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Safety technology conditions for organic heat transfer fluid
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Standard ID | GB/T 24747-2023 (GB/T24747-2023) | Description (Translated English) | Safety technology conditions for organic heat transfer fluid | Sector / Industry | National Standard (Recommended) | Classification of Chinese Standard | J98 | Classification of International Standard | 27.060.30 | Word Count Estimation | 20,249 | Date of Issue | 2023-05-23 | Date of Implementation | 2023-05-23 | Older Standard (superseded by this standard) | GB/T 24747-2009 | Drafting Organization | China Boiler and Boiler Water Treatment Association, Ningbo Special Equipment Inspection and Research Institute, Dalian Boiler and Pressure Vessel Inspection and Testing Research Institute Co., Ltd., China Special Equipment Inspection and Research Institute, Suzhou Solutia Heat Transfer Oil Co., Ltd., Jiangsu Special Equipment Safety Supervision and Inspection Research Institute, Zibo Special Equipment Inspection and Research Institute, Shandong North Zite Special Oil Co., Ltd., Sinopec Petrochemical Research Institute, Jilin Hengsheng Chemical Co., Ltd., Hunan Special Equipment Inspection and Testing Research Institute, Chongqing Municipality Special Equipment Inspection and Research Institute, Jiangsu Zhongneng Chemical Technology Co., Ltd., Shanghai Jiuxing Heat Transfer Oil Co., Ltd., Hunan Deli Electronic Technology Co., Ltd., Tai'an Special Equipment Inspection and Research Institute | Administrative Organization | National Standardization Technical Committee of Boiler and Pressure Vessel (SAC/TC 262) | Proposing organization | National Standardization Technical Committee of Boiler and Pressure Vessel (SAC/TC 262) | Issuing agency(ies) | State Administration for Market Regulation, National Standardization Management Committee | Standard ID | GB 24747-2009 (GB24747-2009) | Description (Translated English) | [GB/T 24747-2009] Safety technology conditions for heat transfer fluids | Sector / Industry | National Standard | Classification of Chinese Standard | J98 | Classification of International Standard | 27.060.30 | Word Count Estimation | 17,135 | Date of Issue | 2009-10-30 | Date of Implementation | 2010-06-01 | Quoted Standard | GB/T 259; GB/T 261; GB/T 265; GB/T 268; GB/T 1884; GB/T 1885; GB/T 4756; GB/T 6536; GB/T 6682; GB/T 11133; GB/T 11137; GB/T 16483; GB/T 17144; GB/T 23800; GB/T 23971-2009; SH/T 0170; SH/T 0246; SH/T 0558; SH/T 0604 | Adopted Standard | DIN 51529, NEQ | Drafting Organization | China Association for boiler water treatment | Administrative Organization | National Standardization Technical Committee Boiler and Pressure Vessel | Regulation (derived from) | Announcement of Newly Approved National Standards No. 13 of 2009 (No. 153 overall) | Proposing organization | China boiler pressure vessel Standardization Technical Committee (SAC/TC 262) | Issuing agency(ies) | Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China; Standardization Administration of China | Summary | This Chinese standard specifies the types of organic heat carrier boiler and heat transfer system used by organic heat of terms and definitions, general requirements, quality indicators and test methods, determination and processing, inspection cycle and sampling, mixing, recycling, heat transfer system cleaning, replacement and disposal. This standard applies to a variety of organic heat carrier boiler for the heating equipment, and indirect heating for the purpose of organic heat carrier, does not apply to only a very low freezing and cooling for the purpose of organic heat carrier. |
GB/T 24747-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S 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’s 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 measurement.
If the difference is still less than 162 mV, clean or replace the electrode.
A.5.1.2 When two electrodes or three electrodes are used, the measurement electrode and
reference electrode shall be considered one. If one of the electrodes changes, then, the electrode
system also changes, and the testing shall be re-performed.
A.5.2 Correction of EP potential value
A.5.2.1 Regularly use the pH 11 0.02 standard buffer solution within the validity period to
correct the EP potential value of the electrode, so as to ensure that when there is no obvious
jump point on the titration curve, the endpoint can be correctly determined.
A.5.2.2 Immerse the electrode into the pH 11 0.02 standard buffer solution and stir for 5 min.
