Fast pyrolysis of guayule shrub and bagasse Colleen McMahan 1, Kwesi Boateng 2, Charles Mullin 2 Katrina Cornish 3

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1 Fast pyrolysis of guayule shrub and bagasse Colleen McMahan, Kwesi Boateng 2, Charles Mullin 2 Katrina Cornish 3 United States Department of Agriculture Agricultural Research Service Western Regional Research Laboratory Albany, CA USA 2 Eastern Regional Research Center Wyndmoor, PA USA 3 Yulex Corporation, Maricopa, AZ USA (former) The Ohio State University, OARDC Wooster OH, USA EU-PEARLS October 4-5, 200 Montpellier, France

2 ARS National Programs NP 306 Quality and Utilization of Agricultural Products Domestic Natural Rubber Develop commercially-viable natural rubber-producing crops suitable for cultivation in the temperate climate of the USA. NP 23 Bioenergy & Energy Alternatives Thermochemical Conversion Develop technology for sustainable exploitation of energy from agriculture.

3 Guayule: a source of domestic natural rubber Parthenium argentatum, guayule, is a woody desert shrub native to the SW USA now under cultivation (~5000 acres) in Arizona, USA. Aqueous process extracts rubber in latex form. Guayule latex (GNRL) is an alternative natural rubber latex suitable for the manufacture of latex medical products safe for people with Type I IgE-mediated Hevea latex allergies. Keys to sustainability: biobased co-products biotechnology bioenergy

4 Guayule bagasse: a bioenergy feedstock Latex extraction leaves 80-90% of the crop biomass as a finely-divided, free flowing feedstock suitable for conversion to biofuels.. Finely divided dry solid 2. Ag and harvest costs borne by rubber production 3. High density 4. High energy content 5. Flexible feedstock for biochemical and thermochemical processes 6. Harvested 2 months/year Other 80% Rubber 0% Resin 0%

5 The guayule biorefinery: bioproducts + bioenergy GUAYULE SHRUB LATEX Rubber as cis-,4- polyisoprene RESIN Recoverable and useful mixture of terpenoids, fatty acids GUAYULE BAGASSE = BIOENERGY FEEDSTOCK Fermentation Pyrolysis Gasification Combustion ETHANOL BIO-OIL SYNGAS ELECTRICITY LIQUID FUEL

6 Fast pyrolysis process 3 products. bio-oil (60-75% wt.) 2. char (5-20% wt.) 3. non-condensable gases (0-20% wt.) Boateng et al. Ind. Eng. Chem. Res. 46:89-7 (2007)

7 Bio-oil is A dark brown, free flowing liquid consisting of over 00 compounds, produced from the pyrolytic decomposition of biomass. An alternative fuel with a smoky odor reminiscent of the plant from which it was derived. A liquid chemical intermediate as a very complex mixture of oxygenated hydrocarbons that can be further purified or converted into industrial chemicals and vehicle fuels. A micro-emulsion. It contains up to 25% emulsified water from both original moisture and reaction product. It does not mix with hydrocarbon liquids. ~Analogous to asphaltenes found in petroleum. Also referred to as crude pyrolysis liquid, pyrolysis fluid, or pyrolysis liquid fuel intermediate. Photo:

8 Objectives Determine the feasibility of thermochemical conversion by fast pyrolysis of guayule bagasse. Compare fast pyrolysis of guayule bagasse to other bio-feedstocks. Provide engineering parameters for bio-refinery design.

9 Materials and Methods Guayule Whole shrub (mature, AZ-2 variety) Maricopa, AZ (December, 2007) Bagasse from commercial production finely-divided dry solid from defoliated, latex extracted shrubs (G4) Dried at 60 C for 24 h Ground in a Wiley mill using a 2-mm screen (#0 US Mesh) Whole shrub (G), with rubber extracted (G2), rubber and resin extracted (G3) Process Biomass pyrolysis GC-MS (Pyroprobe 2000 CDS Analytical, Oxford, PA) Bench scale fluidized bed pyrolysis reactor Kwesinator Analysis Biomass proximate and ultimate analysis per ASTM D529, XRF and mineral content of ash (ASTM D4326) (Wyoming Analytical Laboratories, Inc. Laramie, WY). Cell wall composition (cellulose, hemicellulose, and lignin) from the USDA- ARS (St. Paul, MN) using methods described by Dien et al

10 Results: Gross calorific values cal/g G G2 G3 G4 A.A. Boateng et al. / J. Anal. Appl. Pyrolysis 87 (200)

11 Fast pyrolysis products identified by GC-MS Benzene 2 Hydroxyacetaldehyde 3 Acetic acid 4 Acetol 5 Toluene 6 Ethyl benzene 7 p-xylene 8 o-xylene 9 Styrene 0 Furfural Ethylmethyl benzene 2 Trimethyl benzene 3 Limonene 4 Indane 5 Indene 6 Butenyl benzene ketones, aldehydes 0.2% esters, carboxylic acids 0.4% aromatics, olefins 43.5% A.A. Boateng et al. / J. Anal. Appl. Pyrolysis 87 (200) Hydroxy-3-methyl-2-cyclopenten--one 8 Phenol 9 2-Methyoxyphenol (guiaicol) 20 o-cresol 2 Naphthlene short aliphatics 9.% 22 m-cresol 23 p-cresol 24 2-Methoxy-4-methyl phenol 25 Dimethyl phenola Phenol long, branched 26 Methyl naphthalenea aliphatics 27 2-Methyoxy-4-vinyl 29.0% phenol 28 Dimethyl naphthalenea % 2,6-Dimethoxyphenol (syringol) 30 Isoeugenol 3 Hydroquinone 32 Levoglucosan 33 4-(2-Propenyl)-2,6-dimethoxy phenol alcohols, ethers, phenolic-methoxys, carbohydrates sugars

