Tiêu chuẩn iso 06578 1991 scan

ISO 6578 INTERNATIONAL STANDARD First edition 1991-12-01 Refrigerated measurement Hydrocarbures hydrocarbon liquids - Static - Calculation procedure liquides r&frig&s - Mesurage statique - Prochdure de calcul Reference number ISO 6578 : 1991 (El `,,`,-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 6578 : 1991 (E) Contents Scope Normative references Definitions and Symbols Volume of LPG at Standard temperature Mass Energy content (calorific content) Inter-conversion of liquid mass and vapour volume at Standard conditions Calculation of liquid density from composition Calculation of calorific value from composition Annexes 10 Orthobaric molar volumes of individual components of LNG 11 Correction factors for volume reduction of LNG mixtures 12 Gross calorific values for individual components 14 Constants for density calculation Relative molecular masses and compressibility factors of individual components 15 Chemical names corresponding to the Chemical formulae used in this International Standard 16 Alternative equation for calculating the molar volume and saturated density of LPG mixtures 17 Critical temperature, acentric factor and characteristic volume of individual comoonents , - used -_ -.in eauations 20 ISO 1991 All rights reserved No part of this publication may be reproduced or utilized in any form or by any means, electronie or mechanical, including photocopying and microfilm, without Permission in writing from the publisher International Organization for Standardization Case postale 56 l CH-1211 Geneve 20 l Switzerland Printed in Switzerland ii Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale `,,`,-`-`,,`,,`,`,,` - Page ISO6578:1991 (EI Foreword `,,`,-`-`,,`,,`,`,,` - ISO (the International Organization for Standardization) is a worldwide federation of national Standards bodies (ISO member bodies) The work of preparing International Standards is normally carried out through ISO technical committees Esch member body interested in a subject for which a technical committee has been established has the right to be represented on that committee International organizations, governmental and non-governmental, in Iiaison with ISO, also take part in the work ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization Draft International Standards adopted by the technical committees are circulated to the member bodies for voting Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote International Petroleum Standard ISO 6578 was prepared by Technical Committee produc ts and lubrican ts Annexes A to H form an integral part of this International Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale Standard ISO/TC 28, ISO 6578 : 1991 (E) lntroduction Storage and transport of large quantities of refrigerated hydrocarbon liquids [e.g liquefied natura1 gases (LNG) and liquefied Petroleum gases (LPG)] is now common practice Existing Standards for the measurement of Petroleum products are either not applicable to, or in some cases inadequate for, these products at low temperatures and, for these products, such Standards shall be replaced or modified by the procedures in this International Standard Accurate measurement is essential in the sale, purchase and handling of refrigerated hydrocarbon liquids Custody transfer agreements call for the standardization of static measurement procedures, and it is recommended that quantities be expressed in mass or energy units lt is recognized that other units are currently used for LPG transfers, but these are not covered in this International Standard Although the principles of calculating the quantity of a static refrigerated hydrocarbon liquid are basically similar to those for Petroleum liquids at ambient temperatures, there are differentes caused by the low temperature and the physical properties of refrigerated hydrocarbons These include the following : a) The liquid product is at or near a temperature at which bubbles of vapour are first formed within the liquid (bubble Point) In a tank containing refrigerated liquid there will always be a small inward flow of heat through the insulation, which will Cause a continuous vaporization of the product The vapour will contain a higher concentration of more volatile constituents than the liquid To avoid over-pressure, this vapour is vented from the tank and tan be compressed, cooled and re-liquefied for re-introduction into the tank b) When a liquid product is transferred from one tank to another, additional heat inflow will occur in the Pipeline and also from work done by the pump, causing additional evaporation in the receiving tank `,,`,-`-`,,`,,`,`,,` - c) For custody transfers from a supply to a receiving tank, it is normal practice to provide a vapour return line linking the tanks to avoid displacement of vapour to the atmosphere Build-up of pressure in the interlinked System is avoided by reliquefaction d) After a partial may occur in the measuring Points Operation is such filling, stratification into