Standard No.:	GB/T 25964-2010
English Name:	Petroleum and liquid petroleum products—Determination of volume,density and mass of the hydrocarbon content of vertical cylindrical tanks by hybrid tank measurement systems
Chinese Name:	石油和液体石油产品　采用混合式油罐测量系统测量立式圆筒形油罐内油品体积、密度和质量的方法
Chinese Classification:	E30    Petroleum products in general
Professional Classification:	GB    National Standard
ICS Classification:	75.180.30 75.180.30    Volumetric equipment and measurements 75.180.30
Source Content Issued by:	AQSIQ
Issued on:	2011-1-10
Implemented on:	2011-5-1
Status:	valid
Target Language:	English
File Format:	PDF
Word Count:	13000 words
Translation Price(USD):	390.0
Delivery:	via email in 1 business day

GB/T 25964-2010 Petroleum and liquid petroleum products –Determination of volume, density and mass of the hydrocarbon content of vertical cylindrical tanks by hybrid tank measurement systems 1 Scope This standard gives guidance on the selection, installation, commissioning, calibration and verification of hybrid tank measurement systems (HTMS) for the measurement of level, static mass, observed and standard volume, and observed and reference density in tanks storing petroleum and petroleum products in custody transfer application. As it is a matter for the user to decide which measurements (i.e. volume, or mass) are used for custody transfer purposes, this standard includes an uncertainty analysis, with examples, to enable users to select the correct components of an HTMS to address the intended application. This standard is applicable to stationary, vertical cylindrical tanks storing petroleum products with a Reid Vapor Pressure (RVP) below 103.42kPa. This standard is not applicable to pressurized tanks or marine applications. Note 1: The term “mass” is used to indicate mass in vacuum (true mass). In the petroleum industry, it is not uncommon to use apparent mass (in air) for commercial transactions. Guidance is provided on the calculation of both mass and apparent mass in air (see Annex A). Note 2: The calculation procedures in this standard may also be applied to tanks with other geometries, which have been calibrated by a national standard method. Calculation examples of uncertainty analysis for spherical and horizontal cylindrical tanks are given in Annex B. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) to, or revisions, of any of these publications do not apply. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the referenced document applies. GB/T 1884 Crude petroleum and liquid petroleum products - Laboratory determination of density - Hydrometer method (GB/T 1884-2000, eqv ISO 3675:1998) GB/T 1885 Petroleum measurement tables (GB/T 1885-1998, eqv ISO 91-2:1991) GB/T 4756 Petroleum liquids - Manual sampling (GB/T 4756-1998, eqv ISO 3170: 1988) GB/T 18273 Petroleum and liquid petroleum products - Direct static measurements - Contents of vertical storage tanks - Mass measurement by hydrostatic tank gauging (GB/T 18273-2000, eqv ISO 11223-1:1995) GB/T 19779 Petroleum and liquid petroleum products - Calculation of oil quantities - Static measurement GB/T 21451.4 Petroleum and liquid petroleum products - Measurement of level and temperature in storage tanks by automatic methods - Part 4: Measurement of temperature in atmospheric tanks (GB/T 21451.4-2008, ISO 4266-4:2002, MOD)[) GB/T 21451 consists of 6 parts. Currently, only GB/T 21451.4 has been promulgated and implemented, and other parts are being formulated.]) SH/T 0604 Crude petroleum and petroleum products - Determination of density - Oscillating U-tube method (SH/T 0604-2000, eqv ISO 12185:1996) ISO 91-1:1992 Petroleum measurement tables - Part 1: Tables based on reference temperatures of 15℃ and 60℉ ISO 1998 (All parts) Petroleum industry - Terminology ISO 4266-1 Petroleum and liquid petroleum products - Measurement of level and temperature in storage tanks by automatic methods - Part 1: Measurement of level in atmospheric tanks 3 Terms and definitions For the purposes of this standard, the terms and definitions given in ISO 1998 (all parts) and the followings apply. 3.1 hybrid tank measurement system HTMS system which uses product level measured by an automatic level gauge (ALG), the product temperature measured by an automatic tank thermometer (ATT), and the static pressure of the liquid measured by one or more pressure sensors Note: These measurements are used, together with the tank capacity table and petroleum measurement tables, to provide level, temperature, mass, observed and standard volume, and observed and reference density. 3.2 hybrid processor computing device which uses the level, temperature, and pressure measurements of the HTMS, in addition to stored tank parameters, to compute density, volume and mass 3.3 hybrid reference point stable and clearly marked point on the outside of the tank shell, from which the hybrid pressure sensor position(s) is (are) measured Note: The hybrid reference point is measured relative to the datum point. 3.4 zero error of pressure transmitter indication of the pressure transmitter when no pressure difference between input and ambient pressure is applied to the pressure transmitter Note: This value is expressed in units of pressure measurement, such as Pa. 3.5 linearity error of a pressure transmitter deviation of the indicated value of the pressure transmitter in relation to the applied pressure as input to the transmitter Note: This value shall not include the zero error and is expressed in fractional or percent values, related to the applied pressure (i.e. as a fraction or percentage of reading). 4 General precautions 4.1 Safety precautions 4.1.1 General

Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 General precautions 4.1 Safety precautions 4.2 Equipment precautions 5 Selection and installation of system equipment 5.1 General 5.2 Automatic level gauge 5.3 Pressure sensor(s) 5.4 Automatic tank thermometer (ATT) 5.5 Hybrid processor 5.6 Optional sensors 6 Accuracy effects of HTMS components 6.1 General 6.2 Accuracy effects of the ALG 6.3 Accuracy effects of the pressure sensor(s) 6.4 Accuracy effects of the ATT 7 HTMS measurement and calculations 7.1 General 7.2 HTMS Mode 1 7.3 HTMS Mode 2 8 Initial calibration and field verification 8.1 General 8.2 Initial preparation 8.3 Initial calibration 8.4 Verification of hybrid processor calculations 8.5 Initial field verification 9 Regular verification 9.1 General 9.2 Objectives 9.3 Adjustment during regular verification 9.4 Regular verification in volume-based custody transfer application 9.5 Regular verification in mass-based custody transfer application 9.6 Handling out-of-tolerance situations during regular verification of HTMS in custody transfer application Annex A (informative) Calculation overview Annex B (Informative) Measurement accuracy and uncertainty analysis