The Types and Relationship to Copper Strip Corrosion of Sulfides in LPG

Liquefied Petroleum Gas (LPG) just like Liquefied Natural Gas (LNG) can be used as fuel for domestic and commercial purposes like town gas and auto gas. Although the caustic sulfur components derived from Fluidized Catalytic Cracking (FCC) processing in LPG have been removed before the LPG is transported into tanks, sometimes the case converted the result of copper strip corrosion test from passing to failing still happened when the LPG were stored in tanks for several days in some refineries. In order to find out which kind of sulfide components are the resource of corrosion, the sulfur species in LPG batches that passed and failed in copper strip corrosion test had been analyzed by using Gas Chromatography coupled with Flame Photometric Detector (GC-FPD), and the conversion law among the different sulfide components was discovered. From the study results, it can be found that the hydrogen sulfide and Methanethiol in LPG cause LPG to fail the copper strip corrosion test, and they are derived from dimethyl disulfide Ο, which is the main sulfur compound in LPG. The higher the temperature is, the more concentrations of Hydrogen sulfide and Methanethiol derived from DMDS are.