1、Ref. No. DIN 51595 : 2000-11English price group 05 Sales No. 010508.02DEUTSCHE NORM November 200051595Continued on pages 2 to 6. No part of this translation may be reproduced without the prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has
2、the exclusive right of sale for German Standards (DIN-Normen).Determination of asphaltene content ofpetroleum products by precipitation in heptaneTranslation by DIN-Sprachendienst.In case of doubt, the German-language original should be consulted as the authoritative text.ICS 75.080; 75.100Prfung vo
3、n Minerallerzeugnissen Bestimmung des Gehalts anAsphaltenen Fllung mit HeptanIn keeping with current practice in standards published by the International Organization for Standardization(ISO), a comma has been used throughout as the decimal marker.All dimensions are in millimetres.ForewordThis stand
4、ard has been prepared by Technical Committee Prfung von Schmierlen, sonstigen len undParaffinen and Prfung von flssigen Kraftstoffen und Heizlen of the Fachausschuss Minerall- und Brenn-stoffnormung of the Normenausschuss Materialprfung (Material Standards Testing Committee). It con-forms in substan
5、ce to IP 143/96, but differs in the following respects:a) a DIN 12785 BST 1/-2/300 thermometer instead of the IP thermometer is used in distilling the lightcrude oil fractions;b) different precision values have been specified;c) the method is checked using a calibrating oil.AmendmentsThis standard d
6、iffers from the December 1978 edition as follows:a) the heat treatment times have been extended from 30 minutes to 45 minutes;b) cleaning agents other than sulfuric acid are permitted;c) clause 10 has been added;d) the standard has been editorially revised and references updated.Previous editionsDIN
7、 DVM 3660 = DIN 53660: 1932-11; DIN 51557: 1955x-02, 1957-03, 1959-01;DIN 51595: 1968-02, 1971-02, 1973-10, 1978-12.1 ScopeThe method specified in this standard serves to determine the asphaltene content of petroleum productsnot containing additives, bitumen and crude oil from which the low-boiling
8、fractions up to an oil temperatureof 260 C have been removed by distillation. The asphaltene content is indicative of the behaviour ofpetroleum products in practice. A high asphaltene content may result in unwanted bituminous precipitates.NOTE: Petroleum products containing additives may give errone
9、ous results.Supersedes December 1978edition.Page 2DIN 51595 : 2000-112 Normative referencesThis standard incorporates, by dated or undated reference, provisions from other publications. These norma-tive references are cited at the appropriate places in the text, and the titles of the publications ar
10、e listed below.For dated references, subsequent amendments to or revisions of any of these publications apply to thisstandard only when incorporated in it by amendment or revision. For undated references, the latest edition ofthe publication referred to applies.DIN 1333 Presentation of numerical dat
11、aDIN 12245 Rough or ground 1:10 conical sockets and cones for laboratory useDIN 12252 Conical ground glass stoppers for laboratory useDIN 12336 Flat bottom glass evaporating dishes for laboratory useDIN 12348 Round bottom and flat bottom flasks fitted with 1:10 tapered socket for laboratory useDIN 1
12、2387 Conical flasks for laboratory useDIN 12445 Short-stem funnels for laboratory useDIN 12448 Filter paper for laboratory useDIN 12491 Vacuum desiccators for laboratory useDIN 12581 Allihn condensers with conical ground joints for laboratory useDIN 12785 Laboratory thermometers for particular appli
13、cationsDIN 50011-11 Artificial climates in technical applications Controlled-atmosphere test installations General concepts and requirementsDIN 50011-12 Artificial climates in technical applications Air temperature as a climatological quantity incontrolled-atmosphere test installationsDIN 51633 Benz
14、ene and benzene homologues RequirementsDIN 51750-1 Sampling of petroleum products GeneralDIN 51750-2 Sampling of liquid petroleum productsDIN 51750-3 Sampling of pasty and solid petroleum productsDIN 51751 Determination of distillation characteristics of liquid petroleum productsDIN EN ISO 4259 Petr
15、oleum products Determination and application of precision data in relation to methodsof test (ISO 4259 : 1992 + Corr 1 : 1993)IP 143/96 Determination of asphaltenes (heptane insolubles) in crude petroleum and petroleum prod-ucts1)3 ConceptAsphaltenesConstituents of crude oil that are insoluble in he
16、ptane, but soluble in pure toluene.4 UnitThe unit used to express the asphaltene content is g/100 g, reported as a percentage by mass.5 PrincipleA sample is dissolved in 30 times its volume of heptane and the solution is allowed to stand at ambienttemperature. The precipitated and undissolved compon
