FROM: Karen Schaffner and Jeff Coburn, RTI International

TO: Brenda Shine, EPA/OAQPS/SPPD

FOR: Docket ID No. EPA-HQ-OAR-2010-0682

DATE: November 22, 2013

SUBJECT: Review of HAP Emission Factors for Fl uid Catalytic Cracking Units based on Component 4 Source Test Data

1. Purpose
This memorandum compares the emissions factors derived from recent source test data of fluid catalytic cracking units (FCCU) to those provided in the Emission Estimation Protocol for Petroleum Refineries (RTI, 2011).
2. Background
On April 1, 2011, the U.S. Environmental Protection Agency (EPA) sent an information collection request (ICR) to faci lities in the petroleum refi ning industry (EPA, 2011). The ICR was comprehensive and designed to collect inform ation on processing charac teristics, crude slate characteristics, emissions inventories and source testing to bolster our current data and fill known data gaps. 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).
Component 4 of the ICR requested source testing for twelve different types of emission sources or units, one of which was the FCCU. For FC CU sources, source testing was requested for 10 different units, selected to cove r a variety of operating conditions ( e.g. , units using complete burn FCCU versus partial burn FCCU followed by a carbon monoxide (CO) boiler; units using electrostatic precipitators versus wet scrubbers for particulat e matter (PM) control). Owners or operators of the FCCU at the selected facilities were required to test for:

 Speciated volatile organic h azardous air pollutants (HAP)

 Speciated semi-volatile organic HAP

 Total hydrocarbons, methane, and ethane

 Aldehydes

 Carbon monoxide

 Dioxins, furans, and polychlorinated biphenylsTechnical Memorandum – Review of HAP Emissi on Factors for Fluid Catalytic Cracking Units November 22, 2013

2  Hydrogen chloride, chlorine, hydrog en fluoride, and hydrogen cyanide

 Mercury (speciated)

 Hexavalent chromium and multiple metals

 Particulate matter (PM, filterable PM with a diameter less than 2.5 micrometers (PM 2.5 filterable), and PM condensable) and ammonia

 Nitrogen oxides (NO X ), sulfur dioxide (SO 2 ), oxygen (O 2 ), carbon dioxide (CO 2 ), moisture, and gas flow rate
3. Developing Emission Factors from the FCCU Source Tests
For most source tests, the hourly mass emission rate of a pollutant was directly reported. For some tests, the pollutant concentration may ha ve been reported and the hourly mass emission rate was calculated based on the process vent fl ow rate. The hourly mass emission rates were divided by the hourly average proces s feed rate to calculate an em ission factor in units of pounds per million barrels of feed (lb/MMbbl). Thus, in order to develop emission factors from the source test results, one must have both the emissi ons data (emission rates) and process data. The pollutant concentrations and emission rates dete rmined during the source tests are considered emissions data and cannot be claimed as conf idential business information (CBI). However, process operating data, such as process feed rate s, may be claimed as CBI. For the purpose of this analysis, only non-CBI data we re used. If process rates we re reported and not claimed as CBI, then the process data reported was used. For facilities that claimed a ll their process data to be CBI, process feed rates were estimated base d on the process unit capacity as reported by the Energy Information Agency (EIA, 2011). The Emission Estimation Protocol for Petroleum Refineries (RTI, 2011), hereon simply referred to as the Protocol, also includes emission factors normalized by coke burn-off rates. However, c oke burn-off rates were generally claimed CBI and there was no easy way to estimate the coke bu rn-off rates (other than assigning a fixed coke burn-off rate per feed rate), so independent em ission factors based on coke burn-off rates could not be derived from the non-CBI data.
4. Comparison of F CCU Emission Factors
As part of the ICR, refineries were required to submit a complete emissions inventory file following the guidelines provided in the Emission Estimation Protocol for Petroleum Refineries (RTI, 2011). This Protocol included default emi ssion factors for a variety of HAP from FCCU. Owners or operators of FCCU that did not ha ve any test data or other “higher ranked” methodologies for estimating HAP emissions from th e FCCU were expected to use these default emission factors. In general, most FCCU owne rs or operators have not conducted HAP emission tests, so it is anticipated that most refineries used the default emission factors from the Protocol document to develop their FCCU emission estim ates. Table 1 summarizes the default HAP emission factors for FCCU from the Protocol and those derived from the Component 4 source tests. Note: Table 1 does not include metals. Metals were generally expected to be estimated based on the PM emission rate and HAP concentra tion of the FCCU dust. Default concentration ratios of certain HAP to nickel were provided in the Protocol; it was assumed all facilities would know nickel FCCU dust concentrations.Technical Memorandum – Review of HAP Emissi on Factors for Fluid Catalytic Cracking Units November 22, 2013

