Document RpRXL1n3Kmka91mkRnEMz90Qv

-Designation: D 96 68 Standard: 2642 Ammean National Standard 211.8-1969 American National Stenduds Inni(uco Mothod 3003-Fed.raI Tart Method Standard N o 791b DIN 51793 Standard Methods of Test for , WATER AND SEDIMENT IN CRUDE OILS' :I,,, Slllidr,d is issued under the fixed designation D 96; the number immcdiatcly following the designation indicates the ,I ungin~Al dopion or. in the case of revision, the )ear of last ccvtsion. A number in parcnthcacs Indicates the year of :,,, rrrnp,oral. This is also B standard of the American Petroleum Institute issued under the fined designation API 2542. :$m-th& vclc adapted tu a joint ASTM-API Standard in 1963. 1. .scope 1 . 1 These methods describe procedures for :he dctcrmination of water and sedimtnt in ciuttc oils. I.' The methods appear in the following mtcr: Sections Vfrftchtkdo,d\-.L.a.b.o..ra..to..ry....C..e.n.t.r.i.f.u.g.e... \!<!hid H-Field Czntrifugc Method .... 3 to 7 8 10 13 Urthod I:.-%-rnl \tt\hd C-Field Tube D-kC ...C..e.n..t.r.if.u.g..e...M.e..t.hod. Method ............. 14 10 19 20 to 22 1.3 'The Gravity Settling Method for Crude ihh is in use in sbme areas of the United Slates for determining water and sediment in &.:de oil deliveries. Where used this method '1 w l l known. The most recent standard refcr-nce is Method D in ASTM Designation D - 63; API Standard 2542, published-in the :rWb o k of ASTM Standards, Part 18. METHOD A-LABORATORY CENTRIFUGE METHOD 3. ApparatUo 3.1 Cenlrifuge, capable of whirling two or more filled centrifuge tubes at a spccd which can be controlled to give a relative centrifugal force (rcf) of between 5 0 0 and 80C)at the tip of the tubes. The revolving head, trunnion rings, and trunnion cups, including the cushion, shall be soundly constructed to withstand the maximum centrifugal force capable of being delivered by the power source. The trunnion cups and cushions shall firmly support the tubes when the centrifuge is in motion. The centrifuge shall be enclosed by a metal shield or case strong enough to eliminate danger if any breakage occurs. Calculate the speed of the rotating head as follows: rpm = 265 I--Thc values stated in U.S. customary dfwa are to be regarded as the standard. L Sample 2.1 'nesample shall be thoroughly repre- *niaiive of the material in question and the ;'man used for the test shall be thoroughly 'cpmcntative of the' sample itself. This re' l ~vigior~ous agitation of the sample imme:ii~telyheforc transferring the sample to the l0he. Cold samples should be warmed to facil4 a k mixing. The difficulties in obtaining repWNativr samples for this determination are EnWally great; hence, the importance of umphng cannot be too strongly emphasized. where: rcf = relative centrifugal force, and d = diameter of swing, in., measured be- tween tips of opposite tubes when in rotating position. 3.2 Cenrruuge Tubes, cone-shaped, conforming to dimensions given in Fig. I and made of thoroughly annealed glass. The graduations. numbered as shown in Fig. 1 shall be clear and distinct, and the mouth constricted in shape for closure with a cork. Scale error tolerances and smallest graduations between 'Thew me!hds arc under the juridiction of A S T Y Committee D-2on Petroleum Products and Lubnuntr and thc ,\PI Central Cdmmictcc on Petroleum Measurement. -Current edition elkclive Scpt. 13, ,1968. Onpinilly ir- sued 1961. Replacer 0 96 63. 21 various calibration marks are given in 'Table 2. and apply to calibrations made with air- frie water at 20 c rcading the bottom of a shaded mcniscus. 3.3 Barh for Centrifuge Tubes-The bath shall be either a solid metal block or a liquid bath of sufficient depth for immersing the centrifuge tube in vertical position to the 100mi mark. Means shall be provided for main- taining ~eniperaturesat 120 & 2 F (49 * I C) and 140 2 F (60 f 1 C). 