ASTM D189 : 24

Standard Test Method for Conradson Carbon Residue of Petroleum Products

Standard Details

1.1 This test method covers the determination of the amount of carbon residue (Note 1) left after evaporation and pyrolysis of an oil, and is intended to provide some indication of relative coke-forming propensities. This test method is generally applicable to relatively nonvolatile petroleum products which partially decompose on distillation at atmospheric pressure. Petroleum products containing ash-forming constituents as determined by Test Method D482 or IP Method 4 will have an erroneously high carbon residue, depending upon the amount of ash formed (Note 2 and Note 4).

Note 1: The term carbon residue is used throughout this test method to designate the carbonaceous residue formed after evaporation and pyrolysis of a petroleum product under the conditions specified in this test method. The residue is not composed entirely of carbon, but is a coke which can be further changed by pyrolysis. The term carbon residue is continued in this test method only in deference to its wide common usage.

Note 2: Values obtained by this test method are not numerically the same as those obtained by Test Method D524. Approximate correlations have been derived (see Fig. X1.1), but need not apply to all materials which can be tested because the carbon residue test is applied to a wide variety of petroleum products.

Note 3: The test results are equivalent to Test Method D4530, (see Fig. X1.2).

Note 4: In diesel fuel, the presence of alkyl nitrates such as amyl nitrate, hexyl nitrate, or octyl nitrate causes a higher residue value than observed in untreated fuel, which can lead to erroneous conclusions as to the coke forming propensity of the fuel. The presence of alkyl nitrate in the fuel can be detected by Test Method D4046.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 WARNING—Mercury has been designated by many regulatory agencies as a hazardous substance that can cause serious medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Use caution when handling mercury and mercury-containing products. See the applicable product Safety Data Sheet (SDS) for additional information. The potential exists that selling mercury or mercury-containing products, or both, is prohibited by local or national law. Users must determine legality of sales in their location.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International StandardDetails, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.