Power Plant – Reheat Spray Valve Solution

Business Objective

Unit four was de-rated 25% because of the existing reheat spray valves. When the valves were operated, the piping vibrated severe enough to cause damage and a steam leak. Since the leak was then a safety concern, the valves were isolated until the problem could be rectified. Running the unit without the reheat spray valves could only be completed at a de-rated output. Prior to this problem, these valves had poor control and sporadic issues with valve position feedback.

Plan

Since a fast response was needed to correct this situation, we involved IVS personnel. ECI proposed using the existing valve bodies, but turning them around to accommodate a flow-up configuration. This way all that was required was to replace the existing trim, actuator spring, and position/feedback – a timely solution our client was looking for.  

Outcome

The valves were cut out and turned around by the plant. IVS worked with plant personnel replacing the trim and actuator springs.  IVS also installed new DVCs and Topworx positioner feedback transmitters for better control.

Results

Unit number four (175MW) was returned to full operating capacity approximately two weeks later. This resulted in a 25% de-rate and approximately $42/MW LMP price during this time. Safety concerns were also eliminated.