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
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3、d. Nonconfidential 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 610.83
4、2.9585 PHONE. C5and Lower Boiling Dienes, Olefins, and Paraffins in Naphthas by GC UOP Method 980-07 Scope This method is for determining C5and lighter diolefins, mono-olefins, and paraffins in olefinic naphthas. Resolved acetylenes and resolved C6hydrocarbons, including resolved dienes, are also id
5、entified. The method is applicable to selective hydrogenation process feeds, products, and other process streams with similar matrices having a final boiling point of 260C or lower. Components that do not elute from the chromatographic system under the specified conditions, if present in the sample,
6、 are not determined. 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 Scanlon, J. T. and Willis, D. E., J
7、ournal of Chromatographic Science, 23, 333-340 (1985) UOP Method 725, “Pentenes and Lower Boiling Hydrocarbons in Olefinic Gasolines by GC,” www.astm.org UOP Method 999, “Precision Statements in UOP Methods,” www.astm.org Outline of Method The sample to be analyzed is injected into a gas chromatogra
8、ph 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 corrected for difference
9、s 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, readability 0.1-mg 2 of 15 980-07 Chromatographic column, 100 m of 0.25-mm ID fused silica capillary, internally co
10、ated to a film thickness of 0.5 micron (bonded) with poly-dimethyl siloxane, Petrocol DH, Supelco, Cat. No. 24160-U Gas chromatograph, temperature programmable with cryogenic cooling, built for capillary column chromatography, utilizing a split injection system, equipped with a glass injection port
11、insert, and a flame ionization detector that will give a minimum peak height response of five times the background noise for 0.01 mass-% n-heptane when operated at the recommended conditions, Agilent Technologies, Model 6890. The inclusion of an autosampler (or autoinjector) is recommended but not r
12、equired. Gas purifier, used to remove oxygen from the hydrogen carrier gas, Mat/Sen, Cat. No. P-200-1 Integrator, or data system, electronic, for obtaining peak areas. This device must integrate areas at a sufficiently fast rate so that narrow peaks, typically obtained from a capillary column, can b
13、e accurately measured. The integrator must have programmable parameters for controlling baseline events, and have graphics capabilities. ChemStation, Agilent Technologies. Leak detector, gas, Alltech Associates, Cat. No. 21-250 Refrigerator, flammable-materials storage, Fisher Scientific, Cat. No. 9
14、7-938-1 Regulator, air, two-stage, high purity, Matheson Gas Products, Model 3122-590 Regulator, hydrogen, two-stage, high purity, Matheson Gas Products, Model 3122-350 Regulator, nitrogen or helium, two-stage, high purity, Matheson Gas Products, Model 3122-580 Sample injector, syringe or injector c
15、apable of introducing a 0.5-L volume of sample. An autosampler (or autoinjector) is recommended, Agilent Technologies, Model 7683. 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, total hy
16、drocarbons 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. 27,070-9 Caps, for autosampler vials, open hole with septum, screw, 9 mm, with Tef/Sil/Tef liner, Fisher Scientific, Ca
17、t. No. 03-377-2A Carbon Dioxide, commercial liquid, 99.5% minimum purity, with full-length eductor tube for liquid withdrawal, for cryogenic cooling n-Heptane, 99.9+% purity, Aldrich, Cat. No. 27,051-2 Hydrogen, zero gas, 99.95% minimum purity, total hydrocarbons less than 0.5 ppm as methane Pipet b
18、ulbs, Fisher Scientific, Cat. No. 13-678-9B 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, Agilent Technologies, Cat. No. 5181-1273 Toluene, 99.8% purity, Aldrich, Ca
19、t. No. 27,037-7 3 of 15 980-07 p-Xylene, 99+% purity, Aldrich, Cat. No. 31,719-5 Vials, 15-mL, with screw cap, Fisher Scientific, Cat. No. 03-339-21J Procedure Chromatographic Technique The analyst is expected to be familiar with the technique of gas chromatography and the equipment being used. 1. I
20、nstall 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, according to the column and gas
21、chromatograph manufacturers instructions. CAUTION: Hydrogen leakage into the confined volume of the column oven can cause a violent explosion. Therefore, it is mandatory to check for leaks each time a connection is made and periodically thereafter. Table 1 Recommended Operating Conditions Carrier ga
22、s hydrogen Mode constant pressure Head pressure 207 kPa gauge (30 psig) Linear velocity 15C 38 cm/sec Equivalent flow 15C 2.6 mL/min Split flow 200 mL/min Injection port temperature 215C Column temperature program Initial temperature 15C Initial hold time 15 min Programming rate A 8C/min Intermediat
23、e temperature 75C Intermediate hold time 14 min Programming rate B 20C/min Final hold temperature 250C Final hold time 27.5 min Detector flame ionization Detector temperature 250C Hydrogen flow rate* 30 mL/min Air flow rate* 400 mL/min Makeup gas nitrogen or helium Makeup gas flow rate* 30 mL/min Sa
24、mple size 0.5 l *Consult the manufacturers instrument manual for suggested flow rates. 4 of 15 980-07 3. Establish the recommended operating conditions as given in Table 1. Different conditions may be used provided they produce the required sensitivity and chromatographic separations equivalent to t
25、hose shown in the Typical Chromatograms (Figures 1, 2, and 3). 4. Program the column oven to 250C. Maintain this temperature until a stable baseline has been obtained at the required sensitivity. 5. Cool the column oven to a stabilized 15C. 6. If using an autosampler, multiple samples may be transfe
26、rred into autosampler vials and preloaded into the tray. 7. 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 autosampler is used. If samples are not to be run immediately, t
27、hey should be refrigerated until they are analyzed. Samples should be removed from refrigerator and well mixed prior to injection. 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 t
