Multi-scale modeling and control of autothermal reactors for the production of hydrogen

The interest in economically efficient hydrogen production has been steadily increasing, and even more so recently, given the progress made in the development and implementation of fuel cell technologies. Autothermal reactors, combining exothermic and endothermic reactions are one of the most promising hydrogen production technologies. A discussion covers the dynamics of autothermal reactors; arguments from singular perturbation theory; existence of two distinct time scales in dynamic behavior; reduced-order, nonlinear models for the dynamics in each time scale; comparative dynamic simulation results using the rigorous model of two hydrogen production reactors; mechanisms by which changes in production rate or disturbances in the operating parameters can cause the reactors to transition from an ignited to an extinguished state; and challenges associated with the implementation of feedback control to alleviate the issues encountered in running autothermal reactors. This is an abstract of a paper presented at the 2006 AIChE Annual Meeting (San Francisco, CA 11/12-17/2006).