The use of resins and non-metallic fiber-reinforced polymer (FRP) is becoming a more common solution for corrosion issues that are often seen in industries such as chemical processing and mining. Stainless Steel World Americas had the pleasure of speaking with Michael Stevens, a Principal Scientist, and Joy Bennett, the Global Business Development Manager for INEOS Composites, at the Managing Aging Plants U.S.A. Conference & Exhibition, which took place in Houston, Texas. Stevens and Bennett discussed how the use of these non-metallic solutions can be applied in conjunction with metallic solutions, and that doing so, can reduce corrosion, maintenance, and extend the service life of process equipment.
By Catarina Muia and Angelica Pajkovic
Working at INEOS
A Polymer Chemist by training, Stevens began his journey at Dow Chemical in 1979 working in the resins research area. “I was working with epoxies and epoxy vinyl ester resins until 1985, when I took a position at Ashland.” The Ashland Composites division was recently acquired by INEOS Enterprises. Currently, Stevens works for the INEOS Composites business, working with corrosion-resistant and fire-retardant resins in product development and technical support.
With a background in Civil Engineering, Bennett has specialized in channel development and finding new applications for existing products in the construction, environmental, and industrial markets for the past 12 years. “For the past two years I have been working in the industrial segment with a focus on marketing and working with engineers to specify Derakane™ epoxy vinyl ester resins for corrosion-resistant FRP equipment.”
As part of the technical service team, it is Stevens’ job to help end-users understand where the corrosive issues are within the plant facilities. From there he determines if FRP is a good solution to prevent the corrosion, then matches the FRP with the correct resin depending on which chemicals and concentrations are used in the process.
As a Principal Scientist for INEOS Composites, Stevens’ main tasks involve answering technical questions from the customer, evaluating the processes that the specified applications are withstanding and after getting the information, determining the most appropriate material for long-term durability within the application.
“Essentially, I check to see if the FRP will work for that specific application, as well as determine what the correct resin is to use in the construction of the corrosion barrier for the application,” Stevens explains. “Typically these applications are seeing various acids and bases, and in these areas, simple carbon steel is not going to work. If you are having to use 316 stainless or even higher alloys, sometimes FRP can be the more economical option. Especially if an application needs to withstand chlorinated materials, which are extremely hard on most steels, it would be most ideal to use FRP.”
Benefiting various industries
The most common places to use resins and FRP are in pipe, tanks, and storage vessels within the manufacturing process. “Anything from the chemical processing or manufacturing of chemicals, to mining and extraction applications, to air pollution control that would be in a power plant facility; these are our key market segments,” Bennett states.
Other industries that would find the use of resins and FRPs ideal are pulp and paper, chemical processing, oil and gas, and mineral processing. “It is extremely useful when extracting the minerals out of the ore because they use an acid-based solvent extraction process,” Stevens continues. “This solvent extraction process is common in copper, nickel, cobalt, and lithium, and FRP equipment can be used for all of them.” In the water and wastewater treatment facilities specifically, FRP is used for the chemicals that treat water containing sodium hypochlorite, ferric chloride, and fluorosilicic acid.
The process of applying FRP
Generally, FRP is used in place of stainless steel when the environment will be hard on the metallic material. “Typically I say if you have to go to 316 stainless or a high-nickel alloy, FRP can be used as a replacement. However, you can apply an FRP lining inside a carbon steel or stainless steel vessel; that actually happens fairly often,” Stevens states. “In fact, I recently recommended and told someone how to apply an FRP lining to a stainless steel vessel,” he continues.
Depending on the section of a manufacturing plant and the chemicals being used in that section, it is quite common to see stainless steel in one section, carbon steel in another, and then FRP tanks or pipe in a different section. “It all de pends on what type of material is in the tank. That is what determines which material is going to give the best performance and provide the best service life,” Bennett says. “Our job is to match the correct material with the right part of the process.”
