Preventing Corrosion in a Pressure Vessel Exposed to Acetic Acid
Knovel helps a manufacturing engineer solve a serious corrosion problem in a product vessel, improving the safety of the operation and making it easier to maintain product quality.
An R&D executive at a chemical manufacturing company explains how Knovel helped provide a solution that enabled his engineering team to pinpoint the root cause of a corrosion problem in their product vessels. As a result, they were able to implement a process change in time to avoid substantial contamination costs.
A leading global manufacturer of oxidizing chemicals faced a significant corrosion problem in its metal tanks. The tanks contained the final product of a peracetic acid. Shortly after the tanks were installed, a standard safety check revealed that they were quickly undergoing corrosion in areas where the tank was exposed to vapor. No corrosion was evident where the tank was in contact with liquid.
If this corroded metal continued to mix with the product, the resulting peracetic acid would become impure and unsellable. In addition, the corrosion would create significant safety hazards in the manufacturing facility. A cracked tank could result in a dangerous spill of caustic materials and release hazardous vapor into the environment. The team had to find a solution and they had to do it fast.
To find out exactly how the vessel needed to be modified, the engineering team leveraged the vast repository of chemical data on Knovel. They began by running highly targeted searches on Knovel to access results vetted by experts and tailored for engineers. So when a process engineer performed such highly technical queries as
What’s the vapor pressure of acetic acid? and
How does stainless steel 304 behave with other acids with regard to temperature? she knew she would get quick, accurate results.
Once the process engineer found the relevant tables of acetic acid safety data, vapor pressure, vapor corrosion and compatibility with stainless steel, Knovel helped her quickly zero in on the right entries. The engineer was then able to understand the unusual interaction of the solution with the tank and pinpoint the cause of the corrosion: an unexpectedly high temperature was raising the pressure in the tanks, resulting in the formation of acetic acid vapors that accelerated corrosion of the steel. To solve the problem, the engineering team simply moved the tanks out of the sun to avoid higher temperatures.
"Knovel makes it really easy to find the chemical properties I’m looking for, even if they’re buried in a dense table or a large graph. It saves me so much time." Process Engineer
Resolving the corrosion issue not only improved the safety of the company’s operation but also made it easy to maintain the quality of the final product — and preserve the company’s reputation. The product costs up to $1.25 per liter to manufacture, so with three tanks containing more than $50,000 of product apiece, each batch costs more than $150,000 to produce. The innovation executive and his engineering team avoided the high costs if contamination made a batch unsellable.
The data our engineers found on Knovel led us straight to the root cause of the problem, which we’d been struggling to pin down, Byun says.
*Name has been changed to protect rights to innovation