AQ_F_0800112_20220805_PRMT_PmtRvw

NORTH CAROLINA DIVISION OF Region: Washington Regional Office
AIR QUALITY County: Bertie
Application Review NC Facility ID: 0800112
Inspector's Name:
Issue Date:August 5,2022 Date of Last Inspection:
Com liance Code:
Facility Data Permit Applicability(this application only)
Applicant(Facility's Name): GreenGas USA SIP: 2D(.0202, .0515, .0516.0521, .0535, .0540,
.0611, .1100)and 2Q.0711
Facility Address: NSPS:
GreenGas USA NESHAP:
3539 Governors Road PSD:
Lewiston,NC 29405 PSD Avoidance:
NC Toxics:
SIC:4922/Natural Gas Transmission 112(r):
NAILS: 486210/Pipeline Transportation of Natural Gas Other:
Facility Classification: Before: N/A After: Synthetic Minor
Fee Classification: Before: N/A After: Synthetic Minor
Contact Data Application Data
Facility Contact Authorized Contact Technical Contact Application Number: 0800112.22A
Becky Atkinson Becky Atkinson Becky Atkinson Date Received: 05/16/2022
Managing Director Managing Director Managing Director Application Type: Greenfield Facility
[phone] [phone] [phone] Application Schedule: State
4900 O'Hear Avenue 4900 O'Hear Avenue 4900 O'Hear Avenue Existing Permit Data
Charleston, SC Charleston,SC Charleston,SC Existing Permit Number: N/A
29405+5081 29405+5081 29405+5081 Existing Permit Issue Date: N/A
Existing Permit Expiration Date: N/A
Review Engineer: Robert Bright Comments/Recommendations:
Issue 10744/R00
Review Engineer's Signature: Date:August 5,2022 Permit Issue Date: August 5,2022
Permit Expiration Date: May 31,2030
Application Summary
On May 12,2022,WaRO received an application from GreenGas USA to construct and operate a renewable
natural gas facility(RNG)at the existing Perdue poultry processing facility(DAQ ID Number 0800081) in
Lewiston,Bertie County,North Carolina. The facility completed e-pay for the application on May 17, 2022. The
facility is requesting a Synthetic Minor permit and will be constructed in two phases. I used the permit and permit
review for Optima TH(DAQ ID: 0900096;Fayetteville Regional Office) as a reference for processing this
application.
Process description
Note: The gases have already undergone anaerobic digestion in the lagoons prior to collection,though the
digestors will be modified to facilitate the proposed gas collection system.A process flow diagram is given in
Appendix C of the application.
Phase one consists of collecting the gases from the water treatment lagoons,treating a portion with an"iron
sponge"to remove 1-12S and then routing to a flare(the other portion bypasses this treatment and is mixed with the
treated portion prior to the flare)while the renewable natural gas(RNG)process is installed. It is important to
note that the"iron sponge"(listed as adsorber in the permit) is considered a control device and the concentration
of 1-12S exiting should not exceed 1,000 ppm(originally 1,500 ppm—explanation given in application chronology)
per Tony Jabon(Tony) ,who prepared the application.
Phase two is the installation/operation of the RNG facility(two parallel lines) consisting of routing the gas
through(1)the"iron sponge"adsorber(2)gas compression, (3)Pressure Swing(Molecular Gate)to remove

carbon monoxide,hydrogen sulfide,volatile organic compounds, and water(tailgas), (4)cooling and compressing
the product gas to required specification for the existing natural gas pipeline,with tailgas from each line routed to
its own flare(not combusted).
Tailgas combustion will utilize natural gas as a pilot fuel and will occur for any collected gas that has a H2S
concentration greater than 1,000 ppm(originally 1,500 ppm—explanation given in application chronology). The
flare will also be used during plant startup and is considered a control device during the two scenarios presented.
Note in the process of application review GreenGas USA changed the ID numbers for the adsorber and flares.
