## Technical Memorandum

TO: EPA Docket No. EPA-HQ-OAR-2010-0682

FROM: Brenda Shine, Environmental Engineer Refining and Chemicals Group, SPPD (E143-01)

DATE: January 6, 2014

SUBJECT: Post Control Modeling Results

I. Purpose:

The purpose of this memo is to summarize the approach used to estimate the risk reductions associated with the proposed control scenario s on the Petroleum Refini ng source category. While the draft risk report for the source category presents post control risk results relating to maximum individual risk (MIR), in cidence, and non cancer effects for all emission sources in the refining source categories, this memorandum pres ents additional result s related to cancer incidence and incidence reductions associated with specific types of emission sources.

II. Background:

The EPA conducted a detailed Information Coll ection Request (ICR) of all U.S petroleum refineries. The ICR had four components: (1) a questionnaire on processes and controls to be completed by all petroleum refineries (Compone nt 1); (2) an emissions inventory to be developed by all petroleum refine ries using the emissions estimati on protocol developed for this effort (Component 2); (3) distillation feed sampling and analysis to be conducted by all petroleum refineries (Component 3); and (4) em issions source testing to be completed in accordance with an EPA-approved protocol for speci fic sources at specific petroleum refineries (Component 4). The emissions inventory submitted in response to Component 2 of the ICR was used as the input for the modeli ng file to estimate the risk asso ciated with refinery process emissions.

III. Post Control Scenarios:

For each emission source within the refining MACT 1 or MACT 2 source categories, we applied a reduction in emission estimates resulting from application of proposed controls. The “postcontrol” emission file used th e quality-assured ICR Component 2 emissions file as a starting point. As facilities could report in Component 2 the groupings of sources included in Component 1, it was not practical to perform the post-contro l emission estimates at the individual release point level. Instead, facility-spe cific emission reduction factors we re developed from the results of the technology review analysis conducted us ing ICR Component 1. Th ese reduction factors were used to adjust the emissions of all pollutants reported for that specific source type at that facility to account for the post-control emi ssions. For example, an overall HAP emission reduction factor was calculated for storage tanks for a given f acility based on the number and types of tanks, the type of fluid in the tank a nd the additional controls required to comply with2 the proposed standards for storage vessels. That overall HAP reduction factor was then applied uniformly to all storage vessel emissions (all poll utants) reported for that facility. Table 1 presents emissions, before and after control, associated with the proposed controls, which impacts delayed coking units, equipm ent leaks, and storage vessels.

TABLE 1. EMISSION REDUCTIONS FROM POST CONTROL SCENARIO

Emission Process Group Baseline,
TPY Post Control,
TPY Reductions Boilers (external combustion) 381 381 0% Catalytic cracking unit vent 5081 5081 0% Catalytic reforming unit vents 92 92 0% Chemical processes HON 12 12 0% Chemical processes hydrogen 34 34 0% Coking unit vents & coke handling 410 218 47% Cooling towers 2078 2078 0% Degreasing/cleaning/painting 78 78 0%
Flares 1189 1189 0% Fugitive dust/blasting/construction 147 147 0%
Incinerators 78 78 0% Internal combustion engines 198 198 0%
Labs 3 3 0% Marine vessel loading and unloading 244 244 0% Miscellaneous process vents 57 57 0%
Other combustion 3 3 0% Other waste treatment/disposal 4 4 0% Process equipment leaks 2982 2982 0%
Process heaters 1467 1467 0% Refinery processes (other) 618 618 0% Storage vessels 1664 969 42% Sulfur recovery unit vents 482 482 0% Tank car & truck loading and unloading 68 68 0%