17、ents are removed by filtering through a filter paper. Afterother paraffin components have been removed from the filter paper and residue by extraction with boilingheptane, the asphaltenes left on the filter paper are dissolved in boiling pure toluene and determined gravimetri-cally after evaporating
18、 the toluene.6 ApparatusIn addition to standard laboratory equipment, the following shall be used.6.1 Extractor, comprising the following components:6.1.1 DIN 12387 E 500 ANS 29 conical flask or DIN 12348 RANS 250-29 round bottom flask;6.1.2 DIN 12581 K 250-29 condenser;1) Issued by the Institute of
19、 Petroleum (IP), London, GB.Page 3DIN 51595 : 2000-116.1.3 extractor as shown in figure 1;6.1.4 DIN 12252 ANS 29/32 glass stopper for conical flasks.6.2 DIN 12445 70 funnel.6.3 DIN 12336 80 evaporating dish.6.4 DIN 12448 A 110 2c filter paper.6.5 Water bath and heater.6.6 Oven (as in DIN 50011-11 or
20、 DIN 50011-12), capable of maintaining temperatures of 110 C or more.6.7 Desiccator (as in DIN 12491), without desiccant;6.8 Distillation apparatus (as in DIN 51751), for preparing crude petroleum samples.6.9 DIN 12785 BST 1 /-2/300 thermometer.1 DIN 12245 A29/32 conical socket2 Opening with a diame
21、ter of 6 t 13 DIN 12245 B29/32 coneFigure 1: Extractor7 ReagentsThe following reagents shall be used.7.1 Analytical grade heptane.7.2 DIN 51633 B pure toluene.7.3 Concentrated sulfuric acid, r20= 1,84 g/ml.7.4 Chromic acid, prepared by dissolving 50 g of K2Cr2O7in one litre of sulfuric acid. The sol
22、ution shall bekept in flasks sealed with a ground glass stopper (see subclause 11.3 for alternative cleaning agents).7.5 Chemically pure acetone.8 SamplingSamples shall be collected as specified in DIN 51750-1, DIN 51750-2 or DIN 51750-3.Page 4DIN 51595 : 2000-112) Information on sources of supply i
23、s obtainable from Fachausschuss Minerall- und Brennstoffnormung,Kapstadtring 2, 22297 Hamburg, Germany.9 Preparations9.1 Preparation of crude oil samplesLight fractions that distil at temperatures up to 260 C shall be removed by distillation prior to analysis, sincethey may affect the precipitation
24、of asphaltenes. If this distillation is difficult because the water content is high,the crude oil may be dried either by centrifuging or by filtering through a suitable desiccant (e.g. anhydrouscalcium chloride, sodium sulfate).Weigh, to an accuracy of 0,1 g, 90 ml to 100 ml of sample into the disti
25、llation flask which has previously beenweighed and weigh again. Insert the thermometer so that its sensor is in the centre of the sample. Switch onthe distillation flask heating and, after the onset of boiling, adjust the heating so as to maintain a uniformdistillation rate of 2 ml/min to 2,5 ml/min
26、. Stop the distillation when the distillation residue reaches a tempera-ture of 260 C. Allow the residue to cool and determine its mass to the nearest 0,1 g.Determine the asphaltene content of the entire residue as described in clause 11.9.2 Preparation of bitumen samplesSamples of hard bitumen shal
27、l be ground to a powder immediately before analysis.9.3 Glassware cleaningBefore use, all glassware shall be carefully cleaned by immersion for not less than twelve hours in concentratedsulfuric acid or, preferably, in chromic acid. Acid-free, highly efficient and biologically degradable cleaningage
28、nts may be used instead of chromic acid2). After rinsing with distilled water and acetone, the glassware shallbe dried in an oven at a temperature of 100 C to 110 C for about 30 minutes and cooled in the desiccator(without desiccant) for about 45 minutes before weighing.10 Checking the methodTo chec
29、k the method, prepare a reference solution of DIN 51595 calibration substance ASP 28 having anasphaltene content of 28,5 % (m/m) in a spindle oil having a viscosity from 7 mm2/s to 25 mm2/s at 40 C. Mixthe reference solution by stirring for 90 minutes at 100 C and ensure that its asphaltene concentr
30、ation is similarto that of the concentration range to be tested.A difference between the test result obtained with the reference solution and the theoretical value that is lessthan or equal to the repeatability limit specified in the table below will confirm that the procedure conforms tothis standa
31、rd.If the test result differs by more than the reproducibility limit, R, divided by 32 from the theoretical value, preparea fresh reference solution and perform the check again. If the permissible difference is still exceeded, check theequipment and working conditions as described in this standard a
32、nd then repeat the check using the tworeference solutions.11 Procedure11.1 Weigh, to an accuracy of 0,001 g, a volume of sample not exceeding 10 g and sufficient to obtain a finalasphaltene mass not exceeding 0,25 g into a conical flask. Add 30 ml of heptane for every 1 g of sample andboil for one h
