本文選題：腐蝕 + 汽水系統(tǒng)��； 參考：《華北電力大學(xué)》2014年碩士論文

【摘要】：隨著環(huán)境問(wèn)題的日益突出,提高燃煤機(jī)組的經(jīng)濟(jì)效率,降低燃煤機(jī)組的污染物排放量成為燃煤機(jī)組的主要問(wèn)題。目前,高參數(shù),大容量的機(jī)組因其高經(jīng)濟(jì)性越發(fā)受到各界重視。但機(jī)組蒸汽參數(shù)的不斷提高也增大了汽水系統(tǒng)腐蝕風(fēng)險(xiǎn),使得熱力管道受熱面安全管理面臨更大的挑戰(zhàn)。 本文主要針對(duì)汽水腐蝕產(chǎn)物遷徙問(wèn)題,通過(guò)理論分析和計(jì)算分析得出影響汽水系統(tǒng)腐蝕產(chǎn)物生成和遷徙的因素。定性分析了不同參數(shù)對(duì)腐蝕產(chǎn)物遷徙的影響,還結(jié)合了電廠實(shí)際運(yùn)行數(shù)據(jù)來(lái)研究腐蝕產(chǎn)物的遷徙過(guò)程。 電廠汽水系統(tǒng)中腐蝕產(chǎn)物的產(chǎn)生部分主要是低溫部分的流動(dòng)加速腐蝕以及高溫部分金屬腐蝕。流動(dòng)加速腐蝕主要是碳鋼表面保護(hù)性的磁鐵礦層(Fe304)在(單相)流動(dòng)的水或是(兩相)濕蒸汽中溶解的過(guò)程。金屬高溫腐蝕主要是超臨界水或者是高溫蒸汽和金屬基體發(fā)生氧化反應(yīng),一般情況下生成Fe304和FeCr2O4組成的雙層氧化層。 在汽水系統(tǒng)中腐蝕產(chǎn)物主要有：Fe3O4、Fe(OH)2、α-Fe2O3、Fe2+、γ-Fe2O3、 Fe(OH)2+、Fe(OH)4-、Fe3+、Fe(OH)3等。根據(jù)E-pH圖可以判斷出,在汽水系統(tǒng)中最重要腐蝕產(chǎn)物是Fe2+,在所有E-pH圖中固體-液體界面中都存在Fe-Fe2+平衡線,Fe2+的優(yōu)勢(shì)區(qū)域在整個(gè)E-pH圖中占的份額最重,而且Fe2+是可溶性的,會(huì)隨著汽水系統(tǒng)中的工質(zhì)遷徙,這會(huì)導(dǎo)致鍋爐汽水系統(tǒng)的進(jìn)一步腐蝕。并且產(chǎn)生的Fe2+會(huì)使得金屬管壁減薄,加重流動(dòng)加速腐蝕。所以,電廠中應(yīng)重點(diǎn)監(jiān)測(cè)Fe2+以及其水溶性衍生物Fe(OH)+。為了降低超臨界機(jī)組汽水腐蝕,可能存在給水系統(tǒng)最優(yōu)含氧量,因?yàn)槌R界水中溶解的氧促進(jìn)了保護(hù)性氧化膜的形成。
[Abstract]:With the increasing of environmental problems , the economic efficiency of coal - fired units is increased , and the discharge of pollutants in coal - fired units has become the main problem of coal - fired units . At present , high - parameter and large - capacity units are paid more attention by all walks of life because of their high economic efficiency . However , the continuous improvement of the steam parameters of the unit also increases the risk of corrosion of the steam - water system , so that the safety management of the heating surface of the thermal pipeline is facing a greater challenge .

In this paper , the migration of corrosion products of steam - water system is analyzed by theoretical analysis and calculation . The influence of different parameters on the migration of corrosion products is analyzed qualitatively . The migration process of corrosion products is also studied by combining the actual operation data of the power plant .

The generation of corrosion products in the steam - water system of the power plant is mainly the flow - accelerated corrosion of the low - temperature part and the high - temperature partial metal corrosion . The flow - accelerated corrosion is mainly the process of dissolution of the magnetic iron ore layer ( Fe304 ) on the surface of the carbon steel in ( single - phase ) flowing water or ( two - phase ) wet steam . The high - temperature corrosion of the metal is mainly the supercritical water or the oxidation reaction of the high - temperature steam and the metal matrix , and the double - layer oxide layer composed of Fe304 and FeCr2O4 is generated in general .

The main corrosion products in the steam - water system are Fe3O4 , Fe ( OH ) 2 , 偽 - Fe2O3 , Fe ( OH ) 4 - , 緯 - Fe2O3 , Fe ( OH ) 2 + , Fe ( OH ) 4 - , Fe3 + , Fe ( OH ) 3 , etc . According to the E - pH diagram , the most important corrosion product is Fe - Fe ~ ( 2 + ) .

【學(xué)位授予單位】：華北電力大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TM621

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本文編號(hào)：1842702