Pre-treatment Technologies

Jean-Luc Wertz and Prof. Michel Paquot

Lignofuels 2011 - 29 September 2011

PLAN

1. Introduction

2. Physical pre-treatments

3. Chemical pre-treatments (e.g. organosolv)

4. Physicochemical pre-treatments (e.g. steam explosion; AFEX)

5. Biological pre-treatments

6. Economic analysis (OPEX, CAPEX)

7. Performance summary

Average composition of lignocellulosic biomass

Cellulose: molecular structure

• Glucose units linked by β 1-4 glycosidic bonds• One reducing end and one non-reducing end• Linear straight polysaccharide

Hemicelluloses• High structural diversity• Monomers: pentoses and hexoses• Branched polysaccharides• Example: xyloglucans as shown below

Lignin

• Monomers : 3 different monolignols (H, hydroxyphenyl; G, guaïacyl; S, syringyl)

H

G

S

Lignin

Cross-linked polymers of monolignols

Schematic of the role of pre-treatment

Source: P. Kumar et al., 2009

Liquid hot water (LHW)Biomass pretreatment with water at high temperature and pressure

Inbicon’s hydrothermal pre-treatment pilot plant

Weak and strong acid hydrolysis

1 Weak acid:

-High-temperature (>160°C), continuous-flow process for low solids loadings

-Low-temperature (<160°C) batch process for high solids loadings

2. Strong acid:

Powerful agents for cellulose hydrolysis and no enzymes are needed after the concentrated acid process

Alkaline hydrolysis

Well known in the pulp and paper industry as kraft pulping

Extraction of lignin from Kraft pulp mill black liquor by the LignoBoost process

Source: Metso, LignoBoost

Schematic of the MixAlco® process (Terrabon, Inc.)

Source: Holtzapple et al., Terrabon

Organosolv processesSolvolytic cleavage of an alpha-aryl ether linkage by nucleophilic substitution; R=H or CH3; B=OH, OCH3

Some important organosolv processes

Process Name

Solvent / Additive

Asam Water + sodium carbonate + hydroxide + sulfide + methanol / Anthraquinone

Organocell

Water + sodium hydroxide + methanol

Alcell (APR)

Water+ low aliphatic alcohol

Milox Water + formic acid + hydrogen peroxide (forming peroxyformic acid)

Acetosolv Water + acetic acid/Hydrochloric acid

Acetocell Water + acetic acid

Formacell Water + acetic acid + formic acid

Formosolv

Water + formic acid + hydrochloric acid

Lignol’s process based on water/ethanol pre-treatment

Source: Lignol

lignocellulosic materials

heating

filtration

rinsing

washing

water precipitation

centrifugation

washing

Formic Ac./Acetic Ac./Water

Formic Ac./Acetic Ac./Water

Water

pulp

black liquors

Acidified water

pulp

pulp

black liquors

lignins

lignins

Water solubles

Water

CIMV process: formic acid / acetic acid / H2O

Source: C. Vanderghem et al., ULg-GxABT

,

CIMV process using acetic acid/formic acid/waterSource: C. Vanderghem et al., ULg-GxABT

Time

Tem

pera

ture

1,00,50,0-0,5-1,0

1,0

0,5

0,0

-0,5

-1,0

FA/AA/W 1Hold Values

> – – – < 60

60 7070 8080 90

90

YieldPulp

Contour Plot of Pulp Yield vs Temperature; Time

Time: 1h (-1), 2h (0), 3h(1). Temperature: 80°C (-1), 90°C (0), 107°C (1)

CIMV process using acetic acid/formic acid/waterSource: C. Vanderghem et al., ULg-GxABT

Temperature

FA/A

A/W

1,00,50,0-0,5-1,0

1,0

0,5

0,0

-0,5

-1,0

Time 1Hold Values

> – – – < 20

20 4040 6060 80

80

delignification% Of

Contour Plot of % Of delignification vs FA/ AA/ W; Temperature

Temperature: 80°C (-1), 90°C (0), 107°C (1).

FA/AA/W: 20/60/20 (-1) 30/50/20(0); 40/40/20 (1)

CIMV process using acetic acid/formic acid/waterSource: C. Vanderghem et al., ULg-GxABT

Time

Tem

pera

ture

1,00,50,0-0,5-1,0

1,0

0,5

0,0

-0,5

-1,0

FA/AA/W 1Hold Values

> – – – – – < 0

0 1010 2020 3030 4040 50

50

(ppm)Furfural

Contour Plot of Furfural (ppm) vs Temperature; Time

Time: 1h (-1), 2h (0), 3h(1). Temperature: 80°C (-1), 90°C (0), 107°C (1)

CIMV process using acetic acid/formic acid/waterSource: C. Vanderghem et al., ULg-GxABT

Temperature

FA/A

A/W

1,00,50,0-0,5-1,0

1,0

0,5

0,0

-0,5

-1,0

Time 1Hold Values

> – – – – < 30

30 4040 5050 6060 70

70

(%)digestibilityEnzymatic

Contour Plot of Enzymatic digestibility (% ) vs FA/ AA/ W; Temperature

Temperature: 80°C (-1), 90°C (0), 107°C (1).

