GB/T 4632-2008 English PDF (GB/T4632-2008)

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GB/T 4632-2008: Determination of moisture-holding capacity of coal
GB/T 4632-2008
GB
NATIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 73.040
D 21
Replacing GB 4632-1997
Determination of moisture-holding capacity of coal
(ISO 1018.1975, Hard coal –
Determination of moisture-holding capacity, MOD)
ISSUED ON. SEPTEMBER 18, 2008
IMPLEMENTED ON. APRIL 01, 2009
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of PRC.
Table of contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Method summary ... 4 
4 Reagents and materials ... 5 
5 Instruments and apparatuses ... 5 
6 Coal sample collection and preparation ... 8 
7 Measurement step ... 8 
9 Method precision ... 10 
10 Test report ... 10 
Appendix A (Informative) Comparison between clause number of this standard
and clause number of ISO 1018.1975 ... 12 
Appendix B (Informative) Technical difference and causes between this standard
and ISO 1018.1975 ... 13 
Foreword
This standard, through revising, ADOPT the international standard ISO 1018.
1975 "Hard coal - Determination of moisture-holding capacity" (in English).
This standard is re-drafted based on ISO 1018. 1975. Taking into account of
China's national conditions, when using ISO 1018.1975, some modifications
are made in this standard. The relevant technical differences had been
incorporated into the main text, and meanwhile a single vertical line is used at
the margin adjacent to the relevant clauses to identify such differences. In
Appendix A, it provides the comparison list between the clause numbers of this
standard and the clause numbers of ISO 1018.1975; In Appendix B, it provides
these technical differences and their causes.
This standard replaces GB 4632-1997 "Determination of moisture-holding
capacity of coal". As compared with GB 4632-1997, the main changes of this
standard are as follows.
- In the “Normative references”, ADD the GB/T 483 (Chapter 2 of this version);
- In the “Method summary”, HIGHLIGHT the concept of “nitrogen charging
normal pressure” (Chapter 3 of this version);
- ADD the chapter of “Test reports” (Chapter 10 of this version).
The Appendix A and Appendix B of this standard are informative appendixes.
The standard was proposed by China Coal Industry Association.
This standard shall be under the jurisdiction of the National Standardization
Technical Committee of Coal.
This drafting organization of this standard. CCRI Coal Analysis Laboratory,
Inner Mongolia Coal Geology Institute.
The main drafters of this standard. Deng Xiumin, Wang Runye.
This standard replaces the standards previously issued as follows.
- GB 4632-1984, GB 4632-1997.
Determination of the maximum inherent
moisture of coal
1 Scope
This standard specifies the method summary, reagents and materials,
instruments and equipment, coal sample collection and preparation,
measurement steps, result calculation, and method precision of using nitrogen
charging normal pressure method to measure the maximum inherent moisture
of coal.
This standard applies to lignite, bituminous coal and anthracite.
2 Normative references
The provisions in following documents become the provisions of this standard
through reference in this standard. For the dated references, the subsequent
amendments (excluding corrections) 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 212 Proximate analysis of coal (GB/T 212-2008, ISO 11722.1999, ISO
1171.1997, ISO 562.1998, NEQ)
GB 474 Method for preparation of coal sample (GB 474-2008, ISO
18283.2006, Hard coal and coke - Manual sampling, MOD)
GB/T 483 General rules for analytical and testing methods of coal
GB/T 6003.1 Test sieves of metal wire cloth
GB/T 16496 Chemical reagent – Potassium sulfate
3 Method summary
After the coal sample is saturated with water, USE permanent wet paper to
remove most of external water; at the temperature of 30°C, relative humidity
96%, AND nitrogen charging normal pressure, MAKE it reach to humidity
balance; then MAKE it subject to drying in the nitrogen stream at the
1 - Water tank shell;
2 - Humidifier wall, which is made of copper panel;
3 - Double lid, through which circulating water can be pumped in;
4 - Propeller, angle of 15 ° ~ 20 °;
5 – Potassium sulfate crystallization and its saturated solution;
6 - Weighing bottle;
7 – Plug-shaped gas circulator, made of brass;
8 - Screw clamps;
9 - Rubber gasket;
10 - Heater;
11 - Temperature controller, which is composed of mercury contact
thermometer, transistor relay, AND solenoid valve;
12 - Thermometer, indexing is 0.1°C;
13 - Weighing bottle positioning pin;
14 – Foam plastic;
15 - Weighing bottle holder;
16, 17 - Nitrogen inlet and outlet.
Figure 1 Nitrogen charging normal pressure method maximum
inherent moisture meter
5.3 Nitrogen oven. it is allowed to choose any one type from the following two
types.
5.3.1 Small space nitrogen oven. the oven is tight, having relatively smaller free
space; it has nitrogen inlet and outlet as well as automatic temperature control
device, which can maintain the temperature at 105°C ~ 110°C.
5.3.2 Normal nitrogen oven (Figure 2). it can control the temperature at 105°C
~ 110°C; in the thermostatic region is installed a metal cartridge in the size of
200mm × 100mm × 60mm. In the cartridge, there is one tray which can
accommodate 6 weighing bottles. At one end of the cartridge is provided with a
nitrogen inlet, which is connected through a silicone tube to the nitrogen cylinder,
and the entrance is covered by several layers of metal mesh, so as to disperse
the gas; the other end has a small door, so as to allow the free access of the
tray, being used as nitrogen outlet.
soaked with water, AND stored in a sealed container for use). USE double layer
filter paper to wrap it; USE hand to forcefully grip it; PLACE it at the upper sieve
in the humidity chamber (5.12). Inside the chamber is placed two sieves, the
upper sieve aperture is 0.60mm AND the lower sieve aperture is 0.45mm, AND
on each sieve is placed some permanent wet paper (5.11). Then MIX the coal
sample and permanent wet paper, and MAKE the coal mass scatter and fall
onto the below sieve. REPEAT this operation, until the coal sample falls onto
the bottom Dowling paper. TAKE 1g ~ 2g of coal sample from it; PLACE it into
a known mass weighting bottle; PAVE it level; PLACE it in the humidifier.
7.3 Humidity regulation
PLACE the weighing bottle on the weighing bottle holder in the humidifier; USE
the positioning pin to position the weighing bottle (just below the gas circulator
bell mouth); OPEN the weighing bottle lid. COVER the humidifier; MAKE it
airtight; START the propeller, so as to make the nitrogen circulate for 10min at
the flow rate of 1L/min; then CLOSE the nitrogen inlet. RECORD the
humidification start time; when the coal sample basically reaches to humidity
balance (bituminous coal and anthracite generally requires 24h, lignite requires
24h ~ 48h), OPEN the humidifier cover; immediately COVER tightly the
weighing bottle; TAKE it out; WIPE the weighing bottle clean; LET it settle at
room temperature for 5min; then WEIGH it, accurate to 0.0002g. Afterwards, ...