Document Ew98JXpEzbnwON71Y6Rqz2ex
EPA Inspection Report - Page 1 of 18
Region 6 - Enforcement & Compliance Assurance Division
INSPECTION REPORT
Inspection Date(s): Media Program: Regulatory Program(s)
08/01/2022 Air SIP, Title V
Company Name: Facility Name: Facility Physical Location: (city, state, zip code) County/Parish: Facility Coordinates (Entrance): Facility Phone Number Facility Contact:
Enterprise Products Operating, LLC
Norco Fractionation Plant
15608 HWY 61
Norco, LA 70079
St. Charles Parish
30.014013, -90.404699
504-465-7246
Allyson Cronin
Operations Supervisor
akcronin@eprod.com
FRS Number: Identification/Permit Number: Media Identifier Number: NAICS: SIC:
110015604283 LDEQ Agency Interest Number 51546 AFS # 22-089-00078 211112 - Natural Gas Liquid Extraction 1321 - Natural Gas Liquids
Personnel participating in inspection:
James Haynes
EPA Region 6, Air Toxics Enforcement
Colleen McCarthy
EPA Region 6, Air Toxics Enforcement
Jon Morris
Providence Photonics
Michael Morris
Providence Photonics
Allyson Cronin
Enterprise Products Operating
Damian Watt
Enterprise Products Operating
Physical Scientist Life Scientist EPA Contractor EPA Contractor Operations Supervisor Environmental
EPA Lead Inspector Signature/Date
JAMES HAYNES Date: 2023.01.27 13:14:01 -06'00' Digitally signed by JAMES HAYNES
James Haynes
Date
Supervisor Signature/Date
JAMES LEATHERS Date: 2023.01.27 14:25:25 -06'00' Digitally signed by JAMES LEATHERS
James Leathers
Date
6ENFORM-019-R8.2 (02/12/2020)
1
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Enterprise Products Operating, LLC/Norco Fractionation Plant Inspection Date 08/01/2022
Section I - INTRODUCTION
PURPOSE OF THE INSPECTION
I, James Haynes, U.S. Environmental Protection Agency ("EPA") Region 6 inspector, arrived at the Enterprise Products Operating, LLC ("Enterprise") Norco Fractionation Plant in Norco, LA on August 1, 2022, to conduct an unannounced Clean Air Act ("CAA") inspection. I arrived with Ms. Colleen McCarthy, EPA Region 6 inspector and two EPA contractors with Providence Photonics - Mr. Jon Morris and Mr. Michael Morris. We met with Enterprise representative Ms. Allyson Cronin, Operations Supervisor, and I presented my inspector credentials to Ms. Cronin and notified her of my intent to conduct a CAA Partial Compliance Evaluation ("PCE"). EPA contracted Providence Photonics to conduct flare observations using the Video Imaging Spectral Radiometry ("VISR") method. VISR uses a cooled, multi-spectral midwave infrared imager to measure relative concentrations of combustion gases to calculate a flare's combustion efficiency ("CE").
FACILITY DESCRIPTION
The Norco Fractionation Plant produces ethane, propane, isobutane, n-butane, and natural gasoline by separating and recovering components from natural gas liquids from nearby gas processing plants.
Section II - OBSERVATIONS
After entry, Ms. Cronin provided me with an overview of the site operations and current conditions. Ms. Cronin noted that the flare is equipped with two air blowers operating at 100%. Providence Photonics set up the imaging device outside the process area and began collecting CE data at the elevated flare at 10:30 AM. Additionally, Ms. McCarthy and I entered the process area and used a FLIR Optical Gas Imaging Model GF320 and a digital camera.
After leaving the process area, Ms. Cronin notified the control room to reduce both blowers to 75% while we continued to record CE data. Providence Photonics stopped collecting data at 12:03 PM. See Appendix 1. I conducted a brief closing conference with Enterprise, and we exited the facility.
Section III - AREAS OF CONCERN
During the closing conference, I noted that EPA and Providence Photonics observed a decrease in the variability of the CE after the blower adjustments. In general, achieving 96.5% CE correlates to approximately 98% destruction efficiency and good flare performance.
Section IV - FOLLOW UP
After EPA exited the facility, Enterprise provided additional information on August 19, 2022.
