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Development of fast microwave-assisted pyrolysis and gasification processes for efficient conversion of biomass into bio-oil, bio-char, and syngas, with improved yields and product quality.
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Development of Novel Fast Pyrolysis and Gasification Processes Roger Ruan, Professor and Director Paul Chen, Associate Research Professor and Program Director Qinglong Xie, Shiyu Liu, Bo Zhang, Peng Peng, Erik Anderson, Yanling Cheng, Yuhuan Liu, Min Min, Nonso Onuma Center for Biorefining and Department of Biosystems and Bioproducts Engineering
Pyrolysis http://www.cleansolutionsco.com/technology.html • High temperature (400-700 ºC), no oxygen • Biomass is thermally decomposed to bio-oil (liquid), bio-char (solid), and syngas (gas)
Gasfication http://www.cleansolutionsco.com/technology.html • Very high temperature (800-1100 ºC), restricted oxygen addition • Biomass is mainly converted to gas, with a little tar and char
Problems of conventional pyrolysis and gasification technologies Use high volumes of carrier gas and the gas product is diluted Need fluidization and many particles and impurities are in the products Consume a lot of energy
Microwave based technologies • Uniform internal heating of biomass particles • Easy to control • No need for agitation of fluidization • Syngas has higher heating value since it is not diluted by the carrying gas • Mature technology and low cost • Highly scalable technology suitable for distributed conversion of bulky biomass
Heat flux Mass flux Microwave energy Mass flux Heat flux b. Microwave heating approach a. conventional heating approach c. Pyrolysis front development with conventional heating d. Pyrolysis front development with microwave heating
Fast microwave-assisted pyrolysis (fMAP) and gasification (fMAG) • Use of microwave absorbents • Makes fMAP and fMAG feasible • Helps overcome some of the drawbacks associated with fluidized bed processes • Achieves higher yield and better product quality • Further enhances all the unique characteristics and quality of the MAP.
Overall goal • To develop novel fast microwave-assisted pyrolysis (fMAP) and gasification (fMAG) processes for distributed conversion of solid residues, obtaining fuels and chemical building blocks for synthesis of other useful chemicals.
Specific objectives • Screen the microwave absorbents • Develop novel microwave based system • Investigate the effects of key parameters on products yield and quality • Optimize fMAP and fMAG processes • Continuous microwave-assisted biomass conversion system
Feedstock a Calculated by difference, O (%) =100-C-H-N-Ash
Micorwave absorbent screening Ability of a specific material to absorb microwave energy and convert it into heat Dielectric properties of the material tan = / describes the overall efficiency of a material to absorb microwave radiation • high (tan > 0.5) • medium (0.1–0.5) • low (<0.1)
Micorwave absorbent screening a Activated carbon at a mean temperature of 398 K. • good microwave absorbents • large commercial availability with low cost • easyrecycle and reuse
FMAP: Experimental design • 23 factorial CCD + 3 repetitions of the central point = 11 experiments • Independent variables • temperature (x1, ⁰C) • feedstock loading (x2, g) • bed particle size (x3, grit) • Dependent output variables • yields of liquid fraction (y1, %), gas fraction (y2, %) and char (y3, %), the moisture content (y4, %) and yield of syngas (y5, %).
fMAP: Effects of key parameters 65% of liquid phase • 500 ⁰C, 30 grit SiC, 3g/min of biomass loading
fMAP: Effects of key parameters Temperature Bed particle size x biomass loading
Temperature X Feedstock loading • Intermediate temperature and low feedstock loading favor the fMAP process
Temperature X Bed particle size • Intermediate particle size (30 grit) of microwave absorbents favors the fMAP process
Feedstock loading x Bed particle size • Low feedstock loading • Intermediate particle size of microwave absorbents
fMAP: Bio-oil properties a Calculated using the equation HHV (MJ/kg) = (3.55xC2-232xC-2230xH+51.2xCxH +131xN+20,600)x10-3
Issues of typical biomass materials Lignocellulosic biomass is a hydrogen-deficient feedstock. A parameter called hydrogen to carbon effective ratio (H/Ceff) is used to reflect the relative hydrogen content of different feedstocks. • The H/Ceff ratio of biomass and biomass-derived feedstocks is only 0-0.3. Solutions • The content of CH in bio-oil could be promoted by increasing the H/Ceff ratio in feeds.
Solutions Saturated Monohydric Alcohols (H/Ceff=2),Waste Grease (H/Ceff=~1.5) and scum can also function as hydrogen sources and be co-fed with biomass to improve the overall H/Ceff ratio. High Density Polyethylene (HDPE，H/Ceff=2) HDPE Methanol Waste Grease
Innovative Reactor Development Catalyst Biomass Catalyst
Fast microwave-assisted gasification (fMAG) • Feedstock: corn stover • Temperature: 900 oC • Catalyst: Fe/Al2O3, Co/Al2O3, Ni/Al2O3
Conclusions and future work • A bench scale system for fMAP and fMAG has been developed. • The use of microwave absorbents makes microwave heating much more efficient. • The effects of various parameters on fMAP and fMAG processes have been examined. • Continuous microwave based fast pyrolysis and gasification system are under development.
Acknowledgments: Related Group Members and Collaborators: B. Polta, J. Willett, A. Sealock, R. Hemmingsen, P. Chen, M. Min, W. Zhou, M. Mohr, Y. Chen, L. Wang, Yecong Li, Bing Hu, Q. Kong, X. Wang, Y. Wan, K. Hennessy, Y. Liu, X. Lin, Yun Li, Y. Cheng, S. Deng, Q. Chen, C. Wang, Y. Wang, Z. Du, X. Lu, Z. Wang, R. Griffith, J. Thissen, Q. Xie, Y. Nie, F. Borge, F. Hussain, Y. Jiang, Y. Sun, Z. Fu, R. Zhu, A. Olson, B. Martinez, B. Zhang, J. Zhu, B. Hu, L. Schmidt, D. Kittelson, R. Morey, D. Tiffany, F. Yu, H. Lei, X. Ye, M. Muthukumarappan, P. Heyerdahl, …… Funding Agencies:
