Question 10.2: Outline the step-by-step procedures for design of a fixed-be...
Outline the step-by-step procedures for design of a fixed-bed regenerative carbon adsorption system for control of an emission stream containing a hazardous air pollutant.
Step 1
Use Eq. (3) to calculate the amount of carbon required (C_{req}):
C_{req} = (M_{HAP} θ_{ad} [1 + (ND/NA)])/W_{c} (3)
C_{req} = ــــــــــــــــــــــــــــــــــــــ lb carbon
The carbon required per vessel (C'_{req}) is determined by dividing carbon required (C_{req}) by the number of beds adsorbing (NA).
C'_{req} = C_{req}/NA
Step 2
If the HAP inlet loading (M_{HAP}) is not given, use Eq. (4) to calculate it.
M_{HAP} = 6.0 \times 10^{−5} (HAP_{e})(Q_{e})(D_{HAP}) (4)
M_{HAP} = ــــــــــــــــــــــــــــــــــــــ lb/hr
where
D_{HAP} = PM/RT (9)
D_{HAP} = ــــــــــــــــــــــــــــــــــــــ lb/ft³
Step 3
The vessel diameter, D_{v}, vessel length, L_{v}, and the vessel size, S, are obtained using Eq. (5), (7), and (8), respectively.
D_{v} = 0.127 C'_{req} U_{e}/Q'_{e,a} (5)
where
Q_{e,a} = Q_{e} (T_{e} + 460)/537 (7)
Q_{e,a} = ــــــــــــــــــــــــــــــــــــــ acfm
The emission stream flow rate per adsorbing bed (Q'_{e,a}) is obtained by dividing the HAP emission stream by the number of beds adsorbing (NA)
Q'_{e,a} = Q_{e,a}/NA
Q'_{e,a} = ــــــــــــــــــــــــــــــــــــــ acfm/bed
D_{v} = ــــــــــــــــــــــــــــــــــــــ ft
L_{v} = 7.87 (Q´_{e,a}/U_{e} )^{2}/C_{req} (6)
L_{v} = ــــــــــــــــــــــــــــــــــــــ ft
S = π D_{v} (L_{v} + D_{v}/2) (8)
S = ــــــــــــــــــــــــــــــــــــــ ft²