New steam path for turbine feed pump boosts efficiency

EthosEnergy has completed a full inspection, repairs, testing and reassembly of a Westinghouse boiler feed pump turbine for Coyote Station, bringing the unit located near Beulah, North Dakota back to full load. Coyote Station is operated by Otter Tail Power Company headquartered in Fergus Falls, Minnesota.

The Coyote Station boiler feed pump turbine experienced an overspeed event that resulted in a failure of the steam path and severe damage to the casing and bearing brackets. EthosEnergy provided an alternative solution to replace the steam path with a modern design that has enhanced thermodynamic performance and ease of maintenance, which allowed Coyote Station to get back to full load sooner than if they were to purchase a new turbine assembly.

EthosEnergy's solution was to manufacture a new modern designed rotor, blades, diaphragms and repairing the nozzles, valves and bearings. In addition a full casing overhaul was employed to straighten and realign back to specification. Following shop repairs, the boiler feed pump turbine was returned to the Coyote Station where EthosEnergy provided full non-destructive testing, sole plate regrouting, alignment and reassembly.

Brad Zimmerman, Coyote Station Plant Manager said, "The efficiency improvement was projected to be around 3% however, we are now getting closer to 7% - 8% improvement out of the boiler feed pump turbine."