different temperature and density layers liquid contents of a tank Therefore, a number of temperature and a special sampling System may be necessary If the filling as to ensure mixing, these needs may be reduced e) There is considerable evidente that large temperature gradients exist in the vapour space of any tank containing a refrigerated hydrocarbon liquid These gradients may not be linear Suitable compensation (physical or by calculation) must be made if the reading of the level-measuring device is affected by differential contraction of the level-Sensor Suspension f) Refrigerated hydrocarbon liquids have large temperature volumetric expansion and approximate values are given below: - propane 0,20 %/“C - methane 0,35 %/OC coeff icients of lt is very strongly emphasised that errors in temperature measurement tan account for the major part of the error in quantitative measurement and the greatest care is therefore needed in the selection and use of temperature measuring equipment This International Standard is applicable to the measurement of refrigerated Iiquids contained in land storage tanks and in ships’ tanks when the liquids are fully refrigerated at a vapour pressure near to atmospheric pressure However, it is not intended that this International Standard be applied retroactively to existing business contracts, nor should it be applied if it is in conflict with government regulations iv Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO6578:1991 (E) No recommendations are given for the measurement of small pa rcels of refrigerated liqu ids, which are directly weighed Calculation procedures for refrigerated hydrocarbon liquids consisting predominantly of ethane or ethylene, or for partially refrigerated hydrocarbon liquids at pressures substantially above atmospheric, are not included Consideration should be given to their inclusion in a subsequent revision, as and when more reliable data become available In Order to implement the detailed recommendations given in this International Standard, it is essential that Personne1 responsible for the measurement procedures have the necessary experience and skill At all times, scrupulous attention must be given to detail NOTE - Use of units: a) Temperature - Celsius temperature is used in connection with the measurement and transport of refrigerated gases and has been used in general in this International Standard; however, in some calculations the thermodynamic, i.e kelvin, temperature scale must be used For accurate conversion, 273,15 K = OC-should be used, but in the examples given here 273 K = OC is sufficiently accurate b) Pressure - The Pascal (Pa) is used as the unit of pressure in this Standard, but the bar is given as an alternative unit The bar may be substituted in calculations; the conversion bar = 100 kPa should be used `,,`,-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale This page intentionally `,,`,-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale left blank INTERNATIONAL STANDARD Refrigerated Calculation ISO 6578 : 1991 (E) hydrocarbon procedure liquids Scope 1.1 This International Standard specifies the calculations to be made to adjust the volume of a refrigerated hydrocarbon liquid, such as LPG or LNG, from the conditions at measurement to the equivalent volume of liquid or vapour at a Standard temperature and pressure, or to the equivalent mass or energy (calorific content) lt applies to quantities of refrigerated hydrocarbon liquids stored in or transferred to or from tanks and measured under static storage conditions by tank gauges 1.2 Using these procedures, the final quantity shall be expressed in terms of the following : a) mass (see the note); b) energy (calorific content) ; c) equivalent ditions volume of vapour under Standard con- NOTE - The current practice for measurement of LPG is by apparent mass in air The factors in table may be used to convert mass into apparent mass in air - Static measurement 1.4 If, for quantity calculations, the product density or the calorific value is required, this shall be either determined directly or calculated from the product composition analysis The procedures for these subsidiary calculations are given in clauses and 1.5 The mandatory basic data and Source references used in the calculation procedures are given in annexes A to F Normative references The following Standards contain provisions which, through reference in this text, constitute provisions of this International Standard At the time of publication, the editions indicated were valid All Standards are subject to revision, and Parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the Standards indicated below Members of IEC and ISO maintain registers of currently valid International Standards ISO 91-1 : 1982, Petroleum Tables based on reference ISO 91-2 : 1991, Petroleum Tables based on reference Table Density at 15 OC kg/m3 500,o 519,2 542,2 567‘4 595,l 625,6 to to to to to to 519,l 542,l 567,3 595,0 625,5 659,3 Factor 0,997 0,997 0,997 0,998 