生物質(zhì)混燃鍋爐受熱面金屬的腐蝕特性研究
發(fā)布時(shí)間：2018-12-12 00:18
【摘要】：化石能源的日益枯竭和環(huán)境的嚴(yán)重污染已成為人類面臨的兩大問題,因此能源的可再生性和對(duì)環(huán)境友好性是人們關(guān)注的焦點(diǎn)。生物質(zhì)能作為一種可再生的清潔能源,具有分布廣泛及數(shù)量巨大等特點(diǎn),其在利用過程中能夠?qū)崿F(xiàn)碳的零排放,并且硫氮的排放量也較化石燃料燃燒少很多�，F(xiàn)階段,生物質(zhì)燃燒發(fā)電是生物質(zhì)能大規(guī)模利用的方式之一,而其與煤混合燃燒更能消除純生物質(zhì)電廠初期投資高、原料供應(yīng)不穩(wěn)定、規(guī)模容量受限以及經(jīng)濟(jì)效益不高等問題。但是生物質(zhì)中鈉、鉀等堿金屬元素及氯元素含量較高,煤中含有硫元素,在混燃過程中生成HCl、堿金屬氯化物和堿金屬硫酸鹽等物質(zhì),在一定溫度等條件下,這些物質(zhì)非常容易導(dǎo)致鍋爐受熱面金屬結(jié)渣、積灰和腐蝕等問題。本文研究不同組分合成灰對(duì)鍋爐受熱面金屬的腐蝕特性,探究了不同工況下受熱面金屬腐蝕的特性規(guī)律。對(duì)合成灰腐蝕反應(yīng)采用熱分析動(dòng)力學(xué)研究,定量表征合成灰腐蝕反應(yīng)過程。探討了幾種常見添加劑對(duì)生物質(zhì)混煤燃燒受熱面金屬腐蝕的影響規(guī)律。利用管式爐模擬生物質(zhì)混煤燃燒鍋爐過熱器區(qū)域的反應(yīng)條件,配制合成灰涂抹在金屬20G表面,采用增重法,進(jìn)行受熱面金屬氯腐蝕特性試驗(yàn)。結(jié)果表明生物質(zhì)混燃鍋爐受熱面金屬的腐蝕特性均符合拋物線規(guī)律,受熱面金屬的積灰對(duì)腐蝕的影響相當(dāng)大,腐蝕速率比無灰增加40%多,同時(shí)積灰腐蝕生成的腐蝕產(chǎn)物中C1含量較高。不同組分合成灰對(duì)受熱面金屬的腐蝕程度不同。混合有氯化鈉和氯化鉀后合成灰的腐蝕性大大增加,但腐蝕性強(qiáng)弱與氯化鈉和氯化鉀混合的比例關(guān)系不大。堿金屬硫酸鹽的混合會(huì)降低腐蝕速率,遠(yuǎn)低于硫酸鈉或者硫酸鉀單獨(dú)出現(xiàn)時(shí)的腐蝕速率。氯化鈉和硫酸鈉所產(chǎn)生的協(xié)同作用,會(huì)使合成灰對(duì)金屬的腐蝕速率達(dá)到最大。當(dāng)合成灰中氯化鉀和硫酸鉀的比例為1：1時(shí),腐蝕速率最低,但隨著鉀鹽比例的變化,腐蝕速率的變化未見明顯的規(guī)律。隨著HCl體積分?jǐn)?shù)的增加,HCl更容易穿過氧化膜向金屬基體滲透,與金屬發(fā)生反應(yīng)生成金屬氯化物,腐蝕速率幾乎成線性增加。隨著反應(yīng)溫度由450℃升高到650℃時(shí),腐蝕速率隨著溫度的升高成指數(shù)增加,符合阿倫尼烏斯定律。尤其溫度從550℃升高到600℃,腐蝕速率急劇增大,溫度對(duì)該溫度區(qū)間腐蝕的影響幅度明顯變大。采取定溫法,對(duì)涂有合成灰的受熱面金屬腐蝕進(jìn)行熱分析動(dòng)力學(xué)研究,表明腐蝕符合二維擴(kuò)散模式,得到D2模式函數(shù)下的動(dòng)力學(xué)方程：量的表征受熱面金屬腐蝕的反應(yīng)過程。含有添加劑的合成灰對(duì)受熱面金屬的腐蝕過程也符合拋物線規(guī)律,含有添加劑的合成灰D17的腐蝕性大小順序?yàn)椋禾砑覣l2O3D17添加SiO2添加CaO添加高嶺土。試樣表面腐蝕產(chǎn)物中Fe含量越高,金屬基體被腐蝕的程度越大,Fe從金屬中被置換到表面的腐蝕產(chǎn)物中。含有添加劑的堿金屬氯化物的腐蝕性大小順序?yàn)椋禾砑覵iO2D6添加CaO添加Al2O3添加高嶺土,高嶺土中含有的Al和Si元素會(huì)捕獲堿金屬氯化物,形成硅酸鋁鉀。硅酸鋁和堿金屬反應(yīng)會(huì)生成更高熔點(diǎn)的堿金屬硅鋁酸鹽,在燃燒中提升了積灰的熔點(diǎn),可以有效地減緩腐蝕。綜合看來,不同種類添加劑加入不同組分合成灰后,原合成灰的腐蝕性大小變化有所不同。添加劑Al2O3和高嶺土相比于其他幾種添加劑,對(duì)于降低腐蝕速率和減緩腐蝕有較好的效果。對(duì)于堿金屬氯化物腐蝕,合成灰加入高嶺土后,腐蝕速率降低16.1%。對(duì)于堿金屬硫酸鹽腐蝕、鈉鹽腐蝕和鉀鹽腐蝕,合成灰加入添加劑Al2O3后,腐蝕速率分別降低45.3%、13.1%和34.3%。
[Abstract]:The increasing depletion of the fossil energy and the serious pollution of the environment have become the two major problems facing mankind, so the renewable and environmental-friendly energy of the energy is the focus of the people's attention. As a kind of renewable clean energy, the biomass energy has the characteristics of wide distribution and large quantity, and can realize zero discharge of carbon in the utilization process, and the amount of sulfur and nitrogen is much less than that of the fossil fuel. At present, biomass combustion power generation is one of the ways of mass utilization of biomass energy, which can eliminate the problems of high initial investment of pure biomass power plant, unstable supply of raw materials, limited capacity of scale and high economic benefit. but the content of alkali metal elements and chlorine elements such as sodium and potassium in the biomass is high, sulfur elements are contained in the coal, and substances such as HCl, alkali metal chloride and alkali metal sulfate are generated in the mixed combustion process, and under the conditions of certain temperature and the like, the substances are very easy to cause the metal junction slag of the heating surface of the boiler, and the problems of ash deposit and corrosion and the like are solved. The corrosion characteristics of the metal in the heating surface of the boiler are studied in this paper, and the characteristics of the metal corrosion of the heating surface under different working conditions are investigated. The process of the synthetic ash corrosion reaction was quantitatively characterized by the thermal analysis kinetic study of the synthetic ash corrosion reaction. The