Preliminary Study of Using Spent Fluid Catalytic Cracking (FCC) Catalyst in Asphalt Binders

摘要

The amount of spent fluid catalytic cracking (FCC) catalyst is nearly 80 kt~90 kt annually in China, which damages the environment seriously and causes great waste of resources. How to deal with the spent catalyst is an emergency to be solved. This research explored the possibility of using this material in the asphalt binder. Two kinds of spent catalysts from different sources were selected. First, the properties of the two spent catalysts were characterized in terms of the particle size distribution, crystalline phase, chemical compositions, BET specific surface area, and surface microstructure. Then, the influences of the catalysts on the conventional properties, viscosity, storage stability, as well as the short term aging of asphalt binder containing the spent catalyst, were studied. And the blending mechanism was also investigated using Fourier transform infrared (FTIR) spectroscopy. It was found that the average diameter of catalyst A is 28.5 μm and for B the average diameter is 64.9 μm X-ray diffractiometer (XRD) results indicated that the spent catalysts contain AI_2O_3, SiO_2, and Y zeolite. X-ray fluorescence (XRF) data presented that the two spent catalysts are mainly made up of AI_2O_3 and SiO_2. Also, the specific surface areas for the two catalysts are more than 100 m~2.g-l. The scanning electron microscope images showed that A and B are spherical granules, and there are pores on the surface. Regarding the asphalt properties, it was found that the penetration and the ductility were dropped, while the softening point and the viscosity were improved with the increase of the spent catalyst dosage. And the asphalt binders containing catalyst with smaller size showed better performance due to the good dispersion in the asphalt binder as proposed. Asphalts with spent catalyst A presented good storage stability at all condition periods. However, asphalts with catalyst B did not show this property once its loading level is 8% and the conditioning time is 12 h or longer. The spent catalyst A and B illustrated the similar influences on the short aging properties of asphalt binder. FTIR spectrum indicated that this blending process was a physical mixing, and there is no chemical reaction occurred between asphalt and spent catalysts.