Section V - LIST OF APPENDICES
Appendix 1 - VISR Flare Measurement Report
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Enterprise Products Operating, LLC/Norco Fractionation Plant Inspection Date 08/01/2022
Appendix 1 VISR Flare Measurement Report
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Project No. 0000-000 | Project Name
VISR Flare Measurement Report Facility: Enterprise Gas Processing
Norco Fractionation Plant
15608 Hwy 61 Norco, LA 70079 St. Charles Parish, Louisiana
Prepared for US Environmental Protection Agency
Region 6 1201 Elm Street, Suite 500
Dallas, TX 75270
PROJECT NO. 0010-004-001
PREPARED BY Providence Photonics, LLC | 1201 Main Street, Baton Rouge, LA 70802
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Project No. 0010-004-001 VISR Flare Inspection Report
Table of Contents
INTRODUCTION........................................................................................................................................... 2 BACKGROUND ............................................................................................................................................. 2 SUMMARY OF INSPECTION........................................................................................................................ 3 OBSERVATIONS ........................................................................................................................................... 4
Field Conditions ...............................................................................................................................................................................4 Process Conditions .........................................................................................................................................................................4 ELECTRONIC DATA GENERATED FROM THE TEST.................................................................................... 5 REFERENCES ................................................................................................................................................. 5 APPENDIX A: RESULTS ................................................................................................................................ 7 APPENDIX B: VALIDATION OF THE VISR METHOD .................................................................................. 8
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Project No. 0010-004-001 | VISR Flare Inspection Report
Introduction
Through its contract 68HERC21D0007/Task Order 68HERC21F0185 with Eastern Research Group, Inc. (ERG), EPA Office of Enforcement and Compliance (OECA) and Region 6 retained Providence Photonics, LLC (Providence) to assist the inspection of the Enterprise Fractionation Plant (Enterprise) located at 15608 Highway 61, Norco Louisiana, 70079. Providence measured the combustion efficiency (CE) and other performance metrics of the Enterprise flare using the Video Imaging Spectral Radiometry (VISR) method.
Background
The VISR method utilizes a multi-spectral mid-wave infrared imager to remotely and continuously measure relative concentrations of combustion gases. Based on these relative concentrations, flare CE is calculated. The VISR method provides continuous measurement of the following five flare performance metrics at 1-second data rate.
1. Combustion Efficiency (0 to 100%): Combustion efficiency (CE) is a measure of the relative concentration of hydrocarbon vs. carbon dioxide in the post combustion gas plume. If there is no hydrocarbon present in the post combustion gas plume, then CE is 100%.
2. Smoke Index (0 to 10): Smoke index (SI) is a unit-less number which indicates the degree of visible emissions within the combustion envelope. A SI of 0 means no visible emissions are present while a SI of 10 means the flare has heavy black smoke. While SI only represents the degree of visible emissions within the combustion envelope, it is generally correlated to opacity and a SI above 3 generally indicates that some visible emissions are likely present outside of the combustion envelope.
3. Flame Footprint (m2): Flame footprint (FF) is a measure of the flame size in square meters. It is not necessarily correlated to the visible flame size as the FF is determined by the Infrared radiance, not the visible flame. Note that the orientation of the flame will impact the FF as the depth of the flame will change with viewing angle.
4. Fractional Heat Release (MMBtu/Hr): Fractional Heat Release (FH) is a measure of the heat released from flare combustion in the spectral bands monitored by the Mantis flare monitor. Although it is not a measure of the total heat release across the entire energy spectrum, FH is expected to be correlated to the total heat release.
5. Flame Stability (0 to 100%): Flame stability (FS) is a measure of the change in radiance measured by the Mantis flare monitor in a 1-second interval. A FS of 100% indicates a flame that has a constant radiance. A low FS value (generally lower than 80%) indicates a flame with significant radiance fluctuation within 1 second interval, suggesting a less stable flame. Variability on a longer time scale will not be described by the flame stability metric.
Appendix B provides additional information on the accuracy and precision of the VISR method. More information about the VISR method and its validation is provided at https://www.providencephotonics.com/flare-monitoring.
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Project No. 0010-004-001 | VISR Flare Inspection Report
Summary of Inspection
Inspection Date:
August 1st, 2022
Personnel:
James Haynes (EPA Region 6) Colleen McCarthy (EPA Region 6)
Jon Morris (Providence) Michael Morris (Providence)
Facility:
Enterprise Gas Processing LLC - Norco Fractionation Plant 15608 Hwy 61, Norco, LA 70079
Results:
Table 1 below provides a summary of the VISR results. Complete results can be found in Appendix A.
