Biomass Pyrolysis By Dr. Titiladunayo

Report
DEVELOPMENT OF A BIOMASS PYROLYSIS
REACTOR AND CHARACTERISATION OF
ITS PRODUCTS FOR INDUSTRIAL
APPLICATIONS
Department of Mechanical Engineering
The Federal University of Technology Akure.
Ondo State. Nigeria
JANUARY, 2012
Introduction



It comprises:- aggregate of all biologically
produced matter inform of:
wood and wood wastes;
 agricultural crops and their waste by-products;
municipal solid wastes;
animal wastes;
wastes from food processing;
and aquatic plants including sea weeds and algae
(Agarwal and Agarwal, 1999; U.S Dept of Energy,
2003).
Biomass is cheap, available, affordable and reliable
It’s a regular source of rural energy in Nigeria, fuel
wood is cheap, easily accessed by both rural &
urban dwellers.
2
– renewable, available,
and abundant on earth.
It is a versatile energy and
chemical resource
It
could be converted into
renewable products that could
significantly supplement the
energy needs of society
Biomass
3
Introduction Cont.--Globally, 140 billion metric tons of biomass is
generated every year from agriculture.
 This volume of biomass can be converted to an
enormous amount of energy and raw materials,
equivalent to approximately 50 billion tons of oil.
 Agricultural biomass waste converted to energy can
substantially displace fossil fuel, reduce emissions of
greenhouse gases and provide renewable energy to
some 1.6 billion people in developing countries,
which still lack access to electricity.
 As raw materials, biomass wastes have attractive
potentials for large-scale industries and communitylevel enterprises (UNEP 2009).

4
Biomass Resource & Availability
Wood Cuttings (1)
Wood Cuttings (2)
1
2
Wood Wastes
3
4
Wood Dust
Fig.1:Forest Biomass
5
Biomass Resource & Availability Cont...
Municipal Solid Wastes (MSW): generation is
enormous in our society.
 The expanding urban centres in Nigeria
have tremendous production of solid wastes
that could be utilized for energy through
different conversion routes. Garbage wastes
due to human & animal activities are
massive
 Lagos with 18 million inhabitants generates
about 9,000 metric tons of municipal solid
waste daily (0.5 kg/person/day), 80 percent
of this waste can be reconverted (LAWMA,
2010). Ibadan: 0.37–0.5 kg/person/day
6
(Maclaren International Ltd, 1970)

Fig.2:
Ojota dumpsite, Lagos, Nigeria. (Courtesy: LAWMA, 2010)
7
MSW - Material Distribution

Composition of MSW – Variable
50% Lignocellulosic Mat.(Wood, paper etc)
– 15% synthetic polymer based materialsPolyethylene (PE), Polypropylene (PP) and
Polyvinylchloride (PVC)
– 20% inorganic materials (metals, glass etc)
– 15% others (Blasi, 1997)
 Natural Decomposition- May affect environment &
climate change
 Recycling waste for energy and chemicals
products will consume waste and safe the
environment
–
8
Straws and Grasses for Energy
Miscanthus
9
Rice Straw
Fig.3: Straw and Grasses
Wood composition
Cellulose content
Lignin content
Extractives content
Fibre length
Coarseness
Softwood
42% +/- 2%
28% +/- 3%
3% +/- 2%
2-6 mm
15-35 mg/100 mm
Hardwood
45% +/- 2%
20% +/- 4%
5% +/- 3%
0.6-1.5 mm
5-10 mg/100m
Cellulose and hemi-cellulose contain only around
17.5 MJ/kg high heating values (HHV) while
lignin has about 26.5 MJ/kg HHV and extractives
can approach 35 MJ/kg HHV
(Ramachandra and Kamakshi, 2005; NC State, 1993
10
Polymeric Constituent of woody Biomass
1.
2
3
Cellulose (C6H10O5)n
•Structure, fibre walls
•Carbohydrate (sugar)
•Polymer of glucose C6H10O6
Hemicellulose(C5H8O4)n
•Encasing of cellulose fibre
•Carbohydrate
•Other than glucose
•Dissolvable
Lignin (C40H44O6)
•Binding agent / strength
•Non-sugar polymer
•Aromatic structure
11
Biomass Conversion Routes
Biomass
Biochemical
Conversion
Screening,
Pretreatments,
Fermentation,
Filtration,
Distillation,
Effluent treatment
12
Thermochemical
Conversion
Slow Pyrolysis
(Carbonisation),
Fast pyrolysis,
Flash Pyrolysis,
Ablative
Pyrolysis,
Gasification.
Particle size Preparation

