QUALITY CHANGES, DUST GENERATION, AND COMMINGLING ...

Abstract
The United States grain handling infrastructure is facing major challenges to meet
worldwide customer demands for wholesome, quality, and safe grains and oilseeds for food and
feed. Several challenges are maintaining grain quality during handling; reducing dust emissions
for safety and health issues; growing shift from commodity-based to specialty (trait-specific)
markets; proliferation of genetically modified crops for food, feed, fuel, pharmaceutical, and
industrial uses; and threats from biological and chemical attacks. This study was conducted to
characterize the quality of grain and feed during bucket elevator handling to meet customer
demand for high quality and safe products. Specific objectives were to (1) determine the effect of
repeated handling on the quality of feed pellets and corn; (2) characterize the dust generated
during corn and wheat handling; (3) develop and evaluate particle models for simulating the flow
of grain during elevator handling; and (4) accurately simulate grain commingling in elevator
boots with discrete element method (DEM).
Experiments were conducted at the research elevator of the USDA-ARS Center for Grain
and Animal Health Research (CGAHR) to determine the effect of repeated handling on the
quality of corn-based feed pellets and corn. Repeated handling did not significantly influence
the durability indices of feed pellets and corn. The feed pellets, however, had significantly
greater breakage (3.83% per transfer) than the corn (0.382% per transfer). The mass of
particulate matter < 125 µm was less for feed pellets than for corn. These corn-based feed pellets
can be an alternative to corn in view of their handling characteristics.
Another series of experiments was conducted in the same elevator to characterize the dust
generated during corn and wheat handling. Dust samples were collected from the lower and
upper ducts upstream of the cyclones in the elevator. Handling corn produced more than twice as
much total dust than handling wheat (185 g/t vs. 64.6 g/t). Analysis of dust samples with a laser
diffraction analyzer showed that the corn samples produced smaller dust particles, and a greater
proportion of small particles, than the wheat samples.
Published data on material and interaction properties of selected grains and oilseeds that
are relevant to DEM modeling were reviewed. Using these material and interaction properties
and soybeans as the test material, the DEM fundamentals were validated by modeling the flow of