1、Designation: G 72 01Standard Test Method forAutogenous Ignition Temperature of Liquids and Solids in aHigh-Pressure Oxygen-Enriched Environment1This standard is issued under the fixed designation G 72; the number immediately following the designation indicates the year of originaladoption or, in the
2、 case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This method covers the determination of the tempera-ture at which liquids and solids w
3、ill spontaneously ignite.These materials must ignite without application of spark orflame in a high-pressure oxygen-enriched environment.1.2 This method is intended for use at pressures of 2.1 to20.7 MPa (300 to 3000 psi). The pressure used in thedescription of the method is 10.3 MPa (1500 psi). The
4、 method,as described, is for liquids or solids with ignition temperaturein the range from 60 to 425C (140 to 800F).1.3 This method is for high-pressure pure oxygen. Themethod may be used in atmospheres from 0.5 % to 100 %oxygen.1.4 An apparatus suitable for these requirements is de-scribed. This met
5、hod could be applied to higher pressures andmaterials of higher ignition temperature. If more severe re-quirements or other oxidizers than those described are desired,care must be taken in selecting an alternative safe apparatuscapable of withstanding the conditions.1.5 This standard does not purpor
6、t to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 1193
7、 Specification for Reagent Water2G 93 Practice for Cleaning Methods and Cleanliness Levelsfor Material and Equipment Used in Oxygen-EnrichedEnvironments32.2 Federal Specification:4BB-O-925 Oxygen, Technical, Gas and Liquid2.3 Other Documents:MNL 36 Safe Use of Oxygen and Oxygen Systems: Guide-lines
8、for Oxygen System Design, Materilas, Selection,Operations, Storage, and Transportation5Compressed Gas Association Booklets G-1 and G-4.12,43. Summary of Method3.1 This autogenous ignition temperature test method isdesigned to expose solid or liquid sample material to increasingtemperature in a high-
9、pressure reaction vessel. The reactionvessel (bomb), including a sample holding assembly, is pres-surized with the oxygen-enriched environment. The bomb isheated in an electric furnace at a predetermined rate. Thetemperature of the sample-holding assembly is monitored as afunction of time by means o
10、f a thermocouple and recordingpotentiometer.3.2 The minimum temperature required to cause the sampleto ignite spontaneously is determined at any selected systempressure. The point at which spontaneous ignition occurs isdenoted by a sudden rise in temperature and the destruction ofthe sample. The amo
11、unt of rise in temperature is related to thesample size. A sample size is selected to prevent damage to theequipment caused by exceeding safe system pressure ortemperature limits because of the temperature rise.3.3 The system is pressurized to the desired test pressure atthe start of the test. Durin
12、g the test as the temperature isincreased, the pressure increases. No effort is made to controlthe pressure during the test. It is monitored only so that thepressure does not exceed a safe limit for the test equipment.4. Significance and Use4.1 Most organic liquids and solids will ignite in a pressu
13、r-ized oxidizing gas atmosphere if heated to a sufficiently hightemperature and pressure. This procedure provides a numericalvalue for the temperature at the onset of ignition undercarefully controlled conditions. Means for extrapolation fromthis idealized situation to the description, appraisal, or
14、 regula-tion of fire and explosion hazards in specific field situations,are not established. Ranking of the ignition temperatures of1This method is under the jurisdiction of ASTM Committee G4 on Compatibilityand Sensitivity of Materials in Oxygen Enriched Atmospheres and is the directresponsibility
15、of Subcommittee G04.01 on Test Methods.Current edition approved Sept. 10, 2001. Published January 2002. Originallypublished as G 7282. Last previous edition G 7282(1996)e1.2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 14.02.4Available from Compressed Gas Assn., 500 Fi
16、fth Ave., New York, NY 10110.5ASTM Manual Series, Available from ASTM, 100 Barr Harbor Drive, W.Conshohocken, PA 19428.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.several materials in the standard apparatus is generally inconform
17、ity with field experience.4.2 The temperature at which material will ignite spontane-ously (AIT) will vary greatly with the geometry of the testsystem and the rate of heating. To achieve good interlaboratoryagreement of ignition temperatures, it is necessary to useequipment of approximately the dime
18、nsions described in themethod. It is also necessary to follow the described procedureas closely as possible.4.3 The decomposition and oxidation of some fully fluori-nated materials releases so little energy that there is noclear-cut indication of ignition. Nor will there be a clearindication of igni
19、tion if a sample volatilizes, distilling toanother part of the reaction vessel, before reaching ignitiontemperature.5. Apparatus5.1 Suitable components shall be assembled so that thespecified reaction vessel (bomb), including sample-holdingassembly, can be charged with oxygen and heated. Theassembly
20、 shall provide a means of recording time and tem-perature at which ignition occurs. A suitable assembly isillustrated in Fig. 1.5.2 Cylinder Oxygen, conforming to Federal SpecificationBB-O-925, Type I or oxygen of 99.5 % minimum purity.Oxygen of higher purity may be used if desired.5.3 Line Filter,
21、sintered stainless steel, 5-m porosity,maximum pressure 206.8 MPa (30 000 psi), for 6.35-mm (14-in.) high-pressure tubing with a 3.18-mm (18 -in.) port.65.4 Compressor Pumps, diaphragm-type, air-driven.75.5 Valves, 6.35 mm (14 in.), 206.8 MPa (30 000 psi)working pressure, nonrotating stem valves.85.
