1、Designation: D7872 13Standard Test Method forDetermining the Concentration of Pipeline Drag ReducerAdditive in Aviation Turbine Fuels1This standard is issued under the fixed designation D7872; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the measurement of highmolecular weight polymers, in particular pipeline
3、 drag reduceradditive (DRA), in aviation turbine fuels with a 72 g/L lowerdetection limit. The method cannot differentiate between dif-ferent polymers types. Thus, any non-DRA high molecularweight polymer will cause a positive measurement bias.Further investigation is required to confirm the polymer
4、detected is DRA.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 WarningMercury has been designated by many regu-latory agencies as a hazardous material that can cause centralnervous system, kidney and liver damage. Mercu
5、ry, or itsvapor, may be hazardous to health and corrosive to materials.Caution should be taken when handling mercury and mercurycontaining products. See the applicable product MaterialSafety Data Sheet (MSDS) for details and EPAs website http:/www.epa.gov/mercury/faq.htm for additional infor-mation.
6、 Users should be aware that selling mercury and/ormercury containing products into your state or country may beprohibited by law.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
7、 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum Products2.
8、2 Other Reference:CRC Report No. 642 Investigation of Pipeline Drag Reduc-ers in Aviation Turbine Fuels3. Terminology3.1 Definitions:3.1.1 bumping, vviolent boiling which displaces liquidinto the distillation flask.3.1.2 drag reducing additive (DRA), na material com-prised of very high molecular wei
9、ght hydrocarbon polymersthat is soluble in petroleum products and used to reduce thefluid friction during pipeline transportation.3.1.3 rotary evaporation, na distillation process utilizingheat, reduced pressure and a rotating flask which evaporatesfluid to reduce the volume of a sample of material.
10、3.1.3.1 DiscussionThe apparatus, consisting of a round-bottomed flask in a heated bath, is operated under vacuum(reduced pressure) to lower the boiling point of the fluid, andthe rotational motion accelerates evaporation of the liquid bycreating additional surface area of the fluid being distilled o
11、ff.3.1.4 sheared DRA, nthe very long hydrocarbon polymersof drag reducing agent that have been shortened by severephysical processes such that the resulting material is no longereffective at reducing fluid friction.3.1.4.1 DiscussionSevere physical and mechanical pro-cesses include large pressure ch
12、anges which can occur atcontrol valves, pumps, meters, reductions in pipe diameterwhich affect fluid velocity, and ultrasonication in a laboratoryprocess, resulting in shorter polymeric chains which are stillvery large compared to the fuel molecules and are non-distillable.3.1.5 total exclusion, npo
13、lymers larger than the pore sizecannot enter the pores and elute together as the first peak in thechromatogram.3.2 Abbreviations:3.2.1 DRAdrag reducing additive3.2.2 GPCgel permeation chromatography3.2.3 RIrefractive index1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum
14、Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.J0.01 on Jet Fuel Specifications.Current edition approved June 15, 2013. Published September 2013. DOI:10.1520/D7872-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cust
15、omer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.4 THFtetrahydrofuran4. Summary o
16、f Test Method4.1 The method employs a rotary evaporator (also called arotovap) to concentrate the DRA in a base sample followed byGPC to separate and quantify the DRA from the remaining jetfuel. Rotovaping is a rapid vacuum distillation process used toreduce the volume of jet fuel which effectively
17、increases therelative DRA concentration. The GPC method uses heptane orTHF as the mobile phase, a single separation column andrefractive index detection. The separation column containsparticles with pore sizes that totally exclude sheared andunsheared DRA polymers to give a sharp chromatographicDRA
18、peak.4.2 An approximate 400 g sample of jet fuel is concentratedthrough rotary evaporation and analyzed by GPC. The DRAconcentration is quantified by integrating the area under theDRA peak. Comparing this area to a calibration curve allows adetermination of the weight fraction of the DRA component i
19、nthe concentrated jet fuel. The original concentration is obtainedby correcting for the concentrating in the rotary evaporation ofthe jet fuel. The detector is calibrated using standards ofsheared DRA in jet fuel in the low mg/L concentration range.5. Significance and Use5.1 DRA is frequently added
