UOP 79-1987 FRACTIONATION OF PETROLEUM DISTILLATES.pdf

1、 COPYRIGHT 1968, 1987 UOP LLCALL RIGHTS RESERVEDUOP Methods are available through ASTM International, 100 Barr Harbor 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 atserviceastm

2、org, 610.832.9555 FAX, or 610.832.9585 PHONE.FRACTIONATION OF PETROLEUM DISTILLATESUOP Method 79-87SCOPEThis method describes equipment and procedures used for laboratory fractionation of petroleumdistillates and products. Procedures are given for quantitatively removing non-condensable and condens

3、ablegases, as well as obtaining liquid fractions boiling within the range of 10 to 400 C. For the fractionation ofcrude oil and the preparation of distillation curves from true boiling point (TBP) data, see ASTM D 2892.OUTLINE OF METHODA known mass of a petroleum distillate or product is fractionate

4、d in a high efficiency laboratory column.Procedures are given for the quantitative separation of normally gaseous hydrocarbons, such as C3and/or C4hydrocarbons from C5and heavier fractions, and for the precision fractionation at atmospheric and reducedpressures of normally liquid hydrocarbons. Proce

5、dures for the collection of gas/liquid samples for sulfurdeterminations are also included.APPARATUSBalance, top-loading, 0 - 30,000 g, readability 0.1-g, Sartorius, Model 3808 MP8, Sargent-WelchScientific, Cat. No. S-2714-21A, or equivalentBarometer, mercurial, Sargent-Welch Scientific, Cat. No. S-4

6、565, or equivalentCylinder, graduated, 2000-mLCylinders, type 304 stainless steel, high pressure, 12,400 kPa (1800 psig) maximum working pressure,75- and 1000-mL capacity, Whitey Co., Cat. Nos. 304L-HDF4-75 and 304L-HDF4-1000, respectively,or equivalent. Equip each cylinder with 2 valves, Whitey Co.

7、 Cat. No. 16DKM4-F4, or equivalent, anda hose fitting, Matheson, Cat. No. 121M, or equivalent.Density meter, and support apparatus, as specified in ASTM D 4052 (optional)Flasks, Dewar, 350- and 1000-mL capacities, Sargent-Welch Scientific, Cat. No. S-34707-AA and B, orequivalentFractionating system

8、 (Figs. 1 - 4), Reliance Glass Works Inc., or equivalent, consisting of the following:IT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TODETERMINE THE APPLICABILITY OF REGULATORY LIMITATIONS PRIOR TO USE. EFFECTIVE HEALTH ANDSAFETY PRACTICES ARE TO BE FOLLOWED WHEN

9、 UTILIZING THIS PROCEDURE. FAILURE TO UTILIZE THISPROCEDURE IN THE MANNER PRESCRIBED HEREIN CAN BE HAZARDOUS. MATERIAL SAFETY DATA SHEETS(MSDS) OR EXPERIMENTAL MATERIAL SAFETY DATA SHEETS (EMSDS) FOR ALL OF THE MATERIALS USED INTHIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSO

10、NAL PROTECTIONEQUIPMENT (PPE).2 of 1879-87Flasks, distillation, round bottom, ranging in capacity from 200- to 5000-mL, equipped with a stopcockin the sidearm, a thermowell, and a 50/30 female spherical glass jointFractionating column, Podbielniak HYPER-CAL, 30-mm ID x 1.2 m, Cat. No. 3438, containi

11、ng a one-meter section of HELI-PAK column packing, Cat. No. 3008. The use of O-ring joints isrecommended wherever possible to avoid contamination from the lubricating grease. The overallheight of the assembled system is 2.2 m.Gauge, McLeod, 0 - 15-mm. A pressure transducer, including power supply an

12、d digital readout, maybe substituted.Heating mantles, “Glas-Col” mantles, in sizes corresponding to those of the distillation flasksLight overhead condenser (Fig. 2). This is an external condenser which is filled with dry ice whenrefluxing propane and butane prior to debutanization of a gasoline.Man

13、ometers, open-arm typeManostatPotentiometer, 0 to 500 C rangeReceivers, jacketed and unjacketed, calibrated for accurate measurement of fraction volumesRefrigeration unit and pump, capable of circulating an ethylene glycol-water mixture through thereflux condensers at approximately -20 C (-4 F)Surge

14、 tankThermocouples, calibrated, iron-constantan wireTime switchVacuum pumpGas condensate traps, 100- and 300-mL capacity, UOP Inc., or equivalentGas sampling bottle, 2 required, 8-L, aspirator type (Fig. 5), UOP Inc., or equivalentHydrometers, petroleum, and support apparatus, as specified in ASTM D

15、 1298Regulator, nitrogen, two-stage, high purity, Matheson, Model 3104-580, or equivalentTubing, latex, translucent, heavy wall, 6.4-mm ID, 2.4-mm wall, Sargent-Welch Scientific, Cat. No. S-73571-D, or equivalentREAGENTS AND MATERIALSAll reagents shall conform to the specifications established by th

