PDF Publication Title:
Text from PDF Page: 072
692 Fig. 7 Pressure drop measurements on the NaX beads and the structured adsorbent Adsorption (2008) 14: 687–693 though the volume of the packed bed and the monolith is the same. By increasing the film thickness 67 times to 100 μm to reach the same adsorption capacity for the structured adsor- bent as for the beads, the channel width would reduce from 1100 to 900 μm. Since the pressure drop is inversely propor- tional to the channel width to the power of four (Patton et al. 2004), the pressure drop should only increase about 2.2 times for a structured adsorbent with a 100 μm film. Thus, a structured adsorbent with the same adsorption capacity as traditional beads will still have 45 times lower pressure drop than beads. These results suggests that structured adsorbents have a great potential compared to traditionally used beads and that there is considerable scope to increase the film thickness and/or monolith cell density to increase the zeolite loading while still maintaining a lower pressure drop than that of a packed bed. In addition, shorter cycle times can be employed for the structured samples with thin films. However, in order to verify that the structured adsorbents are better than the beads in a PSA process, a complete math- ematical model and/or PSA experiments are needed, but this is beyond the scope of the present paper and will be pre- sented in future work. 4 Conclusions Dense, uniform structured adsorbents with limited amount of sediments were grown in 5 steps on porous ceramic cordierite supports. The CO2 adsorption capacity and the pressure drop of the NaX film grown with the multiple- step synthesis on the porous support were compared with the ones of NaX beads. Due to the low zeolite loading, the adsorption capacity per unit volume adsorption column of the thin NaX films grown in 5 steps was about 67 times lower than the NaX beads. However, the pressure drop in the column loaded with the structured adsorbent was 100 times lower than for the NaX packed bed, thus representing an ad- vantage for PSA applications. By increasing the film thick- ness 67 times it may be possible to equal the adsorption ca- pacity of the beads, while the pressure drop of a PSA column loaded with the structured adsorbents still would be 45 times lower than when the column is loaded with beads. These re- sults suggest the potential of structured adsorbents as com- petitive alternative to traditionally used packed beds in PSA processes. The adsorption capacity of the structured adsor- bents may be increased by growing thicker NaX films on the cordierite monoliths or by using substrates with a higher cell density. In addition, heat—and mass—transport phenomena in the films should be investigated and PSA cycles evaluated to explore the possibilities of these novel adsorbents. Nomenclature q: adsorbate loading on adsorbent, kg/kg k: geometricfactorinmasstransfercoefficientexpression in LDF equation, m−2 De: effective diffusivity, m2/s q∗: adsorbate loading in equilibrium with fluid phase, kg/kg l: zeolite film thickness, m R: radius of a zeolite bead, m Acknowledgements Qingdao JIT Corporation (Qingdao, China) is kindly acknowledged for providing the 13X molecular sieve zeolite beads. References Brandani, F., et al.: Adsorption kinetics and dynamic behaviour of a carbon monolith. Adsorption 10, 99–109 (2004) Chou, C.T., Chen, C.Y.: Carbon dioxide recovery by vacuum swing adsorption. Sep. Purif. Technol. 39, 51–65 (2004) Chue, K.T., et al.: Comparison of activated carbon and zeolite 13X for CO2 recovery from flue gas by pressure swing adsorption. Ind. Eng. Chem. Res. 34, 591–598 (1995) Cybulski, A., Moulijn, J.A.: In: Cybulski, A., Moulijn, J.A. (eds.) Structured Catalysts and Reactors. Dekker, New York (1998). Chap. 2 Glueckauf, E., Coates, J.I.: Theory of chromatography. Part IV: the in- fluence of incomplete equilibrium on the front boundary of chro- matograms and on the effectiveness of separation. J. Chem. Soc. 1315–1321 (1947)PDF Image | Structured Zeolite Adsorbents for PSA Applications
PDF Search Title:
Structured Zeolite Adsorbents for PSA ApplicationsOriginal File Name Searched:
structured-zeolites.pdfDIY PDF Search: Google It | Yahoo | Bing
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
Heat Pumps CO2 ORC Heat Pump System Platform More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)