Thermochemical Treatment of Biomass: Carbonization and Torrefaction
David DeVallance Associate Professor, West Virginia University Research Group Leader – Renewable Materials Composites, InnoRenewCoE
Penn State, October 24, 2018
Is Wood a Conductor or Insulator?
Penn State, October 24, 2018
1 Background: Biochar and Carbon From Wood
Biochar (i.e., bio-based carbon) produced from the thermal decomposition of biomass in absence of atmospheric oxygen • The fast pyrolysis process produce a solid residue (char), liquid condensate, and gas products • Slow pyrolysis process produces biochar more suited for soil amendment applications
• Biochar Applications – For combustion – As an absorbent – Soil amendment – Catalyst development – Composite materials?
Penn State, October 24, 2018
Background: Research Biochar is typically used as a soil amendment, but has been researched for other potential uses • Fuel cell electrodes (Huggins et al. 2014) • Replacement of carbon black using corn stover biochar (Peterson 2012) • For strengthening of epoxy matrix (Ahmetli et al. 2013) • As a filler for wood plastic composites (DeVallance et al. 2015 and Nan et al. 2015) • As a filler for biodegradable packaging film (Nan and DeVallance 2014)
Penn State, October 24, 2018
2 Research Objectives The long term goal for this research effort is to develop high-quality carbon materials from woody biomass for use in composite, sensor, and energy applications The research objectives for these efforts are to: 1. Evaluate the potential electrical conductivity of carbonized wood for use in high value composites 2. Evaluate the piezoresistive behavior of bio-based carbon sensors 3. Develop highly-ordered mesoporous carbon materials for energy applications 4. Evaluate bio-based carbon as filler material in traditional wood-plastic composites (WPCs) 5. Evaluate future opportunities for carbon from wood
Penn State, October 24, 2018
Carbonization of Biomass Research Low-value Appalachian hardwoods and short rotation woody crops were carbonized at varying temperatures Species • Red Oak • Yellow-poplar • Shrub Willow • Hemp (future ?)
Carbonization • 700 oC, 800 oC, 900 oC, and 1000 oC • Tube furnace at rate of 50 oC/minute
Penn State, October 24, 2018
3 Conductivity Evaluation
Conductivity and repeat the experiments with carbonized red oak, yellow-poplar, and willow as the conducting material
• Electrical conductivity of carbonized material tested V + using two point - method
Penn State, October 24, 2018
Results: Carbonized Hardwoods BET test results indicated that as carbonization temperature increased, BET surface area increased Table 1. Brunauer–Emmett–Teller (BET) Test Results Pores at macro-scale:
Red Oak HTT=700Ԩ
Yellow poplar HTT=700Ԩ
BET of commercial hardwood biochar = 45.4 m2/g
Penn State, October 24, 2018
4 Results: Carbonized Hardwoods Proximate analysis test results show that carbonized material had a higher carbon content than commercial biochar Table 2. Fixed Carbon (Proximate Analysis) Test Results
Penn State, October 24, 2018
Results: Conductivity Red oak biochar Increase in HTT resulted in an increase in conductivity Increase in density (or pressure) resulted in an increase in conductivity
Yellow-poplar biochar Willow biochar
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5 Results: Capacitance Red oak biochar Willow biochar showed the highest capacitance Increase in pyrolysis temperature appeared to only improve capacitance in red oak
Yellow-poplar biochar Willow biochar
Penn State, October 24, 2018
Development of Biomass-Based Piezoresistive Sensors PVA/biochar piezoresistive sensors were film casted and tested with a TA Q800 dynamic mechanical analysis system
Figure 1. (a) Schematic of the piezoresistive sensor test setup, (b) DMA setup for PVA/biochar pressure sensor test; (c) Circuit used for piezoresistive sensor testing.
Penn State, October 24, 2018
6 Results: PVA/Biochar Sensors
The percolation threshold of the PVA/biochar composites was 16wt%.
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Results: PVA/Biochar Sensors 6wt% biochar content were the most linear sensor Piezoresistive behavior of PVA/biochar films at (a) red oak different biochar content (room temperature).
(b) yellow-poplar (c) willow
Penn State, October 24, 2018
7 Highly Ordered Mesoporous Carbon Research Experimental process involves slowly heating in air at temperatures below 250 °C, oxidation (under limited oxygen) at temperatures below 400 °C, then further carbonization
Research Team: J. Wang, X. Xie, D. DeVallance, E. Sabolsky, and J. Zondlo
Penn State, October 24, 2018
Wood/Biochar/Plastic Composites Research Combinations of wood, biochar, torrefied wood, and polymers have been investigated to improve mechanical, thermal, and physical property improvement
PP Matrix Embedded in Biochar Particles
Biochar Particles
Penn State, October 24, 2018
8 Wood Pellet Research
Red Oak and Willow were torrefied at 250 oC and 300 oC for 30 minutes using a pilot-scale torrefaction unit at WVU
Particle Size
Sieve 0.5-0.7 mm 1mm 0.7-1.0 mm screen Condition
385 oF at 1,000 lbf MC for 3 min. 1.5 % 5.0%
Penn State, October 24, 2018
Questions? Funding for these research projects by: USDA/NIFA Wood Utilization Research Program USDA/NIFA McIntire-Stennis Program, Project WVA00116 USDA/NIFA Agriculture and Food Research Initiative (AFRI) Programs
Biomaterials and Wood Utilization Research Center (http://www.wdscapps.caf.wvu.edu/BioMatWURCtr) http://forestry.wvu.edu/faculty_staff/david_devallance
Penn State, October 24, 2018
9 References
Ahmetli, G., S. Kocaman, I. Ozaytekin, and P. Bozkurt. 2013. Epoxy Composites Based on Inexpensive Char Filler Obtained from Plastic Waste and Natural Resources.Polymer Composites 34 (4): 500–509. DeVallance, D.B., G.S. Oporto, and P. Quigley. 2014. Thermal, mechanical, and physical properties of wood-plastic composites with added biochar. Journal of Biobased Materials and Bioenergy. Huggins, T., H. Wang, J. Kearns, P. Jenkins, and Z. J. Ren. 2014. Biochar as a Sustainable Electrode Material for Electricity Production in Microbial Fuel Cells. Bioresource Technology 157 (April): 114– 19. Nan, N.*, D.B. DeVallance, X. Xie, and J. Wang. 2015. The effect of bio-carbon addition on the electrical conductive, mechanical, and thermal properties of polyvinyl alcohol/biochar composites. Journal of Composite Materials. Advance online publication. doi:10.1177/0021998315589770. Nan, N. and D. DeVallance. 2014. Bio-based Carbon/Polyvinyl Alcohol Composite Materials. Poster presented at the 2014 Bioelectronics and Biosensing International Symposium, Morgantown, WV, April 27-28. Peterson, S. 2012. Evaluating Corn Starch and Corn Stover Biochar as Renewable Filler in Carboxylated Styrene–butadiene Rubber Composites. Journal of Elastomers and Plastics 44 (1): 43– 54.
Penn State, October 24, 2018
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