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GB/T 24747-2023 English PDF (GBT24747-2023)

GB/T 24747-2023 English PDF (GBT24747-2023)

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GB/T 24747-2023: Safety technology conditions for organic heat transfer fluid

This document specifies the safety technology conditions for organic heat transfer fluids used by various types of boilers and heat transfer systems with organic heat transfer fluids. This document is applicable to organic heat transfer fluids that use various organic heat transfer fluid boilers, photothermal energy storage or other heating equipment as heating sources and for the purpose of indirect heating. It is inapplicable to organic heat transfer fluids that are only used for freezing and cryogenic cooling, nor is it applicable to organic silicone heat transfer fluid.
GB/T 24747-2023
GB
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 27.060.30
CCS J 98
Replacing GB/T 24747-2009
Safety Technology Conditions for Organic Heat Transfer
Fluid
ISSUED ON: MAY 23, 2023
IMPLEMENTED ON: MAY 23, 2023
Issued by: State Administration for Market Regulation;
Standardization Administration of the PEOPLE Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 6
2 Normative References ... 6
3 Terms and Definitions ... 7
4 General Requirements ... 8
5 Requirements and Test Methods for Quality Indexes ... 9
6 Determination and Disposal ... 11
7 Inspection Cycle and Sampling ... 13
8 Mixed Use ... 14
9 Separation and Disposal of Deteriorated Material ... 15
10 Cleaning of Heat Transfer System ... 15
11 Replacement and Abandonment ... 15
Appendix A (normative) Determination of Acid Value of Organic Heat Transfer Fluid (by potentiometric titration method) ... 17
Safety Technology Conditions for Organic Heat Transfer
Fluid
1 Scope
This document specifies the safety technology conditions for organic heat transfer fluids used by various types of boilers and heat transfer systems with organic heat transfer fluids. This document is applicable to organic heat transfer fluids that use various organic heat transfer fluid boilers, photothermal energy storage or other heating equipment as heating sources and for the purpose of indirect heating. It is inapplicable to organic heat transfer fluids that are only used for freezing and cryogenic cooling, nor is it applicable to organic silicone heat transfer fluid.
2 Normative References
The contents of the following documents constitute indispensable clauses of this document through the normative references in the text. In terms of references with a specified date, only versions with a specified date are applicable to this document. In terms of references without a specified date, the latest version (including all the modifications) is applicable to this document. GB/T 261 Determination of Flash Point - Pensky-Martens Closed Cup Method GB/T 265 Petroleum Products - Determination of Kinematic Viscosity and Calculation of Dynamic Viscosity
GB/T 4756 Method for Manual Sampling of Petroleum Liquids
GB/T 6536 Standard Test Method for Distillation of Petroleum Products at Atmospheric Pressure
GB/T 6682 Water for Analytical Laboratory Use - Specification and Test Methods GB/T 11133 Standard Test Method for Determination of Water in Petroleum Products, Lubricating Oils, and Additives - Coulometric Karl Fischer Titration Method GB/T 11137 Black Petroleum Products - Determination of Kinematic Viscosity (reverse-flow method) and Calculation of Dynamic Viscosity
GB/T 16483 Safety Data Sheet for Chemical Products - Content and Order of Sections GB/T 23800 Heat Transfer Fluids - Determination of Thermal Stability
3.5 liquid phase organic heat transfer fluid
Liquid phase organic heat transfer fluid is a synthetic organic heat transfer fluid and mineral oil organic heat transfer fluid with a certain distillation range, which can only be used under liquid phase conditions.
[source: GB 23971-2009, 3.6, modified]
3.6 maximum working temperature
Maximum working temperature is the maximum temperature of the main fluid of the organic heat transfer fluid allowed at the boiler outlet under the actual operating conditions of the heat transfer system.
NOTE: the average main fluid temperature of the organic heat transfer fluid measured at the boiler outlet is the working temperature.
[source: GB 23971-2009, 3.9, modified]
3.7 initial boiling point; IBP
Initial boiling point is the temperature point, at which, the cumulative area is equal to 0.5% of the total area of the obtained chromatogram when the petroleum fractions boiling range step- by-step method is used for determination.
NOTE: the determination of boiling range distribution of petroleum fractions adopts NB/SH/T 0558.