Application Chronology
Application received 5/12/2022
E-pay received 5/17/2022
Application Acknowledgement letter 5/28/2022
Permit draft submitted to facility for review 7/29/2022
Comments received by facility 8/03/2022
On August 2,2022,1 discussed the draft permit and review with Becky Atkinson of GreenGas USA(Becky)
and Tony Jabon of Trinity Consultants(Tony),with particular focus on the flare and iron sponge monitoring
requirements. Per the discussion,the maximum H2S concentration entering the flare or RNG process will be
lowered to 1,000 ppm to reduce S02 emissions from the flare. Tony said he would prepare revised
calculations and requested edits to the draft permit. On August 3,2022,WaRO received the revised SO2
emissions calculations and requested edits. They have been incorporated into the application package. The
permit writer concurs with the revised calculations and has incorporated the requested changes into the
permit.
Permit submitted for review 8/04/2022
Permit Issued 8/05/2022
Permit History
There is no prior air quality permit as this is a greenfield facility.
NSPS,NESHAPS,PSD,Attainment Status,and 112r
• NSPS—A review of 40 CFR Part 60 indicated that there are no applicable subparts. Note that
Subpart OOOOa is not applicable because the facility does not meet the definition for Crude Oil and
Natural Gas Production source category.
• NESHAPS—A review of 40 CFR Parts 61 and 63 indicated that there are no applicable subparts.
Note that Subpart HHH is not applicable because the facility does not meet the definition for natural
gas transmission and is not a major source for HAPS.
• PSD—The facility is not subject to PSD as it is not one of the PSD-applicable 28 source categories
and the potential emissions will not exceed the 250-ton applicability threshold. The NOx and S02
emission increases via facility operation are 6.40 and 6.84 pounds per hour,respectively. RCO will
be advised of the increases.
• Attainment Status-This facility is in an attainment area.
• 112r—The facility does not handle, store,or use any 112R pollutants in sufficient quantity to be
subject to this regulation.
Facility Compliance Status
The facility is a greenfield that has not been constructed or operated.
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Regulatory Review
2D.0202 "Registration of Air Pollution Sources"
The Director has the authority to require the registration of air pollution sources and require them to submit
information about the source. It is under this Rule that the Division is requiring facilities to submit an
emissions inventory 90 days before a Permit expires. The inventory will be for calendar year 2029.
2D.0515 "Particulates from Miscellaneous Industrial Processes"
Actual particulate emissions rate shall not exceed the allowable rate determined by the equations outlined in the
regulation. Compliance is expected as particulate emissions from the combustion of the tailgas and natural
gas is considered negligible.
2D.0516 "Sulfur Dioxide Emissions from Combustion Sources"
Sulfur dioxide emissions are limited to 2.3 lbs S02/MM Btu heat input.
Initial permit review:
Per Appendix D of the application,the worst-case scenario is the combustion of tailgas,which has an emission
rate of 2.29 pounds per million Btu,which rounds up to 2.3. Discussions with the consultant note that the
emissions being close to the limit are a result of the portion of collected lagoon gases that bypass the iron sponge,
and the necessity that the H2S content of the gas exiting the iron sponge is less than 1,500 ppm.
For this reason,the 112S concentration exiting the"iron sponge"will monitored daily. In addition,the SO2
emissions should be monitored during startup and when tailgas is combusted as described in the Optima TH
Permit R00.
From the Optima TH Permit R00 application review by Rahul Thaker of RCO-Permits:
It should be noted that in general, it is technically infeasible to measure the actual emission rate for S02 (or for any
other pollutant) accurately for open flares such as the proposed flare at Optima. Thus, in lieu of an actual source
sampling,the DAQ proposes the following monitoring approach.
The Permittee will be required to determine the S02 emission rate (million Btu/hr) for the flare for all operating
scenarios(normal operation,bypass operation,and off-spec operation)on a 24-hour block average basis,as below for
each day the facility is in operation. If any 24-hour block average S02 emission rate (million Btu/hr) exceeds the
above emission standard(2.3 lbs/million Btu),the Permittee will be deemed to have violated this requirement.
