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www.erg.com

MEMORANDUM

TO:	Tonisha Dawson, U.S. EPA/OAQPS/SPPD  -  EPA Office of Air Quality Planning and Standards

FROM:	Eastern Research Group, Inc.

DATE:	October 2018

SUBJECT:	Asphalt Storage Tank Controls - Ample Margin Of Safety Analysis
--------------------------------------------------------------------------------

INTRODUCTION
The EPA determined that the maximum acute risk from the asphalt processing and asphalt roofing manufacturing source category is a hazard quotient (HQ) of 4 caused by formaldehyde emissions from four asphalt storage tanks located at one asphalt processing and asphalt roofing manufacturing facility (EPA 2018). To further reduce the risk (or potential risk) due to emissions of formaldehyde from these four asphalt storage tanks, we evaluated the cost and feasibility of: (1) Installing ductwork and routing the exhaust of the four asphalt storage tanks to an existing thermal incinerator, or (2) installing ductwork and routing the exhaust of the four asphalt storage tanks to a single new packed bed scrubber.
ASPHALT STORAGE TANK DETAILS
The four asphalt storage tanks contributing to an acute HQ of 4 (due to formaldehyde emissions) are identified as T014, T015, T016, and T021, and are located at Owens Corning Roofing and Asphalt, LLC in Ohio. Based on the facility air permit and information we received from the CAA section 114 request (ERG 2017), we determined that these asphalt storage tanks are uncontrolled for organic HAP emissions; however, these tanks are controlled by fiber bed filters in order to comply with the 40 CFR 63, subpart LLLLL opacity standard. 
INSTALLING DUCTWORK AND ROUTING THE EXHAUST OF THE FOUR ASPHALT STORAGE TANKS TO AN EXISTING THERMAL INCINERATOR
We used the methodology from the sixth edition of the EPA Air Pollution Control Cost Manual (EPA, 2002) to calculate the cost to install ductwork to route the exhaust of the four asphalt storage tanks to an existing thermal incinerator. We assumed the duct and elbow material was 304 stainless steel. We also assumed that each asphalt storage tank would need its own duct (i.e., 500 feet of duct per asphalt storage tank) and used a flow rate of 60 actual cubic feet per minute per tank (which is consistent with the flow rate used in the modeling file). The costs were calculated in 2017 dollars and annualized over 20 years using a 4.75% interest rate. The emission reduction and costs calculated for installing ductwork for the facility are summarized in Table 1 below. Appendix A provides the detailed cost algorithms for the total capital investment (TCI) and total annual cost (TAC) to install ductwork, and summarizes the other key parameters used in the analysis to assess impacts.
Table 1. Cost and Environmental Impacts for Installing Ductwork and Routing Exhaust of T014, T015, T016, and T021 to Existing Thermal Incinerator
              (at Owens Corning Roofing and Asphalt, LLC in Ohio)
                                      TCI
                                      ($)
                                      TAC
                                      ($)
                            Formaldehyde Emissions
                                  (tpy) [(A)]
                       Formaldehyde Emission Reductions
                                  (tpy) [(B)]
                              Cost-Effectiveness
                                    ($/ton)
                                     8,640
                                     7,030
                                   6.90E-02
                                   6.87E-02
                                    102,400
[A]	Formaldehyde emissions were provided by the facility as part of the information we received from the CAA section 114 request (ERG 2017). The facility stated these emissions may be overestimated because it assumes all four tanks are being filled at the same time for 8,760 hours per year; this is not a likely scenario.
[B]	A 99.5% formaldehyde removal efficiency was used which is consistent with the combustion efficiency standard in 40 CFR 63, subpart LLLLL for Group 1 asphalt storage tanks.