Process: Chipping, grinding and milling to
reduce particle size.
–
–

13
Materials size after chipping
Size after milling or grinding
10–30 mm
0.2–2 mm.
Type of milling M/C:
(i) Vibratory ball milling
(ii) Ball milling (Millet et al.,1976)
Biochemical biomass Conversion







14
Fermentation is the biochemical route of converting
sugar, starch or hydrolysed lignocellulosic biomass to
ethanol (alcohol) in a process similar to anaerobic
respiration
Milling to an optimum size to facilitate effective
pretreatment.
Pretreatment to facilitate effective Hydrolysis and
fermentation.
Hydrolysis - conversion of cellulose to sugars
Fermentation of sugars to bioethanol.
Filtration and/or distillation to remove the byproducts
from the bioethanol.
Management of Waste by-product.
15
Biomass Energy Conversion Routes:
Direct Combustion: Exothermic reaction of
biomass combustible elements with
Oxygen.
 Biomass locked-up energy is released by
burning.

The combustible elemental composition of
biomass is completely oxidized to H2O & CO2
with the release of heat and light (FAO, 1987).
► requires adequate air supply;

16
THE PYROLYSIS PROCESS:
 Carbonisation: Upgrades biomass energy
to high dense energy fractions in a
quiescence environment
 The three major biomass polymer building
blocks degrades to charcoal, pyroligneous
liquor and syngas

17
Process is influenced: heating rate, residence
time, particle size, chemical composition,
moisture content and final pyrolysis temp. of the
wood feedstock.
Effect of temperature on biomass
At a temperature less than 260ºC Charring of
biomass feedstock occurs
Between 275ºC and 400ºC depolymerisation of
chemical components generally predominates
Between 200ºC and 280ºC hemicellulose is
converted to methanol and acetic acid
Above 280 ºC lignin decomposes to produce tar
and charcoal (Hillis, 1975; Bailey and
Blankehorn, 1982; Fuwape, 1996).
18
HEAT
Biomass
HEAT
Cellulose
Pyro-oil (methanol + Acetone+ Acetic Acid + Tar +
etc), + Pyrogas (CO + CO2+ CH4+ H2 + unburnt
19 hydrocarbons), + Char
Economic Advantage of Biomass Energy
Utilizing forest residues, mill residues, logging
residues and various wood cuttings for
charcoal production will go a long way to boost
domestic and industrial energy resources,
thereby reduce pressure on the forest.
 Inexhaustible production of renewable fuel &
chemicals is guaranteed
 It improves the environment, as waste is
consumed & the effect of Methane is mitigated
 Wood conversion to charcoal is a process
involving the thermal separation of its volatile
constituent from the char residue.

20
Economic Advantage of Biomass Energy




21
Charcoal is a high-grade fuel having a heating value of
28.7-34 MJ/kg compared to wood of 20-26.5 MJ/kg
(Fuwape, 1996).
Charcoal is easier to handle than the parent stock,
Fuel for household and industrial settings (metal extraction
in iron smelting, generating producer gas, serves as
activated carbon particles for water treatment systems)
(FAO, 1985).
Pyroligneous oil is used as fuel oil substitute, chemical
sources, solvent and insecticide
Industrial Utilization of Charcoal