Emission Rate Monitoring
Equation 1
S02 emission rate,lb/million Btu
{S02 formed due to destruction of 112S and other trace sulfur compounds in biogas and tail gas by flare} +
{S02 formed due to combustion of fuel in flare}
1[(60 *MW*P *V)/(R*T)] *ill / {HI} + 10.0011 + {EF} / {HV}
Where,
MW=molecular weight of S02,lb/lb-mot=64.06 lb/lb-mol
P=absolute pressure,psia= 14.7 psia(reference condition of 1 atmosphere)
V=average daily actual flow rate of H2S in both biogas and tail gas,scfm
R=ideal gas law constant= 10.73 psia-ft3/lb-m OR
T=absolute temperature,°R =528°R(reference condition of 20 IQ
i1=destruction efficiency of flare for 112S,percent=98 percent
HI = average daily actual heat input rate (biogas, tail gas, product gasl, propane, and natural gas) for
flare,million Btu/hr
'For off-spec scenario only.
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EF=SO2 emission factor for combustion of fuel in flare,lb/106 sft3=0.60 lb/106 sft3
HV=weighted average fuel heating value (biogas,tail gas,product gas2,propane, and natural gas),based
on the monthly measured or fuel-supplier's heating values for each of the fuels and actual fuel flow rate for
each to flare,Btu/sft3
0.001 = default SO2 emission rate for trace sulfur compounds in biogas and tail gas in lb/million Btu,unless
and until the facility can demonstrate,through sampling,that an alternative value is more representative
The above default SO2 emission rate for trace sulfur compounds is based upon a similar biogas generation project,
recently approved by the DAQ for Align RNG, LLC — BF Grady Road, Turkey, NC (Air Permit No. 10644R00,
January 6,2021). The subject permit for this facility includes a default SO2 emission rate of 0.05 lb/hr for trace sulfur
compounds in biogas and tail gas. Using the maximum heat input rate of 50 million Btu/hr for the proposed flare at
Optima TH,the equivalent emission rate of 0.001 lb/million Btu is estimated.
The DAQ approval of 98 percent destruction efficiency(instead of applicant-assumed 99 percent)for H2S is justified
with supporting rationale in Sections 7 and 10 below and shall be used for monitoring of SO2 emissions.
For each of the hourly operation of flare, flow rate of H2S as Vh (scfm) shall be determined as below in Equation 2
and the average of all calculated hourly values of the day shall be determined and input as average daily value of V
(scfm)in the Equation 1 above:
Equation 2
Vh,scfm= (%by volume H2S in biogas*amount of biogas,scfm)+(%by volume H2S in tail gas*amount of
tail gas,scfm)
For each of the hourly operation of flare,heat input for flare as HIh(million Btu/hr)shall be determined as follows in
Equation 3 and the average of all calculated hourly values for the day shall be determined and input as average daily
value of HI(million Btu/hr)in the Equation 1 above:
Equation 3
HIh,million Btu/hr= {{(biogas flow rate,scfm)*(biogas heating value(HHV),Btu/sft3)} + {(tail gas flow rate,
scfm) *(tail gas heating value(HHV),Btu/sft3)I + {(product gas flow rate,scfin) *
(product gas heating value(HHV),Btu/sft3)}3+ {(propane flow rate,scfm) *(propane
heating value(HHV),Btu/sft3)} + {(natural gas flow rate,scfm) * (natural gas heating
value(HHV),Btu/sft3)}} * 160 min/hr}
Monitoring
• The Permittee will be required to perform the following monitoring on an hourly basis of each day the facility is
operating:
■ Measure the amount of biogas entering the GUS(scfin)using a flow monitor.
■ Measure the amount of biogas entering the flare(scfm),bypassing the GUS,using a flow meter.
■ Measure the tail gas leaving the GUS(scfin).
