CO_(2)-H_(2)O混合气体与捣固焦和顶装焦深度反应影响

Effect of CO_(2)-H_(2)Omixed gas on depth reaction of tamping coke and top charging coke

由于全球气候变暖,CO_(2)的减排逐渐成为人们关注的热点。钢铁工业作为CO_(2)排放大户,需要严格控制其CO_(2)的排放量,富氢炼铁由于具有降低碳排放的特点,已经成为冶金工艺未来发展趋势,但富氢燃料的使用会在高炉内产生大量水蒸气,所以研究高炉中不同种类焦炭与CO_(2)-H_(2)O混合气体在气化溶损反应下的变化至关重要,可以为高炉富氢冶炼条件下焦炭的选择和质量的控制提供理论依据。通过研究不同含量CO_(2)-H_(2)O气体通入管式炉中与捣固焦和顶装焦发生深度气化溶损反应,分析CO_(2)-H_(2)O混合气体中水蒸气含量变化产生的气化反应溶损差异、焦炭有机官能团和碳素结构的变化规律以及利用未反应核模型分析气化反应过程中限制性环节。研究结果表明,两种焦炭气化反应的限制性环节为界面化学反应,通过对比顶装焦和捣固焦颗粒气化溶损过程中边缘、中间、中心隙结构和相对密度上的差异发现,随着CO_(2)-H_(2)O混合气体中水蒸气含量的增加,两种焦炭表面溶损反应较其他两部分更加严重,出现了明显的开孔现象,并且捣固焦的内部开裂情况更加严重。结合FT-IR分析可知,水蒸气能够加剧气化反应过程中顶装焦和捣固焦结构内脂肪族官能团和甲基的消耗,从而导致两种焦炭的芳香度升高,同时反应后捣固焦样品中芳香烃的缩合程度增加。

With global warming in recent years,CO_(2) emission reduction has gradually become a hot spot of concern.The iron and steel industry,as a large CO_(2) emission producer,needs to strictly control its CO_(2) emissions.Hydrogen-rich ironmaking has become the future development trend of metallurgical processes due to the characteristics of reducing carbon emissions.However,the use of hydrogen-rich fuels will generate a large amount of water vapor in the blast furnace.Therefore,it is very important to study the changes of different types of coke and CO_(2)-H_(2)O mixed gas in the gasification and dissolution loss reaction,which can provide a theoretical basis for the selection and quality control of coke under the condition of hydrogen-rich smelting in blast furnace.By studying the deep gasification and dissolution reaction of tamping coke and top charging coke when gases with different CO_(2)-H_(2)O contents enter the tubular furnace,the difference of dissolution loss in gasification reaction caused by the change of water vapor content in CO_(2)-H_(2)O mixed gas was analyzed,the change law of coke organic functional groups and carbon structure was studied,and the restrictive links in the reaction process was analyzed by unreacted nuclear model.The research shows that the limiting link of the two kinds of coke gasification reaction is the interface chemical reaction.By comparing the differences of edge,middle,central gap structure and relative density in the gasification dissolution process for tamping coke and top charging coke particles,it is found that with the increase of water vapor content in CO_(2)-H_(2)O mixture gas,the surface dissolution reaction of two kinds of coke is more serious than the other two parts and there is obvious opening phenomenon.The internal cracking of tamping coke is more serious.Combined with FT-IR analysis,water vapor can aggravate the consumption of aliphatic functional groups and methyl groups in the structure of top charging coke and tamping coke during gasification reaction,resulting in the increase of aromaticity of the two kinds of coke.At the same time,the condensation degree of aromatic hydrocarbons in tamping coke samples increases after reaction.