28、o the identifications in the Chromatograms, Figures 1, 2, and 3. If necessary, confirm the sites of the aromatic compounds 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
29、. Table 2 Retention Times of Identified Components Typical Retention Time, Min Peak No. Component Identification 5.19 5.23 5.75 5.79 6.33 6.68 6.73 6.83 6.91 7.02 7.11 7.31 7.85 8.19 8.80 8.93 9.42 9.73 9.96 10.19 10.37 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Ethylene Ethane Propylene Propan
30、e 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-butadiene trans-2-Pentene 5 of 15 980-07 Typical Rete
31、ntion Time, Min Peak No. Component Identification 10.72 10.81 11.09 11.26 11.90 12.07 12.14 12.86 13.41 13.88 13.97 14.38 14.66 14.84 15.05 15.17 15.37 15.42 15.96 16.48 16.98 17.08 17.62 17.97 18.03 18.25 18.31 18.44 18.63 18.83 19.15 19.33 19.62 19.72 19.89 19.94 20.38 21.50 21.59 28.88 37.29 37.9
32、3 38.00 39.27 20 21 22 23 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 3,3-Dimethyl-1-butene cis-2-Pentene 2-Methyl-2-butene 1-trans-3-Pentadiene 3-Methyl-1,2-butadiene & Cyclopentadiene 1-cis-3-Pentadiene 2,2-Dimethylbutane 3-M
33、ethyl-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-pentene 1-Hexene 1,4-Hexadiene 2-Ethyl-1-butene
34、n-Hexane cis-3-Hexene trans-3-Hexene trans-2-Hexene 2-Methyl-2-pentene 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-butene Methylcyclopentene Benzene Toluene Ethylbenzene m-Xylene p-Xyl
35、ene o-Xylene 6 of 15 980-07 Calibration This analysis uses internal normalization of the total sample to be quantitative, and requires that all components in the sample which elute from the column under the specified conditions are measured. Any components which do not elute from the column under th
36、e specified conditions are not measured. In order to accurately measure the total sample, certain components beyond the C5range must be identified and calibrated. This is necessary because C6through C8aromatic components that may be present in the sample do not have the same detector response as the
37、 non-aromatic components. All non-aromatic components have essentially the same detector response. 1. Prepare a blend as described in ASTM Method D4307 to contain approximately equal quantities of n-heptane, benzene, toluene, and p-xylene. 2. Analyze the blend in triplicate as described under Chroma
38、tographic Technique. The peak areas from each of the three runs should not deviate from the average by more than 3%. If greater deviations occur, make certain that there are no problems with the equipment or technique, and then make additional runs until the required repeatability is obtained on thr
39、ee consecutive runs. A calibration blend is run when the method is initially set up and thereafter when changes have been made to the equipment or periodically to verify proper calibration. 3. Based upon 3 replicate runs of the blend, determine the average relative response factors to four decimal p
40、laces for each component using Equation 1 and n-heptane as reference: CDABF = ( )1 where: A = component of interest, mass-% B = area of n-heptane peak C = n-heptane, mass-% D = area of component of interest F = relative response factor Calculated relative response factors should be similar to the th
41、eoretical relative response factors shown in Table 3. The theoretical relative response factors were calculated using the effective carbon number (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 t
42、he apparatus, operating conditions, and blend preparation procedures. Table 3 Theoretical Relative Response Factors n-Heptane 1.000 Benzene 0.909 Toluene 0.919 p-Xylene 0.927 All C8aromatics will use the same factor as p-xylene. Due to the volatility of C6and lighter material, and the similarity of
43、response factors, the response factor for n-heptane can represent all paraffins, olefins, diolefins, and unknowns. 7 of 15 980-07 Calculations Obtain peak areas for each individual component or group of components and calculate the concentration of each identified peak in the sample to the nearest 0
44、.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 components T = the sum of the products, PF, of all the recorded peaks Note The same equipment and conditions used in this method (UOP 980) may
45、 be used for UOP Method 725 (which identifies paraffins and olefins through C5only). Precision Precision statements were determined using UOP Method 999 from precision data obtained using an autosampler. Repeatability and Intermediate Precision A nested design was carried out for determining compone
46、nts in one olefinic hydrocarbon sample with four analysts in one laboratory. Each analyst carried out tests on two separate days, performing two tests each day. The total number of tests for each component was 16. The precision data are summarized in Table 4. Two tests performed by the same analyst
47、on the same day should not differ by more than the repeatable allowable difference with 95% confidence. Two tests performed in one laboratory by different analysts on different days should not differ by more than the intermediate precision allowable difference with 95% confidence. The data in Table
48、4 are a short-term estimate of repeatability. When the test is run routinely, a control standard and chart should be used to develop a better estimate of the long-term repeatability. Reproducibility There is insufficient data to calculate reproducibility of the test at this time. Time for Analysis T
49、he elapsed time for one analysis is 1.5 hours. The labor requirement is 0.5 hour. Suggested Suppliers Agilent Technologies, 2850 Centerville Rd., Wilmington, DE 19808-1610 (302-633-8000) Aldrich Chemical Co., P.O. Box 355, Milwaukee, WI 53201 (414-273-3850) www.sigma- Alltech Associates Inc., 2051 Waukegan Rd., Deerfield, IL 60015 (847-948-8600) 8 of 15 980-07 Matheson Gas Products Inc., 166 Keystone Drive, Montgomeryville, PA 18936 (215-641-2700) Mat/Sen, 26272 Twelve Trees
