DWSIM is a chemical process simulator. It is based on the concept of a chemical reaction, which is the basis of all transformations in nature. This concept is used to describe the flow of matter and energy in a chemical system, from the production of substances in the Earth's atmosphere to the chemical reactions that take place in the depths of the Earth's oceans. 

The main objective of the software is to find the most stable operating point of a given process, in order to predict the behavior of a real-world process. This is achieved by solving the mass and energy balance, using a specific solver algorithm. The algorithm is based on the idea of a linear-programming method, which is one of the most effective methods for solving nonlinear equations.