Fe-K/AC催化氧化脱硫剂制备及反应机理研究

采用正交实验法制备了负载铁、钾的活性炭(Fe-K/AC)热煤气催化氧化脱硫剂,考察了活性组分铁、钾含量、二价铁和三价铁比例、煅烧温度对催化氧化脱硫反应活性的影响。由正交实验极差分析可知,各因素影响程度依次为:钾含量>铁含量>煅烧温度> Fe²⁺/Fe³⁺,最优制备条件为,铁含量0.5%、钾含量5.0%、煅烧温度600 ℃、Fe²⁺/Fe³⁺比0.5。通过对脱硫剂的孔隙结构和表面形貌分析可知,活性炭表面负载的铁金属氧化物具有催化氧化硫化氢生成单质硫的活性,碱金属氧化物具有协同作用,可以改变表面酸碱性,促进硫化氢的催化转化,但过高的金属氧化物负载量会阻塞孔道,减小反应比表面积,从而降低脱硫剂的反应活性。

Preparation and mechanism of Fe-K/AC for catalytic oxidation of hydrogen sulfide

Modified activated carbon Fe-K/AC(activated carbon supported iron and potassium) was used as an oxidation catalyst for low concentration hydrogen sulfide(H2S) removed.The orthogonal design method was introduced in the research of Fe-K/AC preparation to determine the optimum condition and to measure the impact of different factors.Then,catalytic activity and mechanism on Fe-K/AC catalyst for oxidation of hydrogen sulfide was investigated.The optimum preparation condition of Fe-K/AC with high sulfur capacity and selectivity is that the iron and potassium content is 0.5% and 5.0%,respectively;and the calcination temperature and the Fe2+/Fe3+ atomic ratio is 600 ℃ and 0.5,respectively.The order of their influences is potassium content > iron content > calcination temperature > Fe2+/Fe3+ atomic ratio.Results from structural parameters and surface morphology of sorbents reveal that iron metal oxide loaded on the surface of activated carbon has the selective catalytic oxidation activity of hydrogen sulfide to element sulfur.Alkali metal oxide,which changes basic surface groups,has a synergistic effect on the catalytic oxidation of hydrogen sulfide.However,the catalytic activity decreases due to excessive metal oxides loadings that may block the accessibility of micropores and reduce the surface area.