During the measurement, control the temperature change of the buffer solution within 2 C;
read the determined potential value, namely, the EP potential value, which can be used as the
titration endpoint of acid value when no jump point can be found on the titration curve during
the sample determination.
A.6 Determination of Acid Value
A.6.1 Preparation of standard solution
A.6.1.1 If the automatic potentiometric titrator is adopted, before the determination, the KOH
standard solution in the reagent bottle and the burette shall be circulated (discharge the air in
the burette and ensure that the burette is filled with the KOH standard solution), until the
concentration of the solution becomes uniform. If the manual potentiometric titrator is adopted,
evenly shake the KOH standard solution, then inject it into the burette.
A.6.1.2 Put the burette on the titration stand and make the port of the burette or the feed pipe
head slightly lower than the bottom of the electrode ball bubble. Record the initial reading of
the burette and the instrument reading.
A.6.2 Blank determination
During the determination of each batch of samples or after the mixed solvent is prepared, a
blank determination shall be conducted: take 60 mL of the mixed solvent to the titration cup,
put it on the titration stand and start the stirrer. In the case of automatic titration, in the mode of
equivalent titration of no more than 0.1 mL per drop, titrate to the endpoint; in the case of
manual titration, titrate with the amount of no more than 0.02 mL per drop, and after each drop,
wait until the potential stabilizes (the longest waiting time does not exceed 30 s) before adding
the next drop; titrate until the potential value displayed on the instrument reaches the EP
potential value, and record the volume of the KOH standard solution consumed by the blank.
A.6.3 Sample handling
A.6.3.1 If there is sediment in the organic heat transfer fluid, the sample shall be properly
handled: heat the sample with sediment to 60 C 5 C in the original sampling tank, and
vigorously stir it, so that the sediment is evenly suspended in the sample to be tested. If the
volume of the sample in the sampling tank exceeds three-quarters of the volume, the entire
sample shall be transferred to another clean glass bottle, and the volume of the glass bottle shall
exceed one-third of the entire sample volume; vigorously stir the sediment remaining in the
original sampling tank, then, transfer it to the glass bottle as well.
A.6.3.2 The organic heat transfer fluid may slightly change after being placed for a long time.
Hence, after sampling, it shall be determined as soon as possible; record the sampling and
determination time.
A.6.4 Weighing
At least two parallel tests shall be conducted for the sample determination. After the sample is
vigorously shaken (or handled), weigh an appropriate sample amount in the titration cup. It is
recommended to weigh in accordance with Table A.1.
Where,
S---the acid value (by KOH) of the organic heat transfer fluid, expressed in (mg/g).
V---the volume of the KOH standard solution consumed at the endpoint of the titration,
expressed in (mL). If there is a jump point, the endpoint is the volume consumed at the jump
point closest to the EP potential value; when the jump point is not obvious or absent, the
endpoint is the volume consumed when titrated to the EP potential value.
V0---the volume of the mixed solvent consumed by the blank, expressed in (mL).
c (KOH)---the actual concentration of the KOH standard solution, expressed in (mol/L).
56.1---the molar mass of KOH, expressed in (g/mol).
m---the sample mass, expressed in (g).
A.8 Precautions
A.8.1 Disposal of electrode
A.8.1.1 Before each use, the electrode shall be immersed in slightly acidic water for more than
5 min, then washed with water. Then, use the mixed solvent to clean it and carry out the
determination.
A.8.1.2 After the termination of each titration, use the mixed solvent to carefully clean the
electrode. If the next titration is to be performed, the electrode shall be immersed in water (if
necessary, in slightly acidic water) for at least 5 min, then, use the mixed solvent to clean the
electrode and start the titration of the next sample. For the potentiometric titrator equipped with
an autosampler, when determining the organic heat transfer fluid in use with a relatively high
viscosity, attention shall be paid to whether the electrode can be cleaned by automatic cleaning.
If necessary, the electrode shall be removed, and manually and carefully cleaned. If the
electrode is dirty, handle it in accordance with A.8.2.2.1.
A.8.1.3 When the electrode is not in use, it shall be immersed in the lithium chloride electrode
filling solution (the bulb shall be completely immersed). Between uses, the electrode can be
stored in slightly acidic water.
NOTE: if there is a long-time interval (more than 1 h) between two titrations, try not to immerse
the electrode in the mixed solvent.