3.8 low-boiling component
Low-boiling component is the substance whose distillation temperature in the organic heat transfer fluid in use is lower than its initial boiling point when it is unused. 3.9 deteriorated material
Deteriorated material is a general term for substances different from the original properties of the organic heat transfer fluid and generated under the influence of factors, such as: oxidation, overheating and mixture of foreign matters, on the organic heat transfer fluid in use. 4 General Requirements
4.1 The organic heat transfer fluid products shall comply with the requirements of GB 23971. The following documents, for example, product quality certificate, shall be provided at the same time when the organic heat transfer fluid products are sold.
a) Product type test report that complies with GB 23971 and issued by the organic heat transfer type test institution.
b) Exit-factory quality inspection report of the batch of products issued by the manufacturer; if the supplier provides a copy of the report, the authenticity of the report shall be confirmed by the supplier.
c) Safety data sheet for chemical products that complies with the requirements of GB/T 16483.
4.2 The self-ignition point of the organic heat transfer fluid shall not be lower than the maximum permitted bulk temperature.
4.3 The maximum permitted bulk temperature of the organic heat transfer fluid shall be at least 10 ???C higher than the maximum working temperature of the organic heat transfer fluid boiler. For electric heating boilers, coal-fired boilers or boilers with an average heat flux density greater than 0.05 MW/m2 on the radiant heating surface of the furnace, the maximum permitted bulk temperature of the selected organic heat transfer fluid shall be at least 20 ???C higher than the maximum working temperature of the organic heat transfer fluid boiler. 4.4 The organic heat transfer fluid at any point in the heat transfer system shall not exceed the maximum permitted film temperature of the organic heat transfer fluid; the calculated maximum film temperature of the organic heat transfer fluid boiler shall not be higher than the maximum permitted film temperature of the organic heat transfer fluid.
4.5 L-QC and L-QD organic heat transfer fluids shall be used in closed circulation systems; L- QB organic heat transfer fluid can be used in closed or open circulation systems, but the thermal oxidation stability index of the organic heat transfer fluid used in the open circulation system shall be qualified, and the temperature of the organic heat transfer fluid in the expansion tank of the open circulation system shall be lower than 70 ???C during normal operation. See GB 23971 for the classification of L-QB, L-QC and L-QD.
4.6 The organic heat transfer fluids shall not be directly used to heat or cool oxidizing chemicals. The organic heat transfer fluids used for indirect heating in the production of food or medicine shall not only comply with the stipulations of GB 23971, but also satisfy the requirements of relevant national safety standards on food and medicine.
5 Requirements and Test Methods for Quality Indexes
5.1 Verification Indexes and Test Methods for Unused Organic Heat Transfer Fluid
Before the unused organic heat transfer fluid is injected into the system (including the unused organic heat transfer fluid initially injected into the system and the unused organic heat transfer fluid replaced or supplemented after operation), a quality verification inspection shall be carried out in accordance with the product type test report. See Table 1 for the inspection items and test methods.
continuing the use;
d) Within 3 months after replacing or adding different organic heat transfer fluid products in the system.
7.2 Sampling
7.2.1 The sampling of the unused organic heat transfer fluid shall comply with the requirements of GB/T 4756; the sampling volume shall be able to satisfy the requirements of verification inspection and subsequent re-inspection of reserved sample, and the volume of reserved sample shall not be less than 1 L.
7.2.2 The sampling of the organic heat transfer fluid in use shall be carried out through a non- water-cooled sampler in the system circulation loop, and the sampling temperature shall not be higher than 50 ???C. The obtained sample be a uniform sample representing the quality of the organic heat transfer fluid currently in use in the system. The sampling volume shall be able to satisfy the requirements of inspection and re-inspection of reserved sample. The retention time of the reserved sample for re-inspection shall not be less than 40 d.
8 Mixed Use
8.1 The vapor phase organic heat transfer fluids with different chemical compositions shall not be mixed, and vapor phase organic heat transfer fluid and liquid phase organic heat transfer fluid shall not be mixed.
8.2 Generally, organic heat transfer fluids with different chemical and physical properties shall not be mixed in the same system.
8.3 If it is necessary to mix synthetic liquid phase organic heat transfer fluid with mineral oil organic heat transfer fluid, or to mix synthetic liquid phase organic heat transfer fluids with different chemical compositions, and to mix mineral oil organic heat transfer fluids produced by different manufacturers, the following requirements shall be satisfied: a) Pass the thermal stability inspection of GB/T 23800, and have a thermal stability higher than or equivalent to the original organic heat transfer fluid in use; b) Comply with the requirements of Chapter 4;
c) Before adding, pass the verification inspection specified in Table 1; d) The manufacturer or supplier provides relevant test or inspection certificates that the mixed organic heat transfer fluids will not undergo chemical reaction or generate stratification which may affect safe use.