effect of several common additives on the metal corrosion of the heated surface of the biomass mixed coal is discussed. The reaction conditions of the superheater area of the biomass mixed coal combustion boiler are simulated by a tubular furnace, and the synthetic ash is applied to the surface of the metal 20G, and the weight gain method is adopted to test the metal chloride corrosion characteristic of the heated surface. The results show that the corrosion characteristics of the metal in the heated surface of the biomass-mixed-burn boiler are in accordance with the law of the parabola, the effect of the deposition of the metal on the surface of the heated surface on the corrosion is quite large, the corrosion rate is more than 40% higher than that of the ash-free, and the content of C1 in the corrosion products generated by the corrosion of the ash is high. The degree of corrosion of different component synthetic ash to the metal of the heated surface is different. The corrosion of the synthetic ash after mixing with sodium chloride and potassium chloride is greatly increased, but the ratio of the corrosivity to the mixture of sodium chloride and potassium chloride is not small. The mixing of the alkali metal sulfates can reduce the corrosion rate, much lower than the corrosion rate at the time of the individual presence of sodium sulfate or potassium sulfate. The synergistic effect of sodium chloride and sodium sulfate can maximize the corrosion rate of the synthetic ash to the metal. When the ratio of potassium chloride and potassium sulfate in the synthetic ash is 1: 1, the corrosion rate is the lowest, but with the change of the proportion of the potassium salt, the change of the corrosion rate is not obvious. With the increase of the volume fraction of HCl, HCl is more easily permeable to the metal matrix through the oxide film, and the metal chloride is generated by reaction with the metal, and the corrosion rate is almost linearly increased. As the reaction temperature increased from 450.degree. C. to 650.degree. C., the corrosion rate increased exponentially with the increase in temperature, in accordance with the Arrhenius law. in particular, that temperature increase from 550 DEG C to 600 DEG C, the corrosion rate is rapidly increase, and the influence of the temperature on the corrosion of the temperature range is obviously changed. The thermal analysis of the metal corrosion of the heated surface coated with the synthetic ash was studied by the method of constant temperature. The results show that the corrosion is in the two-dimensional diffusion mode, and the kinetic equation under the function of the D2 mode is obtained. The reaction process of the metal corrosion of the heated surface is characterized by the quantity. The corrosion process of the composite ash containing the additive to the metal of the heated surface is also in accordance with the parabolic law. The order of the corrosivity of the synthetic ash D17 containing the additive is as follows: adding the SiO2 to the Al2O3D17 to add the CaO and adding the kaolin. The higher the Fe content in the sample surface corrosion product, the greater the degree of corrosion of the metal matrix, and the removal of Fe from the metal to the corrosion product of the surface. The order of the corrosivity of the alkali metal chloride containing the additive is that the addition of SiO2 to the addition of CaO to the Al2O3 is added, and the Al and Si elements contained in the kaolin can capture the alkali metal chloride to form the potassium aluminum silicate. The reaction of the aluminum silicate and the alkali metal will produce a higher melting point alkali metal