A.8.2 Test and maintenance of electrode
A.8.2.1 Electrode responsiveness test
The electrode responsiveness checks the response speed and stability control test of the
electrode by continuously measuring the potential millivolt value. The method is as follows.
......
GB/T 24747-2009 (Renamed from GB 24747-2009)
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 27.060.30
J 98
GB 24747-2009
Safety Technology Conditions for Heat Transfer Fluids
ISSUED ON: OCTOBER 30, 2009
IMPLEMENTED ON: JUNE 01, 2010
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 5
4 General Requirements ... 8
5 Quality Index and Test Methods ... 9
6 Judgment and Disposal ... 10
7 Inspection Cycle and Sampling ... 12
8 Mixed Use ... 13
9 Recycling ... 14
10 Cleaning of the Heat Transfer System ... 14
11 Replacement and Disposal ... 14
Appendix A (Normative) Determination Method of Acid Value of Heat Transfer Fluids
(Potentiometric Titration Method) ... 16
Safety Technology Conditions for Heat Transfer Fluids
1 Scope
This Standard specifies the terms and definitions, general requirements, quality indicators and
test methods, determination and disposal, inspection cycle and sampling, mixing, recycling for
various types of heat transfer fluid boiler and its heat transfer system; as well as cleaning,
replacement and rejection of heat transfer systems.
This Standard is applicable to heat transfer fluids that use various heat transfer fluid boiler as
heating equipment for indirect heating, and is not applicable to heat transfer fluid that are only
used for freezing and low-temperature cooling.
2 Normative References
The provisions in following documents become the provisions of this Standard through
reference in this Standard. For dated references, the subsequent amendments (excluding
corrigendum) or revisions do not apply to this Standard, however, parties who reach an
agreement based on this Standard are encouraged to study if the latest versions of these
documents are applicable. For undated references, the latest edition of the referenced document
applies.
GB/T 259 Petroleum Products - Determination of Water-Soluble Acids and Alkalis
GB/T 261 Determination of Flash Point - Pensky-Martens Closed Cup Method (GB/T 261-
2008, ISO 2719:2002, MOD)
GB/T 265 Petroleum Products - Determination of Kinematic Viscosity and Calculation of
Dynamic Viscosity
GB/T 268 Petroleum Products – Determination of Carbon Residue - Conradson Method
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 6536 Petroleum Products - Determination of Distillation (GB/T 6536-1997, eqv
ASTM D86-95)
GB/T 6682 Water for Analytical Laboratory Use - Specification and Test Methods (GB/T
6682-2008, ISO 3696:1987, MOD)
GB/T 11133 Liquid Petroleum Products-Determination of Water-Karl Fischer Reagent
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 17144 Petroleum Products - Determination of Carbon Residue - Micro Method
(GB/T 17144-1997, eqv ISO 10370:1993)
GB/T 23800 Heat Transfer Fluids - Determination of Thermal Stability (GB/T 23800-2009,
DIN 51528:1998, MOD)
GB 23971-2009 Heat Transfer Fluids (DIN 51522:1998, MOD)
SH/T 0170 Petroleum Products - Determination of Carbon Residue (Electric Furnace
Process)
SH/T 0246 Determination Method for Water Content in Light Petroleum Products
(Coulometric Method)
SH/T 0558 Standard Test Method for Boiling Range Distribution of Petroleum Fractions
(Gas Chromatography)
SH/T 0604 Crude Petroleum and Petroleum Products-Determination of Density-
Oscillating U-Tube Method
3 Terms and Definitions
For the purposes of this Standard, the following terms and definitions apply.
3.1 Heat transfer fluids
The generic term for organic substances that are used as heat transfer media.
NOTE: Heat transfer fluids include all organic media that is used for indirect heat transfer purposes such
as heat transfer fluids, hot oils, organic heat transfer media, heating media, etc. According to chemical
composition, it can be classified into synthetic heat transfer fluids and mineral heat transfer fluids.
According to boiling range, it can be classified into vapor phase heat transfer fluids and liquid phase heat
transfer fluids.
3.2 Unused heat transfer fluids
Heat transfer fluids that have not been injected into the heat transfer system for use.
