發(fā)布時(shí)間：2018-05-21 19:00

  本文選題：鎳基合金 + 單質(zhì)硫　； 參考：《西南石油大學(xué)》2017年碩士論文

【摘要】：鎳金合金由于其優(yōu)異的耐腐蝕性能而被廣泛地應(yīng)用于酸性油氣田,在酸性氣井的開(kāi)發(fā)過(guò)程中,由于元素硫的析出沉積會(huì)產(chǎn)生嚴(yán)重的局部腐蝕,使得鎳基合金在服役過(guò)程中經(jīng)受?chē)?yán)峻的考驗(yàn)。因此針對(duì)硫?qū)︽嚮辖鸬母g行為,研究硫沉積腐蝕發(fā)生的根本原因,正確認(rèn)識(shí)元素硫所引起的局部腐蝕機(jī)制是高含硫氣田開(kāi)發(fā)過(guò)程中必須要解決的問(wèn)題。本論文參照國(guó)內(nèi)外關(guān)于硫腐蝕研究成果,通過(guò)研究不同硫狀態(tài)下鎳基合金的腐蝕行為,探究高含硫環(huán)境下的腐蝕規(guī)律和局部腐蝕機(jī)制,以期為高含硫油氣生產(chǎn)輸送時(shí)的腐蝕與防護(hù)提供理論參考。本文首先對(duì)鎳基合金825在模擬不同溫度高含H2S/CO2及不同狀態(tài)單質(zhì)硫條件下的腐蝕規(guī)律以及腐蝕行為特征進(jìn)行了研究。結(jié)果表明,溫度和硫狀態(tài)是影響鎳基合金825腐蝕行為的重要因素;在溫度較低條件下,鎳基合金825的腐蝕輕微表現(xiàn)出均勻腐蝕的特征,隨著硫狀態(tài)的變化腐蝕速率發(fā)生小幅的增大;當(dāng)溫度升高到90℃時(shí),鎳基合金825的腐蝕速率升高,出現(xiàn)明顯的點(diǎn)蝕現(xiàn)象表現(xiàn)出局部腐蝕的特征;隨著腐蝕時(shí)間的延長(zhǎng),蝕坑逐漸增大,熔敷硫狀態(tài)下的合金尤為明顯,出現(xiàn)了晶間腐蝕裂紋。在溫度升高的條件下,腐蝕介質(zhì)中的硫的活性增大,鎳基合金825產(chǎn)物膜的穩(wěn)定性隨著溫度的升高而逐漸減弱,使得腐蝕速率逐漸增大。對(duì)高溫不同硫狀態(tài)條件下腐蝕后的鎳基合金825進(jìn)行X射線衍射(XRD)分析表明,在溫度較低的情況下,在無(wú)單質(zhì)硫條件和熔敷條件下產(chǎn)物膜主要是Cr203,而懸浮硫情況下由于硫的沉積使得基體表面出現(xiàn)了硫化物;當(dāng)溫度升高到90℃時(shí),在無(wú)單質(zhì)硫條件下產(chǎn)物膜成分仍為Cr203,但是衍射峰峰高降低,溫度升高使得產(chǎn)物膜穩(wěn)定性下降;在懸浮硫和熔敷硫條件下鎳基合金825腐蝕產(chǎn)物膜的結(jié)構(gòu)由硫化物和氧化物組成,膜層結(jié)構(gòu)由氧化物向硫化物的轉(zhuǎn)變,成為鎳基合金825腐蝕加深加重的主要原因,特別是熔敷硫條件下由常溫條件下的均勻腐蝕轉(zhuǎn)變成了局部腐蝕。其次,對(duì)在模擬不同溫度高含氏H2S/CO2及不同狀態(tài)單質(zhì)硫條件下腐蝕后的鎳基合金825進(jìn)行了極化曲線、交流阻抗測(cè)試及掃描電化學(xué)顯微鏡(SECM)測(cè)試,結(jié)果與宏觀腐蝕所得結(jié)果基本一致。極化曲線結(jié)果表明,在溫度升高及硫狀態(tài)變化的條件下,鎳基合金825表面自腐蝕電流密度隨之發(fā)生顯著增大,鈍化區(qū)間相應(yīng)變窄,由鈍化溶解逐漸轉(zhuǎn)化為活性溶解,鈍化膜穩(wěn)定性下降,保護(hù)性能變差。交流阻抗曲線的擬合結(jié)果也表明,在溫度升高及硫狀態(tài)變化的情況下,雙電層電容有升高的趨勢(shì),使得極化電阻減小,活性離子穿過(guò)鈍化膜所產(chǎn)生的阻力下降,保護(hù)性能降低,硫的加入使得合金表面穩(wěn)定性明顯減弱。SECM結(jié)果表明,在硫狀態(tài)變化和溫度升高的條件下,鎳基合金825基體表面的活性增強(qiáng),基體表面的電流峰峰高和峰頻增大,點(diǎn)蝕敏感性升高,抗腐蝕能力下降。最后,對(duì)鎳基合金825進(jìn)行了晶界工程處理,通過(guò)電子背散射衍射(EBSD)分析表明,退火后的鎳基合金825特殊角度晶界比例明顯提高。鎳基合金825特殊角度晶界∑3、∑9、∑27等隨機(jī)分布在一般大角度晶界構(gòu)成的晶界網(wǎng)絡(luò)上,破壞原有的晶界網(wǎng)絡(luò)的連通性,有效阻斷材料沿晶界的腐蝕開(kāi)裂以及其他失效形式的擴(kuò)展,從而使得鎳基合金825在高含硫環(huán)境下的抗腐蝕能力增強(qiáng)。通過(guò)極化曲線、交流阻抗曲線和掃描電化學(xué)顯微鏡分析發(fā)現(xiàn)晶界工程處理過(guò)后的鎳基合金825具有更好的耐蝕性和更低的點(diǎn)蝕敏感性。
[Abstract]:Nickel gold alloys are widely used in acid oil and gas fields because of their excellent corrosion resistance. In the process of developing acid gas wells, the precipitation of elemental sulfur will produce serious local corrosion, which makes nickel base alloys undergo severe tests during service. Therefore, the sulfur deposition of sulfur on nickel base alloys is studied. The root cause of corrosion and the correct understanding of the local corrosion mechanism caused by elemental sulfur are the problems that must be solved in the development of high sulfur gas fields. In this paper, the corrosion behavior of nickel based alloys under different sulfur States is studied by reference to the results of sulfur corrosion research at home and abroad, and the corrosion laws and local decay in high sulphur environment are explored. Corrosion mechanism is expected to provide a theoretical reference for corrosion and protection of high sulphur oil and gas production and transportation. The corrosion law and corrosion behavior characteristics of nickel base alloy 825 under the condition of simulating different temperatures and high H2S/CO2 and different state sulfur are studied. The results show that temperature and sulfur state are the 825 corrosion of nickel base alloy. Under the low temperature conditions, the corrosion of nickel base alloy 825 slightly showed the characteristic of uniform corrosion, and the corrosion rate increased slightly with the change of sulfur state. When the temperature rose to 90, the corrosion rate of the nickel base alloy 825 increased, and the obvious pitting phenomenon showed the characteristic of local corrosion. The corrosion crater increases gradually, and the alloy under