Biokenaf project
thermochemical conversion tests
Progress meeting in Catania, July 2005
Douwe van den Berg
BTG biomass technology group bv
vandenBerg@btgworld.com
Overview of presentation
> Introduction thermal conversion processes
> Feeding of core and whole plant material
> Ash behaviour
> Gasification experiments
> Combustion experiments
> Pyrolysis experiments
slide 2
Introduction
Bio-energy conversion chain
biomass
pre treatment
conversion
product
- sizing
- woody
- compacting
- sugar c.
- drying
- oil cont.
- sieving
- herbacious
- transport
- thermal
- fysical
- biochemical
- heat
- electricity
- fuel
- storage
- etc.
Specification
slide 3
Introduction
Overview conversion-technologies
Gasification
Combustion
Hot
water
Steam
Steamturbine
Heat
slide 4
Pyrolysis
Gas
Oil
Gasturbine
Electricity
Carbon
Gasmotor
Digestion
Fermentation
Extraction
Destillation
Esterification
Biogas
Bioethanol
PVO
Transportfuel
Biodiesel
Introduction
Biomass technology combinations
> “dry” biomass
– combustion, gasification, pyrolysis
> “wet” biomass
– (co-)digestion
– new technologies (HTU, SCW)
> oil and fat
– combustion, gasification, (co-)digestion
> oil containing crops
– extraction and esterification
> sugar and starch containing crops
– fermentation
slide 5
Introduction
Capacities
Scale of production
digestion
electricity
heat
gasification
combustion
0.01
0.1
1
10
capacity (MW)
slide 6
100
1000
Introduction
State of the art
carbonisation
combustion
esterification
fermentation
digestion
gasification
pyrolysis
HTU
supercritical
development
slide 7
demonstration
commercial
Introduction
Thermochemical conversion
biomass (CH1.4O0.6)
combustion
(excess O2)
(sub stochiometric O2)
CO2 + H2O
CO + H2 + CO2
slide 8
gasification
pyrolysis
(without O2)
char (solid)
pyrolysis oil (liquid)
non condensibles (gas)
Introduction
Combustion - example
biomass-plant Lelystad The Netherlands (NUON)
–
–
–
–
–
slide 9
capacity: 1,7 MW electric + 6,5 MW thermal
thinnings, energy crops, 25.000 ton45/a
fixed bed combustion with steamcycle
ηel ≈ 16%, ηth ≈ 66%, ηtot ≈ 82%
investment ca. 6.900 €/kWe
Introduction
Gasification - example
biomass-gasifier Güssing (Oostenrijk) - 2001
–
–
–
–
–
slide 10
capacity: 2 MW electric, 4,5 MW thermal
wood chips
fluidised bed gasifier with gas motor
ηel ≈ 25%, ηtot ≈ 80%
total costs ca 9 M€
Introduction
Pyrolysis - example
> BTG 2 t/hr commercial plant under construction in Malaysia
> Bio-oil for co-combustion in power plants
> Research is being carried out to upgrade bio-oil to transport
fuel by water removal and hydrotreating.
slide 11
Feeding
Kenaf samples
> Samples received April 2005
> “whole plant”
– 2004 harvest from CETA
– chipped and dried under roof
> “core material”
– 2005 harvest from CETA
– seperated by KEFI
slide 12
Feeding
Kenaf properties and preparation
Core
Milling
Whole plant
slide 13
Feeding
Kenaf properties and preparation
> Bulk density
> Particle size and size distribution
> Flow properties
Bulk density
[kg/m3]
Core
Whole plant
Whole plant milling
slide 14
120
60
80
Particle
S&D
Flow
properties
+
--
+
--
Moisture
[wt%]wb
16.4
15.7
15.7
Feeding
Feeding section reactor
Biomass
Pitch
Stirrer
Screw diameter
Feeding screw
Injector screw
Feeding system
slide 15
Reactor
Feeding
Calibration
20
Core
15
Flow
10
[kg/hr]
Whole plant, milled
5
0
0
10
20
30
40
50
60
Rotational speed [rpm]
slide 16
70
80
Ash behaviour
Ash content and ash melting
> Both ash content and ash quality important
> Ash melting can cause damage to bio-energy system
> Ash melting can cause sintering of bed material
