HOW pervasive is corrosion in cargo tanks?
The Walker Group’s John Cannon said that in the opening stages of Tank Truck Week, he was approached by representatives from at least 10 major carriers and several smaller fleets saying that 2014 was the worst year they had ever seen for tank corrosion.
“So certainly the problem persists,” said Cannon, vice-president of engineering at The Walker Group of Wabash National.
NTTC is hoping to make a dent in corrosion with the introduction of the Liquid Products Database (LPD), which was first discussed in June 2012 and officially rolled out during 2014 Tank Truck Week in Houston, Texas.
In “Corrosion Prevention Initiative: An Update and Unveiling of the Liquid Products Database,” Cannon and Doug Pape of Battelle outlined some of the benefits of the LPD and delved into some examples of the scourge of corrosion.
Cannon said a steering committee was meeting as often as monthly just to give direction and input, along with identifying and addressing roadblocks, and Battelle was retained by NTTC in May.
“We are focused on reducing the impact of corrosion within the transportation tank,” Cannon said. “Corrosion on the exterior of mobile equipment is an issue, too. Until such time as the LPD is fully functional as a tool to carriers, this endeavor will be the sole focus of the Corrosion Steering Committee. It won’t focus on other opportunities related to corrosion. We understand the challenge is much greater than having a comprehensive database.”
He said the three pillars of the LPD are compiling existing data, limited annual laboratory testing of new chemical solutions, and a carrier comment corner.
The objective of the LPD is to put information on corrosion at the carriers’ fingertips, whether it’s through a PC, tablet, or smart phone, which will allow for prompt—and more accurate—decisions about accepting a shipment. Cannon said the project has been successful in collecting corrosion data from handbooks in the public domain, with Pape and his colleagues already putting together more than 4,000 data points.
But they’re not having success in getting input from participating carriers.
“It’s up to you to make it better,” he said to the tank fleet managers attending Tank Truck Week. “A very small minority of chemical carriers have supplied any data. This could be a whole lot more effective if only 50% of chemical carriers provided data to Battelle.”
Pape said new features requested by users are licensed handbook data, more metals, and more materials. There is a draft protocol in place that will feature coupons being placed in a liquid setting, weighing them before and after, and microscopically examining them for pitting.
Also in the works in a year or two is a carrier comment corner.
“It will be kind of like a moderated chat room,” Pape said. “Right now, you’ve been sending in comments and a corrosion engineer has been verifying the information, and then we make an entry. Maybe we can have a chat room back and forth, and one of our engineers will moderate comments.”
Cannon said LPD is a journey, not a destination.
“We’re not going to be able to be complete next year or the year after that,” he said. “We’ll always be adding data to the LPD, and the LPD in and of itself is not going to solve corrosion. Many variables contribute to corrosion, not just chemicals, not just materials, but also temperature, concentration, and a whole host of other factors. We as a steering committee plan to address these once LPD is up and running, maybe with white papers or documents.”
Cannon showed some examples of corrosion that are in the LPD, including a chemical tank trailer that hauled six to eight loads of a certain product group. It would cost over $40,000 to repair, but the unit was 20 years old and worth only $20,000, so the tank was essentially totaled.
• 1989 MC307 trailer. Hydroxy carboxylic acid is suspected of causing serious damage. The fleet previously listed this product as “haul” in a stainless steel tank trailer, but “no storage.” Now, the listing has been changed to “no haul” in SS.
• 1989 MC307 trailer. Magnesium chloride was determined to caused corrosion damage to this trailer in 2013. With winter approaching, carriers will have many “opportunities” to haul this product. “If you’re invited to haul mag chlorides or liquid, you might want to think twice about doing it in a stainless steel tank,” Cannon said.
• 1995 DOT407 tank. Alkyl phosphite, listed as an oil additive, was frequently hauled in this cargo tank motor vehicle.
• 1999 DOT407 trailer. Phosphoric acid was hauled on a dedicated basis in this cargo tank motor vehicle.
• 1998 DOT407 tanker. This trailer was in general chemical service. Formaldehyde, butonal, methyl acrylate, butyl acrylate, and sodium lignosulfonate were the most frequent products hauled. The exact corrosion perpetrators were not determined with certainty.
• 2002 DOT407 trailer. Acrylic acid, potassium hydroxide, and “scale inhibitor” were the products hauled in this cargo tank motor vehicle in dedicated service.
• 2006 DOT407 tank. This trailer was in general chemical service. Butyl acrylate, phosphoric acid (70%), styrene monomer, vinyl acetate, and methanol were the most frequent products hauled. The exact corrosion perpetrators were not determined with certainty.
“Corrosion is pervasive, whether it’s a new tank or an old tank,” he said. ♦
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