高炉风口回旋区兰炭燃烧行为的数值模拟

为了探究价格较为廉价并且燃烧性能良好的燃料(兰炭)在高炉直吹管、风口、回旋区内燃烧产生的温度、气体成分以及燃料的燃尽率分布情况,根据高炉的实际尺寸,建立了三维物理模型并进行模拟计算。模拟结果表明,当单独喷吹烟煤、兰炭时,回旋区内的温度均为先升高到最高温度后缓慢降低,风口中心线上最高温度分别为2 447、2 415 K。然而,当单独喷入无烟煤、焦化除尘灰(CDQ粉)时,回旋区内温度持续缓慢上升,在回旋区出口处达到的最高温度分别为2 473、2 366 K。烟煤在风口、回旋区内燃烧产生CO的质量分数均高于其他3种燃料;兰炭、烟煤、无烟煤、CDQ粉在回旋区出口处产生的CO质量分数分别为20.82%、26.09%、17.51%、15.74%。采用兰炭喷吹的燃尽率(63.01%)高于采用无烟煤和CDQ粉的燃尽率(分别为58.03%和52.40%),低于采用烟煤的燃尽率(73.13%)。虽然兰炭和无烟煤的组成成分相似,但是从兰炭在风口、回旋区内燃烧产生的温度、气体成分、燃尽率等方面来看,兰炭的燃烧性能要强于无烟煤。

Numerical simulation of combustion behavior forsemi-coke in raceway of blast furnace

In order to explore the distribution of temperature, gas composition and fuel burnout generated by the combustion of cheaper fuel (semi-coke) with good combustion performance in the blowpipe, tuyere, and raceway of the blast furnace, a three-dimensional physical model was established based on the actual size of blast furnace and simulation was carried out. The simulation results show that the temperature in the raceway first increases to the highest temperature and then slowly decreases as the bituminous coal and semi-coke are injected separately. The highest temperatures on the center line of tuyere are 2 447 K and 2 415 K respectively. However, the temperature in the raceway continues to rise when anthracite and CDQ powder are injected separately and the highest temperatures at the exit of raceway are 2 473 K and 2 366 K respectively. The mass fraction of CO produced by bituminous coal combustion in the tuyere and raceway is higher than that of the other three fuels. The CO mass fractions of semi-coke, bituminous coal, anthracite and CDQ powder at exit of raceway are 20.82%, 26.09%, 17.51% and 15.74% respectively. The burnout of semi-coke injection (63.01%) is higher than that of anthracite and CDQ powder (58.03% and 52.40%, respectively), and lower than that of bituminous coal (73.13%). Although the composition of semi-coke is similar to that of anthracite, the combustion performance of semi-coke in the tuyere and raceway is better than that of anthracite from the perspective of temperature, gas composition, burnout generated by the combustion.