Lund University Experience on Technology Assessment for 2nd Generation

Bioethanol Production

Workshop Virtual Sugarcane BiorefineryCampinas August 13-14

Guido Zacchi, Chemical EngineeringLund Universitywww.chemeng.lth.se

Schematic process

SSF

Enzymatic hydrolysis

Ferment-ation Distillation

EthanolPre-treatment

Biomass

Lignin

Steam pretreatment Acid hydrolysis

Fermentation of all sugars (incl. Pentoses)

Simultaneous saccharification and fermentation (SSF)

Energy integration

Integration with other processes

Steam pretreatment unit

Main purposes

Hydrolysis of hemicellulose

Improve the enzymatic hydrolysis of cellulose

10 litre reactor160 - 230 CImpregnation with H2SO4 or SO2

Equipment for enzymatic hydrolysis and fermentation (SSF)

Productioncost (SEK/L)

Vendorquotations

Mass & energy balancesThermodynamic calculations

Techno-Economic Evaluation

Aspen Plus

Icarus Process EvaluatorSizing & cost estimation of

process equipment

Swedishconditions

Experimental data

High quality data are crucial Experimental data for all conversions Physical data Phase equilibria Cost data Etc

Rubish in = Rubish out(Independent of how good the model is)

Useful for Sensitivity analysis

(solid content in SSF)

Compare different process configurationsone versus two stage pretreatmentreplace evaporation of stillage with biogas production

Internal process integrationrecirculation of process streams

External process integrationwith heat and power productionwith 1G ethanol production

10

12

14

16

18

20

22

24

26

28

7 8 9 10 11 12 13 14 15WIS concentration in SSF (%)

Hea

t dut

y (M

J/L

eth

anol

)

SalixCorn stoverSpruce

Sassner, Thesis LU 2007

Overall process heat demand as functionof the WIS concentration in SSF

3,50 kr

4,00 kr

4,50 kr

5,00 kr

5,50 kr

6,00 kr

6,50 kr

7 8 9 10 11 12 13 14 15WIS concentration in SSF (%)

Etha

nol p

rodu

ctio

n co

st (S

EK/L

)

SalixCorn stoverSpruce

Sassner, Thesis LU 2007

Ethanol production cost as functionof the WIS concentration in SSF

Fed-batch SSF yeast cultivated on hydrolysate Above 45 g/l etanol 2 g/l yeast

12 % FibresFed-Batch SSF

05

101520253035404550

0 50 100 150 200

Time (h)

Conc

entra

tions

(g/L

)

Glucose

Ethanol

010

20

30

40

50

60

70

80

90

0 24 48 72 96 120 144Time (Hours)

Etha

nol c

once

ntra

tion

(g/l)

20% WIS

15% WIS

10% WIS

SSF of pretreated and delignified aspen

New reactor

Conventionalfermentor

Fermentation test

solid

liquid

Raw material

Pretreatmentstep 1

Pretreatmentstep 2

SSF

slurry

Enzymatichydrolysis

2-step pretreatmentExperimental set-up

Comparison yields

0

20

40

60

80

100

Glu

cose

Man

nose

Tota

l

Glu

cose

Man

nose

Tota

l

Glu

cose

Man

nose

Tota

l

LiquidSolidTotal

OS TS+W TS-W

Rec

over

y af

ter p

retre

atm

ent (

%)

Economic evaluation

Steam

SteamHX1

HX2

HX4

HX3Catalyst

Catalyst

HX7

To SSF To SSF

Wood

First step Optional second step

HX5

HX6

HX871.8%74.6%

Coolingto 20C

No flashing50% WIS

77.0%no flashingno washing50% WIS

Ethanol cost (SEK/L)

3.5

3.6

3.7

3.8

3.9

4.0

4.1

4.2

4.3

BC one-step BC two-step Worst case No flash case Optimistic case

Etha

nol c

ost (

SEK/

L)

Water &baseSO2

Feedstockhandling

Pre-treatment

SSF & yeastcultivation

Raw material Enzymes &nutrientsSteam

Distillation& dehydr.

FiltrationEvaporation Liquidfraction

Ethanol

Concentrated liquid

Steam &electr. gen.

Excesssolids

Processsteam

Wastewatertreatment

Biogas (methane)

Stillage

Condensates

Electricty

Drying

Pelletproduction

Pellets

The ProcessReplacement of evaporation with Biogas production

The Process with biogas

Water &baseSO2

Feedstockhandling

Pre-treatment

SSF & yeastcultivation

Raw material Enzymes &nutrientsSteam

Distillation& dehydr.

FiltrationLiquidfraction

Ethanol

Steam &electr. gen.

Excesssolids

Processsteam

Wastewatertreatment

Biogas (methane) & sludge

StillageElectricty

Drying

Pelletproduction

Pellets

The Process

Water &baseSO2

Feedstockhandling

Pre-treatment

SSF & yeastcultivation

Raw material Enzymes &nutrientsSteam

Distillation& dehydr.

FiltrationLiquidfraction

Ethanol

Steam &electr. gen.

