Lining Solutions from Plastic
Concrete, Steel, Fiberglass tanks, containers and other equipment lining solutions with plastic
ECTFE lining solutions
The life-prolonging lining of steel tanks with thermoplastics is one of the Tankplasta competencies. For this purpose, ECTFE sheets can be used inside of the tank with fixed-points and welded media-tight. Excellent chemical resistance combined with a higher temperature resistance makes ECTFE an indispensable material in the chemical industry. Simultaneously, a container lined with ECTFE can be cleaned easily and quickly due to its smooth inner walls.
ECTFE for the sulphuric acid plant. The formation of highly aggressive media such as SO2 and H2SO4 can occur by processing the flue gases. Since these media are very corrosive to metals and many other plastics, the ECTFE solution should be chosen.
An ECTFE piping and storage systems equipped against most aggressive media such as different acidic and alkaline solutions like NaOH (sodium hydroxide), H3PO4 (phosphoric acid), HCl (hydrochloric acid) and C2H4O2 (acetic acid). ECTFE tanks can be used as chemical resistant tanks to both acidic and alkaline solution. They can withstand an application temperature of up to 50 °C.
98% sulphuric acid or 79% phosphoric acid can be stored in the tank. These acids can reach temperatures up to 100 °C. As a storage container for acids, the steel tank must be permanently acid-proof because base metals oxidise when they contact aggressive media. An inner lining can be made of the high-performance plastic AGRU ECTFE sheets as the first choice for corrosion protection for these extreme applications. In contrast to conventional rubber linings, the ECTFE material permanently withstands the most adverse conditions. It can be used in a pH range of 1 - 14. Even 98 % sulphuric acid (H2SO4), 70 % hydrofluoric acid (HF), 50 % sodium hydroxide (NaOH) and 36 % hydrochloric acid (HCl) are safely handled up to +120 °C over a long time. AGRU ECTFE is also the first choice for highly oxidative applications such as sodium hypochlorite (NaOCl), chlorine gas (Cl2) and ozone (O3).
ECTFE possesses a unique combination of properties resulting from its chemical structure, which consists of a copolymer with ethylene and chlorotrifluoroethylene arranged alternately. ECTFE has excellent chemical resistance and shows almost no property changes over a wide range of temperature. Furthermore, ECTFE is known for its great permeation barrier, which ensures durability and longevity.
A high-voltage spark test can ensure tight welding if required.
Advantages of ECTFE material
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ECTFE has excellent chemical resistance to both alkaline and acid solvents
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ECTFE shows almost no property changes over a wide temperature range of up to 140 °C
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ECTFE is known for its sound permeation barrier for many chemicals
PVDF Chromic Acid Baths
Industrial hard chrome plating, cylindrical grinding, and surface treatment companies use PVDF material to manufacture chemical storage solutions.
Chromic acid baths can be designed from PVDF for such plants. Tanks can be made only from PVDF, or metal tanks can be lined with PVDF material.
AGRU PVDF, which Tankplasta is working with, is a highly crystalline, non-reinforced plastic that combines good mechanical, thermal, and electrical properties with excellent chemical resistance. A fully bonded lining made of fabric backed PVDF sheet material applied to steel provides a long-term chemical resistance at temperatures up to 120 °C.
PFA solutions
Due to its outstanding thermal and chemical resistance, the usage of PFA is expected in the chemical industry. Especially in the lining of flue gas ducts, chimneys and heat exchangers, the installation of PFA fix point linings is used as a state of the art method. The PFA lining can be used up to an operating temperature of 260 °C and shows excellent chemical resistance against condensation media like H2SO4, HCl and HF, typically present in power plant applications.
The semiconductor industry is also well known for its stringent requirement regarding the purity of water and chemicals. Additionally, these chemicals are often very corrosive. For cleaning of process equipment in the semiconductor industry, display production and thin-film solar cell production, Nitrogen Trifluoride (NF3) gas is often used. It is broken down in situ by plasma, and the resulting fluorine atoms are the active cleaning agent. There are different possibilities to produce NF3.
For the production of NF3-gas, electrolytic baths are widely used. AGRU PFA sheets used in these industries to provide adequate corrosion protection and a long lifetime for the analytical, electrolytic baths.
Ammonium Bifluoride (ABF) is a source to make NF3. By heating ABF up to 150 °C, the NF3-gas is generated. ABF and NF3 are very corrosive, especially at elevated temperatures. To provide adequate corrosion protection, PFA plastic solutions used for the tank for heating ABF at 150 °C.
Installation: Basically, different ways can be chosen to install AGRU PFA sheets. One of the methods is the fixpoint lining method when there is a need to meet extreme operating conditions. A welding bolt should be welded to the steel surface. Afterwards, the PFA sheet, a washer made of steel (optionally a PTFE disc can be added) can be positioned and tightened with a hex nut. Finally, the cover cap must be welded tight.
PFA has an outstanding chemical resistance up to 260 °C, which is very attractive in the semiconductor industry.
Containers for the transport of chemicals
Daily a large number of transporters are on the road to meet the ever-increasing demand for chemicals. Some of the media to be transported are aggressive acids, e.g., sulfuric acid, hydrochloric acid, nitric acid or sodium hydroxide. As most of the media are "dangerous goods transports", these transporters are subject to high safety standards. Furthermore, the logistics partners are interested in containers, which guarantee high-cost effectiveness and product quality and long service life.
Currently, most tank containers are made of stainless steel. Depending on the application, these tanks have an additional thermoplastic lining (e.g. PE, ECTFE, PFA) to protect the steel from corrosion. Due to the PE, ECTFE or PFA lining, these containers are showing excellent chemical resistance. A negative aspect of steel containers is the high weight, which reduces the container's maximum loading capacity; the law regulates this. Thus, the logistic partners are interested in a new solution to increase effectiveness.
A lined fiberglass-reinforced plastic (FRP) was recently introduced. Comparing the weight of a standard steel container with an FRP container, the FRP construction can achieve a weight reduction of approx. 1600 kg. Thus, it is possible to transport many chemicals, whereby the efficiency is significantly increased. To achieve the required chemical resistance to the media, Tankplasta can line tanks with PE 100, ECTFE and PFA produced by AGRU. These materials show excellent resistance to a variety of media, enabling a long-lasting product solution. Another positive effect of the plastic lining relates to the easy cleaning of the plastic-lined container surface. In the case of a medium change, both the cleaning time and the required amount of cleaning agent (water, aids) can be lowered compared to a steel surface. Easy cleaning also reduces the risk of cross-contamination, allowing high-purity media to be transported.
PP-H sheet lining
Tanks, which are already heavily attacked by chemical media, can be renovated with PP-H sheets of AGRU. The renovated tanks made of PP-H can withstand the strong influence of the present chemicals for a long time. Media: Hydrochloric acid (HCl), wastewater, temperature: up to 60°C