■ Determine the product gas leaving the GUS(scfm)using the mass balance method and the data collected for
the amounts of biogas and tail gas as above.
■ Measure the amount of propane and natural gas entering the flare(scfm).
■ Measure the concentrations of both methane(%volume) and H2S (%volume) in the biogas using a biogas
analyzer(gas chromatograph).
■ Measure the methane concentration(%volume)in the product gas using a gas analyzer.
2 Id.
3 Id.
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■ Determine the concentration of H2S(%volume)in the tail gas using the biogas data for H2S as above.
• The Permittee will be required to analyze biogas and tail gas samples once every month to determine their heating
values(HHV),Btu/sft3.
• The Permittee will be required to verify that the flare is designed and operated as below within 180 days of the
issuance of an air quality permit:
■ Flare shall be designed for and operated with no visible emissions as determined by the Method 22 of
Appendix A to 40 CFR 60, except for periods not to exceed a total of 5 minutes during any 2 consecutive
hours. The observation period is 2 hours and shall be used according to Method 22.
■ Flare shall be operated with a flame present at all times,as determined by the following method. The presence
of a flare pilot flame shall be monitored using a thermocouple or any other equivalent device to detect the
presence of a flame.
■ Flare shall meet the following heat content and maximum tip velocity specifications as below:
o Flare shall be used only with the net heating value of the gas being combusted being 300 Btu/scf or
greater if the flare is steam-assisted or air-assisted; or with the net heating value of the gas being
combusted being 200 Btu/scf or greater if the flare is non-assisted.
o If the flare is steam-assisted or non-assisted flare, it shall be designed for and operated with an exit
velocity less than 60 ft/sec with the exceptions as provided below.
o If the flare is steam-assisted or non-assisted flare, it shall be designed for and operated with an exit
velocity greater than 60 ft/sec but less than 400 ft/sec,provided the net heating value of the gas being
combusted is greater than 1,000 Btu/scf.
o Steam-assisted or non-assisted flare designed for and operated with an exit velocity less than 400 ft/sec
is permitted as long as the exit velocity is less than the velocity,Vmax,as determined below.
o The net heating value of the gas being combusted in a flare shall be calculated using the following
equation:
n
HT 4 K t C1HI
i■I
where:
HT= Net heating value of the sample,MJ/scm;where the net enthalpy per mole of offgas is
based on combustion at 25 °C and 760 mm Hg,but the standard temperature for
determining the volume corresponding toone mole is 20°C;
K * Constant, � 5 1 J �oJ K�
1.740 � 10- Rpm scm coca +
w1here the standard temperature for (gnoie� is 20°CF
scan
Ci= Concentration of sample component i in ppm on a wet basis,as measured for organics by
Reference Method 18 and measured for hydrogen and carbon monoxide by ASTM D 1946-
77 or 90(Reapproved 1994);
and
Hi= Net heat of combustion of sample component i,kcal/g mole at 25 °C and 760 mm Hg.
The heats of combustion may be determined using ASTM D2382-76 or 88 or D4809-95
if published values are not available or cannot be calculated.
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o The actual exit velocity of a flare shall be determined by dividing the volumetric flowratc (in units of
standard temperature and pressure),as determined by Reference Methods 2,2A,2C,or 2D of Appendix
A to 40 CFR 60,as appropriate;by the unobstructed(free)cross sectional area of the flare tip.
o The maximum permitted velocity,Vmax,for the flare shall be determined by the following equation.
Logio(V.)=(HT+28.8)/31.7
Vmax=Maximum permitted velocity,M/sec
28.8=Constant
31.7=Constant
HT=The net heating value as determined above.
o If the flare is air-assisted flare, it shall be designed and operated with an exit velocity less than the
velocity,Vmax,as determined by the following method:
Vmax=8.706+0.7084(HT)
Vmax=Maximum permitted velocity,m/sec
8.706=Constant
0.7084=Constant
HT=The net heating value as determined above.
