1、Designation: D5762 18Standard Test Method forNitrogen in Liquid Hydrocarbons, Petroleum and PetroleumProducts by Boat-Inlet Chemiluminescence1This standard is issued under the fixed designation D5762; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、case of 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. Scope*1.1 This test method covers the determination of nitrogen inliquid hydrocarbons, including
3、petroleum process streams andlubricating oils in the concentration range from 40 gg to10 000 gg nitrogen. For light hydrocarbons containing lessthan 100 gg nitrogen, Test Method D4629 can be moreappropriate.1.2 The values stated in SI units are to be regarded asstandard. No other units of measuremen
4、t are included in thisstandard.1.3 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, health, and environmental practices and deter-mine the applicability of regu
5、latory limitations prior to use.Specific warning statements are given in Section 6, 7.1, 8.2,and 8.2.2.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of Internati
6、onal Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleu
7、m ProductsD4629 Test Method for Trace Nitrogen in Liquid Hydrocar-bons by Syringe/Inlet Oxidative Combustion and Chemi-luminescence DetectionD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System Performance3. Summary of Test
8、 Method3.1 A hydrocarbon sample is placed on a sample boat atroom temperature. The sample and boat are advanced into ahigh-temperature combustion tube where the nitrogen is oxi-dized to nitric oxide (NO) in an oxygen atmosphere. The NOcontacts ozone and is converted to excited nitrogen dioxide(NO2).
9、 The light emitted as the excited NO2decays is detectedby a photomultiplier tube, and the resulting signal is a measureof the nitrogen contained in the sample.4. Significance and Use4.1 Many nitrogen compounds can contaminate refinerycatalysts. They tend to be the most difficult class of compoundsto
10、 hydrogenate, so the nitrogen content remaining in theproduct of a hydrotreator is a measure of the effectiveness ofthe hydrotreating process. In lubricating oils the concentrationof nitrogen is a measure of the presence of nitrogen containingadditives. This test method is intended for use in plant
11、controland in research.5. Apparatus5.1 Boat Inlet System, capable of being sealed to the inlet ofthe combustion tube and swept with inert gas. The boats arefabricated from platinum or quartz. To aid quantitative liquidinjection, it is recommended to add a small piece of quartzwool or suitable equiva
12、lent (see 6.8) to the boat. The boat drivemechanism should be able to fully insert the boat into thefurnace tube inlet section. A drive mechanism that advancesand withdraws the sample boat into and out of the furnace at acontrolled and repeatable rate is required.5.2 Chemiluminescence Detector, capa
13、ble of measuringlight emitted from the reaction between nitric oxide and ozone,and containing a variable attenuation amplifier, integrator, andreadout.NOTE 1Detectors designed to maintain the chemiluminescence reac-tion cell at reduced pressure are acceptable for use and were included inthe instrume
14、nts used to determine the precision of this test method.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.03 on Elemental Analysis.Current edition approved April 1, 2018. Published
15、April 2018. Originallyapproved in 1995. Last previous edition approved in 2017 as D5762 17. DOI:10.1520/D5762-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the
16、 standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internati
17、onally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.15.3 Combustion Tube, fabricated from quartz. The inl
18、et endof the tube shall be large enough to accept the sample boat andto have side arms for introduction of oxygen and inert gas. Theconstruction is such that the carrier gases sweep the inlet zonetransporting all of the volatilized sample into a high-temperature oxidation zone. The oxidation section
19、 should belarge enough to ensure complete oxidation of the sample.5.4 Drier Tube, for the removal of water vapor. The reactionproducts include water vapor that shall be eliminated prior tomeasurement by the detector. This can be accomplished with amagnesium perchlorate, Mg(ClO4)2, scrubber, a membra
