D-525: Standard Test Method for Ramsbottom Carbon Residue of Petroleum Products1

Designation: D 524 – 03

Designation: 14/94

Standard Test Method for

Ramsbottom Carbon Residue of Petroleum Products1

An American National Standard

British Standard 4451

This standard is issued under the fixed designation D 524; 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 last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

This standard has been approved for use by agencies of the Department of Defense.

1. Scope*

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 it is intended to provide some indication of relative coke-forming propensity. This test method is generally applicable to relatively nonvolatile petroleum products which partially decompose on distillation at atmospheric pressure. This test method also covers the determination of carbon residue on 10% (V/V) distillation residues (see Section 10). Petroleum products containing ash-forming constituents as determined by Test Method D 482, will have an erroneously high carbon residue, depending upon the amount of ash formed (Notes 2 and 3).

NOTE 1—The term carbon residue is used throughout this test method to designate the carbonaceous residue formed during evaporation and pyrolysis of a petroleum product. 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 D 189, or Test Method D 4530. Approximate correlations have been derived (see Fig. X2.1) but need not apply to all materials which can be tested because the carbon residue test is applicable to a wide variety of petroleum products. The Ramsbottom Carbon Residue test method is limited to those samples that are mobile below 90°C.

NOTE 3—In diesel fuel, the presence of alkyl nitrates such as amyl nitrate, hexyl nitrate, or octyl nitrate, causes a higher carbon 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 D 4046.

NOTE 4—The test procedure in Section 10 is being modified to allow the use of a 100–mL volume automated distillation apparatus. No precision data is available for the procedure at this time, but a round robin is being planned to develop precision data. The 250–mL volume bulb

distillation method described in Section 10 for determining carbon residue on a 10 % distillation residue is considered the referee test.

1.2 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 appro- priate safety and health practices and determine the applica- bility of regulatory limitations prior to use.

2. Referenced Documents

2.1 ASTM Standards:

D 86 Test Method for Distillation of Petroleum Products at

Atmospheric Pressure2

D 189 Test Method for Conradson Carbon Residue of

Petroleum Products2

D 482 Test Method for Ash from Petroleum Products2

D 4046 Test Method for Alkyl Nitrate in Diesel Fuels by

Spectrophotometry3

D 4057 Practice for Manual Sampling of Petroleum and

Petroleum Products3

D 4175 Terminology Relating to Petroleum, Petroleum

Products, and Lubricants3

D 4177 Practice for Automatic Sampling of Petroleum and

Petroleum Products3

D 4530 Test Method for Determination of Carbon Residue

(Micro Method)3

E 1 Specification for ASTM Thermometers4

E 133 Specification for Distillation Equipment5

2.2 IP Standards:

Appendix AP-A Specifications—IP Thermometers6

3. Terminology

3.1 Definitions:

3.1.1 carbon residue, n—the residue formed by evaporation and thermal degradation of a carbon containing material.

1 This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.06 on Analysis of Lubricants.

Current edition approved Sept. 10, 2003. Published September 2003. Originally approved in 1939. Last previous edition approved in 2000 as D 524–00e1.

In the IP, this test method is under the jurisdiction of the Standardization

Committee.

2 Annual Book of ASTM Standards, Vol 05.01.

3 Annual Book of ASTM Standards, Vol 05.02.

4 Annual Book of ASTM Standards, Vol 14.03.

5 Annual Book of ASTM Standards, Vol 14.02.

6 IP Standard Methods for Analysis and Testing of Petroleum and Related Products, 1998. Available from Institute of Petroleum (IP), 61 New Cavendish St., London, WIG 7AR, U.K.

*A Summary of Changes section appears at the end of this standard.

Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.

D 4175

3.1.1.1 Discussion—The residue is not composed entirely of carbon but is a coke that can be further changed by carbon pyrolysis. The term carbon residue is retained in deference to its wide common usage.

4. Summary of Test Method

4.1 The sample, after being weighed into a special glass bulb having a capillary opening, is placed in a metal furnace maintained at approximately 550°C. The sample is thus quickly heated to the point at which all volatile matter is evaporated out of the bulb with or without decomposition while the heavier residue remaining in the bulb undergoes cracking and coking reactions. In the latter portion of the heating period, the coke or carbon residue is subject to further slow decomposition or slight oxidation due to the possibility of breathing air into the bulb. After a specified heating period, the bulb is removed from the bath, cooled in a desiccator, and again weighed. The residue remaining is calculated as a percentage of the original sample, and reported as Ramsbottom carbon residue.

4.2 Provision is made for determining the proper operating characteristics of the furnace with a control bulb containing a thermocouple, which must give a specified time-temperature relationship.

5. Significance and Use

5.1 The carbon residue value of burner fuel serves as a rough approximation of the tendency of the fuel to form deposits in vaporizing pot-type and sleeve-type burners. Simi- larly, provided alkyl nitrates are absent (or if present, provided the test is performed on the base fuel without additive) the carbon residue of diesel fuel correlates approximately with combustion chamber deposits.

5.2 The carbon residue value of motor oil, while at one time regarded as indicative of the amount of carbonaceous deposits a motor oil would form in the combustion chamber of an engine, is now considered to be of doubtful significance due to the presence of additives in many oils. For example, an ash-forming detergent additive can increase the carbon residue value of an oil yet will generally reduce its tendency to form deposits.

5.3 The carbon residue value of gas oil is useful as a guide in the manufacture of gas from gas oil, while carbon residue values of crude oil residuum, cylinder and bright stocks, are useful in the manufacture of lubricants.

6. Apparatus

6.1 Glass Coking Bulb, of heat-resistant glass conforming to the dimensions and tolerances shown in Fig. 1. Prior to use, check the diameter of the capillary to see that the opening is greater than 1.5 and not more than 2.0 mm. Pass a 1.5-mm diameter drill rod through the capillary and into the bulb; attempt to pass a 2.0-mm diameter drill rod through the capillary. Reject bulbs that do not permit the insertion of the smaller rod and those whose capillaries are larger than the larger rod.

6.2 Control Bulb, stainless steel, containing a thermocouple and conforming to the dimensions and tolerances shown in Fig.

NOTE—All dimensions are in millimetres.

FIG. 1 Glass Coking Bulb

2, for use in determining compliance of furnace characteristics with the performance requirements (Section 7). The control bulb shall be provided with a dull finish, as specified in Fig. 2, and must not be polished thereafter. A polished bulb has different heating characteristics from one with a dull finish. A suitable thermocouple pyrometer for observing true tempera- ture within 61°C is also required.

6.3 Sample Charging Syringe, 5 or 10-mL glass hypodermic (Note 5), fitted with a No. 17 needle (1.5 mm in outside diameter) or No. 0 serum needle (1.45 to 1.47 mm in outside diameter) for transfer of the sample to the glass coking bulb.

NOTE 5—A syringe having a needle that fits on the ground-glass tip of the syringe is not recommended, as it may be blown off when pressure is applied to the syringe plunger. The Luer-Lok type syringes are more satisfactory, as the needle locks on the bottom of the syringe barrel, and cannot be

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