1、Manual of Petroleum Measurement StandardsChapter 11Physical Properties DataSection 2, Part 5A Simplified Vapor PressureCorrelation for Commercial NGLsASTM Technical Publication Stock No. PETROLTBL-TP15GPA Technical Publication TP-15SEPTEMBER 2007REAFFIRMED, AUGUST 2012Manual of PetroleumMeasurement
2、StandardsChapter 11Physical Properties DataSection 2, Part 5A Simplified Vapor PressureCorrelation for Commercial NGLsASTM Technical Publication Stock No. PETROLTBL-TP15GPA Technical Publication TP-15Measurement CoordinationSEPTEMBER 2007REAFFIRMED, AUGUST 2012Prepared forAmerican Petroleum Institut
3、e1220 L Street, NWWashington, D.C. 20005ASTM International 100 Barr Harbor DriveWest Conshohocken, PA 19428Gas Processors Association6526 E. 60th StreetTulsa, OK 74145ii Foreword The purpose of this procedure is to provide a simplified means of estimating equilibrium vapor pressures of various natur
4、al gas liquids (NGLs) from a knowledge of the fluids relative density (60F/60F) and process temperature. The intended application of this procedure is to provide the values of Pe(equilibrium vapor pressure) required to determine the pressure effect contributions to volume correction factors as speci
5、fied in the American Petroleum Institute Manual of Petroleum Measurement Standards (MPMS) Chapter 11.1-20041(which superseded Chapter 11.2.1-19842) and Chapter 11.2.23. It is realized that other equations of state are currently in use for specific custody transfer applications and that such methods
6、will continue to be used as acceptable for both buyer and seller. This procedure is applicable to four major classifications of petroleum fluid mixtures: commercial propanes, commercial butanes, natural gasolines, and light end fluids.The latter consists of EP mixes and high ethane content fluids. I
7、t covers the relative density range of 0.350 to 0.675 over a temperature range of 50F through 140F. This procedure is an extension of GPA Technical Publication TP-15 (1988)9/API MPMS Addendum to Chapter 11.2.2-19944to include light end fluids in the relative density range of 0.350 to 0.490. Variatio
8、ns from the computed vapor pressures to the actual values are to be expected because of the infinite number of possible compositions that can result in the same relative density product. Representative and extreme compositions were selected to develop the correlations, but it is realized that additi
9、onal streams with compositions from among the infinite potential may well behave differently. This potential for variation is especially true at relative densities in the neighborhood of 0.500. For example, at a relative density of 0.505 the fluid could be propane or Y-grade mix, each having signifi
10、cantly different compositions and vapor pressure behaviors. As is always the case in correlations published for custody transfer and settlement purposes, additional accuracy may be obtained by developing a modified correlation for certain specific applications if agreed to by all contracting parties
11、. An equation to improve the accuracy of the generalized correlation at 100F is also included. It is important to note that the application of the correlations presented in this document to conditions or fluids not specified, will result in untested and unknown results which could contain significan
12、t errors. Nothing contained in any API publication is to be construed as granting any right, by implication or otherwise, for the manufacture, sale, or use of any method, apparatus, or product covered by letters patent. Neither should anything contained in the publication be construed as insuring an
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20、desiring to do so. This publication is an updated version of MPMS Addendum to Chapter 11.2.2. Previous editions of this publication were numbered MPMS Addendum to Chapter 11.2.2. Users of this standard should take efforts to ensure they are using the most current version of this publication. Every e
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30、 Table of Contents Foreword _ii API Special Notes _ iii ASTM Note _ v GPA Disclaimer _ vi Table of Contents _ vii List of Tables_ viii List of Figures_ viii 0 Implementation Guidelines _ 1 1 Background _ 1 2 Vapor Pressure Correlation for Commercial NGLs_ 2 3 Correlation Development_ 3 3.1 Propanes