20、nedrying tube permeation drier, or a chilled dehumidifier assem-bly.5.5 Furnace, Electric, held at a temperature sufficient topyrolyze all of the sample and oxidize the nitrogen to NO. Thefollowing furnace designs may be used.All furnace assembliesinclude a method for gas flow control, such as needl
21、e valves,flow restrictors or mass flow controllers. Furnaces that areoperated at temperatures below 1050 C shall be capable ofswitching to 100 % oxygen carrier gas flow after the boat hasbeen fully extended into the furnace.5.5.1 Single-zone tube furnace with temperature controllercapable of maintai
22、ning a stable furnace temperature of 1100 C6 25 C.5.5.2 Two-zone tube furnace with temperature controllerscapable of maintaining the temperature of each furnace zoneindependently from 950 C to 1050 C (see 5.5). Or two-zonetube furnace equipped with the ability to change to a pureoxygen carrier gas f
23、low after the boat is fully extended in to thefurnace and temperature controllers capable of maintaining thetemperature of each furnace zone independently to 950 C.5.6 Microlitre Syringe, of 5 Lor 10 Lcapacity, capable ofaccurately delivering microlitre quantities.5.7 Ozone Generator, to supply ozon
24、e to the detectorreaction cell.5.8 Recorder (Optional), for display of chemiluminescencedetector signal.6. Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of
25、 the Commit-tee on Analytical Reagents of the American Chemical Societywhere such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 Acridine,
26、C13H9N, molecular weight 179.21, 7.82 % bymass nitrogen. (WarningIrritant.)6.3 Oxidation Catalyst: Cupric Oxide Wire, CuO, or Plati-num Catalyst, PtAl2O3, as recommended by the instrumentmanufacturer.6.4 Inert GasArgon or Helium only, high-purity grade(that is, chromatographic or zero grade), 99.998
27、 % minimumpurity, 5 ppm maximum moisture.6.5 Anhydrous Magnesium Perchlorate, Mg(ClO4)2, fordrying products of combustion (if permeation drier or chilleddrier is not used). (WarningStrong oxidizer, irritant.)6.6 Nitrogen Stock Solution, 500 ng nitrogen/L. See 6.6.1.6.6.1 Calibration standards from c
28、ommercial sources maybe used if they conform to the requirements of the test method.6.6.2 Volumetric PreparationAccurately weigh (to thenearest 0.1 mg) approximately 0.64 g of acridine into a tared100 mLvolumetric flask.Add xylene to dissolve, then dilute tovolume with xylene. Calculate the nitrogen
29、 content of the stocksolution to the nearest milligram of nitrogen per litre. Thisstock can be further diluted to desired nitrogen concentrations.(WarningRemake standard solutions on a regular basisdepending upon frequency of use and age. Typically, standardshave a useful life of approximately three
30、 months.)6.6.3 Gravimetric PreparationAccurately weigh (to thenearest 0.1 mg) approximately 0.74 g of acridine into a taredcontainer. Add xylene to dissolve, then add xylene to anapproximate weight of 100 g with xylene. Calculate the nitro-gen content of the stock solution to the nearest milligram o
31、fnitrogen per kilogram. Convert the concentration to milligramsof nitrogen per litre by multiplying by the density of xylene.This stock can be further diluted to desired nitrogen concen-trations. (WarningRemake standard solutions on a regularbasis depending upon frequency of use and age. Typically,s
32、tandards have a useful life of approximately three months.)6.7 Oxygen, high-purity grade (that is, chromatographic orzero grade), 99.75 % minimum purity, 5 ppm maximummoisture, dried over molecular sieves. (WarningVigorouslyaccelerates combustion.)6.8 Quartz Wool (optional), or other suitable absorb
33、entmaterial that is stable and capable of withstanding temperaturesinside the furnace (see Note 2).NOTE 2Materials meeting the requirements in 6.8 are recommendedto be used in sample boats to provide a more uniform injection of thesample into the boat by wicking any remaining drops of the sample fro
34、mthe tip of the syringe needle prior to introduction of the sample into thefurnace. Consult instrument manufacturer recommendations for furtherguidance.6.9 Silver Wool, as recommended by the instrument manu-facturer.6.10 Xylene. (WarningFlammable, health hazard.)6.11 Calibration Check Sample(s)porti
