Premium
Pressure swing adsorption: Effects of incomplete purge
Author(s) -
Matz Michael J.,
Knaebel Kent S.
Publication year - 1988
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.690340910
Subject(s) - purge , pressure swing adsorption , adsorption , chemistry , cabin pressurization , oxygen , chromatography , analytical chemistry (journal) , nitrogen , vacuum swing adsorption , thermodynamics , waste management , materials science , organic chemistry , composite material , physics , engineering
Theoretical and experimental studies of pressure swing adsorption (PSA) cycles for various extents of purging have been conducted. In both the theoretical and experimental portions, pressurization was accomplished with product rather than with feed. A simple, local equilibrium model was employed, and the results were analyzed by the method of characteristics. It was found that for difficult separations (i.e., closely spaced isotherms and/or heavily contaminated feeds), incomplete purging, e.g., as little as 50% complete, yielded recoveries attainable only at much higher pressure ratios with complete purge. Conversely, for easy separations (i.e., widely spaced isotherms and dilutely contaminated feeds), incomplete purging was less attractive, yielding only slight improvement over complete purge. Splitting oxygen from air with zeolite 5A is moderately difficult due to the proximity of the isotherms and due to the predominance of the more strongly adsorbed nitrogen in the feed. This case was also modeled and was studied experimentally. The experiments yielded nearly double the recovery of oxygen for minimal purge compared with that available with complete purge. The productivity of oxygen was relatively high, e.g., 0.0378 m 3 (O 2 at STP)/kg (adsorbent) · h. Those experiments validated the trends predicted theoretically.