Study On Structure And Catalytic Properties Over Antioxidant Catalysts For Reductive Desulphurization

Sulfur dioxide (SO₂) is serious pollutant in our country, so it is important signality that the research of flue gas desulfurization (FGD) and reusing SO₂. In many FGD technologies, directly reducing sulfur dioxide in exhaust gases to elemental over a catalyst is attractive, however, the present of oxygen is a great problem. Therefore, researching and developing novel catalyst for reduction of SO₂ with CO in the presence of oxygen for FGD of coal-fired power plants is significant.Firstly, the paper studied emphatically the catalytic performance in the presence of oxygen with simulation of sulfurized LaCoO₃ catalyst, and investigated the affect of content about the catalytic activity and structure with sulfurized LaCoO₃ catalyst. Secondly, Substitution of strontium and iron in LaCoO₃ was also researched with XPS, XRD and TPD instruments. Lastly, We studied the reductive reaction of SO₂ by CO in the presence of oxygen with sulfurized LaBO3 (B= Fe.Co.Ni)catalysts ,and explored the relation of structural changes and catalytic activity.From the research results we can find there is a closed relationship between CoO content and the stability and lifetime of the catalysts, which is the sulfurized LaCoO₃-system in the presence of oxygen. Its stability and lifetime is increasing, and then rducing. its stability and lifetime of the catalysts are the longest when the content of CoO is 30% in mixed catalyst, and CO content is closed to the activity of sulfurized LaCoO₃ catalystl. XRD result shows its increasing is propitious to the existence of CoO. in addition, S species relates with the catalyst performance. S2- species has the great influence. The substitution of strontium or iron improves S-species content, and reduced SO42- species content. The study on the lifetime of sulfurized La0.7Sr0.3Co0.8Fe0.2O3 showed the relative content of S2- species and Fe3O4 were the key factor about the catalytic activity and lifetime. It had the stronger capability of resisting oxygen poisoning, and maximum O2 content was 7%. Space velocity was obvious on the lower temperature area(300℃～400℃),not on the higer temperature area(450℃～600℃). The structure of sulfurized LaBO3 decided the activity of the catalysts, which sulfides were main factors.