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Coal Conversion Facts
Bases of Analysis Definitions
| As Received (AR) | - includes Total Moisture (TM) |
| Air Dried (AD) | - includes Inherent Moisture (IM) only |
| Dry Basis (DB) | - excludes all Moisture | | Dry Ash
Free (DAF) | - excludes all Moisture & Ash | The
Proximate Analysis of any coal – the % contents of Ash, Volatiles ,Fixed Carbon
– also Sulphur & Calorific Value can be expressed on any of the above basis.
Conversations
To obtain-
-multiply | Air
Dry | Dry Basis | As
received | | AR
by |
100-IM%
100-TM%
|
100
100-TM%
|
-----
| | AD by
|
-----
|
100
100-IM%
|
100-TM%
100-TM%
| | DB
by |
100-IM%
100
|
-----
|
100-TM%
100
|
[For DAF, multiply DB by 100/100-A]
Example
| |
AR | AD |
DB | DAF |
| TM | 11.0 | - | - | - |
| IM | 2.0 | 2.0 | - | - |
| Ash | 12.0 | 13.2 | 13.5 | - |
| Vol | 30.0 | 33.0 | 33.7 | 39.0 |
| FC | 47.0 | 51.8 | 52.8 | 61.0 |
| Sul | 1.0 | 1.1 | 1.12 | - |
Different Tools
Units
| Metric tonne (MT) | = 1000 kilograms, 2204.6 lb |
| Imperial or long ton (LT) | = 1016.05 kilograms, 2240 lb |
| Short ( U.S.) ton (ST) | = 907.19 kilograms, 2000 lb |
Conversations
| From MT : | to LT divide by 1.016
to ST divide
by 0.9072
| | From LT : | to MT multiply
by 1.016
to ST multiply by 1.12 | Calorific Value
Units
| Kcal/kg | - Kilocalories per kilogram | | MJ/kg* | -
Megajoules per kilogram | | Btu/lb | - British Thermal Units
per pound | * MJ/kg = 1 Gigajoules/tonne (Gj/t)
Gross & Net Calorific Values Gross CV
“or upper heating value “ is the CV in laboratory conditions. Net
CV , “lower heating calorific value in value” or “Net Effective Calories
(NEC) I s the useful calorific value in boiler plant. The difference is essentially
the latent heat of the water vapour produced. Conversations
- Units
From kcal/kg to MJ/kg divide kcal/kg by 238.8
From kcal/kg to Btu/lb
divide kcal/kg by 0.5556 | | | From MJ/kg to
kcal/kg multiply MJ/kg by 238.8
From MJ/kg to Btu/lb multiply MJ/kg by 430
| | | From Btu/lb to kcal/kg divide Btu/lb by
1.8
From Btu/lb to MJ/kg divide Btu/lb by 430 |
Conversions – Gross/Net (per ISO, for As Received figures)
| Kcal/kg | Net CV | =Gross
CV | - 50.6 H | - 5.85 M | - 0.191 O | | MJ/kg | Net
CV | =Gross CV | - 0.212 H | - 0.0245 M | - 0.0008 O |
| Btu/lb | Net CV | =Gross CV | -
91.2 H | - 10.5 M | - 0.34 O | - Where M is % Moisture;
H is % Hydrogen; O is % Oxygen (from ultimate analysis, also as received)
For typical bituminous coal with 10% M and 25% vol., differences between gross
and net calorific values are approx as follows: 260 kcal/kg
1.09
MJ/kg
470 Btu/lb 
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