Sorption of toxic chemical vapors in fixed bed adsorbers containing activated carbon fiber cloth and modeling of diffusivity and mass transfer
- Univ. of Illinois, Urbana, IL (United States). Dept. of Civil Engineering
Under the 1990 Clean Air Act Amendment (CAAA), the United States Environmental Protection Agency (USEPA) is establishing maximum achievable control technology (MACT) standards to reduce industrial toxic emissions by 97 to 99%. These regulations have encouraged the development of new technologies to capture and recover toxic chemical vapors (TCVs) from gas streams. Development of such new air quality control devices requires the integration of experimental and modeled results to optimize capabilities of the new devices. In this research, a new activated carbon fiber cloth (ACFC) adsorber coupled with an electrothermal regenerator and a cryogenic condenser was designed and developed to efficiently capture and recover TCVs from gas streams. The system was characterized for adsorption by ACFC, electrothermal desorption, and cryogenic-condensation to separate acetone, methyl ethyl ketone (MEK), 1,1,1-trichloroethane (TCA), and toluene from simulated gas streams. Adsorption throughput ratios (TPRs) averaged from 76% to 50% for an effective length of 18 cm and packing density of 94 mg/g. Electrothermal desorption produced high concentration gas streams for reduced desorption times, low thermal losses, and low adsorbate retentivities. Electrothermal regeneration of a saturated ACFC with acetone produced a 63% by volume acetone effluent in 5.4 min with an energy consumption of 1 KJ/g-carbon/g-acetone, while heat loss to the carrier gas stream was not appreciable. Concentrating the vapor in a short time enabled to increase the operating temperature of condenser while achieving a high recovery efficiency > 97%. Modeling sorption dynamics is important to be able to predict the system characteristics during the scale-up and optimization. A systematic experimental and modeling approach is developed to reduce the number of required experiments to adequately characterize the system.
- OSTI ID:
- 679323
- Report Number(s):
- CONF-980632--
- Country of Publication:
- United States
- Language:
- English
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