10. Procedure for Carbon Residue on 10 % Distillation Residue
10.1 This procedure is applicable to light distillate oils, such as ASTM No. 1 and No. 2 fuel oils.
10.2 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 the IP Thermometer Specifications is recommended.
10.3 Place a volume of sample equivalent to 200 mL at 13 to 18°C in the flask. Maintain the condenser bath at 0 to 4°C (for some oils it may be necessary to hold the temperature between 38 and 60°C to avoid solidification of waxy material in the condenser tube). Use, without cleaning, the cylinder from which the sample was measured as the receiver and place it so that the tip of the condenser does not touch the wall of the cylinder.
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 after initial application of heat. After the first drop falls, move the receiving cylinder so that the tip of the condenser tube touches the wall of the cylinder. Then regulate the heat so that the distillation proceeds at a uniform rate of 8 to 10 mL/min. Continue the distillation until 178 mL of distillate has been collected, then discontinue heating and allow the condenser to drain until 180 mL (90 % of the charge to the flask) has been collected in the cylinder.
10.5 Immediately replace the cylinder with a small Erlenmeyer flask and catch any final drainage in the flask. Add to this flask, while still warm, the distillation residue left in the distilling flask, and mix well. The contents of the flask then represents a 10 % distillation residue from the original product.
10.6 While the distillation residue is warm enough to flow freely, pour approximately 10 more or less 0.5 g of it in the previously weighed crucible to be used in the carbon residue test. After cooling, determine the weight of the sample to the nearest 5 mg and carry out the carbon residue test in accordance with the procedure described in Section 8.
