LIBRA: a lignin biorefinery approach for enhanced profitability

Transcription

1 LIBRA: a lignin biorefinery approach for enhanced profitability P.J. de Wild March 2014 ECN-L

2 LIBRA: a lignin biorefinery approach for enhanced profitability Paul de Wild

3 Main fractions lignocellulosic biomass Deciduous woods 1 ( hardwoods e.g. beech, poplar,..) 41-49% cellulose 24-34% hemicellulose Coniferous woods 1 ( softwoods e.g. spruce, pine, ) 41-51% cellulose 12-24% hemicellulose Herbaceous crops 2 ( grasses e.g. straws, grass, corn stover,.) 27-39% cellulose 20-34% hemicellulose 20-26% lignin (syringyl & guaiacyl units) 27-33% lignin (mainly guaiacyl units) 1. D. Fengel and G. Wegener, Wood, Chemistry, Ultrastructure and Reactions. Verlag Kessel D. Lee et al., Composition of Herbaceous Biomass Feedstocks. North Central Sun Grant Center, South Dakota State University. SGINC1-07, June % lignin (p-hydroxyphenyl, guaiacyl & syringyl units)

4 Lignin: structure, function and use Lignin is a complex and recalcitrant phenolic biopolymer that provides structural rigidity, flexibility and microbial protection in lignocellulosic biomass. Wood vessels Cell wall structure Hemicellulose Fibres Lignin is an abundant side stream from the pulp & paper industry and biorefineries and a source for renewable aromatics. Tree trunk Cellulose Lignin is mainly used as low-value fuel for heat and power while there is a strong need for a cost-effective conversion into valuable products for profitable biorefineries. Extractives Lignin A dedicated pyrolysis technology was developed by ECN to convert lignin in biophenolics and biochar useful for a variety of value-added applications. Per Hoffmann, Oskar Faix and Ralph Lehnen Holladay et al., Top value added chemicals from biomass. Volume II Results of screening for potential candidates from biorefinery lignin. Produced by the staff at the Pacific Northwest National Laboratory (PNNL) and the National Renewable Energy laboratory (NREL) (2007). Zakzeski, J., Bruijnincx, P.C.A., Jongerius, A.L., Weckhuysen, B.M., The Catalytic Valorization of Lignin for the Production of Renewable Chemicals. Chem. Rev. 110 (2010) P.J. de Wild, H. Reith, H.J. Heeres, Biomass pyrolysis for chemicals, Biofuels. 2 (2), (2011)

5 Simplified lignin structure hardwood Most bonds are of the β-o-4 type (> 50%). Most internal bonds via the para position. Variety of other bonds (ether, ester, -C-C-,..). Heterogeneous and recalcitrant structure. coumaryl-unit Guaiacyl, syringyl and coumaryl moieties are basic structural units. guaiacylunit H. Nimz, Beech lignin Proposal of a constitutional scheme. Angew. Chem. Internat. Edit., Vol. 13, No. 5, pp , 1974 syringyl-unit

6 Some desirable chemicals from lignin Methanol Benzene, toluene, xylenes (BTX) Styrene Phenol and alkylated phenols Methoxylated phenols Catechols H. Nimz, Beech lignin Proposal of a constitutional scheme. Angew. Chem. Internat. Edit., Vol. 13, No. 5, pp , 1974

7 Applications for lignin and lignin pyrolysis products oligomeric fragments from the pyrolysis of lignin low volume - high value market /t specialty chemicals bio-plastics bio-resins for wood-adhesives alkylphenols additives for flooring material activated carbon, carbon-fibres and carbon-black fuel-additives guaiacols OH catechols O OH OH OH OH OH bio-bitumen for green asphalt bio-char for soil improvement syringols O OH O OH O O OH O O OH bio-fuel for CHP O O O O O O O O OH OH OH OH monomeric phenols from the pyrolysis of lignin high volume - low value market 100 /t

8 Lignocellulose biorefinery Organosolv fractionation and pyrolytic lignin valorisation Lignocellulosic biomass Water+solvent + catalyst Primary biorefinery Organosolv fractionation Solvent separation Paper & cellulosic materials Cellulose Hemicellulose Secondary biorefinery (Enzymatic) hydrolysis Biochemical conversion (fermentation) Chemical conversion Ethanol Butanol Lactic acid Xylitol Furfural HMF Lignin separation and purification Lignin Pyrolysis Bio-oil & char recovery Phenolics Fuel additives Char Filler, adhesives, etc. Combined heat & power Electricity Heat

9 Lignin valorisation options in a lignocellulosic biorefinery for bio-ethanol Lignocellulosic biomass Lignin LIBRA Bio-EtOH Pretreatment DDB Pretreatment Hydrolysis Feeding Fermentation Pyrolysis Distillation, purification Distillation residue Product recovery Biophenols Biochar Lignin extraction Drying Dried distilled biomass Char and/or oil Combustion Lignin Heat & power P.J. de Wild, H. Reith, H.J. Heeres, Biomass pyrolysis for chemicals, Biofuels. 2 (2), (2011)

