Research on pyrolysis fluidization characteristics of oil shale

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Aiming at the inapplicability of classical fluidization theory to oil shale pyrolysis system featuring non-spherical, wide-size-distribution (0–3000 μm) and non-normally distributed shale powder and shale ash, as well as the lack of theoretical support for reactor scale-up and precise process control, this study systematically explores fluidization characteristics of shale powder and shale ash in fluidized beds and risers. Experiments were carried out on a coupled platform of Φ300 mm, Φ400 mm fluidized beds and Φ100 mm riser with air as fluidizing medium. Key parameters were measured via pressure drop method, differential pressure method and particle size analysis. Results show that the minimum fluidization velocities of shale powder and shale ash are 0.043 m/s and 0.040 m/s, with a uniform critical entrainment velocity of 0.7 m/s, defining the stable operating window of 0.043–0.7 m/s. Bed pressure drop presents a three-stage variation. Shale ash exhibits superior fluidization uniformity and stability. In risers, axial density shows a bottom-dense and upper-dilute distribution. This study clarifies the fluidization regulation mechanism of wide-size-distribution non-spherical oil shale-based particles, revises classical fluidization theory, and provides key theoretical and data support for reactor optimization and industrial scale-up.