16、e Committee on Analytical Reagents ofthe American Chemical Society, when such specifications are available, unless otherwise specified.References to water mean deionized or distilled water.Acetone, 98% minimum purity3 of 1879-87Cleaning solution, Micro, International Products Corporation, or equival

17、entDry iceEthylene glycol, 98% minimum purityHydrochloric acid, concentratedMercury, triple distilledMethyl orange, powder, Sargent-Welch Scientific, Cat. No. EKC-432, or equivalentNitrogen, extra dry, 99.9% minimum puritySodium chloride, crystal, Sargent-Welch Scientific, Cat. No. SC-14767, or equi

18、valentSodium chloride solution, saturated and acidified. To prepare, place approximately 860 g of sodiumchloride in an 8-L gas sampling bottle. Add water to almost fill the bottle and shake or stir to dissolvethe sodium chloride. Add approximately 0.2 g of methyl orange, 5 drops of concentrated hydr

19、ochloricacid and shake or stir to mix.Stopcock grease, Dow-Corning High Vacuum Silicone Grease, Sargent-Welch Scientific, Cat. No. S-77324-01, or equivalentToluene, 99.9% minimum purityPREPARATION OF APPARATUSAssemble the apparatus appropriate to the fractionation desired, as shown in Figs. 1 - 4.Af

20、ter assembly, clean the column with suitable solvents and dry with a stream of nitrogen. Lubricate allstopcocks and ground-glass joints not equipped with O-rings with the specified grease.To check the apparatus for leaks, attach a flask to the spherical joint at the bottom of the column. Closethe sy

21、stem and attach a vacuum line to the flask at the stopcock. Evacuate the system to approximately 2 - 3mm Hg (0.27 - 0.40 kPa) absolute. Close the stopcock and detach the vacuum line. If the reading onManometer B remains constant over a period of 20 to 25 minutes, the apparatus may be considered leak

22、proof.Determine the accuracy of the thermocouple and potentiometer according to Paragraph A6 of ASTM D2892. Examine the flask and the condensate trap for cracks in the glass. Rinse with acetone and dry beforeuse. Clean glassware with cleaning solution whenever necessary.PROCEDUREBecause this method

23、 covers materials with such diverse boiling ranges, not all sections of the proceduremay be applicable to any one particular sample. Each section contains directions for assembly and shut-down so that it can be performed independently if required. Determine which sections are applicable to thesample

24、 to be fractionated. Follow the directions for assembly in the section where the fractionation begins,and the directions for shut-down in the section where the fractionation is concluded.4 of 1879-87Part I - Fractionation of Unstabilized SamplesIncluded in this category are fractionations at atmosph

25、eric pressure of unstabilized hydrocarbon samplesfor removal of C4and lighter components. The composition of these fractions may subsequently bedetermined by mass spectrometry, gas-liquid chromatography or an equivalent method. Unstabilizedhydrocarbon samples have a Reid vapor pressure of 15 psig (1

26、03 kPa) or greater as determined by ASTM D323, and are by necessity contained in stainless steel sample cylinders under pressure.A. Collection of Non-Condensable GasesAssemble the apparatus as shown in Fig. 1 and follow the procedure as specified under PREPARATIONOF APPARATUS. Weigh and record the m

27、ass of a clean flask to the nearest 0.1 g. Attach the flask to thespherical joint at the bottom of the column. The flask should be of proper size for the volume of sample tobe charged (not over 80% of the capacity of the flask), making due allowance for thermal expansion. Thestopcock on the side arm

28、 of the flask is used for sampling directly into an evacuated system.Weigh and record the mass of a clean gas condensate trap to the nearest 0.1 g. Pre-cool the trap byimmersion in a Dewar flask filled with a dry ice-acetone mixture. With a short piece of latex tubing, attachthe gas vent line to the

29、 coil end of the trap immersed in the cooling mixture. Pre-cool the ethylene glycolsolution and start circulation of the solution through the reflux condenser only.Fill an 8-L gas sampling bottle (Fig. 5) with sodium chloride solution. Prepare fresh sodium chloridesolution when the methyl orange ind

30、icator starts to fade from red-orange to yellow. Using latex tubing,attach stopcock B of the gas sampling bottle to the exit end of the gas condensate trap. Close stopcocks Aand B. Open stopcock D on the gas line vent. Evacuate the entire system to approximately 2 - 3 mm Hg(0.27 - 0.40 kPa) absolute

31、 Check the system for leaks.Set up a second bottle containing a known volume, typically 1000 mL, of sodium chloride solution.Attach a piece of latex tubing to stopcock E. Open stopcock E and carefully fill the tubing with solution.Attach the tubing to stopcock C of the gas collecting bottle.Weigh t

32、he sample cylinder and record the mass to the nearest 0.1 g. Cool the cylinder in a refrigerator orin a container filled with ice. Surround the distillation flask with dry ice and allow it to cool for 10 minutes.With the cylinder in a vertical position, connect the bottom value of the cylinder to th