0,998 0,998 75 85 95 05 15 25 measurement tables - Part : temperatures of 15 OC and 60 OF measurement tables temperatures of 20 OC ISO 3993 : 1984, Liquefied Petroleum of density carbons - Determination Pressure h ydrometer method ISO 5024 : 1976, Petroleum ment 1.3 If it is required to express the volume of liquid at a standard temperature, the procedures and correlations to determine such quantities are given in clause The Standard reference temperature for Petroleum products is 15 OC (see ISO 5024), but references are made to calculations involving other widely used reference temperatures, i.e 20 OC 3.1 - Standard Definitions reference Part 2: gas and light hydroor relative density - liquids and conditions gases - Measure- and Symbols Definitions For the purposes of this International Standard, the following definitions shall apply Definitions are given for those terms which have particular relevante in calculation procedures used for refrigerated hydrocarbon liquids ‘1 1) An International Standard (ISO 4273) dealing with terms relating to Petroleum measurement is to be published `,,`,-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS - Not for Resale :1991 (E) 3.1.1 refrigerated hydrocarbon liquids : Liquids composed predominantly of hydrocarbons, which are stored in a fully refrigerated condition at pressures near atmospheric H s i/i is the gross (superior) calorific value’ on a volume basis (ideal), in megajoules per cubic metre, of component i (see annex D); 3.1.2 liquefied natura1 gases predominantly of methane H s,vol is the gross (superior) calorific value on a volume basis, in megajoules per cubic metre, of the vapour at the appropriate Standard temperature and pressure; (LNG): Liquids composed 3.1.3 Iiquefied Petroleum gases (LPG) : Liquids composed predominantly of any of the following hydrocarbons or mixtures thereof : propane, propene, butanes and butene m is the mass, in kil ograms, of product transferred, liquid plus vapou r; is the mass, in kilograms, of liquid; mliq 3.1.4 gross calorific value (specific energy) on mass basis: The number of heat units generated when unit mass of a product in the vapour Phase at Standard temperature and pressure is burned completely in dry air The gaseous products of combustion are brought to the same Standard conditions of temperature and pressure but the water produced is condensed to liquid in equilibrium with water vapour 3.1.5 gross calorific value (specific energy) on volume basis: The number of heat units generated when unit volume of a product in the vapour Phase at Standard temperature and pressure is burned completely in dry air The gaseous products of combustion are brought to the same Standard conditions of temperature and pressure but the water produced is condensed to liquid in equilibrium with water vapour 3.1.6 orthobaric density : The mass of the liquid occupying unit volume at a given temperature, the liquid being in equilibrium with its vapour 3.1.7 densitometer : An instrument for measuring density 3.1.8 volume basis (ideal) : A volume calculated basis that the vapour behaves like an ideal gas on the 3.1.9 volume basis (real) : Volume calculated on the that the vapour behaves like a super-compressible gas 3.1.10 compressibility factor: The ratio of the real volume of a given mass of gas at a specified temperature and pressure to its volume under the same conditions calculated from the ideal gas law 3.2 Mi is the molecular mass, in kilograms per kilomole, component i (see annexes E and GI; M mix is the relative molecu Iar mass, in kilograms kilomole, of the vapour mixture; H s,m,i is the gross (superior) calorific value on a mass basis, in megajoules per kilogram, of component i (see annex D); Q is the net enwy, in megajou les, transferred, gross calorific value ; on Qliq is the energy (calorific) content, in megajou les, of the liquid ; is the temperature, in degrees Celsius, of the liquid; Ts is the Standard reference temperature, (15 OC); Tvap is the temperature, Container; i.e 28%15 K in kelvins, of the vapour in the is the molar volume, in cubic metres per kilomole, of component i, as a liquid at temperature t OC; bq is the volume, temperature t; in cubic metres, of the liquid at Vm is the ideal gaseous molar volume, in cubic metres per kilomole, at Standard conditions of pressure and temperature : i.e 22,413 m3/kmol at Ps and 273,15 K (0 OC); 23,644 m3/kmol at Ps and T, ; Vw is the vapour volume, tainer ; in cubic metres, in the con- Xi ; are the mole fractions of the components respectively ; Xj is the mole fraction of methane in the LNG; is the mole fraction of nitrogen in the LNG; Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Per P vap is the pressure, in kilopascals (bar& of the vapour in the Container; ~1 H s,m is the gross (su perior) calorific value ona mass basis, in megajoules per kilogram, of the liquid ; of Ps is the Standard reference pressure, i.e 101,325 kPa (1,013 25 bar) ; Symbols The following Symbols are defined here for use in this