slide 17
Ash behaviour
Ash fusibility test
> Seger cone method
> ASTM D2013 - D3174 (for ash from coal and cokes)
> Oxidising (air) and inert environment (N2)
Initial
Cone
slide 18
IDT
ST
HT
FT
Initial
Deformation
Temperature
Softening
Temperature
Hemispherical
Temperature
Fluid
Temperature
Ash behaviour
Ash fusibility test - example
IDT
ash cones
ST
FT
slide 19
HT
Ash behaviour
Ash fusibility tests - results
Ash content Initial Deformation
Temperature
[wt%]
> 1270
> 1270
Kenaf Core
Kenaf Whole plant
2.0
2.4
Beech (hardwood)
Pyne (softwood)
2.3
0.3
> 1270
> 1270
Miscanthus
Switch grass
Arundo
2.0
4.8
4.5
1060
1080
1000
slide 20
Fluid
Temperature
>> 1270
>> 1270
>> 1270
>> 1270
1210
1230
1150
Ash behaviour
Ash fusibility tests - results
Non-oxidising environment
Entrained flow
/Slagging
Oxidising environment
1400
1400
1200
1200
1000
1000
800
800
600
600
Combustion
Fixed bed
Gasification
Fluid bed
Fast
Pyrolysis
Slow
400
400
1
2
Arundo
3
4
55
Kenaf
66
Initial Deformation temperature
Fluid temperature
slide 21
Gasification
Experimental set-up
slide 22
Gasification
Flow scheme
Product gas
Biomass
hopper
Ash
- Amount
- Carbon in ash
Biomass
Feeding
- Temperatures
- Pressure
Biomass
- Flowrate
700 900 °C
Air
- Flowrate
slide 23
- Composition
- N2
- O2
- H2
- CO
- CO2
- CH4
- C2/C3
- Flowrate
- Tar (composition/amount)
- Water
- H2S / HCl / NH3
Gasification
Temperature profiles
800
0.05 m (fluid bed)
0.35 m (feeding zone)
0.85 m (fluid bed)
2.2 m (freeboard)
1.2 m (freeboard)
Temperature [°C]
750
Bottom fluid bed
Top fluid bed
700
fluid bed - feeding point
Freeboard
Top Freeboard
650
600
13:40:48
13:55:12
14:09:36
14:24:00
14:38:24
14:52:48
Time
slide 24
15:07:12
15:21:36
15:36:00
15:50:24
Gasification
Axial temperature profile
Temperature [°C]
750
Fluid bed
Freeboard
700
Biomass
Feeding
650
600
0
0.5
1
1.5
Fluid bed position [m]
slide 25
2
2.5
Gasification
Results
Core
Whole plant
7.1
25
6.7
23.6
kg/hr
kW
8.4
5.8
kg/hr
15.7
12.3
kg/hr
9.1
8.1
20.3
2.6
1.5
58.3
11.9
8.2
23
3.3
1.9
51.7
vol%
vol%
vol%
vol%
vol%
vol%
Biomass feed
Flow rate
Energy in
Air supply
Flow rate
Product gas
Flow rate
Composition
H2
CO
CO2
CH4
C2+
N2
slide 26
Gasification
Results
Core
Whole plant
Product gas
Traces
NH3
H2S
HCl
Tar
> 100
40
<1
0.5
> 100
40
<1
0.3
ppm
ppm
ppm
g/m3
Biomass, in
25.0
23.6
kW
Gas, out
Tar, our
Ash/Char, out
13.6 (= 54.4 %)
1.8 (= 7 %)
1.8 (= 7 %)
11.4 (= 48 %)
1.1 (= 5 %)
1.4 (= 6 %)
kW
kW
kW
Total, out
17.3 (= 68.8 %)
13.9 (= 58.7%)
kW
Energy balance
slide 27
Combustion
Experimental set-up
> Fluidised bed combustion
> Experimental set-up and flow scheme corresponding to
gasification tests
slide 28
Combustion
Results - gas analysis Kenaf core
concentration [vol%]
4
3
CO
2
CH4
1
0
0.7
slide 29
H2
C2+
0.8
0.9
1
1.1
air normalized [-]
1.2
1.3
Combustion
Results - NOx emissions Kenaf core
200
NOx [ppm]
150
100
50
0
0.7
slide 30
0.8
0.9
1
1.1
air normalized [-]
1.2
1.3
Pyrolysis
Experimental set-up (new for Kenaf)
Feeding
system
Bio-oil condensing
system
Pyrolysis reactor system
(placed in hotbox)
slide 31
Pyrolysis
Flow scheme
Flue gas
Gas
Ash
Sand
Biomass
Vapours
Sand &
Char
Oil
Air
Pyrolysis
reactor
slide 32
Char
Combu sto r
Bio-oil
Con den sor
Pyrolysis
Planning of experiments
> Measurements:
– Bio-oil yield
– Bio-oil quality
– Mass and energy balance
> Time frame
–
–
–
–
slide 33
Testing of new set-up : week 26
Drying of Kenaf samples (< 8 wt% moisture): week 27
Calibration of samples in feeding section: week 27
Pyrolysis experiments planned for week 28