Predictive modeling of molten slag flow behavior along the axial and circumferential directions in the coal gasifier wall

Under the “dual carbon” goal, the coal gasification technology will be a critical development pathway for China's coal industry in the future. In the practical application and promotion of coal gasification technology, slag flow behavior significantly impacts the operational stability and longevity of gasifiers, and indirectly affects the quality of syngas produced. Currently, predictive models for molten slag flow behavior in vertical gasifiers have been relatively well-established. However, predictive models for molten slag flow behavior at the wall surface of inclined gasifiers require further refinement. The characterization of temperature, viscosity, and velocity distribution of liquid slag necessitates additional investigation.This study proposes a novel predictive model for molten slag flow to analyze the axial and circumferential slag flow behavior along the wall of an inclined gasifier. The model is formulated based on the assumptions that the mass and heat outflow of liquid slag in both axial and circumferential directions are solely dependent on gravitational components and flow cross-sectional area, and that no slag dripping occurs during the flow process. Using the Prenflo gasifier as the research object, the proposed model is compared with existing slag prediction models under the condition of γ = 0, demonstrating superior predictive accuracy. By varying the gasifier inclination angle (0–75°), the model successfully predicts various characterizing parameters of stable slag flow within the gasifier at different angles, exhibiting broad applicability. Then, the model characterizes the complete slag growth, flow, and heat transfer processes through a transient numerical solution, and effectively simulates the dynamic response of slag flow parameters before and after perturbation in ash deposition rate.