液化石油气中硫化物对铜腐蚀的影响及机理研究

The effect and mechanism of copper corrosion by sulfurcontaining compounds in liquefied petroleum gas

液化石油气(LPG)中极少量的硫化物会对铜质设备造成严重的腐蚀,影响LPG的生产、销售和使用,因此研究LPG中硫化物对铜腐蚀的影响具有重要的实际意义。研究了LPG中不同含量的羰基硫、乙硫醇及硫化氢对铜片腐蚀的影响,并通过扫描电子显微镜(SEM)、能谱仪(EDS)和全反射红外光谱法(ATR)对腐蚀产物进行了表征和分析,探究了这3种硫化物对铜片腐蚀的机理。结果表明,当LPG中羰基硫和乙硫醇的含量为20μg/g时开始腐蚀铜片,硫化氢的含量为5μg/g时开始腐蚀铜片,随着硫化氢含量的增加,腐蚀程度加剧;当3种硫化物的含量为20μg/g时,铜片均出现明显的腐蚀产物,腐蚀以局部腐蚀为主。羰基硫和乙硫醇的腐蚀产物中含有机化合物成分,硫化氢的腐蚀产物主要为无机物Cu_(2) S和Cu_(2)O;羰基硫对铜的腐蚀过程为铜原子与羰基硫中的硫和碳成键,形成羰基硫化铜,或者铜原子与硫成键,形成缔合后的复杂腐蚀产物。

A very small amount of sulfur-containing compounds in liquefied petroleum gas(LPG)can cause serious corrosion of copper equipment and affect the production,sales and use of LPG.Therefore,it is of great practical significance to study the effect of sulfurcontaining compounds in LPG on copper corrosion.This work studies the effects of different contents of carbonyl sulfide,ethyl mercaptan and hydrogen sulfide in LPG on the corrosion of copper sheets.The corrosion products were characterized and analyzed by scanning electron microscopy(SEM),energy spectrometry(EDS)and attenuated total reflection infrared spectroscopy(ATR).The corrosion mechanisms of the three sulfurcontaining compounds on copper sheets were explored.The results showed when the content of carbonyl sulfide and ethyl mercaptan in LPG is 20μg/g,it starts to corrode copper flakes.When the content of hydrogen sulfide is 5μg/g,the copper flakes begin to corrode.As the content of hydrogen sulfide increases,the degree of corrosion increases.When the content of the three sulfurcontaining compounds is 20μg/g,obvious corrosion products appear on copper sheets,and the corrosion is mainly localized.The corrosion products with carbonyl sulfide and ethyl mercaptan contain organic moieties,and the corrosion products with hydrogen sulfide are mainly inorganic Cu_(2) S and Cu_(2)O.The corrosion process of carbonyl sulfide with copper is that copper atoms bond with sulfur and carbon in carbonyl sulfide to form copper carbonyl sulfide,or copper atoms bond with sulfur to form complex corrosion products after association.