Date of Graduation

5-2018

Document Type

Thesis

Degree Name

Bachelor of Science in Biological Engineering

Degree Level

Undergraduate

Department

Biological and Agricultural Engineering

Advisor/Mentor

Osborn, G. Scott

Committee Member/Reader

Atungulu, Griffiths

Committee Member/Second Reader

Liang, Yi

Abstract

In-bin grain drying reduces the moisture content of field harvested grain down to a level suitable for profitable storage. The traditional method for in-bin deep bed grain drying is conducted in a cylindrical grain bin with an approximate height to diameter aspect ratio of 1:2, a stirring mechanism, a bottom plenum, a fan, and a heating element. This method poses problems by having a drying front that can move through the grain bed too slowly causing over or under drying leading to losses. This method also requires a stirring mechanism with significant capital costs and the inability to use sensing cables to monitor and control the drying process. This thesis proposes a new system that eliminates the need for a stirring mechanism, decreases the drying front phenomena, decreases drying duration, and decreasing operating costs. An EXCEL model was created using equations for pressure loss, moisture content, equilibrium relative humidity, and psychrometric properties to estimate the function of a 3 ft tall by 4 ft diameter bin. A prototype was constructed and experiments for both the traditional and proposed system were conducted to validate the model’s implications. Starting at a moisture content of 14% wet basis, soybeans were dried to 7% wet basis. The data from the experiment showed the traditional system dried as the model predicted, and some data from the proposed system showed a faster drying rate than the traditional system. There was suspected error in sampling moisture content and determining the amount of wetting of the soybeans and further testing should be conducted to confirm this observation. The model predicted a 9 hour faster drying duration for the proposed system with the same fan and drying air temperature. The model was scaled up to an industrial size grain bin of 20 ft tall by 27 ft diameter, and for the proposed system, it calculated a drying duration that was 24% or 1.4 days shorter and a reduction in operating costs by 22.7% saving $417.43 in the proposed system compared to the traditional system. This model and experiments indicate that further testing should be conducted to determine if the proposed method could be a suitable alternative for traditional in-bin, deep bed grain drying.

Keywords

grain drying; food processing; energy savings; agriculture

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