Abstract
Components used in chemical plants are exposed to extreme stresses due to process conditions. Aggressive media, pressure differences and marked changes in temperature require corrosion protection systems combining high chemical resistance, good mechanical strength and high thermal stability to insure permanently reliable plant operation. Conventional metal equipment and pipe work systems often fail to meet expectations for lasting reliability.
For many decades now, glass fiber-reinforced unsaturated polyester and vinylester resins (FRP) have been a familiar and highly appreciated alternative to metal materials. With their chemical-resistant layer and thermoplastic liner they offer good corrosion resistance and are thus ideal materials for equipment and pipe work construction. Up to the 1990s, the media usually handled and stored were aqueous liquids, so that materials with dimensional stability of up to 125°C were adequate. Since then, increasing use has been made of plastic components, especially in constructing equipment and plant components exposed to high thermal stresses in chemical process engineering. Consequently, the demand for higher thermal and chemical stability of the construction materials has increased as well. The product found to meet such demands is a composite system comprising a load-bearing FRP layer and, firmly bonded to it, a modified polytetrafluoroethylene liner. This paper outlines the development of this relatively new composite material. It also describes the practical experience the chemical process engineering industry has gained with this material. Such experience relates in particular to demanding applications combining both aggressive media and high temperatures.
