Coal Laboratory is needed to know
the quallity of coal both receiving from ship and delivering to silo. It can
also be used to match specifications coal from produsen or distribitor that is
sent before with the result of coal laboratory. Its ways are some analysis,
such as surface moisture or air dry loss
( ADL ), inherent moisture, residual moisture, volatillity, calory value, sulfure
content, ash content, fixed carbon. These analysis is called Proximate Analysis. It is divided into
two group in alalysis step, ADL and TGA
( Thermo Gravimetry Analysis ). The sampling is taken from coal yard or stock
pile.
Not only those, another funtion of
coal laboratory is to calculate coal burning efficiency in boiler. The sampling
is taken from Bottom Ash and Fly Ash. Its parameters that be done here are unburn carbon ( UBC ) analysis and loss on ignition / inert ( LOI ) analysis.
Simple Diagram in Proximate
Analisys :
figure 1. coal analysis
Here are the steps to get a parameter:
Þ
AIR DRY LOSS ( ADL )
1. Weigh ± 750 gr ( m1)
sample, and place it on enemel dish
2. Take the sample into the
oven ( temp = 40 – 45 0C )
3. If sample was already dry,
expose it to the air and desiccator to normal temperature
4. Weigh and record the weight
( m2 )
Þ
RESIDUAL MOISTURE ( RM )
1. Continue step no 4
in ADL above
2. Grind or crush the sample
to reduce size till 8 mesh
3. take 5 gram ( m1 )
sample, place it in the furnace ( temp = 110 0C ) for 2 hours
4. cool in the open air ( 5
min ), then cool in the desiccator ( 20 min ) till room temperature was
reached.
5. Weigh as soon as cold ( m2
)
Þ
INHERENT MOISTURE ( IM )
1. Weigh ± 750 gr sample from
stock pile, place it on enemel dish
2. Take the sample into the
oven ( temp = 40 – 45 0C )
3. Crush in 8 mesh, then crush
again in 60 mesh.
4. Sieve until get 100 mesh
5. Take 1 gram ( m1
) sample
6. Place in to the furnace (
Temp = 110 0C ), for one hour
7. cool in the open air ( 5
min ), then cool in the desiccator ( 20 min ) till room temperature was
reached.
8. Weigh as soon as cold ( m2
)
Þ
VOLATILLITY
1. Same with Step of Inherent
Moisture, differences are from step sixth.
2. Place in to the furnace (
Temp = 900 0C ), for 7 min
3. Cool in the open air ( 5
min ), then cool in the desiccator ( 20 min ) till room temperature was
reached.
4. Weigh as soon as cold ( m2
)
Þ
ASH CONTENT
1. Same with Step of Inherent
Moisture, differences are from step seventh.
2. Place in to the furnace (
Temp = 750 0C ), for 2 hours
3. Cool in the open air ( 5
min ), then cool in the desiccator ( 20 min ) till room temperature was
reached.
4. Weigh as soon as cold ( m2
)
Þ
SULFURE CONTENT
Here be used a
device called Sulfuric Analyzer, below is steps to its operate ;
1. Start Sulfuric Analyzer
2. Set temperature until 1250 0C
3. Press “ analyzer “ button
4. Show “ balance “ in screen,
place crucible in weigher
5. Press “ tare “ button
6. Fill crucible with sample (
preparated is like Inherent Moisture from step 1 – 5 ) until ± 0,35 gr
7. Press “ enter “ twice
8. Place that crucible in
elevator
9. Wait untill screen show the
number. This device reads as SO2. Thus, to know sulfure content must
be converted by multiply with 0,5.
Þ
CALORY VALUE
Use Bomb
Calorimeter.
1. Start Sulfuric Analyzer
2. Fill crucible with sample (
preparated is like Inherent Moisture from step 1 – 5 ) until ± 1 gr
3. Setting the calorimeter ;
temperature of demin water, ignition wire, electrode connector, room
temperature must be stable ( use air conditioner )
4. Place the sample in the
combustion capsule and insert it in bomb calorimeter
5. Run the analyzer and let it
proceed the measurenment
Þ
FIXED CARBON
Þ
TOTAL MOISTURE
Þ
UNBURN CARBON ( UBC )
1. Weigh ± 10gr sample from
fly ash or bottom ash, place it on enemel dish
2. Take the sample into the
oven ( temp = 40 – 45 0C )
3. Crush in 8 mesh, then crush
again in 60 mesh.
4. Take 1 gram ( m1
) sample
5. Place in to the furnace (
Temp = 750 0C ), for one hour
6. Cool in the open air ( 5
min ), then cool in the desiccator ( 20 min ) till room temperature was
reached.
7. Weigh as soon as cold ( m2
)
Þ
LOSS ON IGNITION / INERT
1. Weigh ± 10gr ( m1
) sample from fly ash or bottom ash, place it on enemel dish
2. Place in to the furnace (
Temp = 950 0C ), for 30 min
3. Cool in the open air ( 5
min ), then cool in the desiccator ( 20 min ) till room temperature was reached.
4. Weigh as soon as cold ( m2
)
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