4. Sdveat 4 4.1 Toluene (Note 2) conforming to ASTM Specifications D 362, for Industrial Grade To1ucnr.l or benzene conforming to ASTM Specifications D 836, for Industrial Grade Runzene,' may be used as the solvent. A commercial demulsifie? may be added to the solvent but should not contribute to the water and sediment. The t y w and concentration is not limited, provided that the demulsifier itself does not contribute to the water and sedimt'nt. Commercial dentulsifiers at a concentration of 7 ml per loo0 ml of solvent have been successfully used (Note 3). NOTE2-Tolucne is the preferred solvan! beciluse of its lower toxicity. Nore 3-11 is rccognired that soiiic crudes may require (I) other solvents or ( 2 ) solvent-dcmulsifier combinations. Such solvents and dcmulsifiers as agrced upon between the purchaser and the scller may be u d after careful cxperimcntiltion to determine suitability and desirability. 4.2 The solvent shall bc saturated with water at ambient temperature but shall bc free of suspended water. Saturation may be accomplished by the addition of 2 ml of water per loo0 ml of solvent. A mechanical stirring device is recommended, but if none is available. shaking will aid in saturation. Adequate rettling time should be provided to ensure that the solvent is free of suspended watcr before UbC. mixed. Immerse the tubes to the 1W-tiil mark Tor IO min in the bath (see 3.3) maintained at 120 * 2 F (49 * I C). 5.1.1 I f wax contributes to the volume of water and sediment observed. preheat the oilsolvent mixture to 140 F (60 C) before each whirling; the final temperature of the mixture shall not drop below I I5 F (46 C). 5.2 Invert the tubes to assure that the oil and the solvent are uniformly mixed. I f necessary. shake cautiously. (Caution-The vapor pressure at 140 F is approximately double that at 100 F.) Place the tubes in trunnion cups on opposite sides of the centrifuge to establish a balanced condition. and whirl 10 min at a rate, calculated from the equation given in 3.1, sullicient 'LO produce a relative centrifugal force ( r c f ) of between 5 0 0 and 800 at the tip of the whirling tuber. (For the rela. tionship between diameter of swing, rcf, and rpm. see Table 1.) Read and record the conibined volume of water and sediment at the bottom of each tube to the nearest 0.05 ml from 0.1 to I-ml graduation and to the nearest 0.1 above I-ml graduation. Below 0.1 nil, estimate to the nearest 0.025 ml. Return the tubes without agitation to the cmtrifugr: and whirl for 10 min at the same rate. Repcat this operation until the combined volume of water arid sediment remains constant for two consecutive readings. In genernl, not more than two whirlings are required. NOTE 4-With ccnain types of oil it is dilficuil to obtain a clean break between the oil laycr and the separated water. In such cases one or more of the following remedies niay be effective: (I) raise the tempcriiiure to 140 F and guurd against 31lowing the temperature to drop below 115 F at the end of the run: ( 2 ) shake the mixture bciwcen whirl. ings in the centrirugc jus1 suflicienlly I O dispcrse the emulsion: (3) u x a different. or increased aniounl of dcmulsiher: houevcr, it rhould not contribute tC. the water and scdiincnt. A h a saiisbctory procc dure lor P particular type of oil has been workcc out. it will ordinarily be found suitablr fur all Sain pies of the s m c type. 5. I'rocrdure 5.1 Fill each of two centrifuge tubes (see 3.7) IO the 50-1111inark with solvent; then pour imniediatcly the well-shaken sample directly from the sample containsr into the centrifuge tubes until the total volume in each tube is IW ml. Stopper the rubes tightly and shake rigoroubly until the contents iirc thoroughly 5.3 Record the final volume of water an: sediment in each tube and report the sum c these two readings as the percentage of watc and sediment. 22 b. Report 6.1 The report shall include the following: 6.1.1 The percentage of water and scdiment. (Results lower than 0.05 percent reported either as zero or 0.05. whichever is closer.) . 