Abstract
In the chapter, both informational and system-based approaches have been applied to the analysis of grain drying process as an interaction of two systems, namely, “drying agent” and “grain layer.” It made it possible to evaluate the information content of the process. Analytic expression has been obtained for grain layer informational entropy variations which enabled to make the conclusion that an adequate physical description of grain drying process has to include ambient air parameters control, as well as that of drying agent's parameters in its exit out of a grain layer, as well as parameters of both drying agent and grain in one point of grain layer. A mathematical model of heat-and-moisture exchange in dense grain layer has to be applied. As a result of modeling, it has been proved that the sensors of both drying agent and grain parameters have to be located at a distance of 10 to 11 cm from the central cylinder of the forced-aerated drying bin.
TopIntroduction
Grain drying by forced aeration is a process of long continuance in which ambient air is used as a drying agent (Vanckul, Goryacheva, Garyaev & Sorochinskij, 2017 (Onhonova & Skryabina, 2017; Sabiev & Shonov, 2017; Vasilyev, 2008). Air is heated only in case that its relative humidity exceeds 70%. Air is normally heated with the use of electric fan heater. Drying ability of ambient air is not high. That is why it becomes wet soon while blowing through a grain layer. Grain layers located in the input of the air flux get dry faster. Within the day period, temperature and humidity of ambient air may change in a wide range. Therefore, a substantial irregularity of thick grain layer drying process may occur. Those grain layers that air enters first may appear overdryed. At the same time, grain layers located in the output of the air flux may absorb moisture (Vasilyev, Budnikov, Gracheva & Severinov, 2016; Filatov & Paulys, 2017; Lauva, Aboltins, Palabinskis & Karpova-Sadigova, 2006; Petraq & Francois, 2015).
In homogeneity in grain drying can be reduced and the productivity of drying process can be enhanced owing to the improvement of process control. It was suggested to control both fan performance and capacity of electric heating elements (Gulyaev, 1990; Mashukov & Safonov, 2017). It has to be done with the account of specifics of grain layer moisture content distribution in the bulk of layer. What has to be the set of drying agent and grain layer parameters under control that will provide the necessary and sufficient conditions of effective drying process? Certain studies have to be performed to answer this question. In these studies, it is essentially important to evaluate informational content of heat-and-moisture exchange process in grain layers. Therefore, informational contents for both drying agent and grain layer have to be first separately estimated and, only after that, it is possible to evaluate that of their interaction process.
Key Terms in this Chapter
Active Ventilation: Blowing atmospheric air through a grain layer.
Process Informativeness: The amount of information that control means receive when measuring process parameters.
Active Ventilation Bunker: A vertically located cylindrical container, which is filled with grain. In the center of the tank there is an air duct through which air is fed into the grain layer.
Mathematical Model: Mathematical description of the relationship between process parameters.