UOP 980-2017 C5 and Lower Boiling Dienes Olefins and Paraffins in Naphthas by GC.pdf

1、 IT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TO DETERMINE THE APPLICABILITY OF REGULATORY LIMITATIONS PRIOR TO USE. EFFECTIVE HEALTH AND SAFETY PRACTICES ARE TO BE FOLLOWED WHEN UTILIZING THIS PROCEDURE. FAILURE TO UTILIZE THIS PROCEDURE IN THE MANNER PRESCRIB

2、ED HEREIN CAN BE HAZARDOUS. SAFETY DATA SHEETS (SDS) OR EXPERIMENTAL SAFETY DATA SHEETS (ESDS) FOR ALL OF THE MATERIALS USED IN THIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTION EQUIPMENT (PPE). COPYRIGHT 2003, 2007, 2017 UOP LLC. All rights reserved. Nonconfiden

3、tial UOP Methods are available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, USA. The UOP Methods may be obtained through the ASTM website, www.astm.org, or by contacting Customer Service at serviceastm.org, 610.832.9555 FAX, or 610.832.9585 PHONE.

4、C5 and Lower Boiling Dienes, Olefins, and Paraffins in Naphthas by GC UOP Method 980-17 Scope This method is for determining C5 and lighter diolefins, mono-olefins, and paraffins in olefinic naphthas. Resolved acetylenes and resolved C6 hydrocarbons, including resolved dienes, are also identified. T

5、he method is applicable to selective hydrogenation process feeds, products, and other process streams with similar matrices having a final boiling point of 260 C or lower. Components that do not elute from the chromatographic system under the specified conditions, if present in the sample, are not d

6、etermined. The lower limit of detection for any compound is 0.01 mass-%. The Appendix describes an extension of the method to analyze LPG samples. References ASTM Method D 4307, “Preparation of Liquid Blends for Use as Analytical Standards,” www.astm.org ASTM Method D 5854, “Standard Practice for Mi

7、xing and Handling of Liquid Samples of Petroleum and Petroleum Products,” www.astm.org Scanlon, J. T. and Willis, D. E., Journal of Chromatographic Science, 23, 333-340 (1985) UOP Method 999, “Precision Statements in UOP Methods,” www.astm.org Outline of Method The sample to be analyzed is injected

8、into a gas chromatograph that is equipped with a fused silica capillary column, internally coated with (bonded) poly-dimethyl siloxane, and a flame ionization detector (FID). The mass-% composition of the sample is obtained by the internal normalization technique, wherein the peak areas are first co

9、rrected for differences in response and then normalized to 100%. Apparatus References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used. Balance, readable to 0.1 mg Chromatographic column, 100 m of 0.25-mm ID fused silica capillary, intern

10、ally coated to a film thickness of 0.5 micron (bonded) with poly-dimethyl siloxane, Petrocol DH, Sigma-Aldrich, Cat. No. 24160-U 2 of 15 980-17 Data system, electronic, for obtaining peak areas. This device must integrate areas at a sufficiently fast rate so that narrow peaks, typically obtained fro

11、m a capillary column, can be accurately measured. The integrator must have programmable parameters for controlling baseline events, and have graphics capabilities. ChemStation, Agilent Technologies. Electronic leak detector, Agilent gas leak detector, Agilent, Cat. No. G3388B Freezer, flammable-mate

12、rials storage, Fisher Scientific, Cat. No. 05-FFE-ETSA Gas chromatograph, temperature programmable with cryogenic cooling, built for capillary column chromatography, utilizing a split injection system, equipped with a glass injection port insert, and a flame ionization detector that will give a mini

13、mum peak height response of five times the background noise for 0.01 mass-% n-heptane when operated at the recommended conditions, Agilent Technologies, Model 7890. The inclusion of an autosampler (or auto injector) is recommended but not required. Gas purifier, hydrogen carrier gas purifier, VICI M

14、etronics, Cat. No. P200-1 Regulator, air, two-stage, high purity, Matheson Tri-Gas, Model 3120A-590 Regulator, hydrogen, two-stage, high purity, Matheson Tri-Gas, Model 3120A-350 Regulator, nitrogen or helium, two-stage, high purity, Matheson Tri-Gas, Model 3120A-580 Sample injector, syringe or inje

15、ctor capable of introducing a 0.5 L volume of sample. An autosampler (or auto injector) is recommended, Agilent Technologies, Model 7693A. Reagents and Materials References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used. Air, zero gas,

16、total hydrocarbons less than 2.0 ppm as methane Autosampler vials, glass, 12- x 32- mm, for Agilent autosampler, Fisher Scientific, Cat. No. 03-391-8 Benzene, 99.9% purity, Aldrich, Cat. No. 270709 Caps, for autosampler vials, open hole with septum, screw, 9- mm, with Tef/Sil/Tef liner, Fisher Scien

