Automated Decision Support System in the Energy- and Resource-Efficiency Management of a Chemical-Energy Engineering System for Roasting Phosphorite Pellets

Mathematical and computer-based models of a complex chemical-engineering roasting process as an interdependent plurality of three processes—drying, calcining, and sintering of moving, tight, and multilayered mass of phosphorite pellets in conveyer roasting machine, differing in attention to the intensity of processes of internal moisture transfer within the pellet and overwetting processes of separate horizons in heated pellet layer, have been developed, making it possible to the determine engineering parameters of the roasting mode. The adequacy of the mathematical model is checked from the comparative analysis data of calculated values of the moisture content and the temperature of pellets and parameters of heat-transfer gas, as well as moisture-transfer intensity in pellets when they are dried in the moving tight layer, were compared with the data of industrial testing. Numerous calculated experiments to determine the relative extent of drying, the moisture content, the intensity of pellet drying, and the moisture content of heat-transfer gas are carried out, in which crude pellets and the engineering data of the operating mode of a roasting machine have different parameters. An informal and mathematical statement of the problem of optimizing the chemical-energy engineering process (CEEP) for roasting the moving tight multilayered mass of phosphorite pellets within the complex chemical-energy engineering system (CEES) of the conveyer roasting machine is developed as the problem of discrete dynamic programming in light of spatiotemporal multistage processes for roasting the moving multilayered pellet mass, the intensity of the internal moisture transfer processes within the pellet, processes of overwetting the separate layers of pellets, and variables of the control stream of the heat-transfer gas; this makes it possible to enhance energy efficiency by means of intensifying heat-and-mass transfer processes of multilayered drying, calcining, and sintering. The performance criterion is the minimum cost of electrical and heat energy expended on the CEEP for roasting. The results were used to calculate energy efficient pellet roasting in CEES of the conveyer roasting machine. It has been found that, under the optimum mode of multilayered pellet roasting, there is no overwetting zone, processes of heat and moisture transfer are intensified, energy consumption decreases, and the quality of the end product increases. The problem of pellet overwetting in separate layer horizons of the drying zone of the roasting machine has been studied. The actual theoretical and practical problem of energy and resource saving in roasting pelletized crude ore in the tight layer has been solved. The mathematical model of heat-mass exchange in the pellet layer and testing its adequacy have been presented. The problem of optimizing power inputs based on the intensification of roasting processes has been solved.