BIOCHAR PRODUCTION BY
PYROLYSIS OF LIGNOCELLULOSIC
BIOMASS IN A CONICAL SPOUTED
BED REACTOR
Maider Amutio, Gartzen Lopez, Maite Artetxe, Astrid Barona, Martin Olazar
Chemical Engineering Department, University of the Basque Country UPV/EHU
PO Box 644 – 48080 Bilbao. Spain. martin.olazar@ehu.es
eman ta zabal
zazu
Universidad
del País Vasco
Euskal Herriko
Unibertsitatea
Introduction
 Biomass
o Alternative to fossil fuels → the only renewable source of fixed carbon.
o Biomass → Liquid, solid and gaseous fuels + heat and power.
 Pyrolysis
o One of the technologies with the best industrial perspectives.
o Bio-oil as biorefinery feedstock (decouple bio-oil production).
 Biomass flash pyrolysis
T ~ 500 ºC
o Maximum liquid production: Very high heating rates
Short gas residence time
Rapid char removal
Minimize
secondary
cracking
reactions
o Products: Bio-oil = 60-80 wt%. Alternative fuel or source of chemicals
Gas = 10-20 wt%. Supply energy to the pyrolysis plant
Char = 15-25 wt%. Fuel, activated carbon or soil amendment.
Chemical Engineering Department. University of the Basque Country
PO Box 644 – 48080 Bilbao. www.ehu.es/cpwv
Introduction
 Vacuum pyrolysis
o Improvement of the operational capacity of this technology:
• Reduction of the mass flow-rate of the inert gas→ reduction in the energy
requirement to heat the gas to the reaction temperature.
• Simplification of the bio-oil condensation and collection section.
o Advantages:
• Reduction of secondary cracking reactions: rapid desorption and extraction
of the volatile products from the reaction environment.
• Improvement in char quality.
 Reactors
o Biomass flash pyrolysis: Fluidized bed reactors.
o Biomass vacuum pyrolysis: Vacuum moving bed.
Chemical Engineering Department. University of the Basque Country
PO Box 644 – 48080 Bilbao. www.ehu.es/cpwv
Introduction
 Conical spouted bed reactor (CSBR)
Advantages:
o Simple design
o Less pressure drop than fluid beds
Fountain
Spout
o Different particle diameters and
irregular materials
o Great versatility in gas flow (low
Annulus
residence time)
o Good heat and mass transfer
o Allows continuous extraction of char
Chemical Engineering Department. University of the Basque Country
PO Box 644 – 48080 Bilbao. www.ehu.es/cpwv
Introduction
 Conical spouted bed reactor
(CSBR)
Advantages:
o Simple design
o Less pressure drop than fluid beds
o Different particle diameters and
irregular materials
o Great versatility in gas flow (low
Annulus
residence time)
o Good heat and mass transfer
o Allows continuous extraction of char
Chemical Engineering Department. University of the Basque Country
PO Box 644 – 48080 Bilbao. www.ehu.es/cpwv
Experimental
 Pyrolysis bench scale plant
Chemical Engineering Department. University of the Basque Country
PO Box 644 – 48080 Bilbao. www.ehu.es/cpwv
Experimental
 Raw material: Pinewood (pinus insignis) sawdust
 Experimental conditions
o
o
o
o
o
Temperature: 400 and 500 ºC
Pressure: 0.25 and 1 atm
Biomass: 0.1-2 mm, 25 kg/min
Bed: 20 kg sand (1-2 mm)
Inert gas flow rate (liters/s)
Pressure (atm)
Temperature (ºC)
400
0.25
1
3.2
11.5
500
3
10.5
o On line product analysis: GC, µGC and GC/MS
Chemical Engineering Department. University of the Basque Country
PO Box 644 – 48080 Bilbao. www.ehu.es/cpwv
Experimental
Chemical Engineering Department. University of the Basque Country
PO Box 644 – 48080 Bilbao. www.ehu.es/cpwv
Experimental
Chemical Engineering Department. University of the Basque Country
PO Box 644 – 48080 Bilbao. www.ehu.es/cpwv
Results: product yields
 Fractions: gas, bio-oil and char. Yields in wet basis
80
400 ºC
0.25 atm
1 atm
60
70
Yield (%wt)
Yield (%wt)
70
80
50
40
50
40
30
20
20
10
10
0
0
o
o
o
Bio-oil
Char
0.25 atm
1 atm
60
30
Gas
500 ºC
Gas
Bio-oil
Char
High liquid yields: 77 % wt at 500 ºC and 0.25 atm
P ↓ → bio-oil ↑, char ↓ (reduction of secondary reactions)
P ↓ → Desorption and diffusion of the volatiles in the biomass particle ↑
Residence time of volatiles in the particle ↓
Chemical Engineering Department. University of the Basque Country
PO Box 644 – 48080 Bilbao. www.ehu.es/cpwv
Results: gas composition
 Mainly made up of CO2 and CO
 P ↓ → CO2 ↑, T ↑→ CO2 ↓
Compound
CO2
CO
H2
CH4
ethylene
ethane
propylene
propane
2-methyl-1-propene
2-butene
unidentified
Gas
400 ºC
0.25 atm
5.08
2.49
0.01
0.06
0.02
0.01
0.02
0.01
0.00
7.7
1 atm
4.36
2.42
0.05
0.01
0.01
0.01
0.01
0.01
0.00
6.9
500 ºC
0.25 atm
3.47
3.34
0.01
0.32
0.10
0.04
0.11
0.02
0.04
0.03
0.04
7.5
1 atm
3.27
3.38
0.00
0.36
0.09
0.06
0.07
0.05
0.02
0.01
0.01
7.3
Chemical Engineering Department. University of the Basque Country
PO Box 644 – 48080 Bilbao. www.ehu.es/cpwv
Results: bio-oil composition
Compound
acids
aldehydes
alcohols
ketones
phenols
alkyl phenols
catechols
guaiacols
furans
saccharides
levoglucosane
others
unidentified
water
Bio-oil
400 ºC
0.25 atm
3.32
2.41
2.26
6.79
16.35
3.04
2.94
10.37
2.58
3.55
0.22
0.14
11.95
23.00
73.01
1 atm
2.49
2.44
1.75
5.87
15.57
2.12
3.15
9.94
3.30
5.26
0.52
0.09
10.70
23.33
71.23
500 ºC
0.25 atm
2.40
2.37
1.56
5.81
18.75
1.18
10.09
7.48
1.63
6.26
3.27
0.03
13.41
24.98
75.33
1 atm
2.73
1.93
2.00
6.37
16.49
1.80
7.16
7.53
3.32
4.46
2.78
0.06
12.61
25.36
77.19
 Water is the main
compound ~ 25 %wt
 Phenols: guaiacols
(methoxy phenols),
catechols (benzenediols)
and alkyl-phenols.
