ASTM D7829-13 (R2018) pdf free download.Standard Guide for Sediment and Water Determination in Crude Oil.
1.1 This guide covers a summary of the water and sediment determination methods from (he API MPMS Chapter H) for crude oils. The purpose of this guide is to provide a quick reference o these methodologies such that the reader can make the appropriate decision regarding which method o use based on the associated benefits, uses, drawbacks and limitations.
1 .2 The values stated in SI units are to he regarded as standard. No other units of measurement are included in this standard.
3. Significance and Use
3.1 Theoretically, all of the sediment and water determination mcthxls are valid for crude oils containing from 0 to 100 k by volume sediment and water; the range of application is specified within the scope of each method. The round robins for all methods were conducted on relatively dry oil. All precision and bias statements included in the methods are based upon the round robin data. Analysis becomes more challenging with crude oils containing higher water contents due to the difficulty in obtaining a representative sample, and maintaining the sample quality until analysis begins.
3.2 Currently. Karl Fischer is generally used for dry crude oils containing less than 5 % water. Distillation is most commonly used frr dry and wet crude oils and where separate sediment analysis is available or in situations where the sediment result is not significant. The laboratory centrifuge methods allow for determination of total sediment and water in a single analysis. The field centrifuge method is used when access to controlled laboratory conditions are not available.
3.3 In the event of a dispute with regard to sediment and water content, contracting parties may refer to the technical specifications table to determine the most appropriate referee method based upon knowledge of and experience with the crude oil or product stream.
4. Pnwedure
4. 1 To obtain the total sediment and water results when the two are determined by separate methods: First, add the raw, unrounded results together, and then round the sum to the correct significant figure.
4.2 It is critically important that the analytical samples are collected and handled with careful regard to ensure that they are representative of the entire parcel. The crude oil or product stream should be hornogenous at the sampling point, and the sample properly mixed prior to analysis. Sub-samples should not be allowed to settle prior to transfer into an analytical device such as a cernrifuge tube, distillation apparatus. or extraction thimble. Refer to API MPMS Chapter 8.1 (ASTM D4057) Standard Practice for Manual Sampling of Petroleum and Petroleum Products. API MPMS Chapter 8.2 (ASTM 1)4177) Standard Practice for Automatic Sampling of Petroleum and Petroleum Products, API MPMS, and Chapter 8.3 (ASTM 1)5854) Standard Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products for appropnate sample collection and mixing.
4.3 It is imperative that every sample is mixed sufficiently to ensure that it is homogeneous. However, with prolonged mixing the temperature of the sample will increase. This will decrease the representative nature of the sample due to evaporative losses.ASTM D7829 pdf download.