6.1.2 The name of and amount of demulsifier used. 6.1.3 The solvent used if different from those in Section 4. 6.1.4 The bath temperature. clear and distinct. and the mouth constricted in shape for closure with $cork. Scale error and tolerances and smallest graduations be- tween various calibration marks are given in Table 4 and apply to calibrations made with air-free water at 20 C reading the bottom of a shaded meniscus. (This tube has generally been superseded by tubes shown in Figs. I and 4, however, its usc warrants inclusion in the method.) 8.5 Permissible Exception-When mutually agreeable, centrifuge tubes graduated in 200 7. Recisioa 7.1 The following criteria should be used for judging the acceptability of results (95 percnt probability): 7.1. I Repeatobiliry- Duplicate results by parts; direct reading in percent water and scdiment, may be used and may be 6-in. coneshaped or pear-shaped. The use of these tubes is limited to testing with equal parts of solvent and oil. the same operator should be considered suspect if they differ by more than the values shown on the "repeatability" curve in Fig. 3. 7.1.2 Reproducibility- The results submitted by each of two laboratories should be considered suspect if they differ by more than the values shown on the "reproducibility" curve in Fig. 3. METHOD B-FIELDCENTRIFUGE METHOD a~ ~ ~ ~ ~ t c r ~ 9. Sdrent 9.I The following solvents and demulsifiers have been reported as satisfactory for field testing. Solvents Dcmulsifien Stoddad Solvent Toluene Xylene Kerosine White gasoline Commercial crude oil demulsifien Phenol Nitrogen bans Naphihenic acids 9.1.1 Toluene and xylene shall be saturated with water at ambient or room temperature 8.1 Centrifuge for Field Use,meeting the requirements prescribed in 3.1. 3.2 Centrifuge Tube, 8-in. (203-mm)c,oneshaped as described in 3.2 and shown in Fig. I. 8.3 Cenrrifuge Tube, 6-in. (152-mm)c.oneshaped conforming to dimensions given in Fig. 4 and made of thoroughly annealed glass. The graduations, numbered as shown in Fig. 4. shall be clear and distinct, and the mouth constricted in shape for closure with a cork. &IC error tolerances and smallest gradualions between various calibration marks are given in Table 3. and apply to calibrations made with air-free water at 20 C, reading the h t o m of a shaded meniscus. While the use J f the 8-in. tube is preferable. the 6411. tube is but shall be free of suspended water. Solvents are toxic and care should be exercised in their use. Gasoline containing tetraethyl lead or deicer should never be used. When Stoddad solvent, kerosine. and white gasoline are used they must have similar solvent characteristics with respect to the crude oil being tested. 9.1.2 The usc of a demulsifier (resolving agent) with solvents shall be permitted subject to the mutual consent of dl1 parties concerned when tests demonstrate that correct results cannot otherwise be determined. The typc and concentration is not limited, provided that the demulsifier itself does not contribute to the water and sediment. Commercial demulsifiers.l at a ooncentrntion of 7 m1/1000 mi of solvent have been successfully used (Note 3). inc!ded because of the extensive use of centfifW3Uof limited diameter. 8.4 Centrifuge Tube. Pear-Sahped, conforming to dimensions given in Fig. 5 and ma& of thoroughly annealed glass. The grada t h ~ n,umbered as shown in Fig. 5 shall be 10. Procedure 10.1 Fill the ccntrifuge tube to the 50-1111 mark with solvent; then pour the well-shaken sample directly from the container into the tube until the total volume is I 0 0 mi. Stopper -_ G'., -. 23 the tube and shake until the contents are thor- type of oil has b a n worked out, it will ordi- h oughly mixed. Immerse the tube in a bath or narily be found suitable for aU samples of the -I dry heating device and heat the contents of Same type. the tube to 120 F. Where field conditions do not permit the use of sensitive temperature control devices, pocket-type thermometers 11. CalcJ.tion :9i 1 1 . 