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Determination of Ignition Temperature of Coal
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Determination of ignition temperature of coal
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GB/T 18511-2017: PDF in English (GBT 18511-2017) GB/T 18511-2017
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 73.040
D 21
Replacing GB/T 18511-2001
Determination of Ignition Temperature of Coal
ISSUED ON: SEPTEMBER 7, 2017
IMPLEMENTED ON: APRIL 1, 2018
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 ... 4
4 Method Summary ... 4
5 Reagents ... 5
6 Instruments and Equipment ... 5
7 Coal Sample Processing ... 9
8 Test Procedures ... 10
9 Result Expression ... 11
10 Method Precision ... 11
11 Test Report ... 11
Determination of Ignition Temperature of Coal
1 Scope
This Standard specifies the terms and definitions, method summary, reagents,
instruments and equipment, coal sample processing, test procedures, result
expression, method precision and test report for the determination of ignition
temperature of coal.
This Standard is applicable to lignite, bituminous and anthracite.
2 Normative References
The following documents are indispensable to the application of this document. 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 483-2007 General Rules for Analytical and Testing Methods of Coal
3 Terms and Definitions
What is defined in GB/T 483-2007, and the following terms and definitions are
applicable to this document. For ease of use, some terms and definitions in GB/T 483-
2007 are repeatedly listed.
3.1 Ignition Temperature
Ignition temperature refers to the minimum combustion temperature, at which, coal
emits enough volatiles to form a combustible mixture with the surrounding atmosphere.
[GB/T 483-2007, Definition 3.2.35]
4 Method Summary
Place a processed coal sample into the initiation temperature determination device. At
a certain rate, heat it up. When it reaches a certain temperature, the coal sample
suddenly burns. Record the temperature, at which, the air volume in the determination
system suddenly expands or the heating rate suddenly increases as the ignition
temperature of the coal.
5 Reagents
Warning---since benzidine is a moderately toxic carcinogen, attempts shall be
made to minimize its long-term exposure to the air during the test. The operation
shall be carried out in a fume hood to avoid direct contact with the human body.
Unless it is otherwise stipulated, reagents confirmed to be analytically pure, and
distilled water or deionized water, or water of equivalent purity shall merely be used in
the analysis.
5.1 Sodium nitrite: before use, it shall be dried in a blast drying oven at 102 °C ~ 105 °C
for 1 h.
5.2 Benzidine.
5.3 Reducing agent: weigh-take 0.075 g of sodium nitrite and 0.0025 g of benzidine;
evenly mix them up. Prepare it before the test.
5.4 Hydrogen peroxide solution: mass fraction is 30%.
6 Instruments and Equipment
6.1 Ignition Temperature Determination Device
The device is shown in Figure 1. See the requirements for the various parts below:
a) Heating furnace: round; can be heated to 600 °C; temperature adjustable.
b) Heating body: made of copper or aluminum alloy; 7 holes; see Figure 2.
c) Temperature measurement and control instrument: can control the
temperature-rising rate from 4.5 °C/min to 5.0 °C/min within the range of
100 °C ~ 500 °C; temperature measurement accuracy is ± 1 °C.
d) Buffer ball (see Figure 3).
It can control the temperature at 102 °C ~ 105 °C.
6.6 Analytical Balance
Division value: 0.1 mg.
6.7 Glass Weighing Bottle
Diameter: 40 mm; height: 25 mm; with a tight grinding cover.
6.8 Agate Mortar
7 Coal Sample Processing
7.1 Raw Coal Sample
In the weighing bottle, weigh-take 0.5 g ~ 1.0 g of coal sample for general analysis and
test. Place it in a vacuum drying oven at the temperature of 55 °C ~ 60 °C and the
pressure of 53 kPa to dry for 2 h. Then, take it out and put it into a desiccator to cool
down to the room temperature. Before the test, weigh-take 0.09 g ~ 0.11 g of dried coal
sample and 0.075 g of sodium nitrite; gently grind them in an agate mortar for 1 min ~
2 min; evenly mix it up.
7.2 Oxidized Coal Sample
In the weighing bottle, weigh-take 0.5 g ~ 1.0 g of coal sample for general analysis and
test. Use a dropper to add drips of hydrogen peroxide solution (add around 0.5 mL per
gram of coal); use a glass rod to stir it. Cover it with a lid, then, place it in a dark place
for 24 h. Then, open the lid and expose to sunlight or incandescent lamp for 2 h; place
it in a vacuum drying oven at the temperature of 55 °C ~ 60 °C and the pressure of 53
kPa to dry for 2 h. Then, take it out and put it into a desiccator to cool down to the room
temperature. Before the test, weigh-take 0.09 g ~ 0.11 g of coal sample that goes
through the above-mentioned processing and 0.075 g of sodium nitrite; gently grind
them in an agate mortar for 1 min ~ 2 min; evenly mix it up.
7.3 Reduced Coal Sample
In the weighing bottle, weigh-take 0.5 g ~ 1.0 g of coal sample for general analysis and
test. Place it in a vacuum drying oven at the temperature of 55 °C ~ 60 °C and the
pressure of 53 kPa to dry for 2 h. Then, take it out and put it into a desiccator to cool
down to the room temperature. Before the test, weigh-take 0.09 g ~ 0.11 g of dried coal
sample and reducing agent (5.3); gently grind them in an agate mortar for 1 min ~ 2
min; evenly mix it up.
8 Test Procedures
8.1 Manual Determination
8.1.1 In accordance with Figure 1, connect the various parts of the device.
8.1.2 Put the heating body into the heating furnace that is lower than 100 °C.
8.1.3 Carefully transfer the processed coal sample to the sample tube; connect the
sample tube to the buffer ball. Then, put it into the heating body; insert the
thermocouple into the central hole of the heating body.
8.1.4 Reverse the tee of the water storage tube, so that the water storage tube is
connected to the atmosphere. Move the leveling bottle upwards to fill the water storage
tube with water. Then, move the leveling bottle downwards to let the water in the water
tank into the water measurement tube to a certain level. Immediately reverse the tee
of the water measurement tube, so that the water measurement tube is connected to
the buffer ball. If the water level of the water measurement tube stops after dropping
to a certain distance, it proves that the air tightness is good. Otherwise, it indicates that
there is air leakage, then, find out the cause and solve it.
8.1.5 Move the leveling bottle to fill the water measurement tube with water; maintain
the water level of the leveling bottle and the water level of the water storage tube in a
horizontal position. Turn off the tee of the water measurement tube.
8.1.6 Turn on the power of the heating furnace. Start to heat up; control the heating
rate to 4.5 °C/min ~ 5.0 °C/min. Wait till the temperature is raised to 100 °C, then,
record the temperature every 5 min. When it reaches 250 °C, rotate the tee of the water
measurement tube, so that the water measurement tube is connected with the buffer
ball. At any time, observe the water level of the water measurement tube. When it
suddenly drops, record the corresponding temperature.
8.1.7 After measuring the ignition temperature of each sample, cut off the power; take
out the thermocouple, sample tube and heating body.
8.2 Automatic Determination
8.2.1 Carefully transfer the processed coal sample to the sample tube. Place the
sample tube into the round hole around the heating body; place the heating body into
the heating furnace of the determination instrument.
8.2.2 Turn on the power. In accordance with the operation procedures in the instruction
manual, conduct the test.
8.2.3 After the test, take out the heating body and sample tube.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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