BIOOIL PRODUCTION FROM BIOMASS
(FAST PYROLYSIS)

BIOMASS CONVERSION ROUTES
Biochemical platform
• Ethanol
• Butanol
• Biogas
Thermochemical platform
• Combustion
• Pyrolysis
• Gasification
Carbon rich chains platform
(Biodiesel)
Combined Heat
and Power,
Fuels,
Chemical and
Materials
Biomass
Feedstock

THERMOCHEMICAL CONVERSION ROUTES

4
BIOOIL GENERATION TECHNIQUES
BIOMASS
Fast pyrolysis
Biooil
stabilization &
upgradation
Hydro-thermal
liquefaction
Hydro
processing
Syn-gas to liquid
fuel
Fischer-Tropsch
synthesis
Fermentation or
catalytic
conversion of
sugars
Enzymatic
hydrolysis
route

PYROLYSIS OF BIOMASS
 Pyrolysis means breaking down of materials in the absence of air. In a pyrolysis kiln
or gasifier, biomass is subjected first to heat which releases gases and volatile
materials according to the chemical equation
C H1.4 O0.6 Gas + Vapour + Charcoal
 Pyrolysis yields a residue of 10-25% charcoal. Thus pyrolysis can be called a partial
gasification process. The gases and vapours can be burnt directly, if sufficiently hot.
As they cool below about 400οC, the vapours begin to condense and form tars. The
pyrolysis vapour is typically 75-90% of the fuel mass. It consists of the fuel gases
CO and H2, CH4, the more complex volatile tars and some CO2 and H2O. The
resulting charcoal may be converted to gas by reaction with H2O or CO2

FAST PYROLYSIS
 Fast pyrolysis has been developed in the last decade as a method of producing a
liquid pyrolysis oil “biosyn” or “bio-crude” , from biomass with yields of 60-75%
liquid.
 In conventional slow pyrolysis process a pressure of 1 atmosphere and a
temperature of 300-400 ºC is employed in the absence of oxygen to obtain charcoal
as the main product.
 But in fast pyrolysis high heating rates are used at 450-600 οC with small particles
of biomass in the absence of oxygen and it is decomposed to give off mostly
vapours and aerosols and some charcoal. After cooling and condensation, a dark
brown mobile liquid is formed which has a heating value about half that of
conventional fuel oil.

ESSENTIAL FEATURES OF FAST PYROLYSIS PROCESS
 very high heating and heat transfer rates, that usually needs a finely
ground biomass
 carefully controlled pyrolysis reaction temperature of around 500 ºC
in the vapour phase, with shorter residence times of less than 2
seconds.
 Rapid cooling of the pyrolysis vapours to give the bio-oil product.
 The main product bio-oil can be obtained upto a maximum of 80% of
the weight of the dry feed, along with char and gas that are used with
in the process.

ADVANTAGES OF BIO-OIL
 The volume of oil is reduced to one-sixth of the biomass and hence
the storage space is very much reduced and the bio-oil can be handled
easily.
 Also, the cost of transport is reduced as compared to the raw biomass
 The bio- oil can be used for direct applications in the burners
replacing the furnace oi for steam production or power production.
 The bio-oil can be gasified in the presence of catalysts to yied
hydrogen-rich producer gas for use in the internal combustion engins
that can be used for power production or for stationary agricultural
operations in the stand-alone engines.

PROPERTIES OF BIO-OIL
Characteristics of oil
 Liquid fuel which does not mix with hydro-carbon fuels
 Not stable as fossil fuels
 Easy substitution for conventional fuels in many static applications in boilers,
engines, turbines.
 Heating value is about 40% of fuel oil or diesel by weight.
 Mild steel is attacked by the oil and the storage of oil should be in acid proof
materials like stainless steel or poly-olefins.
 Neutralization of oil is not recommended as it causes polymerization.
 The important property of oil is its instability. The viscosity of oil increases during
storage, due to (slow) polymerization and/or condensation reactions. Moreover this
ageing is accompanied by a slow increase in the oil’s water content. These reactions
are enhanced by the higher temperatures, exposure to oxygen or to ultra-violet light

10
STATE OF TECHNOLOGY BIOOIL PRODUCTION

PYROLYSIS
 Pyrolysis is thermal cracking of biomass in the absence of oxygen or air
- Cedric Briens
 Pyrolysis is the thermal decomposition of organic material at elevated
temperatures in the absence of gases such as air or oxygen - Green
peace
 Products : Solid (charcoal), Liquid (biooil) and Gas
 Heat introduced, O2 excluded
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PYROLYSIS OF BIOMASS
12
HEAT
BIOMASS
VAPOUR
CONDENSATION

