primairy fast pyrolysis products from pine-wood
DESCRIPTION
Primairy fast pyrolysis products from pine-wood. A comparison between wire mesh and fluidized bed pyrolysis. Elly Hoekstra, Roel Westerhof and Kees Hogendoorn. Aim. Study the primary pyrolysis processes and to clarify the primary reaction mechanisms . - PowerPoint PPT PresentationTRANSCRIPT
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Primairy fast pyrolysis products from pine-woodA comparison between wire mesh and fluidized bed pyrolysis
Elly Hoekstra, Roel Westerhof and Kees Hogendoorn
Aim
Study the primary pyrolysis processes and to clarify the primary reaction mechanisms.
By understanding of the primary fast pyrolysis mechanism it may be possible to develop methods to steer the final pyrolysis oil composition.
Aim Set-up Primary Conversion Rate Biomass Loading Temperature ConclusionsAim
Wire-Mesh reactor
1 Mesh/wood sample2 Vessel 3 Vacuum pump4 Liquid nitrogen bath 5 Syringe
2
1
4
3
5
Aim Set-up Primary Conversion Rate Biomass Loading Temperature ConclusionsSet-up
0
100
200
300
400
500
600
0 3 6 9Time [s]
T [
0 C]
holding time
Operating conditions
Aim Set-up Primary Conversion Rate Biomass Loading Temperature ConclusionsSet-up
Heating rate 7000 0C/s
Temperature Uniformity Mesh ± 35 0C
Temperature Fluctuations ± 5 0C
Vapor residence time < 15 ms
Movies
Vacuum and Cooling Atmospheric without Cooling
Aim Set-up Primary Conversion Rate Biomass Loading Temperature ConclusionsSet-up
Primary versus Secondary: Yields
0
25
50
75
100
PvacCooling
Patm Nocooling
PilotPlant
Yie
ld [
wt%
]Oil Gas Char
Aim Set-up Primary Conversion Rate Biomass Loading Temperature Conclusions..Primary
Primary versus Secondary: Mw-distribution
0,0
0,5
1,0
1,5
2,0
2,5
100 1000 10000M [g/mol]
W(l
og
M)
Pilot Plant Patm No Cooling Pvac Cooling
Aim Set-up Primary Conversion Rate Biomass Loading Temperature Conclusions..Primary
Primary versus Secondary: SEM
melting/evaporation physical entrainment
Aim Set-up Primary Conversion Rate Biomass Loading Temperature Conclusions..Primary
Primary versus Secondary: sugars
Observation:A THF insoluble fraction but water soluble fraction was observed for the experiments carried out using vacuum and cooling
HPLC Analyses (RUG)This fraction contained mainly sugars
Model compound study: glucose and levoglucosanThese compounds were evaporated and condensed without reactions taken place
Aim Set-up Primary Conversion Rate Biomass Loading Temperature Conclusions..Primary
Primary fast pyrolysis processes:
High oil yields (> 80 wt%)
Extremely low char yields (~ 5 wt%)
Presence of high molecular weight products
Presence of sugars
Less alkane like groups (NMR)
Aim Set-up Primary Conversion Rate Biomass Loading Temperature Conclusions..Primary
Effect holding time: yields
Aim Set-up Primary Conversion Rate Biomass Loading Temperature ConclusionsAim Set-up Primary Conversion Rate Biomass Loading Temperature ConclusionsConversion Rate
0
20
40
60
80
100
0 1 2 3holding time [s]
Yie
ld [
wt%
]
Oil
GasChar
Effect holding time: gas and char composition
500150025003500Wavenumber [cm-1]
Tra
nsm
itta
nc
e [%
]
Pine Wood
0 s
1 s
3 s
Aim Set-up Primary Conversion Rate Biomass Loading Temperature ConclusionsConversion Rate
0
20
40
60
0 1 2 3Holding time [s]
mo
l%
CO2 CO
CH4
HH
Experimental progress: “Grey Intensity Method”
Experimental Progress
Aim Set-up Primary Conversion Rate Biomass Loading Temperature ConclusionsConversion Rate
Conversion rate: experimental progress
0
0,2
0,4
0,6
0,8
1
0 1 2 3Time [s]
Gre
y In
ten
sity
[-]
Reactions approximately completed
Aim Set-up Primary Conversion Rate Biomass Loading Temperature ConclusionsConversion Rate
Comparison with C. Di Blasi and C. Branca [2001]*
Aim Set-up Primary Conversion Rate Biomass Loading Temperature ConclusionsConversion Rate
Colomba Di Blasi* and Carmen Branca, Kinetics of Primary Product Formation from Wood Pyrolysis, Ind. Eng. Chem. Res. 2001, 40, 5547-5556
0
20
40
60
80
100
0 1 2 3Holding time [s]
Yie
ld [w
t%] Oil
GasChar
Reactions approximately completed
Conversion rate
The majority of the reactions in our wire-mesh reactor was finished within 0.5 s.
