FRP storage tank is a kind of glass fiber reinforced plastic products. It is a new type of composite material mainly made of glass fiber as a reinforcing agent and resin as a binder through microcomputer control machine winding. FRP storage tanks are widely used in different industries due to their anti-corrosion, high strength, light weight and long service life, especially the characteristics of flexible design and strong manufacturability. For example: chemical, environmental protection, food, pharmaceutical and other industries, and is gradually replacing most of the market areas of carbon steel and stainless steel.
Clarkson, a professor of engineering, does not manufacture composite tanks, but he knows very well what makes such tanks durable. He provides engineering and inspection services for the composites industry. Over the years, he has evaluated dozens of FRP storage tanks using non-destructive testing systems. He said that the prospects for most of these compound assets are very optimistic.
Clarkson said: "The composite material seems to have greatly exceeded the expectations of designers, manufacturers and component material suppliers. This is really a good result." Especially the oldest storage tank inspected-a 62 Historic storage tank. The factory owner knew that there was no leakage from the tank, but was not sure if other damage had occurred. Therefore, he conducted an ultrasonic analysis and the results showed that the tank still performed very well in a highly corrosive environment.
Since the storage tank was built and installed in the late 1950s, the composites industry has undergone tremendous changes. In addition to increasing customer expectations and the many standards and regulations surrounding the use of FRP in storage tanks, materials and technology have also made great progress. But the life of composite materials is still one of its strongest selling points.
Factors affecting material selection
Although the long life of composite materials is attractive, it is not the only decision factor that end users need to consider when choosing tank materials today. FRP storage tanks are lightweight, high-strength. The relative density is between 1.5~2.0, which is only 1/4~1/5 of carbon steel, but the tensile strength is close, even more than carbon steel, and the specific strength can be compared with advanced alloy steel. The tensile, bending and compressive strength of some epoxy FRP can reach more than 400Mpa.
FRP is a good anti-corrosive material, and it is resistant to the atmosphere, water and general concentrations of acids, alkalis, salts, and various oils and solvents. It is also an excellent insulating material used to make insulators. Good dielectric properties can be protected at high frequencies. FRP has low thermal conductivity, 1.25 to 1.67 kJ/(m·h·K) at room temperature, only 1/100 to 1/1000 of metal, and is an excellent thermal insulation material. In the case of instantaneous ultra-high temperature, it is an ideal thermal protection and ablation-resistant material, which can protect the spacecraft from high-speed air flow above 2000 ℃.
Various structural products can be flexibly designed according to needs to meet the requirements of use, and the product can have a good integrity.
Due to the design flexibility of the FRP storage tank and the excellent structural performance of the tank wall, fiber-reinforced FRP can change the physicochemical properties of the high-speed FRP storage tank and non-standard devices by adapting the resin system or reinforcement materials to meet the needs of different media and working conditions. Adjust the bearing capacity of the tank through the structure layer thickness, winding angle and wall thickness structure and design, and make glass fiber reinforced plastic storage tanks and non-standard devices with different pressure levels or some special properties. This is an isotropic metallic material Compared.
In addition, the structure, purpose and budget determine the customer's choice. For example, in the water and wastewater markets, most water tanks are made of concrete, fiberglass-reinforced plastic, and high-density polyethylene (HDPE). HDPE is cheaper than GFRP, but its service life is not long.
With the development of HDPE technology, the ground storage tank market has changed 20 years ago. As the material became stronger and stronger, part of the market made an economic decision to buy a cheaper product that might need to be replaced within 10 or 12 years instead of a fiberglass storage tank.
Another option in the storage tank industry is a double-layer laminated FRP composite material, which combines a thermoplastic lining and a glass fiber exterior. Because customers need storage tanks that can store high-temperature gases or liquids that are more corrosive or have higher pressures, double-layer laminates are becoming increasingly popular.
Advances in materials technology
Increased end-user demand has driven innovation in composite materials. Suppliers use new resin and fiber technologies to help solve problems. "The materials have improved." The relevant person said, "We are still using resin and fiberglass to make the water tank, but the new technology allows us to provide customers with better corrosion resistance and improve the efficiency of the plant.
Increasing efficiency is critical for manufacturers seeking a competitive advantage. Ineos is one of several resin suppliers that have introduced new products with higher efficiency to the market. In 2018, Ineos launched its Derakane™ Signia™ series of alkylene oxide vinyl ester resins. This formula provides faster laminate consolidation, lower foaming and reduced sanding. It is suitable for secondary lamination.
Derakane™ Signia™ resin can also improve curing kinetics. This allows manufacturers to process thicker parts. The parts do not generate excessive heat when cured, so they do not warp, distort or burn. In addition, the new resin also includes a new type of vapor suppression technology, which can form an air-activated film, thereby reducing styrene emissions during the curing process.
Ineos and other leading material suppliers have made advances in resins based on reliable technologies that have made composite materials into tanks in various industries (from chemical processing and mining to wastewater treatment, pulp and paper) An attractive option. Composite materials have the characteristics of corrosion resistance, high strength, light weight and good flexibility, which are required by a nuclear power plant in the northeastern United States.
The nuclear power plant requires three 10,000-gallon storage tanks to store chemicals in its existing facility. It is required to build storage tanks that are easy to install in existing structures. Each cylindrical water tank was manufactured with four independent parts-bottom, two middle parts and top. In early 2020, these fragments will be transported to nuclear power plants,
Compared with other materials, FRP has greater flexibility and more choices. If you find that there are structural problems after entering the site, it is very easy to make changes on site. You can cut another hole or place the accessory in another location. Alloys can be welded on site, but composite materials do not require traditional welding methods, so there is no need to worry about open flames or problems caused by welding.
When customers do not understand composite materials, over-design can also occur. Three 13-foot-diameter and 31-foot-long storage tanks were recently produced to store hydrochloric acid. In addition to storage tanks, GFRP saddles were also produced to support horizontal storage tanks. The interior of our saddles is usually hollow, but end users are hesitant to use hollow saddles, they think the support is not enough, so we filled the saddle with resin to provide additional strength characteristics. It is not required for support, but this design will reassure end users.
According to Clarkson's experience, when a storage tank fails, it is usually not a material or structural problem. He said: Many of the problems people encounter on FRP are related to the way the storage tank is installed in the factory and what happens, such as abnormal processes, temperature fluctuations or pressure peaks.
Working with designers and engineers during the design process, in addition to reducing over-design, can also help resolve process anomalies and other field failures. Clarkson said: "It is worthwhile for manufacturers to really ask the end user about their process control." For example, if the manufacturer asks the customer to fully explain where and how the tank will be used, Then they may provide design suggestions to address potential problems of temperature deviation, pressure peaks and other problems.
Because someone made a shortcut in the design stage, many failures or near failures occurred. Well-designed and well-made FRP tanks are almost maintenance-free and have a service life of decades. The composite storage tank can be used for a long time, or even longer. But we very much need to provide good advice on suitable services and the service life of oil storage tanks worldwide.
Cooperation is the key to market growth
The best way to promote the application of composite materials in the market is to let industry experts work with their peers, as well as engineers, designers, consultants and others on the market. Ultimately, sharing ideas and knowledge instead of keeping silent on professional knowledge and not working in silos will benefit the entire composite industry.