# December 2009



# Emission Estimation Protocol

for Petroleum Refineries

Version 1.0

Submitted to:

Office of Air Quality Planning and Standards

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Submitted by:

RTI International

3040 Cornwallis Road

Research Triangle Park, NC 27709-2194

# Appendix A—Average Stream Compositions



# Appendix A

Average Stream Compositions

A-1

# Appendix A—Average Stream Compositions

A-2 [This page intentionally left blank.]Appendix A—Average Stream CompositionsTable A-1. Refinery Average Stream Hazardous Air Pollutant Compositions—Default ValuesCASNumberHAP ComponentGasolineAlkylateCrude OilReformateNaphthaAvg. Conc. (wt%)Wtd Avg. Conc.(wt%)LiquidVaporLiquidVaporLiquidVaporLiquidVaporLiquidVaporLiquidVaporLiquidVapor106-99-01,3-Butadiene0.00370.0037540-84-12,2,4-Trimethylpentane4.720.95335.49.40.2630.2470.7990.3558.512.292.270.67971-43-2Benzene1.610.6260.1180.0610.4460.8074.613.321.2441.061.611.171.15461.02892-52-4Biphenyl0.010000.0610.000020.0250000.020.0000040.03961.15E-051319-77-3Cresols0.7890.00065000.2180.00080.1410.00020.01910.000030.230.00030.29050.000607498-82-8Cumene0.8490.015650.0040.00010.1260.01080.9680.0330.910.03680.570.020.42580.01638100-41-4Ethylbenzene1.6050.06310.0110.00060.3460.06333.730.2721.3660.1181.410.11.0180.08803110-54-3Hexane7.1384.4283.222.632.467.113.94.487.5310.274.855.784.0456.5511634-04-4Methyl tertiary-butylether3.543.62000000000.710.720.66690.6819891-20-3Naphthalene0.4440.00060.0120.000020.2190.001250.7980.00180.3990.00110.370.0010.33220.001131108-95-2Phenol0.05510.0001000.3230.00310.02760.00010.0660.00030.090.00070.20660.001850100-42-5Styrene3.5280.088200000.09070.0042000.720.020.67370.01703108-88-3Toluene7.210.8420.5030.0770.8780.47714.543.145.051.2955.641.173.8620.88601330-20-7Xylene7.170.2350.02120.00091.420.21613.790.83675.490.3955.580.344.1250.2941Sum of listed HAP38.710.939.312.26.768.9444.012.622.913.530.311.619.110.2A-3

# Appendix A—Average Stream Compositions



# Property Calculations

If the weight composition of a commodity is available but other property data are not, estimates can be

made. For example, if the liquid component mixture and the weight fraction for gasoline are known, then

the vapor pressure of the liquid, the MW of vapor, an d the weight fraction of the vapor can be estimated.

The following steps and equations may be used for calculating these estimates:

1. From the weight fraction values in the gasoline (liquid), Equation A-1 should be used to estimate

the number of moles of component “i.”

i i

i 

# MW Wtfrac

n = (Eq. A-1)

2. From moles of component “i” (liquid), Equation A-2 should be used to estimate the mole fraction

of component “i” (liquid).

T i

i



# n n

x = (Eq. A-2)

3. Equation A-3 should be used to calculate the partial pressure of each component “i” in liquid.

i 

# xP)i(P × = (Eq. A-3)

where:

P(i) = Partial pressure of component “i” (psia)

P = Vapor pressure of pure component “i” at the liquid temperature (psia)

x i 

# = Liquid mole fraction

4. To estimate the total pressure of the liquid, Eq uation A-4 should be used to estimate the average

vapor pressure for the gasoline mixture by summ ing the partial pressure of each component “i”

(liquid).

(Eq. A-4) 

# ∑

= n

i totalVP 

# P P

1



# 5. From mole fraction of component “i” (liquid), E quation A-5 should be used to estimate the mole

fraction of component “i” in the vapor using Raoult’s law.

totalVP

i

i 

# P P

y = (Eq. A-5)

6. Equation A-6 should be used to estimate the MW of the gasoline vapor, MW VAP 

# , using the mole

fraction of vapor (yi) and the MW of the pure component “i”(MW i 

# ).

(Eq. A-6) 

# ∑ ×= n

i i Vap 

# MWy MW

1



# where:

MW VAP 

# = Molecular weight of the vapor (lb/mol)

MW i 

# = Molecular weight of component “i” (lb/mol)

A-4

# Appendix A—Average Stream Compositions

7. Equation A-7 should be used to estimate the g asoline vapor weight fractions using the gasoline

vapor mole fractions and the MW VAP



# .

Vap i i

vap 

# MW MWy Wtfrac ×

= (Eq. A-7)

A-5 Example A-1: Calculation of Vapor Pressure and Molecular Weight for Gasoline

Loading Example

Calculate the vapor pressure of gasoline and MW VAP 

# for submerged loading of gasoline into

dedicated-service gasoline transport tank trucks (each with a volume of 8,000 gallons) based

on the following information:

The refinery loads 100 tank trucks per year at a bulk temperature of 90°F. Property data are

available for liquid composition of the gasoline only and are provided in Table A-2

.

