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 2007Manual of PetroleumMeasurement StandardsChapter 11Phys
2、ical Properties DataSection 2, Part 5A Simplified Vapor PressureCorrelation for Commercial NGLsASTM Technical Publication Stock No. PETROLTBL-TP15GPA Technical Publication TP-15Measurement CoordinationSEPTEMBER 2007Prepared forAmerican Petroleum Institute1220 L Street, NWWashington, D.C. 20005ASTM I
3、nternational 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 natural gas liquids (NGLs) from a knowledge of the
4、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 specified in the American Petroleum Institute Manua
5、l of Petroleum Measurement Standards (MPMS) Chapter 11.1-20041(which superseded Chapter 11.2.1-19842) and Chapter 11.2.23.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 will continue to be used as acceptable for bot
6、h 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. It covers the relative density range of 0.350 t
7、o 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. Variations from the computed vapor pressures to the ac
8、tual 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 additional streams with compositions from among the
9、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 significantly different compositions and vapor pressu
10、re 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. An equation to improve the accuracy of the g
11、eneralized 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 significant errors. Nothing contained in any API publica
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25、ransmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. Copyright 2007 American Petroleum Institute, Gas Processors Association v ASTM Note This publication does not purport to address all of the safety concerns, if
26、 any, associated with its use. It is the responsibility of the user of this publication to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. vi GPA Disclaimer Neither the GPA nor any person acting on behalf of the GPA makes any
27、warranty, guarantee, or representation, express or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this report. The GPA hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of any apparatus, method, or
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29、ed, stored in a retrieval system, or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. Copyright 2007 American Petroleum Institute, Gas Processors Association vii Table of Contents Foreword _ii API Special No
30、tes _ 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 _ 7 3.1.1 Product Specifications _ 7 3.1.2 Dat
31、a 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 _ 15 3.3.2 Data Collection_ 15 3.3.3 Data Regre
32、ssion _ 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 5 List of References_ 26 viii List of Tables
33、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 Propanes and Butanes 9 Table 5: Compositions and Rel
34、ative 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 Commercial Butanes. 13 Table 9: GPA Standard 31
35、32-84, “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 13: Compositions and Relative Densities of Natu
36、ral 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 HYSYS with those from NGLCALC 22 Table 17: Re
37、presentative 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” Parameter (Equation 2 & Table 1).6 Figure 4: Maximum
38、 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 the Standard/Technical Publication and API MPMS
39、 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 period may be needed in order to avoid disrupti
40、ons 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, for this purpose, is defined as the point where
41、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 GPA technical publications remains voluntary
42、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 liquid at agreed upon standard conditions, usually
43、 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 the form: 60= Ft Fp Equation 1 Where:
