UOP 614-2002 HEPTANE-INSOLUBLE MATTER IN PETROLEUM OILS USING A MEMBRANE FILTER.pdf

1、 COPYRIGHT UOP LLC 1968, 1980, 2002 ALL RIGHTS RESERVED Marks of other proprietors may appear incidentally in this method for purposes such as product or service identification, but no claim is made to any other proprietors mark used. UOP Methods are available through ASTM International, 100 Barr Ha

2、rbor Drive, PO Box C700, West Conshohocken, 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). IT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRE

3、CAUTIONARY 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 PRESCRIBED HEREIN CAN BE HAZARDOUS. MATERIAL SAFETY DATA SHEETS (MSD

4、S) OR EXPERIMENTAL MATERIAL SAFETY DATA SHEETS (EMSDS) FOR ALL OF THE MATERIALS USED IN THIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTION EQUIPMENT (PPE). HEPTANE-INSOLUBLE MATTER IN PETROLEUM OILS USING A MEMBRANE FILTER UOP Method 614-02 SCOPE This method is fo

5、r the determination of heptane-insolubles in petroleum oils and is applicable to samples that are fluid at about 80C. This method covers the range of 0.01 to about 20 mass-% heptane-insolubles. Solid particulate materials interfere. The method may also be used to determine toluene-insolubles (see No

6、te 1). More viscous or solid materials such as asphalts may be handled by the modification described in the APPENDIX. The data provided by this method may be used as an index to coking tendency of petroleum oils when considering their suitability as charge stocks to cracking or other processes. OUTL

7、INE OF METHOD A weighed sample is dispersed in ambient temperature n-heptane, digested at 80C, and filtered through a weighed membrane filter. Samples that cannot be completely dispersed cannot be analyzed. The membrane filter is dried and reweighed to obtain the weight of insoluble matter. DEFINITI

8、ON Asphaltenes are defined as the material present in oil fractions that is not soluble in light paraffinic solvents. They are fine, powdery, black-brown solids and are polymeric materials spanning a wide range of molecular weights. Their chemical composition is quite complicated. They appear to be

9、closely associated with high molecular weight semi-polar naphthenic materials that require extended digestion time for separation. The terms “heptane-insolubles“ and “asphaltenes“ are often used synonymously. 2 of 10 614-02 APPARATUS (see also APPENDIX) References to catalog numbers and suppliers ar

10、e included as a convenience to the method user. Other suppliers may be used, unless stated otherwise. Balance, readability 0.1-mg Brush, antistatic, for balance, Fisher Scientific, Cat. No., 02-203 Clamps, for 250-mL flasks in shaker bath, Fisher Scientific, Cat. No. 15-455-15E Cylinder, graduated,

11、250-mL Desiccator, to hold Petri dishes Dishes, Petri, borosilicate glass, 60-mm diameter Filter holder, stainless steel, “Millipore Hydrosol“ filter holder, Millipore Corp., No. XX 20 047 20 Flask, filtering, with sidearm, 2-L, Fisher Scientific, Cat No. K953760-2000 Flask, Erlenmeyer, narrow neck,

12、 250-mL, with pennyhead, ground-glass, standard taper stopper, Fisher Scientific, Cat No. 10-100E Forceps, stainless steel, with flat, polished tips for handling filters, Millipore No. XX62 000 06 Gloves, cotton Oven, capable of operation at 95C Pipet, volumetric transfer, 2-mL, Fisher Scientific, C

13、at. No. 13-650-2C. Cut 4-5 mm off the tip to obtain a large-bore tip. Pipet, 25-mL graduated serological, large tip opening, Fisher Scientific, Cat. No. 13-671-108E Pipet filler, Fisher Scientific, Cat. No. 03-692-35 Pump, vacuum, Welch Directorr Direct Drive Pump, Fisher Scientific, Cat. No. 01-115

14、-4 Shaker water bath, Precision Scientific Model 50, Fisher Scientific, Cat. No. 15-455-5 Ultrasonic bath, 9-L capacity, 185 watt, Fisher Scientific, Cat. No. 15-335-110 Wash Bottle, 500mL, fluorinated HDPE, Fisher Scientific, Cat. No. 03-409-17B 3 of 10 614-02 REAGENTS AND MATERIALS (see also APPEN

15、DIX) References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used, unless stated otherwise. Aluminum foil, local supply Depth filter disc, 35-mm diameter, Millipore AP25 (see Note 2) Dessicant, indicating Drierite, Fisher Scientific, Cat.