8.4 The quantity and mixing ratio of mixed organic heat transfer fluids added to the heat transfer system shall be accurately recorded, and meanwhile, a sampling inspection shall be carried out on the organic heat transfer fluid after mixing and 1 L of sample shall be reserved for re- inspection.
8.5 The organic heat transfer fluid after mixing shall be used in accordance with the properties and performance conditions of the original organic heat transfer fluid in use, and the quality index shall comply with the requirements of Table 2.
8.6 Various types of additives shall not be added to the organic heat transfer fluid in use, which may change its physical and chemical properties.
9 Separation and Disposal of Deteriorated Material
9.1 For synthetic organic heat transfer fluid in use that still has disposal value, appropriate separation and refining methods can be adopted to separate and dispose the deteriorated material, remove the pollutants and part of the degenerated substances, so as to improve the quality to a certain extent. After reaching the quality index of normal use in Table 2, it can continue to be used in the original system.
9.2 The disposal process shall ensure standardization and safety and comply with the requirements of environmental protection. After the separation and disposal of the deteriorated material is completed, the organic heat transfer fluid in the system shall be sampled and tested. After reaching the quality index of normal use, it can continue to be used. 10 Cleaning of Heat Transfer System
10.1 When the organic heat transfer fluid in the system is seriously polluted, the carbon residue or kinematic viscosity reaches the quality index of discontinued use, or after the boiler tube undergoes an overheating and overtemperature accident, and before an organic heat transfer fluid is replaced in the system, the boiler and the system shall be inspected. If there are remaining pollutants, or coking is generated and residual oil adhesion become serious, which reaches the cleaning conditions of GB/T 34352, then, an appropriate cleaning mode shall be adopted to remove the pollutants in the system and the coking in the boiler tube, so as to keep the system clean and prevent the newly replaced organic heat transfer fluid from being polluted. 10.2 The cleaning and quality of boiler and heat transfer system with organic heat transfer fluids shall comply with the stipulations of GB/T 34352.
10.3 After the organic heat transfer fluid is injected into a cleaned system and the degassing operation is completed, a sampling inspection shall be carried out, and its quality shall comply with the quality index of normal use in Table 2.
11 Replacement and Abandonment
11.1 When the kinematic viscosity, acid value, carbon residue or pollution level of the organic heat transfer fluid in use are within the range of ?€?quality index of discontinued use?€? in Table 2, Appendix A
(normative)
Determination of Acid Value of Organic Heat Transfer Fluid (by potentiometric titration method)
A.1 Overview
A.1.1 The measurement range of this method (by KOH): 0.01 mg/g ~ 30 mg/g. A.1.2 In this method, potassium hydroxide - isopropanol standard solution (hereinafter referred to as KOH standard solution) is taken as the titrant, and a mixed solvent of toluene, isopropanol and a small amount of water is used to dissolve the sample; through a combination electrode or a pair of glass indicator electrodes - silver / silver chloride (Ag/AgCl) reference electrodes, potentiometric titration is performed. In accordance with the volume of the KOH standard solution consumed and the potential value, draw a titration curve, and judge the endpoint and stoichiometric point by the jump point on the curve. When there are many kinds of weak acids in the organic heat transfer fluid, resulting in multiple jump points in the titration process, take the KOH standard solution consumed at the jump point corresponding to the potential value closest to the pH 11 ??? 0.02 standard buffer solution to calculate the acid value for the endpoint judgment; if no jump point can be found during the titration process, then, use the volume of the KOH standard solution consumed when titrated to the potential value measured by the electrode in the pH 11 ??? 0.02 standard buffer solution (hereinafter referred to as EP potential value) to calculate the acid value.