20、into multiproduct pipelines toincrease throughput or reduce energy requirements of fuelmovement. Although these additives are not used in jet fuel,contamination can occur from other products if proper batchingguidelines are not followed or by other cases of human error.CRC Report No. 642 reviewed th
21、e impact of DRA on jet fuelfit-for-purpose performance and concluded that the fuel sprayangle and atomization capability of several engine-type fuelnozzles can be adversely affected impacting high altituderelight performance at elevated concentrations. A method thataccurately quantifies the amount o
22、f DRA in jet fuel can beuseful in confirming the absence of significant contaminationto protect the safety of aviation operations. This test method isdesigned to measure down to sub-100 g/L levels of DRA inaviation fuel.6. Interferences6.1 This test method has no particular specificity for DRAand wi
23、ll also measure any other high molecular weightcompounds present in the sample making it susceptible tointerferences. However, no high molecular weight polymersare approved for blending into aviation fuels. Stadis 450 has alow molecular weight polymer and was checked. No interfer-ence was found. The
24、 presence of non-DRA high molecularweight polymers would create a positive measurement bias.However, detection sensitivity of the non-DRA high molecularweight polymers may not be the same because of polymer typedifferences. Thus, non-DRA high molecular weight polymersshould not be quantified by this
25、 test method.7. Apparatus7.1 Vacuum source, such as a vacuum pump capable ofreducing the pressure in a rotary evaporator to 6.77 kPa (28 in.of mercury below atmospheric pressure).7.2 Rotary evaporator, equipped with a silicone oil heatingbath that can accommodate flasks capable of holding 400 g ofje
26、t fuel. A bump trap may be connected to the evaporationflask. Any silicone oil bath capable of reaching 180C issuitable. There are a variety of high temperature silicone bathoils that may be used and are commercially available. Watermay be used to cool the rotovap condenser. Details of therotovap ar
27、e described in Table 1.NOTE 1Bumping can cause loss of polymer from the flask that wouldcreate a lower than actual detection value.7.3 Gel permeation chromatography system, described inTable 2. The method includes flexibility in the selection ofGPC hardware and conditions; however, a refractive inde
28、xdetector is required.7.4 Any GPC apparatus may be used, provided the RIdetector response to the DRA peak has a signal to noise (S/N) 10 for a 50 g/L DRA in jet fuel sample after rotaryevaporation (this translates into 10 mg/L if rotary evaporationprovided a reduction of 400 g to 2 g for a jet fuel
29、samplecontaining 50 g/L DRA).7.5 To achieve sub 100 g/L DRA detection, a column thatexhibits total exclusion of the sheared DRA is required. Totalexclusion leads to sharper elution peaks providing easierdetection. In addition, polymers are susceptible to shearingwhile passing through a GPC column. C
30、olumns packed withlarge particle size stationary phase avoid shearing, 5 or 10 mparticle sizes are recommended.8. Reagents and Materials8.1 All chemicals are American Chemical Society gradechemicals or better unless specified otherwise.8.2 Drag reducing additive, available from appropriate ad-ditive
31、 supplier in “sheared” form for use in preparing stan-dards.9. Sampling9.1 Fuel samples are typically drawn from pipelines. Con-sult Practice D4057 for guidance on proper sampling proce-dures. Consult Practice D4177 for guidance on auto sampling.10. Preparation of Apparatus10.1 The GPC should be equ
32、ilibrated for 1 h and the columntemperature stabilized to the temperature of the analysis priorto analyzing samples.11. Calibration and Standardization11.1 Prepare standards of sheared DRA in jet fuel bydilution of a concentrated stock solution supplied by anappropriate additive supplier in the rang
33、e of 0 to 100 mg/L.TABLE 1 Rotovap ConditionsPressure 3.1 kPa to 6.5 kPa (28 to 29 in. Hg below atmosphericpressure)Temperature 120 to 180CApproximate time 1 to3h(depending on vacuum pressure andtemperature)D7872 132Base jet fuel should be free of DRA and other high molecularweight polymer contamina
34、tion. For the development of themethod a 1 wt% concentrate of sheared FLO XS DRA (10000mg/kg, 8010 mg/L) in jet fuel was obtained from BakerHughes for making the calibration samples. The concentratemay also be provided in diesel fuel.11.2 Prepare a 200 mg/L stock calibration sample by quan-titativel
