FRP Works ( Tank, Piping and Lining )
FRP (Fibreglass Reinforced Plastics, also known as GRP, or Glass Reinforced Plastics) is a modern compositematerial of construction for chemical plant equipment like tanks and vessels. Chemical equipment that range in size from less than a metre to 20 metres are fabricated using FRP as material of construction.
FRP Chemical Equipments are manufactured mainly by Hand Lay-up and filament winding processes
Due to the corrosion resistant nature of FRP, the tank can be made entirely from the composite, or a second liner can be used. In either case, the inner liner is made using different material properties than the structural portion (Hence the name dual (meaning two) and laminate (a word commonly used for a layer of a composite material))
The liner, if made of FRP is usually resin rich and utilizes a different type of glass, called “C-Glass”, while the structural portion uses “E-Glass”. The thermoplastic liner is usually 2.3 mm thick (100 mils). This thermoplastic liner is not considered to contribute mechanical strength. The FRP liner is usually cured before winding or lay-up continues, by using either a BPO/DMA system, or using an MEKP catalyst with cobalt in the resin.
If the liner is not made of FRP, there are multiple choices for a thermoplastic liner. The engineer will need to design the tank based on the chemical corrosion requirement of the equipment. PP, PVC, PTFE, ECTFE, ETFE, FEP, CPVC, PVDF are used as common thermoplastic liners.
Due to FRP’s weakness to buckling, but immense strength against tensile forces and its resistance to corrosion, a hydrostatic tank is a logical application for the composite. The tank is designed to withstand the hydrostatic forces required by orienting the fibres in the tangential direction. This increases the hoop strength, making the tanks anisotropically stronger than steel (pound per pound).
FRP which is constructed over the liner provides the structural strength requirements to withstand design conditions such as internal pressure or vacuum, hydrostatic loads, seismic loads (including fluid sloshing), wind loads, regeneration hydrostatic loads, and even snow loads.