Under the operating conditions of the heat transfer system, the average main fluid temperature
of the heat transfer fluids measured at the boiler outlet is the working temperature; while the
maximum main fluid temperature of the heat transfer fluids allowed at the boiler outlet is the
maximum working temperature.
3.11 Maximum permitted film temperature
The liquid film temperature refers to the temperature in the boundary layer of the heat transfer
fluids in contact with the heating surface of the boiler; the maximum permitted film temperature
is the maximum permitted temperature where the heat transfer fluids contact the heating surface
of the boiler.
3.12 Calculated maximum film temperature
In the design of the heat transfer fluid boiler, the maximum film temperature of the boiler is
calculated according to the maximum design area heat flux density in the furnace and the design
heat exchange conditions of the heat transfer fluids in the furnace tube.
3.13 Initial boiling point (IBP)
The temperature point, using the petroleum fraction boiling range distribution method for
testing, and the accumulated area is equal to 0.5% of the total area of the obtained
chromatogram.
NOTE: The determination of the boiling range distribution of petroleum fractions adopts SH/T 0558.
3.14 Components with low boiling point
The substance that is distilled from the heat transfer fluids in use, with the temperature less than
the initial boiling point of the unused heat transfer fluids.
3.15 Bulk temperature at the inlet of boiler
The average main fluid temperature of the heat transfer fluids in use in the system return that is
measured at the boiler inlet.
3.16 Quality index
An index that is used to define the quality status of heat transfer fluids in use.
NOTE: According to its quality status, the quality index of the heat transfer fluids in use are divided into
permitted use quality index, safety warning quality index and stop-use quality index.
3.17 Closed heating system
The heat transfer system of heat transfer fluids in which the expansion tank is isolated from the
atmosphere.
NOTE: Closed systems usually use inert gas or cold oil liquid seals to isolate the expansion tank from
the atmosphere.
3.18 Opening heating system
The heat transfer system of heat transfer fluids in which the expansion tank communicates with
the atmosphere.
4 General Requirements
4.1 Heat transfer fluid products shall meet the requirements of GB 23971-2009. The heat
transfer fluid supplier shall provide the following product quality certification materials:
a) The type test report of the product issued by a testing agency and recognized by the
national competent authority.
b) The exit-factory quality inspection report of the batch of products issued by the
manufacturer. If a copy is provided by the supplier, the authenticity of the report shall be
confirmed by the supplier.
c) The safety data sheet for chemical products that meets the requirements of GB/T 16483.
4.2 For heat transfer fluid products with additives, in addition to meeting the requirements of
4.1, the type of added additives and relevant product information shall also be provided, as well
as the following certification materials issued by a testing agency and recognized by the
national competent authority:
a) Test report of thermal stability of heat transfer fluids before and after adding additives,
measured by the method of GB/T 23800;
b) Test report of thermal oxidation stability of heat transfer fluids before and after adding
additives, measured by the method in Appendix C of GB 23971-2009.
4.3 The maximum permitted bulk temperature of the heat transfer fluids shall be at least 10°C
higher than the maximum working temperature of the heat transfer fluid boiler, and its auto-
ignition point shall be no lower than the maximum permitted bulk temperature. For the case
where the design average area heat flux density of the coal-fired boiler or the radiant section of
the boiler is equal to or greater than 50kW/m2, the maximum permitted bulk temperature of the
heat transfer fluids shall be 20 °C higher than the maximum working temperature of the heat
transfer fluid boiler.
4.4 The maximum permitted film temperature of the heat transfer fluid is the temperature that
the heat transfer fluids in any part of the heat transfer system shall not exceed. The calculated
maximum film temperature of the heat transfer fluid boiler shall be no higher than the maximum
permitted film temperature of the heat transfer fluids.
4.5 L-QC and L-QD heat transfer fluid materials shall be used in closed circulation systems; L-
b) When the heat transfer fluids in use discharged from the system are re-injected into the
system;
c) After taking appropriate measures to improve the quality of the heat transfer fluids that
are confirmed to stop using, before intending to continue to be used;
d) Within 3 months after the system is replaced or mixed with different heat transfer fluid
products.
7.2 Sampling
7.2.1 Sampling of the unused heat transfer fluids shall meet the requirements of GB/T 4756;
and the sampling volume shall meet the requirements retained samples for verification
inspection and subsequent re-inspection; and the retained sample volume shall be no less than
2L.
