1、Designation: D 381 09An American National StandardStandard Test Method forGum Content in Fuels by Jet Evaporation1This standard is issued under the fixed designation D 381; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers the determ
3、ination of the existentgum content of aviation fuels, and the gum content of motorgasolines or other volatile distillates in their finished form,(including those containing alcohol and ether type oxygenatesand deposit control additivessee Note 7 for additionalinformation) at the time of test.1.2 Pro
4、visions are made for the determination of the heptaneinsoluble portion of the residue of non-aviation fuels.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3.1 The accepted SI unit of pressure is the Pascal (Pa); theaccept
5、ed SI unit for temperature is degrees Celsius.1.4 This standard does not purport 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 regul
6、atory limitations prior to use. For specificwarning statements, see 6.4, 7.4, and 9.1.2. Referenced Documents2.1 ASTM Standards:2D 1655 Specification for Aviation Turbine FuelsD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsE1 Specification for ASTM Liquid-in-Glass Thermometers
7、E29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications2.2 Energy Institute Standard:3IP Standard Methods for Analysis and Testing of PetroleumProductsIP 540 Determination of the existent gum content of avia-tion turbine fuel jet evaporation method3. Termin
8、ology3.1 Definitions of Terms Specific to This Standard:3.1.1 existent gumthe evaporation residue of aviationfuels, without any further treatment.3.2 For non-aviation fuels, the following definitions apply.3.3 solvent washed gum contentthe residue remainingwhen the evaporation residue (see 3.4) has
9、been washed withheptane and the washings discarded.3.3.1 DiscussionFor motor gasoline or non-aviation gaso-line, solvent washed gum content was previously referred to asexistent gum.3.4 unwashed gum contentthe evaporation residue of theproduct or component under test, without any further treat-ment.
10、4. Summary of Test Method4.1 When testing either aviation or motor gasoline, a 50 60.5 mL quantity of fuel is evaporated under controlled condi-tions of temperature and flow of air (see Table 1). When testingaviation turbine fuel, a 50 6 0.5 mL quantity of fuel isevaporated under controlled conditio
11、ns of temperature andflow of steam (see Table 1). For aviation gasoline and aviationturbine fuel, the resulting residue is weighed and reported asmilligrams per 100 mL. For motor gasoline, the residue isweighed before and after extracting with heptane and theresults reported as milligrams per 100 mL
12、.NOTE 1Specification D 1655 allows the existent gum of aviationturbine fuels to be determined by either Test Method D 381 or IP 540, withTest Method D 381 identified as the referee test method. Test MethodD 381 specifically requires the use of steam as the evaporating medium foraviation turbine fuel
13、s, whereas IP 540 allows either air or steam as theevaporating medium for aviation turbine fuels.5. Significance and Use5.1 The true significance of this test method for determininggum in motor gasoline is not firmly established. It has beenproved that high gum can cause induction-system deposits an
14、dsticking of intake valves, and in most instances, it can beassumed that low gum will ensure absence of induction-systemdifficulties. The user should, however, realize that the test1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct
15、 responsibility of SubcommitteeD02.14 on Stability and Cleanliness of Liquid Fuels.Current edition approved April 15, 2009. Published April 2009. Originallyapproved in 1934. Last previous edition approved in 2004 as D 381 041.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orco
16、ntact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K.1*A Summary of Changes section appears at the end of this s
17、tandard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.method is not of itself correlative to induction-system deposits.The primary purpose of the test method, as applied to motorgasoline, is the measurement of the oxidation products
18、 formedin the sample prior to or during the comparatively mildconditions of the test procedure. Since many motor gasolinesare purposely blended with nonvolatile oils or additives, theheptane extraction step is necessary to remove these from theevaporation residue so that the deleterious material, gu
19、m, maybe determined. With respect to aviation turbine fuels, largequantities of gum are indicative of contamination of fuel byhigher boiling oils or particulate matter and generally reflectpoor handling practices in distribution downstream of therefinery.6. Apparatus6.1 Balance, capable of weighing
20、test specimens to thenearest 0.1 mg.6.2 Beakers, of 100-mL capacity, as illustrated in Fig. 1.Arrange the beakers in sets, the number in each set dependingupon the number of beaker wells in the evaporating bath. Markeach beaker in the set, including the tare beaker, with anidentifying number or lett
21、er.6.3 Cooling VesselA tightly covered vessel, such as adesiccator without desiccant, for cooling the beakers beforeweighing.NOTE 2The use of a desiccant could lead to erroneous results.6.4 Evaporation Bath (WarningIf a liquid-filled evapo-ration bath is used, care must be taken that the flash point
22、 of theliquid used is at least 30C higher than the highest bathtemperature expected.) Either a solid metal block bath or aliquid bath, electrically heated, and constructed in accordancewith the general principles shown in Fig. 1 may be used.(Although all dimensions are given in SI units, older baths
23、conforming to Test Method D 381 94, or earlier, are suitable.)The bath should have wells and jets for two or more beakers.The rate of flow from each outlet when fitted with the conicaladapters with 500 to 600 micron copper or stainless steelscreens should not differ from 1000 mL/s by more than 15 %.
