Petter H. Heyerdahl, Associate Professor
Department of Mathematical Sciences and Technology Norwegian University of Life Sciences (UMB)
and
R. Roger Ruan, Professor and Director Center for Biorefining
Department of Bioproducts & Biosystems Engineering University of Minnesota (UMN)
Hydrothermal Treatment and
Microwave Assisted Pyrolysis of Biomass For Bio-fuel Production – Progress Report
Hydrothermal Treatment and Hydrothermal Treatment and Microwave Assisted
Microwave Assisted Pyrolysis Pyrolysis of Biomass of Biomass For Bio
For Bio - - fuel Production fuel Production – – Progress Report Progress Report
Outline
• Background - distributed generation and biorefining
• Hydrothermal process
• Microwave assisted pyrolysis
• Conclusions
New Approach/Thinking/Concept
Distributed Conversion/Generation
Biomass
Transport Central Processing Facility (CPF)
On-Site or Mobile Processing
Facility (OMPF) Products
Densified Chemical Feedstock (DCF)
Bulk Biomass
Fractionation
& Conversion
Refining
Biorefining Approach
Corn Refining
Stover
Fermentation
Ethanol DDGS
Feed
CONVERSION
Bio-oils Syngas Ashes
Energy Fuel
Animals
Wastes
Ammonia Fertilizers
Germ Starch
Bio-diesel Oil
On-Site or Mobile
Thermochemical Conversion
• Hydrothermal process
• Microwave assisted pyrolysis
• Total liquefaction
Hydrothermal Treatment
• Advantages
– No need to dry the sample since water is the solvent
– No need of additional solvents for liquefaction – Fast reaction rate
– No need for large scale system installation – Feedstock: high moisture content solids
including agricultural and forest
wastes/residues, municipal waste water
treatment sludge, municipal solid wastes
Hydrothermal Process:
High pressure liquefaction system
Liquefied bio-crude
Oil-phase
Water-phase
Continuous Hydrothermal System
Pressure: <5,000 psig, Temperature: ~375 °C, Flow rate: 10-60 ml/min.
Hydrothermal Process
Liquefaction yield as a function of potassium hydroxide content (Liquefaction time 10 minutes, 10% corncob, temperature 375°C.) Error bars represent standard deviations calculated from the data obtained from 3 duplicated experiments.
0 20 40 60 80 100
1 5 10 15
KOH (%)
Yield (%)
Gas phase Liquid phase
Residues Total
Temperature (°C) Init N2 Press. %Collected %Char %Oil
280 0 90.1 44.8 16.6
300 0 90.9 40.3 20.6
320 0 90.8 43.l9 13.7
340 0 90.5 37 22.3
Temperature (°C) Init N2 Press. %Collected %Char %Oil
280 500 92.6 40.3 26.0
300 500 93.3 35.4 30.0
320 500 91.3 32.2 40.0
340 500 92.1 29.4 46.1
350 500 93.7 33.2 31.7
360 500 92.0 25.4 42.8
365 500 92.7 23.4 29.5
380 500 91.8 25.2 33.3
Effect of temperature and process gas on yield of hydrothermal treatment
Hydrothermal Process
GC-MS chromatograms of the liquid obtained from corncob liquefaction.
(Liquefaction time 10 minutes, corncob content 10%, no catalyst, temperature 300°C, 325°C, 350°C, and 375°C).
Hydrothermal Process
• The gas phase was 33 -45% (wt%), the liquid phase 22 - 45% (wt%), and solid phase 10 - 28% (wt%) at 5 - 20
minutes. The gas products are mainly composed of hydrogen, carbon monoxide, carbon dioxide and
methane, and small amount of C2-C4 hydrocarbon. The gas can be used as syngas or further reformed to
produce DME or other products.
• The major components of the liquid products are
polycyclic aromatic hydrocarbons, ketones, aldehydes, carboxylic acids, esters, nitrogenated compounds, and related derived compounds. From an industrial point of view, some aromatic compounds such as phenol,
benzene and furan were obtained in a high proportion.
The liquid phase can be used either directly as fuel, or as feedstock for further chemical refining process,
opening the door of possibilities for biomass utilization.