16、No. 07-578-3A n-Heptane, 99% minimum purity, Acros Organics, Cat. No. 12034-0010, Fisher Scientific Membrane filter discs, 0.8 m and 5.0 m pore sizes, 47-mm diameter, white, plain, MF-Millipore SAMPLING Samples for this test should be taken in clean containers under a blanket of inert gas. The conta

17、iner should be filled only about 3/4 full so that the sample can be shaken vigorously before testing. No other tests or analyses should be made on this sample until after the heptane-insoluble content is determined. Samples under an inert gas blanket can usually be kept a few days at room temperatur

18、e. However, for best results, test the sample the same day it is taken. SAMPLING PROCEDURE The sampling procedure varies according to two conditions: the expected heptane-insoluble matter content and the fluidity of the sample. If the sample is sufficiently fluid to withdraw into a pipet, take the s

19、ample from the container at room temperature. If the sample is too viscous, or is waxy, it must be heated. 1. Loosen the cap or stopper of the sample container to vent it and place it in the 95C oven along with the appropriate pipet. 2. Heat small bottles (pint or less) 30 minutes before sampling. A

20、llow one hour of heating for a gallon container. Never heat for more than about 2 hours, because some oils form more insolubles on prolonged heating (see Note 3). Very high boiling samples, such as asphalts, should be sampled as described in the APPENDIX. The size of the sample taken for the test an

21、d the size of the pores of the membrane filter disc to be used are determined by the expected content of insolubles in the sample. If the insolubles content is expected to be less than 1.0 mass-% use the 25-mL graduated pipet with the large tip opening to take about 12-13 mL (approximately 10 g) of

22、sample. The 0.8 m pore size filter disc is used for filtering. If the insolubles content is expected to be above 1.0 mass-%, use the tipless 2-mL pipet to take a 0.5-1.5 g sample (Table 1) and use the 5.0 m filter for filtering. 4 of 10 614-02 Table 1 Sample Size and Filter Selection Range of Heptan

23、e-Insoluble Matter, mass-% Approx. Sample Size, g Filter Pore Size, m 0.01-1.0 1-5 5-20 10 1.5 0.5 0.8 5.0 5.0 PROCEDURE 1. Weigh a 250-mL Erlenmeyer flask to the nearest 0.0001 g. 2. Tighten the stopper or cap on the sample container and shake the sample vigorously for 30-50 seconds. 3. Quickly rem

24、ove the stopper or cap. 4. Insert the end of the pipet into the center of the oil, and draw a sample. Drain the pipet into the flask. Avoid getting sample on the groundglass joint. Use gloves if the sample is hot. 5. Allow the flask to come to room temperature and reweigh it to the nearest 0.0001 g.

25、 6. Add 200 mL of cool (room temperature) n-heptane to the flask. Stopper and shake the flask vigorously for at least 2 minutes. 7. Place the flask, loosely stoppered, in the ultrasonic bath for 5 minutes. Observe the bottom of the flask; there should be no sample left clinging to the bottom. If the

26、 sample is not completely dispersed, place the flask in the ultrasonic bath for an additional 5 minutes. Continue this procedure until the sample appears to be completely dispersed. The sample must be thoroughly dispersed or the test is invalid. All subsequent steps involving heated heptane shall be

27、 performed in a fume hood. 8. Place the loosely stoppered flask in the shaker water bath maintained at 80C. Operate the shaker at the maximum rate possible without splashing. Observe the sample several times over a period of 15 minutes. If the sample tends to settle out, place the flask in the ultra

28、sonic bath and redisperse the sample. Viscous samples may require extended heating and shaking time in the water bath with intermittent ultrasonic treatment to obtain complete dispersal of the sample. 9. Leave the flask in the shaker water bath for minimum of 60 minutes total digestion time at 80C.

29、Operate the shaker at the maximum rate possible, without splashing, during the entire digestion period (see Note 4). 5 of 10 614-02 10. Place a membrane filter disc in a clean, dry, previously numbered, Petri dish and weigh it to the nearest 0.0001 g. Always handle the filter discs with smooth-tippe

30、d forceps. 11. Insert a fan-shaped strip of aluminum foil into the filter flask with the narrow tail of the strip projecting out of the flask. The foil should reach to the bottom of the flask so that the filtrate will impinge-upon it. 12. Insert the base of the filter holder in the filtering flask.