FA/AA/W: 20/60/20 (-1) 30/50/20(0); 40/40/20 (1)

Oxidative delignification

1. Hydrogen peroxide treatment

2. Ozone treatment

3. Wet oxidation: treatment with oxygen or air in combination with water at high temperature and pressure

Room temperature ionic liquidsMain cations and anions in ionic liquids

Room temperature ionic liquidsDifferent types of interaction present in imidazolinium-based ionic liquids

Room temperature ionic liquidsProposed mechanism for cellulose dissolution in EmimAc

Room temperature ionic liquids

Hydrolysis of cellulose in a mixture of cellulases and an ionic liquid (HEMA)

+

Steam explosionSchematic of the steam explosion process. 1, sample charging valve; 2, steam supply valve; 3, discharge valve; 4, condensate drain valve

ULg-Gembloux Agro-Bio Tech steam explosion pilot plant (Source: N. Jacquet et al.)

ULg-Gembloux Agro-Bio Tech steam explosion pilot plant (Source: N. Jacquet et al.)

Ulg-GxABT steam explosion pilot plant (Source: N. Jacquet et al.)

Ammonia pre-treatments

1. Ammonia fiber explosion (AFEX™): biomass is exposed to liquid ammonia at high temperature and pressure and then pressure is reduced

2. Ammonia recycle percolation (ARP): aqueous ammonia passes through biomass at high temperature, after which ammonia is recovered

Ammonia Fiber Expansion Process– Moist biomass is contacted with ammonia – Temperature and pressure are increased – Contents soak for specified time at temperature and ammonia load– Pressure is released – Ammonia is recovered and reused

Reactor Explosion

AmmoniaRecoveryRecovered

AmmoniaAmmonia

vapor

Reactor Expansion

Ammonia Recovery

BiomassTreatedBiomass

Heat

What is AFEX™?

AFEX™ is a trademark of MBI

Glucan conversion for various AFEX treated Feed stocks

SwitchgrassSugarcaneBagasse

DDGS

Rice straw

Corn stover

Miscanthus

UT=No PretreatmentAFEX=Ammonia Pretreatment

Biomass Conversion for Different Feedstocks Before and After AFEX

Glucan conversion afterenzymatic hydrolysis

Excellent Biomass Conversion After AFEX Pretreatment

Carbon dioxide explosion

High pressure carbon dioxide, and particularly supercritical carbon dioxide is injected into the reactor and then liberated by an explosive decompression

Mechanical/alkaline pre-treatment

Continuous mechanical pre-treatment with the aid of an alkali

Biological pre-treatmentsWhite-rot fungi are the most efficient in causing lignin degradation

Source: L. Goodeve, 2003

Source: R.A. Blanchette, 2006

XX: Major effect; X: Minor effect;; *: increases crystallinity; 1) alters lignin structureInhibitors: furfural from hemicelluloses and hydroxymethylfurfural from cellulose and hemicelluloses

PretreatmentDecrystallization of

celluloseRemoval of

hemicellulosesRemoval of

ligninInhibitor

formation

Liquid hot water1) XX XX

Weak acid1) XX XX

Alkaline X XX

Organosolv X3 XX

Wet oxidation XX X XX

Steam explosion* 1) XX XX

Ammonia fiber explosion (AFEX)

XX X

CO2 explosion XX XX

Mechanical/alkaline

X XX

Biological XX XX

Performance summary

Performance summary

1. All pretreatments partially or totally remove hemicelluloses

2. Wet oxidation, AFEX and CO2 explosion reduce cellulose crystallinity

3. Alkaline, organosolv, wet oxidation, mechanical/alkaline and biological partially or totally remove lignin

4. High amounts of fermentation inhibitors are formed with liquid hot water, weak acid and steam explosion

PretreatmentOPEX ($/gal EtOH)

CAPEX($/gal annual

capacity)

Liquid hot water 1.65 4.57

Weak acid 1.35 3.72

Alkaline 1.60 3.35

Organosolv

Wet oxidation

Steam explosion

Ammonia fiber explosion (AFEX)

1.40 3.72

Ammonia recycle percolation (ARP)

1.65 4.56

Ideal 1.00 2.51

ECONOMIC ANALYSIS: OPEX (Minimum Ethanol Selling Price), CAPEX

Source: Eggeman et al., 2005NB Enzyme cost: EUR 3/kg of produced cellobiose

Thank you for your attention