31、_ 7 3.1.1 Product Specifications _ 7 3.1.2 Data Collection_ 8 3.1.3 Data Regression _ 8 3.1.4 Error Analysis _ 8 3.2 Butanes _ 11 3.2.1 Product Specifications _ 11 3.2.2 Data Collection_ 11 3.2.3 Data Regression _ 12 3.2.4 Error Analysis _ 12 3.3 Natural Gasolines _ 15 3.3.1 Product Specifications _
32、 15 3.3.2 Data Collection_ 15 3.3.3 Data Regression _ 17 3.3.4 Error Analysis _ 17 3.4 Light Ends _ 19 3.4.1 Product Specifications _ 19 3.4.2 Data Collection and Validation _ 20 3.4.3 Data Regression _ 22 3.4.4 Error Analysis _ 25 4 Ad Hoc Improvement of the Correlation For Specific Situations _ 25
33、 5 List of References_ 26 viii List of Tables Table 1: Parameters for Vapor Pressure Correlation (Use in Equation 2) 3 Table 2: GPA Liquefied Petroleum Gas Specifications: GPA Standard 2140-8877 Table 3: Correlation Parameters for Propanes and Butanes 9 Table 4: SRK Interaction Parameters for Propan
34、es and Butanes 9 Table 5: Compositions and Relative Densities of Propane Samples 9 Table 6: Comparison of Vapor Pressure Correlations for Commercial Propanes. 10 Table 7: Compositions and Relative Densities of Butane Samples Data Regression 12 Table 8: Comparison of Vapor Pressure Correlations for C
35、ommercial Butanes. 13 Table 9: GPA Standard 3132-84, “Natural Gasoline Specifications and Test Methods” 15 Table 10: Grades of Natural Gasoline as specified by the GPA . 15 Table 11: Correlation Constants for Natural Gasolines 16 Table 12: SRK Interaction Parameters for Natural Gasolines. 16 Table 1
36、3: Compositions and Relative Densities of Natural Gasolines 17 Table 14: Comparison of Vapor Pressure Correlations for Natural Gasolines . 18 Table 15: Compositions of Components Used to Generate Data for Light Ends Correlation. 21 Table 16: Representative Comparison of Vapor Pressures Obtained from
37、 HYSYS with those from NGLCALC 22 Table 17: Representative Comparison Between HYSYS SRK Vapor Pressures and Vapor Pressures from the Correlation for Light End Fluids . 23 List of Figures Figure 1: Vapor Pressures from Correlations5 Figure 2: “A” Parameter (Equation 2 & Table 1)6 Figure 3: “B” Parame
38、ter (Equation 2 & Table 1).6 Figure 4: Maximum Temperature vs Relative Density.21 1 A Simplified Vapor Pressure Correlation for Commercial NGLs 0 Implementation Guidelines This Revised Standard/Technical Publication is effective upon the date of publication and supersedes all previous revisions of t
39、he Standard/Technical Publication and API MPMS 11.2.2A/GPA TP-15. However, due to the nature of the changes in this Revised Standard/Technical Publication and the fact that it is or may be incorporated by reference in various regulations, it is recognized that guidance concerning an implementation p
40、eriod may be needed in order to avoid disruptions within the industry and ensure proper application. As a result, it is recommended that this Revised Standard/Technical Publication be utilized on all new and existing applications no later than TWO YEARS after the publication date. An application, fo
41、r this purpose, is defined as the point where the calculation is applied. Once the Revised Standard/Technical Publication is implemented in a particular application, the Previous Standard/Technical Publication will no longer be used in that application. However, the use of API standards and ASTM and
42、 GPA technical publications remains voluntary and the decision on when to utilize a standard/technical publication is an issue that is subject to the negotiations between the parties involved in the transaction. 1 Background The transfer of ownership of liquids is usually based on the volume of liqu
43、id at agreed upon standard conditions, usually 60F for the U.S. customary system of units and the greater of one atmosphere pressure or the equilibrium vapor pressure of the liquid. Actual measurement of the liquid volumes and the their associated densities occurs at flowing or process conditions. Thus these measurements must be converted to equivalent values at the standard conditions. Once the liquid densities are converted, the conversion of the volumes becomes a trivial exercise. Densities are normally converted from measured conditions to standard conditions by equations of t