3 Table 1. Comparison of HAP Emissions Factors for FCCU Catalyst Regenerator Vent

CAS No. a Compound Emissions Factor from Protocol

Document (lb/MMbbl) b Preliminary Emissions Factor from Source Test Data (lb/MMbbl) b,c Volatile Organics 75-07-0 Acetaldehyde 20 54 67-64-1 Acetone 2.4 5,100 107-02-8 Acrolein 1.0 71-43-2 Benzene 18 38 74-83-9 Bromomethane 2.1 106-99-0 1,3-Butadiene 0.033 100-41-4 Ethylbenzene 0.24 50-00-0 Formaldehyde 260 52 75-09-2 Methylene chloride 6.7 490 108-95-2 Phenol 8.7 108-88-3 Toluene 3.5 370 75-69-4 Trichlorofluoromethane 2.4 1330-20-7 Xylene 3.2 Semi-volatile Organics 83-32-9 Acenaphthene 0.0033 0.0012 208-96-8 Acenaphthylene 0.13 0.0025 120-12-7 Anthracene 0.10 0.020 56-55-3 Benzo(a)anthracene 0.00052 0.029 50-32-8 Benzo(a)pyrene 0.011 0.0048 205-99-2 Benzo(b)fluoranthene 0.0035 0.0048 192-97-2 Benzo(e)pyrene 0.00045 0.0054 191-24-2 Benzo(g,h,i)perylene 0.0046 0.00026 207-08-9 Benzo(k)fluoranthene 0.0026 0.0026 218-01-9 Chrysene 0.0033 0.024 53-70-3 Dibenz(a,h)anthracene 0.0042 206-44-0 Fluoranthene 0.093 0.041 86-73-7 Fluorene 0.037 0.0069 193-39-5 Indeno(1,2,3-cd)pyrene 0.0044 0.0048 91-57-6 2-Methylnaphthalene 0.026 0.028 91-20-3 Naphthalene 1.0 0.52 85-01-8 Phenanthrene 0.24 0.078 129-00-0 Pyrene 0.0031 0.11 Dioxins/Furans 57117-31-4 Pentachlorodibenzofurans 5.5E-07 1.8E-06 57117-44-9 Hexachlorodibenzofuran 1.1E-06 8.8E-07 35822-46-9 Heptachlorodibenzo-p-dioxin 9.4E-07 4.3E-07Technical Memorandum – Review of HAP Emissi on Factors for Fluid Catalytic Cracking Units November 22, 2013

4 Table 1. Comparison of HAP Emissions Factors for FCCU Catalyst Regenerator Vent

CAS No. a Compound Emissions Factor from Protocol

Document (lb/MMbbl) b Preliminary Emissions Factor from Source Test Data (lb/MMbbl) b,c Inorganics 7664-41-7 Ammonia 13,000 690

75-15-0 Carbon disulfide 0.56 71 7647-01-0 Hydrogen chloride 1,800 120

74-90-8 Hydrogen cyanide 770 7,700 7439-97-6 Mercury 1.1 0.094

a CAS No. = Chemical Abstracts Service registry number.

b Emissions factors for FCCU controlled for organics in lb/MMbbl of CCU feed.

c Emissions factors from the Component 4 source test based on reported data. These data have not been fully reviewed in terms of quality assurance of results and me thod detection limits. As such, these emission factors are considered preliminary.

Generally, emission factor agreem ent within a factor of 2 is reasonable considering the HAP emission data set used when developing the emission factors for the Protocol document (generally tests conducted in the 1990’s). There are some differen ces that appear significant, and these are discussed briefly in the following paragraphs.

