旋轉(zhuǎn)填充床流體流動(dòng)可視化與傳質(zhì)模型研究
發(fā)布時(shí)間：2018-08-30 09:43
【摘要】：化學(xué)工業(yè)是我國國民經(jīng)濟(jì)的支柱產(chǎn)業(yè),為我國社會(huì)經(jīng)濟(jì)發(fā)展和國防建設(shè)提供了大量的化學(xué)品和基礎(chǔ)材料,同時(shí)也產(chǎn)生廢水、廢氣等有害污染物質(zhì),嚴(yán)重制約著我國化學(xué)工業(yè)的可持續(xù)發(fā)展。化工生產(chǎn)過程清潔、節(jié)能降耗一直是科學(xué)家和工程師們的目標(biāo),作為化工過程強(qiáng)化裝備的旋轉(zhuǎn)填充床的研究與工業(yè)應(yīng)用有助于實(shí)現(xiàn)這一目標(biāo)。旋轉(zhuǎn)填充床的多孔填料可以將液體切割成細(xì)小的液滴和液膜,氣液接觸面積急劇增大,具有優(yōu)異的質(zhì)量傳遞和微觀分子混合性能。端效應(yīng)區(qū)是旋轉(zhuǎn)填充床填料內(nèi)緣處傳質(zhì)和混合最劇烈的區(qū)域,根據(jù)端效應(yīng)區(qū)的特征,旋轉(zhuǎn)填充床的傳質(zhì)被劃分為端效應(yīng)區(qū)、填料主體區(qū)和空腔區(qū),簡稱“三區(qū)”。然而,由于旋轉(zhuǎn)填充床中流體運(yùn)動(dòng)速度較快不易觀測(cè),導(dǎo)致其各區(qū)域內(nèi)流體流動(dòng)形態(tài)及尺寸的研究還不系統(tǒng)。對(duì)旋轉(zhuǎn)填充床傳質(zhì)有重要影響的空腔區(qū)及端效應(yīng)區(qū)的傳質(zhì)研究還有待加強(qiáng),這些流體流動(dòng)和傳質(zhì)等基礎(chǔ)研究的滯后均阻礙了旋轉(zhuǎn)填充床的進(jìn)一步結(jié)構(gòu)優(yōu)化和工業(yè)應(yīng)用。本文首先采用高速攝像技術(shù)對(duì)空腔區(qū)流體流動(dòng)進(jìn)行觀測(cè),并對(duì)空腔區(qū)傳質(zhì)表面積進(jìn)行模型化研究。通過概率計(jì)算劃分了端效應(yīng)區(qū)和填料主體區(qū),建立了包含旋轉(zhuǎn)填充床的端效應(yīng)區(qū)、填料主體區(qū)和空腔區(qū)為傳質(zhì)過程的液相體積傳質(zhì)系數(shù)模型,即三區(qū)液相傳質(zhì)模型。并結(jié)合氣相傳質(zhì)和化學(xué)反應(yīng)的影響,將三區(qū)傳質(zhì)模型用于單乙醇胺(MEA)吸收CO_2過程的預(yù)測(cè),可為旋轉(zhuǎn)填充床的設(shè)計(jì)和應(yīng)用提供理論指導(dǎo)。主要研究結(jié)果如下:1.利用高速攝像技術(shù)對(duì)旋轉(zhuǎn)填充床空腔區(qū)內(nèi)的流體流動(dòng)狀態(tài)進(jìn)行研究,系統(tǒng)考察了轉(zhuǎn)速、液體體積流量、填料外半徑、液體粘度和表面張力對(duì)空腔區(qū)流體流型、液滴平均直徑、液滴大小、尺寸分布及液滴平均速度的影響規(guī)律。結(jié)果表明:空腔區(qū)存在兩種典型的流型(液滴流和液線流)以及兩種液體斷裂方式(液線-液滴和液膜-液線-液滴),同時(shí)獲得不同操作條件下的液體流型轉(zhuǎn)變判據(jù);液滴平均直徑隨著轉(zhuǎn)速、填料外半徑和液體粘度的增加而減小,隨著液體表面張力的增大而略微增大,液體初始速度對(duì)液滴平均直徑的影響不大;液滴大小分布符合R-R分布,分布指數(shù)m范圍為4.47到9.43之間。液滴平均合速度和徑向速度主要隨轉(zhuǎn)速和填料外半徑的增大而增大,受液體初始速度、液體粘度和表面張力的影響不大。通過量綱分析得到了液滴平均直徑和速度的關(guān)聯(lián)式,預(yù)測(cè)值與實(shí)驗(yàn)值誤差分別在±20%和±10%以內(nèi)。2.基于空腔區(qū)流體流動(dòng)的可視化研究,發(fā)現(xiàn)空腔區(qū)的傳質(zhì)貢獻(xiàn)分為三部分,分別為母代液滴、器壁液膜和子代液滴,對(duì)上述三部分進(jìn)行模型化,建立空腔區(qū)總傳質(zhì)表面積模型。從模型結(jié)果可以看出,相比母代液滴的傳質(zhì),器壁液膜和子代液滴的傳質(zhì)表面積對(duì)空腔區(qū)總傳質(zhì)表面積貢獻(xiàn)最大。采用NaOH-CO_2實(shí)驗(yàn)體系考察了轉(zhuǎn)速、液體初始速度和填料外半徑對(duì)空腔區(qū)傳質(zhì)表面積的影響,并與模型預(yù)測(cè)值進(jìn)行對(duì)比。結(jié)果表明,空腔區(qū)傳質(zhì)表面積預(yù)測(cè)值和實(shí)驗(yàn)值誤差在±20%以內(nèi),說明模型可較好的描述空腔區(qū)的傳質(zhì)表面積。3.利用概率計(jì)算的方法得到端效應(yīng)區(qū)厚度,結(jié)合端效應(yīng)區(qū)厚度、以及前人對(duì)旋轉(zhuǎn)填充床填料區(qū)流體流動(dòng)狀態(tài)和傳質(zhì)理論研究的結(jié)果,建立了包含端效應(yīng)區(qū)、填料主體區(qū)和空腔區(qū)的液相體積傳質(zhì)系數(shù)模型,即三區(qū)液相傳質(zhì)模型,并通過NaOH-CO_2化學(xué)吸收實(shí)驗(yàn)驗(yàn)證模型值與實(shí)驗(yàn)值誤差在±15%以內(nèi),說明模型可以很好的預(yù)測(cè)旋轉(zhuǎn)填充床的液相傳質(zhì)過程,為旋轉(zhuǎn)填充床的設(shè)計(jì)提供理論支撐。4.基于三區(qū)液相傳質(zhì)模型,同時(shí)考慮氣相傳質(zhì)和化學(xué)反應(yīng)對(duì)傳質(zhì)的影響,將三區(qū)模型用于MEA-CO_2吸收過程的預(yù)測(cè),結(jié)果表明,大部分實(shí)驗(yàn)值與模型預(yù)測(cè)值吻合良好,誤差在±20%以內(nèi),CO_2吸收率隨著轉(zhuǎn)子轉(zhuǎn)速的增加先增大后略微減小,隨著液體體積流量和MEA濃度的增加而增大,隨著氣體體積流量的增加而減小。
[Abstract]:Chemical industry is the pillar industry of China's national economy. It provides a large number of chemicals and basic materials for China's social and economic development and national defense construction. At the same time, it produces harmful pollutants such as waste water and exhaust gas, which seriously restricts the sustainable development of China's chemical industry. The goal of the engineers is that the research and industrial application of rotating packed beds as chemical process intensification equipment will help to achieve this goal. According to the characteristics of the end-effect zone, the mass transfer in the rotating packed bed is divided into the end-effect zone, the main filler zone and the cavity zone, which are called "three zones". However, the velocity of fluid movement in the rotating packed bed is not easy to be observed, resulting in the flow pattern and flow pattern in each zone. The study of mass transfer in cavity region and end effect region, which have important influence on mass transfer in rotating packed bed, needs to be strengthened. The lag of