1、K 665.7: 620.1 : 543.842 DEUTSCHE NORM March 1994 I I Determination of carbon-type composition of mineral oils DIN 51 378 Prfung von Minerallen; Bestimmung der Kohlenstoffverteilung Supersedes April 1976 edition. See Explanatory notes for connection with ASTM D 21 40-91 published by the American Soc
2、iety for Testing and Materials (ASTM). In keeping with current practice in standards published by the International Organization for Standardization (ISO), a comma has been used throughout as the decimal marker. 1 Field of application This standard covers unused mineral oils with an average molecula
3、r mass of more than 200, which do not contain additives foreign to mineral oils and have a viscosity-grav- ity constant of less than 0,98. The test method may also be applied to inhibited insulating oils. 2 Scope The method described in this standard serves to determine the carbon-type composition o
4、f mineral oils, expressed in terms of fractions, X, of carbon atoms that are combined in aromatic rings (A), in naphthenic rings (N) and in paraffinic chains (P). These fractions (X(A), X(N) and X(P) characterize the sta- tistical composition of the mineral oil, but do not provide any information on
5、 its chemical structure. 3 Concept The fraction of a constituent X, X(X), is the ratio of the number of atoms of the constituent X, N(X), and the sum of the number of atoms of all such constituents, 2 N(X), of an unused mineral oil. 4 Principle The kinematic viscosity, the density, the refractive in
6、dex and the sulfur content of the sample are determined in order to calculate the viscosity-gravity constant and the refrac- tivity intercept. The carbon-type composition, in terms of X(A), X(N) and X(P) percentage fractions, is then read from the nomogram or calculated by computer. Subject to agree
7、ment, X(A), X(N) and X(P) are reported either with (calculation method K) or without (calculation method U) sulfur correction. 5 Sampling Sampling shall be carried out as specified in DIN 51 750 Parts 1 and 2. 6 Procedure 6.1 Determination of density, kinematic visco- sity, refractive index and sulf
8、ur content 6.1.1 Density Determine the density at 15C as described in DIN 51 757. 6.1.2 Kinematic viscosity Determine the kinematic viscosity, in mm2/si), at 40 “C using the Ubbelohde viscometer as described in DIN 51 562 Part 1. 6.1.3 Refractive index Determine the refractive index at 20C as descri
9、bed in DIN 51 423 Part 1 or 2. NOTE: In the case of oils having a colour index of more than 6, a reduction in the precision of the meas- urement is to be expected, its effect on the carbon- type composition being generally negligible. 6.1.4 Sulfur content Determine the sulfur content, as a percentag
10、e by mass, as described in DIN51400 Part2, 3 or 6, or as described in DIN EN 41. 6.2 Calculation of viscosity-gravity constant and refractivity intercept Calculate the viscosity-gravity constant, VGC, and the re- fractivity intercept, ri, using equations (1) and (2). e - 0,0822 - 0,776 Lglg (1 OV -
11、4) 1,0763 - 0,72 Lglg (1 OV - 4) e - 0,0030 2 (1) 1 (2) VGC = I. =n- where e is the density at 15“C, in kg/l; Y is the kinematic viscosity at 40 OC, in mm2/s; n is the refractive index for the sodium D line at 20 “C. 1) 1 mm2/s = 1 cSt = 10-6mZ/s (mVs is the SI unit of the kine- matic viscosity). Co
12、ntinued on pages 2 to 4. uth Verlag GmbH, Berlin, has the exclusive right of sale for German Standards (DIN-Normen). DIN 51 378 Eng/. Price group 6 04.96 Sales No. O106 Page 2 DIN 51 378 Table 1: Example of calculations as described in subclauses 6.2 to 6.4 Epression of results Measured values: dens
13、ity at 15“C, e, in kg/i kinematic viscosity at 40C, Y, in mmVs refractive index at 20C, ?I sulfur content, w (S), as a percentage by mass Calculated values: VDC ri Taken from nomogram: Calculation method U: X (A) % X (N) % x (P) % Calculation method K: X, (A) % Xi (N) % xi (P) % Oil No. 1 0,8597 7,6
14、2 1,4738 0,Ol 0,831 1,0455 7 34 59 7 34 59 Oil No. 2 0,8990 500,O 1,4935 0,90 0,81 O 1,0455 4 29 67 4 26 71 6.3 Carbon-type composition Use the viscosity-gravity constant, VGC, and the refractivity intercept, T, calculated from equations (1) and (2), re- spectively, to read from the nomogram (cf. fi
15、gure 1) frac- tions X(N) and X(A) or to calculate the percentage fractions by computer2) (calculation method U). This method is not suitable for mineral oils having VGC and ri lines intersect- ing outside the nomogram. Take the sulfur content of the sample analysed into account as described in subcl
16、ause 6.4 and correct fractions X(N) and X(A) accordingly (calculation method K). 6.4 Sulfur correction of fractions read from the nomogram Correct fractions X(N) and X(A) read from the nomogram for the sulfur content using equations (3) and (4). Xi(A) = X(A) - 1,158 * w(S) Xi(N) = X(N) - 3,472 * w(S
17、) Xi(P) = 100 - (X,(A) + X,(N) (3) (4) Calculate fraction X,(P) from fractions X,(A) and X,(N), using equation (5). (5) is the fraction of the carbon atoms combined in aromatic rings, corrected for the sulfur content, as a percentage by mass; is the fraction of the carbon atoms combined in naphtheni
18、c rings, corrected for the sulfur content, as a percentage by mass; is the fraction of the carbon atoms bound in paraffinic chains, corrected for the sulfur content, as a percentage by mass: is the sulfur content, as a percentage by mass. 7 Expression of result The test report shall refer to this st
19、andard and report the fractions X general Sampling of liquid petroleum products Determination of density of petroleum products Testing of petroleum products; precision; terminology and its application to petroleum standards speci- fying requirements Determination of sulfur content of petroleum produ
20、cts by the Wickbold combustion method Test method for carbon-type composition of insulating oils of petroleum origin*) Other relevant document 111 Kurtz, S.S. Jr, King, R.W, Stout, W.J, Partikian, D.G and Skrabek, E.A., Relationship between carbon-type composition, viscosity-gravity constant and ref
21、ractivity intercept of viscous fractions of petroleum. Analytical chemistry, 1956: 28 (1 2), 1928-1 936 Previous edition DIN 51 378:04.76. Amendments The following amendments have been made to the April 1976 edition. a) The fractions of carbon atoms may now also be calculated by computer. b) The tem
22、perature at which the density is to be determined has been reduced from 20C to 15C. c) The temperature at which the kinematic viscosity is determined has been changed from 37,8“C to 40C. d) The result may optionally be reported with or without sulfur correction. A calculated example has been include
23、d. e) The text has been editorially revised to take into account the specifications in standards of the DIN 820 and DIN 1310 series, and references to other standards have been updated. Explanatory notes This standard has been prepared by Technical Committee Prfung von Schmierlen, sonstigen Oien und
24、 Paraffinen of the Fachausschu Minerall- und Brennstoffnormung of the Nonnenausschu Materialprfung (Materials Testing Standards Committee). The method specified in this standard is equivalent to that described in ASTM D 2140-91, but differs in some minor respects from the latter (wider scope, correction for the sulfur content optional, equations (1) and (2) based on l). International Patent Classification C 10 M 101/02 G O1 N O33126 c 1 o L 001/00 *) Obtainable from Beuth Verlag GmbH, Auslandsnormenverkauf, Burggrafenstrae 6, D-10787 Berlin.
