SH/T 0680-1999 English PDF (SHT0680-1999)

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SH/T 0680-1999: Heat transfer fluids - Determination of thermal stability
SH/T 0680-1999
SH
INDUSTRY STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 75.100
Heat transfer fluids –
Determination of thermal stability
ISSUED ON. SEPTEMBER 1, 1999
IMPLEMENTED ON. APRIL 1, 2000
Issued by. State Petroleum and Chemical Industry
Table of Contents
Foreword ... 3 
1  Scope ... 4 
2  Normative references ... 4 
3  Terms ... 4 
4  Method summary ... 5 
5  Significance and purpose ... 5 
6  Instruments and materials ... 5 
7  Reagents ... 6 
8  Test steps ... 6 
9  Calculation ... 7 
10 Report ... 10 
Foreword
This Standard equivalently adopts German national standard DIN 51528-1994 Determination
Method of Liquid Heat Stability of Heat Carrier. The main difference between this Standard and
DIN 51528-1994 include.
(1) Add the requirements for weighing accuracy of specimen and instrument.
(2) Add the report about appearance of specimen after heating.
(3) The minimum volume of borosilicate glass ampoule is increased to 15 mL from 5 mL.
This Standard was proposed by China Petroleum and Chemical Corporation.
This Standard shall be under jurisdiction of Academy of Science of Petroleum and Chemical of
China Petroleum and Chemical Corporation.
Drafting organizations of this Standard. Academy of Science of Petroleum and Chemical of China
Petroleum and Chemical Corporation.
Main drafters of this Standard. Wang Fei, and Liang Hong.
Determination method of thermal stability of heat transfer
fluids
1 Scope
This Standard specifies the test method of thermal stability of heat transfer fluids of mineral oil and
synthetic hydrocarbon type.
This Standard is applicable to the heat transfer fluids used in the open system (the maximum
operating temperature under normal pressure is less than its initial boiling point or boiling point) or
closed system (the maximum operating temperature is more than its initial boiling point or boiling
point).
2 Normative references
The articles included in the following standard have become part of this Standard by reference.
Unless otherwise expressly provided in this Standard, the following references shall be the current
effective standards.
SH/T 0558 Petroleum distillate boiling range distribution determination method (gas
chromatographic method)
3 Terms
This Standard uses the following terms.
3.1 Thermal stability
In the test temperature and test process, the stability that the heat transfer fluid reacts to heating.
Note. Along the rise of temperature, the changes of heat transfer fluid are accelerating, and
generate the gas phase decomposition products, products of lower boiling point, products of higher
boiling point as well as products which can not be evaporated. The type and quantity of products
will affect the use performance of heat transfer fluid.
In order to assess the thermal stability, it needs to determine the content of the generated gas
phase decomposed products, products of lower boiling point, products of higher boiling point as
well as products which can not be evaporated from heat transfer fluid after heating; and the sum of
these products’ percentage content is expressed in deterioration rate. The smaller the
deterioration rate, the better the product thermal stability.
3.2 Gaseous decomposition products
After heating the sample, the substances of which the boiling point is less than room temperature
under the normal pressure, such as hydrogen and methane, etc.
3.3 Products of lower boiling point
After heating the sample, the substances of which the boiling point is less than the initial boiling
point of the heat transfer liquid which is not used.
borosilicate glass ampoule; make the gas evaporated completely; then weigh the mass (m4) of
borosilicate glass ampoule, accurate to 0.1mg.
Note. The large borosilicate glass ampoule or specimen that is loaded with high hot-load shall be equipped with the
safety protection cover during cooling process. When weighing it, include all glass fragments; remove the adhering
condensation water.
8.6.2 Open the stainless steel test device
Put the borosilicate glass ampoule in the Dewar flask; under the condition of frozen acetone or
isopropanol and dry ice (about -70°C), reduce the internal pressure. After 5~10min, open the
borosilicate glass ampoule; make the gas evaporated completely; then weigh the mass (m4) of
borosilicate glass ampoule, accurate to 0.1mg.
Note. Remove the adhering condensation water when weighing.
8.7 Use SH/T0558 method to determine the range of boiling point of specimen before and after
heating.
8.8 Determination of content of unevaporated products
8.8.1 Weigh the mass (m5) of empty tail ball in the bulb tube distiller, accurate to 0.1mg; then dip 4g
of heating specimen in the tail ball; weigh this mass (m6), accurate to 0.1mg.
8.8.2 Use vacuum pump to pump to vacuum, so as to make the pressure in the bulb tube reach
10Pa ± 0.2Pa finally. Rotate the bulb tube in the bulb tube distiller; heat it to 250°C ± 1°C slowly;
maintain this test temperature and pressure until the evaporable part in the unevaporated products
is less than 0.1 % of specimen mass (m/m).
8.8.3 Weigh the mass of tail ball after test (m7), accurate to 0.1mg.
9 Calculation
9.1 Calculation of content of specimen of gaseous decomposition products
The calculation of gaseous decomposition products of specimen G[%(m/m)] is by formula (1).
100)/()( 12`43  mmmmG ... (1)
Where.
m1 — mass of empty test device, g;
m2 — mass of test device equipped with specimen which is not heating, g;
m3 – mass of sealed test device, g;
m4 – mass of test device after opening, g.
Note. The gaseous decomposition products of specimen below 0.5%(m/m) is negligible.
9.2 Calculation of content of specimen unevaporated products
The content of specimen unevaporated products U[%(m/m)] is calculated by formula (2).
10 Report
10.1 Type of heat transfer liquid;
10.2 Test time, h;
10.3 Test temperature, °C;
10.4 Deterioration rate, take the average value of three test results, %(m/m), accurate to one digit
after decimal point;
10.5 Content of gaseous decomposition products and products of lower boiling point, %(m/m),
accurate to one digit after decimal point;
10.6 The content of products of higher boiling point and unevaporated products, %(m/m), accurate
to one digit after decimal point;
10.7 Initial boiling point and final boiling point of specimen before and after heating, °C;
10,8 Appearance of heating specimen;
10.9 Conditions which are not consistent with this Standard;
10.10 Test date.