35、y blending 4.0 mL of the 8010 mg/L concentrate with156.2 mL jet fuel. From this, make a series of 100 mLcalibration samples in the range of 2.0 to 100 mg/L, by placingvolumes of 200 mg/L stock calibration sample, given in Table3, into the required number of 100 mL capacity volumetricflasks and makin
36、g them up to 100 mL with jet fuel.12. Procedure12.1 If non-sheared DRA samples were provided or toensure the DRAin jet fuel is sheared, the sample may be placedin an ultrasonicator or mechanically sheared with a homog-enizer. Details on procedures for shearing can be provided bythe DRA supplier.12.2
37、 Accurately weigh approximately 400 g of jet fuel to0.1 g in a tared 1 L round bottom flask (W1). Concentrate thissample to between2gto10gonarotary evaporator andaccurately weigh the residue to 0.1 g (W2).NOTE 2Oil from the oil bath should be removed from the outsidesurface of the round bottom flask
38、 with volatile solvent and allowed to dryto ensure accurate weighting of the flask with the jet fuel concentrate.NOTE 3Avoid the use of silicone vacuum grease on the round bottomflask fitting.12.3 Transfer some of the concentrated sample to a vialfrom which a syringe aliquot may be drawn (or into a
39、suitableGPC auto sampler vial). The entire sample does not need to betransferred and the remaining may be saved or discarded.12.4 GPC operation parameters are summarized in Table 2.The one hour equilibration step (10.1) is done to ensure thebaseline is flat prior to sample injection. 100 L of standa
40、rdsand concentrated sample are injected in the GPC apparatus andthe output is recorded on an electronic data collection system.13. Calculation or Interpretation of Results13.1 The chromatogram peak area corresponding to theDRA signal in the 3 to 4 min region is integrated. An externalcalibration cur
41、ve plotting integrated area of DRA standardsverses the mg/L of the standards is used to determine mg/LDRAin sample. Ensure that the correct standard concentrationsare entered into the chromatography data system calibrationstable and construct a calibration curve for sheared DRA. SeeFig. 2 for an exa
42、mple.13.2 The DRA concentration in the concentrated jet fuelsample is determined by integrating the area of the DRA peakNOTE 1Chromatogram of a concentrated jet fuel sample originally containing 50 g/L of sheared DRA acquired using a GPC apparatus describedin Table 2 (GPC column, 10 m particles with
43、 500 pore size, heptane mobile phase). Noise is the height of the high frequency peak to peak displacementtaken near the peak through a range which is at least the width of the base of the DRA peak. Signal is the peak height. Chromatogram example exhibitsa DRA signal that satisfies the S/N 10.FIG. 1
44、 Signal to Noise ExampleTABLE 2 GPC Components and Operation ParametersColumn 5 or 10 m particle size; between 50 (5 nm) and104 (1000 nm) pore sizeLength: 300 mmID: 7.5 mmTemperature: 20 to 40CFlow Rate: 1.5 mL/minMobile phase THF or HeptaneVolume injected 100 LEquilibration time 1 h (prior to injec
45、tions)Detector RITABLE 3 DRA in Jet Fuel Calibration StandardsAVolume (mL) of 200 mg/L stockcalibration sample added to100 mL capacity volumetric flasks2 mg/L calibration sample (CS1) 1.04 mg/L calibration sample (CS2) 2.010 mg/L calibration sample (CS3) 5.020 mg/L calibration sample (CS4) 10.0100 m
46、g/L calibration sample (CS5) 50.0ARecord data to the same decimal place indicated in Table 3. Use DRA-free jetfuel for a zero concentration calibration sample.D7872 133in the concentrated fuel and using the external calibration curveto determine the associated DRA mg/L level (Fig. 3).13.3 The level
47、of DRAin the test specimen is determined bymultiplying the concentration (in mg/L) of DRAdetermined byGPC in the concentrated fuel by the dilution factor for thesample which is the ratio of the weight of fuel after and beforeconcentrating.13.4 Calculate the concentration of DRA in jet fuel (inmg/L)
48、as follows:Concentration of DRA in jet fuel =calculated mg/L DRA in jet fuel concentrate!3(W2W1) (1)where:W1 = weight of jet fuel in a tared 1 L round bottom flaskprior to rotovaping, andW2 = weight of residue after rotovaping (W2).13.5 Eq 1 reports the level in mg/L. Multiply result by 1000to repor
49、t g/L level of DRA in finished fuel.14. Report14.1 Report the concentration of drag reducing additive(DRA) in the fuel sample, in units of g/L to the nearest wholeunit, and reference this test method. If the result is less than 72g/L, report “less than 72 g/L”.15. Precision and Bias15.1 The precision of this test method is as follows:Repeatability = 0.01793 (X + 1117.6082) g/LReproducibility = 0.03014 (X + 1117.6082) g/L(X is the average of results being compared)15.1.1 Precision was determined using DP22 software oninterlaboratory re
