1、Q AGA American Gas Association Odorization Manual Prepared by Transmission Measurement Committee and Former Chemical and Analytical Services Task Committee Operating Section American Gas Association 400 North Capitol Street, N.W., 4“ Floor Washington, DC 20001 U.S.A. REVIS ED DECEMBER 2000 Catalog N
2、o. XQ0005 Copyright O 2000 American Gas Association All Rights Reserved d AGA American Gas Association Odorization Manual REVISED DECEMBER 2000 Copyright O 2000 American Gas Association All Rights Reserved Prepared by Transmission Measurement Committee and Former Chemical and Analytical Services Tas
3、k Committee Operating Section American Gas Association 400 North Capitol Street, N.W., 4th Floor Washington, DC 20001 U.S.A. Catalog No. XQ0005 I II DISCLAIMER AND COPYRIGHT Nothing contained in this manual is to be construed as granting any right, by implication or otherwise, for the manufacture, s
4、ale or use in connection with any method, apparatus or product covered by letters patent, or as insuring anyone against liability for infringement of letters patent. This manual may be used by anyone desiring to do so. Efforts have been made to ensure the accuracy and reliability of the data contain
5、ed in this publication; however, the American Gas Association (AGA) makes no representation, warranty or guarantee in connection with this manual and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use; for any violation of any federal, state or munic
6、ipal regulation with which this manual may conflict; or for the infringement of any patent from the use of this manual. Nothing contained in this manual should be viewed as an endorsement by AGA of any particular manufacturers products. Permission is granted to republish material herein in laws or o
7、rdinances, and in regulations, administrative orders, or similar documents issued by public authorities. Those desiring permission for other publication should consult the Operating and Engineering Section, American Gas Association, 400 North Capitol Street, NW, 4th Floor, Washington, DC 20001, U.S.
8、A. Copyright O 2000 American Gas Association, All Rights Reserved iii ACKNOWLEDGMENTS This manual is dedicated in memory of Tim Johnson, formerly president of Natural Gas Odorizing Inc. From the first meeting of the former AGA Chemical and Analytical Services Task Committee, Tim was unwavering in hi
9、s goal to provide the natural gas industry with an improved and substantial “Odorization Manual.” It is largely due to Tims encouragement and expertise that this project reached its completion. We will miss his persistence, knowledge and humor. The first draft of this revised manual was compiled by
10、Rosemarie Halchuk- Harrington of Xcel Energy. She also prepared the final version after reviewing the comments from the Operating Section Managing Committee. AGA greatly appreciates her efforts in getting this document completed and extends its thanks for her contribution. Craig Caldwell from Nation
11、al Fuel Gas Supply Corp. was of great help in consolidating and reviewing the comments from AGAS Transmission Measurement and Distribution Measurement committees. AGA extends thanks to him as well. In addition, the following people deserve thanks for their comments and support in preparation of the
12、document. James Avioli, Williams Gas Pipeline -Transco, Houston, Texas Thomas Bonner, Boston Gas Co., West Roxbuty, Massachusetts Frank Brown, CMS Energy, Houston, Texas Willard Carey, Public Service Electric Elf Atochem of North America, Philadelphia, Pennsylvania Joseph Ranney, Southern California
13、 Gas Co., Los Angeles, California David Reistetter, San Diego Gas or b. An area where the pipeline lies within 100 yards of either a building or a small, well-defined outside area (such as a playground, recreation area, outdoor theater or other place of public assembly; that is occupied by 20 or mor
14、e people on at least five days a week for 10 weeks in any 12-month period. (The days and weeks need not be consecutive.) Class 4. A Class 4 location is any class location unit where buildings with four or more stories above ground are prevalent. Exceptions: The length of class locations 2, 3 and 4 m
15、ay be adjusted as follows: a. A Class 4 location ends 220 yards (200 meters) from the nearest building with four or more stories above ground. b. When a cluster of buildings intended for human occupancy requires a Class 2 or 3 location, the Class 2 or 3 location ends 220 yards (200 meters) from the
16、nearest building in the cluster. The following diagrams are typical examples that illustrate class determination. 3 Class 1 r 1 Pipeline 10 or fewer buildings per mile for human occupancy 1 mile O Or Offshore Class 2 More than 10 and less than 42 buildings per mile for human occupancy 4 Class 3 Pipe
17、line I 1 O Pipeline 1 mile 46 or more buildings per mile for human occupancy c - Or any area where a pipeline is within 100 yards of the following: Pipeline Small, defined outside area occupied by 20 or more people, such as a playground, recreation area, outdoor theater, or public assembly place 5 C
