高校化学工程学报
高校化學工程學報
고교화학공정학보
JOURNAL OF CHEMICAL ENGINEERING OF CHINESE UNIVERSITIES
2013年
6期
952-959
,共8页
微反应器%传递过程%多孔介质%Villermaux/Dushman反应%离集指数
微反應器%傳遞過程%多孔介質%Villermaux/Dushman反應%離集指數
미반응기%전체과정%다공개질%Villermaux/Dushman반응%리집지수
micro-channel reactor%mass transfer%porous medium%Villermaux-Dushman reaction%segregation index
针对Villermaux/Dushman反应体系，研究套管式微反应器内错流流动与反应传质过程。采用雷诺平均湍流传递方程描述流体区的传递过程，由达西模型确定丝网区的流动阻力。研究获得反应器内组分分布、有效扩散速率分布以及流体在丝网内的停留时间分布特征，发现在套管式微反应器内存在两个决定组分在丝网区浓度扩散分布规律的关键因素，丝网内流体停留时间分布和环隙内错流流动效应。相同进料比下，随着总雷诺数的增大，离集指数在整体呈下降的趋势下存在一转折点，雷诺数较小时组分扩散受分子扩散和湍流扩散控制，停留时间较长，副产物生成较多，离集指数受雷诺数的影响较大；当总雷诺数大于491后，错流流动起主要作用，组分扩散主要受湍流扩散控制，停留时间小于0.02 s，副产物生成较少，离集指数基本不随雷诺数变化。
針對Villermaux/Dushman反應體繫，研究套管式微反應器內錯流流動與反應傳質過程。採用雷諾平均湍流傳遞方程描述流體區的傳遞過程，由達西模型確定絲網區的流動阻力。研究穫得反應器內組分分佈、有效擴散速率分佈以及流體在絲網內的停留時間分佈特徵，髮現在套管式微反應器內存在兩箇決定組分在絲網區濃度擴散分佈規律的關鍵因素，絲網內流體停留時間分佈和環隙內錯流流動效應。相同進料比下，隨著總雷諾數的增大，離集指數在整體呈下降的趨勢下存在一轉摺點，雷諾數較小時組分擴散受分子擴散和湍流擴散控製，停留時間較長，副產物生成較多，離集指數受雷諾數的影響較大；噹總雷諾數大于491後，錯流流動起主要作用，組分擴散主要受湍流擴散控製，停留時間小于0.02 s，副產物生成較少，離集指數基本不隨雷諾數變化。
침대Villermaux/Dushman반응체계，연구투관식미반응기내착류류동여반응전질과정。채용뢰낙평균단류전체방정묘술류체구적전체과정，유체서모형학정사망구적류동조력。연구획득반응기내조분분포、유효확산속솔분포이급류체재사망내적정류시간분포특정，발현재투관식미반응기내존재량개결정조분재사망구농도확산분포규률적관건인소，사망내류체정류시간분포화배극내착류류동효응。상동진료비하，수착총뢰낙수적증대，리집지수재정체정하강적추세하존재일전절점，뢰낙수교소시조분확산수분자확산화단류확산공제，정류시간교장，부산물생성교다，리집지수수뢰낙수적영향교대；당총뢰낙수대우491후，착류류동기주요작용，조분확산주요수단류확산공제，정류시간소우0.02 s，부산물생성교소，리집지수기본불수뢰낙수변화。
This paper presents a numerical simulation of the Villermaux-Dushman fast parallel competing reaction in a new microporous tube-in-tube microchannel reactor (MTMCR) for the study of the characteristics of the process in MTMCR with cross-flow flow and mass transfer. Darcy law was applied to describe the porous flow in the wire mesh structure. The characteristic patterns of components distribution, the effective diffusion coefficient and the residence time in the mesh structure were obtained and it was found that there are two key factors which decide the distribution of components in the mesh structure, i.e. the residence time distribution in the mesh structure and the cross flow in the annular space. As the total Reynolds number increases, there is a transition point in the segregation index curve, which appears an overall downward trend. Under the same feed ratio, when the flow rate is low, both the molecular diffusion and the turbulent diffusion play the major roles. More byproduct is produced if the residence time is long and the segregation index decreases with the increase of Reynolds number. When the Reynolds number is beyond 491, the turbulence of the cross flow becomes much important, and the residence time is below 0.02 s, at the same time, less byproduct is produced and the segregation index basically remains constant.
