1、SAMPLING AND HANDLING OF GASOLINES, DISTILLATE FUELS AND C3-C4FRACTIONS UOP Method 516-00 SCOPE This method is for the preparation and cleaning of sample cylinders, and for sampling techniques necessary to obtain an air-free sample of a liquid hydrocarbon. The procedures are applicable to liquefied
2、natural gases, high vapor pressure gasolines, various liquefied petroleum gases, air-unstable gasolines or other liquid hydrocarbon products that require rigorous exclusion of air. Sampling for the analysis of sulfur or other heteroatom compounds in C3-C4fractions requires a special cylinder or a sp
3、ecial cylinder preparation. An alternative to the sampling system and procedure is available as “Closed Sampling System”, UOP, PIC. If the sample is to be transported offsite, see NOTE 1. OUTLINE OF METHOD Cylinder cleaning and sampling techniques are specified to obtain a representative, air-free s
4、ample in a suitable container, e.g., a double-valved, stainless steel cylinder. For trace sulfur or other heteroatom compound analysis, a Silcosteelcoated cylinder is preferred. When coated cylinders are unavailable or impractical, a conventional cylinder is treated (pickled) to make it more stable
5、to sulfur compounds. The clean, leak-free cylinder is mounted vertically near the sampling point and connected to the plant sample line by steel tubing or pipe. The connecting lines are flushed with the sample. After line flushing, the sample is allowed to flow upward through the cylinder. Several v
6、olumes of sample are discarded before closing the valves of the cylinder. The cylinders that are used for collection are constructed to provide safe outage. APPARATUS References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used, unless sta
7、ted otherwise. Cylinder, C3-C4fractions, type 304 stainless steel, high pressure, 12,400 kPa, gauge (1800 psig) maximum working pressure, one-liter capacity, Whitey, Cat. No. 304L-HDF4-1000, or equivalent. Equip the cylinder with outage tube, Whitey, Cat. No. 304L-DTM4-F4-038, two stainless steel va
8、lves, Whitey, Cat. No. SS-16DKM4-F4, and two plugs, Whitey, Cat. No. SS-4-P, or equivalent. Smaller cylinders, such as 500-mL, may be used when large quantities of sample are not required. IT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TO DETERMINE THE APPLICABIL
9、ITY 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 PRESCRIBED HEREIN CAN BE HAZARDOUS. MATERIAL SAFETY DATA SHEETS (MSDS) OR EXPERIMENTAL MATERIAL SAFETY DATA SHEETS (EMSD
10、S) FOR ALL OF THE MATERIALS USED IN THIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTION EQUIPMENT (PPE). COPYRIGHT 1966,1983,1987, 2000 UOP LLC ALL RIGHTS RESERVED UOP Methods are available through ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consho
11、hocken PA 19428-2959, United States. The 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. 2 of 12 516-00 Cylinder, C3-C4fractions, Silcosteel coated, for trace sulfur and other applications
12、which require a more inert surface than stainless steel, 1000 mL, Restek, Cat. No. 24275. Equip the cylinder with two Silcosteel coated valves, Restek, Cat. No. 24278, an outage tube, Whitey, Cat. No. 304L-DTM4-F4-038, and two caps, Whitey, Cat. No. SS-4-CP. Ship the outage tube to Restek for Silcos
13、teel coating, Restek, Cat. No. 54852. Caustic materials and strong acids will damage the Silcosteel surface. Samples and cleaning procedures must be caustic and acid free. Cylinder, gasoline and distillate fuels, type 304 stainless steel, 690 kPa, gauge (100 psig) maximum working pressure, Code No.
