FROM: David Randall, RTI International TO: Brenda Shine, EPA/OAQPS/SPPD FOR: Docket ID No. EPA-HQ-OAR-2010-0682 DATE: April 26, 2012 SUBJECT: Evaluation of the Stringency of Potentia l Standards for Gasoline Loading Racks at Petroleum Refineries
1. Purpose The purpose of this memorandum is to assess the relative stringency of two potential standards for gasoline loading racks at refineries: 1) the cu rrent requirements as specified in 40 CFR part 63, subpart CC and 2) a requirement to use subm erged loading and reduce transfer operations emissions by at least 95 percent. 2. Background Section 112(f) of the Clean Air Act Amendmen ts (CAA) directs the U.S. Environmental Protection Agency (EPA) to assess source catego ries regulated under section 112(d) of the CAA and determine whether any human health or e nvironmental risks remain from the continued emissions of hazardous air pollutants (HAP) fo llowing implementation of maximum achievable control technology (MACT) standards. The CAA fu rther states that if the MACT standards do not reduce lifetime excess cancer ri sk to the most exposed indivi dual to less than one in one million, the EPA must set additional standards to protect human health and the environment. Additionally, the EPA is required to review these technology-based standards and to revise them “as necessary (taking into account developm ents in practices, pr ocesses and control technologies)” no less frequently than every 8 years, under CAA section 112(d)(6). The Refinery MACT 1 (40 CFR part 63, subpart CC) was prom ulgated over 8 years ago and is now being reviewed. One aspect of the technology re view involves evaluation of cont rol practices and technologies for gasoline loading racks. Refinery MACT 1 currently requires Group 1 gasoline loading racks to meet the requirements in the National Emissi on Standards for Gasoline Distribution Facilities (Bulk Gasoline Terminals and Pipeline Breakout Stations) in 40 CFR part 63, subpart R. Group 1 gasoline loading racks are loading racks that have a maximum calculated design throughput greater than about 20,000 gallons per day (gal/d) of gasoline; a nd gasoline is defined as any petroleum distillate having a Reid vapor pressure (RVP) greater than 4 pounds per square inch absolute (psia) that is used as a fuel for inte rnal combustion engines. Th e standard specified in 40 CFR part 63, subpart R is an emission limit of 10 milligrams of total organic compounds per liter of gasoline loaded (mg/liter). All tank trucks and railcars that are loaded with gasoline mustTechnical Memorandum – Evaluation of the Stringency of Potential Standards for Gasoline Loading Racks at Petroleum Refineries April 26, 2012

2 undergo annual vapor tightness testing in accordance with Method 27 of 40 CFR part 60, appendix A-8. The maximum allowabl e pressure change is 25 millimeters of water in 5 minutes for tank trucks and railcars larger than 2,500 gall ons (greater pressure changes are allowed for smaller tank trucks and railcars). The EPA recently conducted a survey of control t echnologies for transfer operations (Randall, et al., 2012). One of the more cost-effective contro l options identified by this analysis would require, a facility that transfers more than 35 million gallons per year (gal/yr) (equal to about 100,000 gal/d) of liquids with a weighted averag e maximum true vapor pr essure (MTVP) equal to or greater than 4 psia use submerged load ing and to vent displaced emissions from the transport vehicles through a closed vent system to an air pollution control device (APCD) that reduces organic regulated materi al emissions by at least 95 pe rcent. Other techniques that achieve equivalent or better co ntrol would also be allowed as an alternative to the 95 percent reduction option. These alternativ es include vapor balancing to the storage vessel that is supplying the transferred liquid or routing displaced emissi ons to a fuel gas system. 3. Analysis of Transfer Operations Standards This analysis compares the control efficiency required under the current Refinery MACT 1 requirements to the 95 percent emission reduction option for transfers of several grades of gasoline at a model transfer rack. Model characteristics. The model transfer rack has one loading arm and transfers 10 million gal/yr of gasoline. The temperat ure of the gasoline was assumed to be 65 degrees Fahrenheit (°F), which is a rough approximation of the averag e annual temperature acro ss the southern half of the United States. Seven grades of gasoline we re evaluated. The RVP, true vapor pressure at 65 °F, and vapor molecular weight for each grade of gasoline from section 7 of the AP-42 are presented in Table 1 (EPA, 1995).

