Pulverized coal combustion in high temperature air

1. Background / Objective

These days iron becomes more essential for our life because they are used for buildings, automobiles, household electronic appliances and so on. Manufacturing of iron starts with reduction of iron ore and 95% of this process is conducted in the blast furnace [1]. High temperature air and pulverized coal are used as auxiliary reduction agent and they are injected into blast furnace through tuyere which is located on the foot of furnace. For more efficiency, it’s important to finish the combustion earlier and form the reduction gas such as CO. So we need to grasp spatial distribution of chemical species and gas temperature precisely but direct measurement can’t be applied due to high temperature, hence we use numerical simulation. Precise boundary condition of tuyere is necessary for improving the numerical simulation of blast furnace. Therefore we build the numerical simulation of tuyere.


Fig.1 : Tuyere in blast furnace

2. Research methodology

In our previous research we fabricated experimental apparatus which imitate the tuyere and investigated the ignition characteristics of pulverized coal with variation of coal feeding rate and carrier air flow rate. We observed OH-radical chemiluminescence which appears at early phase of combustion and then got ignition point. We compare this data with simulated result to improve the code. In numerical simulation we solve turbulent flow model with Large Eddy Simulation (LES) and for comparison, we use results of concentration distribution and reaction rate distribution of chemical species such as CO and Tar which are generated in early phase of reaction


Fig.2 : Schematic diagram of experimental apparatus