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GB/T 8019-2008 PDF in English


GB/T 8019-2008 (GB/T8019-2008, GBT 8019-2008, GBT8019-2008)
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GB/T 8019-2008: PDF in English (GBT 8019-2008)

GB/T 8019-2008
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 75.160.20
E 31
Replacing GB/T 8019-1987
Standard test method for gum content in fuels by jet
evaporation
ISSUED ON: AUGUST 25, 2008
IMPLEMENTED ON: FEBRUARY 01, 2009
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 ... 5
2 Normative references ... 5
3 Terms and definitions ... 6
4 Method summary ... 6
5 Significance and use ... 6
6 Apparatuses ... 7
7 Materials and reagents ... 8
8 Sampling ... 8
9 Preparation ... 8
10 Calibration and standardization ... 9
11 Test procedure... 11
12 Calculation ... 13
13 Report ... 14
14 Precision and deviation ... 14
15 Keywords ... 16
Standard test method for gum content in fuels by jet
evaporation
1 Scope
1.1 This Standard specifies the test method for gum content in existent gum of
aviation fuels, and motor gasoline and other volatile fractions (including
products that contain alcohol, ether oxygen-compounds and sediment inhibitor
additives) during the test.
1.2 This Standard specifies the determination method for the insoluble part of
n-heptane in non-aviation fuel residues.
1.3 This Standard adopts the units of International System of Units (SI).
1.4 This Standard involves certain hazardous materials, operations and
equipment, but it does not intend to make recommendations on all related
safety issues. Therefore, it is necessary for users to establish appropriate safety
and protection measures and determine an applicable management system
before using this Standard. For special warning statements, see 6.4, 7.2 and
8.2.1 for details.
2 Normative references
The terms in the following documents become the terms of this Standard by
reference to this Standard. For dated references, all subsequent amendments
(not including errata content) or revisions do not apply to this standard. However,
parties to agreements that are based on this Standard are encouraged to study
whether the latest versions of these documents can be used. For undated
references, the latest edition applies to this Standard.
GB/T 514, Specification for liquid-in-glass thermometers for testing of
petroleum products
GB/T 4756, Method for manual sampling of petroleum liquids (GB/T 4756-
1998, eqv ISO 3170:1988)
GB/T 8170, Rules of rounding off of numerical values
oils or particulate matters, which usually reflects improper handling in the
downstream transmission and distribution process of the refinery.
6 Apparatuses
6.1 Balance: the sensitivity is 0.1 mg.
6.2 Beaker: 100 mL in capacity. Its size is shown in Figure 1.
Group the beakers. The number of each group is determined by the number of
beaker holes in the evaporation bath. Mark each beaker in each group with a
number or letter, including the tared beaker.
6.3 Cooling container: desiccator or other containers that can be tightly closed.
It is used to cool the beaker before weighing, and it’s unnecessary to use
desiccant.
Note: The use of desiccant will cause incorrect results.
6.4 A solid metal block bath or a liquid bath can be used for electrical heating.
It is composed according to the principle that is shown in Figure 1. The bath
shall have two or more beaker holes and exhaust ports. When it is equipped
with a conical adapter that is made of 500 μm ~ 600 μm copper or stainless-
steel sieve, the flow rate of each exhaust port shall be 1 000 (mL/s) ± 150 (mL/s).
If a liquid bath is used, it shall contain a suitable liquid within 25 mm from the
top. A temperature controller or appropriate liquid reflux can be used to maintain
the temperature.
Warning -- If an evaporation bath that is filled with liquid is used, make
sure that the flash point of the used liquid is at least 30 °C higher than the
expected maximum bath temperature.
6.5 Flowmeter: As shown in Figure 1, it can measure a flow rate of air or steam
at each exhaust port of 1 000 mL/s. Alternatively, a pressure gauge can be used
to measure a flow rate of air or steam at each exhaust port of 1 000 (mL/s) ±
150 (mL/s).
6.6 Sintered glass funnel: coarse hole, 150 mL in capacity.
6.7 Steam: A suitable method can be used to generate the required amount of
steam of 232 °C ~ 246 °C at the air inlet of the evaporation bath.
