【作者】 冉晓利；

【导师】 李春义；

【作者基本信息】 中国石油大学 ， 化学工程与技术， 2010， 硕士

【摘要】 在FCC再生器中,催化剂通过烧焦来进行再生。催化剂在烧焦的过程中,会生成SO2。SO2会对FCC装置造成腐蚀;排放到空气中,会形成酸雨等。由于催化裂化原料的含硫量增大和环境保护法规日益严格,迫切要求控制FCC烟气中SO2的排放。添加硫转移剂是有效降低烟气中SO2排放的最佳方案。如果硫转移剂在高效脱硫的同时,还能有效助燃,这不仅能提高人们使用硫转移剂的积极性,而且还能节约成本。本论文制备了一种新型的硫转移剂;并对其改性,使其同时具有脱硫和助燃的活性。首先,本文通过对活性组分、载体和制备条件的考察,制备了脱硫活性和稳定性很高的新型硫转移剂。实验结果表明,铈的作用主要体现在氧化吸硫方面,铁的作用主要体现在还原脱硫方面,氧化镁的含量有一个最佳值;制备的硫转移剂是含铈铁的富镁尖晶石,在实验室自制的脱硫装置上其脱硫活性为100%,具有很好的氧化吸硫-还原脱硫循环稳定性和很高的抗水热老化的能力。然后,把硫转移剂的脱硫实验进行放大。提升管小试表明,该硫转移剂的添加量占催化剂藏量的2%时,其脱硫活性为88%,且该硫转移剂对提升管的产物分布无明显的负面影响。大港工业试验结果表明,在硫转移剂的添加量为FCC催化剂藏量的2%时,烟气中90%的SO2被脱除,这比专利文献中普遍报导的脱硫率高,同时对FCC的产品分布和汽油的质量没有明显的不利影响。最后,通过添加氧化铜对硫转移剂的活性组分进行改性,使其同时具有硫转移和CO助燃的功能。实验结果表明:该双功能助剂是在硫转移剂上引入了1%的氧化铜。从XRD和BET的表征结果可以看出,引入1%的氧化铜在结构上对硫转移剂的影响很小;但其助燃活性明显得到了改善。在自制的实验装置上,在温度为200℃时,该助剂能把CO完全氧化为CO2;而且在脱硫实验装置上,在700℃时,其脱硫活性为100%,饱和吸附硫容略微增大。更多还原

【Abstract】 In fluid catalytic cracking(FCC) process, the burn-off of coke deposited on catalysts in FCC regenerator produces SOX(90%SO2 and 10%SO3). SO2 is one of the most hazardous atmospheric pollutants. SO2 and SO3 are acid rain precursors. And SO2 erodes FCC unit. Due to heavier feedstock and more and more stringent environmental regulations, it becomes urgent to cut down the emissions of SO2. In order to meet the requirement of environmental protection policies, sulfur-transfer additives are used in FCC process. If sulfur-transfer additives can highly effectively remove SO2, still can have good CO combustion activity, it will not only arouse people’s initiative but also save the cost. New sulfur-transfer additives were designed in my thesis, and the additives were modified to remove SO2 and CO.First, sulfur-transfer additives were prepared by systematic studies on active components, MgAl2O4 and preparation conditions in the self-made desulfurization unit in the laboratory. The experimental results demonstrated that the role of ceria was mainly reflected in SO2 oxidation. The role of iron was mainly reflected in SO2 reduction. The content of MgO in additives had an optimum value. The sulfur-transfer additives were ceria and iron-containing magnesia-excess spinels. The additives could completely remove SO2 from mixed reaction gas in the self-made desulfurization unit. The additives had very good SO2 oxidation–reduction performance and high hydrothermal stability.Then, sulfur-transfer additives were evaluated in riser pilot unit and FCC unit of Dagang Petrochemical Company. The riser test proved when appending 2% sulfur-transfer additives, SO2 in the flue gas was reduced by 88%. Moreover, it had no unfavorable effect on distributions of riser products. Industrial trial in Dagang’FCC unit showed when appending 2% sulfur transfer additives, sulfur-transfer additives’desulfuring activity was 90%. And it had no significant effect on distributions of FCC products and qualities of FCC gasoline. Finally, Cu as a combustion promoter was added into the sulfur-transfer additives, and the modified additives were tested in self-made fixed bed system. The experimental results showed that the weight content of CuO in the modified additives was 1%. The influence of CuO (1%) to sulfur-transfer additives was very small in additives’composition and structure. But additives’CO complete combustion temperature was reduced obviously, and additives’CO combustion activity was noticeably improved. Additives’combustion activity was 100% at 200℃and additives’SO2 saturation capacity increased. In a word, modified additives could simultaneously remove SO2 and CO.更多还原