This matching process can become challenging however, when it is time to acquire the correct information. “It is my job to determine whether or not the resin is applicable to the specific situation,” Stevens explains. “A customer needs to provide details about the process, such as chemical concentrations, temperature and pressure ranges, and upset conditions. Oftentimes, some of the minor components a customer thinks are not important can be very critical information for us. They can determine whether or not the application is suitable for FRP.”
Stevens gives the example of a process involving hydrochloric acid (HCl). “We have several resins that can handle HCl, however there are specific HCls that contain chlorinated organic solvents as impurities in the HCl. In this case, there is only one resin we can use, Derakane™ 470. If the client does not give us this specific information, then the vessel will not last as long as it should.”
As a veteran in the industry, Stevens has a history, as well as an extensive amount of knowledge, on the topic of non-metallic solutions and is therefore capable of thoroughly understanding the process and asking all of the necessary questions in order to give the customer a recommendation that is going to work. “That is another big challenge I face as part of my job,” Stevens explains, “making recommendations can be tough. Some customers may have 20 different ingredients involved in the specified process and trying to find the right material that is going to withstand all of those can be tricky. I just need to make sure I am thorough; I need to focus on evaluating the process, getting all the information, making the right choice of whether or not FRP can be used, and if so, determining the correct resin to recommend.”
Knowing when to use FRP and resins
One point Bennett really stresses, is that it is extremely important to look at the temperature conditions that are specified for the application. “This is really going to determine whether stainless is better in a specific area or if something like a fiberglass tank would be better. In many cases, both can work, it really depends on how much the customer wants to invest and what service life they want to get out of it.”
In certain cases, where temperatures are on the higher side, the use of FRP can be more limited. “At around 200°F in liquid services, that is about as hot as we can go, stainless can withstand hotter than that. There are obviously a lot of solvents that require stainless, however with some others, there is really no difference,” Stevens explains. “If carbon steel can work, that is going to be your most effective material, it will be less expensive, especially without the use of FRP.”
The engineering department at INEOS Composites conducted a cost comparison of a tank made with several different types of materials. “When we compared the different materials and the prices, we found that an FRP and 304 stainless came to be about the same price, however 316 stainless or higher nickel alloys were generally more expensive.”
In addition to being less expensive, FRP does not require a coating on the surface. “This is a big advantage maintenance- and service-wise as you do not have to put any coating on the FRP equipment at all.” In cases where materials such as HCl, sodium hypochlorite, or ferric chloride are being held, FRP is the most cost-effective and will last the longest. “We have HCl tanks that can last up to 30 plus years, sodium hypochlorite tanks that are 20 years old, and a ferric chloride tank from Dow that lasted more than 45 years,” Stevens states. “If you really wanted to use a metallic material for something like sodium hypochlorite, titanium that would give you the longest life cycle. However, it is significantly more expensive.”
Educating and expanding the industry
As the topic of non-metallic products and solutions are not typically taught to engineers in college, Bennett explains that specialized training is needed in order to learn about them. “The engineers really need to understand what the failure mechanisms are for a thermoset material versus a metallic material,” she says. “Communicating and helping them design, as well as educating the engineering community is extremely important.”
In order to fill this knowledge gap, Stevens explains that engineers are encouraged to attend proper engineering seminars about FRP, as they can be highly beneficial. “We actually hold a lot of educational seminars for different engineering firms and asset owners,” he says. “I have been part of a few of them and I really enjoy educating the various companies.”
Educating the engineering communities is one of Bennett’s favorite parts of her job, “making that match, figuring out the correct solution, and putting the right people in contact with the engineering community, that is a process I always enjoy.” Even for those who are new to the industry, educating them in order to increase their knowledge is extremely important to both Stevens and Bennett.
“You will always have that knowledge gap between those who are fresh out of school and those who have had years of experience in the industry,” Stevens states. “Like I said before, schools do not normally teach non-metallic solutions and products. It is an extremely specialized topic and only a few schools in the U.S.A. have it as part of their curriculum, so it is extremely important to take the time to educate the newcomers.”
For more information on whether FRP equipment is suitable in your service environment, please see ineos.com/derakane, or email derakane@ineos.com.