Chemical process design is a multi-objective optimization problem with conflicting objectives. It can be solved efficiently by calculating the Pareto frontier, a set of Pareto-optimal compromises. This work describes how multi-objective optimization and decision support techniques have been implemented in the process simulation software CHEMASIM. The Pareto frontier is calculated automatically and an innovative slider concept is used to navigate the results and to support the decision making. With the help of two examples, the optimization of the process design workflow is demonstrated.