1、Designation:D38109 Designation: D381 12Standard Test Method forGum Content in Fuels by Jet Evaporation1This standard is issued under the fixed designation D381; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. 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*1.1This1.1 This test method covers the determinati
3、on of the existent gum 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 oxygenates anddeposit control additivessee Note 7 for additional information) at the time of test.1.2 Provi
4、sions are made for the determination of the heptane insoluble portion of the residue of non-aviation fuels.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3.1 The accepted SI unit of pressure is the Pascal (Pa); the acce
5、pted SI unit for temperature is degrees Celsius.1.41.4 WARNINGMercury has been designated by many regulatory agencies as a hazardous material that can cause centralnervous system, kidney and liver damage. Mercury, or its vapor, may be hazardous to health and corrosive to materials. Cautionshould be
6、taken when handling mercury and mercury containing products. See the applicable product Material Safety Data Sheet(MSDS) for details and EPAs websitehttp:/www.epa.gov/mercury/faq.htmfor additional information. Users should be awarethat selling mercury and/or mercury containing products into your sta
7、te or country may be prohibited by law.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylim
8、itations prior to use. For specific warning statements, see 6.4, 7.4, and 9.1.2. Referenced Documents2.1 ASTM Standards:2D1655 Specification for Aviation Turbine FuelsD4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsE1 Specification for ASTM Liquid-in-Glass ThermometersE29 Pract
9、ice for Using Significant Digits in Test Data to Determine Conformance with Specifications2.2 Energy Institute Standard:3IP Standard Methods for Analysis and Testing of Petroleum ProductsIP 540 Determination of the existent gum content of aviation turbine fuel jet evaporation method3. Terminology3.1
10、 Definitions of Terms Specific to This Standard:3.1.1 existent gumexistent gum, nthe evaporation residue of aviation fuels, without any further treatment.3.2 For non-aviation fuels, the following definitions apply.3.3 solvent washed gum contentsolvent washed gum content, nthe residue remaining when
11、the evaporation residue (see 3.4)has been washed with heptane and the washings discarded.3.3.1 DiscussionFor motor gasoline or non-aviation gasoline, solvent washed gum content was previously referred to asexistent gum.3.4 unwashed gum contentunwashed gum content, nthe evaporation residue of the pro
12、duct or component under test, withoutany further treatment.1This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.14 onStability and Cleanliness of Liquid Fuels.Current edition approved April 15, 200
13、9. Published April 2009. Originally approved in 1934. Last previous edition approved in 2004 as D381 041. DOI:10.1520/D0381-09.Current edition approvedApril 15, 2012. Published May 2012. Originally approved in 1934. Last previous edition approved in 2009 as D38109. DOI: 10.1520/D0381-12.2For referen
14、ced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR
15、, U.K.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult pr
16、ior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1
17、9428-2959, United States.4. Summary of Test Method4.1When4.1 When testing either aviation or motor gasoline, a 50 6 0.5 mL quantity of fuel is evaporated under controlledconditions of temperature and flow of air (see Table 1). When testing aviation turbine fuel, a 50 6 0.5 mL quantity of fuel isevap
18、orated under controlled conditions of temperature and flow of steam (see Table 1). For aviation gasoline and aviation turbinefuel, the resulting residue is weighed and reported as milligrams per 100 mL. For motor gasoline, the residue is weighed beforeand after extracting with heptane and the result
19、s reported as milligrams per 100 mL.NOTE 1Specification D1655 allows the existent gum of aviation turbine fuels to be determined by either Test Method D381 or IP 540, with TestMethod D381 identified as the referee test method. Test Method D381 specifically requires the use of steam as the evaporatin
20、g medium for aviation turbinefuels, whereas IP 540 allows either air or steam as the evaporating medium for aviation turbine fuels.5. Significance and Use5.1 The true significance of this test method for determining gum in motor gasoline is not firmly established. It has been provedthat high gum can
