Regression mathematical model of two-stage combined electrical technology of high-temperature convective drying and ozone-air grain processing

Abstract

Large production of cereal crops in Russia in 2014-2018 (100-130 million tons) imply the need to dry 10-30 % of the crop collected annually in the country to ensure its quantitative and qualitative preser-vation. The main way to reduce the excess moisture of grain in the Russian Federation is high-temperature convective drying, but it refers to very energy-intensive technological operations and, therefore, is very expensive. In the context of the constant increase in energy prices in the Russian economy, the country's agricultural producers face the primary task of increasing the profitability of the grain industry, within which it is necessary to reduce material costs at all stages of production, including through the creation of new high-intensity energy-saving technologies and technical means for drying grain raw materials. The authors have developed a two-stage technology of high-temperature convective and ozone-air grain drying that meets these requirements. In the article, based on the analysis of the parametric scheme of the convective-ozone-air moisture removal method, compiled taking into account the conditions and possibilities of conducting experimental studies of the process at the industrial drying unit «ELEKTA-1» of small productivity, the optimization parameters of this process are defined, which are: reduction of the drying time and the total reduction in energy consumption, in addition, the main factors varied in the ex-periments are highlighted: the initial moisture content of the grain, the amount of ozone supply to 1 m3 of grain and time spent on moisture removal. Second-order regression mathematical models for the convec-tive-ozone-air drying of barley grain with different initial humidity (30, 25 and 20 %) have been developed and their statistical significance has been evaluated. An analysis of the experimental data of the combined drying options studied at 6 % moisture removal for one cycle of processing the grain material revealed the following parameters of the efficiency of the methods of convective ozone-air moisture removal: when drying grain with an initial humidity of 30 %, the process duration decreased by 28 % and the total energy consumption decreased amounted to 33-43 %; when drying grain with a moisture content of 25 %, the duration of the process is reduced by 19 %, energy consumption by 24-35 %; and when drying grain with a moisture content of 20 %, the duration of the process is reduced by 30-35 %, energy consumption by 35-40 %.