Visual basic computer package for thermal and membrane desalination processes

A visual basic computer package was developed for the design and analysis of thermal and membrane desalination processes. The package includes conventional processes, i.e., reverse osmosis, single-effect mechanical vapor compression, multiple-effect evaporation with/without thermal or mechanical vapor compression, and multi-stage flash evaporation. The models for these systems provide detailed design data that include flow rates, stream salinity, temperatures, heat transfer or membrane area, ejector dimensions, and bundle dimensions. The model predictions are based on detailed energy and material balances and well tested correlations for the heat transfer coefficient, thermodynamic losses, and physical properties of the seawater and water vapor. The visual basic interface provides displays for profiles of system variables across the effects, stages, or membrane modules, which may include salinity, flow rates, etc. Also, displays for the process flow diagram and design results are generated simultaneously. The design results include the unit product cost, process capital, performance ratio or specific power consumption, the flow rate of cooling water, the heat transfer or the membrane area, and a number of thermodynamic losses.

This paper summarizes the developments in the visual basic simulation package of thermal and membrane desalination processes. Several additions have been made in the packages including cost estimation, simulation of the RO process, calculations of effect dimensions, and a detailed design of the steam jet ejector for vapor com- pression. The development process was necessary to improve the capabilities of the simulator. The simulator proved to be highly useful in teaching desalination and engineering training. The simulator gives the user efficient tools for system design or simulation. Results give the user the means to have a better understanding of the desalination systems. Further modification and additions are underway, which are based on feedback of users in other colleges and the industry. The package integrates well with other literature attempts focusing on developing a package for process simulation or cost estimation.