过渡金属离子液相催化氧化低浓度烟气脱硫

来源期刊：中南大学学报(自然科学版)2003年第5期

论文作者：朱德庆 潘建 潘润润

文章页码：489 - 493

关键词：二氧化硫烟气;过渡金属离子;液相催化氧化脱硫;环境保护

Key words：flue gas of SO₂ concentration; transition metal ions; liquid catalyzed oxidation desulphurization; environment protection

摘    要：对Mn²⁺,Fe²⁺,Zn²⁺ 3种过渡金属离子液相催化氧化低浓度烟气脱硫的效果进行了对比,并对Mn²⁺液相催化氧化烟气脱硫的相关工艺参数进行了优化;运用溶液化学原理,对SO₂及Mn²⁺在溶液中的组分进行了计算,研究了Mn²⁺液相催化氧化烟气脱硫的机理.研究结果表明:Mn²⁺,Fe²⁺和Zn²⁺ 3种过渡金属离子对烟气脱硫都有催化作用,Mn²⁺的催化效果最佳;在烟气中,当SO₂体积分数为1.4%,O₂体积分数为10%,烟气流量为140 L/h,吸收液体积为200 mL,温度为24℃,吸收液pH为5~6及吸收液中Mn²⁺浓度为0.15 mol/L时,经过一段吸收反应,SO₂转化率大于80%,烟气脱硫率大于75%;当吸收液pH=5~6时,锰主要以Mn2+形式存在,SO₂主要以HSO₃^-的形成存在;其催化反应的机理为:Mn²⁺与HSO₃^-反应形成络合物,成为反应链的引发剂来诱发氧化反应.

Abstract: The effect of three kinds of transition metal ions Mn²⁺, Fe²⁺and Zn²⁺on the liquid catalyzed oxidation desulphurization of flue gas of low SO₂concentration was studied. The optimization of the process parameters of catalyzed oxidation desulphurization by Mn²⁺was carried out, which includes volumetric fraction of SO₂ and O₂, and flow rate of flue gas, pH value , volume and concentration of Mn²⁺of absorbent liquid. Based on the aqueous chemistry theory, the composition of SO₂ and Mn²⁺in aqueous is determined, and the mechanism of Mn²⁺catalysis oxidation desulphurization in liquid is demonstrated. The results show that the three ions can all catalyze the desulphurization of flue gas in solutions, but manganese ion is the best. When the flue gas containing(volume fraction) 1.4% SO₂ and 10% O₂ at 140 L/h flow rate was desulphurized by absorbent solution at pH 5~6 and 0.15 mol/L Mn²⁺, above 80% of the transformation rate of SO₂ into SO₃and 75% of desulphuriation rate were achieved only once. The results of aqueous-chemistry calculation reveal that the mainly existing composition of manganese ion and SO₂ are Mn²⁺and HSO₃^-, respectively, at pH 5-6 of absorbent solution. The catalysis mechanism of Mn²⁺ is that Mn²⁺ triggers the oxidation of SO₂ to occur by forming a complex with HSO₃^-, which induce a chain of oxidation reactions in the solution.