Cenosphere Formation and Combustion Characteristics of Single Droplets of Vacuum Residual Oils

The ignition, combustion characteristics, and cenosphere formation of single droplets four vacuum residues (VRs) from different refineries with various asphaltene contents were studied experimentally. VRs suspended at the tip a silicon carbide fiber heated in air temperatures 973 1023 K, respectively, an electrically tube furnace. ignition behavior recorded using CCD camera, which enabled determination droplet size, delay time, flame duration, size. effect initial gas temperature, content on morphology, particle size investigated. whole process consisted five stages succession: (1) pre-ignition, mainly involving evaporation highly volatile components surface; (2) steady fuel vapors evaporated (3) splashing interior; (4) disruptive due to thermal decomposition asphaltene; (5) solid residue combustion. A visible sooty was formed upon lasted during 2–4. increased sharply stage 4 asphaltene, more profound for higher temperatures. time increasing temperature but varied little as increased, suggesting that controlled by vaporization high surface. produced residue, form shell thickness being ca. 20 μm number blowholes presented shell. had bigger blowholes. ratio is independent almost linearly VRs.