*Corresponding author: Salah Frioui Laboratoire d’Analyses Industrielles et Génie des Matériaux (LAIGM), Université 8 Mai 1945 GUELMA, B.P.401, 24000, Algérie ISSN: 0976-3031 Research Article MODELISATION AND SIMULATION OF DESALTING PROCESS: A CASE STUDY Salah Frioui Laboratoire d’Analyses Industrielles et Génie des Matériaux (LAIGM), Université 8 Mai 1945 GUELMA, B.P.401, 24000, Algérie DOI: http://dx.doi.org/10.24327/ijrsr.2020.1107.5458 ARTICLE INFO ABSTRACT This paper presents a mathematical design model for calculations of the physical and thermodynamic properties of the vapor and liquid streams, heat transfer coefficients, taking into consideration the nonlinearity of the thermo-physical properties of seawater and steam.Realistic assumptions and where semi-empirical and empirical equations are incorporated into the calculations will make the model practical and rigorous. Then a computer program, named FLASH, was developed to simulate the operation of this process. In order to validate the FLASH program, a comparison was made between the obtained results performed by FLASH forOSW Company of Philadelphiawith the results of the same company with the same input data. Once the comparison made and good agreement is obtained, then the programFLASH was performed for the plant of desalination in the complex of Skikda. From results obtained, it is obvious that the simulated program performs well. From this study, the program proved to be able to converge reasonably quickly and the direct substitution approach of solution proved to be successful for already existing plant process or new one! INTRODUCTION The rapid growth of the different fields in industry created opportunities for new computer program languages. Computer simulations have become a useful part of mathematical modeling of many natural systems in physics, chemistry, and biology, human systems in economics, psychology, and social science and in the process of engineering new technology, to gain insight into the operation of those systems. The overall modeling approach was used to perform a mass and energy balances of the thermal desalting process, heat transfer equations, physical properties correlations and the temperature losses due to boiling point variation. And then, we can establish a simulation program to estimate rigorously the different parameters and physicals properties of the system. For a given design, optimisation of operating variables led to an increase in distillate production rates and lower operating costs [1, 2, 3, 4, 5, 6, 7, 8]. Traditionally, the formal modeling of systems has been via a mathematical model, which attempts to find analytical solutions to problems which enable the prediction of the behavior of the system from a set of parameters (top brine temperature, brine recirculation rate, intake flow rate, steam conditions and flow rates). In addition, the selection of optimum design and operation of MSF desalination plant is aimed at reducing energy and operation costs such as, n major cases, steam, electric power, anti-scale. As it is reported in literature, the main features of the MSF plant include variable capacity, slow dynamics, dead-time characteristics due to certain load changes, significant effects of small deviations from design conditions on plant operation, effects of power plant output conditions on the desalination plant, instability due to disturbances in steam supply, and water temperature variations. All studies show some disturbances, which may include feed seawater temperature, intake seawater temperature, feed seawater flow rate, pressure, flow rate, pH, concentration, brine and distillate levels in the last stage, brine heater condensate level and the top brine temperature. These developments were not fundamentally novel, rather they were refinements to existing models and practices, and largely based on the experience and observations programming languages. There have been interesting researches in modelisation and simulation, optimisation and control in terms of parametric analysis, thermo-economic and thermodynamic optimization towards the improvement of thermal desalination processes. Important research activities have been devoted to solve this problematic. So, many models have been developped to find a functional relationship between the design and operating variables [7]. Modeling of the MSF process dates back to the Available Online at http://www.recentscientific.com International Journal of Recent Scientific Research International Journal of Recent Scientific Research Vol. 11, Issue, 07 (B), pp. 39192-39206, July, 2020 Copyright © Salah Frioui,, 2020, this is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. DOI: 10.24327/IJRSR CODEN: IJRSFP (USA) Article History: Received 6 th April, 2020 Received in revised form 15 th May, 2020 Accepted 12 th June, 2020 Published online 28 th July, 2020 Key Words: Simulation and optimization, mathematical model, operating conditions,algorithm;,MSF desalination plant.