A New Air-Cooled Condensing System for Both Geothermal Steam and Conventional Steam Power Plants

摘要

The heat rejection system of a thermal power plant is the equipment that condenses the vapor exiting the turbine, and then releases that heat to the atmosphere by either heating ambient air in a dry cooler or by evaporating water in a cooling tower. The heat rejection system of geothermal power plants claims a disproportionately large share of the capital cost and the parasitic load, in comparison to fossil-fuel power plants, because of much lower turbine inlet temperatures. No commercial air-cooled geothermal steam power plants have been built, but there is a need in some geothermal fields to avoid evaporation of the condensed steam in cooling towers, usually to increase injection. The paper describes an air-cooled heat rejection system for a geothermal steam turbine power plant. It uses a conventional geothermal direct contact steam condenser and flat-bundle air-coolers, like those on a binary power plant. An option is described to do dry/wet hybrid cooling by adding a small cooling tower. The same technology combination can also potentially be applied to conventional fossil-fired power plants as an alternative to large and expensive steam air-cooled condensers. Areas for future work and investigation are discussed.