18、lass 4 J. A 220 yards Any location where buildings with four or more stories above ground are prevalent EXCEPTIONS Adjustments to Class 2, 3, or 4 Class 2 or 3 location that ends 220 yards from the nearest building in a cluster of buildings intented for human occupanc) 11 Class 2 or 3 location ends
19、Pipeline 6 1.4.2 Exemptions from Odorization Requirements The federal regulations require that gas in a transmission line in a Class 3 or 4 location must be odorized unless one of the following three conditions pertain: 1. in a Class 1 or Class 2 location. At least 50 percent of the length of the li
20、ne downstream from that location is 2. without any odorant from that line before May 5, 1975: The line transports gas to any of the following facilities that received gas a. an underground storage field; b. a gas processing plant; c. d. a gas dehydration plant; or an industrial plant using gas in a
21、process in which the presence of an odorant adversely affects the product. 3. least 50 percent of the length of that line is in a Class 1 or Class 2 location. In the case of a lateral line, that transports gas to a distribution center, at 7 CHAPTER 2 Component Tertiary Butyl Crew Mercaptan Isopropyl
22、 Mercaptan WM) Normal Propyl Mercaptan WM Butyl Mercaptan (SEM) Secondafy CHEMICAL AND PHYSICAL PROPERTIES OF ODORANTS Sulfur Boiling Freezing Specific -Densi*- S Contribution Chemical Chem. Molar Concentration Point Point Gravity (Ib/gal at at 1 IbAilmcf Structure Abstract No. Mass (wt %) (“ F) (“F
23、) (6O/6O0F) 60F) (graidccf) CH3 90 35 5 148 34 0.799 6.65 0.25 I I CH3-C-SH 75-66-1 CH3 CH34H-CH3 I 75-33-2 76 42.0 127 -262 0.820 6.83 0.30 SH CH3-CH2-CH2-SH 107-03-9 76 42.0 154 -167 0.836 6.96 0.30 CH .e., gas containing significant levels of higher hydrocarbons. * Not a major gas odorant compone
24、nt, usually makes up only 3-6% of the blend. Most easily oxidized mercaptan commonly used in natural gas odorization. * * Strong odor that helps enhance odor of the blend. * Blends together with TBM and IPM. * Useable in both evaporative and liquid injection equipment. * Least used mercaptan in blen
25、ds, generally makes up 2-4% of the blend. High boiling point and low vapor pressure excellent for use in wick odorizers when blended together with TBM, IPM and NPM. Difficult to mask and thus used to boost odor levels in low odor * * level pipelines 2.1.2 Cyclic Sulfides 2.1.2.1 CHEMICAL AND PHYSICA
26、L PROPERTIES Specific Density C Contribution Gravity (Ibigal at at 1 Ib/Mmcf 0.999 L 9 2.1.2.2 ADDITIONAL CHARACTERISTICS Component Tet rah yd rot hio- phene Characteristics * Originally used primarily as single component odorant in Europe. * Commonly blended with TBM. * Most resistant of all compon
27、ents to oxidation. * Exhibits a recognizable “gassy odor.” * Low odor threshold but exhibits lower odor impact than the mercaptans. * Greater adsorption and hence less penetrability in soil than mercaptans and alkyl sulfide. * Achieves plateau effect in the olfactory dose/response curve (.e., the od
28、or intensity does not increase above certain concentrations). * Can be used in injection and evaporative equipment. 2.1.3 Alkyl Sulfides 2.1.3.1 CHEMICAL AND PHYSICAL PROPERTIES Methyl Ethyl Sulfide CH3-S-CH2-CH3 624-89-5 76 42.0 153 -156 0.840 7.00 0.30 fMFC) 10 2.1.3.2 ADDITIONAL CHARACTERISTICS t
29、 Component Dimethyl Sulfide Methyl Ethyl Sulfide Characteristics * Primarily used with TBM. * Very resistant to oxidation. * Best soil penetrability of all odorant components. * Does not exhibit “gassy odor“ by itself. * Introduced as blend component in odorants in 1969. * Very resistant to oxidatio
30、n. * Soil penetrability similar to TBM. * Because of small differences in boiling points of MES and TBM, blends of these two components can be used in either vaporization or liquid-injection type equipment. * Does not exhibit “gassy odor“ by itself. 2.2 ODORANT BLENDS Natural gas odorant blends are
31、divided into four different types: all- mercaptan, mercaptan and alkyl sulfide, cyclic sulfide, and cyclic sulfide and mercaptan. While there are more than 20 different commercially available odorant blends in use by the gas industry, eight blends are most commonly used. There is no single odorizati
32、on rate that can be used in all gas systems. Many factors affect the rate of odorization, including, but not limited to, gas quality and system configuration. Therefore, each system operator must determine a proper rate for the particular system by a testing program to maximize safety and ensure com
33、pliance with all applicable regulations. Liquid injection equipment is suitable for use with any of the odorant blend types. However, blends of TBM/DMS and TBMTTHT are not recommended for vaporization equipment. a The tables below list the eight major blends and are categorized by type. The tables i