7.2.2 The sampling of the heat transfer fluids in use shall be carried out through the sampling
cooler in the circulation loop of the system; the temperature of the taken sample shall be no
higher than 50 °C; and the taken sample shall be representative of the quality of the average
samples of the heat transfer fluids in use. The sampling volume shall meet the requirements of
the retained samples for inspection and re-inspection. The retention time of the re-inspection
samples shall be no less than 40 days.
8 Mixed Use
8.1 Vapor phase heat transfer fluids with different chemical compositions shall not be mixed;
and vapor phase heat transfer fluids and liquid phase heat transfer fluids shall not be mixed.
8.2 Generally, heat transfer fluids with different chemical and physical properties shall not be
added to the same system for mixed use.
8.3 If it is necessary to mix synthetic liquid phase heat transfer fluids with mineral heat transfer
fluids, or mix synthetic liquid phase heat transfer fluids of different chemical compositions, and
mix mineral heat transfer fluids produced by different manufacturers, the following
requirements shall be met:
a) It shall pass the thermal stability inspection of GB/T 23800, and have equivalent or higher
thermal stability than the original heat transfer fluids in use;
b) Meet the requirements of Clause 4 of this Standard;
c) The verification inspection specified in Table 1 shall be passed before adding;
d) The manufacturer or supplier shall ensure that the mixed heat transfer fluids can be used
safely.
8.4 The quantity and mixing ratio of the mixed heat transfer fluids added to the heat transfer
system shall be accurately recorded; meanwhile the mixed heat transfer fluids shall be sampled
and 2L of the reinspection sample shall be retained.
8.5 The mixed heat transfer fluids shall be used in accordance with the properties and
performance conditions of the original heat transfer fluids in use, and its quality index shall
meet the requirements of Table 2.
9 Recycling
9.1 For the heat transfer fluids in use that still has the value of recycling, distillation, filtration
and hydrofining can be used for recycling to remove the pollutants and part of the metamorphic
substances; so that the quality can be improved to a certain extent. After reaching the permitted
quality index, it can be returned to the original system to continue to use.
9.2 In the recycling process, acid-base neutralization shall not be used to reduce its acid value,
nor shall other chemical additives be added to change its physical properties.
10 Cleaning of the Heat Transfer System
10.1 When the heat transfer fluids in the system is seriously polluted, or an overheating and
overtemperature accident occurs in the boiler tube, and before the system replaces the heat
transfer fluids, the boiler and system shall be inspected. If coking has been produced or the
residual oil is seriously adhered, appropriate cleaning methods shall be used to remove the
pollutants in the system and the coke in the furnace tube to keep the system clean and avoid
pollution of the newly replaced heat transfer fluids.
10.2 Cleaning of the heat transfer fluids system shall not use cleaning media that pollute the
heat transfer fluids or cause corrosion hazards to system materials.
10.3 After the heat transfer fluids is injected into the cleaned system and exhausted and
dehydrated, it shall be sampled for inspection; and its quality shall meet the quality index
permitted to use in Table 2.
11 Replacement and Disposal
11.1 When the kinematic viscosity, acid value, carbon residue or pollution degree of the heat
transfer fluids in use is within the range of the "quality index stopped to use" in Table 2, and it
is difficult to effectively recycle it to the quality index permitted to use, all or partial heat
transfer fluids shall be replaced.
11.2 The replaced heat transfer fluids shall be disposed of in accordance with the laws and
regulations of the national safety and environmental protection department on the disposal of
Appendix A
(Normative)
Determination Method of Acid Value of Heat Transfer Fluids
(Potentiometric Titration Method)
A.1 Overview
A.1.1 This method is applicable to the determination of the acid value of heat transfer fluids.
The measurement range of the acid value is: 0 mg/g (by KOH) ~ 30 mg/g (by KOH).
