Publisher Summary This chapter highlights the need for interfaces and standards through the description of the activities during the conceptual design stage of the process design lifecycle involving the design of two processes by reviewing two case studies. The case studies point out the work-flow and data-flow associated with the solving of the conceptual design problems related to these case studies. The need for standard interfaces when solving practical design problems is provided. The first process involves conceptual design for the production of methyl acetate while the second process involves the production of polyamide-6. Both case studies employ a number of commercial software as well as software developed in-house. Methyl Acetate study emphasizes on the use of many smaller specialized tools in specific parts of the conceptual design and detailed engineering phase, whereas the Polyamide6 study describes the overall workflow in the conceptual design phase and focuses on the use of larger more generalized tools. Process design involves the application of different design approaches that require different methods and tools. Tools for analysis tools are used for evaluation of the chemical process of interest or parts of it under different scenarios, such as physical-chemical behavior, safety, environmental, or economic consideration.