Microwave Assisted Pyrolysis
PYROLYSIS: Braking Down (LYSIS) of a Material by Heat (PYRO)
Biomass is heated to 300 - 600 ºC
in the absence
of air in a gas thight
reaction chamber.
Biomass input
Gases CO, CO2 , H2 , CH4
Liquids
Microwave energy
input
Vola- tiles
Char/Carbon
and other inert solid material
Condenser
Heating Methods
Low
temperature inside
External heat source.
Must be warmer than material to be heated
Traditional heating
Gases flow against
heat flow
Microwaves
Microwave heating
Gases flow same way
as the heat
High temperature
inside
Miura, M.
2003
MIOCROWAVE ASSISTED PYROLYSIS.
PROCESS PERFORMANCE HIGHLIGHTS:
• Totally closed system
• No air or oxygen added:
– minimum gas volumes generated – high calorific value on gases
• Low thermal masses give short start and shut down times of the reactor
• Precise temperature control:
- Low carry over of pollutants - Facilitates better product control
• Highly reducing atmosphere
• Electric input 5 – 25 % of feedstock energy content
• Small plants can be profitable
MIOCROWAVE ASSISTED PYROLYSIS PLANT USES:
• Conversion of biomass and bio wastes for bio fuels, energy, and bio chemicals
• Powerful tool in concentration of hazardous components in biomass and waste streams
• Waste reduction and materials recovery
• Attractive tool in education and international collaboration
• Development of new technology – industrialization
Microwave Assisted Pyrolysis
• Advantages:
– No need to grind the sample – Fast and uniform heating
– Enhanced overall efficiency
– Reduced undesirable localized burning or carbonization
– Low carry-over of contaminates – Cleaner biofuel products
– Better temperature control
Microwave Pyrolysis Reactor
Gases from Microwave Pyrolysis
Continuous Microwave Assisted Pyropysis Reactor at Norwegian University of Life Sciences
3 x1.5 kW generators
Screw reactor 2.5 m x 25 cm Ø Gas output to
distillation
Feedstock hopper
Waveguide
CONTIONOUS MIOCROWAVE ASSISTED PYROLYSIS PILOT SYSTEM PERFORMANCE
HIGHLIGHTS:
• Max microwave power input: 3 x 1.5 kW
• Design temperature: max 550 ºC
• Capacity: Up to 10 kg per hour
– Highly dependent on feedstock properties and water content
• Reactor chamber: 25 cm diameter / 2.5 m long
• Typical reaction time: 15 – 60 min
Microwave Pyrolysis
Microwave pyrolysis of corn stover at different input power.
0 500 1000 1500
0 10 20 30 40 50 60 70
Time (min)
Temperature (°C)
200w 300w 600w 900w
Micorwave Pyrolysis of Aspen
Canola Seed Press Cake
Municipal Solid Wastes
Microwave Pyrolysis
Yield of gas, liquid, and char from corn stover with 1 wt% of charcoal at 300-900W.
0 20 40 60 80 100
300 400 500 600 700 800 900
Input power (W)
Yield (%)
Gas Liquid Char
Microwave Pyrolysis of Manure
0 10 20 30 40 50 60
Composted Raw Manure Solids Fresh manure directly from barn
Per cent
Oil Char Gas
Yield of gas, liquid, and char from manure samples
Microwave Pyrolysis of Corncob and Cellulose
300W 1000W
Corncob Cellulose Corncob Cellulose
Gases (%) 14.36 7.52 46.88 23.64
Liquid (%) 16.34 13.76 30.16 43.64
Solids (%) 69.3 79.72 22.96 32.72
Pyrolytic Gas Composition
Micro-GC chromatograms of the microwave pyrolysis gas obtained from corncobs
Composition of Pyrolytic Gases
Retention time (min) Peak Name Percentage at 300w
Percentage at 600w Peak Info for Channel A (MS5A)
0.413 <H2> 6.33 17.68
0.659 <CO> 15.64 15.32
Peak Info for Channel B (PPQ)
0.365 <CO2> 39.68 32.58
0.382 <C2H4> 0.28 0.90
0.390 Acetylene 0.94 1.15
0.408 <CH4> 3.97 3.76
Micro-GC chromatograms of the microwave pyrolysis gas obtained from corn stover at 300W and 600W.
