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Three‐bed PVSA process for high‐purity O 2 generation from ambient air
Author(s) -
Jee JeongGeun,
Lee SangJin,
Kim MinBae,
Lee ChangHa
Publication year - 2005
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.10548
Subject(s) - chemistry , pressure swing adsorption , air separation , vacuum swing adsorption , simulated moving bed , breakthrough curve , chromatography , zeolite , boiler blowdown , adsorption , analytical chemistry (journal) , diffusion , kinetic energy , separation process , thermal diffusivity , dehydration , single stage , thermodynamics , oxygen , catalysis , organic chemistry , engineering , inlet , aerospace engineering , mechanical engineering , biochemistry , physics , quantum mechanics
A three‐bed PVSA (pressure vacuum swing adsorption) process, combining equilibrium separation with kinetic separation, was developed to overcome the 94% O 2 purity restriction inherent to air separation in the adsorption process. To produce 97+% and/or 99+% purity O 2 directly from air, the PVSA process with two zeolite 10X beds and one CMS bed was executed at 33.44–45.60 to 253.31 kPa. In addition, the effluent gas from the CMS bed to be used for O 2 purification was backfilled to the zeolite 10X bed to improve its purity, recovery, and productivity in bulk separation of the air. PVSA I, which made use of a single blowdown/backfill step, produced an O 2 product with a purity of 95.4–97.4% and a recovery of 43.4–84.8%, whereas PVSA II, which used two consecutive blowdown/backfill steps, produced O 2 with a purity of 98.2–99.2% and a recovery of 47.2–63.6%. Because the primary impurity in the O 2 product was Ar, the amounts of N 2 contained in the product were in the range of 4000–5000 ppm at PVSA I and several tens of ppm at PVSA II. A nonisothermal dynamic model incorporating mass, energy, and momentum balances was applied to predict the process dynamics. Using the linear driving force (LDF) model with constant diffusivity for the equilibrium separation bed and a modified LDF model with concentration dependency of the diffusion rate for the kinetic separation bed, the dynamic model was able to accurately predict the results of the experiment. © 2005 American Institute of Chemical Engineers AIChE J, 2005