Study On Structure And Properties Of Al₂O₃ Fiber Ceramic Catalyst Carrier

Aiming at the increasing the effluent standard of automobile exhaust and demand of cleaning catalyst carriers in the field of haze treatment.This paper comes up with a thought that one-dimensional Al₂O₃ micron fibers,Al₂O₃ nanofibers,Al₂O₃ nanofibers,SiC whisker and two-dimensional nanosheet composite on multi dimension to prepara of honeycomb fiber ceramic catalyst carrier.The research work includes:the preparation of Al₂O₃ nanofibers by the electrostatic spinning,in-suit growth of nanosheet on the nanofibers and crystal whisker,and preparation,structure and performance of fibrous porous catalyst support ceramics.The Al₂O₃ nanofibers were prepared by electrospinning,in which the distribution regularities of fiber diameter that was influenced by precursor solution and process parameters were discussed.Besides,the heat treatment parameters of gaining the continuous and homogeneous Al₂O₃ nanofibers were obtained,and the properties of the fiber membrane were studied.The results showed that the 30%Al2O3/DMF dispersion can produce better performance Al₂O₃ nanofibers with diameter shrinkage of 22%.The TiO₂ nanosheets modified the Al₂O₃ micron fibers were prepared by hydrothermal synthesis technology.The effects of HF,the ratio of HF and HNO₃,fibers,solvent heat temperature and reaction time were discussed.In addition,the research that TiO₂ nanosheets situ growth on the substrate surface of Al₂O₃ nanofibers,Al₂O₃ nanofibers and SiC whisker was carried out.The results show that the TiO₂nanoparticles can grow in different substrates under optimized process parameters.The TiO2 nanosheets modified Al2O3 fiber ceramic catalyst carriers were prepared by using slurry forming-high temperature curing-hydrothermal synthesis technology.The researchs of combination of agent type,binder addition,heat treatment temperature and configuring the sizing method influenceed the microstructure,volume density,volume ratio surface area and macroscopic mechanical strength of the carrier were elaborated carefully.The results showed that the carrier was prepared in the process route-silica sol as the binder,V_{（Water:silica）}=2:3,heat treatment of 1300℃,dip-solvent method.The carrier has a relatively low volume density of 0.48 g/cm³,high specific surface area of 7.84m².g^-1(37.9×10³ cm².cm^-3)and compressive strength of 2.01MPa.The anti-thermal shock performance and the anti-airflow erosion performance of the carrier were studied.It shows that the carrier can still be stable when the temperature is 800℃.There is no mass loss of carrier in the 12h of normal temperature airflow.The initial loss rate was about 20.1%.The loss rate tends to be stable after 4h,and the mass no longer changes.Therefore,the fiber ceramic carrier has good thermal shock resistance and anti-airflow erosion performance.