MDI Emissions Reporting Guidelines for the ... - Polyurethanes

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MDI Emissions Reporting Guidelines for the Polyurethanes Industry Engineering Calculations Core Box Step: During this step, the MDI formulation is injected into the mold at ambient temperature. The losses will correspond to the total volume of air displaced from the molds at the filling temperature. A reasonable worst-case estimate of filling losses can be made based on the total volume of MDI formulation consumed, the composition of the MDI formulation and the injection temperature. The core box losses can be estimated from the following expression: Where: Therefore: L cb = V air * (1 / 359) * (273.15 / T cb ) * (VP mdi / 760) * MW * K mdi * C iso /100 Lcb = the emissions from the core box step in lb/yr Vair = the annual volume of displaced air in ft3 /yr (at the filling temperature) Tcb = he filling temperature in K VPmdi = the vapor pressure of MDI in mm Hg at the filling temperature MW = the molecular weight of MDI (250.26) Kmdi = an adjustment factor to the vapor pressure that is a function of MDI Ciso = concentration in the feedstock and the temperature the % of isocyanate feedstock in the total formulation. If only MDI/PMDI material is filled then Ciso = 100% L cb = V air * (1 / 359) * (273.15 / T cb ) * (VP mdi / 760) * MW * K mdi * C iso /100 Vair = 400,000 lbs Part 1 + 325,000 lbs Part 2= 725,000 lbs x 1 gal/10 lbs x 1 ft3 /7.45 gal Vair = 9692 ft3 /yr Tcb = the filling temperature in K = 20 o C + 273.15 o K = 293.15 o K VPmdi = the vapor pressure of MDI in mm Hg @20 o C = 5.28 x 10 –6 mm Hg MW = the molecular weight of MDI (250.26) Kmdi = an adjustment factor to the vapor pressure that is a function of MDI concentration in the feedstock and the temperature. 100 pure MDI is used in the feedstock K =1.0 Ciso = the % of isocyanate in the total formulation. 325,000 lbs x 39% / 725,000lbs Ciso = 0.04 L cb = (9692 ft 3 /yr)*(1/359)*(273.15/293.15)*(5.28 x10 -6 /760)*(250.26)*(1)*(.04) L cb = 1.80 x 10 -6 lbs/yr 5-33
MDI Emissions Reporting Guidelines for the Polyurethanes Industry Mold Pour and Shakeout Step During the mold pour and shakeout step, exhaust air blowers are used to maintain a slight negative pressure in the process area by continuously drawing air and exhausting it to the atmosphere through a series of exhaust stacks. Residual MDI is thus removed from the mold and the sand. For this situation the MDI emissions can be estimated by considering the air exhaust rate, the temperature of the exit gas, the residual free MDI in the mold, and the "effective" MDI concentration in the gas stream. As a worst-case scenario, it can be assumed that the air leaving the process area will be in thermodynamic equilibrium with the free MDI remaining in the mold. The losses from the mold pour and shakeout step can be estimated from the following expression: Where: L so = (V air /359) * (60) * (ppmv/1000000) * (MW) * (K mdi ) * (C iso /100) * (t so ) * (F mdi ) Lso = the emissions in lb/year from the shakeout and mold pour step Vair = the exhaust airflow rate in ft3 /min (at stack temperature) ppmv = the saturated concentration of pure MDI in air (in ppmv) at the stack temperature (Tst ). It is directly determined from the vapor pressure MW = the molecular weight of MDI (250.26) Kmdi = adjustment factor to the vapor pressure that is a function of the MDI/PMDI ratio in the isocyanates feedstock and the temperature, the value of Kmdi is 1.00 for pure MDI Ciso = the % of isocyanate feedstock in the total formulation Fmdi = the fraction of free MDI remaining in the mold. The free MDI is assumed to be 0.01 (1% of the initial MDI remains unreacted during this step) Tso = the total time of operation in hours/year 359 = the molar volume of an ideal gas in ft3 /lb-mole @ 0 o C and 1-atmosphere 60 = time, minutes/hour Mold Pour: Lmp = the emissions in lb/year from the mold pour step Vair = the exhaust airflow rate in ft3 /min (at stack temperature) ppmv = the saturated concentration of pure MDI in air (in ppmv) at the stack temperature (Tst ). It is directly determined from the vapor pressure MW = the molecular weight of MDI (250.26) Kmdi = adjustment factor to the vapor pressure that is a function of the MDI/PMDI ratio in the isocyanate feedstock and the temperature. The value of Kmdi is 1.00 for pure MDI 5-34
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MDI Emissions ISSUE AX173 • JULY
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MDI Emissions Reporting Guidelines
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Use of TRI Database MDI Emissions R
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Identifying Release Sources MDI Emi
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MDI Emissions Reporting Guidelines for the ... - Polyurethanes

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