ASTM D7060 Test Method for Determination of the Maximum Flocculation Ratio and Peptizing Power in Residual and Heavy Fuel Oils (Optical Detection Method)
7. Apparatus
7.1 Integrated Automated Analytical Measurement
System - This test method uses an integrated automated analytical measurement system comprised of a PC–based computer and two titration stations (Fig. 1). See Annex A1 for detailed information.

7.2 The computer controls test sequencing, acquires and accumulates optical probe signal data, provides processing calculations, and automatically produces a report of important test parameters. The computer is capable of controlling one or two independent titration stations.

7.3 Each titration station consists of the following:
7.3.1 Automatic titration unit,

7.3.2 Heater,

7.3.3 Magnetic stirrer,

7.3.4 Optical probe, and

7.3.5 Reaction cell plus lid.

7.4 Magnetic Stirrer/Hotplate, thermostatically controlled.

7.5 Stirring Bar, magnetic, PFTE-coated, 25 mm in length.

8. Reagents and Materials
8.1 Purity of Reagents - Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.

8.2 Asphaltene Solution (3 g/L) - Dissolve 0.15 g of dry asphaltenes in 1-methylnaphthalene and dilute to 50 mL. A procedure to obtain asphaltenes is described in Appendix X2. Prepare fresh daily, as needed.

8.3 Cetane (n-Hexadecane). (Warning - Irritating to respiratory system and skin.)

8.4 Cleaning Solvent, technical grade, 95 % purity, for cleaning. It consists of one of the following:
8.4.1 Tetrahydrofuran, stabilized. (Warning - Extremely flammable. Irritating to eyes and respiratory system.)

8.4.2 Toluene. (Warning - Flammable. Health Hazard.)

8.4.3 Xylene. (Warning - Flammable. Harmful by inhalation and in contact with skin. Irritating to skin.)

8.5 n-Heptane. (Warning - Flammable. Vapor harmful. Vapor may cause flash fire.)

8.6 1-Methylnaphthalene. (Warning - Harmful if swallowed. Irritating to skin.)

8.7 Quality Control (QC) Sample, a stable and homogeneous residual fuel oil. The QC sample contains at least 1 mass % asphaltenes and has approximate viscosities in the range of 180 to 380 mm2/s at 50°C.

9. Sampling and Test Specimens
9.1 Sampling:
9.1.1 Obtain samples in accordance with Practices D4057 or D4177.

9.1.2 Samples of very viscous materials may be warmed until they are reasonably fluid before they are sampled.

9.1.3 Store samples prior to taking test specimens at ambient temperatures.

9.2 Test Specimen Preparation:
9.2.1 Sample Fuel Temperature - Warm viscous samples until they can be mixed readily before opening the storage container. For fuels with a high wax content (high pour point) the temperature shall be at least 15°C above the pour point.

9.2.2 Shake or mix the sample thoroughly. If the sample contains a high content of insoluble matter, filter the sample through a 47-mm diameter glass fiber filter medium (such as Whatman Grade GF/A) using the Test Method D4870 filtration apparatus.

9.2.3 Preparation of Six Specimen Blends - Visually check the reaction cell and the lid for cleanliness. Dissolve specimen in 1-methylnaphthalene in several different ratios of solvent according to Table 1. Prepare the blends shortly before the test procedure. Generally follow the sequence: (1) prepare and test Blends A1 and B1, (2) prepare and test Blends A2 and B2, and (3) prepare and test Blends C, and D.

NOTE 4 - Blends A1 and B1 can be omitted when the coarse determinations are skipped. See also 12.1.1.1.

9.2.3.1 Weigh, according to Table 1, specimen to the nearest 0.01 g into a clean reaction cell and add a PFTE-coated magnetic stirring bar. Place the reaction cell in the center of the preheated (approximately 150°C) magnetic stirrer/hotplate and switch on the magnetic stirrer. Allow the specimen to warm up, until its viscosity is low enough to obtain a smooth stirring performance.

9.2.3.2 Add, according to Table 1, while continuously stirring, an appropriate volume of 1-methylnaphthalene to the nearest 0.01 mL.

9.2.3.3 Put the lid in place. Initiate the test procedure (12.3) within 10 min.

NOTE 5 - Never use excessive force when placing the lid in place.