UOP 547-2013 LABORATORY HYDROGEN SULFIDE AND MERCAPTAN EXTRACTION.pdf

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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 1963, 1997, 2013 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、Laboratory Hydrogen Sulfide and Mercaptan Extraction UOP Method 547-13 Scope The purpose of this method is to remove hydrogen sulfide, and to reduce the mercaptan content, in hydrocarbons that are liquid at room temperature by extraction with sodium hydroxide under standardized conditions. The treat

5、ed distillate may be processed further in a pilot plant or tested for properties other than hydrogen sulfide and mercaptan content. Such additional processing or testing is beyond the scope of this method. The results obtained by this method can also be correlated empirically with results from a com

6、mercial extractor as a check for extractor performance. When the characteristics of a given extractor are known in terms of this test, this procedure can be used to estimate results to be expected when extracting a new stock. This type of correlation is also beyond the scope of this method. Referenc

7、es ASTM Method D5191, “Vapor Pressure of Petroleum Products (Mini Method),” www.astm.org UOP Method 41, “Doctor Test for Petroleum Distillates,” www.astm.org UOP Method 163, “Hydrogen Sulfide and Mercaptan Sulfur in Liquid Hydrocarbons,” www.astm.org Outline of Method The hydrocarbon sample is extra

8、cted under a nitrogen atmosphere with a sodium hydroxide solution in a batchwise operation. The extraction can be performed at room temperature, or at higher temperatures, to simulate commercial extractor conditions. Additional extractions of the same sample are made after draining the used sodium h

9、ydroxide and repeating with a fresh batch of sodium hydroxide. The raw and treated samples at all extraction stages are tested for hydrogen sulfide and mercaptan content. Finally, the extracted sample is water-washed to remove any residual caustic. Apparatus References to suppliers and catalog numbe

10、rs are included as a convenience to the method user. Other suppliers may be used, unless stated otherwise. Adapter, gas inlet, Reliance Glass, Cat. No. R-1101-100 2 of 7 547-13 Bath, water, Fisher Scientific, Cat. No. 15-462-2Q Centrifuge, general purpose, Fisher Scientific, Cat. No. 75-004-241with

11、rotor, Cat. No. 75-003-607, and adapter, Cat. No. 75-003-792 Chromatographic column, glass, with removable Teflon stopcock and replaceable glass tip, 300-mm long, 22-mm ID, VWR Scientific, Cat. No. 21503-123 Condenser, reflux Dewar, Reliance Glass, Cat. No. R-2909-100 Cylinders, graduated, Class B,

12、250-, 500-, and 2000-mL, Fisher Scientific, Cat. Nos. 08-550F, -550G, and -550J, respectively Flask, round bottom, 2000-mL, stopcock on bottom, Teflon stopcock plug, Reliance Glass, Cat. No. R-3990T-206 Heating mantle, bottom opening for 2000-mL flask, Reliance Glass, Cat. No. R-9020-104 Marker, loc

13、al supply Pipet, Class B, 100-mL, Fisher Scientific, Cat. No. 13-650U Pipet filler, Fisher Scientific, Cat. No. 31-681-102A Regulator, nitrogen, two-stage high purity, 0-200 kPa (0-30 psi), Matheson Tri-Gas, Model 3121-580. Set the output pressure at not more than 35 kPa (5 psig) to avoid overpressu

14、ring the glassware. Stirrer blade, Teflon, Reliance Glass, Cat. No. R-6040T-100 Stirrer, Fisher Scientific, Cat. No. 14-500-214 Stirrer, shaft adapter, universal joint, Reliance Glass, Cat. No. R-6118-010 Teflon sleeve, to fit the 2000-mL round bottom flask ground joints, Reliance Glass, Cat. No. R-

15、8100-118, 3 required Temperature controller, Fisher Scientific, Cat. No. 13-931-12 Thermometer, -20 to 110C, Fisher Scientific, Cat. No. 15-160-20 Timer, benchtop, Fisher Scientific, Cat. No. 06-662-51 Reagents and Materials References to suppliers and catalog numbers are included as a convenience t

