PSAT Qualified Specialist's Assessment Helps Texas Power Plant Reduce Pumping System Energy and Maintenance Costs
July 1, 2005
There was definitely a problem with the circulating water pumps at Austin Energy's Decker Creek Generating Station. The two 1000-horsepower pumps were supposed to deliver cooling water from a lake to a condenser for the Texas power plant's 405-megawatt steam turbine. However, during one of their regularly scheduled reviews, plant personnel found that the pumps were not delivering the amount of cooling water needed, even though they were operating at full load. They decided that a pumping system assessment was needed.
The assessment was performed in part by Alan Flory, U.S. Department of Energy (DOE) Pumping System Assessment Tool (PSAT) Qualified Specialist at Flowserve Corporation, a DOE Allied Partner. It revealed that the system's flow rate was well below its design rating, pump efficiencies were only 50%-55%, and turbine backpressure was increasing. In addition, the pumps were vibrating severely, sump vortexes were frequent, and surfaces of the impellers were severely eroded.
The solution was to develop a project that would significantly improve the system's efficiency and output capacity. As a result of this project, which was completed in 2004, the system's flow rate has increased to 11.5% above its design rating. And pump efficiency is now 85%.
Today, the Austin power plant can operate at full capacity using only a single pump. Its energy use is lower by 220,000 MMBtu annually, and it is saving $1.2 million per year in both energy and maintenance costs. The methods used in this project can be applied to most power plants and other industrial facilities that require water for process cooling.