Design of Solids Processes: Production of Potash

Various issues encountered in the design of solids processes are examined through the analysis of a concrete example the production of potash.Economic trade-offs from a systemspoint of view are identified, and the sensitivity of the total process cost to each key design variable is quantified. It is shown that the dissolver and crystallizer temperatures cannot be set at the optimum conditions unless pressurization and refrigeration are employed at the respective units. The economic impact of the degree of saturation in thedissolver is found to be significant, because of its coupling to the recycle flow. Furthermore, the sensitivity of the total processcost to the uncertainty in various model parameters is evaluated. In addition to the potential benefits to the design and operation of a potash plant, this study serves as the first step in the development of a comprehensive hierarchical procedure for the design of solids processes.