GB/T 2013-2010 English PDF (GBT2013-2010)

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GB/T 2013-2010: Standard test method for density of liquid petrochemical products
GB/T 2013-2010
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 75.080
E 30
Replacing GB/T 2013-1980
Standard test method for density of liquid
petrochemical products
ISSUED ON: JANUARY 10, 2011
IMPLEMENTED ON: MAY 01, 2011
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of the PRC;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3 
Introduction ... 6 
1 Scope ... 7 
2 Normative references ... 8 
3 Terms and definitions ... 8 
4 Sampling ... 9 
5 Test method A - Hydrometer method ... 9 
6 Test method B - U-shaped vibrating tube method ... 15 
7 Test method C - Pycnometer method ... 21 
Appendix A (Normative) Table of water density ... 33 
Appendix B (Normative) Table of air density ... 35 
Appendix C (Informative) Density temperature factor of some liquid
petrochemical products ... 37 
Standard test method for density of liquid
petrochemical products
Warning: Use of this Standard may involve hazardous materials,
operations, and equipment, but this Standard is not intended to address
all safety issues associated with use. It is the responsibility of the user of
this Standard to, prior to operation, establish appropriate safety and
protective measures and determine the applicability of the relevant
regulations.
1 Scope
1.1 This Standard specifies three test methods for the determination of density
of liquid petrochemical products using hydrometer, U-shaped vibrating tube,
and pycnometer.
1.2 Test method A - Hydrometer method: This method is suitable for determining
the density of a flowable transparent liquid. For a viscous liquid which does not
flow easily, a constant-temperature bath can be used to measure the density
above room temperature. The method can also be used for density
measurement of opaque liquids; but the reading method is different from that of
transparent liquids.
1.3 Test method B - U-shaped vibrating tube method: This method is applicable
to petrochemical products which may be treated as single-phase liquids at test
temperature and test pressure. This method is applicable to any vapor-pressure
liquid; but appropriate measures shall be taken, to ensure that the sample is
always single-phase during treatment and measurement, with no loss of light
components and changes in composition and density.
1.4 Test method C - Pycnometer method: This method is applicable to the
density measurement of petrochemical products which may be treated as
liquids at the test temperature and test pressure. The capillary plug pycnometer
is not suitable for liquids with an initial boiling point below 40 °C. The graduated
double-capillary pycnometer is suitable for the accurate measurement of the
density of all liquid petrochemical products except for more viscous products,
especially for liquids with only a small amount of sample; but limited to liquids
with a kinematic viscosity not exceeding 50 mm2/s at the test temperature.
Note: The unit is kilograms per cubic meter (kg/m3) or grams per cubic centimeter (g/cm3).
3.4 Density temperature factor; γ
The change in liquid density for each change (rise or decrease) of temperature
of 1 °C.
Note: The unit is kg/(m3 • °C).
4 Sampling
SAMPLE according to the method specified in the product standard. When
there is no requirement in the product standard, samples are taken according
to the provisions of GB/T 4756 and GB/T 6680.
5 Test method A - Hydrometer method
5.1 Method summary
PLACE the sample at a specified temperature and pour it into a density
metering cylinder with approximately the same temperature. PLACE the
appropriate hydrometer into the temperature-adjusted sample and let it stand
still. When the temperature reaches equilibrium, read the hydrometer reading
and sample temperature and convert the density or standard density as needed.
If necessary, the density metering cylinder containing the sample can be placed
in a constant-temperature bath, to avoid excessive temperature fluctuations
during the measurement.
5.2 Sample preparation
5.2.1 Sample preparation
MIX the sample so that the loss of light components of the sample is minimized
and the sample integrity is maintained.
5.2.1.1 Volatile petrochemical products
To reduce light component losses, the sample shall be mixed in the original
container and the closed system.
Note: Mixing volatile samples in open containers will result in loss of light components and
will affect the measured density values.
5.4 Apparatus verification
5.4.1 The hydrometer shall be periodically verified using a standard hydrometer
traceable to national standards or the density of traceable reference materials
and re-verified at least once every five years.
5.4.2 The thermometer shall be periodically verified using a standard
thermometer traceable to national standards.
5.5 Apparatus preparation
5.5.1 CHECK the hydrometer’s reference point to determine if the hydrometer
scale is in the correct position in the main. If the scale has moved, it shall discard
the hydrometer.
5.5.2 The temperature of the density metering cylinder and hydrometer is
brought close to the sample temperature.
5.6 Test procedure
5.6.1 At the test temperature, transfer the sample to a temperature-stable and
clean density metering cylinder, to prevent the sample from splashing and
generating bubbles and to reduce the volatilization of light components.
5.6.2 USE a clean piece of filter paper to remove all bubbles formed on the
sample surface.
5.6.3 PLACE the cylinder containing the sample vertically in a place where there
is no air flow. Throughout the test, the ambient temperature change shall not
exceed 2 °C. When the ambient temperature changes by more than ±2 °C, a
constant-temperature bath shall be used, to avoid too much temperature
change.
5.6.4 USE a suitable thermometer or stir bar for vertical rotation to stir the
sample, to achieve uniform sample density and temperature throughout the
cylinder. RECORD the temperature to the nearest 0.1 °C. REMOVE the
thermometer or stir bar from the density metering cylinder.
5.6.5 PUT an appropriate hydrometer into the liquid; when reaching the
equilibrium position, let it go; LET the hydrometer float freely; TAKE care to
avoid wetting the main above the liquid level. PRESS the hydrometer 1 mm or
2 mm below the equilibrium point and return it to the equilibrium position, to
observe the meniscus shape. If the meniscus shape changes, it shall clean the
hydrometer main and repeat this operation, until the meniscus shape remains
the same.
Note 3: When the temperature of the sample tube of vibrating tube hydrometer is lower
than the dew point temperature of ambient air, moisture will condense on the
sample tube sensor and electronic components; the surrounding air shall be kept
dry.
6.2.2 Circulating constant-temperature bath: If a constant-temperature bath is
required, it shall be able to maintain the temperature of the circulating liquid
within ±0.05 °C of the required temperature.
6.2.3 Temperature sensor: After calibration, it shall be able to measure the
temperature of the sample tube, accurate to at least ±0.10 °C. The rate of
energy transfer through the sample tube is very low. Therefore, in order to
minimize heat transfer along the wire into and out of the sample tube, care shall
be taken to use a sensor with a very thin wire.
6.2.4 Homoge...