SIMULATION AND DATA VALIDATION IN MULTISTAGE FLASH DESALINATION PLANTS

This paper describes the main concepts of a specific Fortran program t ackling steady-state simulation and data validation (gross error detec tion and data reconciliation) for multistage flash desalination plants . The process simulation was carried out using an equation-oriented ap proach in which the decomposition of the system leads to a sensitivity matrix which is diagonal by blocks with extra diagonal blocks. The to pology of this matrix is conserved according to a procedure which can be extended to an unsteady-state simulation of the process, justifying the interest of the adopted methodology. The validation of the raw pr ocess data was achieved by the implementation of a simultaneous strate gy of gross error detection and data reconciliation, based on the biva riate method. In this approach we minimize an objective function using the maximum likelihood principle, which takes into account both contr ibutions from random and gross errors, The complete mathematical model describing the process behaviour at steady state was considered as co nstraints in the process optimization. Results corresponding to the st ructural and operating conditions of the distiller N degrees 5 of Umm Al Nar East plant which was put into service in 1987/1988 in the Emira te of Abu Dhabi are presented. This package was developed at the Schoo l of Chemical Engineers in Toulouse (France), and the project was spon sored by the International Centre for Water and Energy Systems (ICWES) located in Abu Dhabi (United Arabs Emirates).