International Standard, but additionally some Symbols are given a more restricted meaning when used in some equations The restricted meaning is then given after the equations i.e Not for Resale i and j, `,,`,-`-`,,`,,`,`,,` - ISO6578 ISO 6578 : 1991 (E) `,,`,-`-`,,`,,`,`,,` - Zi is the compressibility factor for component quired pressure and temperature ; i at the re- Mass 5.1 z mix is the compressibility factor for the vapour mixture under known conditions of temperature and pressure; Mass Volume of LPG at Standard temperature The procedure for converting the volume of refrigerated LPG to its equivalent volume at a Standard temperature and corresponding equilibrium pressure includes the following aspects : a) Very large factors may have to be applied for the correction of observed density to density at Standard temperature, e.g a correction for the effect of a temperature differente of 60 OC may be necessary for refrigerated propane Provided that the LPG does not contain more than 20 % of unsaturated hydrocarbons the correction tables referred to in ISO 91 shall be used for volume corrections However, the tables for this density range are those retained from the 1952 edition of the API-ASTM-IP Petroleum Measurement Tables (sec sub-clause 3.4 of ISO 91-1 : 1982) If the LPG contains 20 % or more of unsaturated hydrocarbons, the density shall be calculated using the method given in clause b) The equivalent liquid content in the vapour space of a Container holding refrigerated LPG is significantly less than if the tank and contents are at ambient temperature Therefore, any error in accounting for the equivalent liquid content in the vapour space will be of lesser significance NOTES The following examples illustrate the magnitud e of errors that tan be introduced by using the tables referred to in IS 91 a) Pure butene or propene: the maximum error will be approxi+20°C; mately % for a correction from -6OOCto b) Mixtures containing aPPIroximately 20 % of unsaturated hydrocarbons a typical error will be approxima tely 0,l % for a temperature differente of 20 OC A condition in which a liquid has a vapour pressure significantly higher than atmospheric pressure at a Standard temperature of 15 OC (or 20 OC or 60 OF) tan only be considered as a pseudo-condition, and the volume of the liquid in this condition may be used only when convenient in a procedure for obtaining the density at refrigerated temperatures by means of pressure hydrometer measurement at ambient conditions (see ISO 3993) Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS using mliq = Viq Q where hq and Q are for the same value of the temperature t EXAMPL E Measured volume of liquid LNG in a Container = 45 550 m3 at a temperature of - 163,5 OC NOTE - Other units may be used for the calculations in this International Standard, provided that they are dimensionally consistent, but vapour temperature and pressure should be expressed in absolute units Phase 5.1.1 Calculate the mass of liquid (miiq), in kilograms, the equation et is the density, in kilograms per cubic metre, of the liquid at temperature t Additional subscripts : F and I indicate, respectively, the final and initial measurements or product properties in either of the two Containers used for a transfer of liquid Calculated density at - 163,5 OC = 468,3 kg/m3 Mass of LNG (mliq) = 45 550 x 468,3 kg = 21,33 x 106 kg or 2133 x i03 t 51.2 The density at a specified temperature shall be measured using either a pressure hydrometer (LPG) or a suitable densitometer, or shall be calculated from a comPosition analysis (see clause 8) If the actual temperature t2 at measured does not differ by more temperature tl of the main bulk of liquid the observed density may be corrected temperature by means of the equation 5.1.3 et,1 = IQ et,1 and which the density is than OC from the in the Container, then to the required bulk (2) + Fl t2 - t,) et,2 are the densities at temperatures t, and t2 respectively ; F is the density correction factor applicable to the particular liquid The units of F shall be compatible with the units of Q, e.g when Q is expressed in kilograms per cubic metre, F is expressed in kg/(m3moC) F kg/(m3- OC) Product LNG [ >80 % (mlm) methanel Liquid propanes [ >60 % (mlm) propane] Liquid butanes [ >60 % (mlm) butane] 114 12 111 EXAMPL E The density of the LNG is 464,8 kg/m3 at t2 = - 161,O OC What is the density of the LNG at - 163,5 OC ? Substituting et,1 into equation (2) gives + 1,4[-161,0 = 464,8 + 3,5 = 468,3 kg/m3 = 464,8 - (-163,5)] The density of refrigerated LPG may be determined at the Standard temperature of 15 OC (or 20 OC or 60 OF) by use of the pressure hydrometer method (see ISO 3993) 5.1.4 Not for Resale ISO 6578 : 1991 (E) The liquid sample drawn into a suitable Container is allowed to approach ambient temperature under pressure, without loss of vapour, before it is introduced into the hydrometer cylinder Correction for vapour Phase 5.2.1 When a quantity of refrigerated hydrocarbon liquid is transferred, it will