An American National Standard
Standard Test Method for
Salts in Crude Oil (Electrometric Method)1
This standard is issued under the ﬁxed designation D 3230; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope* 1.1 This test method covers the determination of the approximate chloride (salts) concentration in crude oil. The range of concentration covered is 0 to 500 mg/kg or 0 to 150 lb/1000 bbl as chloride concentration/volume of crude oil. 1.2 This test method measures conductivity in the crudeoil due to the presence of common chlorides, such as sodium, calcium, and magnesium. Other conductive materials may also be present in the crude oil. 1.3 The values stated in SI units are to be regarded as standard. Acceptable concentration units are g/m3 or PTB (lb/1000 bbl). 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For speciﬁc warning statements, see 7.3, 7.4, and 7.11. 2. Referenced Documents 2.1 ASTM Standards: 2 D 91 Test Method for Precipitation Number of Lubricating Oils D 381 Test Method for Gum Content in Fuels by Jet Evaporation D 1193Speciﬁcation for Reagent Water D 4928 Test Methods for Water in Crude Oils by Coulometric Karl Fischer Titration D 5002 Test Method for Density and Relative Density of Crude Oils by Digital Density Analyzer
3. Terminology 3.1 Deﬁnitions of Terms Speciﬁc to This Standard: 3.1.1 PTB—lb/1000 bbl. 3.1.2 salts in crude oil—commonly, chlorides of sodium, calcium, and magnesium dissolved in crude oil.Other inorganic chlorides may also be present. 4. Summary of Test Method 4.1 This test method measures the conductivity of a solution of crude oil in a mixed alcohol solvent when subjected to an electrical stress. This test method measures conductivity due to the presence of inorganic chlorides, and other conductive material, in the crude oil. A homogenized test specimen is dissolved in a mixedalcohol solvent and placed in a test cell consisting of a beaker and a set of electrodes. A voltage is impressed on the electrodes, and the resulting current ﬂow is measured. The chloride (salt) content is obtained by reference to a calibration curve of current versus chloride concentration of known mixtures. Calibration curves are based on standards prepared to approximate the type and concentrationof chlorides in the crude oils being tested. 5. Signiﬁcance and Use 5.1 This test method is used to determine the approximate chloride content of crude oils, a knowledge of which is important in deciding whether or not the crude oil needs desalting. The efficiency of the process desalter can also be evaluated. 5.2 Excessive chloride left in the crude oil frequently results in higher corrosionrates in reﬁning units and also has detrimental effects on catalysts used in these units. 5.3 This test method provides a rapid and convenient means of determining the approximate content of chlorides in crude oil and is useful to crude oil processors. 6. Apparatus 6.1 The apparatus (see Annex A1) shall consist of a control unit capable of producing and displaying several voltage levels for applyingstress to a set of electrodes suspended in a test beaker containing a test solution. The apparatus shall be
1 This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.03 on Elemental Analysis. Current edition approved Nov. 1, 2005. Published November 2005. Originally approved in 1973. Last...