Adjoint Formulation and Sensitivity Analysis for Flows through Porous Media with Adsorption.*

Adsorbed Natural Gas (ANG) technology has gained importance, lately, in storage applications due to the development of more effective adsorbent materials. However, its widespread use still poses a few challenges. Among them, the exothermic character of the adsorption process is no small matter. For a temperature rise will hinder the adhesion of gas molecules to the adsorbent bed, thus diminishing its storage capacity altogether. Under these circumstances, the thermal management of adsorption is an attractive proposal. While for small tanks that may be accomplished by passive devices, larger ANG reservoirs may require active thermal management systems, comprising heat exchangers and more sophisticated control of the transient filling process. In order to address those questions, with especial emphasis on active systems, we derive a continuous form of the adjoint problem to porous media flows with adsorption. Our approach allows for the computation of sensitivities with respect to both device geometry and operational conditions. This work focuses on the later case, presenting sensitivity calculations which enables future optimizations cases.