be necessary to make a correction for the mass of vapour occupying the volume into which, or from which, the liquid is transferred Assuming that all measurements have been made under liquid equlibrium conditions, the following equation tan be applied to measurements made in either the delivery or the receiving container Mass transferred : = Final mass - Initial mass q F/iiq,F@F + F/vap,F x -X T w, m = - [ bqI@I+bapIx I Mmix ps vmzmix F F - IF1 T, Pvap LX- Mmix Tvap,I ps vmzmix -X I Pvap F L-x- 1 I1 (3) If it is impractical to measure the density of the liquid contents of a tank, @F and eI cannot be determined By using the measured density of the liquid being transferred, however, the simplified equation (3a) tan be employed to calculate the mass of product transferred q Pvap F F/liq X Ps’ Tw, F x V/iq@ - LNG transfer from a Container Volume of liquid LNG transferred at temperature t = 45550 m3 Measured temperature of liquid, t = - 163,5 OC Liquid density at - 163,5 OC = 468,3 kg/m3 Average temperature of vapour after transfer = -118 OC = 155 K Pressure of vapour after transfer = 110 kPa ! lt may be assumed that the molecular mass of the vapour mixture is that of pure methane (obtained from annex B) = 16,042 kglmol Mmix The compressibility factor for the vapour tan be taken as unity, with a resultant error of less than 0,05 % - F P vmzmix I F ’ EXAMPLE t where hq and Q are at the storage temperature m= For measurements in a receiving Container, equation (3a) is strictly valid only if the temperature of the incoming liquid is the same as that already contained in the tank The error involved in this assumption is ata maximum when equal volumes of liquid are involved and is then of the Order of 0,004 % per kelvin for LNG (3a) 16,042 288 110 45 550 x 155 x 101,3 x 23,644 = 21 331 065 - 62 355 = 21 269 x 103 kg or 21 269 t EXAMPL E bq e = b - b (i.e the volume of liquid transferred); is the average density of the liquid which is transferred For a receiving tank which does not already contain hydrocarbon liquid or vapour, equation (3) becomes m= Ts bq,F@ + vvap,F X - Tvw Pvap X pS - vmZmix (3b) If the vapour space is negligibly small in comparison with the liquid volume or the liquid volume is negligibly small in comparison with the vapour space in the initial or final condition in the tanks, the simplified equation (3a) may be used in practice Because the mass of vapour is small compared with the mass of liquid transferred, the accurate knowledge of vapour composition and the use of a compressibility factor are not essential and the ideal gaseous molar volume may be used without correction, and typical Calculate the mass of LPG tra nsf erred from a Container the following conditio ns: Initial Final 45 550 850 Liquid density at 15 OC (kg/m3) 507 507 Vapour space in Container (m3) 950 40 000 Temperature of vapour in Container (K) 233 250 Pressure in Container vapour space (bar) 1,08 1,12 lt may be assumed that the molecular mass of the vapour mixture is the same as that of the liquid and that the compressibility factor is unity, i.e Mmix = 44,153 kg/kmol Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS from a Container Volume of liquid in Container at 15 OC (m3) Mmix X LPG transfer Not for Resale `,,`,-`-`,,`,,`,`,,` - 52 values may be used for the temperature and pressure of the vapour wate ( Tvap , Pvap) and for the molecular mass and compressibility factor of the vapour mixture (Mmix, Zmix) ISO 6578 : 1991 (E) EXAMPL E EXAMPL E Calculate the density at -43 OC of LPG which has the molar composition given in table Component (see annex F) Table Component (sec annex F) V;:at -43 OC [see equation (911 Mole f raction xi 0,009 0,978 0,013 30,069 44,0962 58,123 Table XiMi Xi L$ 0,061 805 0,075 789 0,090 191 0,271 43,126 0,756 0,000 556 0,074 122 0,001 172 - 44,153 0,075 850 1,000 c C xi”i z Density = et = p C xivl: mix xi H s, K i at 1,013 25 bar and 15 OC MJ/kg xiHs I ViI 0,900 0,049 0,029 0,013 0,004 0,001 0,004 37,696 66,035 93,975 121,782 121,428 149,676 33,926 3,236 2,725 1,583 0,486 0,150 0,000 1,000 - 42,106 = 0,997 (see 7.2, example 1) Gross calorific value on gas volume basis Hs IVol = 0,075 850 = 42,106 0,997 `,,`,-`-`,,`,,`,`,,` - 44,153 = 4222 MJ/m3 = 582,l kg/m3 9.2 Calculation composition 9.1 of calorific value basis The gross calorific value, on a mass basis, of a mixture may be calculated from the equation Gas volume basis The gross calorific value, on a gas volume basis, of a mixture may be calculated from the equation H s,vol = Mass from C xiHs,lQ z H s,m = C Hs,m,i (11) mix Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale [C(XiMi) xiMi (12) ISO6578:1991 EXAMPLE (EI Table 16,042 30,069 44,0962 58,123 58,123 72,149 28,013 H s,m,i kPa and 15 OC MJ/kg xi XiMi 0,900 0,049 0,029 0,013 0,004 0,001 0,004 14,438 1,473 1,278 0,755 0,232 0,072 0,112 1 0,786 0,0802 0,069 0,041 0,012 0,0039 0,0061 55,558 51,925 W= 49,541 49,397 49,051 1,000 18,362 1,000 - at101,3 XiMi W= 4,166 3,509 2,039 0,625 0,193 54,216 `,,`,-`-`,,`,,`,`,,` - XiMi Component (sec annex F) Gross calorific value on mass basis of the mixture Hs Im = 54,216 MJ/kg EXAMPL E Table Component (See annex F) XiMi Mi xi XiMi C (XiMi) 101,3 H s,m,i kPa and 15 OC MJ/kg C3H8 "-C4H10 30,069 44,0962 58,123 0,009 0,978 0,013 0,271 43,126 0,756 0,0061 0,976 0,017 51,925 W= 49,541 c - 1,000 44,153 1,000 - C2H6 H - XiMi smri x c (Xi+) 0,317 49,220 0,847 W=4 Gross calorific value on mass basis of the mixture Hs rm = 50,384 MJ/kg .- Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale IS06578: 1991 (E) Annex A (normative) Constants for density calculations [for use in equation (911 Table A.l Component Molecular mass Mi kg/kmol C2H6 C3H8 “-C4bo i-C4H ,o n-c5H 12 i-CF;H,2 “-C6H14 n-C7H 16 C2H4 A B c E 0 8 6 499,0 575,0 637,6 616,7 676,2 666,6 705,o 731,9 502,8 0,99 0,97 0,87 0,97 0,87 OB OB OB 1,09 6000 6000 7000 6000 7000 6000 7000 7000 7000 66 129 186 169 231 222 269 301 44 0,083 0,086 0,099 0,103 0,114 0,115 0,129 0,145 - 42,080 56,107 601,2 657,4 1,02 0,97 7000 7000 126 180 0,080 520 0,093 294 30,069 44,096 58,123 58,123 72,149 72,149 86,176 100,203 28,053 C3H6 n-c& Molar volume, 5, at the reference temperature m3/ kmol Constants 15 OC 992 872 407 183 366 508 820 646 20 OC 0,088 0,088 0,100 0,104 0,115 0,116 0,130 0,146 - 464 104 420 313 215 437 700 551 0,081884 0,094 282 60 OC 0,084 0,086 0,099 0,103 0,114 0,115 0,129 0,145 - 452 940 555 321 455 608 912 743 0,080 692 0,093 401 NOTE - The use of these constants in equation (9) should be restricted to LPG mixtures which are either predominantly propane/propylene temperature range +30 OC to -60 OC or predominantly butane/butylene in the temperature range +30 OC to -20 OC in the Bibliography Hl FRANCIS, A.W., Pressure-temperature liquid density relations of pure hydrocarbons, Industrialand Engineering Chemistry, 49, No 10 (1957) AP/ Research Project 44, Physical Constants of Hydrocarbons, C, to CIo `,,`,-`-`,,`,,`,`,,` - [2] 1,o Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 6578 :1991 (E) Annex B (normative) Orthobaric molar volumes of individual components of LNG Table 6.1 Component (sec annex F) Molecular mass Mi kg/mol CH4 [31 16,042 30,069 44,096 58,123 58,123 72,149 72,149 86,176 28,013 31,998 C$i 613] C3H, [33 n-C4H 10[SI i-C4H Io [33 n-CSH 12[4] i-CSH 12141 n-c&i ,4i4] N2 [33 02 [41 Molar volume 0 8 L$, ms/kmol - 180 OC -175 OC -170 OC - 165 OC -160 OC -155 OC 0,035 0,046 0,060 0,074 0,076 0,089 0,089 0,102 0,038 - 0,036 0,046 0,061 0,075 0,076 0,090 0,090 0,103 0,039 0,036 0,047 0,061 0,075 0,077 0,090 0,090 0,103 0,041 0,029 0,037 0,047 0,062 0,076 0,077 0,091 0,091 0,104 0,044 0,030 0,038 0,047 0,062 0,076 0,078 0,091 0,091 0,104 0,047 0,031 0,038 0,048 0,062 0,077 0,078 0,092 0,092 0,105 0,051 0,032 839 369 953 359 859 111 267 45 022 52 771 324 731 997 384 498 576 73 408 - 315 716 164 459 868 016 107 26 949 891 116 602 926 356 536 642 80 788 80 500 524 046 398 851 058 179 34 043 61 149 942 497 875 352 583 721 89 019 51 -150 OC 0,039 0,048 0,063 0,077 0,079 0,092 0,092 0,106 0,055 0,033 580 806 417 847 374 642 817 02 897 67 - 145 OC - 140 OC 0,040 375 0,041 237 0,049253 0,049 711 0,063 0,078 0,079 0,093 0,093 0,106 0,061 887 342 896 177 372 59 767 0,064 0,078 0,080 0,093 0,093 0,107 0,069 364 843 425 715 930 16 064 NOTES The exact molar volume at any temperature is obtained by interpolation, assuming exact linearity between adjacent values in the table The above values of f$ are the best available at the time of publication and may be amended in the light of work in progress I Bibliography c31 HAYNES, W.M., Conference [41 KLOSEK, HIZA, on LNG, J., and Ist International M.J., and MCCARTY, R.D., Density of LNG for custody transfer, Proceedings Dusseldorf, Germany, F.R., 1977 MCKINLEY, Conference of 5th International C., Densities of liquefied natura1 gas and of the low molecular weight hydrocarbons, Proceedings on LNG, of 1968 `,,`,-`-`,,`,,`,`,,` - 11 Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 6578 :1991 (E) Annex C (normative) Correction factors for volume reduction Table C.l - Correction Molecular mass of mixture factor kl kl x 103, m?kmol C Wi 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 - 180 OC - 175 OC -170 OC -165 OC - 160 OC - 155 OC - 150 OC - 145 OC - 140 OC -0,Ol 0,13 0,25 0,37 0,47 0,55 O,M 0,72 0,81 OB 0,95 1,Ol 1,06 1,ll 1,16 - 0,Ol 0,15 0,29 0,41 0,52 0,62 0,72 0,82 0,92 1,~ 1,07 1,13 1,18 1,23 1,29 - 0,Ol 0,16 0,33 0,45 OB 0,70 0,81 0,92 Im 1,12 1,19 1,26 1,32 1,37 l,U - 0,Ol 0,18 0,37 0,51 0,67 0,79 0,90 1,02 1,16 1,25 13 1,41 1,47 19 IB - 0,Ol 0,21 0,41 03 0,76 WJ 1,Ol 1,15 1,30 1,41 13 13 IB 1,72 1,79 - 0,Ol 0,24 0,47 0,67 o,= ID IJ7 13 1,47 13 IB 1,78 1184 1,92 2,00 -0,Ol 0,28 03 0,76 0,98 1,13 1,32 133 IB 1,78 IB 13 - 0,Ol 0,33 0,66 0,87 1,lO 1,29 1,52 1,68 1,87 2,00 2,13 2,24 2,32 2,42 2,51 - 0,Ol 03 0,76 1,Ol 1,30 1,45 1‘71 1184 2,13 2,U 2,41 2,53 2,62 2,73 2,83 Table C.2 - Correction Molecular mass of mixture factor m3 2,15 2,24 k2 IQ x 103, ms/kmol - 180 OC C xi”i `,,`,-`-`,,`,,`,`,,` - 