HYBRID STAGED THERMOLYSIS TO VALORISE BIOMASS Paul de Wild, March 11, 2009 Bioenergy - II: Fuels and Chemicals from Renewable Resources March 8-13, 2009, Rio de Janeiro, Brazil
INTRODUCTION Lignocellulosic biomass is a very attractive candidate for green energy carriers, chemicals and materials. Cheap and efficient fractionation technology to separate biomass into its main constituents is highly desirable. A biorefinery approach in which the fractionation is integrated with subsequent processing steps, offers the best solution for a cost-effective and environmentally sound valorisation of biomass. OBJECTIVE Proof of principle of a hybrid staged thermolysis approach for the production of furfural and levoglucosan from biomass.
SOME PRODUCTS FROM WOOD DERIVED CHEMICALS
PROCESS CONCEPT water recycle targeted at hemicellulose biomass feedstock beech water aquathermolysis aqueous filtrate furfural / hydroxymethylfurfural acetic acid lignocellulosic residue poplar hemicellulose cellulose lignin filter press residual water comminution spruce fluidisation gas fast pyrolysis char pyrolysis products levoglucosan residual bio-oil straw gas recycle targeted at cellulose
Thermal degradation mechanisms of hemicellulose and cellulose Hemicellulose Depolymerisation: trans-glycosylation but also random (radical) thermal cracking, dehydrogenation, decarboxylation, decarbonylation and various other reactions! Fengel and Wegener, 2003
EXPERIMENTAL APPROACH wood H 2 O analysis (proximate, ultimate, elements) solid residue bubbling fluidised bed pyrolysis Nitrogen Manually or screw operated feed bunker Bubbling fluidised bed reactor Freeboard Cyclone Cyclone ash collection bin Vent T [ C] autoclave volume: 0.5 l stirring, temperature T jacket T T reactor filtration, washing. drying aqeous product filtrate separation analysis organics (GC/MS/FID, IC) analysis sugars (HPLC) Argon and/or nitrogen fluidisation gas Feeding screw Heater Bubbling fluidised hot sand bed Pump Product gas sampling Heated soxhlet particle filter +40 C RT 0 t [min] t Tar sampling system consisting of 6 isopropanol filled impinger bottles, designed to trap both aerosols and condensible gas -20 C Stage 1: aquathermolysis (hot compressed water treatment) Stage 2: fast pyrolysis in a bubbling fluidised bed
PROCESS RESULTS FOR BEECH WOOD CHIPS Yield (wt%) d.b. Yield (wt% %) d.b. Yield (wt%) d.b. 12 10 8 6 4 2 0 12 10 8 6 4 2 0 12 10 8 6 4 2 0 Beech, direct pyrolysis of unmodified and dried material at 350 C M Ac HA F HMF LG PH Beech, pyrolysis at 350 C of the aquathermolysed material M Ac HA F HMF LG PH Beech, aquathermolysis of unmodified dried material at 200 C M Ac HA F HMF LG PH Aquathermolysis pyrolysis vs direct pyrolysis for beech, showing the much better yields and selectivities of the hybrid approach. M = methanol, Ac = acetic acid, HA = hydroxyacetaldehyde, F = furfural, HMF = hydroxymethylfurfural, LG = levoglucosan, PH = phenols Experiments with poplar, spruce and straw show similar results.
13 C-SS-CP/MAS NMR STUDY ON BEECH fresh dried beech lignin C 4 etherified hemicellulose C 6 hemicellulose acetyl carboxyl hemicellulose C 1 hemicellulose acetyl CH 3 aquathermolysed beech lignin C 4 unetherified pyrolysed residue from the aquathermolysis of beech
CONCLUSIONS 13 C-SS-CP/MAS NMR STUDY ON BEECH
CONCLUSIONS Proof of principle of the production of furfurals and levoglucosan from lignocellulosic biomass via a hybrid staged thermolysis approach has been delivered for deciduous (beech), coniferous (spruce) and herbaceous (straw) biomass types. Results indicate yields around 7 wt% (d.b.) for furfurals and 11 wt% (d.b.) for levoglucosan with ample potential for optimisation. Challenges are process integration and efficient separation / purification of the target chemicals from the dilute raw product mixtures. Acknowledgements This work has been conducted as part of the European Commission 6 th framework programme Integrated Project BIOSYNERGY, contract no. 038994. The financial support of the European Commission is gratefully acknowledged. Special thanks go to Dr. Ernst van Eck and Anton Lunshof of Radboud University Nijmegen, The Netherlands for the the mechanistic NMR study on beech wood
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