22
Chemical Industries - manufacture of carbon
disulphide, sodium cyanide and carbides, ethanol,
methanol, Acetic acid, etc
Iron Smelting - smelting and sintering iron ores,
production of ferro-silicon and pure silicon, case
hardening of steel, etc
Fuels - fuels in foundry, cupolas, electrodes in
metallurgical industries, etc
Water and Gas Purification - dechlorination, gas
purification, solvent recovery; waste water treatment,
etc
Gas Generator - In the production of producer gas
for vehicles and carbonation of soft drinks.
Charcoal as fuel for industry
The advantages of charcoal depend on six
significant properties which account for its
continued use as fuel in industry.
 relatively few and unreactive inorganic
impurities
 stable pore structure with high surface area
 low sulphur content
 high ratio of carbon to ash
 good reduction ability
23 almost smokeless

Pyroligneous Liquor




Crude condensate consists mainly of water and
non-water component:
Crude bio-oil is dark brown and approximates to
biomass in elemental composition.
It is composed of a very complex mixture of
oxygenated hydrocarbons with an appreciable
proportion of water from both the original moisture
and reaction product. Solid char may also be
present.
The liquid has a distinctive odour - an acrid smoky
smell, which can irritate the eyes if exposed for a
prolonged period to the liquids. The cause of this smell is
due to the low molecular weight aldehydes and acids.
24
Properties of Pyrolysis oil
(i) Oxygen content
35 – 50 wt%
 (ii) Identified
300compounds
 (iii) Water Content
15 – 30wt%
 (iv) LHV
14 -18 MJ/kg
 (v) Density (ρ)
1.15 – 1.25 kg/dm3
 (vi) pH-value
2-3
 (vii)Molecular Weight
370 - 1000g/mol
 (viii) Volatility
Boiling Start 100°C
Residues left (5-50 %) Stop 250-280°C

(Czernik & Bridgwater, 2004; Oasmaa& Stefan, 1999)
25
Non- Condensable gas (Syngas)
Wood gas is useable as fuel
 It consists typically of:








17% methane;
2% hydrogen;
23% carbon monoxide;
38% carbon dioxide;
2% oxygen
and 18% nitrogen.
It has a gross calorific value of about 10.8
MJ/m³ (290 BTU/cu.ft.) i.e. about one third
the value of natural gas.
Source: FAO (1985)
26
Inorganic Constituents of Ash

Ash is a good source of calcium,
potassium,
phosphorus,
magnesium,
Sodium, Iron, Zinc, silicon, Copper and
aluminium.

Ash from woody biomass, in general, stimulates
microbial activities and mineralization in the soil
by improving both the soil's physical and
chemical properties (Soil amendment).
Wood ash neutralizes soil acidification caused
by whole-tree harvesting as well as acid
depositions (raise the pH of acidic soils)

27
A pyrolysis plant is developed to produce
higher dense energy products from
renewable
biomass
through
thermochemical conversion processes.
 The plant does not produce useful energy
directly.
 More convenient high grade energy &
chemical products, are produced under
regulated heat load and restricted air
supply.

28
Slow and Fast Pyrolysis
Temperature = Low/Moderate
 Heating Rate = Low/High
 Carrier gas = Not required/ Required
 Material Residence time = Long/short
 Vapor Residence time = Long/short
 Particle size = ≥ 10cm / ≤ 1mm
 Oil yield = Could be low/ High (70-80%)