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 of LNG mixtures 0,ll 0,26 w-0 0s 0,67 0,78 OB 0,98 1,07 1,15 12.2 1,31 1,38 1,47 - 175 OC -170 OC - 165 OC - 160 OC - 155 OC - 150 OC - 145 OC - 140 OC - 0,Ol 0,15 0,32 0,47 0,62 0,76 o,w 1,03 1,13 12 1,31 IN 19 1,59 1,68 - 0,Ol 0,21 0,39 0,57 0,71 0,87 1,Ol 1,15 1,27 13 1s 1,61 1,72 IB 1,93 - 0,Ol 0,29 0s 0,71 0,86 1,Ol 1,16 1,30 IA-5 1,61 1,74 1,87 1,s 2,12 2,24 - 0,02 0,4fj 0,67 OB Im 1,16 1,27 1,42 Im Im -0,03 OB Off34 1,13 13 19 1,65 IB -0,04 0,91 1,05 1,39 1,62 1,85 - 0,05 1,21 1,34 1,76 2,03 2,26 2,51 2,81 3,ll 3,29 3,48 3,71 3,95 4,19 4,45 - 0,07 1,60 1,80 2,04 2,19 233 u-8 z63 Z@ 223 2144 2,m 277 2,95 3,12 zo9 233 233 2,73 2,92 3,lO 3,31 3,51 3,72 22 2,45 2,79 3,13 349 3,74 3,97 4,19 446 4,74 5,03 534 NOTES The exact correction factor at any temperature and molecular mass is obtained by interpolation, assuming exact linearity between adjacent values in the table The above values of correction factors kl and IQ are the best available at the time of publication and may be amended in the light of work in progress The above values of correction factors kl and k2 are expressed as the value derived after multiplying by 103 to avoid an excessive number of noughts in the table When applying the factors, a compensating multiplier of IO-3 should be entered to reduce the above values to the correct magnitude (see example in 8.3) 12 Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 6578 : 1991 (E) Bibliography HAYNES, W.M., Conference HIZA, on LNG, M.J., and MCCARTY, R.D., Density of LNG for custody transfer, Proceedings Dusseldorf, Germany, F.R., 1977 of5th international 13 Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale `,,`,-`-`,,`,,`,`,,` - [31 ISO 6578 :1991 (E) Annex D (normative) Gross calorific values for individual components Table D.1 Component (sec annex F) Gross calorific value on mass basis H s m i (MJ!kg) at 101,325 kPa (1,013 25 bar) and 15 OC Gross calorific value on volume basis (ideal) H s vi WlJ/m3) at 101,325 kPa (1,013 25 bar) and 15 OC Gross calorific value on volume basis (real) (MJ/m3) at 101,325 kPa (1,013 25 bar) and 15 OC 55,558 51,925 50,389 49,541 49,397 49,051 48,939 48,716 48,475 50,315 48,950 48,296 16,519 37,696 66,035 93,975 121,782 121,428 149,676 149,336 177,556 205,432 59,700 87,120 114,61 23,807 37,772 66,608 95,834 126,408 125,715 158,555 157,212 194,795 237,411 60,070 88,550 118,52 24,038 CH4 C2H6 C3H8 "-C4H10 i-C4H ,o n-C5H12 i-C5H ,2 "-C6H14 "-C7H16 C2H4 C3H6 C4H8 (mean) H2S NOTE - The “ideal” calorific values are used for the calculation of calorific values of mixtures as described in 9.1 The “real” calorific values are H s, V,i listed for convenience when pure gases are involved and are derived from Zi ’ Bibliography The calorific values in table D.l are calculated from the Standard heats of reaction at 25 OC given in the following c51 ISO 6976 : 1983, Naturalgas [61 API Research 14 - Calculation of calorific value, density and relative Project 44 `,,`,-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale density publications: ISO 6578 : 1991 (E) Annex E (normative) Relative molecular masses of individual and compressibility components factors Table E.1 Component (sec annex F) Relative molecular kg/kmol 16,042 30,069 44,096 58,123 58,123 72,149 72,149 86,176 100,203 28,053 42,080 56,107 28,013 44,009 34,076 CH4 C2H6 C3H8 “-C4bo i-C4H,, n-C5H 12 i-C,H,, n-C6H 14 n-C7H 16 C2H4 C3H6 C4H8 (mean) N2 CO2 H2S mass Mi Compressibility factor Zi at 101,325 kPa (1,013 25 bar) and15 OC (1 - Zi)'12 09980 09914 09806 09634 09659 0,944 0,949 0,911 0,8653 09939 0,983 09670 09997 0,994 09904 0,044 0,0927 0,139 0,191 0,184 0,236 02238 0,297 0,367 0,078 10 0,127 28 0,181 66 0,017 32 0,075 50 0,098 0 8 6 4 - NOTE - The relative molecular masses are based on that of carbon being 12,011 + 0,001 and that of hydrogen beirigg 1,007 + 0,000 Bibliography [71 AP/ Research [81 MASON, Project 44, Tables 23.2 (1.2001 to 1.2007) D.M., and EAKIN, B.E., Research Bdetin, No 32 (1961) `,,`,-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale 15 ISO 6578 : 1991 (El Annex F (normative Chemical names corresponding to Chemical International Standard formulae Table F.1 Chemical name Formula Methane Ethane Propane Butane Isobutane Pentane Isopentane Hexane lsohexane Heptane Ethene Propene But-1-ene Nitrogen Oxygen Carbon dioxide Hydrogen sulfide CH4 c2H6 C3H8 "-C4H10 i-C4H 1o "-C5H12 i-C5H 12 "-C6H14 i-c&i 14 "-C7H16 C2H4 C3H6 n-c& N2 02 CO2 H2S `,,`,-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale used in this ISO 6578 : 1991 (E) Annex G (normative) i Alternative equation / for calculating the molar of LPG mixtures NOTE - This method is intended for use when agreed between terested Parties Basic e = -0,296 123 ) 0,386 914 g = -0,042 725 h = -0,0480645 f = v* VR,(l - wmix vR2) C xi”i et = vt vR1 = density are constants for equation (16) equations et, Mi and Xi Q= and saturated (14) + a(l - TR)“3 + b( - TR)2’3 - TR) + d(l + c(1 G.2 Equations *R - for mixtures n + - T$4’3 