Grain Storage: Considerations to Maintain Quality: Part 4 - Aeration Problems And Solutions

Aeration Problems And Solutions

1. Aeration Problems - A common problem that can occur during aeration is a front that stops. If someone stops the aeration fan midway through the aeration process, the moisture and heatladen front will stall. When the front stalls, it despots the carried moisture and heat in the grain. When aeration is started the second time, the front will again begin at the bottom of the bin, while the heat and moisture deposited above begin to spoil the grain. If the new front does not reach the old front in time spoilage in the old front will create a crust that prevents the movement of air, preventing any additional aeration. The grain must be removed from the storage structure.

Aeration Solution - After beginning an aeration cycle, do not stop the aeration fan(s) initial the aeration cycle is completed.

2. Aeration Problem - Center Fines or Foreign Material (FM). FM is anything that is not whole grain. FM can be broken grain, other organic parts of the grain plant, or weed seeds. Generally, FM has less weight than whole grain. While filling the grain storage structure, the FM will fall into the center of the structure and the heavy good grain will roll or slide to the outside of the structure. The FM in the center of the storage structure can form a column through which air will not pass. This column will spoil very quickly, spreading to the good grain. When the storage structure is unloaded through the bottom, the column will prevent grain from flowing out.

Aeration Solution #1 During and after filling the storage structure, you should remove a portion of the grain. This will extract the centre core. The extracted grain can be processed by cleaning, or by grinding immediately for feed.

Aeration Solution #2 During filling, you can use a mechanical spreader to distribute the FM in a wider area, preventing the buildup of a centre core. The FM will remain in the grain, and can continue to contribute to premature spoilage of the grain.

Aeration Solution #3 Clean the grain before filling the storage structure. This requires a mechanical cleaner or mechanical screener that will separate good, whole grain from any form of FM. This is the best solution for long-term storage. Whole grain stores much better than FM, and permits easier aeration of better quality.

3. Aeration Problem An obstructed aeration air delivery system will prevent good aeration. Even with the fan running, air cannot pass a dirty obstructed tunnel or perforated floor. Vents that are plugged will prevent air from exiting the storage structure, stopping all aeration.

Aeration Solution Before filling the storage structure, inspect in the tunnels under the aeration floor for an accumulation of broken, spoiled grains that obstruct air movement in the tunnels. If necessary, clean and remove all FM. This will also remove insects, insect eggs, and their habitat. Also inspect roof vents for any obstructions, and clean if necessary.

4. Aeration Problem Over filling the storage structure, and grain too close to the roof or touching the roof. When too much grain is put into a storage structure, two problems are created. 1) Not enough space remains for the movement of air to the exhaust vents during aeration; 2) Grain comes in contact with the roof, where condensation can occur. Condensed moisture will collect at the edge of the roof, and saturate the outside of the grain mass. Spoilage will occur in this area

Aeration Solution Do not overfill the storage structure.

5. Aeration Problems Examples of aeration problems. This storage structure has been over filled. Grain has blown out of the vent onto the roof of the silo and spoiled; grain remains stuck in the vent and is obstructing airflow; grain has spoiled and stuck to the walls of the storage structure. The spoiled grain will be difficult to remove, and can affect the new grain when the storage structure is filled again.