Date 8/1/2022 8/1/2022 8/1/2022
Start Time (Local)
10:30 AM 11:31 AM 11:35 AM
End Time (Local)
11:31 AM 11:35 AM 12:03 PM
Process Condition Both blowers at max One blower reduced to 75% of max Both blowers reduced to 75% of max
Distance (m)
201 201 201
Temp (C)
30 30 30
RH (%)
80 80 80
Avg Wind Speed (mph)
2 - 4 2 - 4 2 - 4
CE Avg (%)
97.43 98.18 98.67
SI Avg 0.46 0.53 0.58
FF Avg FH Avg
(m2) (MMBTU/HR)
8.0
0.08
8.7
0.10
11.3
0.15
FS Avg (%)
91 92 94
Table 1: Summary VISR Results.
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Project No. 0010-004-001 | VISR Flare Inspection Report
Observations
The following sections describe field observations and comparisons derived from the dataset.
Field Conditions There was nothing notable about the field conditions. The VISR instrument was set up 201 meters from the flare tip, well within the method limits. The weather conditions were 30C with light winds (2-4 mph) and a clear sky.
Process Conditions The Enterprise Norco flare is air assisted and equipped with two air blowers. When the inspection began, both blowers were operating at 100%. At 11:31 AM, the facility reduced the blower setting on one of the two blowers from 100% to 75%. The result was a measurable increase in Combustion Efficiency (from 97.4% to 98.2%). At 11:35 AM, the second blower was reduced to 75% as well. Again, the result was a slight increase in Combustion Efficiency (from 98.2% to 98.7%). Overall, the adjustments to the blower settings improved the Combustion Efficiency by about 1.3%, which translated to a 50% reduction in terms of incomplete combustion [incomplete combustion dropped from 2.6% (=100%-97.4%) to 1.3% (=100%98.7%)] and a significant reduction in emission rate.
Figure 1 shows a time series plot of Combustion Efficiency and Fractional Heat Release. The general trend of improving Combustion Efficiency during the inspection (as blower settings were reduced) can be observed in the time series plot.
Figure 1: Combustion Efficiency and Fractional Heat Release for Enterprise Norco flare on 8/1/2022.
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Project No. 0010-004-001 | VISR Flare Inspection Report
Figure 2 below shows Combustion Efficiency and Smoke Index during the inspection. The Smoke Index showed an increasing trend as the blower settings were reduced. A Smoke Index less than 3 is generally associated with smokeless flare operations. In this case, the 30 second average Smoke Index did not exceed 1 and no visible emissions were observed from the flare.
Figure 2: Combustion Efficiency and Smoke Index for Enterprise Norco flare on 8/1/2022.
Electronic Data Generated from the Test
The following electronic data are submitted to the US EPA Region 6 as part of this report: A Microsoft Excel file containing second-by-second results from the VISR instrument and averages for each measurement period. FLIR video recording of the flare during the inspection.
References
1. Yousheng Zeng, Jon Morris & Mark Dombrowski (2015) Validation of a new method for measuring and continuously monitoring the efficiency of industrial flares, Journal of the Air & Waste Management Association, 66:1, 7686, DOI: 10.1080/10962247.2015.1114045
2. Yousheng Zeng, Jon Morris. (2019, April 2nd). Precision and Accuracy of the VISR Method for Flare Monitoring. Air Quality Measurement Methods and Technology, Durham, North Carolina, United States.
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Appendix A: Results
Date 8/1/2022 8/1/2022 8/1/2022
Date/Time
Start Time End Time
(CST)
(CST)
10:30 AM 11:31 AM
11:31 AM 11:35 AM
11:35 AM 12:03 PM
Site Enterprise Norco Enterprise Norco Enterprise Norco
Table 2: Complete VISR Results.