A: H2; B: CH4; C: CO2; and D: CO.
0 10 20 30 40 50
0 5 10 15 20 25
Time (min)
Yield (%)
300w 600w
A
0 10 20 30 40 50
0 5 10 15 20 25
Time (min)
Yield (%)
300w 600w
C
0 4 8 12 16
0 5 10 15 20 25
Time (min)
Yield (%)
300w 600w
B
0 2 4 6
0 5 10 15 20 25
Time (min)
Yield (%)
300w 600w
D
Pyrolytic Liquid Composition
GC-MS chromatograms of the pyrolytic liquid obtained from corncobs.
Composition of the Pyrolytic Liquid
• Hydrocarbons,
• Ketones,
• Aldehydes,
• Carboxylic acids,
• Esters,
• Nitrogenated compounds,
• Terpenes and steroids.
Physical and Chemical Properties of Bio-oil from Microwave Pyrolysis
• Analysis of
– moisture content – solid content
– pH
– ash content – heating value – elemental ratio – viscosity
– minerals
Physical and Chemical Properties of Bio-oil from Microwave Pyrolysis
• Stability of
– The raw bio-oil
– Blends of the bio-oil and methanol or ethanol or butanol
• Changes in viscosity and moisture content
as a function of storage temperature and
time.
Viscosity of bio-oils and bio-oils with solvent addition versus ageing period at room temperature
0 300 600 900 1200 1500
0 20 40 60
Aging time (d)
Viscosity (mPa · s)
Original 10% MeOH 10% EtOH
A
0 15 30 45 60
0 10 20 30 40 50 60
Aging time (d)
Viscosity (mPa · s)
20% MeOH 30% MeOH 20% EtOH 30% EtOH
B
Summary of the Physical and Chemical Properties of Bio-oils and Blends
• The ash and solid contents in the bio-oils were relatively low. The water content was around 15.2 wt %, solid
content 0.22 wt %, alkali metal content 12 ppm, dynamic viscosity 185 mPa ∙ s at 40°C. The gross high heating value was 17.5 MJ/kg for a typical bio-oil produced, about 50% of the petroleum oil.
• The aging tests showed that the viscosity and water
content increased and phase separation occurred during the storage at different temperatures. Adding methanol and/or ethanol to the bio-oils reduced the viscosity and slowed down the increase in viscosity and water content during the storage. Blending of methanol or ethanol with the bio-oils may be a simple and cost-effective approach to making the pyrolytic bio-oils into a stable gas turbine or home heating fuels.
Mass and Energy Balance for Microwave Pyrolysis
Bio-oil
~40-50 %
~15,200 BTU/kg Char residue
~20 %
~23,800 BTU/kg Corn stover
Microwave assisted pyrolysis
Need ~1,500BTU/kg Bio-Gas
~30-40 %
>10,000 BTU/kg
Continuous Microwave Assisted Pyropysis Reactor at Norwegian University of Life Sciences
3 x1.5 kW generators
Screw reactor 2.5 m x 25 cm Ø Gas output to
distillation
Feedstock hopper
Waveguide
Polyester + DGG
Composite Polyester + fibers
Composite Polyester film
Wood Adhesive
Sample Products
Polyurethane foam
Biofuels
Research at CFB
Industry Involved
• Bixby Energy Systems from US
• Xwaste International from Norway
Closing Remarks
• Results from our research demonstrated great potential of hydrothermal treatment and microwave assisted pyrolysis for
making biofuels from biomass
• Further study to optimize the processes, develop and improve continuous pilot
scale systems, reaction kinetics
modeling, and test on different catalysts
and feedstocks are necessary
Questions?
R. Roger Ruan, Ph.D., Yangtz Scholar Distinguished Guest Professor, Nanchang University, and Professor, Department of Bioproducts and Biosystems Engineering
Director, Center for Biorefining
Co-Leader and Coordinator, IREE Bioenergy & Bioproducts Cluster University of Minnesota
1390 Eckles Avenue, St. Paul, MN 55108, USA (612) 625-1710, (612) 624-3005 (fax)
Email: [email protected]
http://biorefining.cfans.umn.edu