垃圾焚烧炉低温腐蚀机理的分子动力学模拟

Molecular Dynamics Simulation of Low Temperature Corrosion Mechanism of Waste Incinerator

针对垃圾焚烧系统中换热器表面低温腐蚀的问题,通过分子动力学的研究方法模拟了硫酸分子在镍金属涂层表面的腐蚀过程,建立了腐蚀过程模型,对比了不同涂层的腐蚀速率。研究表明:H_(2)SO_(4)分子在镍金属涂层表面先解离出2个氢氧根离子,分解出的O—H离子与O—S—O离子分别被Ni金属表面捕获,其中仅O—H离子中的O与Ni原子形成键链;对比氧化铝、镍金属和镍铬合金3种涂层,镍铬合金对结低温腐蚀的抑制效果最好,镍金属涂层抑制效果最差,即选用抗氧化性强的涂层材料可有效减少垃圾焚烧系统受热面表面低温腐蚀的现象。

Aiming at the problem of low temperature corrosion on the surface of the heat exchanger in the waste incineration system,the corrosion process of sulfuric acid molecules on the surface of nickel alloy coatings was simulated by molecular dynamics research methods,the corrosion rates of different coatings were explored,and the corrosion process model was established.The results showed that H_(2)SO_(4) dissociates two hydroxide ions on the surface of nickel metal coating,and the decomposed O—H ions and O—S—O ions were captured by the surface of Ni metal seperatively.O in O—H ions forms bond chains with Ni atoms only.Compared with aluminum oxide,nickel alloy and nickel chromium alloy,nickel chromium alloy had the best inhibition effect on the initial slagging layer,while nickel alloy coating had the worst inhibition effect.The selection of coating materials with strong oxidation resistance could effectively reduce the phenomenon of low temperature corrosion on the surface of the heating surface of the waste incineration system.