Plastics are highly resistant to corrosion because they are non-metallic and so there is no galvanic (electrochemical), aerobic, pitting and inter-granular corrosion mechanisms possible with plastics. But plastics alone cannot be used for many load applications like tanks and vessels because their low strength and modulus property which is more pronounced at high temperatures (say, above 60 degrees). So technology of reinforcing plastics with fibres of high strength and stiffness evolved and perfected. FRP are plastics reinforced with stiff and strong glass fibres. Now FRP is considered as new generation construction material for chemical process plant equipments.
Fibreglass resists a wide range of chemicals and temperatures, but it requires the right design, fabrication and installation to match the appropriate application.
Several resin systems suitable for various specific corrosion conditions are available. Glass fibre is available as Chopped Strand Mat, Woven Roving, Roving and Surface Veils. A simple fabrication method namely hand layup is still the most preferred method for manufacturing for Chemical Plant Equipments. Filament winding is done wherever additional load bearing requirements can be economically met. Dual laminates are more in use now and are FRP equipments with thermoplastic corrosion resistant process face of - PP, PVC, ECTFE, FEP, PVDF, etc., i.e. a thermoplastic chemical barrier lining which is bonded to FRP structure. Simply it is a combination of excellent chemical resistance of thermoplastics and moderate mechanical properties of FRP.
Corrosion resistance, moderate strength and ease of fabrication make composites, particularly glass reinforced plastics, admirably suitable for process plant applications. Large, complex GRP components are readily produced in small quantities and the installed cost of GRP plant is highly competitive with that manufactured from other more traditional materials, e.g. stainless steel, rubber-lined steels, etc. Storage tanks, pressure vessels, pipe work, stacks and ducting systems are available from a number of organizations and there are numerous examples of successful operations over many years.
Composites are extensively used in industrial gratings, structural supports, storage tanks, scrubbers, ducting, piping, exhaust stacks, pumps & blowers, columns, reactors etc. for acidic & alkaline environments. Some of the potential applications are:
- Semiconductor Manufacturing Industry
- Metal Finishing / Electroplating Industry
- Chemical Manufacturing / Processing Plants
- Bulk Drugs Manufacturing / Pharmaceutical Industry
- Sewage Treatment Plants
- Steel Mills
- Pulp & Paper Mills
- Thermal Power Plants
- Fertilizer / Pesticide Industry
- Dyes & Intermediate Industry