CONTENTS Section-1: Coal Sampling & Preparation of coal Sample as per IS 436 (Part I/Sec I) 1964
Section-2: Proximate Analysis (As Per IS 1350 Part I) A. Total Moisture &
B. Air Dried Moisture C. Ash D. Volatile Matter
Section -3 Gross Calorific Value (As Per IS 1350 Part II)
Section-1: Coal Sampling & Preparation of coal Sample As Per IS 436 (Part I/Sec I) 1964
The Sample Collected will Prepared for Further Analysis as under for Total Moisture. Gross Sample (As per Coal Yard Management SOP) Approx 10 Kg
Crush the complete Sample to 12 .5 mm Size in Crusher
Reduce Sample to 1 Kg by Coning & Quartering. Keep the Sample in a tray for Air Dry for 24 Hrs in Lab Condition & record the Wt Loss for Determining The Surface Moisture. (X)
Reduce The Sample to 2.9 mm by further crushing. Take 10 gms for oven drying at 108+/-2 o C for 1 to 1.5 Hrs & record the weight loss. (Y)
Section-1: Coal Sampling & Preparation of coal Sample As Per IS 436 (Part I/Sec I) 1964
The Sample Collected will Prepared for Further Analysis as under for Proximate Analysis. Gross Sample (As per Coal Yard Management SOP) Approx 10 Kg
Crush the complete Sample to 12 .5 mm Size in Crusher
Reduce Sample to 1 Kg by Coning & Quartering. Keep the Sample in a tray for Air Dry for 24 Hrs in Lab Condition & record the Wt Loss for Determining The Surface Moisture.
Reduce The Sample to 500 gms & Pulverise to 212 Micron for Proximate Analysis (Ash, VM, IM & GCV)
Section-2:
Proximate Analysis
A. Total Moisture: For Determining Total Moisture We followed two stage methods (6.4.1 and 6.4.2 as per IS: 1350 Part I Page No 8 & 9).
Stage I (Air Drying): Procedure: Take 1.0 Kg of 12.5mm passing sample accurately weigh the sample & the container to nearest 0.5gm (M1).Transfer the sample from container to metal tray approx 1000 Sq cm in size & spread evenly on tray. Weigh the empty container (M2).Record the sample weight (M1M2).Allow sample in tray to air dry at atmospheric condition in well ventilated place free of dust. Take the drying to be complete when the change in mass during an hrs less than 0.1 % of sample (usually it take 1 days in dry season & more time in rainy season. Record the Mass.
Stage II (Oven drying)
Procedure: Equipment required: 1. Ventilated drying Oven in which constant temp & uniform temp
108+/-2
o
C can be maintained
2. Weighing Vessel: 40 sq cm, Made of Silica, glass or SS
Procedure
⇒
Heat the empty vessel at 108+/-2
o
C & weigh after cooling
20 Minutes (M1). ⇒
Crushed the air dried material to 2.90 mm IS sieve or take
212 micron passing sample prepared for Proximate analysis. ⇒
Spread uniformly 10 Gms of crushed material and weigh.
o
⇒
Heat the sample in oven at 108+/-2
C for 1.5 Hrs to 3 hrs.
⇒
Remove the sample from oven & Cool the sample in
Desiccators for 20 minutes & Note down the weight of sample (M2). Record the weight Loss (M1-M2)
Calculation: X= % Loss in mass of original sample in air drying Y= % Loss in mass of air dried sample on oven drying.
Total Moisture(TM) %=X + Y (1- X/100)
B.
Air Dried Moisture For Determining Moisture in sample we followed one stage method (6.3.2 as per IS: 1350 Part I Page No 7 & 8).
Equipment required: 1. Ventilated drying Oven in which constant temp & uniform temp
108+/-2
o
C can be maintained
2. weighing Vessel: 10 sq cm, Made of Silica, glass or SS
Procedure ⇒
Heat the empty vessel at 108+/-2
o
C & weigh after cooling 20
Minutes. ⇒
Take approx 1.5 gm coal passing 212 micron IS sieve .Spread uniformly 1.5 gms of coal sample so that there is not more than 0.15 gms per sq cm area & weigh the sample (M1). o
⇒
Heat the sample in oven at 108+/-2
C for 1.0 Hrs to 1.5 hrs.
⇒
Cool the sample Desiccators for 20 minutes & Note down the weight of sample (M2).
⇒
Record the weight Loss (M1-M2) & express as percentage.
C. Volatile matter (IS 1350 PART I-1984 PAGE No 18 to 23)
Equipment required: 1. Silica crucible with lid as per IS 2. Muffle furnaces in which a zone of constant & uniform temp of
900+/-10 o C can be maintained.
Procedure: ⇒
Take approx 1.0 Gms of Air dried sample passing 212 micron IS sieve.
⇒
Heat the crucible in furnace for 7 minute with lid & than cool on metal surface for five minute & than cool for 10 minutes in desiccators.
⇒
Take 1.0 Gms of coal sample in crucible & covered with lid & spread sample uniformly in crucible.
⇒
Heat the crucible with lid in muffle furnace for 7 minutes. Please note that Moisture of sample should determine simultaneously.
⇒
Take out the sample from muffle furnace & cool in same manner as above. Record the weight of crucible.
Calculation: Mo
=
% Moisture in the sample on air dried basis.