A.2 Instruments
A.2.1 Potentiometric titrator
A.2.1.1 Automatic potentiometric titrator
The basic requirements for the automatic potentiometric titrator are as follows: a) Automatic potentiometric titrator: it shall be able to automatically adjust the addition amount and titration speed of the KOH standard solution in accordance with the change of the titration curve, so as to satisfy the setting requirements of A.6.6; b) Motor-driven burette: with an accuracy of not lower than ??? 0.002 mL; c) Titration mode: ?€?balanced control mode?€?: during the titration process, the potentiometric titration curve and the first-order differential curve shall be drawn at the same time;
d) Mechanical stirrer: propeller stirrer or magnetic stirrer; the stirring speed shall be adjustable, so that it can thoroughly stir the liquid;
e) Reagent bottle containing the KOH standard solution: there shall be a dry tube that can absorb CO2 (the tube contains anhydrous sodium carbonate, soda lime or other substances that can absorb CO2);
f) Titration cup: with a volume of 100 mL, made of borosilicate glass or other materials that will not react with organic heat transfer fluid.
A.2.1.2 Manual potentiometric titrator
The basic requirements for the manual potentiometric titrator are as follows: a) Potentiometer or voltmeter: with an accuracy of not lower than ??? 0.5 mV, a sensitivity of not lower than ??? 0.2 mV and a measuring range of at least ??? 500 mV.
b) During the titration process, the instrument shall be able to display the potential value and pH value.
c) The instrument shall be protected against electrostatic fields. The surface exposed part of the glass electrode, the wire of the glass electrode, the titration standard, the potentiometer and the terminal of the potentiometer shall be grounded or separately shielded, so as to isolate the external electrostatic field.
d) Micro-burette: with a volume of 10 mL, a scale division of not greater than 0.01 mL and an accuracy of not lower than ??? 0.005 mL. The KOH standard solution is added directly to the titration vessel via the burette without exposure to the ambient air. The burette containing the KOH standard solution needs to be equipped with a dry tube to hold anhydrous sodium carbonate, soda lime or other substances that can absorb CO2. e) Titration cup: with a volume of 100 mL ~ 250 mL, made of borosilicate glass or other materials that will not react with organic heat transfer fluid.
f) Titration standard: on which, electrodes, stirrers and burettes, etc., can be reasonably placed.
g) Mechanical stirrer: magnetic or propeller stirring can be adopted. The stirring speed shall be such that the liquid is thoroughly stirred; if electric stirring equipment is used, it shall be properly used and grounded to prevent continuous changes in instrument readings when the motor is powered on or off during the titration process. A.2.2 Measurement electrode
A.2.2.1 The measurement electrode shall be a standard pH electrode suitable for non-aqueous titration.
A.2.2.2 Composite electrode. There is a silver / silver chloride (Ag/AgCl) reference electrode in the measurement electrode; the electrode filling solution is 1 mol/L ~ 3 mol/L lithium chloride - ethanol solution, which is convenient for operation and maintenance. Generally, the liquid junction part of the composite electrode shall have a movable protective sleeve to c (KOH)---the concentration of the KOH standard solution, expressed in (mol/L); V1---the volume of the KOH standard solution consumed when titrating potassium hydrogen phthalate, expressed in (mL);
V0---the volume of the KOH standard solution consumed in the blank test, expressed in (mL); m---the mass of potassium hydrogen phthalate, expressed in (g);
204.2---the molar mass of potassium hydrogen phthalate (KHC8H4O4), expressed in (g/mol). A.4.4 The range of the concentration of the KOH standard solution in parallel calibration shall be less than 0.0005 mol/L. In order to prevent the accuracy of the concentration of the KOH standard solution from being affected by CO2 in the air, the KOH standard solution shall frequently be re-calibrated (generally, at least once a month).
A.5 Electrode Potential
A.5.1 Testing of electrode potential
A.5.1.1 When a new electrode, a long-time electrode or a newly installed potentiometric titrator is used for the first time, the testing of electrode potential shall be performed. The electrodes in daily use shall also be regularly tested.
Method of testing: firstly, use a mixed solvent to clean the electrode, then, use water the clean the electrode and use a filter paper to dry it. Immerse the electrode into the pH 4 standard buffer solution, stir for 1 min, then, read the potential (mV) value; take out the electrode, respectively use water and pH 7 standard buffer solution to rinse it. Then, immerse it into the pH 7 standard buffer solution, stir for 1 min, then read the potential (mV) value, and calculate the difference between the two determined potential (mV) values. The minimum difference of a good electrode system is 162 mV (20 ???C ~ 25 ???C). If it is less than 162 mV, lift or rotate the protective sleeve of the liquid junction part to confirm that the filling solution can be freely discharged, then, fill the electrode with lithium chloride filling solution and re-perform the me...

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