Excesssolids

Processsteam

Wastewatertreatment

Biogas

StillageElectricty

Drying

Pelletproduction

Pellets

Biogasupgrading

Vehiclefuel

Sludge

Minimum EtOH selling price

4.53 kr4.27 kr

3.42 kr

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

Base case No Evap - Pellets No Evap - Biogas

MES

P (S

EK/L

)

Biogas production

Two key issues:

- Biogas conversion:

- Yield? Rate? Concentration?

- Sludge handling:

- Fuel properties? Level of dewatering?

Recycling of process streams

SSF

Recirculation of process streams in SSF

3,80

4,00

4,20

4,40

4,60

4,80

0 20 40 60 80

% recycling of stream

Ove

rall

prod

uctio

n co

st (S

EK/L

)

BeforeAfter

Maximum Experimental value

Evaporation condensate up to 100%

Water &baseSO2

Feedstockhandling

Pre-treatment

SSF & yeastcultivation

Raw material Enzymes &nutrientsSteam

Distillation& dehydr.

FiltrationEvaporation Liquidfraction

Ethanol

Concentrated liquid

Steamgeneration

Excesssolids

Processsteam

Wastewatertreatment

Biogas (methane)

Stillage

Condensates

Integration with heat and power

Drying

Pelletproduction

Pellets

Schematic flowsheet

Water &baseSO2

Feedstockhandling

Pre-treatment

SSF & yeastcultivation

Raw material Enzymes &nutrientsSteam

Distillation& dehydr.

FiltrationEvaporation Liquidfraction

Ethanol

Concentrated liquid

Steam &electr. gen.

Excesssolids

Processsteam

Wastewatertreatment

Biogas (methane)

Stillage

Condensates

Electricty

Drying

Pelletproduction

Pellets

No pellet production

5 ScenariosA B C D E

Ethanol X X X X XPellets X XElectricity X X X XDistrict heating X X

BC: base caseLO: lower yieldHI: higher yield

WIS: reduced energy demandHI&WIS: combined case

Energy efficiency

53%

70% 70%76%

92%

0%10%20%30%40%50%60%70%80%90%

100%LO BC H

IW

ISH

I&W

IS LO BC HI

WIS

HI&

WIS LO BC H

IW

ISH

I&W

IS LO BC HI

WIS

HI&

WIS LO BC H

IW

ISH

I&W

IS

A B C D E

Ener

gy ef

ficie

ncy L

HV

HeatElectricityPelletsEthanol

Min. EtOH selling price

3.87

4.20

4.56

4.734.65

3.00

3.20

3.40

3.60

3.80

4.00

4.20

4.40

4.60

4.80

LO BC HI

WIS

HI&

WIS LO BC H

IW

ISH

I&W

IS LO BC HI

WIS

HI&

WIS LO BC H

IW

ISH

I&W

IS LO BC HI

WIS

HI&

WIS

A B C D E

MES

P (S

EK/L

)

Effect of feedstock cost

3,00

3,25

3,50

3,75

4,00

4,25

4,50

4,75

5,00

5,25

5,50

5,75

100 120 140 160 180 200

Feedstock cost (kr/MWh)

ME

SP (k

r/L

)

A

B

C

D

E

Effect of electricity spot price

3,00

3,25

3,50

3,75

4,00

4,25

4,50

4,75

5,00

200 250 300 350 400 450 500

Electricity spot price (kr/MWh)

MES

P (k

r/L)

A

B

C

D

E

Effect of district heat credit

3,00

3,25

3,50

3,75

4,00

4,25

4,50

4,75

5,00

100 150 200 250 300

Credit, district heat (kr/MWh)

MES

P (k

r/L)

A

B

C

D

E

Starch based process

Cellulose based process

Liquefaction

Enzymes

Fermentation Centrifug-ation

Liquid

water &steam

Sacchari-fication

Water

Distillation

Enzymes Yeast Ethanol Solid material

Raw material

SSF

Pretreatment Fermentation

Steam

Enzymatichydrolysis

Water Enzymes Yeast

SSF

1 2

Solid material

3 4

Solid material

Raw material Filtration

Liquid

Distillation

Ethanol Solid material

Integration of 1st and 2nd generation ethanol

010

20

30

40

50

60

0 20 40 60 80 100

Time [hour]

Etha

nol c

once

ntra

tion

[g/l]

SSF of wheat straw wheat meal (5% WIS)

5% straw

2.5% straw + 2.5% mealYield

92%

81%

Powerful tool Assessment of improvements What if - studies Sensitivity analysis Give guidelines for experimental work Give data for LCA Basic data for process design

Thanks for your attention!

Slide Number 1Slide Number 2Slide Number 3Slide Number 4Slide Number 5Slide Number 6Slide Number 7Slide Number 8Slide Number 9Slide Number 10Fed-batch SSF yeast cultivated on hydrolysateSlide Number 12Slide Number 13Slide Number 14Slide Number 15Slide Number 16Slide Number 17Slide Number 18Slide Number 19Slide Number 20Slide Number 21Slide Number 22Slide Number 23Slide Number 24Slide Number 255 ScenariosSlide Number 27Slide Number 28Slide Number 29Slide Number 30Slide Number 31Slide Number 32Slide Number 33Slide Number 34Slide Number 35