In short: Downstream of scrubbers, desulfurization towers and wet ESPs, flue gas is saturated and acidic, and condensate attacks carbon steel. FRP stacks resist that corrosion. Our catalog gives a design temperature of −40 to 220 °C depending on the resin and a design service life of more than 25 years, 3–4 times that of carbon steel stacks.
Why steel stacks corrode
When gas is cooled to saturation in a scrubber or wet FGD, acid condenses on the stack wall. Carbon steel then needs linings, coatings and frequent inspection. FRP uses a resin-rich corrosion barrier that is chosen for the gas composition, so the wall itself resists the condensate.
| FRP stack | Carbon steel stack | |
|---|---|---|
| Corrosion in wet acid gas | Resisted by resin selection | Needs lining or coating |
| Design temperature | −40 to 220 °C by resin system | Higher dry-gas temperatures |
| Design service life (catalog) | 25+ years | FRP is 3–4× longer (catalog) |
| Weight | Light; smaller foundations | Heavier |
Temperature is the limit to check
FRP suits wet, saturated gas. Hot, dry gas above the resin limit, or bypass conditions when a scrubber trips, must be assessed: the design temperature range is −40 to 220 °C depending on the resin system, and a quench or emergency cooling may be needed to protect the stack.
Self-supporting or frame-supported
Stacks can be self-supporting or carried by a steel frame, per project. Height, diameter, wind and seismic loads, and the number of flues set the structure.
Connecting the system
Connect the stack to the scrubber or fan with FRP ductwork and FRP fans. See FRP chimneys and stacks for options.
Watch: FRP Chimneys vs Steel in 27 Seconds
FAQ
Is FRP suitable after a wet FGD?
Yes. Saturated, acidic gas after wet desulfurization is the main use; the resin is chosen for the gas composition and temperature.
What about upset temperatures?
Give us the maximum and bypass temperatures. Above the resin limit a quench or cooling system is needed.
Values in this guide are catalog design and selection references. Final sizes, laminate and performance are confirmed in writing in the quotation for your operating data.
Related guides
Next step: Send gas composition, normal and upset temperatures, height and diameter. Send it through our quote form and we will reply with a sized proposal.