1、STDnAPIIPETRO PUBL 4b45-ENGL 1997 0732290 05b3390 b97 a31 American Petroleum Institute METHANE AND CARBON DIOXIDE EMISSION ESTIMATES FROM U.S. PETROLEUM SOURCES Health and Environmental Sciences Department Publication Number 4645 January 1997 STD.API/PETRO PUBL LIb45-ENGL 1797 0732270 (35b3391 525 M
2、ethane and Carbon Dioxide Emission Estimates From US. Petroleum Sources Health and Environmental Sciences Department API PUBLICATION NUMBER 4645 PREPARED UNDER CONTRACT BY: MATHEW R. HARRISON, P.E. THERESA M. SHIRES RADIAN INTERNATIONAL LLC 8501 N. MOPAC BLVD. AUSTIN, TEXAS 7859 JANUARY 1997 America
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6、 Copyright O 1997 American Petroleum Institute . 111 TABLE OF CONTENTS Section Paae EXECUTIVE SUMMARY . ES-I RESULTS . e5-2 SENSITIVITY ANALYSIS . e54 CONCLUSIONS e5-5 3 1 2 INTRODUCTION . 1-1 . 1-1 PETROLEUM INDUSTRY BOUNDARY DEFINITION COMPARISON OF METHODOLOGIES . 2.1 STANDARD APPROACH . 2.2 LITE
7、RATURE REVIEW . 2-2 KEY ELEMENT COMPARISONRANKING 2-3 Boundaries . 2-3 Detail Level 2-4 Data Quality . 2.15 Representativeness . 2-18 Comprehensiveness . 2-19 Practicality 2.25 CONCLUS IONS . 2.26 i 3 4 1990 EMISSION ESTIMATE 3-1 METHANE EMISSIONS 3-1 Production . 3-6 Crude Transportation . 3-7 Refi
8、ning . 3-8 ProductTranspo rt 3-8 Production . 3-9 Crude Transportation 3-10 Refining 3-10 Product Transportation . 3-11 CARBON DIOXIDE EMISSIONS 3-9 METHODOLOGY FOR PROJECTIONS TO 2000 4.1 METHODOLOGY FOR METHANE ACTIVITY FACTOR PROJECTIONS . 4.1 Production . 4-1 Crude Transportation . 4-2 Refining
9、. 4-3 Product Transportation 4-3 Mass Balance . 4-3 TABLE OF CONTENTS (Continued) Section Paae METHODOLOGY FOR CO. ACTIVITY FACTOR PROJECTIONS 4.5 Production . 4-5 Crude Transportation . 4-5 Refining . 4-6 Product Transportation 4.6 METHODOLOGY FOR EMISSION FACTOR PROJECTIONS . 4.7 Oil and Gas (O Es
10、timation of year 1990 industry emissions using the Intergovernmental Panel on Climate Change (IPCC) methodology to the extent possible as well as data from other sources as necessary; Selection of a methodology for projecting emissions to the year 2000; and Estimation of emissions for the year 2000.
11、 Tasks 1 and 2 were based upon reviews of existing greenhouse gas inventory literature, and Tasks 3 and 4 were based upon review and use of available published data showing activity and emission projections. Emission estimates for a given time period are calculated by multiplying an emission factor
12、(e.g., units of mass emissions per volume throughput) by an activity rate (e.g., units of volume throughput per time period). API previously estimated global emissions of carbon dioxide and methane from petroleum sources in reports issued in 1991 -1 992. This report updates those estimates for the e
13、xploration and production, crude transportation, refining, and product transportation segments of the United States petroleum industry. The approach used ES-I I STD.API/PETRO PUBL 4b45-ENGL 1797 0732290 05b3377 81b in this study represents the best available approach for the level of emissions and a
14、ctivity data that is publicly available. This approach is preferable to the United Nations IPCC methodology for calculating national estimates of greenhouse gas emissions for two reasons: 1) 2) It is specific to the petroleum industry; and It includes some source categories which are omitted in the
15、IPCC methodology. RESULTS Existing greenhouse gas emissions literature was reviewed, examining the following key parameters: boundaries, detail level, representativeness, comprehensiveness, data quality, and practicality. None of the existing studies reviewed were found to be ideal for estimating em
16、ission rates for the U.S. petroleum industry, but a best estimate approach was developed using the IPCC methodology as a basis with supplemental estimates from the other studies examined. Methods for estimating (year 1990) and projecting (year 2000) activity factors for the petroleum industry were d
17、eveloped based on the literature. Projected changes to emission factors resulting from implementation of proposed regulations as well as energy efficiency improvements were also identified. Table ES-1 presents the estimated and projected methane and CO, emissions from the U.S. petroleum industry. Th
18、e total year I990 emissions of CO2 from petroleum production through product transport are 284 million tons, which compares reasonably well with the estimate in the previous API report of 300 million tons. The differences can be attributed to updated activity factors for the production and transport
19、ation industry segments, and to accounting for actual refinery utilization in determining the year 1990 refinery activity factors. The CH, emissions of 0.848 million tons for 1990 may be contrasted with an estimate of 0.392 million tons in the previous API study. The difference in the methane estima