1 Multiply the reading obtained in ac- -9 may be used. In such cases every eflort should cordance with the procedure described in 10.1, be made to ensure a reasonably consistent bath temperature for the same oil at each time of testing. 10.2, and 10.3 by two and record the results as the percentage of water and sediment. For example, if a reading is 0.025 ml. record the 10.1.1 If wax contributes to the volume of percentage of water and sediment as 0.05. If a water and sediment observed, preheat the oil- reading is 0.15 ml, record the percentage of solvent mixture to 140 F before each whirling: water and sediment as 0.30. If the results are the final temperature of the mixutre shall not lower than 0.05 percent, record the percentage drop below 115 F. A heated centrifuge may of water and sediment as described in Section be required to maintain a final temperature of 12. When the ratio of solvent to oil is different 115 F. than 50 percent, the reading obtained in 10.3 10.2 Invert the tube to assure that the oil must be multiplied by the proper ratio factor and the solvent are uniformty mixed. I f in order to obtain the correct percentage of shaking is necessary, proceed cautiously be- water and sediment. cause the vapor pressure at 140 F is approximaiely double that at 100 F. Place tubes in 12. Record trunnion cups on opposite sides of the centri- 12.1 The record shall include the following: fuge to establish a balanced condition, and 12.1.1 The percentage of water and sedi- whirl for 3 to IO min depending upon the ment. (Results lower than 0.05 percent re- character of the sample. at a rate calculated ported either as zero or 0.05. whichever is from the equation given in 3.1. suficient to closer.) produce a relative centrifugal force (rcf) of 12.1.2 The solvent used. betwecn 500 and 800 at the tip of the whirling 12.1.3 The type of and amount of demulsi- tubes. (For the relationship between diameter fier if used. of swing. rcf, and rpm. see Table 2.) 12.1.4 The bath temperature. 10.3 Read and record the combined volume of water and sediment at the bottom of the 13. Precision tube to the nearest 0.05 ml from 0.1 to I-ml 13.1 For methods using the 8-in. conc graduation and to the nearest 0.1 above I-ml shaped tube, as in Section 8, or the 6-i.n. con( graduation. Below 0.1 mi, estimate to the shaped tube, the following criteria should t nearest 0.025 ml. If experience with the oil is used for judging the acceptability of m u ! limited, it is advisable to return the tube to (95 percent probability): the centrifuge without agitation and repeat 13.1.1 Repeorobiliry-Duplicatc results ' the operation. the same operator should be considercd si 10.3.1 With certain types of oil it is diffi- pect if they differ by more than the vali cult to obtain a clean break between the oil shown on the "repeatability" curve (Fig. 6). layer and the separated water. In such cases 13.1.2 Reproducibilily-The results s i one or more of the following remedies may be mitted by each of two separate parties sho effective: ( I ) raise the temperature to 140 F; be considered suspect if they differ by m ( 2 ) shake &he mixture between whirlings in than the values shown on the "reproduci the centrifuge just sufficiently to disperse the ity" curve (Fig. 6). emulsion: (3) use a different. or increased 13.2 For the method using pear-sha amount of demulsifier: however. it should not tubc the following criteria should be used contribute to the water and sediment: ( 4 ) use judging the acceptability of results (95 per( a different. or increased amount of solvent. probability). After a satisfactory procedure for a particular 13.2.1 Repeorabilirp-Duplicate -r_csuli: 24 the same operator should be considered sus- Pct if they differ by more than the following: Water and Sediment (Volume Percent) Repeatability 0 to 0.5 0.5 to 1.5 0.I 0.2 13.2.2 Reproducibility figures are not available. each tube to the nearest 0.1 percent. 