22、6 Pressure Gage, 20.7 MPa (3000 psi), 216 mm (812 in.).9Heise 2 or equivalent has been found satisfactory.5.7 Connecting Tubing, Type 316 stainless steel, 6.35 mm(14 in.), 448.1 MPa (65 000 psi) pressure rating at 37.8C(100F).105.8 High-Pressure Tees, Type 316 stainless steel with glandnuts and slee
23、ves of Type 416 stainless steel, 6.35 mm (14 in.)high-pressure. Superpressure, Inc., Catalog No. 45-14311.11All connection fittings shall be of cold-drawn Type 316stainless steel, 413.7 MPa (60 000 psi) maximum pressure,tubing size 6.35 mm (14 in.) high-pressure and 14.3-mm (916-in.) insertion depth
24、.125.9 Pressure-Relief Blowout with Rupture Discs, pressure-relief blow-out assembly, Type 316 stainless steel, 6.35 mm (14in.), angle type13with 48.3 MPa (7000 psi) at 22.2C (72F)rupture disks.145.10 Reaction Vessel (Bomb)A suitable reaction vessel forthe method is cylindrical, approximately 65 mm
25、(2916 in.) inoutside diameter and 298 mm (1134 in.) long and weighs 9.75kg (2112 lb). The vessel is bored from a solid forging of AISI316SS (814 in.) depth, with a volume equal to approximately6Catalog No. 49-14405 available from Superpressure, Inc., Silver Spring, Md.20910 or equivalent has been fo
26、und satisfactory.7Catalog No. 46-14035 available from Superpressure, Inc., Silver Spring, Md.20910 or equivalent has been found satisfactory.8Catalog No. 44-13121 available from Superpressure, Inc., Silver Spring, Md.20910 or equivalent has been found satisfactory.9Model C available from Heise Bourd
27、on Tube Co., Newton, Conn. 06740 orequivalent has been found satisfactory.10Catalog No. 45-11021 available from Superpressure, Inc., Silver Spring, Md.20910 or equivalent has been found satisfactory.11Catalog No. 45-14311 available from Superpressure, Inc., Silver Spring, Md.20910 or equivalent has
28、been found satisfactory.12Catalog No. 45-11311 available from Superpressure, Inc., Silver Spring, Md.20910 or equivalent has been found satisfactory.13Catalog No. 45-19123 available from Superpressure, Inc., Silver Spring, Md.20910 or equivalent has been found satisfactory.14Catalog No. 45-19210 ava
29、ilable from Superpressure, Inc., Silver Spring, Md.20910 or equivalent has been found satisfactory.FIG. 1 AIT Equipment AssemblyG72012110 mL. The maximum working pressure at 427C (800F) is82.7 MPa (12 000 psi).155.11 Thermocouple AssemblyA Chromel-Alumel thermo-couple with suitable high-pressure fit
30、tings for the reactionvessel with a 203-mm (8-in.) thermocouple to extend into thereaction chamber.165.12 Heating JacketA 230-V, 1000-W single-phase heat-ing jacket designed to fit the reaction vessel should be used.175.13 Recorder, 0 to 1000C (0 to 2000F)A strip chartrecording pyrometer in the temp
31、erature range for the methodshould be used.18The scale must be such that a sudden changeof 20C (36F) or more in temperature in the reaction vessel isclearly indicated.5.14 Inner Reaction VesselA borosilicate glass test tube15 by 125 mm.195.15 Sample HolderA borosilicate glass culture tube 10by 75 mm
32、.205.16 Wire Support, fashioned from Chromel A, No. 21 AWGwire.10Several turns of wire are wound on a mandrel ofsufficient size so that the resulting spring-like structure fits theinner reaction vessel snugly. A loop of wire is bent to hold thevessel at the proper height, positioning the thermocoupl
33、eassembly in the mouth of the sample holder (Fig. 2).5.17 Support Bushing, fitting into the reaction vessel coverand supporting the entire sample-holding assembly.215.18 Inner Reaction Vessel Stopper, fashioned from12.5-mm borosilicate glass tubing to fit in the inner reactionvessel. It must also co
34、nform to the dimensions in Fig. 3.6. Materials6.1 Nitric AcidConsisting of 5% by volume of AnalyticalReagent grade nitric acid and deionized water.6.2 Alkaline CleanerConsisting of a solution of 15 g ofsodium hydroxide (NaOH), 15 g of trisodium phosphate(Na3PO4), and 1 L of distilled or deionized wa
35、ter.6.3 Deionized or Distilled Water, conforming to Specifica-tion D 1193, Type IV.6.4 Oxygen, conforming to Federal Specification BB-0-925,Type I or oxygen of 99.5 % purity. Oxygen of higher puritymay be used if desired.7. Safety Precautions7.1 Nitric Acid:Warning! Harmful by inhalation, skin conta
