Since the 1960s, the steam turbine located at the University of Washington’s power plant has served to provide uninterrupted power to both the campus and university’s hospital during utility outages.
However, as time went on, the steam turbine was gradually nearing the end of its useful life, and its reliability began to wane. It could no longer meet its primary objective of providing dependable auxiliary power. Stanley Consultants was brought in to help upgrade the plant and protect its operations during future utility outages.
To improve reliability, the decision was made to demolish the existing turbine and opt for the implementation of a Diesel Rotary Uninterruptible Power Supply (DRUPS) to provide backup power to the plant. The DRUPS proved to be a more dependable alternative, particularly in the event of a grid failure, which wasn't necessarily the case with the old steam turbine.
At the start of the project, the plant operated with two different steam systems, 425 psig superheated and 185 psig saturated. The removal of the steam turbine from the plant eliminated the need for the 425 psig system and helped simplify the operation of the plant. The superheaters and the associated 425 psig steam system were then removed, enabling all boilers to operate at a common pressure and temperature.
This streamlined operations and enhanced the reliability of steam generation, as there were now more boilers to choose from in case of a failure. A new, smaller steam turbine was installed to capture the energy associated with the pressure reduction. This allowed the university to recover unused energy from the 185 psig system as they dropped pressure to 10 psig for campus steam distribution.