An Emerson Process Management report identifies five key measurement priorities that should be a concern for any plant management team that is looking to reduce energy use.
1) Steam System– monitoring steam traps. Barking Power found a leaking steam trap that was costing them $2,200 per day.
2) Utility Fluids –metering flow and managing use. A paper mill in New England is saving $1 million a year by keeping closer track of their steam, air and water.
3) Compressed Air – measuring flow to identify leaks and manage use. In South America, a chemical plant is saving $750,000 per year with a better way to measure the flow of its compressed air.
4) Boilers – improving drum level measurement. In the United States, a paper mill has minimized boiler trips during start-up through more accurate boiler level measurements.
5) Heat Exchangers – predicting and detecting fouling. Oil refineries are using wireless instrumentation to give operators visibility to heat exchanger performance for lower fuel usage and better product quality.
In the case of boilers, a US paper mill was experiencing lost production and increased utility costs due to boiler trips during routine start-ups. Boiler trips were caused by an error in the boiler level reading of a DP transmitter installed with impulse lines. The DP level transmitter is calibrated for full boiler operating pressure and temperature. However, during start-up when the boiler was cold, water and steam density differences in the impulse lines were causing an error in the DP level reading. The solution was to supplement the DP measurement with a Rosemount 5301 Guided Wave Radar with Dynamic vapor Compensation. With more accurate level readings during all process conditions from start-up to full output, boiler trips during start-up were minimized.