analysis of coal

Analysis of Coal

Presented By,

Momina Noor M12-PG-01

Mahnoor Butt M12-CE-16

Nehal Imtiaz M12-CE-02

Sabahat Tahir M12-CE-12

Solid Fuel

Combustible

Non-Volatile

Volatile

Non-Combustible

MoistureInorganic

Ash

Analysis of Coal

Proximate Analysis

Ultimate Analysis

Proximate Analysis

Proximate Analysis

MoistureVolatile Matter

AshFixed

Carbon

Moisture

Content

Moisture content varies with

such factors as the mine from

which coal was removed, the coal

seam and the extent to which coal

has been exposed to weather.

High moisture content is

undesirable.

Determination Method Of Moisture Content

A weighed sample of -72 B.S is dried at a temperature of 104

to 110℃ in an inert atmosphere to constant weight. Atmosphere must be free from oxygen otherwise oxygen will

combine with the coal.

𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑜𝑓 𝑀𝑜𝑖𝑠𝑡𝑢𝑟𝑒 =𝐿𝑜𝑠𝑠 𝑖𝑛 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑐𝑜𝑎𝑙

𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑐𝑜𝑎𝑙 𝑡𝑎𝑘𝑒𝑛× 100

Effects of Moisture on Coal

Reduce the Calorific Value.

Increases the consumption of Coal.

Lengthens the time of heating.

VolatileMatter

Represents the portion of Coal

which is converted into volatile

products when the coal is heated

in the absence of air.

High Volatile Coals tend to burn

with a long flame and give much

smoke.

For maximum thermal efficiency,

volatile matter must be burned

completely.

Determination Method Of Volatile Matter

Heating a weighed and dried sample of coal in a covered

platinum crucible at 500 to 700℃ for 7 minutes. A high percentage of volatile matter means that a large proportion

of fuel has burnt as a gas..

𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑜𝑓 𝑀𝑜𝑖𝑠𝑡𝑢𝑟𝑒 =𝐿𝑜𝑠𝑠 𝑖𝑛 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑐𝑜𝑎𝑙

𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑐𝑜𝑎𝑙 𝑡𝑎𝑘𝑒𝑛× 100

Effects of Volatile Matter on Coal

Lower Ignition Temperature.

Lower Calorific Value.

Larger Volume for Combustion

Higher tendency to catch fire.

Ash

Coal ash is derived from clay, iron

pyrites, limestone, sand and other

mineral matter.

Ash is an inert material which

consumes heat and the disposal of

which represents an expense to

consumer.

Lower the proportion of ash, greater

the value of coal.

Determination Method Of Ash Matter

Heating the residue left after removal of volatile matter at 600 to 700℃ for half an hour without covering.

Measured ash value and original mineral matter is related as:𝑀𝑖𝑛𝑒𝑟𝑎𝑙 𝑀𝑎𝑡𝑡𝑒𝑟 = 1.15 × 𝐴𝑠ℎ

𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑜𝑓 𝑉𝑜𝑙𝑎𝑡𝑖𝑙𝑒 𝑀𝑎𝑡𝑡𝑒𝑟 =𝐿𝑜𝑠𝑠 𝑖𝑛 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑐𝑜𝑎𝑙

𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑐𝑜𝑎𝑙 𝑡𝑎𝑘𝑒𝑛× 100

Effects of Ash on Coal

Hard and Strong Coal.

Lower Calorific Value.

Produce more slag.

Forms an insulating layer for small values

Can be reduced by washing.

Fixed

Carbon

It is the pure carbon

present in coal.

Determination Method Of Fixed Carbon

Carbonaceous residue from the volatile matter test. Obtained by subtracting from 100 the sum of percentages of

volatile matter, moisture and ash content of coal.

𝐹𝑖𝑥𝑒𝑑 𝐶𝑎𝑟𝑏𝑜𝑛 = 100 − (𝑚𝑜𝑖𝑠𝑡𝑢𝑟𝑒 + 𝑣𝑜𝑙𝑎𝑡𝑖𝑙𝑒 𝑚𝑎𝑡𝑡𝑒𝑟 + 𝑎𝑠ℎ)

Effects of Fixed Carbon on Coal

Greater the Fixed Carbon, Higher the Calorific

Value.

Advantages of

Proximate Analysis

Relatively Quick.

Easily carried out in

laboratory.

Indication of coal’s

quality and type

Ultimate Analysis

Ultimate Analysis of Coal

Ultimate Analysis provides following data: Elemental Carbon Elemental Hydrogen Elemental Oxygen-usually determined by difference rather than

directly. Elemental Sulphur- both organic and inorganic Elemental Nitrogen-nominally about 1% by weight Heating Value

Advantages of Ultimate

Analysis

Gives information about

elementary constituents

of coal.

Useful in designing of

coal burning equipment

and auxiliaries

Thank You