摘要
针对再生铝熔炼过程中二噁英(PCDD/Fs)的生成与抑制问题,通过热力学-动力学耦合模型揭示了其生成机理与优化路径。热力学分析表明,二噁英在300~400℃温度范围内的吉布斯自由能最低(ΔG=-85.6 kJ/mol),且烟气停留时间超过2 s时生成速率呈指数增长。基于自由基链式反应理论,构建了包含前驱物合成与钙基抑制的动力学模型,量化了氯含量[Cl^(-)]、氧分压[O_(2)]及催化剂浓度的影响规律。通过案例验证,集成X射线分选、富氧燃烧与纳米CaO添加的多级抑制技术可使二噁英生成速率降低40%,峰值浓度从4.52×10^(3)降至2.71×10^(3)ng-TEQ/kg。进一步提出动态氧浓度调节与复合催化剂改性等优化方向,为工业应用提供理论支撑。
Aiming at the generation and inhibition of dioxins(PCDD/Fs)during the smelting process of recycled aluminum,the thermodynamic-kinetic coupling model was used to reveal the generation mechanisms and optimization pathways.Thermodynamic analysis showed that the Gibbs free energy was the lowest(ΔG=-85.6 kJ/mol)in the temperature range of 300 to 400℃,and the generation rate increased exponentially when the flue gas residence time exceeded 2 s.Based on the theory of radical chain reactions,a kinetic model incorporating precursor synthesis and calcium-based inhibition was constructed to quantify the effects of chloride content[Cl^(⁻)],oxygen partial pressure[O_(2)],and catalyst concentration.Case studies had validated that the multi-stage inhibition technology integrating X-ray sorting,oxygen-enriched combustion and nano-CaO addition could reduce the dioxin generation rate by 40%,with peak concentrations decreasing from 4.52×10^(3)to 2.71×10^(3)ng·TEQ/kg.Further proposes optimization directions such as dynamic oxygen concentration regulation and composite catalyst modification to provide theoretical support for industrial applications.
作者
张铭守
ZHANG Mingshou(Chinalco Ruimin Co.,Ltd.,Fuzhou 350000,Fujian,China)
出处
《热处理技术与装备》
2025年第3期62-65,共4页
Heat Treatment Technology and Equipment
关键词
再生铝熔炼
二噁英
热力学-动力学耦合模型
多尺度优化
recycled aluminum smelting
dioxin
thermodynamic-kinetic coupling model
multi-scale optimization
