Unravelling stability mechanisms in petroleum coke–sludge slurry: A component‐decoupled study on the rheological and structural effects of oily sludge

Abstract The growth of the petroleum and chemical industries has increased the production of petroleum coke (PC) and oily sludge (OS), creating environmental challenges. Co‐slurry gasification of PC and OS offers a clean solution for resource utilization and harmless treatment. However, the stability mechanisms of petroleum coke‐sludge slurry (PCSS) remain poorly understood, which is key to optimizing slurry preparation and gasification. In this study, oil, solid, and water were separated from OS, and their effects on slurry rheology were analyzed. The results show that adding OS from 1 wt.% to 20 wt.% causes the apparent viscosity to first decrease and then increase by 208 mPa · s, with the lowest viscosity and best stability at 10 wt.% OS in PC. The oil phase improves flowability by lubricating and dispersing particles but increases thixotropic behaviour. The solid phase stabilizes the slurry by forming a skeletal structure and preventing sedimentation, though it increases viscosity due to internal friction. Porous sludge particles create a stabilizing network between PC particles. This study provides theoretical support for the industrial application of OS and PC co‐slurry gasification.