10 LIBRA: Lignin BioRefinery Approach

11 ECN: Organosolv fractionation ECN: lignin valorisation by pyrolysis and catalytic oxidation

12 Incentive to pyrolyse lignin Methods for the conversion and application of lignin other than simply burning it for the production of heat are generally lacking. A major effort is therefore needed to develop new technology for lignin valorization by converting it, at least partly, to value-added chemicals. Zakzeski J, Bruijnincx PC, Jongerius AL, Weckhuysen BM, The catalytic valorization of lignin for the production of renewable chemicals. Chem Rev Jun 9;110(6): A myriad of conversion technologies for lignin exists (including pyrolysis), but none of them are economically feasible due to their complexity. ECN has developed LIBRA: a simple and effective lignin pyrolysis technology that produces ~20% gas, ~45% oil and ~35% char. The oil is a complex mixture of high-value- monomeric phenolics, undefined oligophenols, water and small amounts of low-boiling components. What can we do with it? Is it valuable? Projects? Industrial interest?

13 Lab-scale lignin pyrolysis experiments Feedstocks CIMV straw lignin Kraft softwood lignin Alcell hardwood lignin Test facilities Bubbling fluidised bed reactor (1 atm.,1 kg/hr (max), 5 kw th ) Fractionated product sampling, on-line gas analysis by ND-IR (CO, CO 2, CH 4 ), off-line analysis by GC/MS/FID, Karl-Fischer (water) and gravimetry Comparative tests different lignins 150 g dry feedstock with 10 wt% additive X 500 C, 8 sec vapour residence time

14 Pyrolysis reactor set-up 1 kg/hr bubbling fluidised bed Reactor Cyclone & particle filter Products Gas conditioning & analysis (CO, CO 2, C x H y ) Batch sampling with impinger train Off-gas Off-gas Lignin feed Ash Continuous sampling with condensers, ESP and filters in series Off-gas Reactor feeding screw Hot sand bed 500 C Lignin biochar Lignin bio-oil Pre-heated fluidisation gas

15 Comparative pyrolysis results Major product fractions and lignin pyrolysis oil composition Mass balance closure ~ 95% wt% pyrolysis gas (CO 2, CO, CH 4 ) wt% lignin pyrolysis oil (LPO) wt% phenolics (Alcell>Kraft> Biolignin) differences due to oligomeric fraction 5-7 wt% monomers, wt% oligomers Compositional differences attributable to differences in lignin wt% biochar

16 Lignin pyrolysis oil from pure Biolignin Lignin pyrolysis oil is usable for e.g. resins, biochar can be used as soil improver or as precursor for carbon-black and active carbon Ultimate analysis results dry oil: Heating value ~31 MJ/kg 70% C, 20% O, 8% H, 2% N Negligible ash content Pyrolysis oil composition: Complex bio-oil composition Various phenolic monomers, guaiacols, alkylphenols and catechols are the major phenols The unidentified oligomeric phenols constitute the major fraction Acetic acid is the main non-phenolic organic (~1.6 wt% based on lignin)

17 Economic margin analysis lignin pyrolysis Economic margin = Product value Feedstock costs Lignin pyrolysis products pyrolysis oil = 1200 /t (phenol) lignin char = 1000 /t (½ activated carbon) lignin pyrolysis gas = 150 /t (½ methane price) Lignin feedstock costs = /t (organosolv lignin) Mass balance 23 (water) Economic margin > 0 when lignin production costs < 700 /t

18 Conclusions / outlook Lignin valorisation is a key-issue for a profitable biorefinery. Lignin can be pyrolysed into a complex phenolic bio-oil and biochar. The complex bio-oil contains monomeric and oligomeric phenolics. The recovery of high-value phenols from lignin oil is a challenge but the oil as such can be used to substitute phenol in various applications. Pyrolytic valorisation of lignin can have economic potential. The challenge is to increase the phenolics yield and to identify / develop valorisation for the char. Major strength of LIBRA is the relatively simple and robust pyrolysis technology. Investments needed for scale-up!

19 Thank you for your attention! The work presented is performed within: the 7 th framework Integrated Project BIOCORE The Dutch CatchBio SmartMix Lignin cluster ECN Westerduinweg 3 P.O. Box LE Petten 1755 ZG Petten The Netherlands The Netherlands T F info@ecn.nl The support of the European Commission and the SMART MIX program of the Netherlands Ministries of Economic Affairs and Education, Culture and Science is gratefully acknowledged.

20 Questions?

21 ECN Westerduinweg 3 P.O. Box LE Petten 1755 LG Petten The Netherlands The Netherlands T F info@ ecn.nl 8