输油管道腐蚀垢样中硫酸盐还原菌对Q235钢腐蚀行为的影响

摘要

取某输油管线腐蚀管垢进行硫酸盐还原菌(SRB)的富集培养,并测量SRB在生长周期内H2S含量变化趋势.采用腐蚀挂片和电化学试验研究了Q235钢在接种SRB溶液及无菌溶液中的腐蚀行为,并对腐蚀挂片表面形貌和产物进行了分析.结果表明:某输油管线中存在SRB,细菌代谢过程中产生了H2S气体,增加了管线钢硫化物应力腐蚀开裂的可能性;SRB导致Q235钢局部腐蚀严重,使得钢片表面腐蚀形式由轻微不非均匀腐蚀向严重局部腐蚀转变;SRB代谢产物主要为含硫化合物,这可能是诱发钢片局部腐蚀萌生的主要原因.%Sulfate reducing bacteria (SRB) from corrosion scale were cultured and the change trend of H2S from the solution with SRB in the growth cycle was measured to prove whether the existence of SRB was the cause of increasing sulfur content in the oil pipeline.Corrosion coupon test and electrochemical experiment were used to research the corrosion behavior of Q235 steel in SRB and sterile mediums and the corrosion morphology and products of the steel were alalyzed.The results showed that there existed SRB in the oil pipeline and hydrogen sulfide gas was produced in the process of metabolism,which increased the possibility of stress corrosion cracking of pipeline steel.The corrosion mode on the surface of the steel was changed from the slight non-uniform corrosion to serious localized corrosion due to SRB.The metabolites of SRB were mainly sulfur compounds,and might be responsible for the increase of localized corrosion of the steel.