An evaluation of the physicochemical characteristics and reactivity in soot derived from heavy fuel oil gasification processes

During the entrained flow gasification (EFG) process, soot formation not only diminishes the efficiency of carbon conversion, but also poses challenges to the steady operation of the equipment. This study delves into the distinguishing characteristics between soot derived from residual oil gasification (RO) and that from slurry-bed hydrogenation oil residue gasification (OR), specifically examining their physical, chemical attributes, and reactivity. A comparative analysis is further extended to commercial carbon blacks, N330 and N990, to provide a comprehensive understanding. Thermogravimetry analysis (TGA) outcomes reveal a hierarchical order in the activation energy (Ea) for soot gasification in a CO2 environment, with RO exhibiting the highest followed by N990, N330, and OR respectively. These findings underscore variations in their intrinsic reactivity. Transmission electron microscopy (TEM) and Raman spectroscopic investigations highlight that the reactivity of soot in gasification is predominantly governed by factors such as carbon structure, content, and graphitization level, rather than being directly correlated with the specific surface area (SSA). The fractal dimension (DP) analysis, coupled with TEM imagery, suggests that RO shares similarities in physical attributes with N330, indicating a potential role as an alternative material in relevant applications. Additionally, OR is found to contain elevated levels of V, Mo, and Ni, suggesting opportunities for the recovery and recycling of these valuable metals, thereby contributing to resource sustainability. Overall, this research contributes to a deeper insight into the complex dynamics of soot formation in EFG processes and explores avenues for both process optimization and resource recovery.