1. Pre-treatment Technologies
Jean-Luc Wertz and Prof. Michel Paquot
Lignofuels September 2011

2. PLAN Introduction Physical pre-treatments
Chemical pre-treatments (e.g. organosolv)
Physicochemical pre-treatments (e.g. steam explosion; AFEX)
Biological pre-treatments
Economic analysis (OPEX, CAPEX)
Performance summary

3. Average composition of lignocellulosic biomass

4. Cellulose: molecular structure
Glucose units linked by β 1-4 glycosidic bonds
One reducing end and one non-reducing end
Linear straight polysaccharide

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

6. Lignin
Monomers : 3 different monolignols (H, hydroxyphenyl; G, guaïacyl; S, syringyl) H G S

7. Lignin
Cross-linked polymers of monolignols

8. Schematic of the role of pre-treatment
Source: P. Kumar et al., 2009

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

10. Inbicon’s hydrothermal pre-treatment pilot plant

11. 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

12. Alkaline hydrolysis
Well known in the pulp and paper industry as kraft pulping

13. Extraction of lignin from Kraft pulp mill black liquor by the LignoBoost process
Source: Metso, LignoBoost

14. Schematic of the MixAlco® process (Terrabon, Inc.)
Source: Holtzapple et al., Terrabon

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

16. 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

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

18. CIMV process: formic acid / acetic acid / H2O
lignocellulosic materials
Formic Ac./Acetic Ac./Water
heating
filtration
black liquors
pulp
Formic Ac./Acetic Ac./Water
rinsing
black liquors
Water
pulp
water precipitation
Water
washing
centrifugation
Water solubles
pulp
lignins
Acidified water
Source: C. Vanderghem et al., ULg-GxABT
washing
lignins

19. CIMV process using acetic acid/formic acid/water
Source: C. Vanderghem et al., ULg-GxABT ,
Time: 1h (-1), 2h (0), 3h(1). Temperature: 80°C (-1), 90°C (0), 107°C (1)

20. CIMV process using acetic acid/formic acid/water
Source: C. Vanderghem et al., ULg-GxABT
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)

21. CIMV process using acetic acid/formic acid/water
Source: C. Vanderghem et al., ULg-GxABT
Time: 1h (-1), 2h (0), 3h(1). Temperature: 80°C (-1), 90°C (0), 107°C (1)

22. CIMV process using acetic acid/formic acid/water
Source: C. Vanderghem et al., ULg-GxABT
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)

23. Oxidative delignification
Hydrogen peroxide treatment
Ozone treatment
Wet oxidation: treatment with oxygen or air in combination with water at high temperature and pressure

24. Room temperature ionic liquids
Main cations and anions in ionic liquids

25. Room temperature ionic liquids
Different types of interaction present in imidazolinium-based ionic liquids

26. Room temperature ionic liquids
Proposed mechanism for cellulose dissolution in EmimAc

27. Room temperature ionic liquids
Hydrolysis of cellulose in a mixture of cellulases and an ionic liquid (HEMA) +

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

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

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

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

32. 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

33. 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
AFEX™ is a trademark of MBI

34. 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

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

36. Mechanical/alkaline pre-treatment
Continuous mechanical pre-treatment with the aid of an alkali

37. Biological pre-treatments
White-rot fungi are the most efficient in causing lignin degradation
Source: L. Goodeve, 2003
Source: R.A. Blanchette, 2006

38. Performance summary
Pretreatment
Decrystallization of cellulose
Removal of hemicelluloses
Removal of lignin
Inhibitor formation
Liquid hot water1) XX
Weak acid1)
Alkaline X
Organosolv X3
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

39. 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

40. ECONOMIC ANALYSIS: OPEX (Minimum Ethanol Selling Price), CAPEX
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
Ammonia recycle percolation (ARP)
4.56
Ideal
1.00
2.51
Source: Eggeman et al., 2005
NB Enzyme cost: EUR 3/kg of produced cellobiose

41. Thank you for your attention