29
Biomass Charcoal Production Techniques
Pit carbonisation method
 Kiln carbonisation method

This method is termed; charcoal burning, as
part of the wood charge is burnt to supply the
needed heat for the effective transformation of
the remaining wood charge to charcoal.
Pit Mound (Liberia)
FAO, 2008
Fig.4: Kilns
Beehive kilns (USA)
FAO, 2008
30
Retort Processes:
The retort process (destructive distillation of wood) came
into industrial use in the 18th and 19th century (Fapetu,
2000).
Heat for carbonisation in this process is externally supplied
to a closed vessel, which contains the woodchips to be
carbonised (FAO, 1987).
Volatiles are captured and collected through various cooling
or condensation devices.
Pyrolysis in the kiln and retort devices occur in three
notable phases: drying, pyrolysis, & cooling for the products
of biomass.
31
The retort principle
for carbonization
(FAO, 2008)
(A)
(B)
(C)
A continuous rotary retort
Lambiotte Retort (France)
32
Fig. 6: Charcoaling Retorts
33
Unzipping of Biomass polymer chain
Non–condensable
portion (syngas)
Residual
fractions:
Pyroligneous liquor
The char residues
(charcoal
34
Percentage charcoal yield decreases with
increasing carbonisation temperature.
The percentage yield of combustible
gases (Syngas) & pyroligneous liquor is a
function of:
carbonisation temperature
& degree of biomass polymerisation.
35
Justification (What has been done)





36
Several studies considered wood carbonisation from
150-550°C (Bailey & Blankehorn, 1982; Fuwape 1996;
Gommaa and Mohed, 2000; Shinya & Yukiwko, 2008).
Conversion of wood to charcoal is affected by the
heating rate, residence time, particle sizes, chemical
composition and moisture of the wood and the final
pyrolysis temp. (Fuwape 1996).
Traditional kilning techniques (yield charcoal usually in
the range of 5%-20% of the parent stock) &
Industrial / Modern retorting techniques(20%-30%)
(FAO, 2008).
Charcoal yield takes between 7-30 days in the
traditional kiln (Sanabria & Paz, 2001; SINTEF Energy
Research, 2010).
Need to investigate the effect of higher temperature on
lignocellulosic biomass than previously reported.
 Development of a pyrolysis plant with a comparative
edge at reducing carbonisation time, and improving
carbon yield at elevated temperatures.
 Most research work by authors; focused on temperate
wood species, a need therefore arises for the
physiochemical characterisation of tropical wood
species and their thermochemical by-products.
 The effectiveness of the pyrolysis plant at handling
variety of biomass species is investigated. The
relationship between biomass yield as a function of
the degree of biomass polymerisation and
37 temperature is established.

38

Development of an electrically fired,
fixed-bed reactor with electronics
accessories and equipped with a
pyrolysis furnace with selected
refractory lining.

Feedstock selection,
preparation

Experimentation, Documentation and
Data Analysis
sizing
and

Main objective: to develop biomass pyrolysis reactor
and characterise its products for industrial applications

Specific objectives:
develop a thermochemical reactor, for the conversion of
selected lignocellulosic biomass materials into high
grade energy and industrial products;
evaluate the effects of temperature on the degree of
carbonisation of the solid products;
determine the physio-chemical, thermo-chemical and
the gross energy characteristics of the selected biomass
and their derived fractions; and
assess their suitability for industrial applications.
39
 Selection
of appropriate refractory
materials for lining the furnace of
pyrolysis plant from four locations in
State: - Ikere Ekiti, Fagbohun Ekiti, Ishan
and Ara Ekiti.
40
Fig .7: Kaolin (China Clay)
clay
the
Ekiti
Ekiti
DEVELOPMENT OF THE REACTOR Cont….

Appropriate refractory clay selection as
furnace lining was based on:
Meeting known physical, chemical, and
refractory standards;
 Ability to withstand thermal shock & very
high operating temperature (1800°C)
without thermal deformation.
 Non-reactive characteristics with pyrolysis
products at elevated temperatures.
 Efficient thermal conservation

