ASTM D7061 Standard Test Method for Measuring n-Heptane Induced Phase Separation of Asphaltene-Containing Heavy Fuel Oils as Separability Number by an Optical Scanning Device
6. Apparatus
6.1 PC-based Computer, into which the software that controls the apparatus can be loaded. Data is acquired and accumulated on the hard disk in the computer.
6.2 Optical Scanning Device - The apparatus, which should be suitably calibrated to the manufacturer's instructions, consists of a reading head, composed of a pulsed infrared light source that uses a wavelength of 850 nm. A detector is situated opposite from the light source and reads the transmittance through the glass vial containing the specimen. During a scan, the reading head moves up and down along the glass vial and scans the whole vial going up. The transmittance is automatically measured every 0.04 mm. During one measurement, the time interval between each scan shall be 60 s and 16 scans shall be run. The measuring principle is schematically shown in Fig. 1. The measured transmittance along the glass vial is reported every 0.04 mm and is automatically stored on the hard disk in the computer and can be further processed as described in Section 10 and Annex A2 and Annex A3.
6.3 Cylindrical Clear Glass Vial with Screw Cap, 15 mL, 16 mm outside diameter, 12 mm inner diameter, 140 mm high, and of high optical purity shall be used as a sample container. Use once and then discard.
6.4 Pipette, Graduated or Automatic, 5 and 10 mL.
6.5 Graduated Cylinder, 25 mL.
6.6 Clear Glass Bottle with Cap, 250 mL.
6.7 Clear Glass Bottle with Cap, 50 mL.
6.8 Magnetic Bar, TFE-fluorocarbon-coated.
6.9 Magnetic Stirrer.
6.10 Balance, precision +/- 0.01 g.
6.11 Stopwatch, capable of 0.1 s.
6.12 Burette, 25 mL, Grade A.
6.13 Oven, capable of 60°C at +/- 0.1°C.
7. Reagents and Materials
7.1 Purity of Reagents - Reagents of technical grade (99 % purity) and higher are adequate for this test.
7.2 Heptane. (Warning - Flammable. Vapor harmful. Vapor may cause flash fire.)
7.3 Toluene. (Warning - Flammable. Vapor harmful. Vapor may cause flash fire.)
8. Sampling and Test Specimens
8.1 The oil sample drawn for the purpose of this test method shall be representative of the lot of oil. Obtain the sample in accordance with the procedures ofPractice D4057 or D4177, if possible.
8.2 When working with the oil sample in the laboratory, the oil shall be stirred either manually or mechanically until the mixture is homogenous and representative for the whole sample before withdrawing oil for testing.
8.3 When working with solid or highly viscous oils, the oil may be heated (for example, on a heating plate, in an oven, or, if a drum is heated, by an electrical heating belt or steam shed) to obtain a lower viscosity prior to weighing and mixing. It is then important that the whole sample is fluid to ensure a homogenous mixture and that the sample withdrawn is representative of the whole sample.
