Economical sustainability of multiphase systems

In this book chapter, economical sustainability of liquid–liquid separation will be discussed. Economic feasibility is one of the most important aspects when it comes to process flow on an operating a separation system. Various types of interactions for separation process will be evaluated, which includes polymer–polymer interaction, polymer–salt interactions, alcohol–salt interactions, sugar–solvent interactions, ionic liquid–salt interactions, and t-butanol–salt three-phase interactions will be evaluated. The economical sustainability and mechanism of each of the interaction are similar which only alters the materials used and is mostly aqueous two-phase separation process. To assess the economic feasibility, first the costs and benefits have to be analyzed with each interaction. The capital cost of a project greatly affects the economic evaluation. Cost estimation is a process that can estimate the outcome of a future capital expenditure. The operating, maintenance, and equipment cost will be evaluated in terms of costing for all different interactions. Costs for each interaction were estimated based on case study made or currently running process that is similar to the interaction being analyzed. Besides that, two different economic evaluation methods that are used to assess the investment are net present value and internal rate of return. Time value of money must first be understood to calculate net present value and internal rate of return because a dollar today can be invested and gain a return in the future. Lastly, break–even analysis will be discussed in the economic section for each interaction. Break–even analysis is a useful cost–benefit analysis that can identify the point that benefits are equal to costs. This analysis can determine whether the process is making a profit or having a loss and it also expresses a minimum revenue target.