41
Table.3:Chemical Characteristics of Selected Clays
Mean and Standard Deviation of chemical Properties
S/No
1
2
Clay
Samples
A
B
3
C
4
D
%
%
%
%
%
%
%
%
%
%
%
Al2 SiO2 K2O CaO Ti2O MnO Fe2O MgO Na2O Cr2O LOI
O3
3
3
30.4 50.9 0.33± 0.19± 1.88± 0.01± 2.07± 0.13± 0.04± 0.02± 12.1
6±
2±
0.05d 0.01d 0.02d 0.01c 0.1d 0.02a 0.02c 0.01d 8±
d
d
0.89 2.12b
0.02a
a
c
18.7
5±
0.5b
13.4
8±
0.5c
10.9
2±
0.58
53.9
0±
3.55b
40.6
8±
1.72d
59.9
0±
3.94a
3.30± 0.72± 2.29± 0.03± 11.80
1.58a 0.03c 0.14c 0.02c .±
0.16b
2.88± 1.12± 2.68± 0.15± 25.5
0.19c 0.07b 0.15a 0.02b 5.±
b
0.02a
3.25± 1.90± 2.76± 0.19 11.40
0.09a 0.16a 0.02a ±0.02 ±
b
a
0.32c
0.13± 0.09± 0.04± 7.85±
0.01a 0.01b .00b 0.01d
c
0.10± 0.02± 0.06± 10.7
0.92a 0.01c 0.01a 8.±
b
d
0.01b
0.19± 0.12± 0.04± 7.98±
0.12a 0.03a 0.01b 0.01c
c
d
A = Ikere-Ekiti, B = Fagbohun - Ekiti, C = Ishan -Ekiti, D = Ara -Ekiti
Values in the same column with different alphabet are significantly different from each other.
(Result of Chemical test of Clays from selected sites in Ekiti State, Nigeria)
42
Physical Characteristics of Selected Clays
Table.4: Mean and Standard Deviation of the Physical
characteristic of the selected Clay
Sample
No
Sample
Name
Bulk
density
g.cm-3
Porosity
%
C.C.S.
kg / cm2
Shrinkage
Slag
Resistance
A
IKERE
1.74±0.11d
31.44±0.91a
100±6.21c
5.0±1.23a
Good
B
FAGBOHUN
2.0±0.15a
20.69±1.01bc
140±6.44b
2.0±.00b
Good
C
ISHAN
2.0±0.02ab
19.10±0.19d
227±12.9a
1.50±0.16bd
Poor
D
ARA
1.99±0.01ac
23.31±0.24b
83±3.24d
1.9±0.1bc
Poor
A = Ikere-Ekiti, B = Fagbohun - Ekiti, C = Ishan -Ekiti, D = Ara –Ekiti
Values in the same column with different alphabet are significantly different from
each other.
43
Table 5 : Result of Refractoriness test on selected Clays
Sample
No
Sample
Name
Refractoriness
Seger
PCE No.
A
B
C
D
44
Ikere
Fagbohun
Ishan
Ara
Cone 29
Cone 16
Cone 10
Cone 10
Range /
Limit
>
<
<
<
Pyrometric Cone
Equivalent (PCE)
Temperature
1500°C
1500°C
1300°C
1300°C
High PCE
Intermediate PCE
Low duty PCE
Low duty PCE



45
The densities (ρClay) of the clay materials are
functions of the major constituents of the
(alumino-silicate ) refractory clay samples
Porosity is also a function of density
Bulk density is highly significant in predicting
the apparent porosity of the clay samples: R2
= 0.97889
REACTOR COMPONENTS
The reactor : -Electrically–fired Furnace chamber
-An airtight crucible (Fixed-Bed)
-Control Box (With digital readout)
- Step-down transformer
- Counter-flow Liebig condenser
- Pyro-oil traps
- Gas displacement vessel
- Cooling water circulation pump
46
THE FURNACE
Developed from locally available materials
 Wall thickness was determined using:

–
–
–
Appropriate heat transfer design tools in furnaces
Thermo-chemical and refractory properties of kaolin and
the maximum designed furnace temperature
Heating rate was achieved by regulating the input voltage
from the circuit’s transformer.
 Resistance
47
(R1 and R2) of two heater
elements connected in parallel, which is the
equivalent resistance of the electrical
connection in Fig (1) and (2).
HEAT INPUT
R1
V
V
RR
R22
V
Req
V
FIG. 8: Resistance Elements Connected in Parallel
48
HEAT INPUT Contd