Considering the volatile organic HAP, the emission factors derived from Component 4 test data for acetone and methylene chloride are much greater than those provided in the Protocol. These pollutants are common laboratory contaminants and they are not expected to be released in significant concentrations. Initia l review of supporting documenta tion revealed that many of the tests had high acetone and methylene chloride con centrations in the blank. Consequently, we concluded that the preliminary Co mponent 4 test data emission fact ors were likely overstated. The toluene Component 4 emission f actor was also much higher than the Protocol default factor. There was only one Component 4 test that meas ured toluene above the method detection limit. This test is being further revi ewed to understand the source of th e high toluene emissions, but it is not appropriate to develop an emission factor based on one test.

The emissions factors developed for different semi -volatile organics varied widely, with some test data emission factors much higher than the Pr otocol default factors and others much lower. These compounds are also referred to as polycyc lic aromatic hydrocarbons (PAH) and they can be grouped by their cancer risk factor relative to benzo(a)pyrene. T hus, one can calculate a toxicity equivalent emission f actor for PAH considering all of the individual PAH emission factors. The total PAH emission factor, weight ed as benzo(a)pyrene, from the Protocol is 0.098 lb/MMbbl, and it is 0.050 lb/MMbbl from the te st data. Thus, although there is significant differences in the emission factors for indivi dual PAH, the cumulative toxicity-weighted PAH emission factors agr ee reasonably well.Technical Memorandum – Review of HAP Emissi on Factors for Fluid Catalytic Cracking Units November 22, 2013

5 The dioxin/furan emission factors agree quite well between the Prot ocol and Component 4 source tests; however, the inorga nic emission factors are widely different. The emission factor for carbon disulfide is based on a single emission test, as all other test s were below detection limit. As stated previously, it is not appropriate to develop an em ission factor based on one test. Ammonia is not a HAP, so ammonia emissions we re not included in the emission inventory modeling file used to assess risks from petroleum refinery emission sources. There is essentially and order of magnitude ( i.e. , factor of 10) difference in the emission factors for hydrogen chloride, hydrogen cyanide and mercury between the Protocol defaults and the Component 4 source test results. For these HAP, the Protocol default emission factors were based on very limited data and, in the case of hydrogen chloride , source test detection limits. For these HAP, it was deemed appropriate to revi se the emissions inventory mode ling file to incorporate the Component 4 source test emission factors.

5. Corrections Made to the Emission Inventory Modeling File
As seen in Table 1, the average emission factor derived from the Componen t 4 source test data for hydrogen cyanide is approximately a factor of 10 higher than the Protocol emission factor. Given this large difference, the reported emission inventor ies were revised assuming the facilities used the Protocol emission factor. Fac ilities that conducted s ource tests were assigned hydrogen cyanide emissions based on their tested emissions rate. For other facilities, the reported FCCU hydrogen cyanide emissions were multiplied by 10 to better match the emissions that would have been projected had the Component 4 source test data been available at the time the Protocol document was developed.
The average emission factors derived from the Co mponent 4 source test data for mercury and hydrogen chloride are approximately a factor of 10 lower than th e Protocol emission factors. Therefore, the emission inventor y modeling file was also adjust ed to correct FCCU mercury emission estimates to better match the emissi ons that would have been projected had the Component 4 source test data been available at the time the Prot ocol document was developed. Facilities that conducted source tests were assi gned emissions based on their tested emissions rate. For other facilities, the reported FCCU mercury emissions were divided by 10. For FCCU hydrogen chloride emissions, no adjustments were made to the emission inventory modeling file. Hydrogen chloride was below all environmental risk benchmarks and, therefore, limited EPA resources were not used to make these revisions.

6. References
EIA (Energy Information Administration). 2011. Refinery Capacity Report 2011 . Prepared by the Energy Information Administra tion, Washington DC. June 24, 2011.
EPA (U.S. Environmental Protection Agency). 2011. Petroleum Refinery Database, based on Refinery Information Collection Request (I CR) for Calendar Year 2010. September 2011. Docket Item Nos. EPA- HQ-OAR-2010-0682-0061 through 0069.
RTI (RTI International). 2011. Emission Estimation Protocol for Petroleum Refineries

. Version 2.1.1, Final ICR Version Corrected. Pr epared for U.S. Environmental ProtectionTechnical Memorandum – Review of HAP Emissi on Factors for Fluid Catalytic Cracking Units November 22, 2013

6 Agency, Office of Air Quality Planning and St andards, Research Triangle Park, NC. May 2011. Docket Item No. EPA-HQ-OAR-2010- 0682-0060. Most current version also available at http://www.epa.gov/ttn/chief/efpac/protocol/

.