1、 GPA Standard 8173-94 Method for Converting Mass of Natural Gas Liquids and Vapors to Equivalent Liquid Volumes Adopted as Tentative Standard, 1973 Revised 1974-1975 Revised and Adopted as Standard, 1976 Revised 1983 Reprinted 1988 Reprinted 1989 Revised 1990 Reprinted 1994 Gas Processors Associatio
2、n 6526 East 60th Street Tulsa, Oklahoma 741 45 DISCLAIMER GPA publications necessarily address problems of a general nature and may be used by anyone desiring to do so. Every effort has been made by GPA to assure accuracy and reliability of the information contained in its publications. With respect
3、 to particular circumstances, local, state, and federal laws and regulations should be reviewed. It is not the intent of GPA to assume the duties of employers, manufacturers, or suppliers to warn and properly train employees, or others exposed, concerning health and safety risks or precautions. GPA
4、makes no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any federal, state, or municipal regulation with which this publication may conflict, o
5、r for any infringement of letters of patent regarding apparatus, equipment, or method so covered. FOREWORD Measurement by mass is often utilized where conditions in temperature, pressure, intermolecular adhesion, and solution mixing present difficulty in converting volumes from flowing to standard c
6、onditions, such as with ethane, natural gas liquids (NGL), or ethane-propane mixes. Measurement by mass is often preferred for chemical reactions and various processes where the mass ratios of components are of primary interest in effecting control of the operation. This standard was developed joint
7、ly by GPA Section H, Product Measurement and Handling, and the API Committee on Natural Gas Fluids Measurement (COGM). It is published by API as Chapter 14, Section 4 (14.4) of the API Manual of Petroleum Measurement Standards (MPMS). The participation of COGM in developing this standard is grateful
8、ly appreciated and acknowledged. Throughout this publication, the latest appropriate API, GPA, and ANSI Standards are referenced. The user will notice an editorial change in the 1994 edition of this standard; the base temperature in “C was corrected from 15.6 to 15. In addition the absolute density
9、values were updated to coincide with GPA Standard 2145-94. 1 GPA STDxBL73 94 m 3824679 0017214 T24 STANDARD FOR CONVERTING MASS OF NATURAL GAS LIQUIDS AND VAPORS TO EQUIVALENT LIQUID VOLUMES -. SCOPE 1.1 This standard prescribes a method for converting the measured mass of natural gas liquids or nat
10、ural gas vapors at operating conditions to equivalent liquid volumes of the components at 60F and equilibrium pressure for English units, or 15C and equilibrium pressure for SI units. 2. OUTLINE OF METHOD 2.1 Mass is calculated by multiplying consistent units of a measured volume by its absolute den
11、sity, with both volume and absolute density determined at the same flowing conditions. The resulting total mass is converted to individual component volumes using a component analysis and proper values of the absolute density in mass per unit volume of each component at 60F (or 15C) and its equilibr
12、ium pressure. 2.2 Volume and absolute density determination, sampling, and analysis shall be performed as described or referenced in GPA Standard 8182 (API Chapter 14.7). 2.3 The absolute density of pure hydrocarbons in pounds mass per gallon (kg/m3), as stated in GPA Standard 2145, shall he used in
13、 the calculations. Unless contract terms specify herwise, absolute density values shall be from the latest revision of GPA Standard 2145. In the examples in this publication, the absolute density values stated in GPA Standard 2145-94 were used. NOTE 1 - The examples in this publication illustrate ty
14、pical components. In actual practice, ail the components detected that are representative of the measured product stream should be included in the conversion to equivalent liquid volumes. NOTE 2 - if constants for hydrocarbon components which are not presenkd in GPA Standard 2145 are required, the c
15、onstants contained in the Physical Properties chapter of the GPSA Engineering Data Book shall be used If the required constants are not contained in the GPSA Engineering Data Book either, the Am Technical Data Book constants shall be used. 3. PRECAUTIONS 3.1 Equipment, installation, and operations s
16、hall be in accordance with GPA Standard 8182 (API Chapter 14.7); however, the following is reiteratd Accurate dynamic measurement can only be accomplished with a single phase, homogeneous, Newtonian fluid. In order to calculate mass accurately, density determination must be made at essentially the s
17、ame pressure and temperature as the volume measurement. Allowable temperature and pressure deviations are set out in API Chapter 14.6. Density may either be measured directly or calculated in accordance with GPA Standard 8182 (MI Chapter 14.7). Dynamic measurement in the vapor phase must occur at a
18、pressure below the equilibrium pressure (dew point pressure) of the mixture at operating conditions. Dynamic measurement in the liquid phase must occur at a pressure above the equilibrium pressure (bubble point pressure) of the mixture at all actual operating temperatures and composition. This stand
19、ard may also be applied to the measurement of supercritical fluids. Measuring and sampling equipment shall be located where it will not be affected by pulsation, mechanical vibration, and compressor, pump, or control valve generated noise that would adversely affect measurement accuracy. 4. CALCULAT
