API MPMS 12.3-2006 pdf free download

API MPMS 12.3-2006 pdf free download.Manual of Petroleum Measurement Standards Chapter 12- Calculation of Petroleum Quantities Section 3- Volumetric Shrinkage Resulting From Blending Light Hydrocarbons With Crude Oils .
4 Data and Mathematical Model Selection The data used to derive the correlation presented in this document originated from four separate experimental studies, authored by Childress, Scott, Schuchardt, and Booker. The ranges of density of oil and light hydrocarbon are given in Table 1. The data are described in more detail in Tables B-1 to B-4. Available information on the sources and densities of crudes and light components is included, together with the number of data sets and sum- marized statistical data. Sources of the data are also shown graphically in Figure B-1. The selection of an appropriate mathematical model was based on the ability of differ- ent correlations to predict the experimental results. As expected from the form of the equa- tion, API 2509C performs very poorly above a 25 percent spike. This is apparent from the large deviations between predicted and experimental values (i.e. the absolute residuals) plotted in Figure B-6. Improvement was obtained by selecting the form of correlation equation proposed by Ashcroft et al.8 Figure B-6 shows the average absolute residuals determined using the model of Ashcroft et al., and Figure B-7 plots those obtained by fitting all of the data to an equation of the same form. Statistical differentiation between these latter two equations was achieved using an F-test as suggested by Beck and Arnold. 10 This test confirmed that the new equation presented in this standard gives the best prediction of the available ex- perimental data over the entire range of compositional variation. Data sets that exhibited the anomalous behavior of expansion rather than shrinkage were not used in deriving the new correlation. This included Booker’s toluene and cyclohexane spiked crude data sets and Schuchardt’s results from crude blends with gasoil. The available experimental data were obtained at somewhat different temperatures and pressures.
6 Precautions on Use of the New MPMS Chapter 12.3 Equations and Tables 6.1 EFFECT OF TEMPERATURE AND PRESSURE ON VOLUMETRIC SHRINKAGE The new correlation is based on experimental data gathered at conditions of absolute pressure in the range of 100-700 kilopascals, 15-115 pounds per square inch absolute, and temperatures near 15°C or 60°F. Thus, it is recommended that all shrinkage calculations be limited to conditions within that range. 6.2 DIFFERENCE BETWEEN CUSTOMARY AND METRIC TABLES Shrinkage factors obtained from Table 3 in customary units will not necessarily be nu- merically equivalent to factors determined from Tables 4 and 5 in SI units. This difference is partially the result of the difference in standard temperatures (60°F versus 15°C), but even after volume correction using the API correlation, shrinkage factors may show a rel- ative difference of as much as 0.4 percent. For custody transfer purposes, it is therefore rec- ommended that buyers and sellers agree on which set of tables they will use. 6.3 LIMITATIONS AND ALTERNATIVES The correlation equation or tables given in this text can predict volumetric shrinkage within the stated precision for mixtures of hydrocarbons over a relatively wide range in density difference and mixture ratios. However, the available experimental data suggest that factors other than density difference affect the volumetric behavior. Current under- standing is insufficient to allow accurate prediction of the effect of composition, and thus experimental confirmation is recommended for hydrocarbon types not represented in the existing data sets. It is recommended that when an accurate shrinkage is required for spe- cific mixtures or when there are extenuating circumstances that may make use of the shrink- age tables questionable, the shrinkage may be determined by testing the individual components in a qualified lab using one of the test methods included in Appendix C.