12 Results: Guayule biomass characterization Property Method Whole shrub bagasse Moisture (% as rec d) weight loss Ash (%dw) weight loss after combustion at 450 C /6 h muffle furnace C (%dw) ASTM D H (%dw) ASTM D N (%dw) ASTM D S (%dw) O (%dw) ASTM D529 (difference) Cellulose (%dw) Cell wall glucose HPLC Hemicellulose (%dw) Σ (cell wall xylose, arabinose, mannose, uronic acids) 2 Lignin (%dw) acid-insoluble residue after correction for ash HHV (kj/kg) 8,329 22,385 Wyoming Analytical Laboratories, Laramie, Wyoming 2 Analysis by Hans-Joachim Jung following Dien et al. Biomass Bioenergy 30:880 (2006.)

13 Bio-Oil & Bio-Char ERRC

14 Kwesinator Process Conditions Guayule Bagasse Bagasse Whole Whole Run date 2/4/2007 2/9/2007 2/0/2007 2/3/2007 Operational conditions Biomass [g] Feed rate [g/hr] Bed temp. [ C] Condenser # temp. [ C] Condenser #3 temp. [ C] Condenser #4 temp. [ C] ESP temp. [ C] Heat rate [ C/s] Total quench rate [- C/s] Boateng et al. Fuel 88 (2009)

15 Pyrolysis Results: Guayule Bio-oil! Feed auger was chilled with dry ice to stay at below 50 C. Reaction time less than 0 seconds. Guayule bio-oil collected primarily at electrostatic precipitator. Duplicate runs performed with remarkably consistent results (whole shrub and bagasse). Bio-oil produced from guayule (~400 grams under each condition) remarkably higher in viscosity compared to other feedstocks. Boateng, ERRC Dec 2007 Bio-oil from guayule

16 Guayule pyrolysis: product yields Whole, dry basis H2 0% CH4 2% CO2 43% % Biomass Bagasse Whole CO 35% Bagasse, dry basis Pyrolysis Oil Charcoal NCG H2 % CH4 5% CO2 25% CO 49% 60% of biomass was converted to pyrolysis fluid Higher charcoal in whole shrub due to ash content Lower CO2 in bagasse syngas

17 Results: Guayule bio-oil characterization property ASTM method Whole shrub Bagasse Elemental Analysis (wt %, dry basis) Average of the two bio-oils produced for each feedstock. C D H D N D S D O D529 (difference) Water, % Karl-Fisher titration Fuel Properties HHV (kj/kg, wet basis) 30,428 30,508 Density (g/ml) D Flashpoint ( C) D93B >20 >20 60 C (cst) Kinematic viscosity ASTM D445 Wyoming Analytical Laboratories, Laramie, Wyoming 2 Galbraith Laboratories, Knoxville, TN

18 Guayule charcoal by-product property ASTM method Whole shrub Bagasse C D H D N D S D O D529 (difference) Ash D Fuel Properties HHV (kj/kg, wet basis) 5,274 24,892 Char is useful for energy production, for soil enhancement and carbon sequestration

19 Fast Pyrolysis Product Yields

20 Bio-oil Analysis ARS Oak Chicken Litter Guayule Barley Straw Corn Stover Ryegrass Switchgrass Alfalfa stems Soybean straw ESP Fraction % Water Condenser Fraction % Water N/A Total % Water Organic C:O Ratio.95: 3.37: 4.36:.55:.99:.33:.80: 2.43:.53: HHV (MJ/kg), wet HHV (MJ/lkg), dry ph

21 Fast pyrolysis of guayule: efficiency Energy recovery efficiency Bio-oil Bio-oil + Char Whole Bagasse Bio-oil + Char + NCG aincludes coke and unrecovered liquid product trapped in the system. bncg = non condensable 0 gas Energy recovery (% of input)

22 Summary Guayule bagasse and whole shrub material was successfully converted into bio-oil, charcoal, and non-condensable gases by fast pyrolysis at ~ 500 C in a bench-scale fluidized bed reactor. Yields ~ 60% (comparable to switchgrass) were demonstrated in pilot scale. Bio-oils from guayule pyrolysis had energy content higher than that of typical fast pyrolysis oil, about 30 MJ/kg, 75% the value of heavy fuel oil. NCG produced are sufficient in providing all needed energy input. Mass/energy balance determined for economic/design studies. Overall compares equally or favorably to energy crops. Compositional analysis of feedstocks and of the bio-oil suggest guayule is a very attractive feedstock for fast pyrolysis and subsequent conversion processes. Thermochemical conversion produces bioenergy while consuming the entire plant, significantly improving the value proposition for profitable and sustainable growth of domestic rubber in the USA.

23 Thank you Yulex Corporation Charles Mullin, USDA/ARS, ERRC Hans-Joachim Jung, USDA-ARS Plant Science Research Unit (St. Paul, MN) Wyoming Analytical Laboratories, Laramie, Wyoming Alex Arceneaux, USDA/ARS, WRRC Galbraith Laboratories, Knoxville, TN