1. Technologies de prétraitement
Jean-Luc Wertz and Prof. Michel Paquot
VALEBIO 23 mars 2012

2. PLAN 1 Transformation de la biomasse en énergie et produits
1.1 La bioraffinerie
1.2 Voie biochimique
1.3 Voie thermochimique
2 Prétraitements
2.1 Prétraitements physiques
2.2 Prétraitements chimiques (p. ex. organosolv)
2.3 Prétraitements physico-chimiques (p. ex. steam explosion)
2.4 Prétraitements biologiques
2.5 Résumé

3. Définition Bioraffinage
Le bioraffinage est le processus durable de transformation de la biomasse en:
1. bioénergie (biocarburants, électricité, chaleur)
2. produits biobasés (alimentation, produits chimiques, matériaux)

4. Raffineries de 1ère et 2ème génération
Première génération: raffinage à partir de biomasse alimentaire (canne à sucre,, grains de maïs, huile végétale…)
Deuxième génération: raffinage à partir de biomasse non alimentaire (résidus agricoles et forestiers, déchets municipaux…)

5. Crude oil refining

6. Biomass refining

7. Procédés de transformation
Plateforme biochimique
- Hydrolyse acide (dilué ou concentré)
- Hydrolyse enzymatique
Plateforme thermochimique
- Combustion
- Gazéification
- Pyrolyse & traitement hydrothermique

8. Dilute acid hydrolysis

9. Concentrated acid hydrolysis

10. Enzymatic hydrolysis

11. Plateforme biochimique
Défis
- Prétraitement de la biomasse
- Coût et efficacité des enzymes
- Fermentation des sucres C5 and C6
- Valorisation de la lignine

12. Thermochemical conversion: primary routes

13. Gazéification + Fischer-Tropsch
Conversion de la biomasse en gaz de synthèse ou syngas (H2 + CO) suivie de la conversion du syngas par synthèse Fischer-Tropsch en carburants liquides (BtL)
Synthèse Fischer-Tropsch

14. Pyrolyse + conversion catalytique
Conversion de la biomasse en bio-huiles, eux-mêmes convertis en carburants liquides

15. Schematic of the role of pretreatment
Source: P. Kumar et al., 2009

16. Pretreatment with liquid water at high temperature and pressure
Liquid hot water (LHW)
Pretreatment with liquid water at high temperature and pressure
Source: N. Mosier et al., 2005

17. Liquid hot water
Performance: Strong removal of hemicelluloses but formation of inhibitor
Inbicon’s hydrothermal pretreatment pilot plant Source: Inbicon

18. 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
Performance: Strong removal of hemicelluloses but formation of inhibitors
2. Strong acid:
Powerful agents for cellulose hydrolysis (no enzymes are needed after the strong acid process)
Performance: High monomeric sugar yield but toxic and corrosive

19. Alkaline hydrolysis
Well known in the pulp and paper industry as kraft pulping (or sulfate process) where wood chips are treated with a mixture of NaOH and Na2S
Performance: Weak removal of hemicelluloses, strong removal of lignin

20. Extraction of lignin from Kraft pulp mill black liquor by the LignoBoost process
Precipitation of lignin from black liquor by lowering the pH with CO2
Dewatering by filtration
Redispersion of lignin
Dewatering by filtration of the new slurry
Washing to produce lignin cakes
Source: Metso, LignoBoost

21. Organosolv processes
Solvolytic cleavage of an alpha-aryl ether linkage by nucleophilic substitution; R=H or CH3; B=OH, OCH3
Performance: Weak removal of hemicelluloses, strong removal of lignin

22. 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 (e.g. ethanol)
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

23. Lignol’s process based on water/ethanol pre-treatment
Source: Lignol

24. Oxidative delignification
Hydrogen peroxide treatment
Ozone treatment
Wet oxidation: treatment with oxygen or air in combination with water at high temperature and pressure
Performance: Decrystalisation of cellulose, weak removal of hemicelluloses, strong removal of lignin

