Synthesis and optimization of a new starch-based adsorbent for dehumidification of air in a pressure-swing dryer
- Purdue Univ., West Lafayette, IN (United States)
Corn grits selectivity adsorb water from many types of organic vapors and are used commercially to dry 2.8 billion L of fuel-grade fermentation ethanol annually. Evaluation of grits in a pressure-swing dryer at 308 kPa, combined with analyses of their physical properties, showed that the specific surface of the grits (0.5 m{sup 2}/g) limited steady-state drying of air to a dewpoint of {minus}20 C. By selectivity taking advantage of the best features of the natural material, a new class of natural adsorbents with a higher affinity for water was then synthesized using materials derived from corn: starch and cob flour. The chemical composition of the synthesized adsorbent was determined, as well as specific physical properties. Scanning electron microscopy showed the synthesized adsorbent surface had a large number of macropores (10--25 {mu}m in diameter) unlike corn grits which have limited porosity. This material gave reasonable and reproducible results similar to those obtained with molecular sieves using a commercially available pressure-swing air dryer. After 70 h of operation at 30 psi, the new adsorbent provided air at a dewpoint of {minus}63 C. The methods for preparing this material and an explanation of its performance in terms of macroscopic and microscopic structural characteristics are described.
- OSTI ID:
- 238036
- Journal Information:
- Industrial and Engineering Chemistry Research, Vol. 35, Issue 4; Other Information: PBD: Apr 1996
- Country of Publication:
- United States
- Language:
- English
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