Pre-treatment Technologies

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

Lignin

• Monomers : 3 different monolignols

(H,

hydroxyphenyl; G, guaïacyl; S, syringyl)

H

G

Lignin

Schematic of the role of pre-treatment

Liquid hot water (LHW)

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

Extraction of lignin from Kraft pulp mill

black liquor by the LignoBoost process

Schematic of the MixAlco® process

(Terrabon, Inc.)

Organosolv processes

Solvolytic 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

Organocel

l 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

Formosol

Lignol’s process based on

water/ethanol pre-treatment

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/water

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

Time Te m p e ra tu re 1,0 0,5 0,0 -0,5 -1,0 1,0 0,5 0,0 -0,5 -1,0 FA/AA/W 1 Hold Values > – – – < 60 60 70 70 80 80 90 90 Yield Pulp

Contour Plot of Pulp Yield vs Temperature; Time

CIMV process using acetic acid/formic acid/water

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

Temperature FA / A A / W 1,0 0,5 0,0 -0,5 -1,0 1,0 0,5 0,0 -0,5 -1,0 Time 1 Hold Values > – – – < 20 20 40 40 60 60 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/water

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

Time Te m p e ra tu re 1,0 0,5 0,0 -0,5 -1,0 1,0 0,5 0,0 -0,5 -1,0 FA/AA/W 1 Hold Values > – – – – – < 0 0 10 10 20 20 30 30 40 40 50 50 (ppm) Furfural

Contour Plot of Furfural (ppm) vs Temperature; Time

CIMV process using acetic acid/formic acid/water

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

Temperature FA / A A / W 1,0 0,5 0,0 -0,5 -1,0 1,0 0,5 0,0 -0,5 -1,0 Time 1 Hold Values > – – – – < 30 30 40 40 50 50 60 60 70 70 (%) digestibility Enzymatic

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 liquids

Room temperature ionic liquids

Different types of interaction present in imidazolinium-based ionic liquids

Room temperature ionic liquids

Room temperature ionic liquids

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

Steam explosion

Schematic 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

ULg-Gembloux Agro-Bio Tech steam

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

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

Ammonia

Recovery

Recovered

Ammonia

Ammonia

_vapor

Reactor

Expansion

Ammonia

Recovery

Biomass

_Biomass

Treated

Heat

What is AFEX™?

Glucan conversion for various AFEX treated Feed stocks

Biomass Conversion for Different

Feedstocks Before and After AFEX

Glucan conversion after enzymatic hydrolysis

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-treatments

White-rot fungi are the most efficient in causing lignin degradation

Source: L. Goodeve, 2003

XX: Major effect; X: Minor effect;; *: increases crystallinity; 1) alters lignin structure

Inhibitors: furfural from hemicelluloses and hydroxymethylfurfural from cellulose and hemicelluloses

Pretreatment Decrystallization of _{cellulose hemicelluloses}Removal of Removal of _{lignin formation}Inhibitor

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/alkali ne 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

Pretreatment OPEX ($/gal EtOH) CAPEX ($/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., 2005

NB Enzyme cost: EUR 3/kg of produced cellobiose