Q  f (V , Req )
(1)
Req  f (R1 , R2 )
(2)
V2
Q
(W )
Req
(3)
R1 R2
Rrq 
R1  R2
(4)
The total energy (Q) supplied to the furnace is obtained by
substituting equation (4) into (3)
2 R1  R2
Q V .
(5)
R1 R2
49
Ceramic wall
Fig.9 : Furnace Wall
Heat conduction through the furnace wall is obtained by applying
the general heat conduction equation in cylindrical coordinate
(Rajput, 2007; Yunus, 2002).
50
2
  2 1 t 1 t
t
 2  .  2 . 2 . 2
z
 r r r r 
 qg
1 t
 .

 
 k
(6)
Where:; r  Out side radius of furnace, φ,&Z  Coordinat eaxis for heatflow,
k  T hermalconducct ivit y,
q g  Uniformvolumet richeatgenerat ion per unit volumeper unit t ime.
For steady state
t  f ( , z ), t
 f ( , z)
for heat flow in
radial direction and q g  0 with no heat generation and
equation (6) reduces to
  2 1 t 
 2 .
 0
r r 
 r
51
( 7)


Integrating equation (7) with boundary conditions of t
= t1; at r = r1 and t = t2; at r = r2 the value for
temperature distribution‘t’ within the furnace wall
becomes:
(8)
t1  t 2
t1  t 2
t  t1 
ln (r1 ) 
ln( r )
lnr2 r1 
lnr2 r1 
Heat transfer rate is obtained by substituting equation (8) in
Fourier’s equation (9) to give equation (10):
dt
Q   kA
dr
52
(9)

d
t1  t2
t1  t2
Q   kA t1 
ln (r1 ) 
ln(r )
dr  lnr2 r1 
lnr2 r1 


(t1  t 2 )
ln (r2 r1 )
2kL
By integrating equation Q 
(10)
(10)
(11)
The Furnace appropriate wall thickness was obtained by
substituting equation (5) in (11):
(t 1  t 2 )
ln (r2 r1 )
2kL
53
R1  R2
 V .
R1 R2
2
(12)
Integrating equation (7) with boundary conditions of t = t1; at r = r1 and t = t2;
at
r = r2 the value for temperature distribution ‘t’ within the furnace wall becomes:
t  t1 
t1  t 2
t  t2
ln (r1 )  1
ln( r )
lnr2 r1 
lnr2 r1 
(8)
Heat transfer rate is obtained by substituting equation (8) in Fourier’s equation
(9) to give equation (10):
Q   kA
Q 
dt
dr

d 
t1  t2
t1  t2
 kA t1 
ln (r1 ) 
ln( r )
dr 
lnr2 r1 
lnr2 r1 

By integrating equation (10)
54
(9)
(t1  t2 )
Q 
ln(r2 r1 )
2kL
(10)
(11)
The Furnace appropriate wall thickness was obtained by
substituting equation (5) in (11):
(t 1  t 2 )
ln(r2 r1 )
2kL

R1  R2
V .
R1 R2
2
(12)
DETERMINATION OF THE APPROPRIATE
FURNACE WALL THICKNESS:
By integrating equation (12) Furnace appropriate wall thickness is
determined to be:
r2  r1  r1 ( e
55
2 kL (T1  T2 ).
Req
V2
 1)
(13)
Furnace is shown in Figure (10) Figure(7)
Fig.10: Reactor’s sections & Modeling
56
Fig. 11 THERMAL REACTOR
SECTION A-A
57
DEVELOPMENT OF THE FURNACE Cont...
58
FIG. 12: Furnace with Cover
DEVELOPMENT OF THE FURNACE Cont…
59
FIG. 13: Furnace Showing Resistance
Elements
DESIGN OF BRASS CRUCIBLE:
The brass crucible is made of 0.015 m brass plate rolled into an
enclosed cylinder and designed to hold averagely about 0.8 - 1.0 kg of
the selected biomass samples for carbonisation at a time in the
designed furnace. Length (L) of the crucible is assumed but the
densities of the various biomass feedstock ( 1 ,  2 , 3 ) were used to
determined the volume of the crucible after experimentation.
Average density (
) =
n 1
n
f (1 ,  2 , 3 ) = 
n
n 1
(1 4)
n 1
Average mass (
m)= f
mn
( m1 , m2 , m3) = 
n
Volume of cylindrical crucible (
60
v
)=
r L
2
c
n 1
(1 5)
(17)
Combining equations 14, 15 and 16 the radius of the
crucible is determined by equation (17)


