MDI Emissions Reporting Guidelines for the ... - Polyurethanes

Process Description
MDI Emissions Reporting Guidelines for the Polyurethanes Industry
A two component system, (Component A: Polyol mixture; Component B: MDI/PMDI mixture),
is dispersed into the motor home roof cap forming a polyurethane foam insulation at a rate
of 42 pounds/hour. The temperature of the process is 78 o
F. The targeted foam density is
2.0 pounds/ft 3 .
Calculating Stack Emissions
To estimate emissions from open processes when the volume of the mold is not known or
when a large number of different cavity or mold sizes are filled each year can be
determined from the following:
1. The density of the cured foam.
2. The total weight of the MDI-based component in the foam.
3. The temperature of the foam at the tack-free time during the curing process.
The enclosed process losses can be estimated from the following expression:
Where:
L fd = V air * (1 / 359) * (273.15 / T proc ) * (VP MDI / 760) * M w * K MDI
Lfd = emissions lb/yr
Vair = annual volume of displaced air in ft3 /yr
Tproc = process temperature in K (maximum temperature of the MDI)
VPMDI = vapor pressure of MDI in mm Hg at process temperature
Mw = 250.26 (this is the molecular weight of MDI)
KMDI = adjustment factor to the vapor pressure that is a function of MDI
concentration in the feedstock and the temperature
359 = the molar volume of an ideal gas in ft3 /lb-mole @ 0 o
C and 1-atmosphere
Step I: Calculate Annual Volume of Displaced Air (V air )
Vair = (Amount of material processed/year)/Foam Density
Vair = (42 lbs/hr)(8760 hr./year)(1/2.0 lbs/ft3 )
V air = 1.84 x 10 +5 ft 3 /yr
Step II: Calculate Process Temperature in K
The process temperature is 78 o
F or;
T proc = 298.7 K
5-45