1、Ignition Risk of Hydrocarbon Liquids and Vapors by Hot Surfaces in the Open AirAPI RECOMMENDED PRACTICE 2216THIRD EDITION, DECEMBER 2003REAFFIRMED, OCTOBER 2010Ignition Risk of Hydrocarbon Liquids and Vapors by Hot Surfaces in the Open AirDownstream SegmentAPI RECOMMENDED PRACTICE 2216THIRD EDITION,
2、 DECEMBER 2003REAFFIRMED, OCTOBER 2010SPECIAL NOTESAPI publications necessarily address problems of a general nature. With respect to partic-ular circumstances, local, state, and federal laws and regulations should be reviewed.API is not undertaking to meet the duties of employers, manufacturers, or
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13、, recording, or otherwise, without prior written permission from the publisher. Contact the Publisher, API Publishing Services, 1220 L Street, N.W., Washington, D.C. 20005.Copyright 2003 American Petroleum InstituteFOREWORDRecommended Practice 2216 Ignition Risk of Hydrocarbon Liquids and Vapors by
14、HotSurfaces in the Open Airwas prepared under the auspices of the API Safety and Fire Protec-tion Subcommittee. It is intended to provide information concerning the technical basis forauto-ignition of hydrocarbon vapors by hot surfaces in the open air. This information may beused to determine whethe
15、r or not hot surfaces are potential sources of ignition should arelease of hydrocarbon vapors or liquids occur and to develop safe practices for controllingor preventing such ignition. Other documents referenced in this publication provide supple-mental information applicable to this subject.API pub
16、lications may be used by anyone desiring to do so. Every effort has been made bythe Institute to assure the accuracy and reliability of the data contained in them; however, theInstitute makes no representation, warranty, or guarantee in connection with this publicationand hereby expressly disclaims
17、any liability or responsibility for loss or damage resultingfrom its use or for the violation of any federal, state, or municipal regulation with which thispublication may conflict.Suggested revisions are invited and should be submitted to API, Standards department,1220 L Street, NW, Washington, DC
18、20005.iiiCONTENTSPage1 GENERAL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Applicability. .
19、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3 Non-applicability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 DEFINITIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20、. . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 AUTO-IGNITION TEMPERATURE TESTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.2 Auto-ignition T
21、emperature Testing Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.3 Standard ASTM Auto-ignition Test Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.4 Open Air Auto-ignition Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22、 . 23.5 Gasoline and Oxygenate Blends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 IGNITION BY HOT SURFACES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34.1 Equipment Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . .
23、. . . . . . . . . . . . . . . . . . . . . . 34.2 Sides of Storage Tanks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44.3 Ignition of Heavy Oils by Hot Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 SUMMARY. . . . . . . . . .
24、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45.2 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25、. . . . . . . . . . . . . . . . . . . . . . . . . . . 46 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Tables1 Auto-ignition Temperatures of Hydrocarbon Liquids at Two DifferentPressures . . . . . . . . . . . . . . . . . .
26、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Open Air Auto-ignition Tests under Normal Wind and Convection Current Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Effect of Ignition
27、Lag Time on Auto-ignition Temperature . . . . . . . . . . . . . . . . . . . 34Effect of Wind Velocity in Auto-ignition Tests Using Kerosene . . . . . . . . . . . . . . . 35 Auto-ignition Temperatures of Motor Fuels (NFPA 325) . . . . . . . . . . . . . . . . . . . . 3v1Ignition Risk of Hydrocarbon Li
28、quids and Vapors by Hot Surfaces in the Open Air1 GENERAL1.1 SCOPE This recommended practice provides information concern-ing the potential for ignition of hydrocarbons that are exposedto hot surfaces in the open air. Hydrocarbon liquids, whenheated sufficiently, can ignite without the application o
29、f aflame or spark. The ignition of hydrocarbons by hot surfacesmay occur when oil is released under pressure and sprays ona hot surface or is spilled and lies on a hot surface for a periodof time. Understanding the mechanism and dynamics of auto-ignition is an important step in preventing or control
30、ling theignition of hydrocarbons by hot surfaces in the open air. Inaddition to the information provided herein, appropriateindustry standards and other information may assist users tounderstand the potential hazards of hydrocarbon auto-ignition(such as spontaneous combustion) not specifically cover
31、ed bythis publication and implement appropriate prevention andcontrol measures.1.2 APPLICABILITYHot surfaces, in areas where hydrocarbon liquids or vaporsare present and may be released, are often presumed to be thesources of ignition should fires occur. However, it is generallyrecognized by the pet
32、roleum industry that hot surfaces, evenat temperatures considerably above the auto-ignition temper-atures (AIT) of the hydrocarbons involved, are not alwayscapable of igniting flammable vapor-in-air mixtures. Thispublication provides information applicable to the betterunderstanding and controlling