Recordkeeping and Reporting
The Permittee will be required to keep records of all monitoring activities as described above. The Permittce will be
required to report the S02 emissions rates of flare on a 6-month basis (January-June and July-December)within 30
days of end of each of the 6-month periods,containing a summary of average S02 emission rates(lb/million Btu)for
each day.
Revised calculations and iron sponge changes:
By reduction of the 112S concentration to 1,000 ppm, sulfur dioxide emissions are reduced to 1.53 pounds per
million Btu. The monitoring and recordkeeping requirements will be changed to:
Monitoring/Recordkeeping [15ANCAC 02Q .0308(a)]
b. The Permittee shall monitor the H2S concentration prior to combustion in the flare (F-1)in Phase 1 and prior
to either input into the RNG system or combustion in the flare in Phase 2 on a weekly basis to ensure
concentration does not exceed 1,000 ppm by weight. The Permittee may elect to collect more frequent
readings and take the weekly average of those readings for the purpose of compliance as long as those
readings are taken on a regular basis and not increased to avoid a non-compliance event.
At a minimum the Permittee shall perform semi-annual calibration of each concentration gauge and maintain
copies of these calibrations.
Reporting [15A NCAC 02Q .0308(a)]
c. The Permittee shall submit a report within 180 days of the issuance of the air quality permit 10673R00,
verifying that the candlestick flare(ID No. F-1 and F-2) is designed and operated as per the requirements in
Section A.4.a. above.
WaRO's review of the revised calculations indicate the worst-case S02 emissions(combustion of tailgas)is 1.53
pounds per million Btu,which constitutes a 34%reduction from the 2.3 pounds per million Btu outlined in the
initial permit application. For this reason,WaRO believes the emissions are low enough to not require the
monitoring of sulfur dioxide emissions. The combustion of tailgas is expected to be very minimal. Compliance
is expected as WaRO's review of the revised.
2D.0521 "Control of Visible Emissions"
All sources are limited to 20%opacity. Compliance is expected and will be confirmed by the facility by
conducting a Method 22 observation and confirmed by DAQ from inspection.
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2D.0535 "Excess Emissions Reporting and Malfunctions"
The facility is required to report excess emissions which last for more than four hours. The emissions may be
determined as excusable by the Director if they result from a malfunction or other abnormal conditions.
Compliance is expected.
2D.0540 "Particulates from Fugitive Dust Emission Sources"
The facility may not generate fugitive dusts that go beyond the property boundary and cause a substantive
complaint. Fugitive emissions are those that don't pass through a stack or vent and are generated within plant
property boundaries. Fugitive emissions include loading areas, stockpiles,parking lots, and haul roads.
Compliance is expected and will be confirmed during facility inspection.
2D.0611 "Monitoring Emissions from Other Sources"—(Permit Specific Condition A.8)
This rule requires the facility to keep adequate records to show compliance with all applicable rules. Under this
rule,the permit specifically requires the facility to perform I&M inspections on the iron sponge and flare.
2Q.0711 "Toxic Pollutant Emission Rates" / 2D.1100 "Control of Toxic Air Pollutants"
1­12S is the only NC toxic emitted more than its TPER and a dispersion model was submitted with the application.
Formaldehyde was another TAP of concern but was determined to be below its respective TPER. Nancy Jones of
AQAB reviewed the modeling and issued her review on July 22, 2022,noting a demonstration of compliance. The
review noted that the emission rate of 112.81 pounds per day made up 99.9%of the acceptable ambient level.
Compliance is expected as the model was performed based on 1,500 ppm H2S concentration that has now been
reduced to 1,000 ppm.
2D.1806 "Control and Prohibition of Odorous Emissions"
This rule requires the facility to implement management practices to prevent objectionable odors from the facility
to move beyond the facility property boundaries. Compliance is expected and will be confirmed during facility
inspection.
2Q.0315 "Synthetic Minor Facilities"
The facility has requested to operate via a synthetic minor permit with limitations on sulfur dioxide emissions.