Biomass pyrolysis

Biomass pyrolysis process
•Thermal decomposition of organic components in biomass starts at
350–550 °C and goes up to 700 –800 °C in the absence of
air/oxygen.
•The long chains of C, H & O compounds in biomass break down into
smaller molecules in the form of gases, condensable vapours (tars
and oils) and solid charcoal under pyrolysis conditions.
•Rate and extent of decomposition of each of these components
depends on the process parameters of the reactor temp, heating
rate, pressure, reactor configuration, feedstock etc

• Rapidly developing technology
• Added Value Economy
• Carbon negative solution Environment 
• Increased bulk and energy density Economy Environment 
• Biomass source can be decoupled from the energy utilization
• Potential to be self-sustaining energy-wise
ADVANTAGES OF PYROLYSIS OF BIOMASS

DIFFERENT MODE OF PYROLYSIS PROCESS
Mode Conditions Liquid (%) Solid (%) Gas (%)
Fast pyrolysis Reactor temperature above 500°C
Very high heating rates > 1000°C/s
Short hot vapour residence 1 s
75 12
char
13
Intermediate
pyrolysis
Reactor temperature 400-500°C
Very high heating rates 1 - 1000°C/s
Hot vapour residence 10-30 s
50 25
Char
25
Slow pyrolysis Reactor temperature 250-450°C
Low heating rates 1°C/s
Long solid residence hours - days
30 33
Char
35
Torrefaction Reactor temperature 100-150°C
Low heating rates 1°C/s
Solid residence time 30 min
0-5 77 23

FAST PYROLYSIS PRODUCTS
SOLID BIOMASS
Gases (10-20%)
(Mainly CO, CO2, CH4, H2, H2O)
Char (10-20%)
(Solid carbonaceous residue)
Tar (Biooil) (60-75%)
(High molecular weight liquids,
volatile at reaction temperature)

REACTION SCHEME
Biomass
425-600 oC
Gas
Biooil
Char
• Primary degradation to
form char and gases
• Secondary reactions,
polymerization, cracking
Chemical
Processes
• Heat transfer by conduction,
convection and radiation
• Pressure gradients
inside the degrading solid
• Surface regression,
crack formation, swelling, shrinkage
Physical
Processes
Char
Gas + Bio-oil

BIOOIL
 Biooil is dark brown, free-flowing organic liquids that are comprised of highly
oxygenated compounds
 biooil typically contains more than 300 chemical compounds.
 The synonyms for biooil include pyrolysis oils, pyrolysis liquids, bio-crude oil
(BCO), wood liquids, wood oil, liquid smoke, wood distillates, pyroligneous acid
and liquid wood.
 Not an oil as it is immiscible in petroleum oils

ADVANTAGES OF BIOOIL
• Environmental Considerations
oNo SOx emissions
oCO2 neutral
o50% lower NOx emissions than diesel fuel
 Renewable and locally produced
 CO2 / alternative fuel credit
 Storage and transportation
 Additional products (green chemicals)

BIOOIL PRODUCTION METHODS
Methods Treatment
condition/requirement
Reaction mechanism
/ Process description
Technique feasibility
Pros. Cons
Flash/fast pyrolysis • Higher temp (>500°C)
• Short residence time ( 1 s);
• Atmospheric pressure
• Drying necessary
Light small molecules are
converted to oily products
through homogenous
reactions in the gas phase
• High oil yield upto
80% on dry feed
• Lower capital cost
Poor fuel quality
Hydrothermal liquefaction (HTL)/
hydrothermal pyrolysis
• Lower temp (300-400°C);
• Longer residence time ( 0.2 – 1
h)
• High pressure (5-20 Mpa);
• Drying unnecessary
Occurs in aqueous medium
which involves complex
sequences of reactions
• Commercialized
• Bio oil with high
heating value and
low moisture
content
• Low oil yield (20-
60%)
• Need high pressure
equipment
• Higher capital cost
Hydro pyrolysis • High temp(350-600°C)
• Higher pressure (5-20 Mpa)
• Less residence time < 20 min
• Carrier gas : Hydrogen
Thermal decomposition at
high temp in the presence of
H2
• Low viscous oil in
high yield
• Low O2 content in
biooil
• Need high pressure
equipment
• Higher capital cost

