高爐中移動堆料床與氣體流場分析

煉鐵工業中，最重要的部分為鐵水來源的高爐製程，過去大多以技師的經驗與技術為依據，若技術交接無法順利傳承給新進技術人員，那麼煉鐵品質將會有所落差，所以現在需要對於高爐製程的內部運作做進一步的瞭解進而對高爐操作參數加以控制。高爐是一個複雜的反應器，爐內具有化學反應與相變化，在此先不考慮化學反應的作用與相變化，主要的探討的內容為固體物料向下滑移情形與氣體在堆料床的流場現象。將高爐內移動的固體堆料床以描述連續體的流體力學方程式加以探討，本文應用Eulerian-Eulerian二相流模型，探討固體與氣體的逆相流行為。而此處固體顆粒之間的作用力除了流體力學中的暫態項與對流向之外再加上動力學中的碰撞效應所造成的摩擦力以及正向力造成的固體壓力關係加以探討。兩相流中的阻力係數應用流體化床領域的Ergun’s equation來探討氣體流經向下移動中的堆料床所造成的作用力。計算工具為商用軟體ANSYS-CFX，其計算方法為有限體積法，使用SIMPLE與Rhie-Chow的修正方法獲得速度與壓力修正數值，本文模擬高爐內穩態的行為並進一步探討在不同固體顆粒大小分佈的狀態下，對於高爐中固體移動與氣體流場的變化情形產生的影響，做為未來進一步探討高爐內部化學反應及相變化的基礎。

關鍵字

高爐；逆相流；二相流

並列摘要

Blast furnace plays an important process in the fountainhead of iron and steel industry. In the past, the manufacture process is depending on the technician’s experience and skill. If the guidance of skill is not successfully to make the new technicians understand, the property of steel production will be poor. Nowadays we have to understand the phenomenon inside of blast furnace in order to control the process of steel production. Blast furnace is a complicated reactor which contains chemical reaction and phase transfer. We don't consider the chemical reaction and phase transfer in blast furnace in this research but focus on the motion of solid particles descending and the phenomenon of gas flow in the packed bed. The moving packed bed is discussed by the continuity equation of fluid dynamic. It uses the Eulerian-Eulerian two phase model to discuss the phenomenon of countercurrent flow. It doesn't only discuss the transient and convection part of fluid dynamics but also discuss the particle interaction which is effected by solid collision. The solid collision is from kinetics theory and the effect of solid collision produces the normal force and friction. The drag force between descending packed bed and gas flow is discussed by the drag coefficient of Ergun's equation. The calculation tool is ANSYS-CFX and the numerical method is finite volume method. It uses implicit method to calculate the steady state flow and use the correction method of SIMPLE and Rhie-Chow to obtain the corrected result. This simulation is to discuss the effect of descending solid and gas flow under the different distribution of diameter. It provides the base of further discussion of chemical reaction and phase transfer of blast furnace.

並列關鍵字

blast furnace ； countercurrent flow ； two phase flow

參考文獻

[1] J. Yagi and I. Muchi, “Theoretical estimations on the longitudinal distributions of process variables in blast furnace and it’s productivity”,

Trans Iron Steel Inst. Jpn., 10, 392 (1970)

[2] T. Sugiyama and M. Sugata, “Development of two dimensional mathematical model for the blast furnace”, Nippon Steel Tech.Rep., 35,

[3] J. Chen and T. Akiyama, “Modeling of solid flow in moving bed”, ISIJ Int., 6, 664 (1993)

[4] Jun Ichiro Yagi, “Mathematical modeling of the flow of four fluids in a packed bed”, ISIJ Int., 33, 619 (1993)

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高爐中移動堆料床與氣體流場分析

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