16.2 Replace the tubes in the centrifuge and revolve again for from 3 to 10 min. Again record the combined water and sediment. If there is a difference of more than 0.2 percent between the first and second -readings. continue centrifuging until two consecutive readings check within 0.2 percent. METHOD C-FIELDCENTRIFU,GMEETHOD- 17. Calculation 1 2 . 5 0 - ~T~U B E - C R U DOEILS 17.1 The sum of the final readings on the NOTE 5-This method is u x d for crude oil in some areas of the United States and is therefore included in the standard. two 12.50-ml centrifuge tubes represents the volume percentage of water and sediment in the crude oil tested. 14. Apparatus 14.1 Centrifuge /or Field Use. either handor electrically powered, meeting the requirements prescribed in 3.1 (see Table 2). 14.2 Centrifuge Tube, A P I . 12.5o-m1 Capocity-The capacity of this tube shall be 12.50 ml in the calibrated portion, with capacity, dimensions. graduations, tolerances. and 18. Report 18.1 The report shall include: 18.1.1 The percentage of water and sediment. 18.1.2 The solvent used, and 18.1.3 The type and amount o f demulsifier if used. markings as shown i n Fig. 7 and Tables 5. 6. and 7. 14.2.1 Limir of Error (plus or minus tolerance) is based on the total calibrated volume 19. Precision 19.1 The precision of this method has not been established. of tube as shown in Table 7. Molded tubes are preferred. Blown tubes that comply with METHOD D-BASEMETHOD the stipulations on uniform wall thickness are 20. Procedure satisfactory. All centrifuge tubes shall be retempered to remove manufacturing strains. The lower end of the centrifuge tube must be clear and perfectly rounded inside, with the same thickness of glass as in the main body of the tube. 20.1 The sum of the results obtained in accordance with ASTM Method D 95 - API 2560. Test for Water in Petroleum Products and Other Bituminous Materials.' and ASTM Method D 473 - API 2561, Test for Sediment in Crude and Fuel Oils by Extraction,' shall 15. SaIvent 15.1 Solvents and demulsifiers to be used in this method are the same as given in Section 9 for Method B. be assumed to be the correct value for water and sediment. These methods shall be considered as the "base method," and shall be used when agreement cannot be reached between the purchaser and the seller when using any of 16. Procedure 16.1 Fill two tubes (Section 14) to the 50 percent mark, with tbe solvent, with o r without Ztemulsifier and then to the 100 percent mark with the sample of oil to be tested. Stopper the tubes and shake until the contents art thoroughly mixed, place them in the centrifuge and revolve at the rate of 1 5 0 rpm for 3 to 10 min. depending upon the character of the sample. Remove the tubes and record the the other methods described. The base method shall be considered the standard method of test for crude oils and fuel oils having characteristics not suitable for test by the centrifuge method. The base method shall be used as J criterion to compare the effectiveness of solvents, with o r without demulsifien. used in Methods A. B. and C. 20.2 For crude oils containing sediment in accordance with Method D 473 - API 2561 combined volume of water and sediment in -.'Annual Book of ASTM Slundards, Pan 1s. S!b - '40 96 2542 in excess of 0.02 weight percent, the results shall be converted to a volume basis because water and sediment values are commonly reported in volume percent. As the major portion of the sediment would probably be sand (silicon dioxide. which has a specific gravity of 2.32) and a small amount of other naturaloccurring materials (with a specific gravity lower than that of sand) an arbitrary specific gravity of 2.0 shail be used for the resulting sediment. Then, to obtain volume percent sediment. the weight percent sediment obtained in accordance with Method D 473 - API 2561 shall be divided by two. TABLE I Rotation .Speeds Applicable for Cmtnfuges of Variola Diameters of swing 21. Calculation .a%21.1 Calculate the percentage of water in accordance with Method D 95 - API 2360. :2$Convert the weight percentage sediment ob- : tained in accordance with Method D 473 L ? API 2561 to volume percentage h described. Calculate the volume percentage of water and , sediment by adding the two results. 