posted on 2021-05-04, 14:34authored byJohn H. Jacobs, Connor E. Deering, Kevin L. Lesage, Mitchell J. Stashick, Robert A. Marriott
Evaluation of adsorbent
integrity over thousands of cycles is necessary
to establish the service time and sustainability of adsorbents employed
in industrial dehydration. Herein, an adsorption apparatus for rapidly
cycling multiple adsorbents through a thermal swing adsorption process
is introduced with results for 2000 cycles. This apparatus has eight
sample cells arranged in parallel, which are embedded in an aluminum
block for rapid heating and cooling. At the outlet of each cell, the
water content and temperatures are measured using capacitance relative
humidity sensors, which incorporate resistance thermometers. The analysis
of the breakthrough curves generated for each adsorbent gives inference
into the change in water uptake capacity over continuous cycling.
To handle the large sets of data generated by this instrument, an
automated analysis program was implemented. To demonstrate the functionality
of the instrument, zeolites 4A and 13X were cycled in a thermal swing
process over 2000 cycles and the change in the uptake capacity was
monitored by the analysis of the breakthrough plots for each cycle.
Furthermore, the results of the breakthrough analyses were verified
with the thermogravimetric analysis of the adsorbents. From these
experiments, zeolites 4A and 13X were observed to lose 7 ± 3
and 19 ± 7% of the adsorption capacity, respectively.