Experimental and numerical study on pyrolysis performance of waste salt in moving bed reactor

The efficient removal of organic impurities is critical for the reuse of industrial waste chlorine salt. The present paper proposes a moving bed reactor for the pyrolysis of organic impurities in waste salt. A three-dimensional multiphysics model was developed by coupling the pyrolysis reaction model and the heat and mass transfer model. The results of the study indicate that the pyrolysis process commenced at 574.92 K, with a pyrolysis reaction order of 2, an activation energy of 121.16 kJ/mol, and a pre-exponential factor of 3.59 × 10⁶ s⁻¹. On this basis, the effects of reactor outer diameter (D_out), initial temperature (T₀) and heating temperature (T_h) on the pyrolysis process were investigated. The effect of D_out on the pyrolysis energy consumption per unit mass (Q_m) is negligible. Conversely, an increase in T₀ can effectively reduce Q_m. The increase of T_h was effective in accelerating the pyrolysis, but the Q_m increased 64.34 % as T_h increased from 673.15 K to 973.15 K. Concurrently, the best moving rate (u_b) and Q_m were precisely predicted by establishing a multi-parameter regression model. This work provides critical design parameters for waste salt moving bed pyrolysis systems.