(554g) CO2/N2 Separation Using Cu-BTC, Uio-66 and MIL-53(Al) Metal Organic Frameworks

CO₂/N₂
Separation Using Cu-BTC, UIO-66 and MIL-53(Al) Metal Organic Frameworks

Satyannarayana Edubilli, Pradip Das, Sasidhar Gumma

Department
of Chemical Engineering, Indian Institute of Technology Guwahati

Guwahati
- 781039, Assam, India.

Email:  s.edubilli@iitg.ernet.in (S.Edubilli), pradip.das@iitg.ernet.in (Pradip.das), s.gumma@iitg.ernet.in
(S. Gumma)

In
recent years Metal Organic Frameworks (MOFs) have gained
much attention for adsorptive separations due to their exceptional capacities,
tunable pore Structures and ease of regenarability. MOF materials are being extensively
studied in terms of equilibrium measurements, but for the practical application
point of view, they have to be tested for their cyclic and thermal stabilities
under process conditions.

In this presentation, the
results of breakthrough and cyclic adsorption experiments for CO₂ /
N₂ separation on different MOFs viz. Cu-BTC, Uio-66 and a flexible
metal organic framework MIL-53(Al) will be reported. MOF powders are made into beads
using PVA/H₂O as binder. Different ratios of MOF to binder were
prepared and the binder content was optimized based on its strength and surface
area. The adsorbent column was filled with MOF beads and this column was used
for breakthrough as well as the cyclic PSA adsorption experiments. A mixture of
15% CO₂ in N₂ was used as the feed. During the
experiments, the column pressure history, feed inlet flow rate, and column
outlet flow rate are recorded using data acquisition system. The column outlet
stream composition was analyzed using a Gas Chromatograph. The performance of a three step PSA cycle consisting of
pressurization, feed and blowdown as well as cycles incorporating N₂
purge and CO₂ rinse steps will be reported. In a typical experiment
about 10-12 grams of the adsorbent was used and the feed flow rate was about
200 cc/min. The adsorption step was carried out at about 1.3 bar, while
desorption was done at 0.1 bar.

In addition to these results
we also report, the effect of framework flexibility on the process performance.
In our earlier work on MI-53(Al) we have reported that the pores of parent MIL-53(Al) into narrow pore (np)
domain at ambient temperature in absence of guest molecules by manipulating its
history [1]. Using this procedure, we have studied the performance of MIL-53
(Al) using both lp and np
phased samples. Under the same experimental conditions, the observed CO₂
breakthrough times of lp and np phase materials are 180 and 510 seconds
respectively.

References

 [1] P. Mishra, S. Edubilli, H. Uppara,
B. Mandal and S. Gumma, Langmuir, 29, 12162-12167,2013