Improving the combustion efficiency of solid fuels is important for reducing carbon monoxide emissions in the iron ore sintering process. In this paper, the surface steam spraying technology is introduced in the sintering process based on the auxiliary combustion effect of steam on coke, and its potential to reduce carbon monoxide emissions is demonstrated. Thermogravimetric analysis experiments of coke breeze in air and air-steam mixed atmosphere are carried out, and the results show that the introduction of steam can reduce the concentration of carbon monoxide in the exhaust gas from 183×10-6 to 78×10-6. At the same time, the mechanisms of carbon monoxide emission reduction by surface steam spraying technology are analyzed from the thermodynamic and kinetic perspectives. Then, a series of laboratory-scale sintering pot tests are carried out under no spraying operation, interval spraying operation, and continuous spraying operation. The results indicate that both interval and continuous spraying operations can reduce carbon monoxide emissions. The optimal mode of steam spraying under the present experimental conditions is continuously spraying for 13 min at a volume rate of 0.053 m3/min. Compared with no spraying, the average carbon monoxide concentration in the exhaust gas is reduced from 7565×10-6 to 6231×10-6, and total carbon monoxide emissions for per ton sinter are reduced from 13.46 m3/t to 9.51 m3/t.
提高固体燃料的燃烧效率对减少铁矿石烧结过程中的一氧化碳排放具有重要意义。本研究借助蒸汽对焦炭燃烧的辅助作用, 在烧结过程中引入表面蒸汽喷吹技术, 并验证了该技术在降低一氧化碳排放方面的潜力。首先, 在空气与空气-蒸汽混合气氛中分别进行焦炭的热重实验。结果表明, 相比于空气气氛, 引入蒸汽后的混合气氛可使燃烧废气中的一氧化碳浓度从183×10−6降低到78×10 −6。此外, 从热力学和动力学角度分析了表面蒸汽喷吹技术减少一氧化碳排放的机理。然后, 在无喷吹、间隔喷吹与连续喷吹操作下, 进行了一系列实验室规模下的烧结杯试验。结果表明, 间隔喷吹和连续喷吹均可降低烧结过程中的一氧化碳排放。在本试验条件下, 蒸汽喷吹的最佳方式为以0.053 m3/min 的喷吹流量连续喷吹13 min。与无喷吹案例相比, 烧结废气中一氧化碳的平均浓度从7565×10 −6降低到6231×10−6, 烧结矿的一氧化碳总排放量则从13.46 m3/t 降低到9.51 m3/t。.
Keywords: carbon combustion; carbon monoxide; emission reduction; sintering; steam spraying.
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