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Gas Phase Activated Carbon Adsorption 411

4.9. Carbon Suppliers, Equipment Suppliers, and Service Providers
The activated carbon suppliers, carbon adsorption system manufacturers, carbon
desorption (regeneration) system manufacturers, regeneration service providers, and
disposal service providers can be found in the literature (26,27). The new test methods
for the activated carbon industry (28), training opportunities (29), and more GAC
information (30) can be found in the literature.
5. DESIGN EXAMPLES
Example 1

Toluene is known to be a HAP in a contaminated gaseous emission stream, at 1000 ppmv
90ºF stream temperature. The partial pressure of the HAP may be determined by using Eq.
(2) and the working capacity of activated carbon by using Eq. (1).

Solution
The following contaminated air emission stream was obtained from an industrial plant:
HAP = toluene
Stream temperature, T = 90ºF
e
HAP emission stream concentration, HAP = 1000 ppmv
e
Because the adsorption isotherms for toluene are presented in Table 1, the default value
for a working capacity of 0.100 is not needed in this example. Table 1 presents the
isotherms for toluene at an adsorption temperature of 77ºF, which is lower than the
stream temperature of 90ºF in this example. Assume that this difference in temperature
does not significantly affect the calculation results. The working capacity value, W , is
c
usually 50% of the equilibrium capacity (W ). Using Eq. (1) and values from Table 1,
e
the W is calculated as follows:
e
W = k (P ) m (1)
e partial
where
−6
P = (HAP ) (14.696 × 10 ) (2)
partial e
−6
−6
P = (HAP ) (14.696 × 10 ) = 1,000 ppmv (14.696 × 10 ) = 0.0147 psia
partial e
From Table 1, k = 0.551, and m = 0.110. Then, substituting into Eq. (1) yields
W = (0.551) (0.0147 psia) 0.110
e
W = 0.346 lb toluene/lb carbon
e
Because the working capacity, W , is usually 50% of equilibrium capacity (W ),
c e
W = 0.50 W = 0.50 (0.346 lb toluene / lb carbon) = 0.173 lb toluene/lb carbon
c e
Because the adsorption isotherm for toluene was available (Table 1), the default value for
working capacity of 0.100 is not needed in this example.

Example 2

Outline the step-by-step procedures for design of a fixed-bed regenerative carbon adsorp-
tion system for control of an emission stream containing a hazardous air pollutant.