API MPMS 10.3 2013 pdf free download

API MPMS 10.3 2013 pdf free download.Manual of Petroleum Measurement Standards Chapter 10.3 Standard Test Method for Water and Sediment in Crude Oil by the Centrifuge Method (Laboratory Procedure).
3. Summary of Test Method 3.1 Equal volumes of crude oil and water-saturated toluene are placed into a cone-shaped centrifuge tube. 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 crude oil is signifi- cant because it can cause corrosion ofequipment and problems in processing. Adetermination ofwater and sediment content is required to measure accurately net volumes of actual oil in sales, taxation, exchanges, and custody transfers. It is not anticipated that this test method, which is written with a dedicated laboratory facility in mind, is likely to be used in field test rooms or sample rooms due to safety concerns for proper ventilation and handling. 4.2 This test method may not be suitable for crude oils 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 D4928 (API MPMS Chapter 10.9). 5. Apparatus 5.1 Centrifuge: 5.1.1 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 a minimum of600 at the tip ofthe tubes shall be used (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.
5.2 Centrifuge Tubes—Each centrifuge tube shall be a 203-mm (8-in.) cone-shaped tube, conforming to dimensions given in Fig. 1 and made of thoroughly annealed glass. The graduations, numbered as shown in Fig. 1, shall be clear and distinct, and the mouth shall be constricted in shape for closure with a cork. Scale error tolerances and the smallest graduations between various calibration marks are given in Table 1 and apply to calibrations made with air-free water at 20°C (68°F), when reading the bottom ofthe shaded meniscus. The accuracy of the graduations on the centrifuge tube shall be volumetri- cally verified, before use of the tube. The verification shall include calibration at each mark up to the 0.25 mL mark (as shown in Fig. 2), and at the 0.5, 1.0, 1.5, 2.0, 50.0, and 100 mL marks. The tube shall not be used if the scale error at any mark exceeds the applicable tolerance from Table 1. 5.3 Bath—The bath shall be either a solid metal block bath or a liquid bath ofsufficient depth for immersing the centrifuge tube in the vertical position to the 100-mL mark. Means shall be provided for maintaining the temperature at 60 6 3°C (140 6 5°F). For some crude oils, temperatures of71 6 3°C (160 6 5°F) may be required to melt wax crystals in crude oils. For these crude oils, the test temperature shall be maintained high enough to ensure the absence of wax crystals.
6.2 Demulsifier—A demulsifier should be used to promote the separation of water from the sample and to prevent its clinging to the walls of the centrifuge tube. The recommended stock solution is 25 % demulsifier to 75 % toluene. For some crude oils a different ratio of demulsifier to toluene may be required. Demulsifiers used in the concentration and quantity recommended will not add to the water and sediment volume determined. The solution must be stored in a dark bottle that is tightly closed. 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 the sample into the laboratory test container. 7.2 Only representative samples obtained as specified in Practices D4057 (API MPMS Chapter 8.1) and Practice D4177 (API MPMS Chapter 8.2) shall be used for this test method. 7.3 Sample Mixing—is typically required to obtain a test portion representative of the bulk sample to be tested, but precautions shall be taken to maintain the integrity of the sample during this operation. Mixing of volatile crude petro- leum containing water or sediments, or both, may result in the loss oflight components. Additional information on the mixing and handling of liquid samples can be found in 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 sample directly from the sample container. Using a pipet or other suitable volume transfer device (see 5.4), add 50 6 0.05 mL of toluene, which has been water saturated at 60°C (140°F) or 71°C (160°F) (see 5.3). Read the top of the meniscus at both the 50 and 100-mL marks. Add 0.2 mL of demulsifier solution (6.2) to each tube, using a 0.2-mL pipet or other suitable volume transfer device, such as an automatic pipettor. Stopper the tube tightly and invert the tubes ten times to ensure that the oil and solvent are uniformly mixed.