31、13. Place the filter disc on the screen in the base of the filter holder. 14. Attach the top (funnel) of the filter holder and screw it on tightly. 15. Ground both the top and the base of the filter holder as well as the aluminum foil in the flask to a suitable common ground. The apparatus must be g

32、rounded in this fashion to prevent an electrostatic charge from accumulating on the filter cake. 16. Apply a slight vacuum to the filter (see Note 5). 17. Remove the flask containing the sample from the water bath. Wipe the water from the outside of the flask. 18. Stopper and shake the flask, then p

33、our the contents on the filter. If the amount of insoluble material is high, pour the contents on the filter in aliquots. When the level of the solution has receded to the throat of the funnel, rinse the flask at least 3 times, using 100 mL of hot (about 80C) heptane the first time, and 50-mL portio

34、ns subsequently, pouring the washings down the sides of the funnel to wash any sediment onto the filter. The last wash should be colorless; if it is not, continue washing until the washings are colorless. CAUTION: Heptane has a low flash point. KEEP AWAY FROM OPEN FLAMES. 19. Rinse, with about 100 m

35、L of hot heptane, the sides of the funnel and filter cake until the solids on the filter appear to be dry (see Note 6). 20. Unscrew the filter holder and gently remove the funnel. If the sediment is unusually heavy (greater than 40-50 mg) some of it may tend to cling to the throat of the funnel at t

36、he bottom where it meets the filter. Wash this material onto the filter. 21. Examine the filter disc. The outer edge should be only lightly discolored if it was properly gripped by the holder. Wash the edge of the filter disc with a fine stream of hot heptane to remove any oil that may have seeped u

37、nder the edge of the holder until the filter appears dry. 22. Disconnect the vacuum line. Hold the Petri dish in which the disc was originally weighed next to and level with the filter. Gently loosen the filter supporting the heptane-insolubles with the tip of the forceps and carefully slide it into

38、 the dish. 23. Discard the filtrate. 24. Place the dish containing the filter in the oven at 95C and heat 10 to 15 minutes. 6 of 10 614-02 S)TG(100 25. Remove the dish and filter, and cool in a desiccator to prevent the filter cake from absorbing moisture, about one hour. 26. Reweigh to the nearest

39、0.1 mg (see Note 7). CALCULATIONS Calculate the concentration of heptane insolubles using the Equation. where: G = gross weight of dish, filter and residue, g S = weight of sample, g T = tare weight of dish and filter, g For values less then 0.10 mass-%, report to three decimal places. For values fr

40、om 0.10 to 10.0 mass-%, report to two decimal places. For values 10.0 mass-% and higher, report to one decimal place. NOTES AND PRECAUTIONS 1. All test conditions are identical when determining toluene-insolubles except that toluene is used as a solvent and 5 m Teflon (PTFE) membrane filters are use

41、d for filtering. Precision for this modification has not been established. 2. The depth filter disc is used with black oil samples, which tend to plug the regular filter. The depth filter is weighed along with the regular filter and then placed in the throat of the funnel after the regular filter is

42、 in place. The analysis then continues as described in the method using both filters. 3. Many waxy or viscous materials can be safely heated prior to transferring the desired amount into the flask. However, prolonged or overheating can often cause oxidative or thermal polymerization of asphaltene pr

43、ecursors that result in a higher insolubles content. 4. The importance of proper dispersion, the correct digestion time and continuous shaking cannot be overemphasized. Digestion time cannot be reduced by raising the bath temperature above 80C because samples tend to scorch if overheated, thereby in

44、creasing the asphaltene content. 5. Do not use more vacuum than what is absolutely necessary because evaporation of solvent and consequent chilling of the mixture may occur and cause the wax to precipitate. 6. Rinsing the funnel is best done by using a wash bottle containing hot heptane. When in dou

45、bt, use plenty of hot heptane. Do not allow the filter cake to become dry when rinsing as cracks may develop. n-Heptane will flow through the cracks and not through the filter cake. This incomplete washing could cause high results. Heptane-Insoluble Matter, mass-% = 7 of 10 614-02 7. Vacuum tower bo

46、ttoms may contain fine sand particles. These will show on the filter as minute, glittering specks. Report their presence. PRECISION Precision statements were determined using UOP Method 999. ASTM and UOP Repeatability A nested design was carried out for determining n-heptane insolubles at 0.007 and

47、0.020 mass-% with two analysts in one laboratory. Each analyst carried out tests on two days, performing two tests at two levels each day. The total number of tests was 16. The precision data are summarized in Table 2. Two tests performed by the same analyst on the same day should not differ by more

48、 than the ASTM allowable difference with 95% confidence. Two tests performed in one laboratory by different analysts on different days should not differ by more than the UOP allowable difference with 95% confidence. The ASTM repeatability data at the higher levels of n-heptane insolubles were previo

49、usly obtained for UOP 614-80, with 6, 5, and 8 replicates for the insolubles ranging from 0.13 to 12.4 mass-%. The data in Table 2 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. Table 2 ASTM and UOP Repeatability, mass-% ASTM Repeatability UOP Repeatability1 Sample Mean Level Within-Day esd Allowable Difference Within-Lab esd Allowable Difference 1 0.007 0.00071 0.0028 0.0016 0.006 2 0.020 0.0012 0.005 0.005