2 research outputs found
Adsorption and Desorption of Mixtures of Organic Vapors on Beaded Activated Carbon
In this study, adsorption and desorption of mixtures
of organic
compounds commonly emitted from automotive painting operations were
experimentally studied. A mixture of two alkanes and a mixture of
eight organic compounds were adsorbed onto beaded activated carbon
(BAC) and then thermally desorbed under nitrogen. Following both adsorption
and regeneration, samples of the BAC were chemically extracted. Gas
chromatography–mass spectrometry (GC-MS) was used to quantify
the compounds in the adsorption and desorption gas streams and in
the BAC extracts. In general, for both adsorbate mixtures, competitive
adsorption resulted in displacing low boiling point compounds by high
boiling point compounds during adsorption. In addition to boiling
point, adsorbate structure and functionality affected adsorption dynamics.
High boiling point compounds such as <i>n</i>-decane and
2,2-dimethylpropylbenzene were not completely desorbed after three
hours regeneration at 288 °C indicating that these two compounds
contributed to heel accumulation on the BAC. Additional compounds
not present in the mixtures were detected in the extract of regenerated
BAC possibly due to decomposition or other reactions during regeneration.
Closure analysis based on breakthrough curves, solvent extraction
of BAC and mass balance on the reactor provided consistent results
of the amount of adsorbates on the BAC after adsorption and/or regeneration
Two-Dimensional Modeling of Volatile Organic Compounds Adsorption onto Beaded Activated Carbon
A two-dimensional heterogeneous computational
fluid dynamics model
was developed and validated to study the mass, heat, and momentum
transport in a fixed-bed cylindrical adsorber during the adsorption
of volatile organic compounds (VOCs) from a gas stream onto a fixed
bed of beaded activated carbon (BAC). Experimental validation tests
revealed that the model predicted the breakthrough curves for the
studied VOCs (acetone, benzene, toluene, and 1,2,4-trimethylbenzene)
as well as the pressure drop and temperature during benzene adsorption
with a mean relative absolute error of 2.6, 11.8, and 0.8%, respectively.
Effects of varying adsorption process variables such as carrier gas
temperature, superficial velocity, VOC loading, particle size, and
channelling were investigated. The results obtained from this study
are encouraging because they show that the model was able to accurately
simulate the transport processes in an adsorber and can potentially
be used for enhancing absorber design and operation