14、2, 28-L (7-gal) capacity, with dip tubes, equipped with 2 stainless steel valves. The cylinder without valves is available from Alloy Products, or equivalent. Valves are available from Whitey, Cat. No. SS-1KF4, or equivalent. The cylinder, as received, will be equipped with a long dip tube; the shor
15、t dip tube, made from 1/4-inch OD stainless steel, must be fabricated and welded to the valve coupling extending into the cylinder approximately 14 cm. Air-free samples of gasoline or distillate fuel oils to be used for treating, oxidation or corrosion studies are typically taken in this cylinder. C
16、AUTION: This cylinder cannot be used for samples having a vapor pressure above 275 kPa, gauge (40 psig) at 21C (70F). Cylinder Sampling Assembly, see Fig. 3, required for sampling gasolines or distillates Fittings, pressure-rated tubing or pipe made of stainless steel for use as transfer and manifol
17、d lines with appropriate valves, tees and unions or couplings of these materials. CAUTION. Do not use brass, aluminum or copper pipe, tubing, valves, unions, ferrules, or couplings. Grounding cable, heavy gauge wire or cable connected to a water pipe or to a rod driven into the ground, according to
18、local codes, having a suitable spring clamp to attach it to the metal cylinder; necessary to prevent explosion due to static electricity. Oven, gravity convection, capable of maintaining 150C, Fisher Scientific, Cat. No. 13-247-650G Pail, polyethylene, 13-L capacity, Fisher Scientific, Cat. No. 03-6
19、87-10 Regulator, nitrogen, delivery pressure 345-4480 kPa, gauge (50-650 psig), Matheson, Model No. 2-580, or equivalent Regulator, nitrogen, two-stage, delivery pressure 28-690 kPa, gauge (4-100 psig), Matheson, Model No. 3104-580, or equivalent Thermometer, Fisher Scientific, Cat. No. 15-077-2B Va
20、cuum pump, of sufficient capacity to evacuate the cylinder to the extent that the cleaning solution may be drawn into the cylinder REAGENTS References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used. Acetone, 99.5% minimum purity, Fisher
21、 Scientific, Cat. No. A949SK-4 Ferric chloride, Fisher Scientific, Cat. No. I89-500 3 of 12 516-00 Hydrochloric acid, 1:1, Fisher Scientific, Cat. No. LC15130-3 Isooctane, 99.5%, low residue, Fisher Scientific, Cat. No. O-301-4 Leak detector, solution, Leak-Check, Alltech Associates, Cat. No. 2025,
22、or equivalent Methanol, 99.8% minimum purity, Fisher Scientific, Cat. No. A408SK-4 Methylene chloride, 99.9%, low residue, Fisher Scientific, Cat. No. D151-4 Nitrogen, 99.99% minimum purity Pentane, 99%, low residue, Fisher Scientific, Cat. No. P399SK-4 Pickling solution. Prepare by dissolving 10 0.
23、1 g of ferric chloride in one liter of 1:1 hydrochloric acid. Steam, local supply TAM(toluene-acetone-methanol) solution. To prepare, mix equal portions of toluene, acetone and methanol. TI(toluene-isooctane) solution. To prepare, mix equal portions of toluene and isooctane. Toluene, 99.8% minimum p
24、urity, Fisher Scientific, Cat. No. T290SK-4 Water, deionized or distilled Water, tap, hot PREPARATION OF APPARATUS Cleaning and Drying Cylinders Proper preparation and cleaning of sample cylinders is of paramount importance. In no case may an improperly cleaned cylinder be used as a sample container
25、. Clean and prepare cylinders as described. Cylinders for C3-C4Fractions A. Silcosteel Coated Stainless Steel, or Conventional Stainless Steel if No Sulfur or Other Heteroatom Analysis Is Required 1. Completely empty the cylinder of any residual material in a well ventilated area or fume hood. 2. If
26、 the cylinder contained aqueous material, partially fill the cylinder with deionized or distilled water, agitate and drain. Follow the same procedure with methanol. Dispose of all used cleaning solutions in an environmentally safe manner. 3. Partially fill the cylinder (about 1/4) with TI solution,
27、agitate and drain. Follow the same procedure sequentially with pentane, methylene chloride and methanol. 4 of 12 516-00 4. Connect one end of the cylinder to a nitrogen source. Connect a length of tubing to the other end to properly vent the cylinder when placed in an oven. 5. Start a flow of nitrog
28、en. 6. Place cylinder in an oven at 150C and purge with nitrogen for 1 hr. 7. Remove the cylinder from the oven and allow it to cool maintaining a slow flow of nitrogen. 8. Pressure check the cylinder by closing one of the valves and then filling the cylinder with nitrogen to a pressure of approxima
29、tely 2000 kPa, gauge (290 psig). 9. Close the other valve and disconnect from N2 line. Completely immerse the nitrogen-pressured cylinder in a bath of clean tap water and observe it for leaks during a 5-minute period. Leaking valves should be repaired or replaced before use. 10. Remove the cylinder
30、from the bath when it is judged to be free of leaks and dry the outside. 11. Release enough nitrogen from the cylinder to retain a pressure of about 260 kPa, gauge (38 psig). 12. Cap or plug the valves to prevent leakage or contamination of the valve connection prior to use. The cylinder is ready fo
31、r sampling or shipment. B. Conventional Stainless Steel for Sulfur or Other Heteroatom Containing Sample Analysis Cylinders that are to be used for samples on which a sulfur analysis is to be performed must be treated with a special “pickling” technique, after they have been cleaned as described abo
32、ve. 1. Connect a 15-cm (6-inch) length of stainless steel tubing to one of the 2 valves on a previously cleaned cylinder. 2. Vent the cylinder, evacuate it for 15 minutes with a vacuum pump and close both valves. 3. Partially open the bottom valve and draw enough pickling solution into the cylinder
