Aeration of Boone Unit 2 Discharges Using Air Blowers, Summer and Fall of 1983

摘要

This project has three identical vertical Francis turbines each rated at 34,500 hp at 90-foot net head. Tests conducted in 1982 using portable compressor-eductor systems on Unit 2 had indicated that injecting compressed air under the turbine headcover could be a suitable method for aeration of the turbine discharges. To investigate potential long-term problems of this method of aeration, both a rotary-lobe type and a centrifugal type compressor were installed at the plant to aerate Unit 2 during the summer and fall of 1983. Evaluation tests were conducted on August 17, when the gross head on the unit was about 120 feet. Each compressor supplied 60 to 65 scfs of air over the full range of gate openings tested, thus producing total airflows of about 120 to 130 scfs and airflow/waterflow ratios from 2.4 to 4.4. Near the most efficient operating gate opening (best gate), unit efficiency was lowered about 0.8 percentage points when the air was present. Oxygenation efficiency near best gate was about 50% which indicates that dissolved oxygen (DO) uptakes on the order of 3 to 4 mg/L would be obtained if the incoming DO were 1 mg/L or lower. Power output was reduced about 1 MW when air was injected at the maximum gate opening of 92%. (ERA citation 09:039850)