Intensification of the Grain Drying Process with an Ozone-Air Mixture

Abstract

Background: The use of ozone allows not only to weaken the connection of moisture with the grain, but also, interacting with its internal components, the gas contributes to an increase in the temperature of the heap. Due to this, the grain must be heated for less time before reaching optimal parameters, which reduces the energy intensity of the drying process. At the same time, the separation of moisture from the grain occurs more intensively, since the gas in small concentrations improves the permeability of cell membranes, causes structural transformations of the integumentary tissues and promotes the orientation of water molecules around atomic oxygen. As a result, the drying time is significantly reduced. After treatment, the residual ozone decays to oxygen without polluting the environment. In addition, ozonation promotes deodorization, sanitation, sterilization of grain and equipment. However, the use of ozone-air mixture in grain drying in production is too insignificant due to the small experimental base and lack of practical recommendations. Purpose: Improving the efficiency of modern grain dryers through the use of the ozonation process. Materials and Мethods: The theoretical and methodological basis of the research was the work in the field of grain drying with an ozone-air mixture by leading Russian and foreign scientists, as well as their own research. The sources under study cover the first mentions of the use of ozone in grain drying and the subsequent development of this topic. The review included publications from various databases, among which are: e-library, Scopus, Web of Science, Agris, FIPS and others. Results: Hourly preliminary ozonation of grain with a humidity of 26.3% contributed to a decrease in the moisture content by 1.3% from the initial value. While in the control sample, which was not subjected to preliminary ozone treatment, the moisture content did not change over the same period. Subsequent drying of the exposed grain allowed for an hour of operation to remove 1.6% more moisture than that of the control sample. At the same time, the drying conditions of both batches of grain were identical. This indicates that the ventilation of grain with an ozone-air mixture is more effective than its presence in a buffer silo without processing. Conclusion: Pretreatment of a wet grain heap with an ozone-air mixture before feeding it to the grain dryer intensifies the process of subsequent grain drying. At the initial grain moisture content of 26.3%, hourly ozone treatment with an ozone concentration in an ozone-air mixture of 8 mg/m3 reduces the moisture content by 5.4% per hour of drying. Under the same conditions, in the experiment without processing for the same period, the decrease in grain moisture was 3.8%. Consequently, the proposed method of grain drying increases the efficiency of modern grain dryers.