aluminosilicate, which increases the melting point of the ash deposit in the combustion and can effectively slow down the corrosion. It can be seen that different kinds of additives can be used to synthesize ash with different components, and the change of the corrosivity of the original synthetic ash is different. Compared with other additives, the additive Al2O3 and the kaolin have a better effect on the reduction of the corrosion rate and the reduction of corrosion. For alkali metal chloride corrosion, the corrosion rate is reduced by 16.1% after the synthetic ash is added to the kaolin. The corrosion rate of alkali metal sulfate, the corrosion of the sodium salt and the corrosion of the potassium salt, and the addition of the additive Al2O3, the corrosion rate was decreased by 45.3%, 13.1% and 33.4%, respectively.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TM619
本文編號(hào)：2373513
[Abstract]:The increasing depletion of the fossil energy and the serious pollution of the environment have become the two major problems facing mankind, so the renewable and environmental-friendly energy of the energy is the focus of the people's attention. As a kind of renewable clean energy, the biomass energy has the characteristics of wide distribution and large quantity, and can realize zero discharge of carbon in the utilization process, and the amount of sulfur and nitrogen is much less than that of the fossil fuel. At present, biomass combustion power generation is one of the ways of mass utilization of biomass energy, which can eliminate the problems of high initial investment of pure biomass power plant, unstable supply of raw materials, limited capacity of scale and high economic benefit. but the content of alkali metal elements and chlorine elements such as sodium and potassium in the biomass is high, sulfur elements are contained in the coal, and substances such as HCl, alkali metal chloride and alkali metal sulfate are generated in the mixed combustion process, and under the conditions of certain temperature and the like, the substances are very easy to cause the metal junction slag of the heating surface of the boiler, and the problems of ash deposit and corrosion and the like are solved. The corrosion characteristics of the metal in the heating surface of the boiler are studied in this paper, and the characteristics of the metal corrosion of the heating surface under different working conditions are investigated. The process of the synthetic ash corrosion reaction was quantitatively characterized by the thermal analysis kinetic study of the synthetic ash corrosion reaction. The effect of several common additives on the metal corrosion of the heated surface of the biomass mixed coal is discussed. The reaction conditions of the superheater area of the biomass mixed coal combustion boiler are simulated by a tubular furnace, and the synthetic ash is applied to the surface of the metal 20G, and the weight gain method is adopted to test the metal chloride corrosion characteristic of the heated surface. The results show that the corrosion characteristics of the metal in the heated surface of the biomass-mixed-burn boiler are in accordance with the law of the parabola, the effect of the deposition of the metal on the surface of the heated surface on the corrosion is quite large, the corrosion rate is more than 40% higher than that of the ash-free, and the content of C1 in the corrosion products generated by the corrosion of the ash is high. The degree of corrosion of different component synthetic ash to the metal of the heated surface is different. The corrosion of the synthetic ash after mixing with sodium chloride and potassium chloride