rc 
m
V
(17)
m
L
(18)
The furnace completely envelopes the crucible and supplies its pyrolysis heat
through an electrical resistance heater. Heat diffusion to the crucible from the
inner surface of the furnace is assumed to have taken place by conduction,
since the environment is assumed quiescent and the space between them
negligibly small.
Heat flux (Q) across the crucible could be analysed by the following equation:
Qc
61

 2k (Tc  T1 )
r
ln 0
rc
(19)
BRASS CRUCIBLE
62
FIG. 14: The Fixed- Bed Reactor’s Crucible
DEVELOPMENT OF THE FURNACE Cont…
63
FIG. 15: Furnace and Reactor
Design of Automatic Control Box

Automatic Control Box: Heat input regulation
and temperature / residence time control were
achieved through the operation of the designed
Automatic Control Box shown on Figure 10 (a
& b).
64
Design of Automatic Control Box
Fig .16 A: Control Box Wiring Diagram
65
66
FIG. 16 (B): Automatic Control Box
67
FIG. 16 (C): Automatic Control Box (Opened)
Feedstock selection, sizing and preparation
Materials Sizing: 10 kg each of Apa wood (A.
africana), and Iroko wood (M. excelsa) were
processed into fine rectangular pin chip particles
size of 10 x 10 x 60 mm
 while Palm kernel shell (E. guineensis), was
processed by sieving and utilised as received
 Moisture removal The materials were subjected to
moisture removal in the oven using ASTM: E 871 82 (ASTM 2006) at 103±2°C for 24 hours and until
constant weight was attained per sample after
three consecutive measurements.

68
Feedstock selection, sizing and preparation

The free moisture in the samples was therefore
completely removed by this process, making them
to attain identical moisture free platform. The
average moisture totally expelled from the 20
batches per material sample (%) was determined
using equation (20).

Total expelled moisture content (% wt/wt) =
(20)
69
Selected Feedstock Species
(A)
M. excelsa
(B)
A. africana
(C)
E. guineensis
Fig. 17: Sizing of Selected Feedstock for Pyrolysis Experiments
70
Experimentation and Documentation


71
Carbonisation experiments were carried out
at various elevated temperatures for all
samples in the developed electrically fired
‘Fixed-Bed Reactor’ at pre-determined
temps., ranging from 400°C to 800°C and at
100°C intervals.
Fifteen batches (0.5 kg net weight per batch)
each of the selected materials of constant
moisture content were used as feedstock in 3
replicated experiments
Experimentation & Documentation Cont…

By-products of pyrolysis:
 charcoal (solid fuel),
 oils (liquid fuel),
 and pyrogas (non-condensable gaseous products).


72
Experiments were conducted under a quiescent
environment (insufficient or complete absence
of air).
Feedstock residence time, furnace temp. and
pyrolysis (reaction) temp. were recorded as
displayed on the controllers and recorded every
5 min.
Experimental Set-up
Fig. 18: Pyrolysis Experimental set-up
73
Assembling the Fixed-Bed Reactor
74
Fig.19 Assembling the reactor for an Experiment
Fig. 20: Fully Assembled Fixed-Bed Reactor with an
Ongoing Experiment
75
Exp., Result, Discussion & Analysis

76
To be continued on Friday (01-27-2012)
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YOU
FOR
LISTENING
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77

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