Pulp & Paper Bleach Plant

Project Background

A pulp mill's bleach plant had a failure history that ruled out the easy answers. Chlorine dioxide — the bleaching chemistry at the plant — destroyed coated carbon steel platforms within 3–4 years despite protective coatings, and even standard FRP grades failed within 5 years when the resin system was not matched to chlorine dioxide service. Caustic exposure in adjacent process areas added a second chemistry that had to be survived on the same walkways. The mill needed a material with documented, test-validated resistance to its specific chemistry — not a promise — and no appetite for another recurring replacement cycle.

Design Parameters

Engineering Approach

The defining step was validation before supply: the vinyl ester formulation's chlorine-dioxide resistance was documented against published test data and reviewed with the mill's engineering team before the PO — a requirement born directly from the plant's history of failed "standard" grades. Platforms and profiles were supplied as a matched system so load paths and hardware were consistent. Cut edges in splash zones were sealed to remove the one weakness where chlorine dioxide could attack a laminate — exposed fibre ends — and stainless hardware removed the corrosion path steel fasteners would have introduced.

Measured Outcomes

• 10+ years in service with zero platform replacements — versus 3–4 year cycles for coated steel and 5 years for unmatched FRP grades.
• Validated resin chemistry carried the chlorine dioxide exposure with no visible attack at inspection points.
• Adjacent caustic areas survived on the same system without separate material handling.
• Recurring replacement budget eliminated — the mill's walkway line item moved from recurring to one-off.

What Made It Work

Chlorine dioxide is unforgiving to laminates that are not formulated and edge-sealed for it. The project worked because validation preceded supply: test data reviewed before order, formulation matched to the exact chemistry, and edge detailing that closed the attack path. Any plant with an aggressive chemistry should demand the same evidence before accepting a resin grade.

Engineering Notes

Bleach plant platforms sit over chlorine dioxide, caustic and acid service — the resin list decides the platform life: vinyl ester covers most bleach-plant zones, novolac extends into the hottest strong-acid service, and every chemical is verified at its concentration and temperature against the compatibility chart. Grit-top handles the wet traffic; SS316 hardware avoids the galvanic failures that mixed alloys invite; and the corrosion-proof construction removes the repaint cycle of steel in the same atmosphere.

What to Specify

• Vinyl ester for bleach zones; novolac for hot strong-acid service.
• Chemical list verified at concentration and temperature.
• Grit-top on wet traffic surfaces.
• SS316 hardware throughout.

• Vinyl ester for bleach zones; novolac for hot strong-acid service.
• Chemical list verified at concentration and temperature.
• Grit-top on wet traffic surfaces.
• SS316 hardware throughout.