气体非等摩尔扩散对焦炭溶损反应的影响

焦炭作为重要的炼铁原料,其热态性能的优劣备受关注.而同一种焦炭使用不同热性质评价体系(CRI、CSR、CRR25、CSR25)得到的结果可能完全不同,根源在于对焦炭溶损反应机理的认知不够深入全面.焦炭发生溶损反应过程中,气体非等摩尔扩散这一因素常常被忽略,导致对焦炭溶损反应机理的认知出现偏差.为了能够更加清晰全面地了解...

Influence of gas non-equimolar diffusion on coke solution-loss reaction

As an important raw material for ironmaking, coke has attracted much attention in terms of its thermal properties. The results obtained by different thermal property evaluation methods (CRI, CSR, CRR₂₅, CSR₂₅) for the same coke may be completely different, which is due to the lack of in-depth and comprehensive understanding of coke solution-loss reaction mechanism. In the process of coke solution-loss reaction, the factor of gas non-equimolar diffusion is always ignored, which leads to the deviation in understanding of coke solution-loss reaction mechanism. In order to understand the coke solution-loss reaction mechanism more clearly and comprehensively, a kinetic model considering gas non-equimolar diffusion was established.The gasification experiments of industrial coke and CO₂ with 25% solution-loss at 1 100-1 300 ℃ were carried out. The effect of gas non-equimolar diffusion on coke solution-loss reaction was explained by comparing the CO₂ effective internal diffusion coefficient, the effective area of CO₂ concentration in coke and the reaction controlling step with and without consideration of gas non-equimolar diffusion. The results show that with considering the gas non-equimolar diffusion, the CO₂ effective internal diffusion coefficient decreases and changes with temperature, reaction process and internal radius of coke. With increase of temperature, the effective area of CO₂ concentration in coke decreases, as well as the opening, area and position, and it is closer to the coke surface, meanwhile, the region of solution-loss reaction decreases. The reaction controlling step has no obvious variation trend and remains stable with the reaction process.