【摘要】：煉油裝置酸水系統(tǒng)沖蝕是原油劣質(zhì)化、裝置大型化、運(yùn)行工況苛刻化發(fā)展過程中普遍存在的失效形式。特別是隨著高硫、高酸、含氯等劣質(zhì)原油加工比例的增加，酸水處理系統(tǒng)的流動(dòng)腐蝕失效問題極為突出，嚴(yán)重威脅裝置的長周期運(yùn)行。針對(duì)酸水系統(tǒng)頻繁出現(xiàn)流動(dòng)腐蝕失效的現(xiàn)象，如何揭示其內(nèi)在的失效機(jī)制并建立定量的失效預(yù)測方法，一直是學(xué)術(shù)界和工程界關(guān)注的焦點(diǎn)之一。 本文以酸水汽提塔頂空冷出口管道的失效為研究對(duì)象，運(yùn)用解剖分析、工藝模擬、流動(dòng)狀態(tài)計(jì)算相結(jié)合的研究方法，分析管件失效形貌，獲得空冷器出口管道內(nèi)多相流物性參數(shù)及腐蝕性介質(zhì)的平衡分布規(guī)律，結(jié)合流動(dòng)狀態(tài)揭示空冷器出口管道系統(tǒng)沖蝕失效機(jī)理；針對(duì)酸水系統(tǒng)的腐蝕性介質(zhì)組成，配制多相流腐蝕性介質(zhì)，運(yùn)用旋轉(zhuǎn)式?jīng)_蝕實(shí)驗(yàn)裝置采用Tafel極化曲線和SEM形貌分析法開展典型管材碳鋼沖蝕規(guī)律研究，測試獲得了NH4HS濃度、溫度、H2S分壓、氯離子含量及壁面剪切應(yīng)力影響因素下碳鋼的腐蝕產(chǎn)物膜特性及沖蝕特性，形成沖蝕實(shí)驗(yàn)數(shù)據(jù)庫；結(jié)合沖蝕實(shí)驗(yàn)數(shù)據(jù)庫，基于BP神經(jīng)網(wǎng)絡(luò)構(gòu)建酸水系統(tǒng)的沖蝕速率預(yù)測模型，實(shí)現(xiàn)對(duì)酸水系統(tǒng)沖蝕速率的準(zhǔn)確預(yù)測。研究結(jié)果表明：1）典型工況下空冷出口管道系統(tǒng)的NH4HS濃度高，流速快是引發(fā)管壁沖蝕減薄的主要原因；2）出口管道配置不平衡使多相流分布不均造成彎頭外側(cè)及上游內(nèi)側(cè)局部腐蝕嚴(yán)重，腐蝕性介質(zhì)以不連續(xù)液膜形式流動(dòng)，使得壁面腐蝕形貌為坑蝕；3）碳鋼的沖蝕速率受腐蝕反應(yīng)及腐蝕介質(zhì)擴(kuò)散雙重因素的影響；4）腐蝕產(chǎn)物膜疏松、表面多孔、粘結(jié)性差使得壁面剪切應(yīng)力高于特定值時(shí)，產(chǎn)物膜脫離材質(zhì)基體而失去保護(hù)作用；5）采用沖蝕預(yù)測模型對(duì)已有實(shí)驗(yàn)結(jié)果進(jìn)行預(yù)測，，平均誤差在8.63%以內(nèi)，沖蝕模型預(yù)測精度高，可推廣應(yīng)用于其它條件下碳鋼管材腐蝕速率預(yù)測。 本文的創(chuàng)新之處在于：1）運(yùn)用解剖分析、工藝仿真、流動(dòng)狀態(tài)計(jì)算手段，確定酸水系統(tǒng)沖蝕失效機(jī)理；2）結(jié)合產(chǎn)物膜特性和沖蝕特性研究，分析不同影響因素下沖蝕規(guī)律的內(nèi)在影響機(jī)制；3）基于BP神經(jīng)網(wǎng)絡(luò)建立了酸水系統(tǒng)沖蝕預(yù)測模型。
[Abstract]:The erosion of acid water system in oil refining unit is a common failure form in the development process of crude oil deterioration, large-scale plant and harsh operation conditions. Especially with the increase of the processing proportion of crude oil with high sulfur, high acid and chlorine content, the flow corrosion failure of the acid water treatment system is very prominent, which seriously threatens the long period operation of the plant. In view of the frequent flow corrosion failure of acid water system, how to reveal its internal failure mechanism and establish a quantitative failure prediction method has been one of the focuses of academic and engineering circles. In this paper, the failure of the air-cooled outlet pipe at the top of the acid water stripping tower is studied. The failure morphology of the pipe is analyzed by using the methods of anatomical analysis, process simulation and flow state calculation. The physical parameters of multiphase flow and the equilibrium distribution of corrosive media in the outlet pipeline of air cooler are obtained. Combined with the flow state, the erosion failure mechanism of air cooler outlet pipeline system is revealed, and the corrosive medium composition of acid water system is discussed. The corrosive medium of multiphase flow was prepared. The erosion law of typical carbon steel was studied by means of Tafel polarization curve and SEM morphology analysis method. The concentration of NH4HS and the partial pressure of H _ 2S were obtained by measuring the concentration of NH4HS, the temperature and the partial pressure of H _ 2S. Under the influence of chloride ion content and wall shear stress, the corrosion product film and erosion characteristics of carbon steel are formed, the erosion experiment database is formed, the erosion rate prediction model of acid water system is constructed based on BP neural network, and the erosion experiment database is combined with the erosion experiment database. The erosion rate of acid water system can be predicted accurately. The results show that the NH4HS concentration of the air-cooled outlet pipeline system is high under typical operating conditions and the high velocity of flow is the main reason for the erosion thinning of the pipe wall. 2) the uneven distribution of the multiphase flow in the outlet leads to serious corrosion on the outside of the elbow and the inner side of the elbow, and the corrosive medium flows in the form of discontinuous liquid film, which makes the corrosion appearance of the wall as pit corrosion; 3) the erosion rate of carbon steel is affected by the double factors of corrosion reaction and corrosion medium diffusion. 4) when the corrosion product film is loose, the surface is porous, and the adhesion is poor, the wall shear stress is higher than the specific value. The erosion prediction model is used to predict the experimental results. The average error is less than 8.63%, and the prediction accuracy of the erosion model is high. It can be applied to predict corrosion rate of carbon steel pipes under other conditions. The innovation of this paper lies in the application of anatomical analysis, process simulation and flow state calculation to determine the erosion failure mechanism of acid-water system. Based on BP neural network, the erosion prediction model of acid-water system is established.
【學(xué)位授予單位】：浙江理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TE986