21、 cause induction-system deposits and sticking of intake valves, and in most instances, it can be assumed that lowgum will ensure absence of induction-system difficulties. The user should, however, realize that the test method is not of itselfcorrelative to induction-system deposits. The primary purp
22、ose of the test method, as applied to motor gasoline, is the measurementof the oxidation products formed in the sample prior to or during the comparatively mild conditions of the test procedure. Sincemany motor gasolines are purposely blended with nonvolatile oils or additives, the heptane extractio
23、n step is necessary to removethese from the evaporation residue so that the deleterious material, gum, may be determined. With respect to aviation turbine fuels,large quantities of gum are indicative of contamination of fuel by higher boiling oils or particulate matter and generally reflect poorhand
24、ling practices in distribution downstream of the refinery.6. Apparatus6.1 Balance, capable of weighing test specimens to the nearest 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 depending uponthe number of beaker wells in the e
25、vaporating bath. Mark each beaker in the set, including the tare beaker, with an identifyingnumber or letter.6.3 Cooling VesselA tightly covered vessel, such as a desiccator without desiccant, for cooling the beakers before weighing.NOTE 2The use of a desiccant could lead to erroneous results.6.4 Ev
26、aporation Bath (WarningIf a liquid-filled evaporation bath is used, care must be taken that the flash point of the liquidused is at least 30C higher than the highest bath temperature expected.) Either a solid metal block bath or a liquid bath, electricallyheated, and constructed in accordance with t
27、he general principles shown in Fig. 1 may be used. (Although all dimensions are givenin SI units, older baths conforming to Test Method D381 94, or earlier, are suitable.) The bath should have wells and jets fortwo or more beakers. The rate of flow from each outlet when fitted with the conical adapt
28、ers with 500 to 600 micron copper orstainless steel screens should not differ from 1000 mL/s by more than 15 %. A liquid bath, if used, shall be filled to within 25 mmof the top with a suitable liquid. Temperature shall be maintained by means of thermostatic controls or by refluxing liquids ofsuitab
29、le composition.6.5 Flow Indicator, as illustrated in Fig. 1, such as a flowmeter, capable of metering a flow of air or steam equivalent to 1000mL/s for each outlet.NOTE 3Alternatively, a pressure gage may be used to meter the flow of air or steam equivalent to 1000 6 150 mL/s for each outlet.6.6 Sin
30、tered Glass Filtering Funnel, coarse porosity, 150-mL capacity.6.7 SteamSupply by suitable means capable of delivering to the bath inlet the required amount of steam at 232 to 246C.6.8 Temperature Sensor, liquid-in-glass thermometer conforming to the requirements in the specification(s) for ASTM3C/I
31、P73C, found in Specification E1, or another temperature measuring device or system, or both, of at least equivalent accuracyand precision over a temperature range from 5 to 400C.6.9 Graduated Cylinders, with spout, capable of measuring 50 6 0.5 mL.6.10 Handling Equipment, forceps (stainless steel, s
32、pade ended) or tongs (stainless steel) for use in handling the beakers andconical jets, as required by this test method.7. Materials7.1 AirSupply of filtered air at a pressure not more than 35 kPa.TABLE 1 Schedule of Test ConditionsSample TypeVaporizingMediumOperating TemperatureBath Test WellAviati
33、on and motor gasoline air 160 to 165C 150 to 160CAviation turbine fuel steam 232 to 246C 229 to 235CD381 1227.2 Gum SolventA mixture of equal volumes of toluene and acetone.7.3 HeptaneMinimum purity of 99.7 %.7.4 SteamSupply of steam free of oily residue and at a pressure not less than 35 kPa. (Warn
34、ingIf a steam superheater isused, there may be exposed hot surfaces on the steam superheater.Avoid contact with exposed skin by use of protective equipmentas required.)8. Assembly of Air-Jet Apparatus8.1 Assemble the air-jet apparatus as shown in Fig. 1. With the apparatus at room temperature, adjus
35、t the air flow to give a rateof 600 6 90 mL/s for the outlet under test. Check the remaining outlets for uniform air flow.NOTE 4A rate of 600 6 90 mL/s from each outlet, at room temperature and atmospheric pressure, will ensure delivery of 1000 6 150 mL/s at thetemperature of 155 6 5C for each outle
