Preparation and Anti-coking Effect of TIN, TiO2 Coatings in Microchannels

In order to inhibit the metal catalytic coking, a TiN coating was deposited on the inner surface of stainless steel oil duct with the internal diameter of 2 mm and the length of 700 mm by chemical vapor deposition (CVD), in the process of which the deposition temperature was set as 800 degrees C for 2 h. Furthermore, the TiN coating turned into TiO2 coating in oxidizing atmosphere at 700 degrees C. The coating's morphological features and textures were characterized by SEM, EDS and XRD. As shown in SEM, the surface of the TiN and TiO2 coating prepared by CVD, is continuous, close-packed and homogeneous. According to the observation of EDS, both of them are stoichiometric. The results from XRD indicate that the TiN in the coating has cub phase and the TiO2 has ruffle phase. A supercritical cracking system was set up for preliminary evaluating of the coking inhibition characteristic of two kinds of inhibitors and with some hydrocarbon fuel A as feedstock. The results show that compared with the 304 blank tube, the duration time of fuel cracking at high temperature is enhanced obviously in TiN and TiO2 coating tubes, and the anti-coking performance of TiN is more significant.