The transport of strong acids, caustics and other corrosive media including diverse organic compounds require pipeline material solutions, which stand the significant corrosive load and behave good-natured in terms of operating expenditure. Although a number of good-working metal and lined metal pipe solutions are established in the market, they can suffer technical problems under certain circumstances. Problems for example can be leakages in the flange regions, material loss due to surface corrosion from the inside (unlined metal pipes) or media-permeation caused problems (lined steel pipes), the latter for example with chlorine and hydrochloric acid.
Here, FRP (fibre reinforced plastics) - reinforced liner pipes from melt-extruded fluoropolymers offer an excellent technical alternative, as already demonstrated in numerous successful applications. The pipe segments can be connected by welding, and the number of flanges thus reduced drastically. The inert nature of the inner liner pipes rule out surface degradation from the inside, given that the materials had been chosen appropriately. The relatively permeable outer FRP layer with its very good emergency running properties reduces failures caused by media permeation significantly (principle permeation-tightest layer inside fulfilled). Lightweight construction, outstanding cleaning properties and a reduced pressure loss are further benefits.
A principle introduction of the polymers (partially and fully fluorinated) will be conducted, also in comparison to the sintered polytetrafluoroethylene (PTFE), and application ranges will be demonstrated. The manufacturing and installation methods including best practices will be explained. Examples under various process conditions and from various processes will be shown. The latter will include a recent case study, in which an over-sized FEP (tetrafluoroethylene-hexafluoropropylene) liner pipe reinforced with vinylester FRP is used for the transport of hot sulphuric acid fume, produced in metallurgy.