Verification of structures for utilization of waste multicomponent electrolytic systems

Determination of process structure of thermal utilization of mineral mat­ters from waste streams, is a multi-variant problem. These processes are energy-intensive and it is very important to determine the process structures for realization of the required processes in the starting phases of process development. The structure of the process system, beside the system equilibrium, depends on vector parameters of the feed stream. In this work a newly developed methodology for determination of process variants of thermal utilization of mineral salts from a hypothetical three-component AX-BX-H2O system is presented. The methodology is created on starting synthesis problem for which a set of types of process units for realization process and type of desired crystal product is determined. The methodology includes process decomposition in two subsystems: concentration (saturation) subsystem and crystallization subsystem. Concentration of feed stream is realized in isothermal conditions of water evaporation and crystallization process using various techniques: isothermal water evaporation, cooling of solution in vacuum and cooling of solution through contact surface. Determination of physical feasible processes is performed by simulation of the process superstructure in which each particular process structure is a special case of the created process superstructure. Realization of mentioned activity is provided by creating algorithms and programming software (process simulator) in which the equation system of the superstructure mathematical model is solved for various variants of set of specified variables. The created methodology and possibilities of the created process simulator are presented in the illustrative case study of waste stream utilization of the NaCl-KCl-H2O system. In addition to this, for conditions of total heat integration of subsystems is demonstrated that a small change of salt concentration of feed stream can require transfer non-cyclic in cyclic process structure.