API MPMS 10.9:2013 pdf free download.Manual of Petroleum Measurement Standards Chapter 10.9 Standard Test Method for Water in Crude Oils by Coulometric Karl Fischer Titration
9. Sampling and Test Specimens
9.1 Sample Container—It shall be constructed of a material to which water does not adhere with a sealable lid or other mechanism to prevent rain or humidity from contaminating the sample.
9.1.1 If a non-aerating high-speed shear mixer is to be used, the sample container shall be of sufficient dimensions to allow mixing as described in 9.6 and consistent with the sample container used in any mixer efficiency testing.
9.1.2 Ifa circulating sample mixer is to be used, the primary sample container shall be designed for direct connection to the mixing system without transfer to an intermediate sample container. Internals should be constructed to ensure fluid circulation results in efficient homogenization of the sample. This can be accomplished with spray nozzles, dispersion tubes or other proprietary designs.
9.1.3 Sample Container Preparation—The sample container shall be clean and dry prior to use. Inspect the integrity of sample container lid seals.
9.2 Sample Volume—The volume required for a test speci- men to be analyzed is very small (typically 1 mL or less) so the primary constraint for sample volume is that it be sufficient to allow mixing as described in 9.6, and withdrawal of multiple test specimens for repeat testing.
9.3 Sampling Apparatus—Sample lines and other sampling apparatus that comes into contact with the fluid being sampled shall be constructed of a material to which water does not adhere. The apparatus shall be constructed so that water does not collect in deadlegs and low spots. There may be unique requirements specified in the sampling method listed in 9.5. Prior to extracting a sample, sample apparatus should be appropriately purged or cleaned to prevent contamination.
9.4 Sample Storage and Handling—Samples should be properly labeled and secured as appropriate to prevent tamper- ing. Samples can be stored indefinitely as long as the container is constructed to prevent ingress or egress of vapors, and the fluid being tested can be rehomogenized. No additional envi- ronmental constraints apply to properly sealed containers.
9.5 Sampling Method—Representative samples obtained as specified in Practice D4057 (API MPMS Chapter 8.1) and Practice D4177 (API MPMS Chapter 8.2) should be used to obtain the sample.
9.5.1 Sampling Viscous Crude Oil—Application of this method of viscous crude oils may present challenges in two different areas; sample mixing and test specimen extraction. Mixing apparatus may operate less efficiently. It may be difficult or impossible to extract and deliver an exact quantity of test specimen (see Section 15). Equipment or procedure modifications if required may invalidate the precision statement in this method. Validation of any modifications are required.
9.6 Sample Mixing:
9.6.1 In order for the test specimen to be representative of the sample, the sample must first be homogenized. This is accomplished by mixing the sample using an appropriate mixer for a specified period of time. 9.6.2 The mixer shall meet the specifications for the homog- enization test, Practice D5854 (API MPMS Chapter 8.3). Reevaluate the mixer for any changes in the type of crude, volume of crude in the container, the shape of the container, or the mixing conditions (such as mixing speed and time of mixing).
9.6.2.1 For small sample containers and volumes in the 50 to 500 mL range, a non-aerating, highspeed, shear mixer may be used. Use the parameters found to be satisfactory in the Practice D5854 (API MPMS Chapter 8.3) homogenization test.
9.6.2.2 For larger containers and volumes larger than 500 mL, appropriate mixing conditions shall be defined by follow- ing a set of procedures similar to those outlined in Practice D5854 (API MPMS Chapter 8.3) but modified for application to the larger containers and volumes.
9.6.2.3 Ensure the mixer is clean and dry before use.
9.6.3 An excessive rise in temperature during mixing (ex- ceeding 10°C) may result in the loss ofwater or destabilization of the emulsion. Record the temperature of the sample imme- diately before and after mixing. API MPMS 10.9 pdf download.API MPMS 10.9:2013 pdf free download
