Distribution of Impurities and Gases Between Steam and Water Phases of the Geothermal Fluid in the Low Pressure Zone

Abstract

It is well known, that there is no uniform distribution of impurities and gases between steam and water phases of the geothermal fluid during the separation process in the fluid collection and distribution system of the geothermal power plant.

Also, it is known, that steam at thermal and nuclear power plants contains as much impurities and gases as it follows from the distribution coefficient Kd=(Cst/Cw)=f(ñw/ñst), where Cst and Cw – concentrations of the chemical compound in steam and water phases correspondingly, ñw/ñst – ratio of densities of water and steam phases. The ratio of concentrations of impurities and gases in steam and water phases depends on ratio of densities of these phases and have linear behavior in the logarithmic coordinates for the wide range of pressures, series of these rays which start from the critical point of water in P-V diagram was called – “Ray diagram”.

These dependences were discovered by Soviet scientists more than 55 years ago and then were proved by many experiments and tests. Domestic and foreign experiments were done in the wide rage of pressure (3 < P < 300 bars), however during the whole of that time (more than 45 years) the survey pressure range very seldom went down lower than 70 bars and experiments with the geothermal fluid were never done.

Our surveys show, that for the geothermal fluid (steam – water) the ratio Kd=f(ñw/ñst) has a nonlinear behavior for the whole series of impurities. This is a geothermal fluid characteristic, since it may contain up to 2000 of different chemical elements and compounds, impurities and gases with total concentration of those many times higher than in steam or feed water of thermal and nuclear power plants.