FLUORO POLYMER LINED PIPELINES

General Specification

Fluoropolymers are used in the chemical processing industry principally for outstanding resistance to almost all chemicals their ability to withstand high temperatures also plays an important part in their functional role. The low mechanical Properties and high permeation rates of fluoropolymers at high temperature limit their use of linings to about 175 Degree Celsius, although they remain chemical inert up to 260 Degree Celsius.

Selection of polymers is an integral part of the overall material selection process. This implies that all the available material such as metals, ceramics and plastics are considered candidates for an application. The End user then considers these materials against established criteria such as required life, mean time between inspection, ease of fabrication, frequency of inspection ,extent of maintenance and capital cost.

More often than not it is the initial capital cost rather than life cycle cost of the equipment that affects the decision made during the material selection step. However the most important piece of data in the medium under consideration over the life of the equipment.

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PTFE/FEP/PFA Specifications

Liner type Specification Properties
Virgin PTFE paste extruded ASTM D4895 Minimum Tensile Strength : 20.7MPa
Minimum Elongation of break : 200 to 300 %
Specific Gravity : 2.14-2.18 (when tested to ASTM D792 or D1505)
Static dissipating PTFE Paste Extruded ASTM D4895 Minimum Tensile Strength : 20.7MPa
Minimum Elongation of break : 200 to 300 %
Specific Gravity : 2.14-2.18 (when tested to ASTM D792 or D1505)
Virgin FEP ASTM D 2116 Minimum Tensile Strength : 20.7 MPa
Minimum Elongation of break : 250%
Specific gravity : 2.18
Virgin PFA ASTM D3307 Minimum Tensile Strength : 26.2 MPa
Minimum Elongation of break : 300%
Specific Gravity : 2.12 – 2.17 (when tested to ASTM D792 or D1505)
Melt flow rate : 1-2.5 g/10mins ( when tested to ASTM D3307 at 3720 C)
Static Dissipating PFA ASTM D3307 Minimum Tensile Strength : 26.2 MPa
Minimum Elongation of break : 300%
Specific Gravity : 2.14-2.17 (when tested to ASTM D792 or D1505)
Melt flow rate : 1-2.5 g/10mins ( when tested to ASTM D3307 at 3720 C)

Technical Guideline

Fluoropolymer Basics

The Chemical Process Industries (CPI) face many challenges in the containment of highly corrosive products and intermediates, both in processing facilities and in the treatment of process wastes. Often the combination of temperatures and pressures severely limits the service life of conventional systems. Successful containment needs to be cost effective, safe and environmentally responsible.

These requirements create the need for more corrosion resistant equipment and piping suitable not only for aggressive individual chemicals, but also for multi-component mixtures, whose compositions may vary with time and over a wide range of pH. Historically, metals have been used to solve most corrosion problems, however, some current process conditions exceed the capabilities of even the most expensive and exotic metals.

As an alternative, fluoropolymers can provide successful containment facilities in many cases.Fluoropolymers are highly corrosion resistant to a wider range of chemicals at varying concentrations and pH’s.