(345c) 3D-Printed SAPO-34 Structured Adsorbent for CO2 Separation
AIChE Annual Meeting
2017
2017 Annual Meeting
Separations Division
CO2 Capture By Adsorption II: Adsorbents
Tuesday, October 31, 2017 - 1:10pm to 1:30pm
Other types of adsorbent formulation that allow eliminating the limitations mentioned above are thus of large interest. Monolithic adsorbents are superior to classical packed bed adsorbents in terms of pressure drop and mass transfer kinetics. The honeycomb structure, mostly known from catalytic exhaust treatment in the automotive industry, is a well-known example, but monolithic structures are also used in liquid chromatography and heterogeneous catalysis. Nevertheless, the production of monoliths is complicated; classical extrusion processes only offer a very limited flexibility in the geometric properties of the monolith while polymerization processes are not suited for the production of materials for high temperature applications.
Recently, 3D-printing methods have tremendously expanded the possibilities in material synthesis, with much more degrees of freedom. In the present work, a new method to develop monolithic structures is tested for its use in gas and liquid adsorptive separation. Layers of adsorbent fibers are printed on top of each other, where each layer can have a different orientation. Fiber thickness and interdistance can be varied easily. This allows to generate structured adsorbents with a very high porosity, interconnected channels and high adsorption capacity. SAPO-34 based monoliths were produced in different geometries by this 3D-printing method. The obtained materials were characterized via Hg and Ar porosimetry to determine micro-, meso- and macroporosity. Adsorption capacities for CO2, N2 and CH4 were obtained via pure component isotherms measurements to allow comparison with the adsorbents in their initial powder form. It was demonstrated that the method developed at VITO allows to obtain materials with very large adsorption capacity and very good accessibility. Subsequently, the monoliths were subjected to breakthrough separation experiments. The separation of CO2 from flue gas was studied. Promising separation properties were obtained, with large selectivities, large capacities and low pressure drop. Depending on the chemical composition of the adsorbents, fast regeneration could be obtained under isothermal and thermal swing conditions.