Energy transfer apparatus and method using geothermal brine

Abstract

A multi-effect system for using the heat, water and solids content of geothermal brine to produce useful work, fresh product water and inorganic salts. A flash separator receives brine from a geothermal well and provides the initial steam forming the heat source for the brine flowing through a first effect of the system. The system has a number of effects in series with each effect having means for generating steam from the brine flowing through it, and using the generated steam to provide the heat source for the next adjacent effect. Steam from each effect is also moved in heat exchange relationship to a binary fluid in a closed loop containing a gas turbine so that the binary fluid can be heated sufficiently to drive the turbine, the latter, in turn, being coupled to a work-producing apparatus, such as a generator. In one form of the invention, the steam to heat the binary fluid is the uncondensed part of the steam used as a heat source for each effect. In another form of the invention, this steam is part of the steam generated in each effect. Condensate formed in each effect from the steam received thereby is transferred to the next adjacent effect and, from the last effect, the condensate is drawn off as fresh product water. Brine blowdown removed from one or more of the effects provides the source of inorganic salts. As disclosed herein, the effects are vertical tube evaporators.