流速对缓蚀剂成膜效率的影响

Study of Flow Rate on Corrosion Inhibitor Film Forming Efficiency

油气集输管道因输送的介质中含有腐蚀性气体和离子等成分,会造成严重的管道内腐蚀。缓蚀剂技术因其经济可靠和操作方便,在管道防腐工程中被广泛使用,但管道内流体的流速对缓蚀剂的成膜性能和缓蚀效率具有极大的影响。利用自主研制的动态循环多相流高温高压釜和电化学方法 (电化学阻抗谱、动电位极化)研究了有机胺缓蚀剂对五组试样在不同流速(1、3、5、7、10 m/s)下的缓蚀性能。结果表明,随着流速的增加,缓蚀效率逐步降低,当流速大于7 m/s时,缓蚀效率会明显降低。高速流体的剪切作用降低了缓蚀剂在管道表面的吸附性能,并且试样表面的腐蚀产物膜疏松多孔,易产生点蚀,缓蚀剂的效果显著下降,建议控制流体流速和开发多位点吸附的新型缓蚀剂。

Oil and gas pipelines are suffering from serious inter- corrosion due to the pumped medium containing a large of corrosive gas and salts. Corrosion inhibitor is widely used in the anticorrosion engineering of oil and gas pipelines because of its low- cost and its simplicity of operation. However, the flow rate has a great effect on corrosion inhibitor film forming properties and corrosion inhibition efficiency. In this paper, home- made dynamic multiphase flow autoclave and electrochemical methods（EIS, potentiodynamic polarization）were used to study the influence of different flow rate（1,3,5,7,10 m/s） on the corrosion inhibition efficiency. The results show that inhibition efficiency decreased with the increasing of flow rate.When the flow rate exceeded 7 m/s,the corrosion inhibition efficiency reduced significantly.High-speed fluid shear reduces the adsorption layer of corrosion inhibitor on the pipeline surface, causing porous corrosion films and pitting corrosion. Based on these results, controlling the fluid flow rate and developing the new corrosion inhibitor with polyadorption group are recommended.