basic research on fluid flow and mass transfer hinders further structural optimization and industrial application of rotating packed bed. The end-effect zone and the main packing zone are divided by probability calculation. The liquid volume mass transfer coefficient model including the end-effect zone of the rotating packed bed and the main packing zone and the cavity zone is established, that is, the three-zone liquid mass transfer model. The three-zone mass transfer model was used to predict the absorption of CO_2 by monoethanolamine (MEA), which can provide theoretical guidance for the design and application of rotating packed bed. The effects of volume flow, packing radius, liquid viscosity and surface tension on the flow pattern, droplet average diameter, droplet size, size distribution and droplet average velocity in the cavity region were investigated. The average diameter of droplets decreases with the increase of rotational speed, packing radius and liquid viscosity, and increases slightly with the increase of liquid surface tension. The initial liquid velocity has little effect on the average diameter of droplets; the size distribution of droplets conforms to R-R distribution, and the distribution index M. The average combined velocity and radial velocity of droplets increase with the increase of rotational speed and packing radius, but have little effect on the initial velocity, liquid viscosity and surface tension. (2) Based on the visualization of fluid flow in the cavity region, it is found that the mass transfer contribution in the cavity region is divided into three parts, namely, the parent droplet, the wall film and the offspring droplet. The influence of rotational speed, initial liquid velocity and packing radius on the mass transfer surface area in the cavity region was investigated by NaOH-CO_2 experimental system, and compared with the predicted value of the model. The open model can be used to describe the mass transfer surface area in the cavity region. 3. The thickness of the end effect region is calculated by probability method. Combined with the thickness of the end effect region and the results of previous theoretical studies on fluid flow and mass transfer in the packing region of rotating packed bed, the liquid volume mass transfer including the end effect region, the main packing region and the cavity region is established. Coefficient model, namely three-zone liquid-phase mass transfer model, was used to verify the error between the model value and the experimental value by NaOH-CO_2 chemical absorption experiment. It shows that the model can predict the liquid-phase mass transfer process of rotating packed bed and provide theoretical support for the design of rotating packed bed. 4. Based on the three-zone liquid-phase mass transfer model, the gas-phase mass transfer is considered simultaneously. The three-zone model was used to predict the absorption process of MEA-CO_2. The results show that most of the experimental values are in good agreement with the predicted values. The errors are within (+20%). The CO_2 absorption rate increases first and then decreases slightly with the increase of rotor speed, and increases with the increase of liquid volume flow rate and concentration of MEA. Volume volume flow decreases.
【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：TQ051.1
本文編號(hào)：2212701
