FBA Issue 7: March / April 2006
Grain aeration: Problems and solutions
by Mark MYERS
THE primary objective of large capacity grain-storage silos is not for "holding" the grain but to preserve it in good usable condition for consumption. Spoilage losses of as little as 0.5 percent of stored grain can be a major financial drain.
One of the best tools for risk management of stored grain is ventilation, better known in the grain industry as aeration. Aeration is the process of moving relatively small volumes of air, under low pressure, through a grain mass. A well-designed aeration system involves a calculated volume of air (relative to the volume of the grain), calculation of the resistance to air flow through the grain mass, and properly designed fans, delivery systems, and vents to achieve optimum performance of the system.
To better understand the design parameters of a grain aeration system, it is necessary to answer the question: Why do we aerate grain? We aerate dry grain to maintain it in good storage condition. Aerated grain is more resistant to mould and fungal growth and has less insect activity. Aeration also controls the accumulations of moisture and heat.
It is important to understand that grain condition can never be improved--it can only be maintained. Grain that has high moisture content, or is broken and cracked, is more susceptible to mould, spoilage and attack by insects. Aeration cannot improve decayed grain but maintains the quality of grain that is already in good condition.
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