20、tes can be attributed to the inclusion of production tank emissions and the use of updated activity factors in this study. ES-2 STD-APIIPETRO PUBL LibLiS-ENGL 1447 m 0732240 05b3400 3b8 = Table ES-I. Estimated and Projected Emissions of Greenhouse Gases from the Total carbon dioxide emissions are pr
21、ojected to increase slightly from 284 million tons in 1990 to 288 million tons in the year 2000. Emissions of CO2 are projected to decrease in the crude transport segment, but increase slightly in the other industry segments. Projected annual emissions of methane show a reduction of 0.239 million to
22、ns over the period, This reduction occurs primarily in the exploration and production segment due to reductions in both the emission factors and the activity factor (amount of crude produced). The Global Warming Potentials (GWP) recommended by the IPCC and developed by other studies allow scientists
23、 to compare the ability of each greenhouse gas to trap heat in the atmosphere relative to other gases. The I00 year GWP for carbon dioxide is 1 and for methane it is 24.5. This means that each ton of methane has about 25 times more global warming impact than a ton of carbon dioxide. When adjusted fo
24、r GWP, Table ES-2 shows that greenhouse gas emissions (COz and CH,) from the U.S. petroleum industry will decrease by 0.6% from 1990 to 2000. Table ES-2. Estimated and Projected GWP-Adjusted Emissions of Greenhouse Gases STD.API/PETRO PUBL 4b45-ENGL 1997 0732290 05b3401 2TLi W SENSITIVITY ANALYSIS M
25、ost of the emission factors used in this study were developed from limited samples of emission measurements. This studys estimate could be further refined in the future if more detailed data become available. No such estimates exist today, although an ongoing study by the U.S. EPA Office of Research
26、 and Development (ORD), “Mefhane missions from the Petroleum /ndustry,”may provide that detail for methane in the near future. General sensitivity examinations were conducted to examine key sources of emissions. For CO2, the top four emission sources are: drilling, refinery thermal processes, refine
27、ry atmospheric separation, and catalytic hydrorefining. The activity factors for these categories are expected to be fairly constant over the ten year period examined in this study, and the emission factors from these sources are known with a reasonable level of certainty. Therefore, the CO, estimat
28、es in this study do not appear to be very sensitive to the assumptions made. The general sensitivity examination for methane revealed that the largest single emission source is production tanks and the second largest is production “fugitives, maintenance, and venting nevertheless, the trend in metha
29、ne emissions is downward from the 1990 levels. As indicated in Table ES-2, the CO, emissions dominate the GWP-adjusted emissions from the U.S. petroleum industry. Therefore, the total estimates of greenhouse gas emissions from the petroleum industry are not likely to be very sensitive to the assumpt
30、ions made, despite the greater uncertainty in the methane emissions. CONCLUSIONS The estimated emissions resulting from this study showed that current estimates of greenhouse gas emissions from the United States petroleum industry are reasonably consistent with previous estimates and that little cha
31、nge is expected in these emissions from 1990 to 2000. ES-5 Section 1 INTRODUCTION I The objective of this project is to revise and update the methodology and inventory for methane (CH,) and carbon dioxide (CO,) emissions from the United States petroleum industry. API had previously estimated global
32、emissions of methane and carbon dioxide from petroleum sources in reports issued in I991 -1 992 (Radian 1991 ; Radian 1992). This project focuses on emissions from the United States and updates the estimates for the production of crude through the transport of refinery products. This effort has been
33、 divided into four tasks: Task 1: Task 2: Task 3: Task 4: Comparison of Methodologies-This task compares the attributes of available methodologies and the relative applicability to emissions from the U.S. petroleum industry (see Section 2). 1990 Emission Estimate-To the extent possible, the methodol
34、ogy outlined by the Intergovernmental Panel on Climate Change (IPCC) is used in this task to update the previous methane and carbon dioxide emission estimates for the year 1990 (see Section 3). Data from other sources are used as necessary. Selection of Methodology for Projecting Emissions-This task