First, the vapor pressure for each constituent is determined at the loading temperature using

Antoine’s equation and Antoine’s coefficients, su ch as those provided in Table 7.1-5 of AP-42

(U.S. EPA, 1995a).

Using Steps 1 through 7 from this Appendix A

, the gasoline liquid mole fraction can be

calculated from the weight fraction or weight percent component composition, the partial

pressure of each component in liquid, and the gasoline vapor mole fraction using Raoult’s law

(see each calculation “step” in the columns in Table A-2 ).

 Step 1.

i i 

# Wtfrac

n i 

# MW =

 Step 2.

T i 

# x =

i



# n n

 Step 3. 

# xP *



# = i 

# iP

)(

 Step 4. 

# ∑

i 

# P

= n

totalVP 

# P

1



#  Step 5.

totalVP i



# = i 

# P P

y

 Step 6.

ii 

# MW MW 

# ∑

= n

Vap 

# y

1 

# *

 Step 7.

Vap ii 

# wtfrac

vap 

# MW MWy *



# =

See Table A-2 for the calculations of thee variables. At 90° F, the total system vapor pressure is 5.641

psia and the MW of the vapor, MW GasolineVAP 

# , is 65.984 lb/lb-mol.Appendix A—Average Stream CompositionsTable A-2. Sample Calculation of Average Molecular Weight and Vapor Weight FractionStep 1Step 2Step 3Step 4Step 5Step 6Step 7ABCD=C/AE=D/(ΣD)F=E*BG=F/(ΣF)H=G*AG=H/(ΣH)*100%CAS NumberCompoundMolWtPvap at 90°F(psia)GasolineLiquid (wt%)GasolineLiquid (moles/100 g)GasolineLiquid (molefraction)GasolinePartialPressure(psia)Gasoline Vapor(mole fraction)MolWtContributionGasoline Vapor(g/mol)GasolineVapor (wt%)106-99-01,3-butadiene54.0950.530.00376.840E-076.206E-053.136E-035.559E-043.007E-020.04561634-04-4Methyl tertiary butyl ether88.153.6663.544.016E-043.643E-021.336E-012.368E-022.087E+003.16110-54-3Hexane86.183.9707.1388.283E-047.514E-022.983E-015.288E-024.557E+006.91540-84-12,2,4-Trimethylpentane114.21.3364.724.132E-043.749E-025.008E-028.878E-031.014E+001.5471-43-2Benzene78.112.5441.612.061E-041.870E-024.758E-028.434E-036.588E-010.998108-88-3Toluene92.140.79117.217.825E-047.099E-025.615E-029.955E-039.172E-011.391330-20-7Xylene106.10.25427.176.755E-046.128E-021.558E-022.762E-032.931E-010.444100-41-4Ethylbenzene106.20.27581.6051.512E-041.371E-023.782E-036.704E-047.118E-020.108100-42-5Styrene104.20.19213.5283.387E-043.073E-025.904E-031.047E-031.090E-010.16598-82-8Cumene120.20.13690.8497.064E-056.408E-038.774E-041.555E-041.869E-020.028391-20-3Naphthalene128.20.0085550.4443.4642E-053.143E-032.689E-054.766E-066.109E-049.26E-0492-52-4Biphenyl154.20.0010590.016.485E-075.883E-056.231E-081.105E-081.703E-062.58E-06108-95-2Phenol94.110.012530.05515.855E-065.311E-046.656E-061.180E-061.110E-041.68E-041319-77-3Cresols108.10.0084220.7897.296E-056.619E-035.574E-059.881E-061.069E-030.0016274-98-6Propane44.1162.50.0012.268E-072.057E-053.342E-035.924E-042.613E-020.0396106-97-8n-Butane58.1243.794.78.087E-047.336E-023.213E+005.695E-013.310E+0150.275-28-5Isobutane58.1217.041.72.925E-042.654E-024.521E-018.015E-024.658E+007.06109-66-0n-Pentane72.1513.323.95.405E-044.904E-026.533E-011.158E-018.356E+0012.778-78-4Isopentane72.154.9207.91.095E-039.933E-024.888E-018.664E-026.251E+009.47Other VOC100.20.553143.134.304E-033.904E-012.159E-013.828E-023.836E+005.81nTPtotalVPMWvapTotals100.01.1021.0005.6411.00065.98100.0A-6