Wastewater treatment 2776 2776 0%
TOTAL 20145 19257 4%

It is important to note that the emission reducti ons anticipated from app lication of the proposed standards as presented in Table 1 differ from the rule’s presented impacts because of the way in which the baseline emission estimates were devel oped. In developing the impacts for the rule, emission estimates were developed using modeling techniques and site-sp ecific data on the units as reported in Component 1 of the ICR (e.g., size of vessels, temperature of coke drum when venting, number of valves and pumps, type of roof and fitting controls, etc.). The modeled3 baseline emissions estimates for storage vesse ls agree reasonably well with the industry’s reported emissions inventory beca use the emission estimation procedures for these sources has been well established for years. The modele d baseline emission estimate for delayed coking units were quite different from the reported emis sions for several reasons. First, the emission estimation protocol for delayed coking units is new and not all facilities reported emissions for their delayed coking units or they reported em ission but did not use the emission factors and methodologies provided in the Emission Estimation Protocol for Petroleum Refineries (RTI, 2011). As such, the emissions reported in the re finery-supplied inventory dataset (Component 2) were less than projected using the Protocol ’s default emission factor and the number of coke drums and cycle times as reported in Component 1 of the ICR. Second, in order to develop impacts for different control options, a more deta iled model had to be developed to account for changes in emissions at diffe rent coke drum vessel venting pressures (and/or drum temperatures). Consequently, there may also be a significant difference in the emissions estimated using the impact model’s unit-specific approach and the emissions estimated for that same unit using the Protocol ’s default emission factor.

Given the differences outlined above, a delayed coking unit projected to have large baseline emissions when developing the rule’s impacts is likely to average (or no) emissions in the reported inventory. The delayed coking units with the largest modeled ba seline emissions were those that reported to vent at the highest drum temperature or pressure, so these units were also the units that had the largest emission reductions when controls were applied. If these units did not have the high baseline emissions in the industry-supplied invent ory, the overa ll percent emission reduction calculated in the inventory dataset would be less than the emission reductions projected using the impact model dataset. For example, assume the impact model’s baseline emission estimates for delayed coking units at th ree facilities were 5, 10, and 100 tons/yr and the post-control emissions were 5, 10, and 10 tons/yr, resulting in a projec ted 78 percent reduction from baseline. From this data , post-control reduction factors fo r these facilities would be 0, 0, and 90 percent, respectively. If the emissions re ported in the inventory for these three facilities were 6, 8, and 7 tons/yr, the post-control invent ory would be calculated as 6, 8, and 0.7 tons/yr (applying the 90 percent reduction for Facility 3), resulting in only a 30 percent reduction in the post-control inventory emissions.

Emission estimating procedures for dela yed coking units presented in the Protocol were new and uncertain. These methodologies were further re vised when developing impacts for control options, leading to high emissions projected for a select number of facilities. Even with the differences in the emission estimation approach used between the impacts model and inventory data set, the post-control factors applied to the inventory dataset still project significant emissions reductions from delayed coking units.

IV. Post Control Incidence

The cancer incidence for key emission sources as determined using th e reported (baseline) emissions inventory data and th e post-control inventory emission estimates is presented in Table 2 and graphically presented in Figure 1.4 TABLE 2. INCIDENCE REDUC TION FROM CONTROLS

Emission Source Baseline Cancer Incidence (cases/yr) SourceContribution to Baseline Cancer Incidence (% of total) Postcontrol Cancer Incidence (cases/yr) Reduction in Cancer Incidence % Reduction in Cancer Incidence from Source % Reduction in Cancer Incidence

Overall Delayed Cokers 0.104 31% 0.052 0.052 50% 15% Equip Leaks 0.078 23% 0.078 0 0% 0%
Wastewater 0.042 12% 0.042 0 0% 0%
FCCU 0.033 10% 0.033 0 0% 0% Cooling Towers 0.021 6% 0.021 0 0% 0% Storage Tanks 0.025 7% 0.015 0.010 39% 3%
Flares 0.018 5% 0.018 0 0% 0%
Other 0.018 5% 0.018 0 0% 0%

Total 0.340 100% 0.278 0.062 18%

V. References

RTI. 2011. Emission Estimation Protocol for Petroleum Refineries. Version 2.1.1, Final ICR Version Corrected. Prepared for U.S. Envi ronmental Protection Agency, Office of Air Quality Planning and Standards, Research Triangle Park, NC. May 2011.5Figure 1. Comparison of cancer incidence pre-control (baseline) and post-control for key refinery emission source0.000.020.040.060.080.100.12

Cancer Incidence (Cases per year)RefinerySourceCancerIncidenceforEachSourcebyPollutant(Prevs.PostControl)OtherCadmiumCompoundsFormaldehydeEthylbenzeneNickelCompoundsFormaldehyde1,3‐ButadieneChromium(VI)CompoundsArsenicCompoundsBenzidineEthylenedibromideNaphthaleneBenzenePOM