【作者】 潘志爽；

【导师】 马智；

【作者基本信息】 天津大学 ， 工业催化， 2007， 硕士

【摘要】 随着现代工业的发展,大量的SO₂排放到大气中,造成了世界范围内越来越严重的酸雨现象。如何治理SO₂带来的危害,已经引起了各国政府和企业的重视。与其它治理方法相比较,采用CO催化还原脱除SO₂具有许多优点,如回收硫资源,无二次污染等。该法离实际应用还有一段距离,因为烟气中含有一定量的氧气（大约3%⁵%）,而氧气存在造成催化剂失活。如何获得高选择性的催化剂就显得极为重要。为寻找含氧气氛下有效的催化剂,首先必须清楚它与各反应组分间相互作用情况。所以,本文以CO、SO₂和O₂为吸附质,利用程序升温脱附（TPD）技术对Fe、Co、Ni三种元素的氧化物、硫化物以及钙钛矿表面上的吸附作用进行了研究,分析了活性组分存在状态对催化剂表面脱附能量的影响,并且与催化剂活性进行关联。研究发现以下几点:Ni处于不同状态时对CO的吸附能力影响最为明显。当Ni状态从氧化物转变为硫化物时,与CO的作用能力朝弱方向偏移;当其为钙钛矿结构时,与CO作用最弱;Co和Fe的存在状态对CO的吸附能力影响相对较小。Co的存在状态对SO₂的作用能力影响较大。当Co以氧化物的形式存在时,其与SO₂作用能力最强,当以钙钛矿结构形式存在时,其与SO₂作用能力下降,当处于硫化物状态时,与SO₂作用更弱。在Fe和Ni中的情况也是如此。Fe的状态发生变化后,它对O₂的吸附能力也随之变化。当Fe状态从氧化物变为钙钛矿结构时,与O₂的作用能力减弱,当其为硫化物时与O₂作用更弱;Co和Fe的存在状态对O₂的吸附能力影响相对较小。当CO和SO₂在催化剂表面的脱附温度分别处于460℃⁸00℃和447℃⁸00℃时,催化剂具有活性,且上述两种反应组分起始脱附温度越低,催化剂活性就越高。在氧气存在的情况下,O₂与CoS催化剂的强吸附作用,可能是造成催化剂活性降低的原因。更多还原

【Abstract】 With the development of modern industry, a large mount of SO₂ inducing the more and more serious acid rain is emitted by all kinds of pollution sources. All governments and enterprises are paying great attention to the treatment of these harmful gases. The method using CO catalytic reduction of SO₂ has many advantages over others. However, there is still some distance from the practical application. The gas contains a certain amount of oxygen, which caused the deactivation of the catalysts. How to obtain highly selective catalysts becomes extremely important.In this paper, We take CO、SO₂ and O₂ as adsorption qualities, and take the advantage of the TPD technique to study the adsorption energy on different catalysts such as Oxides, sulphides and perovskite. Comparing the curve of activity with desorption energy, some results are attained as follows:States of Ni affects the CO adsorption capacity greatly. When changing Ni oxide into sulfide, the adsorption strength of CO becomes weaker. The adsorption strength is the weakest for perovskite. The adsorption strength is infirmly affected by States of Fe and Co.When Co is in the form of oxides, adsorption intensity of sulfur dioxide is the strongest. When in the form of the perovskite structure, adsorption intensity is in the decline. Adsorption intensity is the lowest in a state of sulfide. Fe and Ni are similar to Co.States of Fe influence the O₂ adsorption capacity greatly. When Fe oxide transferred into sulfide, the adsorption strength of O₂ becomes lower. The adsorption strength is the lowest for perovskite. The adsorption strength is affected by States of Fe and Co seriously.When the energy state of CO is from 460℃to 800℃and that of SO₂ from 447℃to 800℃, the catalyst can reduce SO₂ with CO. The closer energy of two components, the higher activity catalyst has. CO oxidation activity mainly depends on surface adsorption oxygen of catalyst.更多还原