Site Description
Description Both blowers at max One blower reduced to 75% of max Both blowers reduced to 75% of max
Distance (m)
201 201 201
Conditions
Temp RH Wind Speed (C) (%) (mph)
30 80 2 - 4 30 80 2 - 4 30 80 2 - 4
Efficiency (%)
CE
CE
CE
Avg Min Max
97.43 86.21 99.90
98.18 96.50 99.41
98.67 95.14 99.99
SD 1.27 0.64 0.51
Smoke Index (0-10)
Avg 0.46 0.53 0.58
Min 0.15 0.31 0.27
Max 1.41 0.92 1.65
SD 0.13 0.11 0.15
Flare Footprint (m2) Fractional Heat (MMBTU/HR)
Avg 8.0 8.7 11.3
Min 2.4 6.4 5.7
Max 14.2 12.3 15.9
SD 1.9 1.1 1.6
Avg 0.083 0.096 0.147
Min 0.013 0.065 0.045
Max 0.224 0.157 0.277
SD 0.030 0.016 0.030
Flame Stability (%)
Avg 91.4 92.0 93.9
Min 52.7 75.2 18.0
Max 99.9 99.9 100.0
SD 5.1 3.9 3.5
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Appendix B: Validation of the VISR method
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Precision and Accuracy of the VISR Method for Flare Monitoring
Extended Abstract: ME92 Presented at the conference: Air Quality Measurement Methods and Technology April 2-4, 2019 Durham, NC
Jon Morris, Yousheng Zeng, and Srikanth Mutyala Providence Photonics, Baton Rouge, Louisiana
Introduction
Industrial flares represent a large category of air emission sources for Volatile Organic Compounds (VOC), air toxics, and greenhouse gases (GHG)1-4. Depending on their combustion efficiency (CE), the emissions of these air pollutants can be significantly different. Despite the large contribution of flares to air emission inventories, flares are the only source category for which no EPA test or monitoring methods can be applied to directly measure their efficiency or emission rates. As a result, flare emissions in air emission inventories may carry significant uncertainties.
A method based on Video Imaging Spectral Radiometry (VISR) has been developed for testing or continuously monitoring combustion efficiency (CE) of industrial flares5. To validate the VISR method, tests were conducted at flare test facilities of Zeeco, Inc. (Zeeco) and John Zink Hamworthy Combustion (John Zink), both located in Tulsa, Oklahoma, in September and October 2016, respectively. The test at Zeeco included both an air assisted flare and a steam assisted flare. Twenty-eight flare conditions were tested, 14 for the air flare and 14 for the steam flare. This test is referred to as the "Zeeco Test" in this paper.
The test at John Zink was part of a program sponsored and organized by the Petroleum Environmental Research Forum (PERF), an industry consortium. PERF project 2014-10 Direct Monitoring of Flare Combustion Efficiency was created and funded by participating PERF companies to provide a test platform for various developers/vendors of flare remote sensing technologies (Invitees) to participate in a blind test to evaluate the effectiveness of each technology. The blind test was administered by John Zink. Testing began on October 17th, 2016 and continued for 10 days, concluding on October 27th, 2016. The flare tip used was the John Zink model EEF-QSC-36, which was the same flare tip used during the 2010 TCEQ Flare Study4. A test protocol was developed which identified a series of test conditions to evaluate various factors
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that could affect flare CE measurement. Only limited logistical and environmental factors were shared with the Invitees (i.e., distance from the flare, view angle with respect to flame orientation due to wind, sun in/out of the field of view, daytime/nighttime testing). Information regarding flare operations such as the type of fuel gas used, firing rates, steam rates or any other flare operating parameters was concealed from Invitees. A total of 45 test points was evaluated over the 10 days of testing. Extractive sampling was performed on each test point as the control method for flare CE measurement. The results of the extractive sampling were not provided to Invitees until Invitees submitted their won results based on their respective measurement technology. This test is referred to as the "PERF Test" in this paper.
In this paper, the precision and accuracy of the VISR method are evaluated based on the test campaigns described above.
Methods and experimental setup
The VISR flare monitor is a remote monitoring device that can be positioned at any distance as long as the flare to be monitored is in the line of sight and there are a sufficient number of pixels of the flare flame image in the VISR monitor. The distances from flare to the VISR monitor in the experiments reported here were in the range of 174 feet to 650 feet. To evaluate the performance of the VISR method, an extractive sampling system was used as a reference method. A sample extraction apparatus was suspended by a crane over the flare plume to extract combustion product gases. The sample was transported through a heated sampling line to a sample manifold in a testing trailer. The sample manifold was connected to analyzers for oxygen (O2), carbon dioxide (CO2), carbon monoxide (CO), and hydrocarbon (HC). The methods for measuring O2, CO2, CO, and HC were EPA Method 3A, 3A, 10, and 25A, respectively. The level of O2 was used to confirm that the sampling probe was in the flare plume. The concentrations of CO2, CO, and HC were used to calculate flare CE per method used in the 2010 TCEQ flare study3.
