POWER stations are heavily regulated and one key measurement is the volume of water being used at any one time. This includes river water for cooling and normal water for steam generation. Excessive use incurs considerable fines.
Centrica Energy, part of the British Gas Group, owns and runs Killingholme Power Station in North Lincolnshire, a combined gas turbine (CCGT) power station which began operation in 1994. It can send out over 3,000GWh of energy annually when the station is running at full load. At present the station runs a two-shift system, which means they switch on and off twice a day allowing “a competitive station with low losses”.
The station uses fresh water which is then conditioned for steam generation. Two hundred gallons of water can be used daily, through a four-inch pipe from a mains water system. A flow meter is required to measure the volume metric flow rate which enters the storage tank; normal flow rate can be near 100m3 per hour. The original meter broke down in 2011 and was found to be obsolete; a new flow meter was fitted in April 2013.
Jon Dixon, Centrica’s Control Instrument Technician determined that to avoid costly and disruptive downtime in the plant the replacement flow meter would have to be easy to fix without any need to break into the system. He compared suppliers and decided that the Micronics Ultraflow 3000 offered the best value for money.
The device uses non-invasive ultrasonic sound transmission and detects liquid flow velocity inside closed pipes. It is said to be simple to operate, giving accurate measurements. According to Dixon: “When ultrasound is transmitted between the transducers, the speed at which the sound travels through the liquid is accelerated slightly by the velocity of the liquid through the pipe.