API MPMS 10.6 2013 pdf download.Manual of Petroleum Measurement Standards Chapter 10.6 Standard Test Method for Water and Sediment in Fuel Oils by the Centrifuge Method (Laboratory Procedure).
1. Scope* 1.1 This test method describes the laboratory determination of water and sediment in fuel oils in the range from 0 to 30 % volume by means of the centrifuge procedure. N OTE 1—With some types of fuel oils such as residual fuel oils or distillate fuel oils containing residual components, it is difficult to obtain water or sediment contents with this test method. When this situation is encountered, Test Method D95 (API MPMS Chapter 10.5) or Test Method D473 (API MPMS Chapter 10.1) may be used. N OTE 2—API MPMS Chapter 10.6 (Test Method D1796) along with API MPMS Chapter 10.3 (Test Method D4007) formerly superseded API Standard 2548. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 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. For a specific precautionary statement, see 6.1. 2. Referenced Documents 2.1 ASTM Standards: 2 D95 Test Method for Water in Petroleum Products and Bituminous Materials by Distillation (API MPMS Chapter 10.5)
3. Summary of Test Method 3.1 Equal volumes of fuel oil and water-saturated toluene are placed in each of two cone-shaped centrifuge tubes. After centrifugation, the volume of the higher density water and sediment layer at the bottom of the tube is read. 4. Significance and Use 4.1 The water and sediment content of fuel oil is significant because it can cause corrosion of equipment and problems in processing. A determination of water and sediment content is required to measure accurately net volumes ofactual fuel oil in sales, taxation, exchanges, and custody transfers. 4.2 This test method may not be suitable for products that contain alcohols that are soluble in water. In cases where the impact on the results may be significant, the user is advised to consider using another test method, such as Test Method D6304. 5. Apparatus 5.1 Centrifuge: 5.1.1 Use a centrifuge capable of spinning two or more filled cone-shaped 203-mm (8-in.) centrifuge tubes at a speed that can be controlled to give a relative centrifugal force (rcf) of between 500 and 800 at the tip of the tubes (see 5.1.6). 5.1.2 The revolving head, trunnion rings, and trunnion cups, including the cushions, shall be soundly constructed to with- stand the maximum centrifugal force capable of being deliv- ered by the power source. The trunnion cups and cushions shall firmly support the tubes when the centrifuge is in motion. The centrifuge shall be enclosed by a metal shield or case strong enough to eliminate danger if any breakage occurs. 5.1.3 The centrifuge shall be heated and controlled thermo- statically to avoid unsafe conditions. It shall be capable of maintaining the sample temperature during the entire process at 60 6 1°C (140 6 1.8°F). The thermostatic control shall be capable of maintaining the temperature within these limits and operate safely if there is a flammable atmosphere. 5.1.4 Electric powered and heated centrifuges must meet all safety requirements for use in hazardous areas.
6.2 Demulsifiers: 6.2.1 Where necessary, use a demulsifier to promote the separation of water from the sample, to prevent water from clinging to the walls of the centrifuge tube, and to enhance the distinctness of the water-oil interface. 6.2.2 When using a demulsifier, it should be mixed accord- ing to the manufacturer’s recommendations and should never be added to the volume of sediment and water determined. Always use the demulsifier in the form ofa demulsifier-solvent stock solution or be premixed with the solvent to be used in the test. 7. Sampling 7.1 Sampling is defined as all steps required to obtain an aliquot ofthe contents ofany pipe, tank, or other system and to place them into the laboratory test container. 7.2 Only representative samples obtained as specified in Practice D4057 (API MPMS Chapter 8.1) and Practice D4177 (API MPMS Chapter 8.2) shall be used for this test method. 7.3 Practice D5854 (API MPMS Chapter 8.3) contains additional information on sampling and homogenization effi- ciency of an untested mixer. Do not use this test method without strict adherence to Practice D5854 (API MPMS Chapter 8.3). 8. Procedure 8.1 Fill each of two centrifuge tubes (5.2) to the 50-mL mark with the well-mixed sample directly from the sample container. Using a pipette, add 50 mL of the water-saturated solvent (6.1). Read the top of the meniscus at both the 50 and 100 mL marks. Stopper the tubes tightly and shake vigorously until the contents are thoroughly mixed. Loosen the stoppers on the tubes and immerse the tubes to the 100-mL mark for 10 min in the bath maintained at 60 6 1°C (140 6 1.8°F).