INSTALLING DUCTWORK AND ROUTING THE EXHAUST OF THE FOUR ASPHALT STORAGE TANKS TO A SINGLE NEW PACKED BED SCRUBBER
The cost estimate to install a packed bed scrubber is based on information from EPA's Control Cost Manual (EPA, 2002). 
The TCI consists of the scrubber tower, packing, and pumps. TCI is driven primarily by gas flowrate. The TCI was updated to 2017 dollars using the Chemical Engineering Plant Cost Index (CEPCI). 
The TAC includes caustic, wastewater disposal, water, electricity, maintenance, labor, capital recovery costs, overhead, administrative, property taxes, and insurance. Unit costs for labor and electricity were updated to 2017 dollars using current estimates. Current operating labor rates were estimated based on the occupational employment statistics available online from the U.S. Bureau of Labor Statistics. We used the CEPCI to convert unit costs for water, wastewater disposal, and caustic to 2017 dollars. 
The emission reduction and costs calculated for installing ductwork and routing the exhaust of the four asphalt storage tanks to a single new packed bed scrubber is summarized in Table 2. Appendix B provides the detailed cost algorithms for the TCI and TAC to install a packed bed scrubber, and summarizes the other key parameters used in the analysis to assess impacts.
Table 2. Cost and Environmental Impacts for Installing Ductwork and Routing Exhaust of T014, T015, T016, and T021 to a Single New Packed Bed Scrubber 
              (at Owens Corning Roofing and Asphalt, LLC in Ohio)
                                      TCI
                                      ($)
                                      TAC
                                      ($)
                            Formaldehyde Emissions
                                  (tpy) [(A)]
                       Formaldehyde Emission Reductions
                                  (tpy) [(B)]
                              Cost-Effectiveness
                                    ($/ton)
                                    153,000
                                    243,000
                                   6.90E-02
                                   6.56E-02
                                   3,705,400
[A]	Formaldehyde emissions were provided by the facility as part of the information we received from the CAA section 114 request (ERG 2017). The facility stated these emissions may be overestimated because it assumes all four tanks are being filled at the same time for 8,760 hours per year; this is not a likely scenario.
[B]	A 95% formaldehyde removal efficiency was used which is consistent with the existing total hydrocarbon mass emission reduction standard in 40 CFR 63, subpart LLLLL for Group 1 asphalt storage tanks.
REFERENCES
EPA. 2002. EPA Air Pollution Control Cost Manual, Section 5.2, Chapter 1. January 2002. EPA/452/B-02-001.
EPA. 2018. Residual Risk Assessment for the Asphalt Processing and Asphalt Roofing Manufacturing Source Categories in Support of the 2018 Risk and Technology Review Proposed Rule. EPA Docket No. EPA - HQ - OAR - 2017 - 0662.
ERG. 2017. Data Received from Clean Air Act Section 114 Request for the Asphalt Processing and Asphalt Roofing Manufacturing Source Categories. EPA Docket No. EPA - HQ - OAR - 2017 - 0662. 
ERG. 2018. Clean Air Act Section 112(d)(6) Review for the Asphalt Processing and Asphalt Roofing Manufacturing Source Categories. EPA Docket No. EPA - HQ - OAR - 2017 - 0662. 


                                  Appendix A
                                       
                                       
                                       
                                       
                                       
                                       
Detailed Cost Algorithms for TCI And TAC of Installing Ductwork and Routing Exhaust of T014, T015, T016, and T021 to Existing Thermal Incinerator (at Owens Corning Roofing and Asphalt, LLC in Ohio)

Ductwork Costs[1]



                               Parameters/Costs
                                     Value
                                   Facility
                                     Notes
Initial Inputs
                                       
                                       
 
     Gas flow rate (acfm)
                                      -- 
                                                                            240
 
     Number of RTOs
                                      -- 
                                                                              1
 
Assumptions
 
 
 
     Duct gas velocity (fpm)
                                                                          4,500
 
See Table 1.3 of OAQPS Cost Manual.
     Duct length (ft)
                                                                          2,000
 
Assume 500 feet per asphalt storage tank
     No. of elbows (#/100 ft)
                                                                              2
 
 
     Total no. of elbows
                                                                             40
 
 
     Duct Diameter (ft)
                                      -- 
                                                                           0.26
 
     Duct Diameter (in)
                                      -- 
                                                                           3.13
 
     Taxes
                                                                           0.03
 
 
     Freight
                                                                           0.05
 