35、ons of one or moreliquid petroleum or product standards of known nitrogencontent and not used in the generation of the calibration curve.A calibration check sample or samples shall be used to verifythe validity of the calibration curve as described in Section 10.6.12 Quality Control (QC) Sample(s)pr
36、eferably portionsof one or more liquid petroleum materials that are stable andrepresentative of the samples of interest. These QC samples3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the
37、 American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D5762 182can be used to verify that the testing process is in statisticalcontrol
38、 as described in Section 10.7. Sampling7.1 Obtain a test sample in accordance with Practice D4057or D4177.(WarningSamples that are collected at tempera-tures below room temperature can undergo expansion atlaboratory temperatures and rupture the container. For suchsamples, do not fill the container t
39、o the top. Leave sufficient airspace above the sample to allow room for expansion.)(WarningTo minimize loss of volatile components, whichcan be present in some test samples, do not uncover any longerthan necessary. Test samples should be analyzed as soon aspossible after taking from bulk supplies to
40、 prevent loss ofnitrogen or contamination due to exposure or contact withsample container.)7.2 If the test sample is not used immediately, then thor-oughly mix it in its container prior to taking a test specimen.Some test samples require heating in order to thoroughlyhomogenize.8. Preparation of App
41、aratus8.1 Assemble apparatus in accordance with the manufactur-ers instructions.8.2 Adjust the oxygen flow for the ozone generator inaccordance with the manufacturers instructions. Adjust thecombustion tube gas flows and the pyrolysis temperature to therecommended operating conditions using the foll
42、owing guide-lines for each furnace type. (WarningOzone is extremelytoxic. Make sure that appropriate steps are taken to preventdischarge of ozone within the laboratory work area.)8.2.1 For the single-zone furnace without the ability tochange to a pure oxygen carrier gas flow after the boat has beenf
43、ully extended into the furnace, adjust the combustion tube gasflows to the following values: pyrolysis oxygen, 360 mLmin6 36 mLmin; inlet oxygen, 60 mLmin 6 6 mLmin; andinert carrier inlet, 155 mLmin 6 15 mLmin. Other gas flowsmay be used if it can be shown that precision and bias are notdegraded. S
44、et the furnace temperature to 1100 C 6 25 C.Adjust the boat drive mechanism to obtain a drive rate of150 mmmin 6 10 mmmin. Refer to the manufacturersinstructions for descriptions of these settings.8.2.2 For the two-zone furnace without the ability to changeto a pure oxygen carrier gas flow after the
45、 boat has been fullyextended into the furnace, adjust the combustion tube gas flowsto the following values: combustion oxygen, 165 mLmin616 mLmin; inlet inert carrier, 85 mLmin 6 9 mLmin; andboat inert carrier, 50 mLmin 6 5 mLmin. Other gas flowsmay be used if it can be shown that precision and bias
46、 are notdegraded. Set the inlet furnace temperature to 1050 C 625 C, and the outlet furnace temperature to 925 C 6 25 C.Adjust the boat drive mechanism to obtain a drive rate of150 mmmin 6 10 mmmin (boat speed number 4). Refer tothe manufacturers instructions for the description of thesesettings. (W
47、arningHigh temperature is employed in this testmethod. Use flammable materials with care near the pyrolysisfurnace.)8.2.3 For the two-zone furnace with the ability to change toa pure oxygen carrier gas flow after the boat has been fullyextended in to the furnace, adjust the combustion tube gasflows
48、to the following values: main oxygen, 400 mLmin 640 mLmin; inlet argon carrier, 0.4 Lmin 6 0.04 Lmin, andinlet oxygen carrier, 0.4 Lmin 6 0.04 Lmin. Other gas flowsmay be used if it can be shown that precision and bias are notdegraded. Set the inlet furnace temperature to 600 C 6 25 C,and the outlet
49、 (catalyst) temperature to 950 C 6 25 C. Set theautomatic boat control as follows: 1 Fuc FWD 125 speed 10time 30, 2 Fuc 285 speed 05 time 30, 5 Fuc time 30, 6 Fuc time90, A Fuc time 60. Refer to manufacturers instructions for adescription of these settings.8.3 Insert boat into furnace for a minimum of 2 min toremove any residual nitrogen species.9. Calibration and Standardization9.1 Prepare calibration standards containing 1 ng, 5 ng,10 ng, 50 ng, and 100 ng nitrogenL in xylene by volumetricor gravimetric diluti
