1. Web.iitd.ac.in/~pmvs

2. BY Dr. P M V Subbarao Mechanical Engineering Department I I T Delhi
Analysis of Fuels BY
Dr. P M V Subbarao
Mechanical Engineering Department
I I T Delhi
An analysis to know the Rate of Generation of Natural Fuels...

3. ONE TIME RESOURCE INCOMING RESOURCE THERMAL FOSSIL FUEL SOLAR
SOLAR ENERGY
INCOMING
RESOURCE
CO2 + H2O
PHTOSYNTHESIS
SOLAR
RADIATION
WINDS
VEGETATION
VELOCITY
CHEMICAL ENERGY
THERMAL
WAVE
WIND ENERGY
CLOUDS
OCEAN
THERMAL
ENERGY
FOSSILIZATION
RAINS
HYDRO ENERGY
COAL
FOSSIL FUEL
PETROLEUM
NATURAL GAS

4. A tree converts disorder to order with a little help from the Sun
The building materials are in a highly disordered state - gases, liquids and vapors.
The tree takes in carbon dioxide from the air, water from the earth as well as a small amount from water vapor in the air.
From this disordered beginning, it produces the highly ordered and highly constrained sugar molecules, like glucose.
The radiant energy from the Sun gets transferred to the bond energies of the carbons and the other atoms in the glucose molecule.
In addition to making the sugars, the plants also release oxygen which is essential for animal life.

5. First Law Analysis of Photosynthesis:SSSF
m CO2
m water
m vegetation Q W
m Oxygen
Conservation of Mass:
First Laws for furnace in SSSF Mode:

6. First Law Analysis of Photosynthesis:SSSF
Species Conservation Equation:
Conservation of Mass:
First Laws for a plant in SSSF Mode:

7. Fossil Fuels
After food, fossil fuel is humanity's most important source of energy. There are three major fuels -- coal, oil and natural gas.
Coal & Natural gas are used primarily to produce electricity. It therefore provides us with light, motive power from electric motors, and our many electronic devices.
Oil gives us our mobility, our cars, planes, trains, trucks and boats.
Natural gas is also used primarily to produce heat, for our buildings, hot water, and industrial processes.
Coal is our most abundant fossil fuel resource.
Coal is a complex mixture of organic chemical substances containing carbon, hydrogen and oxygen in chemical combination, together with smaller amounts of nitrogen and sulfur.
This organic part of coal has associated with it various amounts of moisture and minerals.

12. Fossilization : Bio - Chemical
Peat deposition is the first step in the formation of coal.
The humid climate of the Carboniferous Period (360 to 286 million years ago), which favoured the growth of huge tropical seed ferns and giant nonflowering trees, created the vast swamp areas
As the plants died and fell into the boggy waters, which excluded oxygen and killed bacteria, they partially decomposed but did not rot away.
The vegetation was changed into peat, some of which was brown and spongy, some black and compact, depending on the degree of decomposition.

13. First Law Analysis of Formation of Peat :SSSF
m CO2
m vegetation Q
m Peat
m CH4
Species Conservation Equation: W
Conservation of Mass:
First Laws for furnace in SSSF Mode:

15. Peat
Peat is The first stage in the formation of coal from wood (cellulose).
Rate of reaction : 3cm layer per 100 years.
Light brown fibrous at the surface and colour becomes darker with depth.
Typical Composition:
Moisture : 85%, Volatile Matter : 8 %, Fixed Carbon : 4%, Ash : 3%.
Calorific Value : 2700 kJ/kg.
Occurrence of Peat : Niligiri Hills and banks of Hooghly.
Sun dried Peat is very useful as a fuel with following composition:
Moisture : 20%, Volatile Matter : 50 %, Fixed Carbon : 25%, Ash : 5%
Bulk density : 300 kg/m3 and low furnace temperature and efficiency.
Products from Peat: Charcoal,Producer gas.

16. Secondary Transformation : Geo-Chemical Stage
The decayed vegetation was subjected to extreme temperature and crushing pressures.
It took several hundred million years to transform the soggy Peat into the solid mineral.
20 m of compacted vegetation was required to produce 1 m seam of coal.
This is called as coalification or coal forming.
The extent to which coalification has progressed determines the rank of coal.

17. Coalification
Coalification is the process of converting living biomass into coal.
Peat is the precursor of coal, and is what is formed in the first phases.
The coalification process is roughly comparable to baking a cake, but on a grand physical scale and time scale.
The ingredients are first mixed and the action of microorganisms (yeast in the case of a cake, bacteria and fungi in peat) begin to transform the dough. 
Baking kills the yeast and chemically alters the dough from a moist, plastic material into a rigid solid.
In coalification, peat is degraded by both microorganisms and chemical reactions, such as oxidation.
In the process, cellulose is substantially lost and the lignin chemical components are transformed. (Cellulose and lignin are the major structural biopolymers in plants.)
Oxygen content of the peat decreases, which increases the carbon content. Water content also decreases.

18. The ratio of aromatic carbons (graphite or charcoal-like character) to aliphatic carbons (oil-like carbons) also begins to increase. 
As the peat is buried deeper and deeper, the temperature gradually rises.
There is no oxygen input now and all biological activity has stopped. Oxygen continues to be lost and aromatic carbon increases even more.
There are all sorts of other reactions that the organic material is undergoing.
The details are still not clear.
Condensation reactions, as well as depolymerizations, are occurring. By the way, the temperature is not very hot.
It probably doesn't get any higher than 150 C. But it cooks for millions of years.
Then the land begins rising, erosion removes the upper layers.
Man comes along and finds that nature has just baked a coal and taken it out of the oven.

19. Modeling of Coalification
Peat to Enriched peat: (mostly due to heating)
Enriched peat to lignite: (mostly due to pressure &heating)
lignite to Sub-bituminous: (mostly due to pressure &heating)
Sub-bituminous to High volatile Bituminous:

20. High Volatile Bituminous to Medium volatile Bituminous:
Medium Volatile Bituminous to Low volatile Bituminous:
Low Volatile Bituminous to semi Anthracite:
Semi Anthracite to Anthracite:

21. Characteristics of Coal
Sulfur Content : Coal with sulfur > 5% is not recommended for combustion.
Weatherability : Weathering or Slacking Index -- An indication of size stability -- Denotes the tendency to break on exposure to alternate wet and dry periods Weathering index is the percentage of of coal passing through a sieve having 170 mm2 openings.
Grindability Index : A measure of relative ease of grinding coals or the power required for grinding coals in a pulverizer G = 6.93 W W is the weight of sample passing through 200 mesh size.
Burning Characteristics of Coal : Free burning coals and Caking Coals -- Caking index -- Pulverulent, sintered, weakly caked, caked and strongly caked.
Ash Fusion temperature -- The temperature where the ash becomes very plastic -- Design of ash handling system. -- Stoker furnace cannot use low ash fusion temperature coals.

22. Analysis of Coal Proximate Analysis & Ultimate Analysis.
Proximate analysis - to determine the moisture, ash, volatiles matter and fixed carbon
Ultimate or elementary analysis - to determine the elemental composition of the coal
The Energy content -- CFRI Formulae --
Low Moisture Coal(M < 2% ) -- CV (Kcal/kg) = 71.7 FC (VM-0.1 A) - 60 M
High Moisture Coal(M > 2%) -- CV(kcal.kg) = 85.6 {100 - (1.1A+M)} - 60 M
Where, M, A, FC and VM denote moister, ash , fixed carbon and Volatile mater (all in percent), respectively.