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Standards Certification Education & Training Publishing Conferences & Exhibits Development of Emission Factors from API 622/624 Test Data Buzz Harris and Bronson Pate Sage Environmental Consulting 15 th LDAR Symposium May 19-21, 2015 New Orleans, LA
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2 Presenter Information Buzz Harris holds a BS in Chemical Engineering with 45 years experience and still learning Bronson Pate holds a degree in Engineering with 8 years of full time experience plus 3 years of internships in LDAR during university studies
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3 Overview Low Emission (Low E) Technology Introduction Primary US tests for Low E packing and valves use methane and include Method 21 type readings Tests are based on accelerated wear that should be representative of 5 years or more of field operations EPA is requiring Low E in new Consent Decrees and encouraging voluntary application Emission Factors (EF) and control efficiencies can be developed from the test readings, which, if approved, would provide more incentive to use Low E in any new construction Conclusions
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Low E Technology There have always been packings and valves that were more or less likely to leak Only recently, however, have we had guarantees, warranties, and, most importantly, test data to prove manufacturer’s claims of low emissions Based on hard data, EPA has begun to require Low E in Consent Decrees written over the last 4 to 5 years Several companies had begun their own Low E testing and implementation voluntarily before that The use of Low E is gradually being recognized as cost effective and just good business 4
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Fugitive Emissions Testing A number of valve and packing tests have been developed: ISO 15848-1 is an EU and British standard that allows testing by either helium or methane, with most test data to date done with helium API 622 is a packing test using methane API 624 is a valve test using methane ChevronTexaco test procedure is similar to API 622, but it tests packing in a valve and includes more wear cycles Shell also has its own packing test The API test procedures have more industry wide applicability and focus on methane testing 5
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API 622 and 624 Details 6 Comparison of Service Parameters: API 622 and API 624 Standard identificationAPI STD 622 API STD 624 Title and edition Type Testing of Process Valve Packing for Fugitive Emissions, Second Edition Type Testing of Rising Stem Valves Equipped with Graphite Packing for Fugitive Emissions, First Edition Date Standard by the American Petroleum Institute, 10/01/2011 Standard by the American Petroleum Institute, 02/01/2014 Pass Criteria500 ppmv maximum after one adjustment100 ppmv maximum EquipmentSpecified fixture simulating a valveValve being qualified Packing adjustmentOne allowed1None allowed MediaMethane 97% minimum purity Temperature500°F (260°C) Pressure600 psig (41.4bar-g) Number of valve stem actuations1510310 Number of thermal cycles53 Leak measurement methodMethod 21 Leak measurement detailsDone with stem in static stateDone with stem in static and dynamic states Leak measurement frequencyEvery 50 actuations of the stem Prepared by and used with permission of Garlock
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API 622 Test Data 7
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PPM Readings in API 622 and 624 Probe split in two to simultaneously check both stem and packing Tin foil used as a partial shroud to try to collect leakage from any point around the stem and packing Record ppmv data over a minute and report the average and maximum with no background correction Some report both static and dynamic (stem moving) readings This paper uses the maximum readings recorded in either static or dynamic modes This should be conservatively higher than traditional M21 readings 8
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Mass Emissions from ppm For petroleum industry: –Default Zero EF (reading zero) = 0.0000078 kg/hr/source –Correlation equation = 2.29*10^-6*SV^0.746 kg/hr/source For chemical industry: –Default Zero EF (reading zero) = 0.00000066 kg/hr/source – Correlation equation = 1.87*10^-6*SV^0.873 kg/hr/source No need for Pegged EF in Low E testing! These emission estimates are for the instant the measurement occurs Still need to estimate emissions over time 9
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Accelerated Wear Time API 622 includes 1510 mechanical wear cycles and 5 thermal stress cycles API 624 includes 310 mechanical wear cycles and 3 thermal stress cycles, but also requires packing to have passed API 622 before 624 testing The tests take place over 3 to 6 days, but represent a much longer period because of the accelerated use The equivalent process life may vary with: –Continuous vs. batch processes –Process application of the valve (manual isolation, drain, sample, motor operated, control, etc. valve) –Other factors too process specific for consideration here 10
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Continuous Process – Cycles to Time 11 Accelerated Wear Cycles to Operating Time Continuous ProcessesFrequency per year% of TotalWeighted Frequency Valve ApplicationLow EndHigh EndValvesLow EndHigh End Manually operated block isolation valves11078%0.787.8 Block valves isolating pumps5242%0.10.48 Drain valves121205%0.66 Sample valves527952%1.0415.9 Motor operated valves15010002%320 Process control valves500500011%55550 Totals7206949100%60.52600.18 Average Annual Operation Cycles 330.35 Years of Operation for 1510 Operating Cycles 4.57
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Batch Process – Cycles to Time 12 Accelerated Wear Cycles to Operating Time Batch ProcessesFrequency per year% of TotalWeighted Frequency Valve ApplicationLow EndHigh EndValvesLow EndHigh End Manually operated block isolation valves1236575%9273.75 Block valves isolating pumps243652%0.487.3 Drain valves123655%0.618.25 Sample valves527952%1.0415.9 Motor operated valves15010005%7.550 Process control valves500500011%55550 Totals7507890100%73.62915.2 Average Annual Operation Cycles 494.41 Years of Operation for 1510 Operating Cycles 3.05
