primairy fast pyrolysis products from pine-wood

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25/03/22 Title: to modify choose 'View' then 'Heater an d footer' 1 Primairy fast pyrolysis products from pine-wood A comparison between wire mesh and fluidized bed pyrolysis Elly Hoekstra, Roel Westerhof and Kees Hogendoorn

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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 Presentation

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19/04/23 Title: to modify choose 'View' then 'Heater and footer'

1

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

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