ASTM D5762-2008 516 Standard Test Method for Nitrogen in Petroleum and Petroleum Products by Boat-Inlet Chemiluminescence.pdf

1、Designation: D 5762 08An American National StandardStandard Test Method forNitrogen in Petroleum and Petroleum Products by Boat-InletChemiluminescence1This standard is issued under the fixed designation D 5762; the number immediately following the designation indicates the year oforiginal adoption o

2、r, in the 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,

3、including petroleum process streams andlubricating oils in the concentration range from 40 to 10 000g/g nitrogen. For light hydrocarbons containing less than 100g/g nitrogen, Test Method D 4629 can be more appropriate.1.2 The values stated in SI units are to be regarded asstandard. No other units of

4、 measurement 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 and health practices and determine the applica-bility of regulator

5、y limitations prior to use. Specific warningstatements are given in Section 6, 7.1, 8.2, and 8.2.2.2. Referenced Documents2.1 ASTM Standards:2D 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD 4629 Test Met

6、hod for Trace Nitrogen in Liquid Petro-leum Hydrocarbons by Syringe/Inlet Oxidative Combus-tion and Chemiluminescence DetectionD 6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System Performance3. Summary of Test Method3.1 A

7、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). The light em

8、itted 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 hydrogenate,

9、 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 controland in

10、 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 equivalent (see 6.8

11、) 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, capable of measur

12、inglight 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 instruments used to d

13、etermine the precision of this test method.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.Current edition approved July 1, 2008. Published August 2008. Originallyapprov

14、ed in 1995. Last previous edition approved in 2005 as D 576205.2For 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 standards Document Summary page onthe ASTM websit

15、e.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.5.3 Combustion Tube, fabricated from quartz. The inlet endof the tube shall be large enough to accept the sample boat

16、 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 should belarge enough to ensure complete oxidation of the sample

17、.Combustion tubes recommended 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 inlets

18、ection can be used to 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

19、 has beenfully extended 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 pa

20、cked with anoxidation 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, scrubb

21、er, a membranedrying 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,

22、such as needle valves,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

23、 of maintaining a stable 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

24、gas flow after the boat 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 suppl

25、y ozone 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 specificati

26、ons of 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 Acri

27、dine,C13H9N, molecular 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), 99.9

28、98 % 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.)3Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, W

29、ashington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1

30、 Quartz Combustion Tube (Single-Zone Furnace)D57620826.6 Nitrogen Stock Solution, 500 ng nitrogen/LAccurately weigh (to the nearest 0.1 mg) approximately 0.64 gof acridine into a tared 100-mL volumetric flask.Add xylene todissolve, then dilute to volume with xylene. Calculate thenitrogen content of

31、the stock solution to the nearest milligramof nitrogen per litre. This stock can be further diluted to desirednitrogen concentrations. (WarningRemake standard solu-tions on a regular basis depending upon frequency of use andage. Typically, standards have a useful life of approximatelythree months.)6

32、.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 absorbentmaterial that is stable and capable of withstanding tempe

33、raturesinside 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 tip of the syringe needle prior to introduction of the s

34、ample 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 one or moreliquid petroleum or product standards of kno

35、wn 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)preferably portionsof one or more liquid petroleum materials tha

36、t are stable andrepresentative of the samples of interest. These QC samplescan be used to verify that the testing process is in statisticalcontrol as described in Section 10.FIG. 2 Quartz Combustion Tube (Two-Zone Furnace)FIG. 3 Quartz Combustion Tube (for two zone furnace equipped with the ability

37、to switch to pure oxygen carrier gas flow)D57620837. Sampling7.1 Obtain a test sample in accordance with Practice D 4057or D 4177.(WarningSamples that are collected at tempera-tures below room temperature can undergo expansion atlaboratory temperatures and rupture the container. For suchsamples, do

38、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 samples should be analyzed as soon aspossible after taki

39、ng 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 samples require heating in order to thoroughlyhomogeni

40、ze.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 the pyrolysis temperature to therecommended operating c

41、onditions 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 the ability tochange to a pure oxygen carrier gas flow

42、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 used if it can beshown that precision and bias are not d

43、egraded. 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 ability to changeto a pure oxygen carrier gas flow after t

44、he 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 if it can be shown thatprecision and bias are not degr

45、aded. 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 description of thesesettings. (WarningHigh temperatur

46、e 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 to the following valu

47、es: 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.

48、 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 of these settings.8.3 Insert boat into furnace for a minimum of 2 min toremove any residual nitrogen

49、 species.9. Calibration and Standardization9.1 Prepare calibration standards containing 1, 5, 10, 50,and 100 ng nitrogen/L in xylene by volumetric dilution of the500-ng nitrogen/L nitrogen stock solution.9.2 Five microlitres of the material to be analyzed (see Note3) shall be quantitatively placed in the sample boat formeasurement of chemiluminescence response. There are twoalternative injection procedures available, the volumetric andthe gravimetric procedures.NOTE 3The formation of NO and NO2from oxidative combustion ofnitrogen containing hydroc