34、nclude the chemical composition and properties of the blends. To avoid the use of trade names, the blends are assigned arbitrary numbers with no intended preferences. These eight blends represent approximately 80 percent of all natural gas odorants currently used in North America. 11 2.2.1 All-Merca
35、ptan Blends 2.2.1 .I BLEND #I COMPONENT Tertiary Butyl Mercaptan Isopropyl Mercaptan Normal Propyl Mercaptan CONCENTRATION (wt %) 75-80 15-22 3-6 - Secondary Butyl Mercaptan 0-3 Distillation Specific Density Reid Vapor Cloud Freezing Flash Sulfur S Contribution Range Gravity (Iblgal at Pressure Poin
36、t Point Point Content at 1 IblMmcf 137-1 51 0.809-0.81 2 6.73-6.76 6.4-6.8 -50 99 1 Reid Vapor Cloud Freezing Flash Sulfur S Contribution Pressure Point Point Point* Content at 1 IblMmd 2.2.3 Cyclic Sulfide Blend 2.2.3.1 BLEND #7 COMPONENT Tetrahydrothiophene Tertiary Butyl Mercaptan Distillation Sp
37、ecific Density Range Gravity (Iblgal at (“FI (SOl60”F) 60F) 150-250 0.906-0.937 7.55-7.80 CONCENTRATION (wt %) 50-70 30-50 Reid Vapor Cloud Freezing Flash Sulfur S Contribution Pressure Point Point Point* Content at 1 IblMmcf (psia at 100F) (“F) (“F) (“F) (wt YO) - (grainlccf) 2.5-4.5 -50 C-50 CO 37
38、 0.25 (“F) I (60/6O0F) I 60F) I (p cia at IOOOF) I ( OF) I (“F) I (OF) I ( wt%) I (g rain/Ccf) 239-256 I 0.999 I 8.32-8.35 I 0.7-0.8 I -50 I C-50 I -50 I 36 I 0.25 L *Closed cup 2.2.4 Cyclic Sulfide-Mercaptan Blend 2.2.4.1 BLEND #8 13 CHAPTER 3 ODORIZATION SYSTEM DESIGN CONSIDERATIONS 3.1 LOCATIONS
39、Site selection is typically dictated by individual system configurations, but the following factors should be considered. 3.1.1 Accessibility Odorizers should be readily accessible in all kinds of weather. This is especially important at locations receiving bulk deliveries of odorant. A proper roadb
40、ed and turning radius should be included in the design of the odorizer station. 3.1.2 Population Density Ideally, the location should have a low population density so that any accidental release of odor affects a minimum number of people. However, design considerations should be the same in remote a
41、nd more populated areas: All odorizer stations should be designed to minimize the potential release of odorant into the environment. It should be noted that population density can change rapidly. 3.1.3 Utilities The availability of electricity at the site is important for most odorizer installations
42、. Electricity is convenient for field personnel and may be necessary for some equipment. The absence of electricity, however, need not rule out an otherwise ideal location because of the diversity of equipment available. Telephone service also is useful, especially in the case of a spill or other em
43、ergency. Technical assistance and SCADA communication can reduce downtime and provide remote monitoring capabilities. 3.1.4 Building Codes The system location and design must comply with all pertinent -federal, state and local regulations and codes. 14 3.2 SECONDARY CONTAINMENT Odorization equipment
44、 is currently considered part of the gas transmission and distribution system in the United States and, therefore is regulated by DOT. Although not required by DOT, secondary containment for odorizers and/or the associated storage vessels may be required by some state or local authorities. Secondary
45、 containment should be considered in all initial installations since it is relatively inexpensive to build during initial construction compared with the cost of retrofitting and/or soil remediation after a spill. Secondary containment can be accomplished by use of lined earthen dikes, concrete or me
46、tal type enclosures, or double wall tanks and piping. These systems must be designed not to leak, must be able to contain appropriate volumes of rain and snow, and must provide drainage of the facility. Analytical testing of the product may be required by governmental agencies before draining. Doubl
47、e-walled tanks and enclosed buildings are becoming more popular for that reason. 3.3 BUILDINGS As stated in 3.2, buildings are becoming popular, especially where a harsh environment is a consideration. Enclosed buildings are more expensive than other designs, but have the following benefits. I. Equi
48、pment and personnel are protected from the elements. 2. Air-exchange equipment with exhaust filters/scrubbers for odor control can be installed. 3. Leak-detection monitors can be installed. In addition, the volume of a secondary containment basin can be reduced since allowances for rain or snow are
49、not needed for enclosed odorizers. Fewer analytical tests on accumulated liquids would be required if no external sources of liquid exist. 3.4 ABOVE- AND BELOW-GRADE INSTALLATION Storage tanks and odorizers can be installed above or below the grade. The reasons for installing storage tanks and odorizers below the grade are usually protection from vandalism and/or temperature control. The primary disadvantage is that detection of a potential leak may be delayed and could result in a greater release of odorant. Some states require a double-walled tank with leak detection
