Primary distribution of coal gas in blast furnace raceway has an important effect on blast furnace ironmaking process.The coal gas component concentration distribution was studied experimentally using a three-dimensional cold model.The results showed that CH4 concentration diminishes along with the height increasing on vertical section of raceway,and the concentration is the highest in the bottom of raceway.CH4 concentration increases gradually along the raceway depth with the lowest concentration value in front of the tuyere.The distribution of CH4 concentration has different characteristics in different raceway zones.
ZHANG Sheng-fu WEN Liang-ying BAI Chen-guang QIU Gui-bao HU Mei-long LU Xue-wei
In order to establish correlativity between pulverized coal combustion in a blast furnace raceway and its radiant image, we investigated the relationships between two dimensional radiant images and three dimensional radiant energy in a blast furnace raceway, focusing on the correlativity of the numerical simulation of combustion processes with the connection of radiant images information and space temperature distribution. We calculated the uneven radiate characteristic parameterby taking radiant images as a kind of radiative boundary for numerical simulation of combustion processes, and put forward a method to examine three-dimensional temperatures distribution in blast furnace raceway by radiant image processing. The numeral temperature fields matching the real combustion can be got by the numeric image processing technique.
The two-dimensional steady-state discrete phase mathematical model is developed to analyze gas-particle flow and combustion characteristics of coal particles,as well as components concentration and temperature distribution of coal gas in the process of pulverized coal injection of blast furnace raceway.The results show that a great deal of coal gas discharges on the top of raceway away from the tuyere,and the residence time of coal particles in the region of blowpipe and tuyere is 20 ms or so and 50 ms when it reaches raceway boundary.The pressure is the highest at the bottom of raceway and the maximal temperature is about 2423 K.The char combustion is mainly carried out in the raceway and the maximum of char burn-out rate attains 3×10-4 kg/s.
ZHANG Sheng-fu BAI Chen-guang WEN Liang-ying QIU Gui-bao LU Xue-wei
