UltraAnalytix™ inspection results showed that the thickness and condition of the FRP in a pulp bleaching vessel were adequate to postpone scheduled relining.
Background: The Owner Company operated a pulp and paper mill in British Columbia, Canada. Five seal tanks are used in the bleach plant, three of which contain chlorine dioxide filtrate. Chlorine dioxide is particularly corrosive to FRP, and often results in loss of FRP thickness.
Two of the three chlorine dioxide filtrate tanks were relined internally after 20 years in service based on internal visual inspection. The third chlorine dioxide filtrate tank (Seal Tank 15) is 28 years old and has never been relined.
The previous FRP inspector had recommended relining of Seal Tank 15 since 2015 based on internal visual inspection, and relining was scheduled for the plant shutdown in March 2017. UTComp, Inc was hired to inspect Seal Tank 15 in advance of the scheduled plant shutdown.