[Abstract]:Chemical industry is the pillar industry of China's national economy. It provides a large number of chemicals and basic materials for China's social and economic development and national defense construction. At the same time, it produces harmful pollutants such as waste water and exhaust gas, which seriously restricts the sustainable development of China's chemical industry. The goal of the engineers is that the research and industrial application of rotating packed beds as chemical process intensification equipment will help to achieve this goal. According to the characteristics of the end-effect zone, the mass transfer in the rotating packed bed is divided into the end-effect zone, the main filler zone and the cavity zone, which are called "three zones". However, the velocity of fluid movement in the rotating packed bed is not easy to be observed, resulting in the flow pattern and flow pattern in each zone. The study of mass transfer in cavity region and end effect region, which have important influence on mass transfer in rotating packed bed, needs to be strengthened. The lag of basic research on fluid flow and mass transfer hinders further structural optimization and industrial application of rotating packed bed. The end-effect zone and the main packing zone are divided by probability calculation. The liquid volume mass transfer coefficient model including the end-effect zone of the rotating packed bed and the main packing zone and the cavity zone is established, that is, the three-zone liquid mass transfer model. The three-zone mass transfer model was used to predict the absorption of CO_2 by monoethanolamine (MEA), which can provide theoretical guidance for the design and application of rotating packed bed. The effects of volume flow, packing radius, liquid viscosity and surface tension on the flow pattern, droplet average diameter, droplet size, size distribution and droplet average velocity in the cavity region were investigated. The average diameter of droplets decreases with the increase of rotational speed, packing radius and liquid viscosity, and increases slightly with the increase of liquid surface tension. The initial liquid velocity has little effect on the average diameter of droplets; the size distribution of droplets conforms to R-R distribution, and the distribution index M. The average combined velocity and radial velocity of droplets increase with the increase of rotational speed and packing radius, but have little effect on the initial velocity, liquid viscosity and surface tension. (2) Based on the visualization of fluid flow in the cavity region, it is found that the mass transfer contribution in the cavity region is divided into three parts, namely, the parent droplet, the wall film and the offspring droplet. The influence of rotational speed, initial liquid velocity and packing radius on the mass transfer surface area in the cavity region was investigated by NaOH-CO_2 experimental system, and compared with the predicted value of the model. The open model can be used to describe the mass transfer surface area in the cavity region. 3. The thickness of the end effect region is calculated by probability method. Combined with the thickness of the end effect region and the results of previous theoretical studies on fluid flow and mass transfer in the packing region of rotating packed bed, the liquid volume mass transfer including the end effect region, the main packing region and the cavity region is established. Coefficient model, namely three-zone liquid-phase mass transfer model, was used to verify the error between the model value and the experimental value by NaOH-CO_2 chemical absorption experiment. It shows that the model can predict the liquid-phase mass transfer process of rotating packed bed and provide theoretical support for the design of rotating packed bed. 4. Based on the three-zone liquid-phase mass transfer model, the gas-phase mass transfer is considered simultaneously. The three-zone model was used to predict the absorption process of MEA-CO_2. The results show that most of the experimental values are in good agreement with the predicted values. The errors are within (+20%). The CO_2 absorption rate increases first and then decreases slightly with the increase of rotor speed, and increases with the increase of liquid volume flow rate and concentration of MEA. Volume volume flow decreases.