35、 reviews methods for projecting U.S. petroleum industry emissions to the year 2000 and recommends an approach (see Section 4). Estimation of Emissions for the Year 2000-Based on recommendations outlined in Task 3, this task computes methane and carbon dioxide emission estimates for the year 2000 (se
36、e Section 5). PETROLEUM INDUSTRY BOUNDARY DEFINITION Boundaries define what is considered the “petroleum industry“ and can exclude certain equipment that is not directly related to the petroleum industry. Boundaries must be 1-1 STD.API/PETRO PUBL Lib45-ENGL 1997 0732290 05b3Li04 TO3 established for
37、the petroleum industry that are technically reasonable, and that match the boundaries used by other accepted U.S. studies such as the GRI/EPA methane emissions study for the natural gas industry (Radian, 1996). The petroleum industry can be broken into distinct segments so that data from existing re
38、ports can be compared on a consistent basis, and so that segments excluded by certain reports become more readily apparent. Based upon examination of existing emission estimates, the following four segments provide the most consistent approach: 1) Production (exploration/extraction)-This includes al
39、l well and surface production equipment, including storage tanks associated with domestic crude production; 2) Crude transportation-This includes all truck, marine, rail, and pipeline transportation of crude, including imported crude; 3) Refining-This includes crude storage tanks, all refinery units
40、, and finished product tanks; 4) Product transportation-This includes all transport of refinery products by truck, marine, rail, and pipelines. Figure 1-1 shows a simplified conceptual diagram of these industry segments. Because oil and gas can be produced from the same well, the production segment
41、presents some interesting boundary issues, where some equipment may be related solely to natural gas production, and therefore may not be part of the petroleum industry. Figure 1-2 shows the production sector boundary definitions as defined in the GRI/EPA methane emissions study (Radian, 1996a). The
42、 GRVEPA study of methane emissions from the natural gas industry deals with the production boundary issue on an equipment level detail. Although the GRVEPA report specified the natural gas industry boundaries, by inference all items outside of the gas industry boundaries are petroleum industry equip
43、ment. Experts from API member companies participated in determining 1-2 STD-API/PETRO M E E .- .I 8 c) 5 13 a a 1-3 STD-API/PETRO PUBL 4bLiS-ENGL 1777 0732270 05b340b 88b Petroleurn Industry Wellhead Oil Well Salt Water and Oil Stock Tanks Coal Bed Compressor Dehydrator Methane Well m Fresh Water De
44、hydrator A+ Chemical Injection pump - Compressor A s +-o C 9 :-U Gas Well Wellbead Eo Field Use Gas Vapor Recovery Compressor Condensace or Oil Tank Control Valve Petroleum Industry U Figure 1-2. Industry Boundaries. 1 -4 STD.API/PETRO PUBL the boundary definition used in the GRVEPA report. Therefor
45、e this report recommends the production boundaries shown in Figure 1-2. All downstream equipment in crude transportation are included within the petroleum industry boundaries. Refining includes all refinery equipment and tanks (crude and product tanks). Aromatics and isomerization processes in refin
46、eries are also included. However, the refinery boundary excludes the downstream chemical plant operations such as steam cracking ethylene plants, plastic/rubber operations, etc., even though these operations may sometimes be integrated within a refinery complex. The refinery boundaries are consisten
47、t with those used by The Oil and Gas Journal for reporting refining activities (Thrash, 1991). Product transport includes all refinery fuel products, but similar to the refining segment, it excludes chemical plant products. i 3 3 3 ! I 3 i ! I Section 2 COMPARISON OF METHODOLOGIES The strengths and
48、weaknesses of various recommended methodologies for estimating methane and carbon dioxide emissions from the petroleum industry are compared in this section. This effort centers on the comparison of other, more recent methodologies and inventories to the earlier API reports on greenhouse gas emissio
49、ns: API Global Emissions of Methane from Petroleum Sources (Radian, 1991). API Global Emissions of Carbon Dioxide from Petroleum Sources (Radian, 1992). The scope of the methodology comparison was limited to evaluation of the following four sets of reports: EPA Office of Air and Radiation Reports: IPCC: E activity factor, which is an equipment or unit population or level of activrty; and emission factor, which is the emission rate per equipment or emission rate per activity. - The evaluation of methodologies involved examination of both the emission factor and activity factor source