BIOMASS
CONCEPTUAL PROCESS
ESP
BIOOIL
GAS
for export
Gas recycle
Recycle gas heater
and/or oxidiser
CHAR
Grinder
Quench
cooler
Free-
board
Reactor
Dryer
8
10
9
11
7
7
6
4
5
3
2
1
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REACTORS FOR FAST PYROLYSIS
Bubbling fluidized-bed reactor
Circulating fluidized-bed reactor
Rotating cone reactor
Vacuum reactor
Ablative reactor
Auger reactor

BUBBLING FLUIDIZED BED PYROLYZER

BUBBLING FLUIDIZED BED PYROLYZER
• Heated sand medium in anaerobic condition heats the biomass to 500°C, where it is
decomposed into char, gas, vapors and aerosols which exit the reactor by the conveying
fluidizing gas stream
• Charcoal is removed from cyclone separator
• Quenching system : Scrubbed gases, vapors and aerosols are rapidly cooled (<50ºC)
directly with a liquid immiscible (two liquids that don’t mix) in biooil or indirectly using
chillers (heat exchanger)
• Condensed biooil is collected and stored
• Non-condensable gas may be recycled or used as a fuel to heat the reactor
• Feedstock particle sizes : < 2-3 mm ( to ensure that the high heat rate requirement)
• Prior to recycling the syngas and residual biooil, aerosol droplets may be further
scrubbed in an electrostatic precipitator to remove finer particulates and aerosols

CIRCULATING FLUIDIZED BED PYROLYZER
• Similar to bubbling fluidized bed reactors but have
shorter residence times for chars and vapours
• Short residence times encountered in the reactor
result in higher gas velocities, faster vapor and
char escape and higher char content in the bio-oil
than bubbling fluidized beds
• Heat supply typically comes from a secondary char
combustor

CIRCULATING FLUIDIZED BED PYROLYZER

ROTATING CONE PYROLYZER
• It is function under pressure in which heat is transferred from
a hot surface which soften and vaporize the feedstock in
contact with sand – allowing the pyrolysis reaction to move
through the biomass in one direction
• With this arrangement, larger particles, including logs, can be
pyrolyzed without pulverizing them
• Important feature: There is no requirement for an inert gas medium, thereby resulting in smaller
processing equipment and more intense reactions
• The process is dependent on surface area, so scaling can be an issue for the larger facilities
• Biomass particles at room temp and hot sand are introduced near the bottom of a cone at the same time
• Biomass and sand are mixed and transported upwards by the rotation of the cone
• Pressures of outgoing materials are slightly above atmospheric levels

ROTATING CONE PYROLYZER

VACUUM PYROLYZER
 It is not a true fast pyrolysis, because the heat-transfer rate, both to and through the solid biomass, is
much slower than other reactors
 Thermal decomposition of biomass under reduced pressure
 Complex organic molecules decompose into primary fragments when heated in the reactor
 Fragmented products are vaporized and quickly withdrawn from the reactor by vacuum and then
recovered in the form of pyrolytic oils by condensation
 These fragments are often very high-boiling-point compounds; therefore, they could undergo further
cleavage to lower-boiling point fragments in the absence of an applied vacuum
 More-rapid volatilization under vacuum minimizes the extent of secondary decomposition reactions
 Chemical structure of the pyrolysis products more closely resembles the original structures of the
complex biomolecules that constitute the original organic material
 Temperature of 450 °C and Pressure of 15 kPa

ABLATIVE PYROLYZER
 Ablative pyrolysis relies on heat transfer occurring when a biomass
particle impacts and slides over a solid hot source
 It is substantially different in concept, compared to other methods of fast
pyrolysis, where the reaction is limited by the rate of heat transfer
through a biomass particle (small particles)
 Mode of reaction:
◦ analogous to melting butter in a frying pan: pressing down and moving the butter
over the heated pan surface can significantly enhance the rate of melting
◦ Speeds heat transfer; shearing action creates more surface area, which can then
contact the heat source, further increasing heat transfer

ABLATIVE PYROLYZER
• During ablative pyrolysis, heat is transferred from the hot reactor wall to “melt”
wood that is in contact with it under pressure
• Pyrolysis front moves uni-directionally through the biomass particle
• As the wood is mechanically moved away, the residual oil film both provides
lubrication for successive biomass particles and also rapidly evaporates to give
pyrolysis vapours for condensation.