【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：TQ051.1
【參考文獻(xiàn)】
相關(guān)期刊論文 前10條
1 桑樂;羅勇;初廣文;鄒�？�;向陽;陳建峰;;超重力場(chǎng)內(nèi)氣液傳質(zhì)強(qiáng)化研究進(jìn)展[J];化工學(xué)報(bào);2015年01期
2 鄒海魁;初廣文;趙宏;向陽;陳建峰;;面向環(huán)境應(yīng)用的超重力反應(yīng)器強(qiáng)化技術(shù):從理論到工業(yè)化[J];中國科學(xué):化學(xué);2014年09期
3 孫潤林;向陽;楊宇成;鄒�？�;初廣文;邵磊;陳建峰;;超重力旋轉(zhuǎn)床液體流動(dòng)的可視化研究[J];高校化學(xué)工程學(xué)報(bào);2013年03期
4 孫宏偉;陳建峰;;我國化工過程強(qiáng)化技術(shù)理論與應(yīng)用研究進(jìn)展[J];化工進(jìn)展;2011年01期
5 張燕青;潘朝群;鄧先和;張一敏;;多級(jí)霧化旋轉(zhuǎn)填料床的傳質(zhì)性能[J];化工進(jìn)展;2010年02期
6 潘朝群;鄧先和;;多級(jí)霧化超重力旋轉(zhuǎn)填料床的特性及應(yīng)用[J];硫酸工業(yè);2007年06期
7 莢江霞;陳明功;張君;公茂利;陳晶靈;;碟片超重床結(jié)構(gòu)對(duì)煙道氣中CO_2脫除率的影響[J];安徽理工大學(xué)學(xué)報(bào)(自然科學(xué)版);2006年03期
8 潘朝群;張亞君;鄧先和;黃闊;;多級(jí)霧化超重力旋轉(zhuǎn)床中氣液傳質(zhì)實(shí)驗(yàn)研究[J];華南理工大學(xué)學(xué)報(bào)(自然科學(xué)版);2006年03期
9 鮑鐵虎,徐之超,計(jì)建炳,王良華,孫衛(wèi)峰;新型旋轉(zhuǎn)床性能研究[J];石油化工設(shè)備;2002年02期
10 楊玲,張鵬遠(yuǎn);旋轉(zhuǎn)床內(nèi)填料表面?zhèn)髻|(zhì)特性的研究[J];北京化工大學(xué)學(xué)報(bào)(自然科學(xué)版);2001年03期
相關(guān)博士學(xué)位論文 前3條
1 李振虎;旋轉(zhuǎn)床內(nèi)傳質(zhì)過程的模型化研究[D];北京化工大學(xué);2000年
2 竺潔松;旋轉(zhuǎn)床內(nèi)液體微�；瘜�(duì)氣液傳質(zhì)強(qiáng)化的作用[D];北京化工大學(xué);1997年
3 張軍;旋轉(zhuǎn)床內(nèi)液體流動(dòng)與傳質(zhì)的實(shí)驗(yàn)研究和計(jì)算模擬[D];北京化工大學(xué);1996年
相關(guān)碩士學(xué)位論文 前7條
1 宋銀江;超聲波耦合旋轉(zhuǎn)填充床反應(yīng)器微觀混合及傳質(zhì)性能研究[D];北京化工大學(xué);2015年
2 邢子聿;分段進(jìn)液式旋轉(zhuǎn)填充床壓降與傳質(zhì)性能研究[D];北京化工大學(xué);2013年
3 李瑜輝;超重力法脫除高濃度二氧化碳的研究[D];北京化工大學(xué);2011年
4 易飛;超重力技術(shù)脫除二氧化碳的實(shí)驗(yàn)和模擬研究[D];北京化工大學(xué);2008年
5 林海霞;定—轉(zhuǎn)子反應(yīng)器氣液傳質(zhì)及壓降特性研究[D];北京化工大學(xué);2007年
6 金漢學(xué);基于高速攝像技術(shù)的水稻芽播精密排種器研究[D];吉林大學(xué);2004年
7 燕為民;旋轉(zhuǎn)填料床氣液傳質(zhì)特性的研究[D];北京化工大學(xué);2000年
，本文編號(hào)：2212701
本文鏈接：http://sikaile.net/kejilunwen/huaxuehuagong/2212701.html
最近更新
教材專著
