ASTM D524 method for Ramsbottom carbon residue of petroleum products
9. Procedure
9.1 Place a new glass coking bulb (Note 12) in the coking furnace at 550°C for about 20 min to decompose any foreign organic matter and to remove water. Place in a closed desiccator over a suitable desiccant, such as a desiccant containing CaCl2 or CaSO4, for 20 to 30 min, and then weigh to the nearest 0.1 mg.
NOTE 11 - Do not reuse a glass coking bulb, as unpredictable results are sometimes obtained in such cases. For routine testing, new bulbs can be used without pre-ignition provided they are visibly free from particles or other contamination. Such bulbs, at least, should be heated in an oven to 150°C, placed in a desiccator, and then weighed.
NOTE 12 - On making a test, it is important to adhere rigorously to the temperature conditions chosen for Section 7; for example, if the bath was at a temperature of 553 +/- 1°C when inserting the control bulb, then it is necessary to use similar temperature conditions in the coking test. When maintained in normal operation, the temperature of an electrically heated furnace with automatic controls will generally fluctuate within a specific temperature range. Therefore, when making a coking test, it is generally important that the test bulbs be inserted when the furnace is at the same temperature or at the same position in the temperature cycle as it was when the inspection test was started, unless it has been proven that the temperature variations are inappreciable.
9.2 Shake thoroughly the sample to be tested, first heating to 50° +/- 10°C for 0.5 h when necessary to reduce its viscosity. Immediately following the heating and shaking, strain the sample through a 100-mesh wire screen. By means of a hypodermic syringe or the device shown in Fig. 3 introduce into the coking bulb an amount of sample as indicated in Table 1. Make sure that no oil remains on the exterior surface or on the inside of the neck of the bulb. Reweigh the bulb and contents to the nearest milligram. If the sample foams or spatters, repeat the test using the next smaller sample size listed in Table 1. In reporting the results, include the size when such small samples are used. If difficulty is encountered in loading very viscous or asphaltic samples of any size into the glass coking bulb, the apparatus shown in Fig. X1.2 can be used.
9.3 Place the coking bulb in a standard performance well with the furnace at the checking temperature (Note 12), and allow to remain for 20 +/- 2 min. Remove the bulb with metal tongs, the tips of which have just been heated. Duplicate the furnace and bulb conditions used when standardizing that bulb well (Section 7 and Note 9). If there is appreciable loss of oil from frothing, discard the test and repeat the determination using a smaller sample (Note 13).
NOTE 13 - Frothing can be due to water which can be removed by heating gently in a vacuum and sweeping out the vapor with nitrogen prior to filling the bulb.
9.4 After removal, cool the bulb in a desiccator under the same conditions (including time for weighing) used before filling the bulb (9.2). When removing the bulb from the desiccator, examine it to make sure there are no foreign particles adhering to the bulb; if any are found, as black particles sometimes are on the capillary neck, brush them off with a piece of sized paper or camel's hair brush. Weigh to the nearest 0.1 mg. Discard the used glass coking bulb.
NOTE 14 - In studies of oil characteristics, useful information can often be gleaned from a simple visual examination of the coking bulb after the test. Thus, significance can be attached to noting, with the results, such findings as: coke more or less fills the bulb; liquid material is present, either as limpid residue or drops; the residue is not black and flaky, but is colored and pulverulent (presumably from presence of inorganic materials).
10. Procedure for Carbon Residue on 10 % (V/V) Distillation Residue 10.1 This procedure is applicable to middle distillate materials, such as ASTM No. 1 and No. 2 fuel oils.
10.2 A distillation analysis using either a 100 or 200-mL starting volume is required in order to collect a sufficient amount of the 10 % (V/V) residue needed in this analysis. For a 100-mL distillation, assemble the distillation apparatus described in either Test Method D86 or Specification E 133. Use a distillation flask with a 125-mL bulb volume, a flask support board with a 50-mm diameter opening, and a graduated cylinder with a 100-mL capacity. For a 200-mL distillation, assemble the distillation apparatus described in Specification E 133, using flask D (250-mL bulb volume), flask support board with 50-mm diameter opening, and graduated cylinder C (200-mL capacity). A thermometer is not required, but the use of the ASTM High Distillation Thermometer 8F or 8C, as prescribed in Specification E 1, or the IP High Distillation Thermometer 6C, as prescribed in Specifications - IP Thermometers, is recommended.
10.3 Depending upon which distillation flask is used, place either 100 or 200 mL of sample (as measured at ambient temperature) into the distillation flask that is held at a temperature between 13°C and ambient. Maintain the condenser bath temperature between 0 and 60°C to provide a sufficient temperature differential for sample condensation. Avoid any solidification of waxy material in the condenser tube. Place, without cleaning, the cylinder which was used to measure the sample under the condenser tube so that the tip of the condenser does not touch the wall of the cylinder. The receiver temperature shall be maintained at the same temperature (within +/- 3°C) as when the sample was taken at the start of the test in order to obtain an accurate volume measurement in the receiving flask.
10.4 Apply the heat to the flask at a uniform rate so regulated that the first drop of condensate exits from the condenser between 10 and 15 min (for 200-mL samples) or between 5 and 15 min (for 100-mL samples) after initial application of heat. If a receiving cylinder deflector is not being used, immediately move the receiving cylinder so that the tip of the condenser tube touches the inner wall of the cylinder after the first drop falls. Then regulate the heat so that the distillation proceeds at a uniform rate of 8 to 10 mL/min (for 200-mL samples) or 4 to 5 mL/min (for 100-mL samples). For 200-mL samples, continue the distillation until approximately 178 mL of distillate has been collected, and then discontinue heating and allow the condenser to drain until 180 mL (90 % (V/V) of the charge to the flask) has been collected in the cylinder. For 100-mL samples, continue the distillation until approximately 88 mL of distillate has been collected, and then discontinue heating and allow the condenser to drain until 90 mL (90 % V/V) of the charge to the flask) has been collected in the cylinder.
10.5 Catch final drainage, if any, by immediately replacing the cylinder with a suitable container, such as a small Erlenmeyer flask. Add to this container, while still warm, the distillation residue left in the distilling flask, and mix well. The contents of the container then represents a 10 % (V/V) distillation residue from the original product.
10.6 While the distillation residue is warm enough to flow freely, place 4.0 +/- 0.1 g of it into the previously weighed coking bulb. A hypodermic syringe provides a convenient means of performing this operation. After cooling, weigh the bulb and contents to the nearest 1 mg, and carry out the carbon residue test in accordance with the procedure described in Section 9.
10.7 Report the percentage of carbon residue as the Ramsbottom carbon residue on 10 % distillation residue.