AUGER PYROLYZER
 Mechanical mixing of biomass and a bulk solid heat
transfer medium
 Instead of the reactor vessel itself rotating, there are
mixing devices that rotate inside a stationary horizontal
reaction vessel
• Biomass and heat carrier are independently metered into the reactor and the heat carrier is heated
prior before entering the reactor
• As vapor products evolve they exit the reactor due to pressure differences and the biochar and the
heat carrier exit at the end of the reactor
• biochar does leave the auger reactor with the vapor products and is removed with cyclones
• A solid separator device can be used to remove biochar from the heat carrier material based on
differences in particle size or density
• Similar to CFB and rotating cone reactors, a combined heat exchanger and combustion reactor then
reheats the heat carrier before it is recirculated into the auger reactor

AUGER PYROLYZER

NEED FOR REACTOR DEVELOPMENT
 None of the reactor concepts described above fully satisfies all requirements, in their present state of
development, as a methodology for the production of an alternative liquid fuel with a reasonably
trouble-free operation, proven scale-up technology and economically competitive performance.
 Specific objectives that should be addressed in the design of a biooil production process include the
following
◦ Biooil vapour quenching requirements should be minimized, using a small recycle ratio (i.e., a
small gas/biomass feed ratio)
◦ Biomass pyrolysis reactor should operate at the minimum possible temp, preferably 400-420 °C
◦ An independent heat supply allows more design flexibility and easier control
◦ Preheating of the recycle product gas above 600 °C should be avoided, because this may form
micro particulate carbon, because of decomposition of CO or organic vapours
◦ Reactor should cause a minimum amount of char particle attrition

COMPARISON OF VARIOUS REACTORS

COMPARISON OF VARIOUS REACTORS

HYDRO THERMAL LIQUEFACTION
HTL involves direct liquefaction of biomass, with the presence of
water to directly convert biomass into liquid oil, with a reacting temp
of lower than 400° C
HTL conditions: Temp between 280 to 370oC and at 10- 25 Mpa
pressure
Products : bio-crude with a relatively high heating value, char, water-
soluble substances and gas

HTL PROCESS

CHEMISTRY OF HTL

CHEMISTRY DURING HTL
 Depending on the feedstock, biomass is composed of varying ratios of macro
molecules including carbohydrates (cellulose and starch), lignin, lipids and
proteins
 Initially, these macromolecules are broken down into their monomer units
 As the HTL process continues, the monomer units are further cleaved and broken
into smaller fragment molecules
 Fragmentation - to remove oxygen and other hetero atoms (e.g. nitrogen, sulphur,
phosphorous), leaving behind the initial C and H atoms in the form of low
molecular weight compounds
 This process maximizes the energy content of the biocrude oil and increases the
value and ability to refine the final product

HYDRO PYROLYSIS
 Thermal decomposition of an organic material under high
heating rates (about 500 ◦C/s) in a H2 environment
 H2 may be the only gas or may be diluted in an inert gas such
as N2.
 It can only be performed in systems that allow short vapor
residence times
◦fluidized bed reactors
◦ cyclone reactors

HYDRO PYROLYSIS
 Process can be catalytic or non-catalytic
 In order to ensure proper level of de-oxygenation, some groups have
employed a hydro-treating unit right after the fast hydro-pyrolysis reactor, so
that the volatiles coming from the first reactor are immediately upgraded in
the second unit.
 Products
◦ an organic phase containing a mixture of hydrocarbons (target product)
◦ an aqueous phase, along with char and permanent gases
◦ Coke, when catalyst is used, then small quantity of coke on the catalyst
surface may also be produced

a. Non-catalytic fast hydro pyrolysis
b. Catalytic fast hydro pyrolysis
c. Non-catalytic fast hydropyrolysis
with ex-situ hydrotreating
d. Catalytic fast hydropyrolysis
with ex-situ hydrotreating

ISSUES
o Feed
oSelection and preparation
oFractionation
oCharacteristics
oModification
oDrying, size and shape
Reactor
 Configuration
 Development
 Catalysts – good and bad
 Heat supply
 Scale up and scale limits
 Improved modelling
 Liquid
 Vapour condensation
 Aerosol capture
 Quality control
 Norms and standards
 Trading
 Gas
 Recovery
 Utilisation
 Char
 Separation
 Utilisation

