Steam Flow Balance in the Los Azufres Geothermal System, Mexico

Abstract

The results of a steam flow balance performed for the U-15 and U-16 electricity generation power in the Los Azfures geothermal system in February 2009 are presented in this paper. An ActiveX component OrificeMeter based on the ISO-5167-2 formulation for an orifice meter with D and D/2 tappings was used. The plant U-15 was fed by the production wells AZ-04, AZ-40, AZ-65D, AZ-69D; whereas AZ-28A, AZ-45, AZ-56, AZ-67 were connected to U-16. The analytical error is within ±4%.

The geothermal fluid is separated into vapor and liquid components at the wellhead. Thus, the conditions of temperature and pressure of steam at the well separator are along the saturation curve and the measurement of pressure or temperature is sufficient at the orifice meter of the well. However, there is a need to measure temperature and pressure at the production units. Similarly, the measurement of the pressure difference across the orifice plate is crucial. For example, an error of 0.002 m Hg-water column across the orifice plate of power plant U-15 or U-16 is equivalent to 1 ton/hr.