25. Room temperature ionic liquids
Main cations and anions in ionic liquids
Performance: Partial to complete dissolution of biomass with easy recovery of cellulose upon anti-solvent addition

26. Room temperature ionic liquids
Different types of interaction present in imidazolinium-based ionic liquids
Source: H. Olivier-Bourbigou, 2010

27. Room temperature ionic liquids
Proposed mechanism for cellulose dissolution in EmimAc (1-ethyl- 3-methyl imidazolium acetate)
Source: J. ZHANG et al., 2010

28. Room temperature ionic liquids
Hydrolysis of cellulose in a mixture of cellulases and tris-(2-hydroxyethyl) methyl ammonium methylsufate (HEMA) +
Source: S. Bose et al., 2010

29. Steam explosion
Schematic of the steam explosion process. 1, sample charging valve; 2, steam supply valve; 3, discharge valve; 4, condensate drain valve
Principle:
Treatment of biomass with high-pressure saturated steam, followed by a rapid reduction of steam pressure to obtain an explosive decompression
Performance: Strong removal of hemicelluloses but formation of inhibitors
Source: T. Jheo, 1998

30. Ammonia pre-treatments
Ammonia fiber explosion (AFEX™): biomass is exposed to liquid ammonia at high temperature and pressure and then pressure is reduced
Ammonia recycle percolation (ARP): aqueous ammonia passes through biomass at high temperature, after which ammonia is recovered
Performance: Strong decrystallisation of cellulose, weak removal of hemicelluloses

31. What is AFEX™? Reactor Explosion Ammonia Recovery Expansion
Recovered
vapor
Expansion
Ammonia Recovery
Biomass
Treated
Heat
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
Source: MBI
AFEX™ is a trademark of MBI

32. Biomass Conversion for Different Feedstocks Before and After AFEX
Glucan conversion for various AFEX treated Feed stocks
Switchgrass
Sugarcane
Bagasse
DDGS
Rice straw
Corn stover
Miscanthus
Glucan conversion after
enzymatic hydrolysis
UT=No Pretreatment
AFEX=Ammonia Pretreatment
Excellent Biomass Conversion After AFEX Pretreatment
Source: MBI

33. Carbon dioxide explosion
High pressure carbon dioxide, and particularly supercritical carbon dioxide is injected into the reactor and then liberated by an explosive decompression
Performance: Strong decrystalisation of cellulose, strong removal of hemicelluloses

34. Mechanical/alkaline pre-treatment
Continuous mechanical pre-treatment with the aid of an alkali
Performance: Weak removal of hemicelluloses, strong removal of lignin

35. Biological pre-treatments
White-rot fungi are the most efficient in causing lignin degradation
Source: L. Goodeve, 2003
Performance: strong removal of hemicelluloses and lignin
Source: R.A. Blanchette, 2006

36. Performance summary
Pretreatment
Decrystallization of cellulose
Removal of hemicelluloses
Removal of lignin
Inhibitor formation
Liquid hot water1) XX
Weak acid1)
Alkaline X
Organosolv
Wet oxidation
Steam explosion* 1)
Ammonia fiber explosion (AFEX)
CO2 explosion
Mechanical/alkaline
Biological
XX: Major effect; X: Minor effect;; *: increases crystallinity; 1) alters lignin structure
Inhibitors: furfural from hemicelluloses and hydroxymethylfurfural from cellulose and hemicelluloses

37. Performance summary
All pretreatments partially or totally remove hemicelluloses
Wet oxidation, AFEX and CO2 explosion reduce cellulose crystallinity
Alkaline, organosolv, wet oxidation, mechanical/alkaline and biological partially or totally remove lignin
High amounts of fermentation inhibitors are formed with liquid hot water, weak acid and steam explosion

38. Thank you for your attention