Studies of Evaporative Efficiency by Dynamic Simulation of an Open Integrated Industrial System

The aim of this study is to perform a dynamic modelling and simulation of a Portuguese industrial integrated system in order to analyse the integration and feasibility of the different units, maximizing its efficiency and minimizing its environmental damage, and to study the effect of some operational and atmospheric conditions on the system. For this purpose it was built a dynamic model of the integrated system which includes the cogeneration system, the plate heat exchangers and the salt production unit. The cogeneration system was modelled and analysed using GateCycle 5.34.0.r software. It was concluded that the electric and the thermal power strongly depends on air and economizer cooling water temperatures. The distributed dynamic model developed of the whole integrated system was simulated and exploited through gPROMS 2.3.7 and gives the brine temperature, concentration and ponds level profiles as well as the thermal efficiency and the final salt production inside the recrystallization ponds, using different atmospheric and operational conditions as state variables. In this paper the best operational conditions necessary to maximize the ponds evaporative efficiency are exploited. It was studied the effect on the ponds evaporative efficiency of the ponds brine temperature and of the increase of the plate heat exchangers total area, using different atmospheric scenarios. The increase of the plate heat exchangers area will allow a more intensive use of two ponds at higher temperatures. This operational procedure will increase the ponds evaporative efficiency. Also an useful correlation was establish between a model calculated variable (x) and the operational hot brine recycled flow rate distribution in the working ponds.