TORREFACTION OF AGRICULTURAL AND …...Torrefaction of agricultural and forestry feedstocks in a...

TORREFACTION OF AGRICULTURAL AND FORESTRYFEEDSTOCKS IN A PILOT SCALE FACILITY:COMPARISON OF MASS AND ENERGY BALANCEST. Melkior, M. Perez, S. Thiéry, P. Ponsdevincent,A. Chatroux, M. Gonzalez Martinez, C. Dupont

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Biomass torrefaction

GONZALEZ MARTINEZ MaríaTorrefaction of agricultural and forestry feedstocks in a pilot scale facility: comparison of mass and energy balances

200– 300°C

P(atm)10min– 1h

Inert atmosphere

§ ↑heating value

§ hydrophobic

§ ↑flowability

§ ↑grindability

§ usesRaw biomass

Torrefiedsolid

Gaseous products

§ harmful fortheprocess

§ chemicals (added value)

↓transportcost

Energy

Chemicals

Materials

~70%mass

Permanentgases (CO,CO2)

Volatilespecies (furans,ketones,phenols)

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Biomass torrefaction upscaling


Mobile Flip WP 2.4. Torrefaction Mobile Flip WP 3à Next presentation

This presentationàPresentation 242 and poster 534

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Objectives

÷Studying biomass torrefaction behavior in large-scale tests:• Biomass conveying• Mass balances• Energy balances

÷Large-scale production of torrefied biomasses for testing new applicationsof the torrefied products:

• Pelletizing à presentation 445 -298

• Soil amendment à presentation 442

• Particle boards manufacturing à oral flash/poster 480


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Génépi research facility


Grinding

Torrefaction

Gasification

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Centorré torrefaction oven


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Feedinghopper

(dry biomass)

Natural gasCH4

O2

N2

Gas topost-combustion

Outlet flowto the container

.

Air cooler

Multiple-hearth torrefactionfurnace

- Temperature: 200-350°C

- Mass flow: 50-150 kg/h

- Atmospheric pressure

- Feedstock: chips or pellets:

wood, agricultural residues,non-hazardous waste

- Moisture < 10 % (after drying)

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Centorré scheme oftheoven

Rabbling system

Centorré (2soils) Post-combustion

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Composition of the products


÷Solid product: mass loss ajusted by:• Temperature• Residence time (related to the speed of rotation of the oven)

÷Gaseous products:

• Gases include He (tracer gas) and combustion-derived gases from the burners (H2O, CO2 and residual CH4)

• Water (~ 80% of the total condensable species)

• Dry condensables (cold trap + GC/FID):

• Dry permanent gases (µ-GC):

• N2: 80%

• CO2: 10%

• CO: 2-3%

• O2: 2-3 %

• Traces of H2, CH4, C2H4,

C2H6, C3H8 and H2.

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Materials tested and operating conditions


Wheat strawBeech Poplar

250°C, 75 minutes

Ope

ratin

gco

nditi

ons

250°C, 75 minutes

250°C, 90 minutes

280°C, 30 minutes

280°C, 60 minutes

250°C, 20 minutes

250°C, 60 minutes

15 mm: 250°C, 75 min

15 mm: 260°C, 45 min

30 mm: 250°C, 75 min

Corn cob

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Biomass conveying


Poplar250°C, 90 minutes

Wheat straw250°C, 20 minutes

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Mass and energy balances


CENTORRE

Flow rateCHO contents

LHV

Gas analysis: N2, CO2, CO, O2, CH4He content => gas flow rateCondensables: trapping and analysis

Torrefiedbiomass

Gas andvolatiles

At each level: gas and floortemperature

flow ratewater contentC, H, O contentsLHV

Gas flow rates

Depression into the oven

Gas flow rate

Biomass

Air + natural gas

Air entries (leaks)

He

N2 sweeping

Air entries (biomass)

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Mass balance: example for beech


CENTORRE

Biomass

Air + natural gas

Air entries

He

Torrefied biomass Gas + volatile species

136 - 168 kg/hWater content: 9 - 7 %

100 - 129 kg/hMass loss: 20%db

N2 sweeping2.4 Nm3/h

0.15 Nm3/h

3.3 - 3.8 Nm3/h31 - 35 Nm3/h

12.4 Nm3/h

Air entries (biomass)0.2 - 0.3 Nm3/h

0.5 kg / Nm3 (db)Water content: 80%m

(dry gases)51 - 57 Nm3/h

250°C, 75 min

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Energy balance


T

Resid

ence

time

Wat

erco

nten

t

Inle

tmas

sflo

w

Inle

tdry

biom

ass

Inle

tWat

er

Wat

erhe

atin

g

Wat

erev

apor

atin

g

Stea

mh

eatin

g

Solid

heat

ing

Tota

lre

quire

d

Net

natu

ral

gas

cons

umpt

ion

Net

ener

gysu

pplie

d

Biomass °C tmin %db kg/h Kg/h Kg/h MJ/h MJ/h MJ/h MJ/h MJ/h Nm3/h MJ/h

Poplar chips

250 75 4.5% 156 149 7 2.3 15.8 2.1 44.5 65 1.63 67

250 90 3.0% 158 153 5 1.6 10.7 1.4 45.8 60 1.04 43

280 30 4.0% 129 124 5 1.7 11.6 1.9 41.9 57 1.46 60

280 60 4.5% 127 121 6 1.9 12.9 2.1 41.0 58 1.81 74

Corn cob 30mm 250 75 8.0% 171 157 14 4.6 30.9 4.1 47.0 87 1.47 60

Corn cob 15mm250 75 8.0% 180 166 14 4.8 32.5 4.3 49.5 91 2.1 86

260 45 8.0% 183 168 15 4.9 33.0 4.7 52.5 95

Beech chips 250 75 9.40% 136 123 13 4.3 28.9 3.8 36.8 74 1.4 57

Wheat straw 250 20 10.0% 95 86 10 3.2 21.4 2.9 25.6 53 1.1 45

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Conclusions

÷Large-scale production of torrefied biomasses succesful÷Comparison of biomass conveying (woody/agricultural biomasses)÷Difficulties in wheat straw conveying

÷Final mass loss of the torrefied biomasses:÷Adjusted through operating coniditions÷Depedent on biomass properties (composition, moisture)

÷Preliminary study for mobile unit design


Perspectives

÷Torrefaction tests on sunflower seed shells÷Improving biomass conveying

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