Abstract
When we design a new plant or plan a production schedule, simulation is the most practical technique to forecast and evaluate the plant operation. The chemical processes in a plant with control systems are represented by a set of differential equations and algebraic equations. Continuous simulation can solve these equations. However, the plant is usually controlled by the sequential control system, and is sometimes operated by the human operators in the discrete event mode. These facts require a combined discrete-event and continuous-process simulation. In this paper, we developed a new simulation method which more properly fulfills the functions necessary to simulate the combined discrete-events and continuous-processes. In the method, the target process is modeled by three types of elements, i.e., continuous-process, discrete-event, and sequential control. Since sequential control has the intermediate characteristics between discrete-event and continuous-process, it is more convenient for modeling to handle it as the third element. The simulation program can provide a powerful tool to simulate the complex systems such as a combined batch and continuous process, a pipeless batch plant, a textile mill and so on.