C XiMi = (15) c c T TR = p Tc, mix (18) Xi Ui (19) n (16) 1,000 01 Xi Mi i=l e + flR + gTi + hTi 532 = are as defined in 3.2 (13) `,,`,-`-`,,`,,`,`,,` - G.1 volume Xicc)i = c i=l (17) Vt is the molar volume, in cubic metres per kilomole, of the LPG mixture at temperature t OC; n V* is the characteristic kilomole (see annex H); wmix in cubic metres VR1 is the corresponding-states (see reference [91) ; vR2 Xi Xj Vc Tc,u Tc,mix is the acentric factor for the mixture = c xi Ui where mi is the acentric factor for component annex H); Tc,mix is the mixtu re ; critical T is the temperature, (T = t + 273,15); = V;Tc Iij = (VYr, I il/j”Tc Ij)1’2 is the characteristic Gix cubic metres per kilomole in kelvins, of component in kelvins, j=l (21) i (see function for normal fluids temperature, i=l G-tix is the deviation function for new correlation; T is the critical temperature, (s& annex H); n Per (22) volume of the mixture, in i of the Bibliography BI in kelvins, of the liquid R.W., and THOMSON, G.H., COSTALD (Corresponding states liquid density) equation, Hydrocarbon Processing, Sept 1979 HANKINSON, -1,528 16 -j b = 1,439 07 are constants for equation (15) = -0,814 46 ;= 0,190 454 a= 17 Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 6578 : 1991 (E) G.3 Example (see also example in 8.3) Calculate the density at -43 OC of LPG which has a molar composition given in table G.l : Table G.1 Com- V; Mole fraction ‘ygenf annex F) xi C2H6 0,009 0,978 0,013 C3H8 "-C4H10 AIj Xj Mi T Xi Vy (see qw3 Jqp3 yy2/3 ,y;2/3 annex H) 30,069 44,0962 58,123 c 0,271 43,126 0,756 0,145 0,200 0,2544 44,153 ,SZ “i (see Xi QJi annex H) annex H) 0,001 3122 0,526 32 0,195 698 0,584 90 0,003 307 0,633 64 0,004737 0,572 032 0,008237 0,200 32 0,585 01 0,277 02 0,342 11 0,401 49 0,002 493 0,334 584 0,005 219 034230 305,42 369,82 425,18 0,098 0,153 0,200 0,000 88 0,149 83 0,002 61 0,153 According to equation (20) V&ix = - [X xgq + 3(C xyr2’3)(C xyy3)] = - (0,200 32 + x 0,342 30 x 0,585 01) = 0,200 27 Combining equations (21) and (22) = cc `,,`,-`-`,,`,,`,`,,` - n Tc,mix gives n x.x.J7pT, J I = [(O,OO92 x 0,145 x 305,42) + + (0,009 x 0,978 x 0,145 8”2 x 305,42”2 x 0,200 u2 x 369 821’2) + f + (0,009 x 0,013 x 0,145 81’2 x 305f421’2 x 0,254 4”2 x 425 181’2) + f + (0,978 x 0,009 x 0,200 11’2 x 369f82”‘2 x 0,145 8”2 x 305 421’2) + f + (0,9782 x 0,200 x 369,82) + (0,978 x 0,013 x 0,200 1”2 x 369f82”‘2 x 0,254 4”2 x 425 18”2) + f + (0,013 x 0,009 x 0,254 4”2 x 425f18”‘2 x 0,145 8”2 x 305 42”2) + f + (0,013 x 0,978 x 0,254 41’2 x 425f18”2 x 0,200 1”2 x 369 821’2) + f + (Of0132 x 0,254 x 425,18)1/0,200 27 Tc, mix = 74,104 5/0,200 27 = 370,023 According to equation (17) T TR = Tc, mix where T= t + 273,15 = -43 + 273,15 = 230,15 K Hence TR = - 230,15 = 0,621 99 370,023 (1 - TRI = 0,378 01 18 Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 6578 : 1991 (E) According to equation (15) VR' = - 1,528 16(1 - TR)1'3 + 1,439 07(1 - TR)2'3 - 0,81446(1 - TR) + 0,190 454(1 - TR)4'3 = - 1,528 16 x 0,378 o11'3 + 1,439 07 x 0,378 Oi213 - 0,814 46 x 0,378 01 + 0,190 454 x 0,378 01413 0,391 592 = bl According to equation ( 16) ( - 0,296 123 + 0,386 194 TR - 0,042725 TE - 0,0480645 vR2 = (-0,296 = b2 Ti)l(TR - 1,000 1) 123 + 0,386 194 x 0,621 99 - 0,042 725 x 0,621 992 - 0,048 064 x 0,621 9g3) (0,621 99 - 1,000 01) 0,222 24 = Substitu ting Vkix for V* in equation (13) gives Q= vkx vRl(l - cc)mix vR2) = 0,200 27 x 0,391 592(1 - 0,153 x 0,222 24) Vt= 0,075 752 According et = to equation (14) C - xi”i vt et = 44,153 0,075 752 = 582,9 kg/m3 `,,`,-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale 19 ISO 6578 : 1991 (E) Annex H (normative) Critical temperature, of individual acentric factor and characteristic components used in equations volume Table H.l Critical temperature (see ref [IO]) 190,58 305,42 369,82 425,18 408,14 469,65 460,43 507,43 540,26 282,36 364,76 419,57 126,2 154,58 304,21 373,54 0,0074 0,098 0,153 0,200 0,182 0,252 0,240 0,300 0,350 0,088 0,145 0,192 0,035 0,029 0,237 0,103 K CH4 C2H6 C3H8 n-C4H 10 "C4H10 n-C5H 12 i-C5H12 n-C6H 14 n-C7H 16 C2H4 C3H6 C4H8 N2 02 CO2 H2S Tc,i Acentric factor ui (sec ref [9]) Component Characteristic volume m3/kmol (see ref [9]) 0,099 0,145 0,200 0,254 0,256 0,311 0,309 0,368 0,430 0,131 0,182 0,237 0,090 0,073 0,093 0,099 V* 39 8 12 82 83 41 Bibliography BI tiANKINSON, R.W., and THOMSON, G.H., COSTALD (Corresponding states liquid density) equation, Hydrocarbon Sept 1979 [IO] Engineering Data Book, Gas Processors and Suppliers Association, 9th ed., 1972 (4th revision, 1979) `,,`,-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale Processing, `,,`,-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS This page intentionaliy Not for Resale left blank ISO 6578 : 1991 (E) UDC 665.725 : [531.733 Descriptors calculation : Petroleum products, + 531.751 + 536.61 natura1 gas, hydrocarbons, liquefied Petroleum gases, liquefied natura1 gas, volume measurement, Price based on 20 pages `,,`,-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale rules of