Handbook of Solvents - George Wypych - ChemTech - Ventech!

18.2 Prediction of organic solvents emission 1229
Figure 18.2.1. Chromatogram of substances emitted during degreasing. Oven temperature 40 o C. 1 - benzene, 2 -
2,2-dichloromethylpropane, 3 - butyl ester of formic acid, 4 - methylbenzene, 5 - water, 6 - 1-butanol, 7, 8, 10, 11,
12, 13, 14 - derivatives of methyl ethyl benzene, 9 - propyl benzene.
where:
C concentration, mg/m 3
q sum of ventilation flow rates, m 3 /min
E emission, mg/min.
Thus,
E=C×q [18.2.2]
The value C can be measured, but a value for q is difficult to estimate, because it includes
mechanical and gravitational ventilation (central air conditioning, influence of open
doors, windows, fans and natural ventilation).
When the process of degreasing ends, the decay of concentration can be described by:
C t = C e × exp(-t × q/V) [18.2.3]
where:
Ce concentration of the emission at the termination of the process, mg/m 3 ,
t duration of process, min,
V room volume, m 3 .
After a transformation:
q = (lnC e -lnC t)×V/t [18.2.4]
The quantity emitted to a room of known volume depends only on the changes of concentration
at time (t).