Petter H. Heyerdahl, Associate Professor Department of Mathematical Sciences and Technology

Norwegian University of Life Sciences (UMB) and

R. Roger Ruan, Professor and DirectorCenter 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 PyrolysisPyrolysis of Biomassof Biomass

For BioFor Bio--fuel Production fuel Production –– Progress ReportProgress 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 ProcessingFacility (OMPF) Products

Densified ChemicalFeedstock (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-dieselOil

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-crudeOil-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 (%)

Yie

ld (%

)

Gas phase Liquid phase

Residues Total

Temperature (°C) Init N2 Press. %Collected %Char %Oil280 0 90.1 44.8 16.6300 0 90.9 40.3 20.6320 0 90.8 43.l9 13.7340 0 90.5 37 22.3

Temperature (°C) Init N2 Press. %Collected %Char %Oil280 500 92.6 40.3 26.0300 500 93.3 35.4 30.0320 500 91.3 32.2 40.0340 500 92.1 29.4 46.1350 500 93.7 33.2 31.7360 500 92.0 25.4 42.8365 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

LiquidsMicrowave

energy input

Vola- tiles

Char/Carbonand other inert solid material

Cond

ense

r

Heating Methods

Lowtemperature

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

Hightemperature

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 70Time (min)

Tem

pera

ture

(°C

)200w300w600w900w

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)

Yie

ld (%

)Gas

Liquid

Char

Microwave Pyrolysis of Manure

0

10

20

30

40

50

60

Composted Raw Manure Solids Fresh manuredirectly from barn

Per c

ent

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 17.680.659 <CO> 15.64 15.32

Peak Info for Channel B (PPQ)0.365 <CO2> 39.68 32.58

0.382 <C2H4> 0.28 0.900.390 Acetylene 0.94 1.150.408 <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.

01020304050

0 5 10 15 20 25

Time (min)

Yie

ld (%

)

300w 600w

A

01020304050

0 5 10 15 20 25

Time (min)

Yie

ld (%

)

300w 600w

C

0

4

8

12

16

0 5 10 15 20 25

Time (min)

Yie

ld (%

)

300w 600w

B

0

2

4

6

0 5 10 15 20 25

Time (min)Y

ield

(%)

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 60Aging time (d)

Visc

osity

(mPa

· s)

Original10% MeOH10% EtOH

A

0

15

30

45

60

0 10 20 30 40 50 60

Aging time (d)

Visc

osity

(mPa

· s)

20% MeOH30% MeOH20% EtOH30% 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/kgBio-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 + DGGComposite Polyester + fibers

CompositePolyester 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 Bioproductsand 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: ruanx001@umn.eduhttp://biorefining.cfans.umn.edu