These test campaigns covered a wide range of process conditions: two steam flares and one air flare; multiple vent gas compositions (natural gas, propane, propylene, hydrogen, in pure form or mixed with nitrogen; vent gas flow range from 10 lb/hr to 10,000 lb/hr; various steam and air assist levels resulting in combustion zone net heating value (NHVcz) in a range of 120 to 1,250 Btu/scf for the steam flares and net heating value dilution parameter (NHVdil) in a range of 6.7 to 244 Btu/ft2 for the air flare.
The test campaigns also covered a wide range of environmental conditions: distance ranging from 174 ft. to 650 ft.; different wind speed and direction (crosswind, wind oriented towards VISR device, and wind oriented away from VISR device); daytime vs. nighttime; various sky conditions (blue sky, cloudy, moving clouds); the Sun in or out of field of view; rain, and fog.
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Results and Discussions
Precision
Precision is a measure of how the results of multiple measurements by the same method scatter while the target of the measurement holds steady. This is difficult to assess for flare measurements because even when the flare operating conditions are held steady (as they were in each test point of the PERF Test), the flare CE may change due to changes in environmental conditions. Analyte spiking or quadruplet sampling described in EPA Method 301 would help to isolate the measurement method precision from the fluctuation of the target itself6. However, these methods are not feasible for flare measurement. Nevertheless, the measurement precision can still be evaluated using the data from the PERF test. For each PERF test condition, 4 segments of measurement were made by the extractive method and 3 segments of measurement were made by VISR while the flare operating conditions were held constant (although flare CE did fluctuate due to changes in environmental conditions). The standard deviation (SD) and relative standard deviation (RSD) can be calculated based on these replicate measurements. Table 1 is a summary of the SD and RSD for both the VISR method and the extractive method used in the PERF Test. As shown in Table 1, the RSD for the VISR method is in a range of 0.07% to 1.98% with an average of 0.62%. The variation of the VISR method appears to be slightly better than the extractive method from the perspective of both the average and the range of the RSD values, suggesting that the precision of VISR is at least as good as the extractive method. Note that in both cases, the variation due to changing environmental conditions is included in the RSD as there is no practical method to separate it. Despite the inclusion of environmental changes, the RSD is more than an order of magnitude smaller than 20% as required in EPA Method 301 (Section 9.0)6. If a more stringent criteria is used in which the 20% limit on RSD is applied to the most relevant range of 90-100 % CE measurement (i.e., in the span of 10 % CE measurement), the criteria would be SD < 2 % CE (20% of 10% = 2 % CE). As shown in Table 1, the highest SD is 1.84 measured as % CE, which is lower than the SD of 2 % CE measurement and therefore satisfies the more stringent criteria.
Table 1. Relative Standard Deviation (RSD) of VISR and extractive method per PERF Test
Method
VISR Extractive
CE Avg. 96.47 96.41
CE Range 80.61-99.91 83.50-100.00
SD Avg. 0.59 0.83
SD Range 0.07-1.84 0.00-2.61
RSD Avg. 0.62% 0.88%
RSD Range 0.07-1.98% 0.00-2.72%
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The Zeeco Test did not include multiple replicated measurements under each test condition. Therefore, a precision analysis is not performed on that data.
Accuracy
The accuracy of the VISR method is evaluated based on the Zeeco Test and PERF Test. In these two tests, the flare CE was measured by both the VISR method and the extractive method. The extractive method was used as the control (reference) method. Strictly speaking, what can be assessed is the agreement between the two methods, not the accuracy of either method because the true flare CE is unknown. The agreement between the two methods can be evaluated using a statistical method. One such method is to use t-test on the differences between the paired CE measurements by VISR and extractive methods. This method is the same as the method used in EPA Method 301 to determine if there is a difference caused by different sample storage time6 (it should be noted that the methods for bias described in Method 301 are not directly applicable because they are specifically designed for analyte/isotopic spiking or quadruplet sampling systems, which are not feasible for flare measurement). The value of the t-statistic is calculated using the following equation.