the state of the deposited sulfur is particularly obvious, and the intergranular corrosion cracks appear. The sulfur activity in the corrosion medium increases with the temperature rising. The stability of the 825 product film of the nickel base alloy gradually decreases with the increase of temperature, which makes the corrosion rate increase gradually. The X ray diffraction (XRD) analysis of the nickel base alloy 825 after corrosion shows that under the condition of low temperature, the product film of the product is mainly Cr203 under the condition of no single sulfur and cladding, while the sulfur deposition makes the sulfide on the surface of the matrix under the condition of suspended sulfur, and when the temperature rises to 90, the product under the condition of no single sulfur is under the condition of the temperature rise. The composition of the membrane is still Cr203, but the peak height of the diffraction peak decreases and the temperature increases, the stability of the product film decreases. The structure of the 825 corrosion product film of the nickel base alloy is composed of sulfide and oxide under the suspended sulfur and the deposited sulfur, and the main reason for the aggravation of the 825 corrosion of the nickel base alloy is that the structure of the film is changed from oxide to sulfide. Second, the polarization curve, AC impedance test and scanning electrochemical micromirror (SECM) test are carried out for the nickel base alloy 825 after corrosion at different temperatures with high H2S/CO2 and different state elemental sulfur conditions, and the results are with macro corrosion. The results of polarization curves show that the corrosion current density of the 825 surface of Ni based alloy increases significantly at the temperature rise and the change of the sulfur state, and the passivation interval becomes narrower, and the passivation solution is gradually converted to active dissolution. The stability of the passivation film decreases and the protection performance becomes worse. The fitting result of the AC impedance curve is the result of the passivation film. It is also shown that in the case of temperature rise and the change of sulfur state, the electric double layer capacitance is rising, the polarization resistance decreases, the resistance of active ions passing through the passivation film decreases and the protection performance is reduced. The addition of sulfur makes the surface stability of the alloy weaken obviously.SECM results show that the condition of the change of sulfur state and the temperature increase. At the same time, the activity of the nickel base alloy 825 substrate was enhanced, the peak current peak and the peak frequency of the matrix increased, the pitting sensitivity increased and the corrosion resistance decreased. Finally, the nickel base alloy 825 was treated with grain boundary engineering. The EBSD analysis showed that the grain boundary ratio of the annealed nickel base alloy 825 was obviously improved. The 825 special angle grain boundary sigma 3, sigma 9, and sigma 27 of the nickel base alloy are randomly distributed on the grain boundary network formed by the general grain boundary, which destroys the connectivity of the original grain boundary network, effectively blocks the corrosion cracking along the grain boundary and the expansion of other failure forms, thereby increasing the corrosion resistance of nickel base alloy 825 in the high sulfur content environment. Strong. Through the polarization curve, AC impedance curve and scanning electrochemical microscopy, it was found that the nickel base alloy 825 after the grain boundary engineering treatment had better corrosion resistance and lower pitting sensitivity.
【學(xué)位授予單位】：西南石油大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TG178