 
     Ductwork installation factor
                                                                           0.25
 
 
Duct Coefficients
 
 
See Table 1.9 of OAQPS Cost Manual.
     a
                                                                          0.322
 
 
     b
                                                                           1.22
 
 
     Straight duct cost ($/ft)
                                      -- 
 $ 1 
 
     Straight duct cost ($)
                                      -- 
$ 2,587 
 
Elbow Coefficients
                                       
 
See Table 1.10 of OAQPS Cost Manual.
     a
                                                                           30.4
 
 
     b
                                                                         0.0594
 
 
     Elbow cost ($/elbow)
                                      -- 
 $ 37 
 
     Elbow cost ($)
                                      -- 
 $ 1,464 
 
Cost Escalator
                                       
 
 
     1993
                                                                          359.2
 
 
     2017
                                                                          567.5
 
 
     Interest rate
                                                                         0.0475
 
 
     Equipment life (yrs)
                                                                             20
 
 
     CRF
                                                                         0.0786
 
 
Total Ductwork Cost
                                      -- 
$ 6,400 
 
     Purchased equipment cost
                                      -- 
$ 6,912 
 
Total Capital Investment
                                       
 
 
     Per RTO
                                      -- 
 $ 8,640 
 
     Per facility
                                      -- 
 $ 8,640 
 
 
 
 
 
Direct Annual Cost
                                       
 
 
     Straight duct friction losses (in. W.C.)
                                      -- 
                                                                         199.39
 
     Velocity Pressure (VP)
                                                                           1.26
 
 
     k Value for 90 Degree Elbows, k90
                                                                           0.33
 
 
     k Value for 45 Degree Elbows, k45
                                                                          0.165
 
 
     Elbow friction losses (in. W.C.)
                                      -- 
                                                                          12.43
 
     Total friction losses (in. W.C.)
                                      -- 
                                                                         211.82
 
     Price of electricity ($/kwh)
                                                                         0.0689
 
 
     Motor efficiency
                                                                            0.6
 
 
     Operating factor (hr/yr)
                                                                           8760
 
 
     Electricity cost ($/yr)
                                      -- 
 $ 6,009 
 
Indirect Annual Cost
 
 
 
     Property taxes
                                                                           0.01
 $ 86 
 
     Insurance
                                                                           0.01
 $ 86 
 
     G&A
                                                                           0.02
 $ 173 
 
     Capital recovery
                                      -- 
 $ 679 
 
Total Annual Cost
 
 
 
     Per RTO
                                      -- 
$ 7,033 
 
     Per facility
                                      -- 
$ 7,033 
 
[1] We used the methodology from the sixth edition of the EPA Air Pollution Control Cost Manual (EPA, 2002) to calculate the cost to install ductwork. We assumed the duct and elbow material was 304 stainless steel. The costs were calculated in 2016 dollars and annualized over 20 years using a 4.75% interest rate. 

                                  Appendix B
                                       
                                       
                                       
                                       
                                       
                                       
Detailed Cost Algorithms for TCI And TAC of Installing Ductwork and Routing Exhaust of T014, T015, T016, and T021 to a Single New Packed Bed Scrubber (at Owens Corning Roofing and Asphalt, LLC in Ohio)
                                       
                                   Parameter
                               Equation Variable
                                   Equation
                                 Calculations
STREAM AND INPUT DATA
 
                                       
                                       
Facility Name
 
                                       
                            Owens Corning Roofing and Asphalt, LLC (1652050040)
                              TOTAL FOR INDUSTRY
Emission Point
 
 
                                Combined Stacks from T014, T015, T016, and T021
 
State
 
 
                                                                             OH
 
Flowrate (acfm)
AQtot
Facility-specific, based on modeling file
                                                                            240
 
Flowrate (acfm) (Per Scrubber)
AQ
=AQtot / #Scr
                                                                            240
 
Operating Hrs
H
Avg. of survey responses
                                                                           8760
 
Percent FHYD Reduction Required
%Ctrl
 
                                                                             95
 
Temp (F)
Tf
Facility-specific, based on modeling file
                                                                            300
 
