Written by Scott Schreeg | Power Plants
SVI BREMCO recently completed a stack silencer replacement at a combined cycle power plant in South Carolina. The project retrofitted the HRSG stack silencer during a planned plant outage to improve the silencer system’s durability. In reviewing the original equipment design, we found many opportunities to improve the silencer’s design and durability.
What Type of Silencer Baffle Work Was Needed?
To retrofit the HRSG stack silencer in the combined cycle power plant, SVI BREMCO provided turnkey (EPC) support with in-house resources, including design, engineering, and construction. The customer was delighted we could self-perform the field retrofit (demolition and erection), as it reduced their risk of two vendors pointing fingers if a problem came up during execution. The prior year’s inspection during a planned outage gave the project team a clear view of the project scope. On the unit to be worked on, about 1/3 of the existing baffles appeared to be wedged or stuck in the existing silencer supports. Fortunately, the previous inspection gave the team insight into the best removal method, given the excessive weld material on the existing guides and the stack damper arrangement under the baffle supports.
Project scope highlights included:
- SVI BREMCO installed new guides in 18-inch sections starting from the support plate and a 24-inch section at the top baffle.
- Replacement silencers and mounting components will be of upgraded construction designed by the SVI in-house director of acoustical engineering as follows:
- Silencer perforated sheet upgraded to 12Ga 409 stainless steel for better corrosion resistance
- Acoustical fill to be upgraded to 6PCF mineral wool
- Includes standard drain holes for moisture removal
- Revised silencer design to eliminate tails and incorporate standard silencer active length with aerodynamic radius at silencer exit. The stack silencer baffles from Sound Technologies utilized a tapered tail as part of the silencer active length. The new design eliminated the tail and replaced it with an extension matching the thickness of the rest of the silencer baffle. The tapered design was intended to improve flow distribution at the silencer exit, but CFD analysis showed this can be achieved with a rounded, aerodynamic edge like the silencer inlet. This provides the same or better acoustical and aerodynamic performance and is more durable.
What is the Typical Sequence for this Retrofit?
The SVI BREMCO team performed the following steps to replace silencer baffles in the power plant unit:
- Removed 18 original silencer baffles
- Staged the new silencer baffles in order of installation
- Inspected and performed NDE on silencer baffle supports inside the stack
- Prepared new guides for installation
- Installed bottom level of silencer baffle supports, middle row of guides, and upper row of guides
- Installed new silencer baffles in the unit
The silencer baffle replacement project was completed safely and on time within the 15-day outage schedule.
Does Your Power Plant Need a Silencer Baffle Replacement Like This?
At SVI BREMCO, we provide industrial noise solutions for power plant applications, including silencer baffle replacement. Our team has extensive experience in industrial noise control and is a leading turnkey supplier for all your gas path support needs. Our engineers design innovative solutions to help you meet all your acoustic project goals. If your plant’s acoustical system needs a professional inspection, repair, or replacement, contact SVI Dynamics today to schedule an inspection and receive comprehensive repair recommendations and installation.
SVI BREMCO can also help with silencer inspections using our in-house drone and licensed pilot. This is a quick, safe way to get a thorough visual inspection of the equipment, giving the plant the information it needs to make informed decisions and assess equipment life.