A.1.2 This method uses potassium hydroxide (isopropanol) standard solution (hereinafter
referred to as KOH standard solution) as the titrant; dissolves the specimen with a mixed solvent
of toluene, isopropanol and a small amount of water; passes through the composite electrode or
a pair of glass indicator electrode-silver/silver chloride (Ag/AgCl) reference electrode for
potentiometric titration. The titration curve is drawn according to the consumption volume of
the KOH standard solution and potential value; and the end point is when the curve has an
obvious jump point (i.e., the stoichiometric point). Due to the existence of various weak acids
in the heat transfer fluids, there are often multiple jump points in the titration process; and the
endpoint judgment is based on the jump point corresponding to the potential value of the
standard buffer solution closest to pH 11±0.02 to calculate the acid value. If a jump point is not
found during the titration, the acid value is calculated by the volume of the standard solution
consumed when the electrode is titrated to the electrode in the pH 11±0.02 standard buffer
solution to obtain the potential value.
A.2 Instruments
A.2.1 Potentiometric titrator
A.2.1.1 Automatic potentiometric titrator
Basic requirements of automatic potentiometric titrator are as follows:
a) The automatic titration system shall be able to meet the setting requirements in A.5.7;
b) Motor-driven burette: the accuracy is no less than ±0.001mL;
c) The titrant addition method shall be able to carry out the dynamic addition mode, that is,
during the titration process, the addition volume and rate of the titrant shall be able to
change with the change of the potential;
d) The measurement method is "balance control mode", and the potentiometric titration
curve and the first-order differential curve shall be drawn simultaneously during the
automatic titration process;
e) The reagent bottle containing the KOH standard solution shall be provided with a drying
tube that can absorb CO2 (such as a drying tube containing soda, soda lime, etc.);
f) Mechanical stirrer: program control shall be adopted; and propeller stirrer or magnetic
stirrer can be used. The stirring speed shall be able to fully stir the liquid (a vortex is
generated, but the liquid shall not be splashed or the air shall be stirred into the solution);
g) Titration cup, 100mL volume; made of borosilicate glass or other materials that shall not
interact with the heat transfer fluids.
A.2.1.2 Manual potentiometric titrator
Basic requirements of manual potentiometric titrator are as follows:
a) Potentiometer or voltmeter: electrodes comply with the provisions of A.2.2; when the
resistance between the two electrodes is between 0.2 MΩ and 20 MΩ, the accuracy of
the potentiometer or voltmeter is ±0.5mV, the sensitivity is ±0.2mV, and the range is at
least ±500mV.
b) The instrument shall be able to display the potential value or pH value.
c) The instrument must be protected against electrostatic fields. The exposed surface of the
glass electrode, the wire of the glass electrode, the titration table, the potentiometer, and
the terminals of the potentiometer shall be grounded or shielded separately to isolate the
external electrostatic field.
d) Micro-burette: the subscale is no more than 0.01mL; the accuracy is no less than
±0.005mL. KOH standard solutions are added directly to the titration vessel through the
burette without exposure to ambient air. Burettes containing KOH need to have drying
tubes containing soda, soda lime or other substances that can absorb CO2.
e) The titration vessel, with a volume of 100mL ~ 250mL, is made of borosilicate glass or
other materials that shall not interact with heat transfer fluids.
f) The titration table can reasonably place electrodes, stirrers and burettes.
g) Mechanical stirrer: magnetic stirrer or propeller stirrer can be used. The stirring speed
shall be sufficient to stir the liquid (a vortex is generated, but no liquid shall be splashed
or air shall be stirred into the solution). If an electric stirring device is used, it needs to
be properly used and grounded to prevent persistent changes in meter readings when the
motor is powered on or off during titration.
A.2.2 Measuring electrodes
A.2.2.1 The measuring electrode shall use a standard pH electrode suitable for non-aqueous
titration.
A.2.2.2 Composite electrode. There is an Ag/AgCl reference electrode in the measuring
standard solution, the standard solution shall be calibrated frequently (generally at least once a
month).
Warning: Reagents such as isopropyl alcohol and toluene are toxic substances, and shall
be strictly prevented from entering into mouth or splashing on the skin and eyes. The
solution preparation and measurement process shall be carried out in a fume hood; and
protective glasses, latex gloves, gas masks, etc. shall be worn.
A.4 Electrode system
A.4.1 Electrode preparation
A.4.1.1 The Ag/AgCl reference electrode used in titration shall use the lithium chloride
electrode filling liquid, otherwise it needs to be replaced. The method is as follows: emptying
the original electrolyte in the electrode; cleaning by the lithium chloride electrode filling liquid
for several times; and finally filled with the lithium chloride electrode filling liquid. The
composite electrode is also treated in the same way.