20、IONS FOR LIQUID AND VAPOR CONVERSION (ENGLISH UNITS) Step 1 - Convert mol percent analysis to weight fraction: Given: Composition analysis (mol percent). Molecular weight constants from GPA Standard 2145. a) Multiply the mol percent of each component by the molecular weight of that component, (1) x
21、(2). b) Divide the resulting product for each component (3) by the sum of the products of all components to obtain the weight fraction of each component (4). (1) (2) (3) (4) sum of Mol Mol Percent Percent X X Com- Mol Molecular Molecular Molecular Weight ponent Percent Weight Weight Weight Fraction
22、0.11 2.14 38.97 36.48 294 8.77 1.71 1.82 7-06 100.00 x 44.010 16.043 30.070 44.097 58.123 58.123 72.150 72.150 87.436* = 4.84 34.33 1171.83 1608.66 170.88 509.74 123.38 131.31 617.30 4372.27 + 4372.27 4372.27 4372.27 4372.27 4372.27 4372.21 4372.21 4372.n 4372.27 = 0.001107 0.007852 0.268014 0.36792
23、3 0.039083 O. 11 6585 0.028219 0.030032 O. 141 185 1.000000 3 - GPA STD*8373 94 W 3824b9 0037235 i60 W Step 2 - Calculate the mass of each component: Given: Total pounds mass = 825,300. 5. CALCULATIONS FOR LIQUIDS AND VAPOR CONVERSION (SI UNITS) Step 1 - Convert mol percent analysis to weight fracti
24、on: Given: Composition analysis (mol percent). Component weight hctions from Step 1. a) Multiply the weight fraction by the total mass to obtain the pounds mass of each component. Molecular weight constants from GPA Standard b) Add the pounds mass of all components to ensure that the sum equals the
25、total pounds mass. Total Component Weight Mas Mas Component Fraction (Pounds) (Pounds) 0.001 107 0.007852 0.268014 0.367923 0.039083 0.1 16585 0.0282 19 0.030032 0.141185 1.000000 x 825,300 825.300 825,300 825,300 825,300 825,300 825,300 825,300 825,300 914 6,480 221,192 303.647 32.255 96,218 23,289
26、 24,785 116,520 825,300 - Step 3 - Calculate the volume of each component at equilibrium pressure and 60F: Given: Absolute density of each component from GPA Standard 2145. Component mass from Step 2. a) Divide the component mass of each component by its absolute density to obtain the equivalent liq
27、uid volume. 2145. a) Multiply the mol percent of each component by the molecular weight of that component, (1) x (2). b) Divide the resulting product for each component (3) by the sum of the products of all components to obtain the weight fraction of each component (4). (1) (2) (3) (4) sum of Mol Mo
28、l Percent Percent X X Com- Mol Molecular Molecular Molecular Weight ponent Percent Weight Weight Weight Fraction coz 0.11 x c, 38.97 Cl 2.14 C, 36.48 IC4 2.94 NC, 8.77 IC5 1.71 NC, 1.82 7.06 6+ 100.00 44.010 16.043 30.070 44.097 58.123 58.123 72.150 72.150 87.436* = 4.84 34.33 1171.83 1608.66 170.88
29、 509.74 123.38 131.31 617.30 4372.27 + 4372.27 4372.27 4372.27 4372.27 4372.27 4372.27 4372.27 437227 4372.27 Step 2 - Calculate the mass of each component: = 0.001107 0.007852 0.2680 14 0.367923 0.039083 O. 116585 0.028:- 0.0301 0.141185 1.000000 Given: Total kilograms mass = 374,350, Component Den
30、sity Component weight fractions from Step 1. Mass (Pound Mass Gallons at Component (Pounds) per Gallon) 60F. EVP CO2 9 14 +- 6.8199 = 134 Cl 6,480 2.5 2,592 c3 303,647 4.2268 71,839 IC4 32,255 4.6927 6,873 NC4 96,218 4.8691 19,761 24,785 5.2614 4,711 6+ 116.520 5.951 * 19,580 204,449 c2 221.1 92 2.9
31、696 74,485 1% 23,289 5.2058 4,474 NC5 * Molecular weight and density of c6+ are calculated from extended analysis as described in GPA Standard 2186 “Tentative Method for the Extended Analysis of Hydrocarbon Liquid Mixtures Containing Nitrogen and Carbon Dioxide by Temperature Programmed Gas Chromato
32、graphy .“ The hexanes-plus component may be reported as hexanes and heptanes-plus. a) Mulitply the weight fraction by the total mass to b) Add the kilograms mass of all components to ensure obtain the kilograms mass of each component. that the sum equals the total kilograms mass. Component Weight Fr
33、action 0.001 107 0.007852 0.268014 0.367923 0.039083 0.1 16585 0.028219 0.030032 0.141185 1.000000 Total MSS (Kilograms) x 374,350 374.350 374,350 374,350 374,350 374,350 374,350 374,350 374,350 Component Mass (Kilogramd 414 2,939 100.33 1 137.732 1453 1 43,644 10,564 11,242 - 52,853 374,350 4 GPA S
34、TD*L73 94 3824699 OOL72Lb 8T7 Step 3 - Calculate the volume of each component at equilibrium pressure at 15C. Given: Absolute density of each component from GPA Standard 2145. Component mass from Step 2. a) Divide the component mass of each component by its absolute density to obtain the equivalent
35、liquid volume. Component Density Cubic MW Kilogram/ Meters Component (Kilograms) Cubic Meter) at 15C. EVP CO2 414 Cl 2,939 c2 100,331 c3 137,732 IC4 14,631 IC5 10,564 6 52,853 374,350 NC4 43,644 NC5 11,242 -+ 821.94 300.00 357.76 507.30 562.98 584.06 624.35 631.00 713.1* .50 9.80 280.44 27 1.50 25.9
36、9 74.73 16.92 17.82 74.12 771.82 - * Molecular weight and density of c6+ are calculated from extended analysis as described in GPA Standard 2186 “Tentative Method for the Extended Analysis of Hydrocarbon Liquid Mixtures Containing Nitrogen and Carbon Dioxide by Temperature Programmed Gas Chromatogra
37、phy.“ The hexanes-plus component may be reported as hexanes and heptanes-plus. APPENDIX References 1. GPA Standard 2145, latest revision, “Table of Physical Constants of Parafin Hydrocarbons and Other Components of Natural Gas.“ 2. API Technical Data Book - Petroleum Refining, latest revision, Chapter I. 3. GPS A Engineering Data Book, latest revision, Physical Properties.