17、tific, Cat. No. 03-377-2A Carbon Dioxide, commercial liquid, 99.5% minimum purity, with full-length eductor tube for liquid withdrawal, for cryogenic cooling Liquid Nitrogen, commercial liquid, obtained locally. n-Heptane, 99.9+% purity, Sigma-Aldrich, Cat. No. 270512 Hydrogen, zero gas, 99.95% mini

18、mum purity, total hydrocarbons less than 0.5 ppm as methane Pipet bulb, 1 mL, Fisher Scientific, Cat. No. 03-448-25 Pipets, disposable, Pasteur, Fisher Scientific, Cat. No. 13-678-20A Nitrogen or helium, zero gas, total hydrocarbons less than 0.5 ppm as methane Syringe, for sample injector, 5- L, Ag

19、ilent Technologies, Cat. No. 51811273 Toluene, 99.8% purity, Sigma-Aldrich, Cat. No. 270377 Vials, 15- mL, with screw cap, Fisher Scientific, Cat. No. 03-339-21J 3 of 15 980-17 p-Xylene, 99+% purity, Sigma-Aldrich, Cat. No. 317195 Procedure The analyst is expected to be familiar with general laborat

20、ory practices, the technique of gas chromatography, and the equipment being used. Dispose of used supplies and samples in an environmentally safe manner according to applicable regulations. Sampling Obtain the sample by following the procedures described in ASTM Practice D 4307, “Preparation of Liqu

21、id Blends for Use as Analytical Standards,” ASTM Practice D 5854, “Standard Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products,” or other reliable technique. Chromatographic Technique The analyst is expected to be familiar with the technique of gas chromatography

22、and the equipment being used. 1. Install the gas purifier in the supply line between the carrier gas source and the carrier gas inlets on the gas chromatograph. Column life is significantly reduced if the gas purifier is not used. 2. Install the fused silica capillary column in the gas chromatograph

23、, according to the column and gas chromatograph manufacturers instructions. CAUTION: Hydrogen leakage into the confined volume of the column oven can cause a violent explosion. It is mandatory to check for leaks each time a connection is made and periodically thereafter. Table 1 Recommended Operatin

24、g Conditions Carrier gas hydrogen Mode constant flow Head pressure 207 kPa gauge (30 psig) Linear velocity 15 C 38 cm/sec Equivalent flow 15 C 2.6 mL/min Split flow 200 mL/min Injection port temperature 215 C Column temperature program Initial temperature 15 C Initial hold time 15 min Programming ra

25、te A 8 C/min Intermediate temperature 75 C Intermediate hold time 14 min Programming rate B 20 C/min Final hold temperature 250 C Final hold time 27.5 min Detector flame ionization Detector temperature 250 C Hydrogen flow rate* 30 mL/min Air flow rate* 400 mL/min Makeup gas nitrogen or helium Makeup

26、 gas flow rate* 30 mL/min Sample size 0.5 L *Consult the manufacturers instrument manual for suggested flow rates. 4 of 15 980-17 3. Establish the recommended operating conditions as given in Table 1. Different conditions may be used provided they produce the required sensitivity and chromatographic

27、 separations equivalent to those shown in the Typical Chromatograms (Figures 1, 2, and 3). 4. Program the column oven to 250 C. Maintain this temperature until a stable baseline has been obtained at the required sensitivity. 5. Cool the column oven to a stabilized 15 C. 7. In order to retain the lig

28、ht components, all samples should be placed in a freezer for about 30 minutes prior to sampling into vials for injections. Inject 0.5 L of the sample to be analyzed into the gas chromatograph and start the integrator and column temperature programming sequence. Better precision is obtained when an a

29、utosampler is used. If using an autosampler, multiple samples may be transferred into autosampler vials and preloaded into the tray. If samples are not to be run immediately, they should be placed in a freezer until they are analyzed. Samples should be removed from freezer and well mixed prior to in

30、jection. 8. Identify the components by comparing the resultant chromatogram with the Typical Chromatograms (see Figures 1, 2, and 3) and Table 2. The Peak No. in Table 2 refers to the identifications in the Typical Chromatograms, Figures 1, 2, and 3. If necessary, confirm the sites of the aromatic c

31、ompounds by comparison with the calibration blend (see Calibration). Group all unidentified components as Unknowns. Any individual peak or peaks can be identified and reported separately. Table 2 Identified Components Peak No. Component Identification 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

32、20 21 22 23 Ethylene* Ethane* Propylene Propane Isobutane 1-Butene & Isobutylene 1,3-Butadiene n-Butane Vinylacetylene trans-2-Butene Ethylacetylene & 2,2-Dimethylpropane cis-2-Butene 1,2-Butadiene 3-Methyl-1-butene Isopentane 1,4-Pentadiene 1-Pentene 2-Methyl-1-butene n-Pentane 2-Methyl-1,3-butadie

33、ne trans-2-Pentene 3,3-Dimethyl-1-butene cis-2-Pentene 2-Methyl-2-butene 1-trans-3-Pentadiene 5 of 15 980-17 Peak No. Component Identification 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 3-Methyl-1,2-butadiene & Cyclopentadiene

34、 1-cis-3-Pentadiene 2,2-Dimethylbutane 3-Methyl-1,4-pentadiene Cyclopentene 4-Methyl-1-pentene 3-Methyl-1-pentene Cyclopentane 2,3-Dimethylbutane 2,3-Dimethylbutene cis-4-Methyl-2-pentene 2-Methylpentane trans-4-Methyl-2-pentene 2-Methyl-1,4-pentadiene 1,5-Hexadiene 3-Methylpentane 2-Methyl-1-penten

35、e 1-Hexene 1,4-Hexadiene* 2-Ethyl-1-butene n-Hexane cis-3-Hexene trans-3-Hexene trans-2-Hexene 2-Methyl-2-pentene & 3-Methylcyclopentene cis-3-Methyl-2-pentene cis-2-Hexene 2,3-Dimethyl-1,3-butadiene 3-Methyl-trans-2-pentene trans-1,3-Hexadiene cis-1,3-Hexadiene Methylcyclopentane 2,3-Dimethyl-2-but

36、ene Methylenecyclopentane Benzene & 1-Methylcyclopentene Toluene Ethylbenzene m-Xylene p-Xylene o-Xylene *Unnumbered components are not shown in Figures 1, 2, and 3. Calibration This analysis uses internal normalization of the total sample to be quantitative, and requires that all components in the

37、sample which elute from the column under the specified conditions are measured. Any components which do not elute from the column under the specified conditions are not measured. In order to accurately measure the total sample, certain components beyond the C5 range must be identified and calibrated

38、. This is necessary because C6 through C8 aromatic components that may be present in the sample do not have the same detector response as the non-aromatic components. All non-aromatic components have essentially the same detector response. 6 of 15 980-17 1. Prepare a blend as described in ASTM Metho

39、d D4307 to contain approximately equal quantities of n-heptane, benzene, toluene, and p-xylene. 2. Analyze the blend in triplicate as described under Chromatographic Technique. The peak areas from each of the three runs should not deviate from the average by more than 3%. If greater deviations occur

40、, make certain that there are no problems with the equipment or technique, and then make additional runs until the required repeatability is obtained on three consecutive runs. A calibration blend is run when the method is initially set up and thereafter when changes have been made to the equipment

41、or periodically to verify proper calibration. 3. Based upon three replicate runs of the blend, determine the average relative response factors to four decimal places for each component using Equation 1 and n-heptane as reference: CDABF 1 where: A = component of interest, mass-% B = area of n-heptane

42、 peak C = n-heptane, mass-% D = area of component of interest F = relative response factor Calculated relative response factors should be similar to the theoretical relative response factors shown in Table 3. The theoretical relative response factors were calculated using the effective carbon number

43、 (ECN) concept as described by Scanlon and Willis. If the determined relative response factors differ by more than 10% from those shown in Table 3, check the apparatus, operating conditions, and blend preparation procedures. Table 3 Theoretical Relative Response Factors n-Heptane 1.000 Benzene 0.909

44、 Toluene 0.919 p-Xylene 0.927 All C8 aromatics will use the same factor as p-xylene. Due to the volatility of C6 and lighter material, and the similarity of response factors, the response factor for n-heptane can represent all paraffins, olefins, diolefins, and unknowns. Calculations Obtain peak are

45、as for each individual component or group of components and calculate the concentration of each identified peak in the sample to the nearest 0.01 mass-% using Equation 2: Component, mass-% = TPF100 (2) where: F = relative response factor, from Equation 1 P = area of individual component or group of

46、components T = the sum of the products, PF, of all the recorded peaks Precision Precision statements were determined using UOP Method 999 from precision data obtained using an autosampler. 7 of 15 980-17 Repeatability, Site Precision and Reproducibility A nested design was carried out for determinin

47、g components in one olefinic hydrocarbon sample by two analysts on two separate days, performing two analyses each day in three separate laboratories for a total of 24 analyses. Using a stepwise analysis of variance procedure, the within-day estimated standard deviations (esd) were calculated at the

48、 concentration means listed in Table 4. Two analyses performed in one laboratory by the same analyst on the same day should not differ by more than the repeatability allowable differences shown in Table 4 with 95% confidence. Two analyses performed in one laboratory by different analysts on differen

49、t days should not differ by more than the site precision allowable differences shown in Table 4 with 95% confidence. Two tests performed by different analysts in different laboratories on different days should not differ by more than the reproducibility allowable difference shown in Table 4 with 95% confidence. Table 4 Repeatability, Site Precision and Reproducibility, mass-% Repeatability Site Precision Reproducibility Component Mean Within Day esd Allowable Difference Within Lab esd Allowable Difference Between Lab esd Allowable Difference C