A.4.1.2 Detection of electrode potential: when a new electrode, an electrode that are unused for
a long time or a newly installed potentiometric titrator is used for the first time, the electrode
potential shall be detected; and then it shall be detected regularly.
Detection method: first clean the electrode by mixed solvent; then clean by the Class-II water;
and then dry the water droplets on the electrode with filter paper. Immerse the electrode in pH
4±0.02 standard buffer solution; stir for 1min, and read the potential value (mV). Take out the
electrode and use Class-II water and pH 7 buffer solution to resin; then immerse in pH 7±0.02
standard buffer solution; stir for 1min, read the number of potential mV; and calculate the
potential difference between two measurements. A good electrode system has a minimum
difference of 158mV (20°C ~ 25°C). If it is less than 158mV, open the protective cover of the
electrode liquid junction; confirm that the electrode filling liquid can flow out freely; and re-
measure. If it is still less than 158mV, clean or replace the electrode.
A.4.1.3 When double or triple electrodes are used, the measuring electrode and the reference
electrode shall be considered as one. If one of the electrodes is changed, the electrode system
has also changed and needs to be retested.
A.4.1.4 Before each use, the electrode shall be soaked in slightly acidic water for more than 5
min; then washed by Class-II water; and then washed by mixed solvent for measurement.
A.4.1.5 When the electrode is not in use, the electrode shall be immersed in the lithium chloride
electrode filling liquid (the bulb shall be completely immersed). When in use, the electrode can
be stored in slightly acidic water with a pH of 4.5 ~ 5.5. Note: If there is a long-time interval
(more than 1h) between two titrations, try not to immerse the electrode in the mixed solvent.
A.4.2 Correction of EP potential value
A.4.2.1 Regularly calibrate the electrode with fresh pH 11±0.02 standard buffer solution to
b) If no jump point is found in the titration process, calculate the acid value by the volume
of the standard solution consumed when titrating to the EP potential value.
A.5.6.2.2 Setting of titration volume of KOH standard solution during titration:
a) Determination of new oil: the maximum titration volume is 0.01mL; the minimum
titration volume is no more than 0.001mL (or the maximum addition rate is 0.1mL/min;
the minimum is 0.01mL/min); the stop titration volume is 10mL;
b) Determination of old oil: the maximum titration volume is 0.1mL; the minimum titration
volume is no more than 0.005mL (or the maximum addition rate is 0.5mL/min; the
minimum is 0.05mL/min); the stop titration volume is 20mL.
A.5.6.3 During the titration process, the KOH standard solution adopts the dynamic addition
mode or the equivalent titration mode; and the range of the potential change after each
increment shall be controlled within 5mV ~ 15mV. If the potential changes less than 5mV
within 10s, add the next drop, the longest waiting time is 60s.
A.5.6.4 When the potential exceeds the EP potential value by more than 60mV, stop the titration.
If there is a peak in the first derivative that exceeds the largest peak generated by electrostatic
noise, it is identified as a jump point. The measurement result of acid value shall be displayed
directly after measurement by automatic titrator.
A.5.6.5 After the titration is completed, use the mixed solvent to carefully clean the electrode.
Especially for potentiometric titrators equipped with an automatic sampler, when measuring
old oils with high viscosity, it may be difficult to clean the electrodes by automatic cleaning
alone. If necessary, the electrodes shall be removed and carefully cleaned manually.
A.5.7 Manual titration method
A.5.7.1 Add KOH standard solution dropwise at a suitable speed; after the potential is stable
by reaction, record the titration volume of the standard solution; and read the potential value at
this time.
A.5.7.2 The titration process shall be controlled according to the following requirements:
a) Determination of new oil:
1) In order to obtain better accuracy, the concentration of KOH standard solution shall be
0.02 mol/L or less. The manual burette (minimum division 0.01 mL) shall be replaced
by automatic burette (minimum division 0.001 mL) to obtain a smaller addition amount
of KOH standard solution;
2) During the titration, if the potential change is less than 10mV for every 0.05mL increase
of the KOH standard solution, the titration amount shall be appropriately increased each
time; so that the resulting potential change is about 10mV. If the potential change is
greater than 10mV for every 0.05mL increase of the KOH standard solution, the
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