Experiments were carried out in a conventional circulating fluidised bed to measure the axial pressure profile and total pressure drop, which covered a wide range of operating conditions. Materials belonging to the Geldart A (fine material) as well as the Geldart B (coarse material) categories have been used in the present work. Slip velocity is determined from the total pressure drop and noticed that the slip velocity is much higher than the free fall velocity of single particle for Geldart A type material, while it is approximately equal to the free fall velocity of single particle for the Geldart B type materials. A model is developed for slip velocity taking into account all the hindrance effects: particle-particle, particle-wall, and particle agglomeration. Predictions of the present model are validated with the data due to present study and the data reported in the literature.