Our results indicate that the actual primary pyrolysis process is faster than previously thought
Aim Set-up Primary Conversion Rate Biomass Loading Temperature ConclusionsConversion Rate
Biomass loading
0
20
40
60
80
100
0,04 0,06 0,08 0,10m [g]
Yie
ld [
wt%
]
Oil
Gas
Char0
20
40
60
80
0,04 0,06 0,08 0,10m [g]
mo
l%
CH4
CO
CO2
HH
Aim Set-up Primary Conversion Rate Biomass Loading Temperature Conclusions..Biomass Loading
Although the absolute biomass was small, the results are still influenced by secondary reactions, the extent is increasing with biomass loading.
Temperature: yields
Wire-Mesh reactor Pilot Plant
Aim Set-up Primary Conversion Rate Biomass Loading Temperature Conclusions..Temperature
0
20
40
60
80
100
200 400 600 800T [0C]
Yie
ld [
wt%
]
Oil
Gas
Char
0
20
40
60
80
100
200 400 600 800T [0C]
Yie
ld [
wt%
]
Oil
GasChar
Temperature: gas composition
0
20
40
60
80
100
200 400 600 800T [0C]
mo
l %
CO2 CO
CH4
HH
Wire-Mesh reactor Pilot Plant
0
20
40
60
80
100
200 400 600 800T [0C]
mo
l %
CO2CO
CH4
HH
Aim Set-up Primary Conversion Rate Biomass Loading Temperature Conclusions..Temperature
Temperature: Mw-distribution
0,0
0,4
0,8
1,2
1,6
100 1000 10000M [g/mol]
W(l
og
M)
7000C
3250C
4500C
Aim Set-up Primary Conversion Rate Biomass Loading Temperature Conclusions..Temperature
0,0
0,6
1,2
1,8
2,4
100 1000 10000 100000M [g/mol]
W(l
og
M)
5800C
3600C
5300C
Wire-Mesh reactor Pilot Plant
Temperature: Mw-distribution
0,0
0,4
0,8
1,2
1,6
100 1000 10000M [g/mol]
W(l
og
M)
7000C
3250C
4500C
0,0
0,4
0,8
1,2
1,6
100 1000 10000M [g/mol]
W(l
og
M)
7000C
3250C
4500C
Aim Set-up Primary Conversion Rate Biomass Loading Temperature Conclusions..Temperature
0,0
0,6
1,2
1,8
2,4
100 1000 10000 100000M [g/mol]
W(l
og
M)
5800C
3600C
5300C
0,0
0,6
1,2
1,8
2,4
100 1000 10000 100000M [g/mol]
W(l
og
M)
5800C
3600C
5300C
Wire-Mesh reactor Pilot Plant
Temperature: Mw-distribution
0,0
0,4
0,8
1,2
1,6
100 1000 10000M [g/mol]
W(l
og
M)
7000C
3250C
4500C
0,0
0,4
0,8
1,2
1,6
100 1000 10000M [g/mol]
W(l
og
M)
7000C
3250C
4500C
Aim Set-up Primary Conversion Rate Biomass Loading Temperature Conclusions..Temperature
0,0
0,6
1,2
1,8
2,4
100 1000 10000 100000M [g/mol]
W(l
og
M)
5800C
3600C
5300C
0,0
0,6
1,2
1,8
2,4
100 1000 10000 100000M [g/mol]
W(l
og
M)
5800C
3600C
5300C
Wire-Mesh reactor Pilot Plant
Temperature
Decrease in oil yield Still cracking reactions possible under the extreme conditions in our set-up
However the yield is still above 60 wt% at 700 0C
Heavier products formed at higher temperatures Heavier molecules can evaporate at higher temperatures
Cracking is minimized inside the wire-mesh reactor
Aim Set-up Primary Conversion Rate Biomass Loading Temperature Conclusions..Temperature
Conclusions
Primary pyrolysis compared to conventional pyrolysis
High oil yields (> 80 wt%) and extremely low char yields (~ 5 wt%) Less alkane like groups (NMR) High molecular weight products and sugars Heavier products formed at higher temperatures Extremely fast conversion rate
However, secondary cracking reactions are extremely fast
Inside biomass layer At high temperatures
Aim Set-up Primary Conversion Rate Biomass Loading Temperature Conclusions..Conclusions