33、through the 15-cm length of tubing to equal about one-half the volume of the cylinder. 4. Close the bottom valve and remove the length of tubing from the cylinder. 5. Open the top valve and immerse the cylinder vertically in a pail of tap water at 54-60C (130-140F) for 30 minutes, leaving the upper
34、valve open. (CAUTION: A pressure buildup will occur in the cylinder during the pickling operation if both valves are closed.) Maintain the water temperature at 54-60C by occasionally adding hot tap water. 6. Close the upper valve, invert the cylinder, open the other valve and allow the cylinder to s
35、oak for another 30-minute period at 54-60C. 7. Remove the cylinder from the hot water bath and drain the pickling solution from the cylinder by opening both valves. Do not reuse the pickling solution. Dispose of all used cleaning solutions in an environmentally safe manner. 5 of 12 516-00 8. Flush t
36、he cylinder for approximately 1/2 hour with hot tap water and drain as completely as possible. 9. Rinse with deionized or distilled water. 10. Place the cylinder in an oven at 150C with both valves open for approximately 30 minutes. 11. Remove the cylinder and purge with nitrogen for 30 minutes or u
37、ntil cool. 12. Pressure check and prepare the cylinder for sampling as previously described in Steps 8 - 12, Silcosteel Coated Stainless Steel, or Conventional Stainless Steel if No Sulfur or Other Heteroatom Analysis Is Required. Cylinders (28-L) for Gasolines and Distillate Fuels 1. Remove the val
38、ve fitting connected to the short dip-tube. 2. Empty the cylinder of any residual material in a well ventilated area or fume hood. 3. Introduce steam into the cylinder through the valve on the long dip-tube and allow steam to flow through the cylinder for a period of approximately 24 hours. 4. Shut
39、off the steam and allow the cylinder to cool. 5. Drain as much water as possible through the short dip-tube opening. 6. Add approximately one liter of TAM solution through the short dip-tube opening and replace the valve fitting. 7. Agitate or roll the cylinder for several minutes. 8. Remove the val
40、ve fitting and drain the solvent through the short dip-tube opening. 9. Add approximately one liter of acetone to the cylinder through the short dip-tube opening. 10. Agitate, drain and repeat with a second acetone wash. 11. Wash the cylinder with one liter of methanol. 12. Drain as much methanol fr
41、om the cylinder as possible. 13. Blow dry with nitrogen for three to five minutes to remove all traces of methanol. 14. Install the valve fitting connected to the short dip-tube and flush the cylinder with nitrogen for 10 minutes to remove residual air or solvent. 15. Pressure the cylinder to 260 kP
42、a, gauge (38 psig) using nitrogen. 16. Check for leaks with a leak detector solution. 17. Allow the cylinder to stand overnight and check if a pressure drop has occurred. 18. Confirm the absence of leaks. 19. Cap or plug the valves to prevent contamination of the valve connection prior to use. 6 of
43、12 516-00 PROCEDURE Selection and Arrangement of Sampling Connections The sampling line tap should, preferably, extend into the plant transfer line, whether vertical or horizontal, so that the sample will be drawn from the center of the stream. The sampling line should be as short as possible. Const
44、ruct a sampling manifold assembly as shown in Fig. 1 when C3-C4fractions are to be sampled. The cylinder sampling manifold is of small-diameter stainless steel pipe or tubing, as compact as possible, and is mounted at the sample tap in a vertical position, as shown in the illustration. Do not use al
45、uminum, copper or brass tubing, pipe, valves, unions or couplings in the sampling system assembly. Arrange the cylinder to be used for sampling of gasoline and distillate fuels as shown in Fig. 2, utilizing the cylinder sampling assembly (Fig. 3) that is shipped with the cylinder. Every effort shoul
46、d be made to tap the plant transfer line at a point where the product temperature is less than 38C (100F), and the pressure is less than 310 kPa, gauge (45 psig). Sampling General It is best to obtain the sample from a vertical line as shown in the illustrations. If the sample must be taken from a h
47、orizontal line, modify the sampling manifold so that the cylinder will be in a vertical position. C3 - C4Fractions The clean, dry cylinder will be received for sampling under about 260 kPa, gauge (38 psig) of nitrogen pressure. 1. Mount the cylinder vertically as illustrated in Fig. 1 with both valv
48、es closed and secure it by a brace, K. 2. Connect a grounding cable to the cylinder. CAUTION: The grounding cable is necessary to prevent explosion due to static electricity. The grounding cable is connected to a water pipe or to a rod driven into the ground, according to local codes. 3. Attach the
49、manifold assembly to the sample line with a suitable connection, N, and to the sample cylinder with a suitable connection, M. 4. Connect a piece of pipe to cylinder valve, C, with a connector, L, to direct the flow of sample to a suitable stack or exhaust system. 5. Open valve S fully and let P reach the pressure of the plant transfer line. 6. Open A fully. Adjust D to flush the sampling line thoroughly until liquid flows freely through D. 7. Close D and partially open C. 8. Slowly open B. Flush the cylinder with several volumes of sample. 7 of 12 516-00 9. Close C,
