems

Material handling and packaging equipment used for seeds and grains include:

• Bucket elevators
• Belt conveyors
• Vibrating conveyors
• Continuous cup elevators
• Drag conveyors
• Bagging scales
• Bulk storage systems/grain silos

Combustible Dust Control
Combustion risk is the number one concern in the seed conditioning industry, and the dust collector must be designed accordingly. This may include elements such as:

• explosion vents for safe venting of the energy from a dust collector explosion
• isolation valves to prevent a pressure wave from propagating back into the facility
• rotary airlock to prevent dust in the collection bin from being used to fuel an explosion
• heavy-duty doors and side panels

Bin Venting
Seed and grain storage will require a bin venting dust collector. The dust collector is mounted directly to the top of the bin, hopper or silo to collect airborne particulate within the enclosure. Bin venting is necessary to prevent a combustible dust explosion within the storage unit. Both the silo/storage bin and the dust collector must be equipped with deflagration vent panels for safety.

Space Constraints
Seed conditioning towers and seed processing facilities may have limited space for a dust collection system. Cartridge-style dust collectors are more compact than baghouse dust collectors and well suited for most seed conditioning processes. Look for space-saving features such as:

• Modular design, which allows the unit to be designed to meet specific space requirements (e.g., vertical vs. horizontal design).
• Advanced filter design (with more usable filter media per cartridge), which enables a more compact design for the dust collector.

Environmental Considerations
If the dust collection system will be outdoors, the dust collector cabinet and ductwork must be built to withstand the elements. Look for:

• Heavy-duty cabinet construction with powder coating inside and out.
• Ductwork materials and tubing designed for heavy-duty use in outdoor environments. Instead of poly tubing, the dust collector may need copper or stainless steel tubing that will withstand heat, moisture and UV exposure.

Abrasive Dust Control
The abrasive nature of some seed conditioning dusts, along with high overall volumes of dust, creates special challenges for the design of the dust collection system. Dust collectors for seed conditioning processes producing abrasive dust are likely to require modifications to protect the filters and extend the life of the dust collector. These modifications may include:

• Abrasion-resistant air intakes
• Drop-out boxes to allow coarse, heavy dust to fall out of the airstream before it hits the filters
• Baffles within the ductwork, intake and filter cabinet to protect the filters
• High-quality filter media designed for use with abrasive dusts

Maintenance Reduction
Industrial dust collectors used in seed conditioning applications should have features to help reduce maintenance and enable changing of the collection bins without shutting down the unit. Look for:

• Vertical filter design and an advanced filter pulsing system to enable efficient shedding of excess dust from the filters to extend filter life.
• Flexible discharge options, including options for multiple drums or bins or connection to a conveyor system for collection and removal of dust.
• Rotary valves between the hopper and collection bin that enable bin changing without shutting down the unit.
• A bin sensor system, which can be added to the collection bin to monitor dust levels and provide an alert when the bin needs to be changed.

• Combustion risk: Combustion is the biggest risk faced by the seed processing Many of the dusts created during seed separation, processing and conditioning are highly combustible. That means they can generate an explosion when allowed to concentrate enclosed areas such as a grain silo, bin or conveyor system. In fact, most grain dusts are considered to be highly combustible. Special care must be taken when collecting combustible seed conditioning dusts to minimize the risks of an explosion inside the dust collector.
• Abrasion: Dust produced by some seed processing activities (especially pre-cleaning, destoning, etc.) is abrasive and may include materials such as small stones and other debris. Abrasive dust creates a lot of wear and tear on dust collection equipment and filters.
• Microbial growth: Seed and grain dusts create an ideal breeding ground for many different kinds of microbes, including yeasts, molds and bacteria. Many dangerous molds thrive on grain products such as corn and wheat. Dust control is important to reduce the spread of microbial pathogens through the seed separation and processing supply chain. Uncontrolled dust on surfaces can become a breeding ground for dangerous yeasts, molds and bacteria. If this dust is allowed to re-contaminate seed processing lines, pathogens can end up in the final product.
• Health and safety hazards: Heavy dust created by seed separation and processing operations can cause lung irritation or trigger asthma or allergies if inhaled. Uncontrolled dust of any type is also a housekeeping and sanitation consideration. While dust exposure may be less of a problem for processes that are conducted in open-air environments or by primarily robotic processes, it is still important to keep fugitive seed and grain dust away from areas where it can be inhaled. Dust created during seed coating (filming, pelleting or encrusting) or while moving and transporting coated seeds may be hazardous or toxic when inhaled. Seeds may be coated with fertilizer, pesticides (such as neonicotinoids), fungicides (e.g., “red dust”/Captan/Metalaxyl Thiram), micronutrients, biostimulants or microbial coatings that promote plant growth. Seed pelleting and seed encrusting are used to create a protective shell around the seed and increase size, weight and uniformity for easier planting. Inhaling pesticides, fungicides and fertilizers may cause acute respiratory distress and long-term health impacts. Workers exposed to fertilizer dust are at higher risk of lung cancer and emphysema. “Red dust” fungicides have been linked to neurotoxic and developmental impacts.
• Environmental concerns: “Dust off” of coating materials such as red dust from treated seeds may also pose an environmental concern. Fugitive pesticide dusts, especially neonicotinoids, become an environmental problem when allowed to escape into the atmosphere. Fugitive neonicotinoids in the environment have been implicated as a possible cause of large die-offs of wild bee colonies in recent years. Fungicides and pesticides also have detrimental environmental impacts when they wind up in aquatic ecosystems. Other impacts on the environment have not been fully studied. It is best practice in the seed coating industry to minimize the release of fugitive red dust and other coating dusts into the environment.