36、t. It is recommended to follow the manufacturers instructions to verify total flow/s (600 mL/s air flow 3 numberof outlets = total flow/s) and uniformity from each outlet.8.2 Apply heat to the evaporation bath (see 6.4) until the temperature of the bath is between 160 and 165C. Introduce air intothe
37、 apparatus at a rate indicated on the flow indicator (see 6.5) from the exercise carried out in 8.1. Measure the temperature ineach well with the temperature sensor (see 6.8) placed with the bulb or sensor tip resting on the bottom of the beaker in the well.Do not use any well having a recorded temp
38、erature outside the range from 150 to 160C.9. Assembly of Steam-Jet Apparatus9.1 Assemble the steam-jet apparatus as shown in Fig. 1. (WarningThe sample and solvent vapors evaporated during theperformance of this test procedure can be extremely flammable or combustible and hazardous from the inhalat
39、ion standpoint. Theevaporation bath must be provided with an effective exhaust hood to control such vapors and reduce the risk of thermal explosion.)9.2 To place the apparatus in operation, apply heat to the bath. When the temperature reaches 232C, slowly introduce dry steaminto the system until a r
40、ate of 1000 6 150 mL/s for each outlet is reached (see 10.2). Regulate the temperature of the bath to arange from 232 to 246C to provide a well temperature of 232 6 3C. Measure the temperature with the temperature sensor, placedresting on the bottom of a beaker in one of the bath wells with the coni
41、cal adapter in place. Any well having a temperature thatdiffers by more than 3C from 232C 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 outlets meet the 600 6 90 mL/s air flow requirement as measured at roomt
42、emperature and atmospheric pressure. Refer to the instrument manufacturer instructions for specific guidance on performing theair flow calibration procedure. Note the setting of the flow indicator device for use with air and use this setting for subsequent tests.10.1.1.1 One way to calibrate the air
43、 flow is to use a calibrated flow indicator device, such as a flowmeter, separate from thedevice specified in 6.5, to check the air flow rate at each outlet directly at room temperature and atmospheric pressure. To obtainaccurate results, ensure that the back pressure of the flowmeter is less than 1
44、 kPa.10.1.1.2 Alternatively, another way to calibrate the air flow is to measure and adjust as appropriate the total air flow rate (mL/s)supplied to the outlets. The total air flow rate equals the expected air flow rate at each outlet times the number or outlet positions(for example, instrument has
45、5 positions and a total air flow rate measurement of 3000 mL/s, indicating an expected air flow rateof 600 mL/s at each outlet). Once verifying the total flow supplied to the outlets is at the appropriate rate, perform uniformitychecks by comparing the relative air flow rates at each outlet position
46、 versus the requirements in 10.1.1.10.2 Steam Flow:FIG. 1 Apparatus for Determining Gum Content by JetEvaporationD381 12310.2.1 Verify or calibrate the steam flow to ensure all outlets meet the 1000 6 150 mL/s steam flow requirement. Refer to theinstrument manufacturer instructions for specific guid
47、ance on performing the steam flow calibration procedure. Note the settingof the flow indicator device for use with steam and use this setting for subsequent tests.10.2.1.1 One way to calibrate the steam flow, is to attach a copper tube to a steam outlet and extend the tube into a 2-Lgraduatedcylinde
48、r that has been filled with crushed ice and water that has been previously weighed. Exhaust the steam into the cylinder forapproximately 60 s. Adjust the position of the cylinder so that the end of the copper tube is immersed in the water to a depth ofless than 50 mm to prevent excessive back pressu
49、re. After the appropriate time has elapsed, remove the copper tube from thecylinder and weigh the cylinder. The gain in mass represents the amount of steam condensed. Calculate the steam rate (mL/s) asfollows:R 5 M 2 m!1000/kt (1)D0381-12_1where: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 atmospheric pressure = 0.434 g, andt = condensing time, s.11. Procedure11.1 Wash the beakers, including the tare, with the gum solvent
