MDI Emissions Reporting Guidelines for the ... - Polyurethanes

MDI Emissions Reporting Guidelines for the Polyurethanes Industry
here uses the actual formulas recommended by the EPA except that saturated vapor
concentrations are used instead of screening values. Since the vapor concentration of MDI
cannot exceed the saturation vapor pressure at a given temperature, the predicted
screening values are limiting and conservative values. The calculation methodology involves
the following steps:
1. Determine the saturated concentration of MDI.
2. Calculate emission factor for each equipment type.
3. Determine emissions for each equipment type.
4. Determine total losses from equipment leaks.
The MDI emissions from equipment leaks using the Modified Correlation Approach can be
determined using the following equations:
Where:
SV = 1,315.8 x 10
[(10.902 – 4634.09)/(266.15 + t)]
SV = Screening Value in ppmv and
t = Temperature in oC The calculated Screening Value (SV) is then inserted into the Leak Rate/Screening Value
Correlation Formula for the appropriate equipment type (found in Table D-1) and the
leakage rate is determined.
Table D-1
Leak Rate/Screening Value Correlations
Equipment Type Correlation Leak Rate (kg/hr) (a*(SV) b )
Gas Valve 1.87x10 -06 x (SV) 0.873
Light Liquid Valve 6.41x10 -06 x (SV) 0.787
Light Liquid Pump Seal c 1.90x10 -05 x (SV) 0.824
Connectors 3.05x10 -06 x (SV) 0.885
c This equation can be used for liquid pumps, compressor seals, pressure relief valves, agitator seals and heavy liquid pumps
The total emissions from equipment leaks will be equal to the emissions contributed from
each gas valves, light liquid valves, light liquid pumps, and connectors.
The emissions factors can be estimated from the following expressions:
For gas valves:
For liquid valves:
K gas = 1.87 x 10 -6 *(C mdi ) 0.873
K liq = 6.41 x 10 -6 * (C mdi ) 0.787
D-3