EXPERIENCES IN THE USE OF POLYMERS FOR THE PREVENTION ANE' CONTROL OF CORROSION IN THE VENEZUELAN PETROCHEMICAL INDUSTRY

摘要

Polymeric materials (thermoplastics, thermoses and elastomers) have excellent chemical resistance at low temperatures in a diversity of corrosive industrial environments and when they are fiber reinforced have strong mechanical properties. They have competitive costs, low weight and they are easy to install. For these reasons, their use increased in major projects in Venezuelan Petrochemical Industry between 1988 and 1992. This paper summarizes three experiences with some polymers used at our Chlorine-Alkali Plant: 1) Caustic stress cracking of PVDF anolyte piping and PVDF disc valve linings 2) Use of dual laminated FRP/ETFE composite to replace the original design of two chlorine neutralizing tanks made of steel and brick-mortar lining, which failed prematurely 3) Failures of FRP piping due :o concentrated sulphuric acid attack in the chlorine drying tower circuit. In each case, polymer failures were related to a marginal material selection and to an occasional inadequate operation. None of them were caused by the polymer itself. On the contrary, changing traditional materials to appropriate polymers has improved the service factor, the reliability and the operation of the process plant.