 Cost reduction
• Results from optimisation
and consideration of all
above issues
 Learning
 Leads to cost reduction
 Applications
 Integration with upgrading
 Norms and standards
 Health and safety
 Transport
 Trading
 Environment
 User’s lack of familiarity
 Biorefineries
 Fuels, chemicals, biofuels
ISSUES

CHARACTERISTICS OF BIOOIL AND
METHODS FOR MODIFICATION
Characteristics Effect Solution
Contains
suspended char
• Leads to erosion, equipment blockage,
combustion problems due to slower
rates of combustion
• Sparklers can occur in combustion
leading to potential deposits and high
CO emissions
• Hot vapour filtration
• Liquid filtration
• Modification of the char for
example by size reduction so
that its effect is reduced
Contains alkali
metals
• Causes deposition of solids in
combustion applications including
boilers, engine and turbines. In turbines
the damage potential is considerable
particularly in high performance
• Hot vapour filtration
• Processing or upgrading of oil
• Pretreat feedstock to remove ash
Low pH • Corrosion of vessels and pipe • Careful materials selection;
stainless steel and some olefin
polymers are acceptable

Incompatibility with some
polymers
• Swelling of destruction of sealing rings and
gaskets
• Careful material selection
High temperature sensitivity • Liquid decomposition and polymerization
on hot surfaces leading to decomposition
and blockage; adhesion of droplets on
surface below 400°C
• Recognition of problems and
appropriate cooling facilities
• Avoidance of contact with hot
surfaces (< 500°C)
High viscosity • High pressure drops in pipelines leading to
higher cost equipment and/or possibilities of
leakage or even pipe rupture
• Higher pumping costs
• Careful low temp heating
and/or addition of water and/or
addition of co-solvents, such as
methanol or ethanol
Water content • Complex effect on viscosity
• Lowers heating value, density, stability, pH,
homogeneity, etc
• Can lead to phase separation
• Recognition of problem
• Optimization with respect to
application
In homogenity • Layering or partial separation of phases
• Filtration problems
• Blending with methanol or
ethanol

Property Cause Effect
High water content (30-
40%)
Pyrolysis reactions, inbound
moisture
Phase separation, lower heating value, corrosion, emulsion
formation, ignition delay in burners, increases pH
Phase Separation High moisture content, ash,
chemical composition
Layers formation, poor mixing, inconsistency in handling,
storage and processing
High oxygen content High O/C ratio Poor stability ( chemically and thermally), non miscibility
with hydrocarbons, acidity
High Viscosity Polymerization reaction High pumping cost, gives high pressure drop, Poor
atomisation.
High acidity or Low pH Organic acids Corrosion of the vessels and pipe work
Solids Particulates from reactor such
as sand and feed
contamination.
Sedimentation, erosion and corrosion, blockage
IMPORTANT PROPERTIES AFFECTING BIO-OIL QUALITY

Pilot scale pyrolytic reactor : 3 kg
Temperature : 400-550°C
Height and diameter of the reactor : 35 cm & 25 cm
Motor : 1.5 hp
Oil Yield : 55.5
TNAU PILOT SCALE PYROLYTIC REACTOR

Fluidized bed reactor : 10 kg h-1
Temperature : 400-525°C with 25°C
increment
Minimum fluidization velocity
of biomass
: 0.02 m s-1
Height and diameter of the
reactor
: 1.3 and 0.20 m
Inert gas supply plate : 0.20 m
Height and diameter of the
cyclone
: 0.80 and 0.20 m
Length of the condenser : 2.3 and 15 m
Motor : 1.5 hp
Oil Yield : 45 to 65 %
TNAU FLUIDIZED BED PYROLZER

Capacity : 1 kg h-1
HDPE:
oil yield : 86.28 %
solid residue yield : 4.72 %
Gas yield : 9.00 %
LDPE :
Oil yield : 87.02 %
Solid residue : 5.62 %
Gas yield : 7.36 %
PP wastes:
Oil yield : 89.34 %
Solid residue : 2.74 %
Gas yield : 7.92 %
PILOT SCALE PYROLZER FOR FUEL OIL
PRODUCTION FROM PLASTIC WASTES

TNAU HTL REACTOR
Capacity : 5 L
Temperature : 200 to 375°C
Pressure : Upto 20 MPa
Oil Yield : 60 %
AQUEOUS
CO-PRODUCT
BIOCRUDE
CHAR

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