Pyrolysis renewable energy resources

1. RENEWABLE ENERGY RESOURCES
Lecture # 20
Presented by:
Dr. Bilal Ahmad Zafar Amin
Thermochemical conversion-
pyrolysis
Solar Energy
Wind Energy
Biomass Energy
Thermal Energy
Renewable
Resources
Oil
Coal
Natural Gas
Nuclear
Non-Renewable
Resources

2. Week # 11, Lecture # 2 Renewable Energy Resources
 Concept of thermochemical conversion-pyrolysis
 Pyrolysis of Cellulose- major structural compound
 Pyrolysis, environmental perspective
 Factors affecting pyrolysis process
 Visualization of Biomass Pyrolysis process
 Visualization of Biomass Pyrolysis conversion technology
 Classification of pyrolysis process
 Bio-char, bio-oil and syngas as pyrolysis products
 Pyrolysis of rice husk, advantages and limits of pyrolysis
Lecture Outlines:

3.  Biomass pyrolysis is the thermal decomposition of biomass occurring in the
absence of oxygen.
 It is the heating of biomass in a closed vessel at temperatures in the range
500oC- 900oC in absence of O2/air or with steam. It produces solid, liquid and
gases.
 It is the fundamental chemical reaction that is the precursor of both the
combustion and gasification processes and occurs naturally in the first two
seconds.
 The products of biomass pyrolysis include biochar (Carbonization), bio-oil
(Liquefaction) and gases (Gasification) including methane, hydrogen, carbon
monoxide, and carbon dioxide.
 The pyrolysis process can use all type of organic materials including plastic and
rubbers.
Week # 11, Lecture # 2 Renewable Energy Resources
Thermochemical Conversion
Pyrolysis

4. Biomass/
Organic residue
C
C
C
C
C
C
C
C
No Oxygen (- O2) 500 OC - 900 OC
Irreversible process
Pyro - Solid
Pyro - Liquid
Pyro - Gas
Phase transition
Syngas Bio - oil Bio - char
Week # 11, Lecture # 2 Renewable Energy Resources
Pyrolysis? Pyro = heat Lysis = break down
Pyrolysis is a chemical reaction that involves the molecular breakdown of larger molecules into
smaller molecules in the presence of heat and absence of oxygen. Pyrolysis is also known as
thermal cracking, thermolysis, depolymerization.

5. Week # 11, Lecture # 2 Renewable Energy Resources
Pyrolysis of Cellulose- major structural compound

6.  Biomass pyrolysis has been attracting much attention due to its high efficiency
and good environmental performance characteristics.
 It also provides an opportunity for the processing of agricultural residues, wood
wastes and municipal solid waste into clean energy.
 In addition, biochar sequestration could make a big difference in the fossil fuel
emissions worldwide and act as a major player in the global carbon market with
its robust, clean and simple production technology.
Week # 11, Lecture # 2 Renewable Energy Resources

7.  Temperature:
Depending on the thermal environment and the final temperature, pyrolysis will yield
mainly biochar at low temperatures, less than 450 0C, when the heating rate is quite slow, and
mainly gases at high temperatures, greater than 800 0C, with rapid heating rates. At an
intermediate temperature and under relatively high heating rates, the main product is bio-oil.
 Size, Scale & Location:
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. Pyrolysis can be
performed at relatively small scale and at remote locations which enhance energy density of
the biomass resource and reduce transport and handling costs.
 Moisture:
A wide range of biomass feed stocks can be used in pyrolysis processes. The pyrolysis
process is very dependent on the moisture content of the feedstock, which should be around
10%. At higher moisture contents, high levels of water are produced and at lower levels there is
a risk that the process only produces dust instead of oil. High-moisture waste streams, such as
sludge and meat processing wastes, require drying before subjecting to pyrolysis.
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Factors affecting Pyrolysis process

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The Biomass Pyrolysis Cycle

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Visualization of Biomass Pyrolysis process

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Visualization of Biomass Pyrolysis Bio -oil Conversion Technology

11. Electricity Electricity
Biomass
Pyrolysis
Bio-oil Char Fuel gas
Storage
Charcoal
Storage
Engine
Turbine
It is the process of conversion of biomass to
liquid (bio-oil), solid (charcoal) and gaseous
(fuel gases) products by heating in the
absence of air at 500-900 °C.
There are three types of pyrolysis : Fast
pyrolysis, Flash pyrolysis, Conventional/Slow
(Carbonization) pyrolysis.
Fast pyrolysis process has high heating value
and heat transfer rate and completes within
seconds. Fast pyrolysis yields 60% bio-oil,
20% bio-char and 20% biogas.
Flash pyrolysis is the type of fast pyrolysis, in
which 80% bio-oil is obtained at keeping
temperature low. If flash pyrolysis is used for
converting biomass to bio-crude, it has up to
80% efficiency.
Slow/Conventional pyrolysis takes more
time than fast pyrolysis, it also has low
temperature and heating values. In this process
mostly carbon (35%) is left as residue
(carbonization).
Week # 11, Lecture # 2 Renewable Energy Resources
Classification of pyrolysis & production of electricity