36、ct, and ifswallowed.Although not combustible, is a powerful oxidizing agent,which may cause combustible materials to ignite.Wear appropriate NIOSH-approved respirator, chemical re-sistant gloves (Butyl rubber), safety goggles.7.2 Sodium Hydroxide:Warning!Harmful by inhalation, skin contact, and if s
37、wal-lowed.Use adequate ventilation.Wear face shield, lab coat, rubber apron.Store away from strong acids7.3 Oxygen:Warning!Oxygen vigorously accelerates combustion.Keep oil and grease away. Do not use oil or grease onregulators, gages, or control equipment.Use only with equipment conditioned for oxy
38、gen service bycarefully cleaning to remove oil, grease, and other combus-tibles.Keep combustibles away from oxygen and eliminate ignitionsources.Keep surfaces clean to prevent ignition or explosion, or both,on contact with oxygen.Always use a pressure regulator. Release regulator tensionbefore openi
39、ng cylinder valve.All equipment and containers used must be suitable andrecommended for oxygen service.Never attempt to transfer oxygen from cylinder in which it isreceived to any other cylinder. Do not mix gases in cylinders.Do not drop cylinder. Make sure cylinder is secure at alltimes.Keep cylind
40、er closed when not in use.Stand away from outlet when opening cylinder valve.For technical use only. Do not use for inhalation purposes.15Type B Reaction Vessel Catalog No. 41-12555, available from Superpressure,Inc., Silver Spring, Md. 20910 or equivalent will meet these requirements.16Thermocouple
41、 Assembly Catalog No. 45-17620 available from Superpressure,Inc. or equivalent can be used.17Heating Jacket, Catalog No. 43-12113 available from Superpressure, Inc., orequivalent can be used.18Strip chart recorders available from Honeywell, Inc., 2701 4th Ave., Minne-apolis, Minn. 55408 or equivalen
42、t can be used.19Catalog No. 9800, available from Corning Glass Works, Houghton Park,Corning, NY 14830 or equivalent can be used.20Catalog No. 9820 available from Corning Glass Works, Houghton Park,Corning, NY 14830 or equivalent has been found satisfactory.21Catalog No. 15-21AF1HM4-T available from
43、High Pressure Equipment Co.,1222 Linden Ave., Erie, PA. 16505 or equivalent has been found satisfactory.FIG. 3 Inner Reaction Vessel StopperG72013Keep cylinder out of sun and away from heat.Keep cylinder from corrosive environment.Do not use cylinder without labelDo not use dented or damaged cylinde
44、rs.7.3.1 See Compressed Gas Association booklets G-4 andG-4.1 for details of safe practice in the use of oxygen.8. Procedure8.1 Clean all components of the system as follows:8.1.1 Soak glass parts in chromic acid cleaning solution,rinse in distilled water, and dry.8.1.2 Clean stainless steel compone
45、nts by immersing in analkaline cleaner (see 6.2) for a minimum of 15 min at 20 to 35C. Follow the immersion with a thorough rinse in running tapwater, followed by a thorough rinse in distilled or deionizedwater. Perform a water break test during the rinsing step toverify that organic material has be
46、en removed. Blow dry withclean, dry, oil-free nitrogen to remove the excess water, placein an oven at 52 to 66C until free of water. Components maybe cleaned using any process that will produce a cleanlinesslevel at least as good as the level provided by the aboveprocess. Follow Practice G 93 or AST
47、M Manual Series MNL36 recommended procedures.8.2 Weigh out a 0.20 6 0.03-g sample, either in liquid orsolid form, into the sample holder.8.3 Assemble equipment as shown in Fig. 1 and Fig. 2, andas directed by the reaction vessel manufacturer.8.4 Flush the system twice with oxygen, meeting the re-qui
48、rements of 5.1, by pressurizing the system to 5.0 MPa (725psi) and releasing the pressure.8.5 Fill the reaction vessel with the oxygen specified in 7.3to a pressure of 11.5 MPa (1650 psi) and allow to stand at roomtemperature for 15 min. The pressure will drop approximately0.5 MPa (45 psi) while the
49、 gas cools, but should remain nearlyconstant thereafter. A steady pressure drop indicates a systemleak which must be corrected before proceeding. After assuringthe absence of leaks, adjust the pressure to 10.3 MPa (1500psi).8.6 Start the reaction vessel heating jacket and the recorder.Heat the reaction vessel at a rate of 5 6 1C (9 6 1F)/min.This rate of heating should be maintained from 60 to 260C(140 to 500F). Above 250C (500F), difficulty may beFIG. 2 Sample Holding AssemblyG72014encountered maintaining this heating rate, but it must bemain
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