Simulation of the steady-state and dynamic behaviour of multiple effect evaporation plants Part 2: dynamic behaviour

Abstract A computer program for simulation of the dynamic behaviour of general multiple effect evaporation plants has been developed. The computer program, called DYNEFF, consists of a number of dynamic blocks comprising the necessary differential and algebraic equations for evaporator vessels, flash tanks, heat exchangers, etc., and an administrative part governing the input/output procedures, the solution procedures, etc. DYNEFF is used in combination with a previously presented computer program, called INDUNS, for calculation of all the necessary initial values. INDUNS performs a design or evaluation calculation of the desired multiple effect evaporation plant, and transfers the steady-state data as well as the flow sheet data to DYNEFF. Using the program combination, simulation of the dynamic behaviour of complete multiple effect evaporation plants is easily carried out. The main objective of the work is to increase the possibilities of achieving better knowledge and understanding of the dynamic behaviour of multiple effect evaporation plants. It should also be possible, to use the program combination to predict the dynamic behaviour of plants under construction as well as running plants, and thereby facilitate the determination of proper controller settings, suitable equipment sizes, etc.