【摘要】：超(超)臨界火電機(jī)組可以顯著地提高電站機(jī)組效率、降低CO2排放量,是我國火電發(fā)展的主要方向。但是隨著蒸汽參數(shù)的提高,電站鍋爐高溫受熱面尤其是過熱器管材料將處于具有極強(qiáng)腐蝕性的超臨界水環(huán)境中。發(fā)電廠高溫鍋爐管蒸汽側(cè)氧化皮脫落堵塞引起的超溫、爆管,影響超超臨界鍋爐長(zhǎng)期安全、穩(wěn)定運(yùn)行。因此,探究不同蒸汽參數(shù)對(duì)鍋爐管腐蝕特性的研究,有助于揭示氧化膜的生長(zhǎng)與剝落機(jī)理。因此,開展不同參數(shù)下的氧化膜腐蝕機(jī)理研究具有重要意義。本論文主要開展了馬氏體鋼P(yáng)92以及奧氏體鋼TP347HFG在不同溫度、壓力、溶解氧以及不同流動(dòng)狀態(tài)下的氧化試驗(yàn)。溫度為550-700℃、壓力為0.1-25MPa、溶解氧為0-2000ppb、流速為0-5ml/min。獲得了兩種鋼在不同溫度、壓力、流速以及溶解氧下的氧化動(dòng)力學(xué)曲線,并且利用掃描電鏡和X射線衍射儀分析了氧化膜的微觀形貌以及主要的氧化物相成分。此外,利用同位素標(biāo)記法(18O2+H216O)探究了P92鋼在2000ppb溶解氧超臨界水中的氧化特性,獲得溶解氧在超臨界水中的作用機(jī)理。通過分析馬氏體鋼P(yáng)92與奧氏體鋼TP347HFG在不同溫度下的氧化特性,發(fā)現(xiàn)鐵離子沿著氧化膜內(nèi)層的擴(kuò)散是馬氏體鋼氧化速率的控制因素,并且溫度的變化會(huì)影響兩種鋼的氧化動(dòng)力學(xué)。通過分析壓力的影響,發(fā)現(xiàn)隨著壓力的增大馬氏體鋼P(yáng)92的氧化速率逐漸增大,尤其是處于超臨界狀態(tài)時(shí)氧化速率急劇增加。通過不同溶解氧環(huán)境實(shí)驗(yàn)以及同位素標(biāo)記實(shí)驗(yàn),發(fā)現(xiàn)溶解氧不但參與了氧化反應(yīng)并且提高了超臨界水環(huán)境的氧化還原電位,提高了氧化膜的生長(zhǎng)速率。并且溶解氧量的大小會(huì)顯著影響氧化膜物相成分。結(jié)合實(shí)驗(yàn)結(jié)果,分析了馬氏體鋼P(yáng)92與奧氏體鋼TP347HFG氧化膜的剝落特性,獲得了兩種鋼在超臨界水氧化過程中的剝落機(jī)理。
[Abstract]:Supercritical thermal power units can significantly improve the efficiency of power plant units and reduce CO2 emissions, which is the main direction of thermal power development in China. However, with the increase of steam parameters, the high temperature heating surface of power plant boiler, especially the superheater tube material, will be in the extremely corrosive supercritical water environment. The long term safe and stable operation of the ultra-supercritical boiler is affected by the excessive temperature and tube burst caused by the exfoliation and blockage of the steam side of the high temperature boiler tube in power plant. Therefore, studying the corrosion characteristics of boiler tubes with different steam parameters is helpful to reveal the growth and spalling mechanism of oxide film. Therefore, it is of great significance to study the corrosion mechanism of oxide film under different parameters. In this paper, the oxidation tests of martensite steel P92 and austenitic steel TP347HFG at different temperature, pressure, dissolved oxygen and flow state were carried out. The temperature is 550-700 鈩，

本文編號(hào)：2123560