【摘要】：我國(guó)能源結(jié)構(gòu)中煤炭的主體地位在較長(zhǎng)的時(shí)間內(nèi)不會(huì)改變,提高能源即煤炭的燃燒利用效率及減少污染是當(dāng)下關(guān)注的焦點(diǎn)問(wèn)題之一。超臨界鍋爐具備了解決這兩方面問(wèn)題的能力,在燃煤電廠中廣泛采用。本文針對(duì)某超臨界對(duì)沖鍋爐,利用FLUENT軟件對(duì)該鍋爐不同工況進(jìn)行數(shù)值模擬,確定最佳參數(shù),從而實(shí)現(xiàn)燃燒優(yōu)化的目的。 本文選用的模型載體為某電廠型號(hào)為DG2090/25.4-117的超臨界直流鍋爐,依托數(shù)值模擬軟件,進(jìn)行爐內(nèi)各過(guò)程模擬研究。對(duì)于氣固兩相間氣相湍流計(jì)算采用RNG k-ε模型；對(duì)于煤顆粒揮發(fā)分的釋放采用了雙方程競(jìng)爭(zhēng)反應(yīng)模型；對(duì)于氣相湍流燃燒采用混合分?jǐn)?shù)-概率密度函數(shù)模型；對(duì)于焦炭燃燒采用運(yùn)動(dòng)／擴(kuò)散控制燃燒模型；對(duì)于鍋爐內(nèi)輻射換熱采用P-1輻射模型；對(duì)于煤顆粒的軌跡采用隨機(jī)顆粒軌道模型；最后介紹了離散相與連續(xù)相之間的耦合計(jì)算模型。 首先,對(duì)該鍋爐100%BMCR工況進(jìn)行模擬,對(duì)爐內(nèi)速度場(chǎng)、溫度場(chǎng)、氧氣濃度分布及NO濃度分布進(jìn)行了詳盡的討論,總結(jié)了前后墻對(duì)沖鍋爐燃燒特點(diǎn),理論上證明模擬結(jié)果的準(zhǔn)確性,計(jì)算結(jié)果爐膛出口溫度與NO排放濃度與鍋爐實(shí)際運(yùn)行數(shù)據(jù)對(duì)比基本符合,證明模擬結(jié)果可以較完整的反映實(shí)際運(yùn)行,從而可以對(duì)變工況進(jìn)行深入研究。其次,本文通過(guò)改變旋流二次風(fēng)的旋流強(qiáng)度、過(guò)量空氣系數(shù)及燃盡風(fēng)風(fēng)率,分析這些參數(shù)對(duì)鍋爐安全運(yùn)行、燃燒效率及NO排放量的影響,從而得到合理參數(shù),為鍋爐安全經(jīng)濟(jì)運(yùn)行提供參考。
[Abstract]:The dominant position of coal in China's energy structure will not change for a long time. One of the focus problems is to improve the efficiency of coal combustion and reduce pollution. Supercritical boilers have the ability to solve these two problems and are widely used in coal-fired power plants. In this paper, for a supercritical hedging boiler, the numerical simulation of the boiler under different working conditions is carried out by using FLUENT software, and the optimum parameters are determined to realize the purpose of combustion optimization. The model carrier selected in this paper is a supercritical once-through boiler with DG2090/25.4-117 model in a power plant. The numerical simulation software is used to simulate each process in the boiler. RNG k- 蔚 model is used for gas-solid two-phase turbulence calculation, two-equation competitive reaction model is used for the release of volatile matter from coal particles, and mixed fracture-probability density function model is used for gas-phase turbulent combustion. Motion / diffusion controlled combustion model is used for coke combustion, P-1 radiation model is used for radiative heat transfer in boiler, random particle orbit model is used for coal particle trajectory. Finally, the coupling calculation model between discrete phase and continuous phase is introduced. Firstly, the 100%BMCR operating conditions of the boiler are simulated, and the velocity field, temperature field, oxygen concentration distribution and NO concentration distribution in the boiler are discussed in detail, and the combustion characteristics of the front and rear wall hedge boiler are summarized. The accuracy of the simulation results is proved theoretically, and the comparison between the furnace outlet temperature and the NO emission concentration and the actual operation data of the boiler is basically consistent. It is proved that the simulation results can reflect the actual operation more completely. Thus, it is possible to carry on the thorough research to the variable working condition. Secondly, by changing the swirl intensity, excess air coefficient and burnout air rate of swirl secondary air, the effects of these parameters on boiler safe operation, combustion efficiency and NO emission are analyzed, and the reasonable parameters are obtained. It provides reference for safe and economical operation of boiler.
【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
【分類號(hào)】：TM621.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前6條

1 王麗英;大型鍋爐墻置對(duì)沖燃燒技術(shù)[J];華東電力;2002年09期

2 熊蔚立;黃偉;彭敏;;超臨界鍋爐技術(shù)特點(diǎn)及發(fā)展方向[J];湖南電力;2008年04期

3 方慶艷;汪華劍;陳剛;周懷春;;燃盡風(fēng)對(duì)超超臨界鍋爐燃燒特性影響的數(shù)值模擬[J];華中科技大學(xué)學(xué)報(bào)(自然科學(xué)版);2010年11期

4 朱彤,范衛(wèi)東,信偉,陳力哲,吳少華,秦裕琨;雙爐膛爐內(nèi)空氣動(dòng)力場(chǎng)的數(shù)值模擬研究[J];熱能動(dòng)力工程;1997年06期

5 岑可法,樊建人;數(shù)值試驗(yàn)(CAT)在大型電站鍋爐設(shè)計(jì)及調(diào)試中應(yīng)用的前景——(Ⅰ)基礎(chǔ)理論[J];浙江大學(xué)學(xué)報(bào)(自然科學(xué)版);1992年01期

6 岑可法,樊建人;數(shù)值試驗(yàn)(CAT)在大型電站鍋爐設(shè)計(jì)及調(diào)試中應(yīng)用的前景——(Ⅱ)應(yīng)用實(shí)例[J];浙江大學(xué)學(xué)報(bào)(自然科學(xué)版);1992年02期

，

本文編號(hào)：2402751