Semi-Finished sheets PE 100, ECTFE and PFA

Daily a large number of transporters are on the road to meet the everincreasing demand on 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 costeffectiveness and product quality as well as a long service life.

Currently, most of tank containers are made of stainless steel. Depending on the application, these tanks have addi-tionally a thermoplastic lining (e.g. PE, ECTFE, PFA) in order to protect the steel from corrosion. An example for a currently PFA lined ISO steel container is shown in Figure 1. Due to the PE, ECTFE or PFA lining, these containers are showing an excellent chemical resistance. A negative aspect when talking about steel containers is the high weight, which is reducing the maximum loading capacity of the container, the law regulates this. Thus, the logistic partners are interested in a new solution to increase effectiveness.

 

Our Finnish customers, Oy Fluorotech Ltd and admor Composites OY were able to revolutionize the transportation industry by developing a lined fiberglass-reinforced plastic (FRP) container in an innovative way. Comparing the weight of a standard steel container with a FRP container, the FRP construction can achieve a weight reduction of approx. 1600 kg. Thus, it is possible to transport a larger amount of chemicals, whereby the efficiency is significantly increased. In order to achieve the required chemical resistance to the media, admor Composites OY uses the PE 100, ECTFE and PFA fabric backed semi-finished products 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, as well as 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.


Chemical resistance can be

ensured by plastic lining.


The container is made by a combination of FRP and thermoplastic lining material. By using this combination, the FRP takes over the static of the container. Due to the usage of a fabric backing system (see Figure 3) the thermoplastic lining material is fixed on the inner surface of the container, ensuring a perfect bonding. An example for a cross-section of a lined FRP laminate is shown in Figure 4.

How to make a FRP dual-laminate container

In the case of FRP composite constructions, the fabric backed sheet is first molded into the final shape by forming and welding. The fabric backing is located on the outside of the thermoplastic tank surface. Due to the low strength of the thin lining material, the tank shell is supported by a formwork from the inside. In the next step, FRP is applied onto the fabric backing side using the filament winding technology or hand lamination process. Next, the container is fixed on the ISO frame. In a final step the equipment (pumping station, safety valves etc.) is installed so that the container is fully operational. A completed ISO-FRP container with a PE 100 lining is shown in Figure 4 and Figure 5.
 

Conclusion and advantages of a PE-, ECTFE or PFA- lined FRP ISO container

  • By choosing a FRP dual laminate structure, the total weight of the container is significantly lower in comparison to a steel container (about 1600 kg). Due to the lower weight of the container, a larger amount of chemicals can be transported, whereby the efficiency is significantly increased.
  • The plastic lining (e.g. PE, ECTFE or PFA) ensures a long-term chemical resistance of the container.
  • Thermoplastic surfaces are very easy to clean compared to steel surfaces. In the case of a medium change, both the cleaning time and the required amount of cleaning media (water, aids) can be significantly reduced. In addition, the risk of contaminated media decreases.

     

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