Integrity study of liquefied petroleum gas in petrochemical industries due to corrosion and settlement

Abstract

Liquefied petroleum gas (LPG) is used as a fuel and intermediate product for petrochemical manufacturing. For storage and transportation, usual LPG tanks will be sealed and pressurized to eliminate the potential evaporative emissions and spillage. However, if there is a leakage, the probability on developing corrosion at the tank’s floor either internally or externally, will cause potential hazardous condition. Corrosion is the destructive attack on a substance, usually metal due to the interaction of chemical or electrochemical reaction with the environment Even though the failure or leakage of storage tanks may not disturb the normal operations but it may have serious impact on economic and environment. Tank floor failures due to corrosion process are dangerous because the leakage would penetrate into the ground for years before it been detected. It has been estimated to a loss of USD 5.5 billion per year due to the corrosion on the storages (NACE, 1984). External corrosion can be categorized as pitting corrosion, bimetallic corrosion and corrosion caused by water trap. It is very difficult to detect on when and where the corrosion has been set off as the ultrasonic measurements on plates which are irregularly corroded underneath may not give accurate results, and the inspected area is generally too large to be covered by a single probe.