本文選題：換熱器 + 失效分析�。� 參考：《浙江理工大學(xué)》2017年碩士論文

【摘要】：隨著原油對外依存度逐年攀升,我國大量進(jìn)口國外“高硫、高氮、含氯”的劣質(zhì)原油,導(dǎo)致加氫裝置中換熱器頻繁發(fā)生因NH_4Cl結(jié)晶而引發(fā)的流動腐蝕失效事故。鑒于NH_4Cl結(jié)晶沉積機理復(fù)雜,原油中的Cl、N含量波動幅度大,難以進(jìn)行準(zhǔn)確預(yù)測,嚴(yán)重影響煉油裝置的安穩(wěn)運行,因此亟需開展NH_4Cl結(jié)晶溫度預(yù)測方法及防控優(yōu)化方案研究。本文以JX石化加氫改質(zhì)裝置的換熱器失效為研究對象,進(jìn)行工藝關(guān)聯(lián)過程分析,明確加氫換熱器失效原因,開展NH_4Cl溶液垢下腐蝕實驗,揭示反應(yīng)流出物換熱器的銨鹽結(jié)晶機理,構(gòu)建NH_4Cl結(jié)晶溫度的預(yù)測模型。本文的主要結(jié)論如下:(1)基于加氫裝置運行工況,構(gòu)建工藝計算模型,分析換熱器E1103A/B中NH_4HS結(jié)晶和NH_4Cl結(jié)晶的失效風(fēng)險。通過工藝過程計算,確定NH_4Cl結(jié)晶溫度188℃,反應(yīng)流出物系統(tǒng)中不存在NH_4HS結(jié)晶,明確換熱器E1103A/B的主要失效原因為NH_4Cl的結(jié)晶沉積。同時分析四個影響因素對NH_4Cl結(jié)晶溫度的影響規(guī)律,明確影響NH_4Cl結(jié)晶溫度的主要因素為系統(tǒng)壓力、氯含量和氮含量。(2)針對加氫換熱器NH_4Cl結(jié)晶失效問題,采用恒溫恒濕試驗箱,開展四種典型石化材料的NH_4Cl溶液垢下腐蝕試驗研究,獲得不同環(huán)境溫度、溶液濃度對石化材料腐蝕速率的影響規(guī)律。通過掃描電鏡和能譜分析,獲得試件表面的腐蝕形貌和腐蝕產(chǎn)物的組成,揭示反應(yīng)流出物多相流體系中NH_4Cl結(jié)晶沉積的機理。(3)基于多相流體系工藝計算模型,采用最小二乘法,獲得獨立變量影響下NH_4Cl的結(jié)晶溫度變化函數(shù);根據(jù)NH_4Cl結(jié)晶溫度的變化規(guī)律數(shù)據(jù),采用偏最小二乘法,構(gòu)建包含氯含量、氮含量、壓力三個變量共同影響下的NH_4Cl結(jié)晶溫度預(yù)測模型。根據(jù)NH_4Cl結(jié)晶溫度的準(zhǔn)確預(yù)測,開展工藝注水位置及注水量的方案優(yōu)化。本文的創(chuàng)新之處在于:針對NH_4Cl形成機理復(fù)雜、結(jié)晶溫度預(yù)測困難的問題,通過對實際失效案例的分析,采用多相流工藝計算與偏最小二乘法相結(jié)合的方法,構(gòu)建了包含氯含量、氮含量、壓力三個關(guān)鍵影響因素下的NH_4Cl結(jié)晶溫度預(yù)測模型,實現(xiàn)了NH_4Cl結(jié)晶溫度的定量預(yù)測,提出了NH_4Cl結(jié)晶沉積的防控方法。研究成果可用于加氫換熱器NH_4Cl結(jié)晶沉積的風(fēng)險評估及防控優(yōu)化,確保加氫換熱器的長周期安全運行。
[Abstract]:With the increasing degree of external dependence of crude oil, China imports a large number of "high sulfur, high nitrogen, chlorine" crude oil, resulting in frequent heat exchangers in the hydrogenation unit caused by NH4Cl crystallization flow corrosion failure accident. In view of the complex mechanism of NH4Cl crystallization and deposition and the large fluctuation of ClN content in crude oil, it is difficult to predict accurately and seriously affect the stable operation of refining units. Therefore, it is urgent to study the prediction method of NH4Cl crystallization temperature and the optimization scheme of prevention and control. In this paper, the failure of heat exchanger in JX petrochemical hydrogenation upgrading plant is studied, the process correlation process is analyzed, the cause of failure of hydrogenation heat exchanger is determined, the scale corrosion experiment of NH4Cl solution is carried out, and the crystallization mechanism of ammonium salt in heat exchanger of reaction effluent is revealed. The prediction model of NH4Cl crystallization temperature was established. The main conclusions of this paper are as follows: (1) based on the operating conditions of the hydrogenation unit, the process calculation model is constructed, and the failure risk of NH4HS crystallization and NH4Cl crystallization in heat exchanger E1103A / B is analyzed. The crystallization temperature of NH _ 4Cl was determined at 188 鈩，

本文編號：2026333