33、of hot surface ignition hazards. 1.3 NON-APPLICABILITY This recommended practice does not cover every possiblehazard or situation that may involve ignition of hydrocarbonliquids and vapors from hot surfaces. This publication doesnot apply to the ignition of hydrocarbons when certain condi-tions occu
34、r, such as spontaneous combustion (see 2.2). Themechanism for spontaneous combustion is entirely differentfrom that required for ignition of hydrocarbon vapors fromcontact with hot surfaces in open air. This publication alsodoes not apply to the ignition of hydrocarbon vapors whencontacted by heated
35、 or glowing metal such as welding slag orby direct impact of super-hot exhaust fumes or gases. In addi-tion, this publication does not cover ignitions arising fromhydrocarbon liquids trapped behind rust or oil soaked or satu-rated insulation or rust covering hot surfaces. 2 DEFINITIONS2.1 Auto-ignit
36、ion:The ignition of a material (commonlyin air) as the result of heat liberation due to an exothermicoxidation reaction in the absence of an external ignitionsource such as a spark or flame. 2.2 Auto-ignition Temperature (AIT):The AIT of asubstance is the minimum temperature required to initiate orc
37、ause self-sustained combustion (exothermic reaction) inde-pendent of an external ignition source. As used in this publica-tion, it is the minimum temperature at which auto-ignitionoccurs under the specified conditions of the ASTM E 659 test1(see Section 6). The terms, “auto-ignition temperature,” “i
38、gni-tion temperature,” “self ignition temperature,” “autogenousignition temperature,” and “spontaneous ignition temperature,”are used synonymously in this publication. ASTM E 659.3AUTO-IGNITION TEMPERATURE TESTING3.1 GENERALThis recommended practice covers the technical basis forthe risk of ignition
39、 of hydrocarbons by hot surfaces based onAIT and the practical implications thereof. An understandingof AIT is important when hydrocarbon vapors or liquids areexposed to hot surfaces or when handling very hot hydrocar-bon liquids. It should be understood that ignition of flamma-ble hydrocarbon vapor
40、s by a hot surface at the minimumignition temperatures (for the specific hydrocarbon) is notlikely. Experimental studies, testing and practical experiencehave shown that hot surfaces must typically be hundreds ofdegrees above published minimum ignition temperatures toignite freely moving hydrocarbon
41、 vapor in the open air. Evenproperly operating automotive vehicle catalytic exhaust sys-tems, in most instances, do not create a surface temperaturesufficiently high enough to ignite hydrocarbon vapors in theopen air2. Whether or not flames will develop when a hydro-carbon contacts a hot surface dep
42、ends not only on the surfacetemperature, but also on the extent (size) of the hot surface, itsgeometry and the ambient conditions3. The following information, covering AIT research, isintended to assist in understanding why the ignition of hydro-carbon vapors by hot surfaces (at published minimum AI
43、Ts),is highly improbable.3.2 AUTO-IGNITION TEMPERATURE TESTING CRITERIAAlthough the definition for “auto-ignition temperature” isspecific, the values observed when testing specific hydrocar-bons will be different depending on the conditions at the timeof testing and the test method used. AITs observ
44、ed under oneset of conditions may be changed substantially by differentconditions4. Some of the variables that affect AITs are themolecular structure of the hydrocarbon mixture (i.e., gaso-2 API RECOMMENDEDPRACTICE2216line), the percentage composition of the vapor-in-air mixture,the shape, size and
45、configuration of the space and the hot sur-face, the hot surface material, the type and reactivity of othermaterials present, the rate and duration of heating, and envi-ronmental conditions such as the initial temperature and theatmospheric pressure (see Table 1). Time lags of a minute or more durin
46、g AIT testing arecommon5. Additionally, the AIT is lower if the test vessel size(or test surface area) is larger, the heat of combustion isgreater, the pressure is higher, the hydrocarbon molecularweight is larger or the mixture conductivity is smaller6. All ofthese factors affect the ability to acc
47、urately predict conditionsunder which auto-ignition will occur when hydrocarbons con-tact heated surfaces.3.3 STANDARD ASTM AUTO-IGNITION TEST METHODSThe majority of reported AIT data has been previouslyobtained by one of two standard AIT test methods, ASTMD 286 and D 2155. These two original test m
48、ethods7(which have now been withdrawn by the American Societyfor Testing and Materials) involved introducing small mea-sured amounts of flammable or combustible liquids intoglass flasks that are uniformly heated with air without anexternal source of ignition. If ignition occurred, the flaskwall temp
49、erature and the time for ignition to occur afterintroduction of the sample (ignition lag) were noted. Thetests were repeated using different flask wall temperaturesto determine the lowest temperature at which ignitionwould occur in less than 10 min., which was then reportedas the minimum ignition temperature of the liquid tested.Because both of these former test methods relied on visualdetection of a flame, the ignition temperatures obtainedwere the minimum temperatures at which flame ignitionswere visually observed. The current ASTM test standards1, ASTM D 2883 andASTM E 659, also use the h
