Research On The Micro Scale Mass Transfer And Chemical Reactions

Compared with the traditional scale fluid, micro scale fluid has a unique advantage. In recent years, researchers have designed a series of micro equipment which has a typical representative named as micro reactor, in order to achieve the fluid flow and reaction in micro scales. But research about the fluid flow characteristics and reaction characteristics in micro scales is still in its infancy, need lots of research and theory to develop the micro scale chemical technology.This article use the micro porous tube-in-tube micro-channel reactor as a object reactor, build the physical model and calculation model depend on the ANSYS CFX, and use the Villerrnaux/Dushman reaction system to study the micromixing efficiency basic standard on the experimental date, to analysis the mass transfer and chemical reaction process in the micro porous tube-in-tube micro-channel reactor. Research found that, components in annular space diffused to the mesh structure, and formed two different concentration diffusion domains, and the reaction almost took place in the mesh structure. The factors affected the segregation index can be classified into two varieties, one was the residence time in the mesh structure which affect the reaction time, and the other was the turbulent diffusion which affect the concentration diffusion. Under the same feed ratio, the influence of Reynolds number on the Segregation index basically met the trend of decrease with the increase of Reynolds number, and there was a transition point in the Segregation index curve, when Re<491, Re has a significant impact on Xs, and when Re>491, Re has a much more smaller affect on Xs, and the Xs was less than0.0005when Re>2578, almost implement micromixing completely.We also studied the effect of structure parameter to the mass transfer and reaction process, found that:both decreased the annular space, porosity and width of mesh structure can reduce the segregation index, which mean that, improve the micromixing efficiency. Extraordinary, in the case of annular space was0.5mm, and the mesh structure width was5mm, we could basically control the concentration diffusion, changed the order of main body mixing and reaction in the system, and made the reaction happen in the annular space, which achieved the theory design requirements, we also found that decrease the mesh structure thickness can improve the micromixing efficiency within limits.