Challenge

Issue
Severe cold wall corrosion attacked the high nickel alloy of the ducting. The plant was forced to make weld over-layment repairs and re-cladding every 6-8 months.

Goal
Extend reliability over eight months. Lower overall maintenance cost.

Root Cause
Elevates sulfur levels accelerated the rate of corrosion.

ARC S7 AR was selected.

Solution

Preparation
Surfaces were decontaminated and grit blasted to SP10 cleanliness with 3+ mil angular profile.

Application
Two coats of Chesterton ARC S7 AR at a total DFT of 30-40 mils. ARC S7 AR is a protective coating for high temperature, chemical exposures where erosive particulates and thermal cycling conditions may be present.

Test area of duct sfter nine months in service.

Results

Client Reported
Trial area inspected after nine months of exposure and found to be unaffected by exposure.

The client is scheduling expanding the trial area to full reline of raw gas ducting. During spring 2020 outage 2000ft² was lined with ARC S7 AR.