24、Aliquid bath, if used, shall be filled to within 25 mm of the topwith a suitable liquid. Temperature shall be maintained bymeans of thermostatic controls or by refluxing liquids ofsuitable composition.6.5 Flow Indicator, as illustrated in Fig. 1, such as aflowmeter, capable of metering a flow of air
25、 or steam equiva-lent to 1000 mL/s for each outlet.NOTE 3Alternatively, a pressure gage may be used to meter the flowof air or steam equivalent to 1000 6 150 mL/s for each outlet.6.6 Sintered Glass Filtering Funnel, coarse porosity,150-mL capacity.6.7 SteamSupply by suitable means capable of deliver
26、ingto the bath inlet the required amount of steam at 232 to 246C.6.8 Temperature Sensor, liquid-in-glass thermometer con-forming to the requirements in the specification(s) for ASTM3C/IP73C, found in Specification E1, or another temperaturemeasuring device or system, or both, of at least equivalenta
27、ccuracy and precision over a temperature range from 5 to400C.6.9 Graduated Cylinders, with spout, capable of measuring50 6 0.5 mL.6.10 Handling Equipment, forceps (stainless steel, spadeended) or tongs (stainless steel) for use in handling the beakersand conical jets, as required by this test method
28、.7. Materials7.1 AirSupply of filtered air at a pressure not more than35 kPa.7.2 Gum SolventA mixture of equal volumes of tolueneand acetone.7.3 HeptaneMinimum purity of 99.7 %.7.4 SteamSupply of steam free of oily residue and at apressure not less than 35 kPa. (WarningIf a steam super-heater is use
29、d, there may be exposed hot surfaces on the steamsuperheater. Avoid contact with exposed skin by use ofprotective equipment as required.)8. Assembly of Air-Jet Apparatus8.1 Assemble the air-jet apparatus as shown in Fig. 1. Withthe apparatus at room temperature, adjust the air flow to give arate of
30、600 6 90 mL/s for the outlet under test. Check theremaining outlets for uniform air flow.NOTE 4A rate of 600 6 90 mL/s from each outlet, at roomtemperature and atmospheric pressure, will ensure delivery of 1000 6 150mL/s at the temperature of 155 6 5C for each outlet. It is recommendedto follow the
31、manufacturers instructions to verify total flow/s (600 mL/sair flow 3 number of outlets = total flow/s) and uniformity from eachoutlet.8.2 Apply heat to the evaporation bath (see 6.4) until thetemperature of the bath is between 160 and 165C. Introduceair into the apparatus at a rate indicated on the
32、 flow indicator(see 6.5) from the exercise carried out in 8.1. Measure thetemperature in each well with the temperature sensor (see 6.8)placed with the bulb or sensor tip resting on the bottom of theTABLE 1 Schedule of Test ConditionsSample TypeVaporizingMediumOperating TemperatureBath Test WellAvia
33、tion and motor gasoline air 160 to 165C 150 to 160CAviation turbine fuel steam 232 to 246C 229 to 235CFIG. 1 Apparatus for Determining Gum Content by JetEvaporationD381092beaker in the well. Do not use any well having a recordedtemperature outside the range from 150 to 160C.9. Assembly of Steam-Jet
34、Apparatus9.1 Assemble the steam-jet apparatus as shown in Fig. 1.(WarningThe sample and solvent vapors evaporated duringthe performance of this test procedure can be extremelyflammable or combustible and hazardous from the inhalationstandpoint. The evaporation bath must be provided with aneffective
35、exhaust hood to control such vapors and reduce therisk of thermal explosion.)9.2 To place the apparatus in operation, apply heat to thebath. When the temperature reaches 232C, slowly introducedry steam into the system until a rate of 1000 6 150 mL/s foreach outlet is reached (see 10.2). Regulate the
36、 temperature ofthe bath to a range from 232 to 246C to provide a welltemperature of 232 6 3C. Measure the temperature with thetemperature sensor, placed resting on the bottom of a beaker inone of the bath wells with the conical adapter in place. Anywell having a temperature that differs by more than
