Study On The Equipment Technology For The Preparation Of Fuel Cell Catalyst Slurry

In this thesis, the combination of the high-shear and ultrasonic dispersion technique was raised to solve the problems which exists in the preparation of the Fuel Cell catalyst slurryThe basic dispersion mechanisms of the Fuel Cell catalyst slurry and the stator-rotor high-shear mixer were analyzed. Then, PIV technique was employed to visualize the velocity field of the stator-rotor high-shear mixer and based on the results and large eddy PIV theory, the kinetic energy dissipation rate was estimated. The CFD software-FLUENT was used to simulate the flow in the stirred tank. The velocity filed obtained agrees well with the PIV results. Further, the critical flow area that cannot be observed by PIV was analyzed. Finally, according to the experiment and simulation results, a specialized mixing equipment for Fuel Cell catalyst slurry was designed and the dispersion performance of the equipment was tested. TEM and laser particle size analyzer were used to characterize the slurry.It was found that the knock-on effect between the jet and the stator plays the most significant role in the nano-particle dispersion, followed by the high-shear effect and cavitation effect. The mechanism of ultrasonic dispersion is cavitation effect, which make the slurry fludization. The average particle size of the slurry prepared by the combination of high-shear and ultrasonic technique is smaller and the surface area bigger. The equipment has passed the actual productive tests and fully satisfied the technical requirements.