16、o the method user. Other suppliers may be used, unless stated otherwise. References to water mean deionized or distilled water. Bottle, glass, 125-mL, Fisher Scientific, Cat. No. 02-911-784 Bottle, glass, 1.9-L, Fisher Scientific, Cat. No. 02-991-895 Bottle, polypropylene, 2-L, Fisher Scientific, Ca

17、t. No. 02-924A Centrifuge tubes, 250-mL, ploypropylene, Fisher Scientific, Cat. No. 05-538-53 Cotton, absorbent, Fisher Scientific, Cat. No. 07-886 Dry ice, crushed, local supply Ice, water, local supply 3 of 7 547-13 Isopar M, Fisher Scientific, Cat. No. NC9872259 Nitrogen, zero gas, 99.99% minimum

18、 purity, total hydrocarbons less than 0.5 ppm as methane Sodium hydroxide, 50% mass/mass, Fisher Scientific, Cat. No. SS410-4 Sodium hydroxide, 15% mass/mass. Add, slowly, 300 g of the 50% sodium hydroxide to a 2-L polypropylene bottle containing 700 g of water while cooling on wet ice. Invert sever

19、al times to mix thoroughly. Stoppers, to fit sample transfer apparatus, Figure 2, and sample containers Tubing, Teflon, Nalgene, 25 feet, 6.4-mm OD, Fisher Scientific, Cat. No. 14-176-179 Water, deionized or distilled Procedure The analyst is expected to be familiar with general laboratory practices

20、 and the equipment being used. Dispose of all reagents, materials, and samples in an environmentally safe manner according to local regulations. In both Procedures A and B, a minimum of four extractions is recommended. However, more extractions may be done at the direction of the customer. All of th

21、e following operations (Procedures A and B) must be performed in a properly operating fume hood. A. Extraction at Room Temperature 1. Set up the apparatus as shown in Figure 1. Use Teflon sleeves to seal the ground glass joints. Mark the flask at 1.6 L, liquid volume. 2. Fill approximately two third

22、s of the condenser with dry ice. Slowly add approximately 50 mL of Isopar M to the condenser. Do not exceed the condenser capacity. 3. Purge the empty flask with a flow of nitrogen for 2 to 5 minutes. This will remove air from the flask. Ensure that the outlet pressure of the nitrogen regulator does

23、 not exceed 35 kPa (5 psig) to prevent overpressuring any glassware in the event of a blockage. 4. Reduce the nitrogen to a gentle flow for the following operations. 5. Transfer approximately 1.6 L of the sample into the flask through the condenser joint (remove condenser first). Ensure an air-free

24、transfer of the sample, see Figure 2. If light hydrocarbons are present, the sample should be chilled prior to the transfer step. Once transferred, the sample should be allowed to reach room temperature before extraction with the sodium hydroxide. 6. Add, by graduated cylinder, 160 mL of 15% sodium

25、hydroxide solution to the flask containing the sample through the nitrogen inlet. Do not stop the nitrogen purge, simply loosen the connection and add the sodium hydroxide solution slowly. 7. Turn the stirrer on and stir at full speed for ten minutes. The stirrer should achieve a strong vortex witho

26、ut excessive splashing. 8. Allow the mixture to settle until there is a distinct phase separation. 9. Open the stopcock at the bottom of the flask. Drain and discard the caustic layer. 4 of 7 547-13 10. Remove, by pipet, 100 mL of the hydrocarbon layer for the doctor test (UOP Method 41, “Doctor Tes

27、t for Petroleum Distillates”) and mercaptan sulfur determination (UOP Method 163, “Hydrogen Sulfide and Mercaptan Sulfur in Liquid Hydrocarbons”). Transfer to a nitrogen purged sample bottle. If the 100-mL hydrocarbon sample is turbid, it may be necessary to centrifuge the sample to remove entrained

28、 caustic prior to performing UOP Method 163. 11. Repeat the extraction three more times (or as many times as requested) with a fresh batch of caustic followed by separation and analysis as described in Steps 6 through 10. Maintain a constant ratio of sodium hydroxide to sample during all extractions