Table 1. Characteristics of Different Grades of Gasoline Parameters Characteristics for different grades of gasoline a RVP, psia 4 7 7.8 8.3 10 11.5 13.5 True vapor pressure at 65 °F 2.1 3.5 3.963 4.2188 5.2 6.069 7.2573 Vapor molecular weight, lb/lb-mol b 68 68 68 68 66 65 62

a The true vapor pressure and vapor molecular weight for gasoline with RVP between 7 psia and 13.5 psia were taken from Table 7.1-2 in AP-42. For gasoline with a RVP of 4 psia, the true vapor pressure was calculated using Equation 7.1-14b in AP-42, and the vapor molecular weight was assumed to be the same as for gasoline with a RVP of 7 psia. b lb/lb-mol = pounds per pound-mole.Technical Memorandum – Evaluation of the Stringency of Potential Standards for Gasoline Loading Racks at Petroleum Refineries April 26, 2012

3 Uncontrolled emissions. Uncontrolled emissions fr om transfers to tank trucks and railcars were estimated using the following equation from AP -42 section 5.2.2.1.1 with the saturation factor for splash loading (EPA, 1995): 

##       

#     

#   ) R ( R mol

- lb / psia ft 73

. 10 lb ton/2,000 gal 17

. 264 / ft 3145

. 35 gal mol

- lb/lb psia
3 3

 
   T Q M P S E

where: E = Volatile organic compound (VOC) emissions, pounds per year (lb/yr). S = Saturation factor (1.45 for splash loading; 0.6 for s ubmerged loading). P = True vapor pressure of transferred liquid, psia. M = Molecular weight of vapors, lb/lb-mol. Q = Quantity of liquid transferred, gal/yr. T = Temperature of transferre d liquid, degrees Rankine (°R).
Controlled emissions under current Refinery MACT 1 requirements. Regardless of the grade of gasoline or the type of contro l implemented, the controlled emissions must be no more than 10 mg/liter. Controlled emissions under 95 percent emission reduction option. Displaced emissions from tank trucks and railcars loaded by submerged load ing were estimated using the same equation presented above, with the satura tion factor for submerged loadi ng. Final emissions out of the control device were assumed to be equal to 5 percent of the inlet emissions. Results. Table 2 presents the uncontrolled emissions , controlled emissions (both total tons per year and mg/liter of gasoline tran sferred), and the percent reducti on for the model transfer racks under both standards. The analysis shows that th e 10 mg/liter standard in Refinery MACT 1 is more stringent than the alternative to require submerged loading and a 95 percent reduction of emissions for all grades of gasoline. The outle t emissions range from 12 to 42 mg/liter under the alternative control option rather than 10 mg/liter as required in Refinery MACT 1. In addition, the overall control efficiency is always 97.9 perc ent under the alternative control option, whereas the control efficiency ranges from 98.3 per cent to 99.5 percent under the current Refinery MACT 1 requirements. The current requirements in Refinery MACT 1 also are the MACT floor for petroleum refineries. Therefor e, Refinery MACT 1 cannot be re vised to be use the alternative control option of submerged fill and 95 percent c ontrol because the alternative control option is less stringent than the existing MACT floor control requirement.Technical Memorandum – Evaluation of the Stringency of Potential Standards for Gasoline Loading Racks at Petroleum Refineries April 26, 2012

4 Table 2. Emissions and Control Efficiency to Meet Gasoline Loading Standards in Refinery MACT 1 and the 95 Percent Reduction Option

Parameter Emissions and control efficiencies for model transfer racks RVP, psia 4 7 7.8 8.3 10 11.5 13.5 Uncontrolled emissions, tons per year (tpy) 24.3 45.6 51.1 54.7 64.7 74.8 85.2 Control option 1: Submerged loading and venting to APCD as required in Uniform Standards

Vented emissions from submerged loading, tpy 10.1 18.9 21.1 22.6 26.8 31 35.2 Controlled emissions out of APCD, tpy 0.504 0.944 1.06 1.13 1.34 1.55 1.76 Controlled emissions out of APCD, mg/liter 12.1 22.6 25.3 27.1 32.1 37.1 42.2 Overall control efficiency, percent 97.9 97.9 97.9 97.9 97.9 97.9 97.9 Control Option 2: Outlet emissions level as specified in Refinery MACT 1

Overall control efficiency, percent 98.3 99.1 99.2 99.2 99.4 99.4 99.5

4. References EPA (U.S. Environmental Protection Agency). 1995. Compilation of Air Pollutant Emission Factors, Volume 1: Stationary Point and Area Sources , AP-42, Fifth Edition, U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards. January 1995. Randall, D., C. Richardson Fry, and K. Sc haffner. 2012. Memorandum from David Randall, Carrie Richardson Fry, and Karen Schaffner, RTI International, to Nick Parsons, EPA/OAQPS, for Project Docket File (EPA Docket No. EPA-HQ-OAR-2010-0871). Survey of Control Technology for Transfer Operati on and Analysis of Impacts for Transfer Operation Control Options . January 20, 2012. Docket Item No. EPA-HQ-OAR-2010-0871- 0021.