Pyrolysis,carbonization, gasification and biomass conversion into the bioenergy are described in these slides. There all types of pyrolysis and carbonization and gasification which are usable into the bioenergy processing.

1. Non Conventional sources of Energy (EE-359)
Topic :- Biomass to Bioenergy Conversion
By:-
Abhay Kumar Jha

2. Biomass to Bioenergy Conversion
Biomass :-
Biomass is plant or animal material used for energy
production , or in various industrial processes as raw substances for a
range of products. It can be purposely grown energy crops, wood or
forest residues, waste from food crops, horticulture, food processing ,
animal farming , or human waste from sewage plants.
The five fundamental forms of Biomass energy which are use generally
1) Traditional domestics
2) Traditional industrial
3) Modern industrial
4) Chemical conversion
5) Biological conversion

3. (1) TRADITIONAL DOMESTIC:-
use in developing countries (fuelwood, charcoal and agricultural residues) for
household cooking (e.g. the "three stone fire"), lighting and space-heating. In this
role-the efficiency of conversion of the biomass to useful energy generally lies
between 5% to 15%.
(2) TRADITIONAL INDUSTRIAL:-
use of biomass for the processing of tobacco, tea, pig iron, bricks & tiles, etc,
where the biomass feedstock is often regarded as a "free" energy source. There is
generally little incentive to use the biomass efficiently so conversion of the
feedstock to useful energy commonly occurs at an efficiency of 15% or less.
(3) MODERN INDUSTRIAL:-
Industries are experimenting with technologically advanced thermal conversion
technologies. Expected conversion efficiencies are between 30 and 55%.
(4) CHEMICAL CONVERSION:-
technologies ("fuel cell") which are capable of by-passing the entropy-dictated
Carnot limit which describes the maximum theoretical conversion efficiencies of
thermal units.
(5) BIOLOGICAL CONVERSION:-
techniques, including anaerobic digestion for biogas production & fermentation
for alcohol.

4. Capture of Solar energy for fixation of carbon dioxide by plants
• By the process of photosynthesis in the presence of Carbon dioxide, water,
light and chlorophyll plants are able to produce their food in which the
energy is absorbed .
CO2 + H2O + light + chlorophyll Carbohydrate + O2
• For each gram mole of carbon fixed, about 470 kJ (112 kcal) is absorbed.
• It is estimated that the world’s standing terrestrial biomass carbon (i.e., the
renewable, above-ground biomass that could be harvested and used as an
energy resource) is approximately 100 times the world’s total annual
energy consumption.
• 80 to 90% of total biomass is forest terrestrial standing biomass.
• Marine biomass is the next after the forest biomass.
HIGH HYDROCARBON CONTAINING PLANTS:-
• Rubber tree (Hevea braziliensis) is plant in which High energy
hydrocarbon are formed by natural biochemical mechanism.
• Chinese tallow tree (Sepium sebiferum) is plant which afford high
triglycerides formed by natural biochemical mechanism.

5. Biomass Conversion Technologies
• Biomass-to-energy conversion technologies deals with the feedstock which
can be highly variable in mass and energy density, size, moisture content,
and intermittent supply. Therefore, modern industrial technologies are
often hybrid fossil-fuel/biomass technologies which use the fossil fuel for
drying, preheating and maintaining fuel supply when the biomass supply
is interrupted.
Thermochemical
treatment
Or
Biochemical
treatment
Biomass
Biowaste
Other
byproducts
Bioenergy
or
Biofuel

6. Thermochemical Processes
• These processes do not necessarily produce useful energy directly,
but under controlled temperature and oxygen conditions are used to
convert the original biomass feedstock into more convenient forms
of energy carriers, such as producer gas, oils or methanol.
A) Pyrolysis B)Carbonization C) Gasification D)Catalytic Liquification
(A)Pyrolysis:-
• Pyrolysis is the application of heat to a feedstock in the absence of
oxygen to break down the long chain molecules into short chain
molecules. Typically the feedstock is biomass or waste, and the
process is used to produce a syngas (a mixture of hydrogen, volatile
organic compounds, and carbon monoxide).
• Pyrolysis is a process of chemically decomposing organic matter at
elevated temperature in absence of oxygen . The process typically
occurs at above 430 degree Celsius and under pressure.
• This process simultaneously involves the change of physical phase
and chemical composition and is an irreversible process.

7. Different types of Pyrolysis:-
1. Slow pyrolysis 2.Fast Pyrolysis 3. Flash Pyrolysis
1.Slow pyrolysis:-
Slow pyrolysis is the slow heating of organic material in absence of
oxygen. Instead of combusting, the volatiles from the organic material evaporate
partly, and a product (charcoal) remains, consisting for a large part (normally 80%)
of carbon.

8. 2.Fast pyrolysis:-
Fast pyrolysis is a process in which organic material are rapidly heated
to 450 to 600 degree Celsius in the absence of air. Under these conditions, organic
vapors , pyrolysis gases and charcoal are produced. The vapors are condensed to bio
oil typically , 60 to 75 % of the feedstock is converted into oil.

9. 3.Flash pyrolysis:-
Flash pyrolysis (sometimes called very fast pyrolysis), characterized by
rapid heating rates and high reaction temperature 900-1300 degree Celsius, has been
shown to afford high yields of bio-oil with low resulting water content and
conversion efficiencies of up to 70%.

10. Carbonization
• Carbonization is the conversion of organic matters like plants and dead
animal remains into carbon through destructive distillation.
• During carbonization most of the volatile components of the wood are
eliminated; this process is also called “dry wood distillation.”
• Carbon accumulated mainly due to a reduction in the levels of hydrogen
and oxygen in the wood.
• The wood undergoes a number of physic chemical changes as the
temperature rises. Between 100 and 170 most of the water evaporated;
between 170 and 270 gases develop containing condensable vapours.

11. Fig:-Schematic diagram of Carbonization

12. Gasification
• Gasification is the process that converts biomass or fossil fuel based
carbonaceous materials into carbon monoxide, hydrogen, and carbon
dioxide.
• This is achieved by reacting the material at high temperature , without
combustion , with a controlled amount of oxygen or steam.
• Biomass can also serve as the original source of hydrogen via partial
oxidation or steam reforming to yield an intermediate hydrogen-containing
product gas.
• Hydrogen would then effectively act as an energy carrier from the biomass
to CO2 to yield a substitute or synthetic natural gas (SNG).
• Gasification requires temperatures of about 800°C and is carried out in
closed top or open top gasifiers. These gasifiers can be operated at
atmospheric pressure or higher.

13. Fig:-Diagram of Gasification process