M1
=
mass in g of empty crucible with lid
M2
=
mass in g of crucible with lid and sample before heating
M3
=
mass in g of crucible with lid and sample after heating
% VM
=
(M2-M3) x 100/ (M2-M1)
- Mo
D. Ash (IS 1350 PART I-1984 PAGE No 24 to 25)
Equipment required:
1 Muffle Furnace : Capable of giving substantially uniform zone of 500
o
C in 30 Min from cold, of being raised to 815 +/-10
o
C in a further
30 to 60 Min and Maintaining this Temperature up to end of run up period. Ventilation shall be such that five air changes per minute. 2 Dish: of Silica, porcelain, platinum, 10 to 15 mm deep, of such size that spread of sample does not exceed 0.15 g/cm 2.
Procedure:
⇒
⇒
Thoroughly mix 212 micron passing Air dried coal sample. Weigh the clean & dry Dish with lid. Take 1 to 2 Gms of sample in dish according to size of dish. Distribute the material so that spread of sample does not exceed 0.15 g/cm 2.
⇒
Insert the uncovered dish into muffle furnace at room temperature, raise the Temp to 500 in 30 Min and 815 +/-10
o
C
in a further 30 to 60 Min and maintain at this temperature for 60 min. ⇒
Cover the dish with its lid.
⇒
Remove from muffle furnace & allow cooling down on metal surface for 10 min & placing the dish into desiccators for another 15 min. Weigh the Dish & observe the color of Ash.
⇒
If Chemist feel He can further put the Dish in muffle furnace till weight loss is less than 0.001gm.
Calculation Ash % by mass =
100 X (M3 - M4) / (M2-M1)
M1
=
mass in g of dish,
M2
=
mass in g of dish and sample,
M3
=
mass in g of dish and ash, and
M4
=
mass in g of dish after brushing out the ash
and on reweighing.
Section -3 Gross Calorific Value (As Per IS 1350 Part II) 1.
Determination of water equivalent of Bomb calorimeter
Water Equivalent is Heat capacity of Bomb calorimeter which indicates heat required to raise 1
o
C of bomb. It should be checked once in Three
Month & verified every Week. If weekly result exceed +/-10 Cal/gms repeat the procedure.
Please note following Calorific value of cotton Nichrome wire
Procedure:
=4180 cal/g = 335 cal/g
⇒
Dry the benzoic acid by heating more than 5 o C above its melting point 121 o C which will cause fusion. Compress it in the form of a capsule or briquette weighing approx 0.955 Gms.
⇒
Connect a piece of firing Nichrome wire 0.1 mm diameter across the terminal of bomb. Tie a known weight cotton thread to firing wire & arrange ends of cotton thread so that they touch sample. Record Length of nichrome wire (6.0 mm) & cotton thread (10 mm)for future testing.
⇒
Put 1 ml of distilled water in the bomb, assemble the bomb and charge with oxygen to a pressure of 30 atm (28-30 Kg/sq cm)
⇒
Put sufficient qty of water in the calorimeter vessel to cover upper surface of bomb cap. Measured the qty of water & record the same.
⇒
Put the vessel into water jacket and assemble bomb & stirrer. Start the power of bomb and allow the temp to stabalise for five minutes.
⇒
Set Zero of firing unit & fire the bomb. Record the temp rise till temp stabilises & start to fall by 0.01
o
C. Record the Temp rise of
Bomb. ⇒
Stop the power supply of firing unit & dismantle the bomb.
Calculation: Weight of Crucible + Thread+ Nichrome wire
= M1
Weight of Crucible + Thread+ Nichrome wire+ Benzoic acid = M2 Weight of Benzoic acid Temp rise
=M2-M1 =dT
Calorific value of Benzoic acid
= 6319 cal/
gms Correction of heat of cotton & Nichrome wire ( E1 + E2) =34.98 cal
Water Eq T
= ((M2-M1) X Calorific value of Benzoic acid - (E1+E2)) / d
Note: Record at least five readings of Water Eq & take mean value of it for future calculation. We have ignore following correction for sake of simplicity
Take Approx 1.0 gms of air dried coal sample passing 212 micron IS sieve. Make pallet/Briquette in pallet machine.
⇒
Connect a piece of firing Nichrome wire 0.1 mm diameter across the terminal of bomb. Tie a known weight cotton thread to firing wire & arrange ends of cotton thread so that they touch sample. The length of Nichrome wire & cotton thread should be same as taken during determination of water equivalent/heat capacity of Bomb calorimeter.
⇒
Put 1 ml of distilled water in the bomb, assemble the bomb and charge with oxygen to a pressure of 30 atm ( 28-30 Kg/sq cm)
⇒
Put sufficient qty of water in the calorimeter vessel to cover upper surface of bomb cap. Measured the qty of water & record the same.
⇒
Put the vessel into water jacket and assemble bomb & stirrer. Start the power of bomb and allow the temp to stabalise for five minutes.
⇒
Set Zero of firing unit & fire the bomb. Record the temp rise till temp stabilises & start to fall by 0.01
⇒
o
C. Record the Temp rise of Bomb.
Stop the power supply of firing unit & dismantle the bomb.
Calculation Weight of Crucible + Thread+ Nichrome wire
= M1
Weight of Crucible + Thread+ Nichrome wire+ coal sample Weight of coal sample Temp rise
=M2-M1 =dT
= M2
Water Equivalent
GCV of Sample
=E
= ( E X ( M2-M1)- 34.98) / d T
= (Water Eq X Wt of Sample - Heat of Nichrome Wire & cotton thread)/ Temp
rise
Note: We have ignore following correction for sake of simplicity
