We develop a passivity based controller for a reaction diffusion system. The model used in the simulation study describes the vapor recovery reactor used in carbothermic aluminum reduction. It takes into account, non-catalytic gas-solid reactions, the moving bed of solid particles and the shrinkage of the unreacted particle core. The reaction diffusion system is solved using the finite element method. We use passivity based control to adjust the carbon feed and the heat input to achieve the required conversion and maintain the temperature along the reactor. The efficiency of the reactor is determined by calculating the extent of vapor recovery and the conversion of carbon particles. The sensitivity of different parameters such as solid flow rate and column height based on the reactor performance is also determined. We show that the control scheme based on the inventory balances performs well under various operating conditions. (C) 2010 Elsevier Ltd. All rights reserved.