【作者】 王永成；

【导师】 马智；

【作者基本信息】 天津大学 ， 工业催化， 2005， 硕士

【摘要】 在现代工业的发展过程中,大量的工厂烟气排放到大气中,对环境造成了恶劣的影响,其中SO₂是最为严重的污染物之一,各国致力于环境保护的研究人员对SO₂的脱除工艺进行了大量的研究。通过对烟气中组成的分析,人们开发了许多有关CO的脱硫工艺,并系统的研究了相关催化剂的脱硫性能,CO催化还原脱硫就是其中的一种。但人们对含氧气氛下各气体组分之间的反应过程研究还有所欠缺。本课题将对含氧烟气中SO₂的自由基反应行为和催化脱硫过程进行研究,并考察丙酮加入及与热催化联合操作对反应过程的影响。实验采用波长254nm的低压汞灯作为激发光源,分别在SO₂+N₂、SO₂+O2+N₂、SO₂+CO+N₂、SO₂+O2+CO+N₂气氛下研究SO₂的自由基反应行为,计算反应过程中SO₂的转化率以及SO₂转化为SO3的量,并根据相关的文献,推测和验证自由基反应的路径,分析O2、CO等组分对自由基反应的影响程度。认为光照混合体系的反应过程中既有氧化路径,也有还原路径, O2的存在是SO₂氧化生成SO3的主要原因。在上述过程中引入丙酮后的实验结果显示,丙酮在上述光照下可光解为甲基和CH₃CO等自由基,其自由基主要与氧反应,而对其他组分的影响相对较小。混合烟气光催化反应和自由基反应协同作用效果的研究表明, TiO2催化剂的催化作用可同时作用于氧化过程和还原过程,其中SO₂和CO之间的还原反应较为明显;而ZnO和NiO催化剂的催化作用主要表现在SO₂和O2之间的反应方面。光化学反应和热催化还原反应联合作用结果表明,经光照后的混合气体组成发生了变化,在进入热催化反应之后,其中的某些组分促进了SO₂转化,提高了SO₂热催化反应的转化率。更多还原

【Abstract】 In the modern industry developing process, the massive factories exhaust gas hasbeen sended out to the atmosphere,which has made the bad influence to theenvironment.In the pollutant SO₂ is the most serious one, many researcher whodevoted to the environmental protection studied the removing technicses of SO₂ fromthe flue gas.On the basis of the components of the flue gas, the people have developedmany related desulphurization technicses about CO, and have researched the catalystperformance in desulphurization, for example,the reduction of SO₂ to S by CO. Butthe detailed free radical reaction process under the oxygen atmosphere between thevarious components has not been demonstrated. We study the reaction process of theSO₂ free radical, analyze and validate the reaction route, and analyze the affluence tothe process by joining the acetone and catalyst to the mixed gas.The experiment adopts the low-voltage mercury light of wavelength 254nm asthe light source , in SO₂+N₂, SO₂+O2+N₂ , SO₂+CO+N₂ and SO₂+CO+O2+N₂atmosphere separately.We study the reaction process about the free radical of SO₂,and calculate its conversion and the yield of SO3 under the atmosphere, and accordingto relevant documents , infer and validate the reaction route of the free radical ,analyze the influence of such component parts as O2 , CO ,etc. We consider that theoxidation and reduction route exist in the reaction.But,we know that the reaction isoxidation primarily,and the existence of O2 is the main reason of the increasing ofyield of SO3.Because of the negative function of O2 in reaction process , we assume to addsome kind of additive in the reaction to remove the oxygen influence. We add theacetone into the process and research the reaction between the CH3 free radicalproduced by acetone and SO₂ free radical ,O2,etc.The experimental result explain thatthe CH₃ free radical can remove O2 and has little influence to other components. Wereview the influence of the adding of catalyst to the free radical reaction byresearching the cooperation between catalytic reaction and free radical reaction.Weuse the sol-gel method to prepare the nano TiO₂ and use the precipition method toprepare nano ZnO and NiO,and find that TiO₂ affects the oxidation and the reductionprocess and mainly promotes the reaction between the SO₂ free radical and CO. But,ZnO and NiO catalyst can only promote the reaction between the SO₂ free radical andO2. Finally, we study the union process about irradiation and the hot catalyzedreaction and research the SO2 reaction process. The component of the mixed gaschangs after the irradiation reaction,and some component in the gas promote the SO2conversion in the hot catalyzed reaction.更多还原