( 1. 東北大學(xué) 資源與土木工程學(xué)院， 沈陽 110004；
2. 東北大學(xué) 材料與冶金工程學(xué)院，沈陽 110004)
摘 要: 考慮到冶金固定床是顆粒堆積的松散多孔介質(zhì)， 首先將單一顆粒的動力學(xué)方程推廣到多顆粒的微元體上， 導(dǎo)出了化學(xué)反應(yīng)項的具體形式， 建立了冶金固定床一維對流、 反應(yīng)、 擴散方程， 然后求出其解析解； 通過實例計算分析主氣流中反應(yīng)氣體的濃度分布。 結(jié)果表明： 顆粒大小和孔隙率對反應(yīng)進(jìn)程有很大的影響， 其影響可以用Thiele數(shù)和Peclet數(shù)定量衡量； 微元體的反應(yīng)類型不等于反應(yīng)器的反應(yīng)類型； 化學(xué)反應(yīng)速率對反應(yīng)氣體濃度的影響超過對流速度， 而擴散的影響最小； 微元體的綜合反應(yīng)速率、 對流速度以及反應(yīng)器的長度本身是影響反應(yīng)器反應(yīng)類型的重要因素。
關(guān)鍵字: 顆粒動力學(xué)； 微元體動力學(xué)； 化學(xué)反應(yīng)； 對流； 擴散； 解析解
（ 1. School of Resource and Civil Engineering,
Northeastern University, Shenyang 110004, China;
2. School of Material and Metallurgy,
Northeastern University, Shenyang 110004, China）
Abstract: In view of the fact that fixed bed is porous media of granule aggregation, the dynamics of a single particle is extended to the dynamics of representative-element volume including multiple particles, so that the more exact chemical reaction term can be deduced. Then one-dimensional model for instable convection, chemical reaction and diffusion in fixed bed is proposed and solved analytically. Computation cases show that the scale of pellet and the porosity of bed have great impact on the reaction process taking place in reactor, which can be measured by Thiele module and Peclet module, the reaction behavior of REV is not the same as that of reactor. For the gas concentration, chemical reaction has greater impact than convection has, because Thiele module is proportional positively to L2/D and Peclet module is to L/D, and diffusion has the least impact. The overall rate of REV, length of reactor itself and convection all contribute remarkably to the performance of reactor.
Key words: dynamics of single particle; dynamics of representative-element volume; chemical reaction; convection and diffusion; analytical solution