Note that H2S is not a federal HAP is not subject to the 10-ton individual applicability threshold. The monitoring,
recordkeeping and reporting associated with the iron sponge and flare prescribed for 2D .0516(Permit Specific
Condition A.4)will be the compliance methodology.
Emissions Review
Facility-wide emissions are listed below depending on the scenario: Phase 1 (combustion by flare),Phase 2
(no combustion)and Phase 2 (combustion during startup and of tailgas). The emissions listed below are based
on the Texas Commission on Environmental Quality's guidance for New Source Review Emissions
Calculations and are presented in Appendix D of the application.
Note: The PTEs listed are from the original permit application and are now lower due to the decreased H2S
concentration. The permit writer is leaving the original numbers with notations on the reduced SO2 emissions.
Phase 1 (combustion by flare—Table D.2a) :
Phase 1 -Treat and Flare,High Flow: Gas feed from each of two lagoons(Emission Source IDs LAG1 and
LAG2)to dedicated iron sponge units for removal of 1­12S(Control Device IDs SP1A and SP1B). Emissions are
from individual flares(FLR1A and FLR1 B). Flaring emissions are based on the quantity of raw gas from each
lagoon(700 scfm),the concentration of 1­12S in the raw gas (8,000 ppm),the iron sponge 1­12S removal efficiency
(81%at max.emission rate)and the flare combustion efficiency(98%).Annual emissions are based on
continuous operation 8,760 hours per year.
Potential Emissions
Pollutant tons/ r
CO 55.98
NOx 28.04
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S02 89.81 —now 59.98
VOC 0.03
Hydrogen sulfide 23.37—now 15.58
HAPs 0.03
Phase two(no combustion):
Phase 2-Two RNG Facilities, With No Tail Gas Combustion: Gas feed from each of two lagoons(Emission
Source IDs LAG1 and LAG2)to dedicated iron sponge units for removal of H2S (Control Device IDs SP1A and
SP1 B)to two RNG facilities(Emission Source IDs RNG1 and RNG2). Tail gas is emitted from flares(FLR2A
and FLR26)without combustion. Emissions are based on the quantity of raw gas from each lagoon(700 scfm
to each RNG facility)and the concentration of H2S in the raw gas (8,000 ppm), and the iron sponge 112S
removal efficiency(81% at max emission rate).Annual emissions are based on continuous operation 8,760
hours per year.
Potential Emissions
Pollutant (tons/ r)
CO 0
NOx 0
S02 0
VOC 0
Hydrogen sulfide 19.82
HAPs 0
Phase 2(with combustion)
Phase 2-Two RNG Facilities,With Tail Gas Combustion: Gas feed from each of two lagoons(Emission
Source IDs LAG1 and LAG2)to dedicated iron sponge units for removal of H2S (Control Device IDs SP1A and
SP1B).Treated gas from the iron sponge units is sent to RNG treatment(Emission Source IDs RNG1 and
RNG2). Tail gas from the RNG facilities is combusted in flares(FLR2A and FLR2B). Emissions are based on
the quantity of treated gas from each lagoon/iron sponge (700 scfm to each RNG facility)and the concentration
of H2S in the PSA tail gas(2,900 ppm)with combustion at the flares. Annual emissions are based on
continuous operation 8760 hours per year.
Potential Emissions
Pollutant (tons/ r)
CO 8.49
NOx 4.25
S02 70.70—now 47.13
VOC 0.0113
Hydrogen sulfide 0.77—now 0.51
HAPs 0.0113
While in none of the scenarios presented do the emissions exceed the 100-ton Title V applicability threshold
for which limitations would be required,the facility requests limitations to ensure the emissions are below the
threshold.
Stipulation Review:
The permit will be created using the latest conditions from the Permit Writer. A copy of the DRAFT permit
submitted to the facility is stored on the WaRO SharePoint site at: DRAFT.
Conclusions, Comments, and Recommendations
I recommend issuance of Air Permit No. 10744R00 to GreenGas USA.
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