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 鄭玉貴,姚治銘,龍康,李生春,柯偉;液/固雙相流沖刷腐蝕實(shí)驗(yàn)裝置的研制及動(dòng)態(tài)電化學(xué)測試[J];腐蝕科學(xué)與防護(hù)技術(shù);1993年04期

2 李曉剛,付冬梅,董超芳,金鷹;用神經(jīng)網(wǎng)絡(luò)算法分析環(huán)烷酸的腐蝕行為[J];腐蝕科學(xué)與防護(hù)技術(shù);2001年01期

3 孔濤;王佳;鐘蓮;;組合人工神經(jīng)網(wǎng)絡(luò)模型預(yù)測海水腐蝕速度的研究[J];腐蝕科學(xué)與防護(hù)技術(shù);2008年01期

4 姜?jiǎng)倮?鄭玉貴;喬巖欣;陳世鐸;;高速噴射式?jīng)_刷腐蝕實(shí)驗(yàn)裝置的研制及其實(shí)時(shí)動(dòng)態(tài)電化學(xué)測試[J];腐蝕科學(xué)與防護(hù)技術(shù);2009年05期

5 趙景茂;魏輝榮;張嬌嬌;熊金平;唐聿明;左禹;;L360鋼在H_2S/CO_2環(huán)境中腐蝕的預(yù)測[J];腐蝕科學(xué)與防護(hù)技術(shù);2012年02期

6 苗世蕾;艾景輝;;石化空冷器的防腐蝕技術(shù)評(píng)述[J];腐蝕與防護(hù);2008年06期

7 楊凌;卜文海;高立群;李環(huán)宇;;BP神經(jīng)網(wǎng)絡(luò)預(yù)測碳鋼在油田水介質(zhì)中的腐蝕速率[J];腐蝕與防護(hù);2008年10期

8 劉忠;劉春波;鄭玉貴;;碳鋼在單相流中流動(dòng)加速腐蝕的數(shù)值模擬[J];核動(dòng)力工程;2009年05期

9 偶國富;曹海彬;朱祖超;王艷萍;包金哲;;加氫含硫污水管道沖蝕臨界特性的電化學(xué)測試[J];化工學(xué)報(bào);2009年03期

10 金浩哲;偶國富;李鵬軒;;基于相似理論的REAC出口彎管沖蝕瞬態(tài)特性[J];化工學(xué)報(bào);2011年S2期

本文編號(hào)：2239881