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314 Lawrence K. Wang et al.

Table 2
Design Equations for Condensing Systems

H = HAP [∆H + C (T – T )]
con con p HAP e con
H = HAP C (T – T )
uncon o,m p HAP e con
H = [(Q /392) – HAP ] C (T – T )
noncon e e,m p air e con
HAP = HAP – HAP
con e,m o,m
−6
HAP = (Q /392)[1 − (HAP x 10 )][P /(P – P )]
o,m e e vapor e vapor
HAP = (Q /392)HAP × 10 -6
e,m e e
Note: C p HAP = average specific heat of compound (Btu/lb-mol ºF)
HAP = entering concentration of HAP (ppmv)
e
HAP = molar flow of HAP inlet (lb-mol/min)
e,m
HAP = molar flow of HAP outlet (lb-mol/min)
o,m
∆H = heat of evaporation (Btu/lb-mol)
P = system pressure (mm Hg)
e
P = P
vapor partial
Q = maximum flow rate (scfm at 77ºF and 1 atm)
e
T = condensing temperature (ºF)
con
T = entering emission stream temperature (ºF)
e
Source: US EPA (1991).
where C p HAP is the average specific heat of the HAP for the temperature interval T con −T e
(Btu/lb-mol ºF). (See the Appendix.)
2c. Calculate the enthalpy change associated with the noncondensible vapors (i.e., air) (basis:
1 min):

H noncon = Q ( [ e 392 ) − HAP e m] C p ( T − T ) (6)
con
e
,
air
where C p air is the average specific heat of air for the temperature interval T con −T (Btu/lb-
e
mol ºF). (See the Appendix.)
3a. Calculate the condenser heat load (Btu/h) by combining Eqs. (5) and (6):
H load = 11 × 60 H ( con + H noncon ) (7)
.
where H is the condenser heat load (Btu/h), H is the enthalpy of condensed HAP,
load con
and H is the enthalpy of the noncondensible vapors. The factor 1.1 is included as a
noncon
safety factor.
Table 2 summarizes design equations for condensing systems.
3.4. Condenser Size
Condenser systems are typically sized based on the total heat load and the overall
heat transfer coefficients of the gas stream and the coolant. An accurate estimate of
individual coefficients can be made using physical/chemical property data for the gas