22. Precision -*rr .,.f: -* 5 22.1 Worer-SCe Section 8 of Method D i: 95 - A P I 2560. i: 22.2 Sediment-See Section 7 of Method D f 473 - A P I 2561. ?9 i TABLE 3 Centrifuge Tube Calibration Tdtin. (1SZnm)Tube -r for 6- , Diamctcr of Swing. in. (mm)" Rpm at 500 rcr Rpm at 800 rcf 12 (3cM\ 13 (330) 14 (3551 I5 (361) 16 (406) 17 (4311 18 (457) 19 (482) 20 (508) 21 (533) 22 (558) 23 (564) 24 (ho9) 1710 I650 I590 1510 1480 1440 1400 13ho 1330 1300 1270 I240 1210 2160 2080 2Mw) I930 1870 1820 1770 1720 1680 1640 1600 I560 1530 'Mcdsurcd in inchcs (or millimeters) k l w e c n ilps Of opposite tubes when in rotating position. Range. ml 0 10 0.1 Above 0.1 to 0.3 Abovc 0.3 to 0.5 Abovc 0.5 l o I .O Above 1.0 IO 1.5 Above 1.5 to 2 Above 2 to 3 Above 3 to 5 Above 5 to IO Abovc IO to 25 at 50.75. and 100 Subdivision. rnl 0.05 0.05 0.05 0.10 0. IO 0.10 0.20 0.50 I 5 ... Volumc Tolcrancc. ml tO.02 *0.03 tO.05 r0.075 ao.I O tO.20 t0.30 t0.50 t0.75 tl.0 t1.5 ~: TABLE 4 Pear-Shaped CeRlrifUpe Tube Calibration Tolcn~ccs T 4 B L E 2 Ceocrifuge Tube Calibnlion Tolerance for 8in. I 203mm Tube Range. ml ~~ otoo.1 Abovc 0.1 to 0.3 Above 0.3 10 0 5 Above 0.5 to I 0 Abuvc I .O I O 2.0 Ahovc 2.0 to 3.0 Abovc 3.0IO 5.0 Abovc 5.0 10 IO Abovc IO to 2 5 Above 2 5 to I00 Ssuiobnd. 'mv'l- 0.05 0.0' 0.05 0. IO 0. IO 0.20 0.5 1 .o 5.0 25 Vol unie Tolcrancc. ml tO.02 *0.03 4J.05 rO.05 t0 IIJ rO.10 to.20 t o so *I w t 1.00 Range. ml 0 10 1.5 Over 1.5 I O 3.0 Over 3.0 to 5.0 0 w r 5.0 IO 10.0 Over I O to 25 over 25 tu loo Smallcsl Scale Divisiun. ml 0.I 0.5 0.5 I 5 2' Maximum Scillc Error. ~ i l 0.03 0.20 O.?O 0.50 I .o :. O 26 TABLE 5 Capacity of l23&nd Centrifuge Tube PIenrdciecnattaegde Milliliters I 0.125 2 0.250 3 0.375 5 0.625 IO 1.250 I5 1.875 20 2.500 25 3.125 30 3.750 35 4.375 40 5.000 45 5.625 50 6.150 100 12.500 I -1-1 I I--IO 195. TABLE 6 Specification. for I2Jg.d Ceatrifugc T u k Gmdxaolronr Graduations shall be marked as follows: 0 to 3 percent 0.2 of I percent 3 to IO percent 0.5 o f I percent 10 to SO percent I .O percent 50 IO100 percent blank *Spuurfira:ioru Length. over-all: 118 2 mm *b 8 t h . 0 to 50 percent: 66 t 4 mm Length. SO to 100 percent: 35 3 rnm Len& t a p e d pan: 56 to 62 mm Length. untapered part: 58 to 60 mm Rim thickness: 2 to 3 mm. included in over-all measurement Diameter. untapcmd: 17 * 0.25 mm *Diameter. bottom. at the 0.3 percent marking: 5 I mm Normal thickness: perfect xmtcircle bottom. TABLE 7 T o l c r a ~ mfor 12.U)-nl Centrifprr Tube Range percent 010 I I to 2 210 3 310 5 5 to IO loto 25 25 to 50 5010 100 Tolerance. percent aO.l a0.15 *0.2 *0.2 *0.4 *OS *l.O *i,o Volumetric Capacity. ml *0.0125 t0.0188 aO.OtU) *0.0250 *0.0.(00 *0.0625 t0.1250 +O. I250 NOTE-For volumctnc tolerances. see Table 2. FIG. I Eight-lncb (203-mm) Ceatrifugc Tube. II/* ......... -..................... -...................... --...-...................................... I .......... -................... -................. -................ -................ 'II ...... -............... -............ -............. -............ ....... - I............ ........ L-........ ...... .~. . . . . .. , ..,.%I... .....,..-...._..,. 27 . Precision.95 percent Confidence Limit FIG. 3 Prrcision CUT)- for Centrifuge Tube Metbod. .. cc FIG. 7 CentrifugeTube, 12.M.d Capacity. By publication ofrhic standard no position ir taken with respect to the validity of any patent rights in connection rherevith, and !he AMrican So&;y for Testing a d Materia& does not undertake to insure anyone utiking the standard agmnrr liability for infringement of any Letters Patent nor assume ony such liability. 29