33、e stopcock on the flaskwith a short piece of latex tubing. Open the stopcock. Carefully open the valve on the cylinder and adjustthe flow so that the sample will enter the flask slowly. When the column reaches a pressure of 50 mm (6.7kPa) above atmospheric, as indicated by Manometer B, open stopcock

34、 C at the bottom of the gas samplingbottle, and carefully open stopcock B between the trap and the bottle. Begin collecting the non-condensablegases by displacing the sodium chloride solution. Continually adjust the flow of the sample into the flaskand the non-condensable gas into the collecting bot

35、tle so that a positive pressure is maintained in thesystem. Continue charging until the entire contents of the cylinder are charged to the flask as evidenced by aloss of positive pressure. Close stopcock B. Close the valve on the cylinder.Replace the dry ice surrounding the flask with the mantle hea

36、ter. Allow the flask to warm to roomtemperature and turn on the mantle heater at the lowest setting. Slowly increase the rate of heat input untilthe sample begins to boil. Carefully open stopcock B when a positive pressure is re-established. Maintain apositive pressure in the system by opening and c

37、losing stopcock B as the pressure indicates until thepressure remains negative with stopcock B closed. At this point, all of the non-condensable gases have been5 of 1879-87separated from the sample and the remainder of the gas will condense in the trap. Close the stopcock on thedistillation flask. D

38、isconnect the gas bottle from the trap, leaving the trap connected to the column butvented to the atmosphere. Weigh the sample cylinder and record the mass to the nearest 0.1 g. Calculate themass of the charge.In order to adjust the pressure in the gas collecting bottle to atmospheric, raise or lowe

39、r the second bottleuntil the levels of the sodium chloride solution in the two bottles are equal. Close stopcocks C and E.Measure the height, in mm, of the solution left in the gas collecting bottle above the discharge point.Disconnect the second bottle and measure the volume of solution displaced.

40、From this volume subtract thevolume of solution that was originally in the bottle. Record this value as the uncorrected gas volume.Record the room temperature and the barometric pressure. Determine the mol-percent of each componentpresent in the non-condensable gas fraction by mass spectrometry, gas

41、liquid chromatography or equivalentmethod.If the volume of non-condensable gases exceeds the capacity of the gas-collecting bottle, the distillationwill have to be interrupted to change bottles. Close the valve on the cylinder. Return the distillation flask tothe dry ice bath, and follow the proced

42、ure in the preceding paragraph. Replace or refill the bottle, aftertaking a sample for analysis, and restart the distillation.B. Collection of Condensable Gases (Debutanization)Assemble the apparatus as shown in Fig. 2. Before the sample is charged add dry ice to the light oveheadcondenser. This wil

43、l help to establish a good condensable gas reflux in the column. It will also provide abetter separation between the C4and C5components and minimize the amount of C5and heaviercomponents distilled into the condensate trap. Once a good reflux is established in the column, as evidencedby a steady drip

44、 from the reflux condenser (3 - 4 drops per second), allow the dry ice in the light overheadcondenser to vaporize and do not add any more.Follow the procedure in Part I Section A to remove the non-condensable gases. Warm the sample aspreviously described. When all the non-condensable gases have been

45、 removed, and a good refluxestablished, turn on the time switch set to 30:1 (30 seconds off: 1 second on). The cold liquid reflux willpass into the warm receiver and vaporize. The gas vapors will be drawn into the gas condensate trap and becollected. Continue the distillation until the vapor tempera

46、ture reaches 10 C (50 F). Place the column ontotal reflux for 10 minutes by shutting off the time switch. If the vapor temperature drops more than 3degrees, resume the distillation until it increases to 10 C. Continue alternating between distillation and totalreflux until the vapor temperature stabi

47、lizes at 10 C for a minimum of 10 minutes. After stabilization isattained turn the time switch on again and distill to 15 C (59 F). Shut off the time switch. Cool thedistillation flask to 0 C (32 F) with ice. Disconnect the gas condensate trap from the apparatus. Remove thetrap from the Dewar and wi

48、pe it free of acetone and dry ice. Quickly weigh the trap and record the mass ofthe gas condensate fraction. Replace the trap containing the gas condensate fraction in the Dewar flask, addsufficient dry ice-acetone mixture to the Dewar flask to fill it and label the trap with the sampleidentificatio

49、n. Analyze the gas condensate, employing mass spectrometry, gas-liquid chromatography or anequivalent method.Weigh and record the mass of the debutanized bottoms. Determine the relative density of the bottomsfraction by ASTM D 1298. Store the debutanized bottoms in a labeled bottle in a refrigerator for furtheranalysis.6 of 1879-87Alternatively, follow the procedure for the fractionation and collection of the gas condensate, pentanesand subsequent fractions, if desired, as described for stabilized hydrocarbon samples (Part II).C. Preparation of Samples for Sulfur AnalysesTotal sulfur conten