6.8 Thermometer: It shall meet the technical requirements of the thermometer
No. GB-29 in GB/T 514.
6.9 Graduated cylinder: 50 mL ± 0.5 mL in capacity.
6.10 Transferring tool: Brazier-head stainless-steel tweezers or stainless-steel
pliers, which are used to take out the beaker and the conical adapter.
7 Materials and reagents
7.1 Air: Filtered air whose pressure is not greater than 35 kPa.
7.2 Steam: Without oily residue; the pressure is not less than 35 kPa.
Warning -- If a steam heater is used, use protective equipment as required
to avoid contact with exposed skin.
7.3 N-heptane: analytical reagent.
7.4 Gum solvent: A mixture of equal volume of toluene and acetone.
8 Sampling
The sampling method is specified in GB/T 4756; the taken samples shall be
representative.
9 Preparation
9.1 Assembly of air jet apparatus
9.1.1 Assemble the air jet apparatus as shown in Figure 1. Adjust the air flow
rate at the outlet of the test device to 600 (mL/s) ± 90 (mL/s) at room
temperature. Check whether the air flow rates at the remaining outlets are
consistent.
Note: The reading of each outlet at normal temperature and pressure of 600
(mL/s) ± 90 (mL/s) will ensure that the output is 1 000 mL/s ± 150 mL/s
at a temperature of 155 °C ± 5°C.
9.1.2 Heat the evaporation bath (see 6.4), until the temperature of the bath
reaches 160 °C ~ 165 °C; introduce air into the apparatus, until the flow rate of
each outlet reaches the flow rate that is required in 9.1. Use a thermometer (see
6.8) to measure the temperature of each hole. The temperature-sensitive
bubble of the thermometer shall be inserted into the bottom of the beaker in the
hole. This method does not apply to any hole whose temperature exceeds the
range of 150 °C ~ 160 °C.
in millimeters
10.1.2 A method to calibrate the air flow is to separate the calibrated flowmeter
from the apparatus that is described in 6.5, and directly detect the flow of each
outlet under normal temperature and pressure. To ensure the accuracy of the
data, the back pressure of the flowmeter shall be less than 1 kPa.
10.1.3 Alternatively, another method of calibrating air flow is to measure and
adjust the corresponding total air flow that is supplied to all outlets. The total air
flow is equal to the air flow of each outlet multiplied by the number of outlets
(for example, if the apparatus has 5 holes, and the measured total flow is 3 000
mL/s, that is, the flow of each hole is 600 mL/s). When the total flow rate that is
supplied to all outlets reaches an appropriate value after testing, compare the
relative flow rate of each hole, to check whether it is consistent and meets the
requirements in 10.1.1.
10.2 Steam flow correction
10.2.1 Check or calibrate the steam flow to ensure that all outlets reach 1 000
(mL/s) ± 150 (mL/s) under normal temperature and pressure. Refer to the
manual of the apparatus to complete the steam flow calibration process.
10.2.2 A method to calibrate the steam flow is to connect a copper tube to the
steam outlet and extend the copper tube into a mass-weighed 2 L graduated
cylinder that contains crushed ice. Let the steam be discharged into the
graduated cylinder for about 60 seconds. Adjust the position of the graduated
cylinder, so that the end of the copper tube is immersed in water for less than
50 mm, to prevent excessive back pressure. After a reasonable period of time,
remove the copper tube from the graduated cylinder and weigh the mass of the
cylinder. The increased mass represents the amount of condensed steam.
Calculate the steam flow rate according to Formula (1):
Where:
R -- steam flow, in milliliters per second (mL/s);
m1 -- mass of the graduated cylinder that contains the condensed steam, in
grams (g);
m2 -- mass of ice and the graduated cylinder, in grams (g);
mk -- mass of 1 000 mL of steam at 232 °C under normal pressure; its value is
0.434 g;
t -- condensation time, in seconds (s).
