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  本文關(guān)鍵詞：燃煤煙氣細(xì)顆粒物湍流團(tuán)聚的研究　出處：《哈爾濱工業(yè)大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 細(xì)顆粒物 湍流團(tuán)聚 數(shù)值模擬 團(tuán)聚核函數(shù) 顆粒群平衡模型

【摘要】：細(xì)顆粒物（簡稱PM2.5）對環(huán)境和健康的影響已成為公眾和政府關(guān)注的焦點。燃煤電廠排煙是大氣中PM2.5的主要來源之一。由于PM2.5粒徑過小，傳統(tǒng)的除塵方式如采用電除塵器或布袋除塵器等均難以有效控制PM2.5的排放，所以在除塵器前設(shè)置預(yù)處理階段，即通過物理或化學(xué)的作用使PM2.5團(tuán)聚成粒徑較大的顆粒，然后再通過除塵器加以清除的方法成為除塵技術(shù)發(fā)展的新方向。在眾多新技術(shù)中，湍流團(tuán)聚因操作簡單，投資、運行成本低，具有較好的發(fā)展前景。 在物理作用導(dǎo)致的細(xì)顆粒物團(tuán)聚過程中，同時存在著幾種不同的團(tuán)聚機(jī)理，即布朗團(tuán)聚、湍流團(tuán)聚和電團(tuán)聚（或稱庫侖團(tuán)聚），其中電團(tuán)聚只有在顆粒帶電荷的情況下存在。根據(jù)這3種團(tuán)聚機(jī)理的作用范圍，并結(jié)合顆粒的初始粒徑分布，本文首先確定了團(tuán)聚核函數(shù)，然后研究了顆粒尺度和煙氣溫度對團(tuán)聚核函數(shù)的影響，結(jié)果表明：隨著煙氣溫度的升高，團(tuán)聚核增大，但變化幅度不大；在單分散系統(tǒng)中，布朗團(tuán)聚效果最差，在多分散系統(tǒng)中，布朗團(tuán)聚核隨著顆粒粒徑差值的增大而增大；而電團(tuán)聚則是隨著顆粒粒徑的增大而增大，與粒徑差值無關(guān)。 在確定了團(tuán)聚核函數(shù)后，本文結(jié)合氣固兩相流動和顆粒團(tuán)聚過程分析了兩種擾流裝置（即擾流圓柱和渦片）的結(jié)構(gòu)及其參數(shù)對團(tuán)聚效果和系統(tǒng)壓降的影響。結(jié)果表明：對于擾流圓柱而言，垂直于流動方向并列布置時具有較好的團(tuán)聚效果，且隨著圓柱間距的增大，顆粒團(tuán)聚效果逐漸增強(qiáng)，但增量很��；對于渦片而言，“+”字形結(jié)構(gòu)比“ ”字形結(jié)構(gòu)具有更好的團(tuán)聚效果，大體上，隨行（列）間距的增大團(tuán)聚效果逐漸減弱；但系統(tǒng)壓降隨行間距的增大而減少，隨列間距的增大而增加。綜合顆粒團(tuán)聚和壓力損失這兩方面的因素，渦片的行間距為250mm、列間距為100mm時，效果較好。 基于擾流圓柱和渦片的擾流特點，本文將兩者相結(jié)合，構(gòu)造了一種新型湍流凝聚器。通過數(shù)值模擬，研究了新型湍流凝聚器的團(tuán)聚效果，并探討了煙氣流速對團(tuán)聚結(jié)果的影響。結(jié)果表明：新型湍流凝聚器中產(chǎn)生的大尺度湍流明顯有利于較小顆粒（小于1μm）的團(tuán)聚，產(chǎn)生的小尺度湍流明顯有利于較大顆粒（大于1μm）的團(tuán)聚；煙氣流速越大，，團(tuán)聚效果越差，同時系統(tǒng)壓降也越高。
[Abstract]:Fine particulate matter (PM2.5). The impact on environment and health has become the focus of public and government attention. Coal fired power plant exhaust smoke is one of the main sources of PM2.5 in the atmosphere. Because of PM2.5 particle size is too small. Traditional dust collection methods such as electric precipitator or bag dust collector are difficult to effectively control the emission of PM2.5, so the pre-treatment stage is set before the dust collector. That is to say, the method of agglomeration of PM2.5 into larger particles by physical or chemical action and then cleaning by dust remover becomes a new direction in the development of dust removal technology. Turbulence agglomeration has a good prospect because of its simple operation, investment and low operating cost. In the process of fine particle agglomeration caused by physical action, there are several different agglomeration mechanisms, i.e. Brownian agglomeration, turbulent agglomeration and electric agglomeration (or Coulomb agglomeration). Electric agglomeration exists only in the case of charged particles. According to the range of the three agglomeration mechanisms and the initial particle size distribution, the agglomeration kernel function is first determined. The effect of particle size and flue gas temperature on the agglomeration kernel function is studied. The results show that the agglomeration nucleus increases with the increase of flue gas temperature, but the change is not significant. In the monodisperse system, the effect of Brownian agglomeration is the worst. In the polydisperse system, the Brownian agglomeration nucleus increases with the increase of particle size difference. The electric agglomeration increases with the increase of particle size, which is independent of the particle size difference. After determining the aggregation kernel function. Combined with gas-solid two-phase flow and particle agglomeration process, two kinds of scrambling devices (i.e. scrambling cylinder and vortex plate) are analyzed in this paper. The effect of the structure and its parameters on the agglomeration effect and the pressure drop of the system is obtained. The agglomeration effect is better when parallel arrangement is perpendicular to the flow direction, and the agglomeration effect increases gradually with the increase of cylinder spacing, but the increment is very small. For the vortex sheet, the "zigzag" structure has a better agglomeration effect than the "zigzag" structure. On the whole, the agglomeration effect of the increase of the accompanying (column) spacing gradually weakens. However, the pressure drop of the system decreases with the increase of the spacing, and increases with the increase of the spacing of the columns. When the row spacing is 250mm and the column spacing is 100mm, considering the two factors of particle agglomeration and pressure loss. The effect is good. Based on the scrambling characteristics of a turbulent cylinder and a vortex, a new type of turbulent condenser is constructed by combining them. The agglomeration effect of the new turbulence condenser is studied by numerical simulation. The effect of flue gas velocity on agglomeration results is discussed. The results show that the large scale turbulence produced in the new turbulent condenser is obviously beneficial to the agglomeration of smaller particles (less than 1 渭 m). The small scale turbulence is obviously favorable for the agglomeration of larger particles (> 1 渭 m). The higher the flue gas velocity, the worse the agglomeration effect and the higher the pressure drop of the system.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：X773

【引證文獻(xiàn)】

相關(guān)期刊論文 前1條

1 鄭建祥;許帥;王京陽;;超細(xì)顆粒聚團(tuán)模型及湍流聚并器聚團(tuán)研究[J];中國電機(jī)工程學(xué)報;2016年16期

相關(guān)碩士學(xué)位論文 前1條

1 姚躍輝;脫汞用活性焦顆粒在袋式除塵器內(nèi)沉積特性研究[D];東華大學(xué);2016年

本文編號：1382953