Installed in hundreds of grain elevators, soybean and oilseed processing plants, seed production plants, flour mills, corn milling, animal feed and ethanol plants worldwide; Donaldson® Torit® collectors remain the most widely used collectors in the grain handling and processing industries.
Since its introduction in 2008, more than 300 Donaldson Torit® PowerCore® CP collectors have been installed in grain handling and processing facilities worldwide and are quickly becoming the new industry standard for grain dust control.
Torit cartridge style dust collectors (DFO and DFT) in the seed-treatment industry and Dalamatic® collectors in milling and oilseed processing industries illustrate just some of the versatile collectors available from Donaldson to meet the dust collection needs of the grain and agriculture industries.
Dura-Life™ bags are another example of Donaldson innovation, offering exceptional filter efficiency with lower pressure drop, delivering superior performance and lower operating costs. Additionally, Dura-Life filters capture dust on their surface where it is readily pulsed from the media, cleaning more effectively so filters last longer than conventional polyester bags in grain, seed and milling applications.
Introduced in 2009, the Airflow Controller optimizes fan energy consumption and extends filter life. When coupled with premium efficiency motors and variable frequency drives (VFD’s), the airflow controller can control fan speed to maintain static pressure at a point in the duct. By eliminating energy waste the Airflow Controller reduces energy costs and by modulating airflow the Airflow Controller prevents over-utilization of filter media, extending filter service life. Be sure to consult your energy provider PRIOR to moving forward with the purchase of premium efficiency motors, VFD’s and Airflow Controllers, as many energy suppliers offer rebates and incentives that require pre-approval.
Processes Involving Grain Dust
Most grain dust is created by material handling processes, which include:
| Dump pits |
Break milling |
Sifters / Sorters / Classifiers |
|---|
| Elevator legs |
Bin / Silo loading |
Roller milling |
|---|
| Conveyors |
Packaging |
Barge / Rail car / Truck loading |
|---|
| Garner scales |
Drying |
Mixing bin venting |
|---|
| Grain cleaners |
Hammer milling |
|
|---|
The following diagrams show typical material handling and processing steps involving grain.
Major Process Operations at a Grain Elevator (source: EPA AP42 Emission Factors)
Simplified Process Flow Diagram of a typical Flour Mill
Flow Diagram for Oat Processing Operations
Flow Diagram for Conventional and Parboil Rice Mills
Simplified Process Flow Diagram for a
Corn Dry Milling Operation with Degerming
Typical Animal Feed Milling Process Flow Diagram
Special considerations for grain dust
When grain reaches an export terminal it has been handled between 5 and 10 times. As a result, dust loading may be higher andhtis should be taken into consideraiton when sizing collectors.
Cartridge style collectors are typically suitable for seed production plants because seeds are handled more gently than common grain and therefore, emit less dust.
Oilseed processing often involves both heat and oils so be sure to consider both when selecting dust collectors.
Health and Safety Considerations
Grain dust can be highly combustible so an understanding of NFPA, OSHA, and EPA regulations is often required. Typically any collector may require an explosion mitigation strategy such as explosion vents or chemical suppression systems.
LEGISLATION (OTHER FEDERAL AND LOCAL LEGISLATION MAY APPLY)
US EPA
Particulate Matter (PM):
- 40 CFR 60.300 Subpart DD - Standards of Performance for Grain Elevators - No more than 0.023 g/m3
- PM 2.5 = 15 µg/m3 (annual), and 35 µg/m3 (24-hour)
- PM 10 = 150 µg/m3 (24-hour)
OSHA Regulations
- 29 CFR 1910.1000 - Air Contaminants
NOTE: Twenty-five states, Puerto Rico and the Virgin Islands have OSHA-approved State Plans and have adopted their own standards and enforcement policies. For the most part, these States adopt standards that are identical to Federal OSHA. However, some States have adopted different standards applicable to this industry or may have different enforcement policies.
- 29 CFR 1910.272: Grain handling facilities
- 29 CFR 1910.1000 - Z1: Grain dust (oat, wheat, barley) PEL = 10 mg/m3
REFERENCES
Industrial Ventilation Manual
NIOSH Publication No. 76-179
WAC 296-818-500
AP-42, Compilation of Air Pollutant Emission Factors, Chapter 9