11.5 Use a graduated cylinder to weigh 50 mL ± 0.5 mL of the sample; pour it
into each weighed beaker (except the tared beaker). Use a beaker for each to-
be-tested fuel. Put the beaker that contains the sample and the tared beaker
into the evaporation bath; the time between the first beaker and the last beaker
shall be as short as possible. When using air to evaporate the sample, stainless
steel tweezers or pliers shall be used, to place the conical adapter. When using
steam to evaporate, it’s allowed to heat the beaker for 3 min ~ 4 min before
using stainless steel tweezers or pliers to place the conical adapter. Use steam
to preheat before the conical adapter is connected to the outlet. Place the
conical adapter in the center of the top of the hot steam bath; begin to introduce
air or steam to reach the specified flow rate; maintain the specified temperature
and flow rate; let the sample evaporate for 30 min ± 0.5 min.
Note: When introducing air or steam, be careful and avoid splashing. Splashing
may make the gum determination result too low.
11.6 At the end of heating, use stainless steel tweezers or pliers to remove the
conical adapter; transfer the beaker from the bath to the cooler; place the
cooling container near the balance for at least 2 hours. Weigh each beaker as
described in 11.3 and record its mass.
11.7 The beaker that contains the residue of motor gasoline shall be tested
according to the steps that are described in 11.8 ~ 11.12; the remaining beakers
can be taken back for cleaning for reuse.
If a retained sample of the original finished gasoline is used for the reference
test, the qualitative evidence of the contamination of motor gasoline can be
obtained by weighing the residue. This reference test is important, because
motor gasoline contains artificially added non-volatile substances. To prove the
contamination, further research is required.
11.8 For non-aviation fuels whose unwashed gum content is less than 0.5
mg/100mL, it's unnecessary to perform this part of the washing step, nor to
follow the steps of 11.9 ~ 11.12, because the solvent washed gum content is
always less than or equal to the unwashed gum content. If the unwashed gum
content is not less than 0.5 mg/100mL, add 25 mL of n-heptane to each beaker
that contains the residue and rotate it gently for 30 s; let the mixture stand for
10 min. Process the tared beaker in the same way.
11.9 Pour out the n-heptane solution carefully, to prevent any loss of solid
residue.
11.10 Use the second 25 mL n-heptane; extract again according to the steps
that are described in 11.8 and 11.9. If the extract is colored, perform the third
extraction again. Do not extract more than 3 times.
Z -- mass of the tared beaker that is recorded in 11.12, in grams (g);
13 Report
13.1 For results, of which the existent gum content of aviation fuel is greater
than or equal to 1 mg/100mL, report the existent gum content result, and round
off the value according to GB/T 8170, to the accuracy of 1 mg/100mL; for the
results less than 1 mg/100mL, report the existent gum content as "< 1
mg/100mL".
13.2 For results, of which the non-aviation fuel solvent washed gum or
unwashed gum content is greater than or equal to 0.5 mg/100mL, report the
solvent washed gum or unwashed gum content results, and round off the value
according to GB/T 8170, to the nearest 0.5 mg/100mL; for results less than 0.5
mg/100mL, report as "< 0.5 mg/100mL". If the unwashed gum content is less
than 0.5 mg/100mL, report the solvent washed gum content as "< 0.5 mg/100mL”
as well.
13.3 For all samples, if a filtration step (see 11.4) is carried out before
evaporation, indicate the words "after filtration" after the value of the gum
content result.
14 Precision and deviation
14.1 Precision
See 14.1.1 and 14.1.2, as well as the curve in Figure 2, for the precision that is
obtained from the statistical test results between laboratories (95% of
confidence level).
Note: The precision of solvent washed gum content and unwashed gum content
that is given in this method is statistically researched and measured
between laboratories in 1997 with refined motor gasoline (including
products that contain alcohol and ether oxygen-compounds and
sediment inhibitor additives); the precisions of solvent washed gum
content and unwashed gum content are respectively based on samples
that contain 0 ~ 15 mg/100mL and 0 ~ 50 mg/100mL of gum content.
14.1.1 Repeatability (r): The difference between the results of two tests that are
performed on the same sample by the same operator using the same
instrument under the same operating conditions. For aviation gasoline, the
existent gum content shall not exceed the value that is specified by Formula (5);
for jet fuel, the existent gum content shall not exceed the value that is specified
by Formula (6); for motor gasoline, the unwashed gum content shall not exceed
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.