1、Designation: D5762 11Standard Test Method forNitrogen in Petroleum and Petroleum Products by Boat-InletChemiluminescence1This standard is issued under the fixed designation D5762; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 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 petroleum process str
3、eams andlubricating oils in the concentration range from 40 to 10 000g/g nitrogen. For light hydrocarbons containing less than 100g/g nitrogen, Test Method D4629 can be more appropriate.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thi
4、sstandard.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 and health practices and determine the applica-bility of regulatory limitations prior to use. Spec
5、ific warningstatements are given in Section 6, 7.1, 8.2, and 8.2.2.2. Referenced Documents2.1 ASTM Standards:2D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD4629 Test Method for Trace Nitrogen in Liquid Pe
6、troleumHydrocarbons by Syringe/Inlet Oxidative Combustion andChemiluminescence DetectionD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System Performance3. Summary of Test Method3.1 A hydrocarbon sample is placed on a sample
7、 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). The light emitted as the excited NO2decays is detect
8、edby 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 hydrogenate, so the nitrogen content remaining in th
9、eproduct 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 controland in research.5. Apparatus5.1 Boat Inlet Sys
10、tem, 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 equivalent (see 6.8) to the boat. The boat drivemechanism s
11、hould 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, capable of measuringlight emitted from the reaction betwe
12、en 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 instruments used to determine the precision of this test meth
13、od.5.3 Combustion Tube, fabricated from quartz. The inlet 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
14、 high-temperature oxidation zone. The oxidation section should belarge enough to ensure complete oxidation of the sample.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.
15、Current edition approved June 1, 2011. Published July 2011. Originally approvedin 1995. Last previous edition approved in 2010 as D576210. DOI: 10.1520/D5762-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book o
16、f ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*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 19428-2959, United States.Combustion tubes re
17、commended for the two furnaces in 5.5.1and 5.5.2 are described in 5.3.1 and 5.3.2. Other configurationsare acceptable if precision and bias are not degraded.5.3.1 Quartz combustion tube for use with the single-zonefurnace is illustrated in Fig. 1. A water-jacket around the inletsection can be used t
18、o cool the boat prior to sample injection.5.3.2 Quartz combustion tube for use with the two-zonefurnace is illustrated in Fig. 2. Fig. 3 illustrates a combustiontube for a two-zone furnace that is equipped with the ability toswitch to a pure oxygen carrier gas flow after the boat has beenfully exten
19、ded into the furnace (consult the instrument manualto determine if the instrument changes to a pure oxygen carriergas flow after the boat is inserted). The outlet end of thepyrolysis tube is constructed to hold a removable quartz inserttube. The removable quartz insert tube is packed with anoxidatio
20、n catalyst as recommended by the instrument manu-facturer.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 membranedrying
21、 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 needle valve
22、s,flow restrictors or mass flow controllers. Furnaces that areoperated at temperatures below 1050C 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 maintaining a st
23、able furnace temperature of 1100 625C.5.5.2 Two-zone tube furnace with temperature controllerscapable of maintaining the temperature of each furnace zoneindependently from 950 to 1050C (see 5.5). Or two-zone tubefurnace equipped with the ability to change to a pure oxygencarrier gas flow after the b
24、oat is fully extended in to the furnaceand temperature controllers capable of maintaining the tem-perature of each furnace zone independently to 950C.5.6 Microlitre Syringe, of 5 or 10-L capacity, capable ofaccurately delivering microlitre quantities.5.7 Ozone Generator, to supply ozone to the detec
25、torreaction 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 the Commit-te
26、e 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,C13H9N, molecul
27、ar weight 179.21, 7.82 mass% 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 % minimumpurity,
28、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:6.6.1 Volumetric PreparationAccurately weigh (to thenearest 0.1
29、 mg) approximately 0.64 g of acridine into a tared100-mL volumetric flask.Add xylene to dissolve, then dilute tovolume with xylene. Calculate the nitrogen content of the stocksolution to the nearest milligram of nitrogen per litre. Thisstock can be further diluted to desired nitrogen concentrations.
30、3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacope
31、iaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Quartz Combustion Tube (Single-Zone Furnace)D5762 112(WarningRemake standard solutions on a regular basisdepending upon frequency of use and age. Typically, standardshave a useful life of approximately three mo
32、nths.)6.6.2 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 thenitrogen content of the stock solution to the nearest milligramof nitr
33、ogen per kilogram. Convert the concentration to milli-grams of nitrogen per litre by multiplying by the density ofxylene. This stock can be further diluted to desired nitrogenconcentrations. (WarningRemake standard solutions on aregular basis depending upon frequency of use and age.Typically, standa
34、rds have a useful life of approximately threemonths.)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 absorbentmat
35、erial 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 remainig drops of the sample fromthe ti
36、p 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)portions of o
37、ne or moreliquid petroleum or product standards of known nitrogencontent and not used in the generation of the calibration curve.FIG. 2 Quartz Combustion Tube (Two-Zone Furnace)FIG. 3 Quartz Combustion Tube (for two zone furnace equipped with the ability to switch to pure oxygen carrier gas flow)D57
38、62 113A 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)preferably portionsof one or more liquid petroleum materials that are stable andrepresentative of the samples of interest. These QC s
39、amplescan be used to verify that the testing process is in statisticalcontrol 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 tempera
40、tures and rupture the container. For suchsamples, do not fill the container to 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 sam
41、ples should be analyzed as soon aspossible after taking from bulk supplies to 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 s
42、amples require heating in order to thoroughlyhomogenize.8. Preparation of Apparatus8.1 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 th
43、e pyrolysis temperature to therecommended operating conditions using the following 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 th
44、e ability tochange to a pure oxygen carrier gas flow after the boat has beenfully extended into the furnace, adjust the combustion tube gasflows to the following values: pyrolysis oxygen, 360 6 36mL/min; inlet oxygen, 60 6 6 mL/min; and inert carrier inlet,155 6 15 mL/min. Other gas flows may be use
45、d if it can beshown that precision and bias are not degraded. Set the furnacetemperature to 1100 6 25C. Adjust the boat drive mechanismto obtain a drive rate of 150 6 10 mm/min. Refer to themanufacturers instructions for descriptions of these settings.8.2.2 For the two-zone furnace without the abili
46、ty to changeto a pure oxygen carrier gas flow after the boat has been fullyextended into the furnace, adjust the combustion tube gas flowsto the following values: combustion oxygen, 165 616 mL/min;inlet inert carrier, 85 6 9 mL/min; and boat inert carrier, 50 65 mL/min. Other gas flows may be used i
47、f it can be shown thatprecision and bias are not degraded. Set the inlet furnacetemperature to 1050 6 25C, and the outlet furnace tempera-ture to 925 6 25C. Adjust the boat drive mechanism to obtaina drive rate of 150 6 10 mm/min (boat speed number 4). Referto the manufacturers instructions for the
48、description of thesesettings. (WarningHigh 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, adju
49、st the combustion tube gasflows to the following values: main oxygen, 400 6 40 mL/min;inlet argon carrier, 0.4 6 0.04 L/min, and inlet oxygen carrier,0.4 6 0.04 L/min. Other gas flows may be used if it can beshown that precision and bias are not degraded. Set the inletfurnace temperature to 600 6 25C, and the outlet (catalyst)temperature to 950 6 25C. Set the automatic boat control asfollows: 1 Fuc FWD 125 speed 10 time 30, 2 Fuc 285 speed 05time 30, 5 Fuc time 30, 6 Fuc time 90, A Fuc time 60. Refer tomanufacturers instructions for a description