Temp (K)
T
=(Tf + 459.67) * 5/9
                                                                            422
 
Inlet FHYD Loading (lb/hr)
In FHYDtot
Facility-specific, based on modeling file
                                                                    0.962774804
 
Inlet FHYD Loading (lb/hr) (Per Scrubber)
In FHYDscr
= In FHYDtot / #Scr
                                                                    0.962774804
 
Inlet FHYD Loading (mole fraction)
In FHYDm
= (In FHYDscr / 60 / MWFHYD) / (AQ * Dens / MWg)
                                                                    1.26895E-06
 
CAPITAL COST CALCULATIONS
 
                                       
                                       
Scrubber Diameter Exponent (S1)
SDC
= (-0.915 - SQRT(-1.144359 - (1.188 * (LOG10((mm * Fp * ((ui / 2.42) ^ 0.2) * MWR^2  * ap^2) / (12960000 * f^2 * 32.2)))))) / (-0.594)
                                                                          -1.32
 
Ds (Scrubber Diameter)
Ds
= SQRT((240 * Dg * AQ * 10^SDC) / (MWR * Dl * ap * PI * SQRT((Dg / Dl))))
                                                                            0.9
 
Hpack (Packing Constant)
Hpack
= LN((In FHYDm / ((In FHYDm * (100 - %Ctrl)) / (100-In FHYDm * %Ctrl)))) * (((x * (HpackA ^ BBB)) / (HpackB ^ g)) * (ui^g) / (ug^BBB) * SQRT(HpackC) + ((1 / AFT) * (t * (HpackD ^ bb) * SQRT(HpackE))))
                                                                           35.0
 
Number of Packed Scrubbers
#Scr
Max flowrate per scrubber is 74,800 acfm
                                                                             1 
 
Hpack - A
HpackA
= (240 *  Dg * AQ) / (PI * Ds^2)
                                                                       1,582.6 
 
Hpack - B
HpackB
= MWR * D * ap
                                                                         2,271 
 
Hpack C
HpackC
= ug / (Dg * Dfg)
                                                                          0.89 
 
Hpack D
HpackD
= (MWR * Dl * ap) / ui
                                                                         1,052 
 
Hpack E
HpackE
= ui / (Dl * Dfl)
                                                                         446.6 
 
TCI - Pack
TCIp
= #Scr * 0.649 * Cp * Hpack * PI * Ds^2 * (1.0506 * 109.4 / 100) * (2017 CEPCI / 389.5)
                                      $                                  1,963 
 
TCI - Pump
TCIpump
= #Scr * 0.0312 * MWR * ap * PI * Ds^2 * CFpump * m * (1.0506 * 109.4 / 100) * (2017 CEPCI / 389.5)
                                     $                                     118 
 
TCI - Tower
TCItower
= #Scr * ((417.956 * m * PI * Ds * Hpack) + (453.7808 * m * PI * Ds^2) + (838.8974 * m * PI * Ds)) * (1.0506 * 109.4 / 100) * (2017 CEPCI / 389.5)
                                       $                                75,695 
 
TCI (scrubber)
TCIscrub
= (TCItower + TCIpump + TCIp) * (Retrofit Factor of 1.4)
                                        $                              108,886 
 
Number of Ductlines
ND
Calculate such that max flowrate per ductline is 154,042 acfm
                                                                             1 
                                       
Duct Diameter (ft)
Dd
= 1.128 x (AQ / ut)^0.5
                                                                           0.32
 
TCI - Duct - SS
TCIduct
= #Scr * ND * (1.458 * ((0.39 * ((Dd / ND)^2) * 3.14159 * L) + (74.2 * L * Ne_Ld * EXP(0.8016 * (Dd / ND))) + (23 * EXP(0.6804 * (Dd / ND))) + (af * (Df^b)))) * (2017 CEPCI / 389.5) * (Retrofit factor of 1.4)
                                       $                                20,470 
                                       
Total Monitoring Cost
TCImon
Parametric monitor capital cost, default applied to all facilities
                                       $                                24,100 
                                       
