(478b) Role of Bed Design Characteristics on the Effective Thermal Conductivity of a Structured Adsorbent

The role of different design variables on the effective radial thermal conductivity of a structured adsorbent bed for potential applications in pressure swing adsorption (PSA) and temperature swing adsorption (TSA) processes is discussed. The structured adsorbent corresponds to a metal support consisting of layers of intercalated smooth and corrugated metal foils coated with 13X zeolite resulting in parallel triangular channels. The radial direction is perpendicular to the planes of the foils. The variables investigated include the thickness of the adsorbent coating, thickness of the metal, nature of contacts between smooth and corrugated foils, type of metal, presence and magnitude of an air gap between the foils, difference in alignment of the metal foil, difference in the coating methodology and effect of different void gases. The results show that the effective thermal conductivity is significantly improved if the foils are in direct contact either via imbedding or simply by point contacts. In such a situation, the thermal conductivity depends strongly on the conductivity of the metal and weakly on the conductivity of gas medium and all other design properties. In contrast, when the foils are separated either by air gaps or by sorbent coating, the effective thermal conductivity is not that different from that of a pelletized bed and depends strongly on the conductivity of the gas medium and weakly on the conductivity of the metal and all other design properties.