高炉喷吹富氢燃料对高炉冶炼过程的影响

Effects of hydrogen-rich fuels injection on blast furnace ironmaking process

为降低高炉炼铁碳排放,基于物料平衡和热平衡,分析了高炉风口喷吹天然气、焦炉煤气、氨气、氢气这4种富氢或纯氢燃料时的热力学行为,考察了富氢气体置换比、预热温度、喷吹量及富氧率对高炉主要指标的影响。结果表明,提高鼓风富氧率可降低炉腹煤气量且快速提高理论燃烧温度,提高富氢气体预热温度可明显提高理论燃烧温度而对炉腹煤气量无影响,提高置换比则可降低炉腹煤气增加量甚至使其低于基准煤气量、但对理论燃烧温度影响不明显。在维持煤气高温热量不变时,喷吹单位富氢气体所需富氧率从高至低依次为天然气、焦炉煤气、氢气、氨气,且其随着富氢气体喷吹量增加或减少取决于富氢气体置换比。高置换比及高富氧条件有利于天然气喷吹量增加,而不同置换比下喷吹氨气均需降低富氧率方可维持煤气高温热量不变。该研究可为高炉喷吹适宜的富氢燃料提供理论支持。

To reduce carbon emission in the ironmaking process of blast furnace,thermodynamic behaviors of hydrogen-rich or pure hydrogen fuels,i.e.natural gas,coke oven gas,ammonia gas and hydrogen gas,during injection into blast furnace tuyeres were analyzed.The effects of hydrogen-rich gas replacement ratio,preheating temperature,injection volume,and oxygen enrichment ratio on the main indicators of blast furnace were investigated based on material and thermal balances.Results show that increasing oxygen enrichment ratio of blast can reduce belly gas volume,and significantly increase theoretical combustion temperature.Though preheating of hydrogen-rich gas can significantly increase theoretical combustion temperature,but has no obvious effect on belly gas volume.Increasing the replacement ratio can decrease the increment of belly gas volume even to a level lower than the reference value,but exerts no significant influence on theoretical combustion temperature.To maintain constant thermal energy of belly gas,the required oxygen enrichment ratio for injecting hydrogen-rich gas per volume ranging from high to low is natural gas,coke oven gas,hydrogen gas,and ammonia gas.Whether it increases or decreases with the increasing of gas injection depends on the replacement ratio.High replacement ratio and oxygen enrichment ratio are conducive to the increase of natural gas injection volume,whereas ammonia gas needs to lower the oxygen enrichment ratio to maintain the constant high-temperature gas thermal energy under different replacement ratios.This study can provide theoretical support for determining suitable hydrogen-rich fuels of blast furnace.