Process for improving thermal efficiency while producing power and desalinating water

摘要

A process and apparatus for improving the thermal efficiency of a steam turbine power generating plant while simultaneously desalinating seawater or brine and purifying water which contains minerals, salts, and other dissolved solids. Exhaust gases from a power plant is heat exchanged against water in a secondary ecomomizer which circulates water at a temperature near, or slightly above the dewpoint of the combustion exhaust of the high-pressure boiler. The heated water is flashed to produce low-pressure steam. The low-pressure steam is condensed against the last effect of a multi-effect desalinization unit. Steam from the first effect of the desalination unit is condensed against steam condensate from the power plant turbine to preheat the condensate and thereby recover heat from the power plant's exhaust gas. Salinous water is fed to the multi-effect desalinization unit to produce fresh water and a concentrated brine. The low-pressure steam is used to replace high-pressure steam that is used for preheating and deareation of feedwater for the boiler.