Computer Modeling of the Dynamics of Energy Consumption during Expanded Clay Burning

High-strength expanded clay is widely used in the construction industry for the construction of high-rise buildings, bridges and stressed reinforced structures, the construction of roads and airfield pavements, and in the construction of oil platforms. The use of expanded clay as a filler makes it possible to reduce the weight of structures, to increase their frost resistance and durability. The manufacturing of high-strength structural expanded clay is a complex, time-consuming and energy-intensive process. The share of fuel costs makes up for about a third of the cost of the finished product. Therefore, one of the main indicators that determine the economic efficiency of expanded clay manufacturing, in addition to productivity, is the ratio of volumetric fuel consumption to the volume of 1 m³ of expanded clay being manufactured. It is possible to carry out energy-efficient manufacturing of expanded clay by automatically adjusting the expanded clay burning curve with a multidimensional automatic control system for the rotational speed of the kiln, the amount of expanded clay raw material loaded into the kiln, and the volumetric thermal power of the burner. This approach eliminates the operator-specific errors occurring in the «manual» burning control mode based on heuristic algorithms, and thereby ensures rational fuel consumption. In this paper, we consider a generalized process control structure for burning expanded clay in a rotary kiln, focused on modeling both «manual» and automatic kiln control. The created model allows one to track the dynamics of fuel costs for the manufacture of 1 m³ expanded clay of various grades of strength. The authors present the technique of determining the coordinates of the operating points in the three-dimensional space of the output coordinates of the control object OTFTATC of the temperature-strength characteristic, which provides predicting the strength of the expanded clay obtained during automatic burning control. The technique has been developed for setting up numerical modeling of rational expanded clay burning curves aimed at minimizing the energy consumption. Comparison of fuel consumption for «manual» and automatic control of the burning process is carried out.