A composite catalyst containing H-Y zeolite and kaolin suitable for catalytic cracking of palm oil for the production of biofuels was synthesized by sol-gel-sieve method. In this study, we report the results of the hydrodynamic studies using a composite catalyst in a transport riser reactor. The hydrodynamic study confirms that the pressure difference across the transport riser reactor varies with the superficial gas velocity and it becomes significant at the bend section of the reactor. The pressure buildup occurs when the superficial fluid velocity reaches bubbling fluidization velocity. A model incorporating different dimensionless groups correlated with the pressure difference in transport riser reactor at different operating conditions. The proposed model predicted the pressure drop within an average error of +/- 20% in a transport riser reactor. (C) 2009 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.