33、our under reflux. Then remove the conical flask and contents from the reflux condenser, seal it witha stopper and place it in a dark cupboard for 0,5 h to 2,5 h at ambient temperature.NOTE: The ratio of sample mass to heptane mass may be increased to 1:50 if bumping occurs as a result ofa high aspha
34、ltene content (greater than 25 % (m/m) while the sample is being boiled in heptane to dissolveit.11.2 Without shaking, decant the liquid through the filter paper folded as shown in figure 2 to prevent any lossdue to asphaltenes creeping up the sides. Also transfer the residue left in the conical fla
35、sk to the filter paperand rinse the flask several times with small amounts of hot heptane. Finally, rinse the flask walls again with hotheptane and filter the latter. Discard the heptane filtrate.Put aside the conical flask used to precipitate the asphaltenes, which shall no longer contain any oil,
36、and onlyuse it again for the extraction with pure toluene described in subclause 11.4.11.3 Transfer the filter paper and residue to the extractor, connect the latter to a fresh conical or round bottomflask containing about 50 ml of heptane, fit the reflux condenser and extract filter paper and resid
37、ue for onehour.2Page 5DIN 51595 : 2000-111 Paper clipFigure 2: Folded filter paperTo ensure complete extraction, make sure that the filter paper is wetted all over. Adjust the conical or roundbottom flask heater so that reflux takes place at two to four drops per second. Stop the extraction when a f
38、ewdrops of heptane from the extractor outlet leave no residue on a watch glass after evaporation. Discard theheptane extract.11.4 After extraction, switch off the extractor heater and replace the conical or round bottom flask by theprecipitation flask (see subclause 11.2). Add about 30 ml to 60 ml o
39、f pure toluene to the flask and extract underreflux as described in subclause 11.3 until all the asphaltenes on the filter paper have been dissolved. Thenswitch off the heater and remove the precipitation flask containing the solution of asphaltenes in pure toluene.11.5 Transfer the pure toluene sol
40、ution quantitatively to an evaporation dish which has previously beenweighed to an accuracy of 0,000 2 g. Rinse the precipitation flask several times with small amounts of hot puretoluene and add the rinsings to the evaporation dish. The total amount of pure toluene used for rinsing shall notexceed
41、30 ml. Place the dish containing pure toluene on a boiling water bath and evaporate the solvent.CAUTION. Evaporate the toluene in a well-ventilated fume cupboard. Take appropriate steps to preventlosses due to the bitumen solution sputtering (e.g. by covering the dish with a weighed watch glass).The
42、n dry the evaporating dish and residue for 45 minutes in an oven at a temperature of (115 t 5) C and reweighto an accuracy of 0,0002 g after cooling in the desiccator (cooling time being one hour). Subtract the mass ofthe empty evaporating dish to obtain the mass of asphaltenes.The mass of the evapo
43、rating dish may decrease when it is heated in the water bath. Treat an empty dish in thesame way to determine this loss in mass (evaporating dish blank) and always correct the mass of the evapo-rating dish used in the gravimetric determination by the change in mass of the empty evaporating dish. Ens
44、urethat the evaporating, drying and cooling times are the same for the empty dish as for that used for analysis.Since asphaltenes are very susceptible to oxidation, it is necessary to adhere strictly to the drying and coolingtimes and temperatures specified.12 Expression of resultsThe asphaltene con
45、tent shall be reported, with a reference to this standard, as a percentage by mass, to thenearest 0,01 % for contents ranging from 0,05 % to 1,0 % and to the nearest 0,1 % for contents exceeding 1 %.Below 0,05 %, the result shall be reported as below 0,05 % or no detectable amount.DIN 1333 shall be
46、taken into account when rounding to the last significant place.13 Precision(see DIN EN ISO 4259)The following criteria shall be used to assess the precision.Page 6DIN 51595 : 2000-11Repeatability limit(same operator, same equipment)The absolute difference between successive results obtained under re
47、peatability conditions will not exceed therepeatability limit, r, given in the table below in more than 5 % of cases (if the testing is performed in accordancewith this standard).Reproducibility limit(different operators, different equipment)The absolute difference between two single results obtaine
48、d under reproducibility conditions will not exceedthe reproducibility limit, R, given in the table below in more than 5 % of cases (if testing is performed inaccordance with this standard).Asphaltene content, Repeatability limit, r, as a Reproducibility, R, as aas a percentage percentage of mean of results percentage of mean of resultsBelow 0,05 *) *)0,05 to 0,5 30 30Above 0,5 up to 2 10 20Above 2 10 15*) No information can be given about precision for asphaltene contents below 0,05 % (m/m).