29、. For example, since 100 mL of the hydrocarbon sample were removed after the first extraction, the amount of sodium hydroxide to be used for the second extraction should be 150 mL. 12. After the final caustic extraction, wash the hydrocarbon layer by adding 400 mL of water to the flask containing th

30、e hydrocarbon sample. 13. Turn the stirrer on and stir for five minutes. The stirrer should achieve a strong vortex without excessive splashing. 14. Allow the mixture to settle until there is a distinct phase separation. 15. Open the stopcock at the bottom of the flask. Drain and discard the aqueous

31、 layer. 16. Purge the chromatographic column packed with 90 mm of the absorbent cotton with nitrogen. Filter the hydrocarbon layer using the chromatographic column packed with 90 mm of the absorbent cotton. Collect the sample in a nitrogen purged glass bottle. If the sample contains light hydrocarbo

32、ns, the nitrogen purged glass bottle should be placed in a wet ice bath to collect the filtered sample. To ensure that there has been adequate protection against air oxidation of mercaptans, determine the total sulfur on the raw distillate sample and on the sample after the final stage of washing. I

33、f the total sulfur depletion does not correspond with the disappearance of the hydrogen sulfide and mercaptan sulfur, repeat the extraction, ensuring that air is excluded. The sample is now ready for inspection tests or further processing. B. Extraction Above Room Temperature When this method is use

34、d to compare results with a commercial extractor, the temperature of the contents of the flask should be adjusted to approximately the same temperature that prevails in the commercial extractor. This procedure was found satisfactory, when extracting at 37C, a light straight-run gasoline having an in

35、itial boiling point of 41C and a Reid vapor pressure of 68 kPa. This procedure is not used for extracting pentane or lighter fractions. The customer designates the number of extractions to be performed and the temperature. 1. Set up the apparatus as described in Procedure A, Steps 1 through 4, and p

36、lace a heating mantle under the flask shown in Figure 1. 2. Add the hydrocarbon sample as described in Procedure A, Step 5, and heat to the requested temperature while stirring slowly. Check the temperature periodically until it levels off at the desired temperature. The sample should be chilled pri

37、or to Step 2 if light hydrocarbons are present. A thermometer can be used to check temperature by loosening the gas inlet and inserting the thermometer. 3. Measure 160 mL of the sodium hydroxide solution into a 250 mL graduated cylinder. Immerse the graduated cylinder containing the sodium hydroxide

38、 in a hot water bath and allow it to warm to a few degrees above the extraction temperature. 5 of 7 547-13 This allows for heat loss when measuring the caustic solution. 4. Add the warm sodium hydroxide solution to the flask containing the sample through the nitrogen inlet and repeat Procedure A, St

39、eps 7 through 16. Do not stop the nitrogen purge, simply loosen the connection and add the sodium hydroxide solution slowly. Precision Based on a limited number of replicate extractions made on several sour gasolines, which did not require chilling or special handling, the mercaptan sulfur values on

40、 duplicate sample extractions, at each stage of sodium hydroxide washing should not differ by more than the following: Table Mercaptan Sulfur by UOP Method 163, mass-ppm Range Allowable Difference 1-10 1.0 10-50 1.5 50-100 3.0 100-1000 3 to 15 Based on the mean range for 18 pairs, representing seven

41、 stages of extraction, the estimated standard deviation was calculated to be 0.29 mass-ppm (average over the range). Time for Analysis The elapsed time for the extraction will vary according to the ease of separating the aqueous-hydrocarbon emulsion. The labor requirement for a three stage extractio

42、n is four hours. Suggested Suppliers Fisher Scientific, 711 Forbes Ave., Pittsburgh, PA 15219-4785, USA, 1-412-490-8300, Matheson Tri-Gas, 166 Keystone Dr., Montgomeryville, PA 18936, USA, 1-215-641-2700, Reliance Glass Division, Wilmad/Lab Glass, 1455 Elmhurst Rd., Elk Grove Village, IL 60007, USA, 1-847-228-2851, www.lab- VWR International, 1310 Goshen Parkway, West Chester, PA 19380, USA, 1-610-431-1700, 6 of 7 547-13 Figure 1 Stirred Contactor 7 of 7 547-13 Figure 2 Air-Free Sample Transfer Apparatus