TCI (Total)
 
= TCIscrub + TCIduct + TCImon
 $                            153,456 
 $    153,456 
ANNUAL COST CALCULATIONS
 
                                       
                                       
Cost of Caustic
Ccaus
= #Scr * (0.03 * AQ * Dg * (In FHYDm - (In FHYDm * (100 - %Ctrl) / (100 - In FHYDm * %Ctrl))) * _SR1 * MWc * H * CFc / MWg)
                                   $                                         3 
 
Cost of WW disposal
Cdis
= #Scr * (7.194 * D7 * Dg * (In FHYDm -(In FHYDm * (100 - %Ctrl) / (100 - In FHYDm * %Ctrl))) * _SR2 * MWs * (1 / BF) * H * CFww / MWg)
                                   $                                         0 
 
Cost of solvent (water)
Csolv
= #Scr * (Cdis * (CFwt / CFww))
                                   $                                         0 
 
Cost of labor and supervisor
Clab
= #Scr * (0.07188 * H * CFlab)
                                       $                                50,168 
 
Cost of maintenance
Cmain
= #Scr * (0.125 * H * CFmain)
                                       $                                87,243 
 
Electricity Amount (Fan)
ElecFan
= (0.000117 * AQ * H * (((Hpack * (AQ^2) * cpc * Dg * (10^(j * MWR * Dl * ap / 3600))) / (225* PI^2 * Ds^4)) + (0.136 * (( 1 / Dd)^1.18) *((ut / 1000)^1.8) * (L / 100) + (L) * (Ne_Ld) * k * ((ut / 4016)^2)))) / ef
                                       $                                17,631 
 
Electricity Amount (Pump)
ElecPump
= (0.00000585 * H * PI * Ds^2 * MWR * ap * Pp) / Ep
                                     $                                     413 
 
Electricity Cost (Total)
ElecTot
 = #Scr * CFelec * (ElecFan + ElecPump)
                                      $                                  1,247 
 
Variable Costs
Var
= CCaus + Cdis + Csolv + Clab + Cmain + ElecTot
                                        $                              138,661 
 
Capital Recovery
CapRec
= (TCIscrub * ((I*((1 + I) ^ n)) / (((1 + I) ^ n) - 1)))
                                       $                                10,314 
 
Overhead Cost
Ovrhd
= 0.6 * (Clab + Cmain)
                                       $                                82,447 
 
Administrative Cost
Admin
= 0.02 * TCIscrub
                                      $                                  2,178 
 
Property Tax
Tax
= 0.01 * TCIscrub
                                      $                                  1,089 
 
Insurance
Ins
= 0.01 * TCIscrub
                                      $                                  1,089 
 
Fixed Costs
Fix
= CapRec + Ovrhd + Admin + Tax + Ins
                                       $                                97,116 
 
TAC (scrubber)
TACscr
= Var + Fix
                                        $                              235,777 
 
CRF duct
CRFduct
 
                                                                          0.079
 
Duct - Capital Recovery
DuctCR
= TCIduct * CRFduct
                                      $                                  1,608 
                                       
Duct - Administrative Cost
DuctAdmin
= TCIduct * 0.02
                                     $                                     409 
                                       
Duct - Property Tax
DuctTax
= TCIduct * 0.01
                                     $                                     205 
                                       
Duct - Insurance
DuctIns
= TCIduct * 0.01
                                     $                                     205 
                                       
TAC - Duct
TACduc
= DuctCR + DuctAdmin + DuctTax + DuctIns
                                      $                                  2,427 
 
Annual Monitoring Cost
TACmon
Parametric monitor annual cost, default applied to all facilities
                                      $                                  5,200 
 
TAC (Total)
TAC
= TACscr + TACduc + TACmon
 $                            243,403 
 $    243,403 
EMISSION REDUCTIONS AND COST-EFFECTIVENESS
                                       
                                       
Lbs of FHYD Removed per Yr
 
= H * In HDlscr * (%Ctrl / 100)
                                                                         8,012 
              8,012 
Dollars per Ton of FHYD Removed
 
