Case Histories

Fluoropolymer Lining for a Chlorine Scrubber

A chlorine scrubber fabricated from fiberglass-reinforced plastic (FRP) was installed in 1977. Major repairs began in 1981 and continued at four-year intervals. After exploring several replacement materials, a FRP/ethylene-chlorotrifluoroethylene dual laminate scrubber was selected. This was installed in 1987 and remained in continuous service until the plant shut down in 2001. Examination shortly after plant closing showed the liner to be in excellent condition.

Case History: Preferential Weld Corrosion

Preferential weld and heat-affected zone corrosion is directly proportional to the process flow, temperature, pH, location of welds within the piping, and how active the weld metal is electrochemically when coupled to the base metal. Accelerated decay and possible reasons for this attack are illustrated in this case study.

Performance of Concrete Bars on Industrial Platform Substations

An electric company tested concrete construction members from substations in chemically aggressive environments to determine their load-carrying capacity after ~35 years of operation. This article describes the manner in which tests were performed and summarizes the results.

Evaluation of the Scale and Inhibition Effect of a Water Stabilizer

The complex effect of a water stabilizer on copper, iron, and zinc ions was tested by spectrophotometry, and its corrosion inhibition on copper alloy tubes was measured using electrochemical methods. The results showed that the water stabilizer not only had a strong antiscaling effect on Ca2+ and Mg2+, but also had certain complex effects on Cu2+ and Zn2+ under conventionally used concentration. The water stabilizer provided insufficient corrosion inhibition on copper tubes at the usual concentration.

Hot Oil Aboveground Storage Tank Bottom Corrosion Failure and Cathodic Protection Upgrade—Part 1

There are several types of anode installations that distribute protective current to a tank bottom. In some cases, however, the methods selected do not always produce the desired results. This two-part article discusses a case history in which existing cathodic protection (CP) was ineffective and the methods used to verify the performance of CP did not identify system deficiencies. This led to the premature failure of a tank bottom. Part 1 covers the findings of an investigation conducted to identify the cause of the corrosion. Part 2 discusses the remedial approach taken to enhance the CP for effective corrosion control.

Di-Octyl Sebacic Acid in Epoxy Paint Leads to Blistering in a Drum and Barrel Manufacturing Plant

Di-octyl sebacic acid (DOS-A) is used as rust preventive oil on steel sheets. When applied below the maximum level of 75 mg/m2 per side, it is compatible with epoxy paint and does not require any pretreatment of the steel sheets. The incompatibility of DOS-A above this maximum could be caused by weak H-bonding between the acid and epoxy molecule, leading to blistering. The optimum oil level was determined through experimentation to avoid paint failure. It was also observed that a variance in the sheet surface roughness of ±0.4 µm did not appreciably affect paint failure.

Tracking Corrosion in Real Time in a Carbon Dioxide Capture Plant

Due to advanced plant process control system technology being used to regularly monitor plant process conditions, it is possible to incorporate online corrosion monitoring technology that can send real-time corrosion data to the plant where they can be regularly monitored along with process control data, making it possible to correlate changes in corrosion rates with process events. The real-time monitoring was tested in a carbon dioxide (CO2) capture and sequestration (CCS) plant.