To provide additional passivation to the tin plate, it is dipped into a hot bath of concentrated chromic acid. Due to the highly corrosive nature of the liquid, it is essential to provide adequate corrosion protection for the bath and other plant components. In the past, rubber like flexible linings were used, which faced delamination problems, reducing the equipment's lifetime.
AGRU engineers confidently convinced the end customer that PVDF is the most suitable material for this application. Its excellent chemical resistance to chromic acid, even at high temperatures, makes it the ideal choice. When combined with the polyester fabric backing system (PGW), it allows for a fully bonded lining to the tank, ensuring a long and reliable service life. The parts in direct contact with Chromic acid were lined with 4.0 mm PVDF PGW sheet material. To ensure that acid vapors do not attack the outside of the steel structure, the outside surfaces of the tanks were lined using 3 mm PVDF sheets. In total, approximately 300 m² of AGRU PVDF GWP sheets were installed by Pennwalt.
Agru thanks all involved companies, and especially Pennwalt, for their excellent cooperation.
End-Customer: Tata Tin Plate Jashedpur
Fabricator: Pennwalt Pvt Ltd.
Year of installation: 2023
Material: PVDF sheets fabric backed 3 mm and 4 mm
Medium: Chromic acid
Side view of the components showing the corrosion protection lining on the inside and the outside
Dipping bath lined with PVDF