 
 $                              60,758 
 $       60,758 
                                       
                           PACKED SCRUBBER DEFAULTS
Variable
COMMON DEFAULTS - PACKED SCRUBBER
 
I
I = interest rate

 
                                                                         0.0475
2017 CEPCI
2017 CEPCI

 
                                                                          567.5
Dg
Dg = density of gas, lb/ft3
 
                                                                         0.0709
Ne_Ld
Ne/LD = # of elbows per length of duct
                                                                           0.02
L
L = length of ductwork
 
                                                                            500
MWR
MWR = minimum wetting rate, ft2/hr
                                                                            1.3
ut
ut = gas transport velocity, ft/min
                                                                           3000
Dl
Dl = density of liquid, lb/ft3

                                                                           62.4
ap
a = packing constant, ft2/ft3
 
                                                                             28
Variable
DEFAULTS - TOTAL ANNUAL COST -- PACKED SCRUBBER 
n
n = life of equipment, yrs
 
                                                                             15
SR1
SR1 = moles caustic/moles pollutant
                                                                            0.5
MWc
MWc = caustic molec wt, lb/lb-mole
                                                                             62
CFc
Cfc = cost factor for caustic, $/ton
                                                                            450
MWg
MWg = gas molecular weight, lb/lb-mole
                                                                             29
Dens
gas density, lb/ft3

 
                                                                          50.88
MWf
Formaldehyde molecular weight, lb/lbmol
 
                                                                         30.031
SR2
SR2 = moles salt/moles Formaldehyde
 
                                                                              1
MWs
MWs = salt molecular weight, lb/lb-mole
                                                                           58.5
BF
BF = fraction of waste stream treated
                                                                            0.1
CFww
CFww  = cost factor for ww disposal, $/gal
                                                                         0.0054
CFwt
CFwt = cost factor for water, $/gal
                                                                       0.000591
CFlab
CFlab = cost factor for labor, $/hr
                                                                          79.67
CFmain
CFmain = cost factor for maintenance, $/hr
                                                                          79.67
 Variable
DEFAULTS - ELECTRICITY - PACKED SCRUBBER
CFelec
CFelec = cost factor for electricy, $/kw-hr
                                                                        0.06910
Pp
Pp = pressure of pump, ft of H20
                                                                             60
Ep
Ep = efficiency of pump

                                                                            0.7
cpc
cpc = packing constant

                                                                           0.24
j
j = packing constant


                                                                           0.17
k
k = friction loss factor for elbow

                                                                           0.35
ef
ef = efficiency of fan
 
 
                                                                            0.7
 Variable
DEFAULTS - DUCTWORK - PACKED SCRUBBER
af
af = fan coefficient


                                                                           22.1
b
b = fan exponent


                                                                           1.55
Df
Df = fan diameter, inches

                                                                           36.5
n_duct
n_duct = life of equipment, yrs
 
                                                                             20
Variable
DEFAULTS - TCI - PACKED SCRUBBER
                                       
m
m = factor to convert from FRP to other material
                                                                              1
mm
mm = ratio of solvent density to water density
                                                                              1
Fp
Fp = packing factor


                                                                             65
ui
ui = viscosity of liquid, lb/ft-hr

                                                                           2.16
f
f = flooding factor


                                                                            0.7
ug
ug = viscosity of gas, lb/ft-hr

                                                                          0.044
Dfg
Dfg = diffusivity of pollutant in gas, ft2/hr
                                                                          0.698
Dfl
Dfl = diffusivity of pollutant in liquid, ft2/hr
                                                                       0.000078
AFT
AFT = absorption factor

                                                                             17
x
x = packing constant


                                                                           3.82
t
t = packing constant


                                                                         0.0125
g
g = packing constant


                                                                           0.45
BBB
BBB = packing constant

                                                                           0.41
bb
b = packing constant


                                                                           0.22
Cp
Cp = packing cost factor, $/ft3

                                                                             20
CFpump
CFpump = cost factor for pump, $/gpm
 
 
 
                                                                          24.06
                                       