is greatly increased, but the ratio of the corrosivity to the mixture of sodium chloride and potassium chloride is not small. The mixing of the alkali metal sulfates can reduce the corrosion rate, much lower than the corrosion rate at the time of the individual presence of sodium sulfate or potassium sulfate. The synergistic effect of sodium chloride and sodium sulfate can maximize the corrosion rate of the synthetic ash to the metal. When the ratio of potassium chloride and potassium sulfate in the synthetic ash is 1: 1, the corrosion rate is the lowest, but with the change of the proportion of the potassium salt, the change of the corrosion rate is not obvious. With the increase of the volume fraction of HCl, HCl is more easily permeable to the metal matrix through the oxide film, and the metal chloride is generated by reaction with the metal, and the corrosion rate is almost linearly increased. As the reaction temperature increased from 450.degree. C. to 650.degree. C., the corrosion rate increased exponentially with the increase in temperature, in accordance with the Arrhenius law. in particular, that temperature increase from 550 DEG C to 600 DEG C, the corrosion rate is rapidly increase, and the influence of the temperature on the corrosion of the temperature range is obviously changed. The thermal analysis of the metal corrosion of the heated surface coated with the synthetic ash was studied by the method of constant temperature. The results show that the corrosion is in the two-dimensional diffusion mode, and the kinetic equation under the function of the D2 mode is obtained. The reaction process of the metal corrosion of the heated surface is characterized by the quantity. The corrosion process of the composite ash containing the additive to the metal of the heated surface is also in accordance with the parabolic law. The order of the corrosivity of the synthetic ash D17 containing the additive is as follows: adding the SiO2 to the Al2O3D17 to add the CaO and adding the kaolin. The higher the Fe content in the sample surface corrosion product, the greater the degree of corrosion of the metal matrix, and the removal of Fe from the metal to the corrosion product of the surface. The order of the corrosivity of the alkali metal chloride containing the additive is that the addition of SiO2 to the addition of CaO to the Al2O3 is added, and the Al and Si elements contained in the kaolin can capture the alkali metal chloride to form the potassium aluminum silicate. The reaction of the aluminum silicate and the alkali metal will produce a higher melting point alkali metal aluminosilicate, which increases the melting point of the ash deposit in the combustion and can effectively slow down the corrosion. It can be seen that different kinds of additives can be used to synthesize ash with different components, and the change of the corrosivity of the original synthetic ash is different. Compared with other additives, the additive Al2O3 and the kaolin have a better effect on the reduction of the corrosion rate and the reduction of corrosion. For alkali metal chloride corrosion, the corrosion rate is reduced by 16.1% after the synthetic ash is added to the kaolin. The corrosion rate of alkali metal sulfate, the corrosion of the sodium salt and the corrosion of the potassium salt, and the addition of the additive Al2O3, the corrosion rate was decreased by 45.3%, 13.1% and 33.4%, respectively.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TM619
【引證文獻(xiàn)】
相關(guān)會(huì)議論文 前1條
1 張軍;盛昌棟;魏?jiǎn)|;;生物質(zhì)燃燒過程中受熱面的腐蝕性機(jī)理和防范措施[A];長(zhǎng)三角清潔能源論壇論文專輯[C];2005年
，本文編號(hào)：2373513
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