932石油加工)0卷 石油学报( 第3
-#
的N碳2.3 含不同质量浓度ClHS溶液中104H
钢的腐蚀规律
目前,世界原油中的氯质量浓度一般在0.5~/15mL范围,加氢反应流出物的含硫污水中一般g
--
/。C具有一定的侵蚀性,含有1~200mL的Cllg
]1213-。在能增加腐蚀性溶液对金属材料的腐蚀速率[
-
质量浓度的520℃、不同Cl.0%NH4HS溶液中,
#
碳钢腐蚀速率随流速的变化示于图7。10
-
/)由图7可见,低流速(下,C与v<3.5msl#
碳钢的腐腐蚀产物膜的反应主要由扩散控制,10-
蚀速率随v的增加而迅速增加,C质量浓度不超l-#
/过1碳钢的腐蚀速率随C质量浓00mL时,10lg
/150mL时,腐蚀产物膜的坑蚀孔径已增大至g
#
碳钢金属基体保护性能显著降20~30μm,对10
-
低。另外,由于C半径小,具有较强的穿透能力,l
易穿过腐蚀产物膜内极小的间隙与金属基体互相作用,形成可溶性氯化物,弱化金属与腐蚀产物间的附着力,使得腐蚀产物膜更易脱落。
/度的变化并不明显。当v≥3.5ms时,扩散传质的
-#
影响逐渐被削弱,相同C浓度下1碳钢的腐蚀l0
速率随v的进一步增加基本保持不变;但是随着
-
质量浓度的增加,1Cl0#碳钢的腐蚀速率升高。
-图8为不同C质量浓度的5%NH4HlS溶液中-
与难溶性腐蚀产物10碳钢的SEM照片。由于Cl
发生反应,生成可溶性氯化物,使腐蚀产物膜发生#
-
图7 含不同质量浓度C的NlHS溶液中10#碳钢腐蚀4H
)的变化速率随流速(v()Fi.7 Corrosionrateof10#carbonsteelvsvelocitiesvin g
-
SsolutionwithdifferentmassconcentrationsofClNH 4H
坑蚀现象
[14]
-
。由图8可见,腐蚀产物表面膜因Cl
-
/的侵蚀而成蜂窝状,C质量浓度为5l0mL时,g-
腐蚀产物间布有3~6μ质量浓度增至m的孔隙,Cl
)w(NH4HS=5.0%;0℃θ=2
-)(/(·L-1):())))cClm10;(250;(3100;(4150g
-
图8 在不同C质量浓度的NlHS溶液中腐蚀后的10#碳钢的SEM照片4H
Fi.8 SEMhotosofthecorroded10#carbonsteelsurfaceinNHSsolutionwith 4Hgp
-
differentmassconcentrationsofCl
)w(NH4HS=5.0%;0℃;θ=2
-)(/(·L-1):()))cClma0;(b50;(c150g
3 结 论
#
()在5碳1.0%质量分数NH4HS溶液中,10
()在52.0%质量分数NH4HS溶液中,温度为
#
/碳钢的腐40℃、腐蚀介质流速v<1.2ms时,10
蚀速率随v的增加而明显增加;温度为60℃时,腐蚀速率不再受v的影响,温度成为影响腐蚀速率的关键因素。温度升高造成腐蚀产物膜致密性与黏结性能降低,是10#碳钢腐蚀速率随温度升高而迅速增加的主要原因。
钢表面会形成致密的腐蚀产物膜,对材料起保护作用;随溶液中NH4HS质量分数的增加,腐蚀产物
#
膜出现龟裂和产物膜疏松现象,造成1碳钢在冲0
刷条件下腐蚀速率迅速增加。
第5期 0#碳钢在NH4HS溶液中的冲蚀规律 1933
(3)腐蚀产物膜受Cl
-
侵蚀而成蜂窝状,降低了其对10#
碳钢基体的保护能力;v>3.5m/s时,10#
碳钢的腐蚀速率随腐蚀介质中Cl-质量浓度的增加而迅速升高。
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