焦炭在H2O+CO2气氛中的溶损反应特性

 为了研究富氢高炉内焦炭的溶损反应特性,开发了连续进水的全自动焦炭反应性测定装置,分别利用CO₂和N₂载带不同比例H₂O(0%～30%)提供H₂O+CO₂(H₂O和CO₂混合气体)和H₂O+N₂(H₂O和N₂混合气体)的含水气氛进行焦炭溶损试验,通过红外气体分析仪实时记录出口气体中CO和H₂的摩尔分数,研究了焦炭在H₂O+CO₂气氛下的溶损反应过程以及碳溶反应(C+CO₂=2CO)和水煤气反应(C+H₂O=CO+H₂)的动力学过程。研究表明,随着H₂O+CO₂混合反应气氛中H₂O比例的增加,焦炭的碳素溶损率和溶损速率均逐渐增大,而且水煤气反应的溶损速率逐渐变大、碳素溶损率逐渐升高,但是碳溶反应的溶损速率则逐渐减小、碳素溶损率也逐渐降低,这说明H₂O+CO₂反应气氛中H₂O和CO₂同时与焦炭反应存在显著的竞争作用。通过分析碳素溶损率和水蒸气含量线性关系的拟合斜率发现,焦炭在H₂O+CO₂混合反应气氛中发生的碳溶反应和水煤气反应的斜率均小于单纯单一气氛下的碳溶反应和水煤气反应的斜率,并提出基于斜率差值的抑制因子α表征H₂O和CO₂对碳溶反应和水煤气反应互相影响程度,CO₂对水煤气反应的抑制因子α_<sub>CO₂/H₂O为0.253,H₂O对碳溶反应的抑制因子α_<sub>H₂O/CO₂为0.179,α_<sub>CO₂/H₂O为α_<sub>H₂O/CO₂的1.41倍,CO₂对水煤气反应的抑制程度强于H₂O对碳溶反应的抑制程度。

Solution loss characteristics of cokes in H2O+CO2 atmosphere

To study the solution-loss reaction characteristics of cokes in hydrogen-rich blast furnace, a homemade coke reactivity measurement device with continuous water inflow was developed to carry out coke solution-loss experiments by CO₂ (N₂) carrying H₂O vapor with different percentages (0-30%), which provided H₂O+CO₂(gas mixture of H₂O and CO₂)and H₂O+N₂(gas mixture of H₂O and N₂)atmosphere. The Boudouard reaction(C+CO₂=2CO)kinetics and water gas (C+H₂O=CO+H₂)reaction kinetics of cokes in H₂O+CO₂ atmosphere were studied using real-time recording the mole percent of CO and H₂ in the outlet gas through infrared gas analyzers. The results show that carbon loss ratio and solution-loss rate of cokes increase with the increase of H₂O percentage in the H₂O+CO₂reaction atmosphere. Furthermore, with the increase of H₂O percentage the water gas reaction rate and carbon loss ratio increase gradually, while the Boudouard reaction rate and carbon loss ratio decrease gradually, which indicates that there is a strong competition between the reactions of H₂O and CO₂ with coke. The analysis for fitting slopes of linear relationship between carbon loss rate and H₂O percentage shows that the slopes of the Boudouard reaction and water gas reaction for cokes in H₂O+CO₂ atmosphere are less than the ones in single atmosphere, and an inhibition factor (α) based on the difference of reaction rate constant is proposed to evaluate the degree of inhibition, which can characterize the influence degree of interaction for H₂O and CO₂ on carbon dissolution reaction and water gas reaction. The inhibition factor α_<sub>CO₂/H₂O of CO₂ to water gas reaction is 0.253, and the inhibition factor α_<sub>H₂O/CO₂of H₂O to Boudouard reaction is 0.179. α_<sub>CO₂/H₂O: α_<sub>H₂O/CO₂ is 1.41. The inhibition degree of CO₂ on water gas reaction is stronger than that of H₂O on carbon solution reaction.