What methods are used for process optimization in design?

Process optimization methods: Parametric studies - vary one parameter to find optimum (e.g., reflux ratio vs. stages). Design of experiments (DOE) - systematic exploration of multiple variables. Pinch analysis - optimize heat integration. Economic optimization - minimize total cost (CAPEX + OPEX present value). Mathematical optimization - use simulation optimizer with objective function (e.g., minimize steam consumption subject to product spec). Common optimization variables: operating pressures, reflux ratios, reaction temperatures, recycle ratios. Constraints: product specifications, equipment limits, safety requirements. Tools: Excel solver, Aspen optimizer, GAMS for complex models. Always verify optimum is robust to parameter uncertainties.