12. Pyrolysis mode
Conditions
Temperature,
residence time, heat
transfer rates
Product distribution (wt %)
Bio-oil
(Liquid)
Charcoal
(Solid)
Syngas
(Gas)
Fast pyrolysis
800 °C to 1000 °C,
< 0.5 second,
>1000 °C/sec
65 % 24 % 10 %
Flash pyrolysis
500 °C to 600 °C,
~ < 2 second,
>1 °C/sec
75 % 12 % 13 %
Slow pyrolysis
(carbonization)
250 °C to 300 °C,
long residence time
(hours to a day),
0.1 to 0.5 °C/sec
30 % 35 % 35 %
Week # 11, Lecture # 2 Renewable Energy Resources
Pyrolysis modes categorized by temperature, residence
time, and heat transfer rate

13.  Syngas is made up of carbon monoxide, and hydrogen (CO + H2, 85%) with
smaller amounts of carbon dioxide and methane.
 Syngas has a high calorific value so it can be used as a fuel to generate
electricity or steam.
 It is used as a basic chemical in the petrochemical industry.
 Synthesis gas is one important intermediate to produce fuels for
transportation and chemicals.
 Currently, synthesis gas is produced mainly from natural gas, coal or by-
products from refineries.
 The usage of synthesis gas is about 50% to ammonia, 25% to hydrogen, and
the rest is methanol.
Synthesis Gas-Syngas
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Syngas production and utilization
Octane (gasoline) utilization as energy source

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 Gasoline, also spelled gasolene, also called gas or petrol, mixture
of volatile, flammable liquid hydrocarbons derived from petroleum
and used as fuel for internal-combustion engines.
 Gasoline is a mixture of many different hydrogen- and carbon-
containing chemicals (hydrocarbons).
 A typical gasoline mixture contains about 150 different
hydrocarbons, including butane, pentane, isopentane and the
BTEX compounds (benzene, ethylbenzene, toluene, and xylenes).
Octane | C8H18
Gasoline

16.  Pyrolysis of cellulose at a temperature higher than 300 °C,
and consequently higher heat transfer rate, with residence
time mainly shorter than a minute (few seconds), contains
various complex reactions to a large amount of Bio-oil.
 Bio-oil is the main product of flash and fast pyrolysis with
50 % to 70 % weight of the biomass. The ideal reaction
conditions for gaining a high amount of liquids are at the
temperature of app. 900°C using a heating rate of 1000
°C/s, under exclusion of oxygen in flash or fast pyrolysis,
with short residence time.
 Bio-oil is a dark brown liquid and has a similar
composition to biomass. It has a much higher density than
woody materials which reduces storage and transport
costs.
 Bio-oil is not suitable for direct use in standard internal
combustion engines.
Week # 11, Lecture # 2 Renewable Energy Resources
Bio-oil (Fast pyrolysis)

17.  Biochar is a fine-grained and porous organic substance, similar to charcoal,
intended to be added to soil for fertility improvement.
 It is a solid fraction of a pyrolysis process, a thermochemical decomposition of
organic materials obtained by the application of heat in the absence or limited
supply of an oxidizing agent, used to produce renewable energy.
 Some of the by products of this process can be condensed into bio-oil , a liquid
that can be upgraded to fuels like biodiesel and synthesis gas as syngas.
 The term biochar was originally associated with a specific type of production
known as “slow pyrolysis”. In this process, oxygen is absent, heating rates and
temperatures are relatively low.
 A charred material is also formed during gasification of biomass which involves
thermal conversion at very high temperature (800 oC) and in the partial presence
of oxygen.
Week # 11, Lecture # 2 Renewable Energy Resources
Biochar-slow pyrolysis (carbonization)

18. Rice Husk
 The outermost layer of the
paddy grain is the rice
husk, also called ricehull.
 Still often considered as
a waste product in the
rice mill & therefore often
either burned in the open
or dumped on wasteland.
 Rice husk has high
calorific value and often
can be used as a
renewable fuel.
Week # 11, Lecture # 2 Renewable Energy Resources

19.  Moisture free rice husk sample was taken in to a perforated holder and was
introduced in to the tubefurnace.
 The furnace was made air tight & heated electrically.
 Reactor temperature was recorded usinga digital thermometer.
 Pyrolyses were performedunder vaccum.(710-720mm Hg).
 A centrifugal pump was set to create & maintain the vaccum inside thepyrolyser.
 Temperature of pyrolyser was varied within400- 650°C.
 The mixture of liquid & gas was allowed to come out through vaccum line & set
at one side of the pyrolyser.
 The fluid from the pyrolyser was condensed in a series of ice cooled condenser
& bio-oil was obtained.
 Uncondensed gas was blownoff.
 The solid bio-char was collected from the pyrolyser as residue at the end of each
batch of pyrolysis.
Week # 11, Lecture # 2 Renewable Energy Resources
Steps in the pyrolysis of rice husk

20. Advantages o f pyrolysis
 Simple.
 Low cost technology.
 Capable of processing a wide variety of feedstock's producing gases, bio-oil,
biochemical &charcoal.
 Reduces greenhouse gas emissions and waste going to landfill.
 Produces a marketable product (electricity).
 Low risk of water pollution .
 Low risk of odours.
 High recovery rate of resources .
 Minimal risk of health consequences .
 Commercially proven technology.
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 Technology is stillevolving.
 Market are yet to be developed for char product and pyrolysis liquid.
Limitations

21. Thanks for your Attention