MDI Emissions Reporting Guidelines for the ... - Polyurethanes

Calculating Stack Emissions
MDI Emissions Reporting Guidelines for the Polyurethanes Industry
To calculate the emissions for this process, the worst-case scenario will be presented. The MDI/PMDI
emissions will be generated from two areas. Emissions are released as (1) component A and
Component B mixture is being dispensed into the cavity and (2) as it is passed through the oven to be
cured. Therefore, the total amount of MDI/PMDI emitted will equal the amount emitted while being
dispersed plus the amount released during curing.
The total amount of emissions emitted during dispensing operations will correspond to the total
volume of air displaced at the temperature of the process. A reasonable worst-case estimate of
emissions can be made based upon the volume of the mold cavity, the number of pieces produced
per year, and the maximum process temperature.
The enclosed process losses can be estimated from the following expression:
Where:
L c = V air * (1 / 359) * (273.15 / T proc ) * (VP MDI / 760) * M w * K MDI
Lc = emissions from the enclosed process in lb/yr
Vair = the annual volume of displaced air in ft3 /yr
Tproc = the temperature material is dispensed at in K
VPMDI = the vapor pressure of MDI in mm Hg. at dispensed 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: Determine Annual Volume Displaced (V air )
Vair = Nf * Mdisp * *
Vair = Annual Volume in ft 3 Nf =
/yr
Annual Number of Filters Processed
Mdisp = Amount of Material Dispensed/Filter
= Density of Material lbs/ft 3
Therefore:
Vair = (670 filters/hr)(8760 hr/yr)(0.26 lbs/filter)(1 gal/10lbs)1 ft3 /7.48gal)
Vair = 2.04 x 10 +4 ft3 /yr
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