37、 3C from232C is not suitable for standard tests.10. Calibration and Standardization10.1 Air Flow:10.1.1 Verify or calibrate the air flow to ensure all outletsmeet the 600 6 90 mL/s air flow requirement as measured atroom temperature and atmospheric pressure. Refer to theinstrument manufacturer instr
38、uctions for specific guidance onperforming the air flow calibration procedure. Note the settingof the flow indicator device for use with air and use this settingfor subsequent tests.10.1.1.1 One way to calibrate the air flow is to use acalibrated flow indicator device, such as a flowmeter, separatef
39、rom the device specified in 6.5, to check the air flow rate ateach outlet directly at room temperature and atmosphericpressure. To obtain accurate results, ensure that the backpressure of the flowmeter is less than 1 kPa.10.1.1.2 Alternatively, another way to calibrate the air flowis to measure and
40、adjust as appropriate the total air flow rate(mL/s) supplied to the outlets. The total air flow rate equals theexpected air flow rate at each outlet times the number or outletpositions (for example, instrument has 5 positions and a totalair flow rate measurement of 3000 mL/s, indicating an ex-pected
41、 air flow rate of 600 mL/s at each outlet). Once verifyingthe total flow supplied to the outlets is at the appropriate rate,perform uniformity checks by comparing the relative air flowrates at each outlet position versus the requirements in 10.1.1.10.2 Steam Flow:10.2.1 Verify or calibrate the steam
42、 flow to ensure all outletsmeet the 1000 6 150 mL/s steam flow requirement. Refer tothe instrument manufacturer instructions for specific guidanceon performing the steam flow calibration procedure. Note thesetting of the flow indicator device for use with steam and usethis setting for subsequent tes
43、ts.10.2.1.1 One way to calibrate the steam flow, is to attach acopper tube to a steam outlet and extend the tube into a 2-Lgraduated cylinder that has been filled with crushed ice andwater that has been previously weighed. Exhaust the steam intothe cylinder for approximately 60 s. Adjust the positio
44、n of thecylinder so that the end of the copper tube is immersed in thewater to a depth of less than 50 mm to prevent excessive backpressure. After the appropriate time has elapsed, remove thecopper tube from the cylinder and weigh the cylinder. The gainin mass represents the amount of steam condense
45、d. Calculatethe steam rate (mL/s) as follows:R 5 M 2 m!1000/kt (1)where:R = steam rate (mL/s),M = mass of graduated cylinder with condensed steam, g,m = mass of graduated cylinder and ice, g,k = mass of 1000 mL of steam at 232C at atmosphericpressure = 0.434 g, andt = condensing time, s.11. Procedur
46、e11.1 Wash the beakers, including the tare, with the gumsolvent until free of gum. Rinse thoroughly with water andimmerse in a mildly alkaline or neutral pH laboratory detergentcleaning solution.11.1.1 The type of detergent and conditions for its use needto be established in each laboratory. The cri
47、terion for satisfac-tory cleaning shall be a matching of the quality of that obtainedwith chromic acid cleaning solutions on used beakers (freshchromic acid, 6-h soaking period, rinsing with distilled waterand drying). For this comparison visual appearance and massloss on heating the glassware under
48、 test conditions may beused. Detergent cleaning avoids the potential hazards andinconveniences related to handling corrosive chromic acidsolutions. The latter remains as the reference cleaning practiceand as such may function as an alternate to the preferredprocedure-cleaning with detergent solution
49、s.11.1.2 Remove the beakers from the cleaning solution bymeans of stainless steel forceps or tongs (see 6.10) and handleonly with forceps or tongs thereafter. Wash the beakersthoroughly, first with tap water and then with distilled water,and dry in an oven at 150C for at least 1 h. Cool the beakersfor at least2hinthecooling vessel placed in the vicinity of thebalance.11.2 Select the operating conditions, corresponding to theaviation and motor gasoline or aircraft turbine fuel under test,from the data given in Table 1. Heat the bath to the pre
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