 Saccharides:
levoglucosan yield
increases at lower
pressures.
 Pressure has different
influence at 400 ºC and
500 ºC
 P ↓→ Bio-oil is
composed of heavier
compounds
Chemical Engineering Department. University of the Basque Country
PO Box 644 – 48080 Bilbao. www.ehu.es/cpwv
Results: bio-oil properties
 P ↓→ Carbon content increases slightly (less water and more heavier and less
oxygenated compounds) → Calorific value ↑
 Operating at subatmospheric pressure slightly improves bio-oil’s valorization
prospects as fuel. However, its calorific value is low, so it has to be subjected to
treatments.
Properties
Ultimate analysis (% wt)
carbon
hydrogen
nitrogen
oxygen
Water content (% wt)
Calorific value (MJ/kg)
400 ºC
0.25 atm
1 atm
43.9
8.1
0.1
47.9
34.5
15.8
42.7
8.1
0.1
49.1
35.8
15.2
500 ºC
0.25 atm
1 atm
42.9
8.0
0.2
48.9
35.3
15.4
Chemical Engineering Department. University of the Basque Country
PO Box 644 – 48080 Bilbao. www.ehu.es/cpwv
41.7
8.1
0.2
50.0
36.7
14.6
Results: char characterization




T ↑→ Carbon content and calorific value ↑
P ↓ → Carbon content and calorific value ↑ at 400 ºC but ↓ at 500 ºC.
Carbon content > 75 % . Low ash content
LHV higher than the ones of soft coal (29 MJ/kg) and lignite (20 MJ/kg)
400 ºC
0.25 atm
1 atm
Ultimate analysis (wt%)
Carbon
Hydrogen
Nitrogen
Oxygen
Proximate analysis (wt%)
Volatile matter
Fixed carbon
Ash
LHV (MJ kg-1)
500 ºC
0.25 atm
1 atm
79.7
3.4
0.01
16.9
75.0
3.8
0.2
21.0
84.5
2.8
0.1
12.6
85.2
3.0
0.1
11.8
27.6
69.8
2.6
26.8
37.6
60.2
2.2
21.6
24.0
72.8
3.2
28.2
23.5
73.6
2.9
30.4
Chemical Engineering Department. University of the Basque Country
PO Box 644 – 48080 Bilbao. www.ehu.es/cpwv
Results: char characterization
 P ↓ → BET surface area ↑, pore diameter ↓
 500 ºC, 0.25 atm → mesopores of 100 Å and micropores of 19 Å are formed
 Devolatilization and diffusion of volatiles through the biomass particle ↑
Blocking of the pores due to carbonaceous material deposits ↓
400 ºC
0.25 atm
1 atm
Surface characteristics
BET surface (m2 g-1)
Average pore diameter (Å)
5.1
464.3
1.9
472.1
500 ºC
0.25 atm
1 atm
79.2
53.2
500 ºC, 0.25 atm
Chemical Engineering Department. University of the Basque Country
PO Box 644 – 48080 Bilbao. www.ehu.es/cpwv
16.2
453.5
500 ºC, 1atm
Conclusions
 Conical spouted bed reactor: suitable technology to perform
vacuum biomass flash pyrolysis.
 High bio-oil yields: 77 wt% at 500 ºC and 0.25 atm.
 Vacuum influence on product yields and properties:
o Low influence on fraction yields, but bio-oil yield slightly
increases.
o Bio-oil: heavier compounds (phenols, levoglucosan, etc.), less
water. Calorific value ↑
o Char: Improvement of surface characteristics.
 Vacuum increases process viability: Inert gas flow rate is lower →
Less energy is required to heat the carrier gas and the condensation
of the product stream is easier.
Chemical Engineering Department. University of the Basque Country
PO Box 644 – 48080 Bilbao. www.ehu.es/cpwv
BIOCHAR PRODUCTION BY
PYROLYSIS OF LIGNOCELLULOSIC
BIOMASS IN A CONICAL SPOUTED
BED REACTOR
Maider Amutio, Gartzen Lopez, Maite Artetxe, Astrid Barona, Martin Olazar
Chemical Engineering Department, University of the Basque Country UPV/EHU
PO Box 644 – 48080 Bilbao. Spain. martin.olazar@ehu.es
eman ta zabal
zazu
Universidad
del País Vasco
Euskal Herriko
Unibertsitatea