= ||
Where dm and SDd are the mean and the standard deviation of the difference of the paired samples (VISR and extractive sample), and n is the total number of samples. The resulted t-statistic value is compared to the critical value of the t-statistic with a 95 percent confidence level and n-1 degree of freedom. If the resulted t-statistic value is less than the critical value, the difference between the VISR method and the extractive method is not statistically significant, i.e., the two methods are statistically the same. The results of the t-statistical analysis for both Zeeco and PERF tests are summarized in Table 2. The number of samples (tests) in Table 2 is less than the number of tests actually conducted because some tests were designed for other purposes (e.g., smoke test) and they are not included in the evaluation of the agreement between VISR and extractive methods.
Table 2. t-Test to determine if the VISR method is different from the extractive method
No. of Samples, n Mean Difference, dm (% CE)
Zeeco Test (Steam Flare)
11
0.30
Zeeco Test (Air Flare)
9
-0.21
PERF Test
42 0.07
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Standard Deviation, SDd (% CE) t-Statistic Value Degree of Freedom t_95 Critical Value Statistically Different?
Project No. 0010-004-001 | VISR Flare Inspection Report
1.32 0.756
10 2.228
No
0.65 0.967
8 2.306
No
1.69 0.254
41 2.020
No
As demonstrated in Table 2, statistically there is no difference between the flare CE measured by the VISR method and by the extractive method. The agreement between the two measurement methods can also be illustrated in Figure 1 using the results from the PERF Test.
Figure 1. Flare CE measured by VISR method and extractive method - PERF Test results
Conclusion
Industrial flares can now be measured or continuously monitored by the VISR method for their performance, i.e., combustion efficiency (CE). The VISR method is a remote sensing method and can be deployed easily and practically. The VISR method transforms flare testing/monitoring from most difficult task (impossible in many cases) to a task that is easier than most conventional air emission testing methods. With the significant potential benefits that the VISR method can bring, it is important to characterize and understand the precision and accuracy of this method.
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Through a large number of tests under various process and environmental conditions, a high precision and accuracy have been demonstrated for the VISR method. The relative standard deviation (RSD) is in the range of 0.07-1.98% with an average RSD of 0.62% for flare CE in the range from 80 to 100%. The average RSD of 0.62% is more than an order of magnitude smaller than the minimum precision target of 20% RSD set in EPA Method 301. The highest SD is only 1.84 measured as % CE.
The flare CE measured by the VISR method is in excellent agreement with the flare CE measured by the extractive method. The mean difference between the two methods is in the range of -0.21 to 0.30 measured in % CE. The t-statistic value in each of the three test groups are well below its corresponding t-test critical value, passing the t-test with a substantial margin. Keep in mind that the extractive method is suitable only in research. It is virtually impossible to deploy the extractive method to elevated flares at industrial production facilities. Having a method that can be easily deployed to industrial sites and produce highly time-resolved and accurate flare measurement results is a significant advancement.
REFERENCES
1. Emam, E.A., Gas Flaring in Industry: An Overview, Petroleum & Coal, 57(5) 532-555, 2015. http://large.stanford.edu/courses/2016/ph240/miller1/docs/emam.pdf (accessed January 23, 2019).
2. USEPA, "Fact Sheet, Proposed Petroleum Refinery Sector Risk and Technology Review and New Source Performance Standards", 2015. http://www.epa.gov/airtoxics/petrefine/20140515factsheet.pdf (accessed on March 24, 2015).
3. ENVIRON, Cost Analysis of HRVOC Controls on Polymer Plants and Flares, Report prepared for Texas Commission on Environmental Quality, Project 2008-104, Work Order 582-07-84005-FY0812, 2008. http://www.tceq.state.tx.us/assets/public/implementation/air/rules/Flare/HRVOC_Cost_Analysis_Rep ort.pdf (accessed March 23, 2015).
4. Allen, D.T. and V.M. Torres, TCEQ 2010 Flare Study Final Report, prepared for TCEQ. PGA No. 582-8-862-45-FY09-04 with supplemental support from TCEQ Grant No. 582-10-94300, 2011. http://www.tceq.texas.gov/assets/public/implementation/air/rules/Flare/2010flarestudy/2010-flarestudy-final-report.pdf (accessed March 23, 2015).
5. Zeng, Y, J. Morris, and M. Dombrowski, Validation of a New Method for Measuring and Continuously Monitoring the Efficiency of Industrial Flares, J. Air & Waste Manage. Assoc. 66:7686 (2016).
6. U.S. EPA, Code of Federal Regulations, Title 40, Part 63, Appendix A, Method 301, 2018.
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