For many plant building projects, the creation of a calculated process simulation is indispensable to verify that the intended process concept is physically possible. The process simulation can be done with a simple spreadsheet calculation or, depending on the complexity of the plant, with specialized software. Usually, the minium requirement is the availability of a database with the thermodynamic properties of the process media. The process simulation often serves as the basis for the sizing of the plant components. Furthermore, it is often used as a starting point to investigate possibilities to simplify the plant and to reduce the number of the required components, as well as to increase the plant capacity.