Thermal Desorption Process Simulation and Effect Prediction of Oil-Based Cuttings

The disposal effect of thermal desorption of oil-based cuttings is predicted by analyzing the material temperature rise, heat transfer, and liquid evaporation in the processing. Based on the characteristics of material conveying in the heating bed, this paper establishes the governing equations for the simulation calculation of thermal desorption processing and demonstrates the correlation model between the mass change of wet components and the heat required. Changes in the material temperature and mass content of wet components in the process are calculated using the finite-volume method. The minimum temperature of the material layer experienced three stages: slow rising stage, stagnation stage, and rapid rising stage. In the first two stages, material preheating and water evaporation are the dominant processes. The third stage is mainly the evaporation of the oil phase. The inflection point between the second and third stages in the temperature rise curve can be regarded as the end point of water evaporation. During conveying, residence time and material layer thickness significantly influence the liquid phases removal ratio. The material drying area gradually expands from the boundary to the center with the extension of residence time, and the average mass fraction of liquids decreases slowly. The evaluation results from the final temperature and residual oil content of solid slag after disposal are consistent with the tests and have better accuracy in predicting the disposal effect when the heating temperature is higher and the residence time is longer.