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 劉振云;趙明;王學(xué)良;李建國(guó);;晶粒晶界對(duì)鋁合金耐蝕性能的影響[J];北京化工大學(xué)學(xué)報(bào)(自然科學(xué)版);2016年05期

2 王新印;夏妍;周亞茹;聶林林;曹發(fā)和;張鑒清;曹楚南;;基于掃描電化學(xué)顯微鏡產(chǎn)生/收集和反饋模式研究純Mg腐蝕行為[J];金屬學(xué)報(bào);2015年05期

3 李鈞;蘇誠(chéng);張磊;邵羽;肖學(xué)山;周志江;;晶界工程處理對(duì)Incoloy 800合金耐腐蝕性能和力學(xué)性能的影響[J];上海大學(xué)學(xué)報(bào)(自然科學(xué)版);2013年05期

4 范舟;李洪川;劉建儀;歐陽(yáng)旭;魯柳利;;高含硫氣田元素硫沉積及其腐蝕[J];天然氣工業(yè);2013年09期

5 關(guān)建慶;王樹(shù)濤;黃雪松;張慶生;鄭樹(shù)啟;陳長(zhǎng)風(fēng);;元素硫?qū)沽蛱坠茕揚(yáng)110SS腐蝕行為的影響[J];腐蝕與防護(hù);2013年08期

6 鄧洪達(dá);崔世華;李春福;曹獻(xiàn)龍;蘭偉;;鎳基合金G3在高含H_2S和CO_2環(huán)境中的腐蝕行為[J];腐蝕與防護(hù);2013年04期

7 李鈞;蘇誠(chéng);張磊;邵羽;肖學(xué)山;周志江;;Incoloy 800合金晶界工程工藝優(yōu)化研究[J];上海金屬;2013年01期

8 蔡曉文;戈磊;陳長(zhǎng)風(fēng);;元素硫沉積環(huán)境中P110鋼腐蝕特征的對(duì)比[J];材料科學(xué)與工程學(xué)報(bào);2012年06期

9 劉志德;路民旭;谷壇;張雷;閆靜;顧錫奎;霍紹全;韓丹丹;;高酸性氣田集輸系統(tǒng)元素硫存在條件下腐蝕影響因素[J];腐蝕與防護(hù);2012年S2期

10 魏先平;鄭文杰;宋志剛;雷霆;謝清程;易小東;;熱處理對(duì)Inconel718合金組織及力學(xué)性能的影響[J];材料熱處理學(xué)報(bào);2012年08期

相關(guān)博士學(xué)位論文 前1條

1 劉廷光;Fe-Cr-Ni合金的三維晶界網(wǎng)絡(luò)分布特征及其對(duì)應(yīng)力腐蝕開(kāi)裂擴(kuò)展路徑影響的研究[D];上海大學(xué);2015年

相關(guān)碩士學(xué)位論文 前1條

1 劉振云;鋁合金組織結(jié)構(gòu)對(duì)其耐蝕性能影響的研究[D];北方工業(yè)大學(xué);2016年

，

本文編號(hào)：1920373