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Continuous Process – Thermal Cycles to Time 13 Thermal Cycles to Operating Time Continuous Processes:ScheduledUnsheduledTotal Run Lengths Between T/A, yrsShutdowns/yr 50.200.50.70 40.250.40.65 30.330.30.63 20.500.20.70 11.000.11.10 Average 0.76 Years Operation for 5 thermal cycles 6.61
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Batch Process – Thermal Cycles to Time 14 Thermal Cycles to Operating Time Batch Processes:ScheduledUnsheduledTotal Campaign Run Lengths, daysShutdowns/yr 3012.170.0512.22 2018.250.0418.29 1036.500.0336.53 573.000.0273.02 1365.000.01365.01 Average 101.01 Years Operation for 5 thermal cycles 0.05
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Summary – Accelerated Wear Time 1510 mechanical wear cycles represent 3.1 to 4.6 years of operating time for batch/continuous process units 5 thermal cycles represent 0.1 to 6.6 years of operating time for batch/continuous process units EPA defines Low E as <100 ppm operations for 5 years, and accepts API 622 data as satisfying that definition –The thermal cycles in API 622 falls far short of the potential thermal cycles in 5 years for a batch process, but –API 622 accelerated wear cycles average to around 5 years equivalent operation for continuous operating units and mechanical wear for batch units This paper, therefore, assumes that the API 622/624 readings are spread evenly over a 5 year period 15
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API 622 Emissions Over Time Example 1510 cycles with a reading every 50 cycles (including beginning and end readings) results in 42 readings 42 readings spread evenly over 5 years would be one reading every 45.6 days (roughly every 6 weeks) Default zero and correlation equations for petroleum and SOCMI are used to calculate instantaneous emission estimates Emissions from the previous to current readings are averaged over the 45.6 days between readings Emissions are summed over the 42 total readings and divided by the time in years to create an average emission factor in kg/yr/source Emission Factor for static and dynamic readings are averaged 16
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API 624 Emissions Over Time Example 310 cycles with a reading every 50 cycles (including beginning and end readings) results in 14 readings 14 readings spread evenly over 5 years would be one reading every 140.4 days (roughly semi-annual) Default zero and correlation equations for petroleum and SOCMI are used to calculate instantaneous emission estimates Emissions from the previous to current readings are averaged over the 140.4 days between readings Emissions are summed over the 14 total readings and divided by the time in years to create an average emission factor in kg/yr/source Emission Factor for static and dynamic readings are averaged 17
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Emission Factors Summary 18 API 622 and 624 tests reports were provided by and thanks go to: Ron Walters of Teadit North America Todd Haberkost of Ladish Valves Jim Drago of Garlock Scott Boyson and Rodney Roth of A.W. Chesterton Company Josh Erd of Nippon Pillar Corporation of America
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Low E Emission Factor Considerations All of these emission factors calculated from low emission packing and valves are near the default zero emission factor for valves –One approach to encourage voluntary use of Low E would be to allow use of the default zero factor to predict emissions for permitting –Another approach would be to allow an average emission factor (or control efficiency) for Low E valves and packing to date to be used to predict emissions for permitting –Another approach would be to require applicants to include calculations of an emission factor for the specific Low E equipment they will use 19
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Control Efficiency Approach In lieu of developing emission factors for Low E, it would also be possible to develop a control efficiency for application of Low E that could be applied to the normal average emission factor The following table shows control efficiency estimates calculated as: CE%=(1-(Average EF/Low E EF))X100 Each Average EF above is for valves in a specific service category in a specific industry Each Low E EF above is for valves in a specific industry, but all testing is done on Gas/Vapor service (methane, 600 psi) 20
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Low E Control Efficiency 21 Low E Emission Factors are the average of all the API 622/624 tests using either petroleum or chemical correlations/default zero emission factors.
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Conclusions The measurements done in API 622/624 testing give methane ppmv data that can be used to estimate emissions API 622/624 are accelerated wear tests that appear to represent a five year period for the average valve (with the exception of thermal cycles on a batch process) Emission factors (EFs) developed for API 622/624 data range in value from 4.6E-6 up to 1.8E-5, falling about one order of magnitude higher than the default zero EFs (6.6E-7 up to 7.8E-6) Control efficiency numbers for the Low E EFs compared to EPA Protocol Average EFs range from 97.3 to 99.9% 22
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Conclusions These Low E EFs and control efficiencies could be used for permitting, where actual components that can be monitored do not exist yet EPA should also consider allowing use of Low E EFs for non-monitored valves (such as HL service, UTM, etc.) Neither EPA nor the states currently accept these Low E EFs and control efficiencies for permitting We ask that EPA review these calculations and/or replicate their own approach to similar calculations EPA-sanctioned Low E EFs and/or control efficiencies would add another incentive for every new facility or modification to be done with Low E technology 23
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