Thermo chemical conversion

Thermo chemical conversion

1. THERMO CHEMICAL CONVERSION

2. Biomass origin -Resources –Biomass
estimation.
Thermo chemical conversion –Biological
conversion, Chemical conversion
Hydrolysis & hydrogenation, solvolysis,
biocrude, biodiesel power generation gasifier,
biogas, integrated gasification.

26. Pyrolysis is the thermal decomposition of biomass
occurring in the absence of oxygen.
It is the fundamental chemical reaction of both the
combustion and gasification processes and occurs
naturally in the first two seconds.
The products of biomass pyrolysis include biochar, bio-
oil and gases including methane, hydrogen, carbon
monoxide, and carbon dioxide.
Which can be successfully used for the production of
heat, power and chemicals.

27. Depending on the thermal environment and the final
temperature, pyrolysis will yield mainly biochar at low
temperatures, less than 450
0
C, when the heating rate is
quite slow
Mainly gases at high temperatures, greater than 800
0
C,
with rapid heating rates.
At an intermediate temperature and under relatively
high heating rates, the main product is bio-oil.
Pyrolysis offers a flexible and attractive way of
converting solid biomass into an easily stored and
transported liquid

29. The efficiency and nature of the pyrolysis process is
dependent on the particle size of feedstocks.
Most of the pyrolysis technologies can only process
small particles to a maximum of 2 mm keeping in
view the need for rapid heat transfer through the
particle.
The demand for small particle size means that the
feedstock has to be size-reduced before being used
for pyrolysis.

30. Pyrolysisprocesses can be categorized as slow
pyrolysis or fast pyrolysis.
Fast pyrolysis is currently the most widely used
pyrolysis system.
Slow pyrolysis takes several hours to complete and
results in biochar as the main product.
Fastpyrolysis yields 60% bio-oil and takes seconds for
complete pyrolysis. In addition, it gives 20% biochar
and 20% syngas.

31. Very high heating and heat transfer rates, which require
a finely ground feed.
Carefully controlled reaction temperature of around
500oC in the vapour phase
Residence time of pyrolysis vapours in the reactor less
than 1 sec
Quenching (rapid cooling) of the pyrolysis vapours to
give the bio-oil product.

32. Biochar can increase the available nutrients for plant
growth, water retention and reduce the amount of
fertilizer by preventing theleaching of nutrients out of
the soil.
Biochar reduces methane and nitrous oxide emissions
from soil, thus further reducingGHGs emissions.
Biochar can be utilized in many applications as a
replacement for other biomass energy systems.
Biochar can be used as a soil amendment to increase
plant growth yield.

33. Produces few air emissions due to limited use of
oxygen
Replaces coal and natural gas as viable fuel sources,
causing a reduction in climate change
Produces useful products for multiple applications
Can be easily implemented in combined heat and
power
More efficient than the Thermal power plant (70% vs.
40%)
Pyrolysis plants are flexible and easy to operate
because they are modular.

34. The pyrolysis process is complex and requires high
operational and investment costs.
Further, an air purification installation is necessary in
order to further treat flue gases from the pyrolysis.
Produced ashes contain a high heavy metal content,
depending on the concentrations in the to-be-processed
flow.
These ashes are regarded as dangerous waste and must
also be disposed of.