Broch Amber

8/12/2019 Broch Amber

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Amber Broch, S. Kent Hoekman, Curt Robbins DesertResearch Institute

Chuck Coronella Univ. of Nevada, Reno

Larry Felix, Wei Yan Gas Technology Institute

Pacific West Biomass Conference

January 16-18, 2012

San Francisco, CA

Renewable Solid Fuels via HydrothermalCarbonization HTC) of Cellulosic Biomass
http://www.unr.edu/ur/images/logo280.jpg


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Background and Introduction Lignocellulosic biomass is a promising feedstock for

production of heat, chemicals, fuels, and electrical power

Diverse biomass sources:o Woods, agricultural wastes, grasses, other

Large diversity of biomass sizes, shapes, compositions, and

other parameters creates difficulty in:o Handling, transporting, and storing different materials

o Feeding different materials into a single thermal conversionunit

2


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Purpose of Biomass Pre-Treatment

Three main objectives1. Homogenize feedstocks

o Reduce handling difficulties

o Convert multiple materials into a single feedstock

2. Increase energy densityo Reduce the oxygen content of raw biomass

o Higher energy density reduces transportation andhandling costs

3. Improve storage stability logisticso Address seasonality of some feedstocks

o Improve suitability for co-firing with coal

Overall goal:

Convert biomass into a solid biochar that resembles low-grade coal3


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Biomass Thermal Pre-Treatment

Processes

Two processes are of particular interest

1. Torrefaction

Mild form of pyrolysis

Dry conditions, low O2 levels

Produces gases and solid char

2. Hydrothermal Carbonization (HTC)

Also known as wet torrefaction,

hydrothermal pretreament (HTP), hot

pressurized water (HPW) treatment, and

others.

Produces gases, liquids, and solid char

Pressure

Vessel

155-295oC

Solid

Biomass

H2O

Recovered

Solid

(Bio-char)

Condensed

Liquid

Non-

condensable

gases

To gasifier/ pyrolyzer

For energy/ fuels

HTC Process

4


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HTC Laboratory Set-Up 2-Liter Stirred Parr Pressure Vessel

Parr

Reactor

Motor

Ice Bath

He

Tedlar

Bag

Dilute

Gases

Mass Flow

Meter

Mass Flow

Controller

T

T

P

T

Relative Humidity

Instrument

1. Biomass & H2O

are heated to

temperature and

held for set time

2. Bomb is cooled

in an ice bath

3. Gases are collected in a Tedlar bag by

sparging Helium through the reactor

E-11

Solid

Liquid

4. Reactor is opened and

contents are weighed,

rinsed and separated

by vacuum filtration

He (purging & diluting)

Heated Pretreated gas

Products

Gases Liquids HTC Char

5


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HTC Feedstocks and Lab Processes

Treatment of Different Feedstocks:o Woody Feedstocks:

Loblolly Pine

Tahoe Mix (White Fir/ Jeffery Pine)

Pinyon/ Juniper

o Herbaceous Feedstocks: Rice Hulls

Corn Stover

Sugar Cane Bagasse

Process Conditions:

o Temperature: 155-295C

o Hold Time at Temperature: 5 - 60 min

o Water/ Biomass Ratio: 4 - 15

o Feedstock Size: ~ in.

Raw Loblolly

255 C for 30

min

215C for 30

min

175 C for 30

min

6


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Laboratory Analyses of Products

MeasurementsGases

Volume (flow

measurements)

Composition - GC

Liquids

Total Organic Carbon

Organic Acids (IC)

Carbohydrates (HPLC)

Non-volatile mass

pH

Solids and Feedstocks C,H,N,S,O

Energy Content(calorimetry)

Moisture Content Acetone Extractables

Volatiles, Fixed Carbon,Ash

Mass Balance

Carbon Balance

Energy Densification

Pelletization Characteristics

7

Determination


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Method Development

GC Method for Gaseous Products

8

2 column method provides identification of H2, CO, CO2,CH4, Ethane, Ethene, Acetylene, Propene.

The dominant gaseous product is CO2, with a small amount

and CO. Typically, no other identified species are measured

GC Conditions:Column 1:

6-ft. x 1/8 in. Molecular Sieve 13X

90C isothermal

Column 2:

6-ft. x 1/8 in. Silica Gel 40 C isothermal for 9 min.; then

increase 15C/min to 200C (5-min.

hold)

Sample loop: 1.0 mL

Carrier gas: He (11.0 mL/min.)

Detector: TCD 105 15 20

H2

COCH4

Ethane

CO2

Ethene

Acetylene

Propene

O2

N2

CO

CO2

HTC of Loblolly Pine @ 255

Calibration Gas Mixture

Retention Time, min.

0


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Method Development-

HPLC Method for Water Soluble Products

9

Developed to quantify 5-HMF and Furfural in liquids

Simultaneous detection with other sugars

Suc

rose-Trehalose

Glucose-Pinitol

G

alactose,Xylose,Mannose

Fr

uctose,Inositol,Arabinose

Le

voglucosan F

urfural

Erythritol

Mann

itol,Glycerol

Arabitol

HPLC Chromatogram of HTC Liquid from Loblolly Pine at 255C.

HPLC Conditions: Waters Alliance 2695 with

Waters 2414 Refractive Index

(RI) detector

Waters Sugar-Pak TM column

(6.5 x 300 mm)

Isocratic elution with water at

0.4 mL/min Column temp: 60C

Detector temp: 50C

Other methods described in

Hoekman, S.K., A. Broch, and C. Robbins, 2011: Hydrothermal Carbonization (HTC) of

Lignocellulosic Biomass. Energy Fuels, 25 (4), pp 18021810


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Effect of Temperature on Mass Recovery

10

Percentageofstartingdryfeedstock

Tahoe Mix Loblolly Pine Pinyon/ Juiper

Corn Stover Rice Hulls Sugar Cane Bagasse

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

'215* 235 255 275

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

215 235 255 275

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

215 235 255 275

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

215 235 255 275

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

215 235 255 275

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

215 235 255 275

Set Temperature of Reaction

Solid CharH2O Solubles(non-volatiles, acetic and

formic acids, 5-HMF and

furfural)

Gases

Balance is primarily water


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Effect of Temperature on Energy

Content of HTC-Char

11

Energy content of HTC char increases above temperatures around 200C

Feedstock

Replicate experiments


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Effect of Temperature on Atomic O/C

Ratio of HTC Char

12HTC treatment of both woods and grasses results in similar Atomic O/C ratios above temperatures

around 250 C


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Effect of Temperature on Sugar Recovery

13

Maximum sugar recovery in the liquids occurs around 215-235C

Sugar composition changes after ~200C

Percentageofstartin

gdryfeedstock


Percentageofstart

ingdryfeedstock

Tahoe Mix Loblolly Pinyon/ Juniper

Corn Stover Rice Hulls Sugarcane Bagasse

0%

1%

2%

3%

4%

5%

6%

7%

8%

9%

175 215 235 255 275

0%

1%

2%

3%

4%

5%

6%

7%

8%

9%

175 215 235 255 275

0%

1%

2%

3%

4%

5%

6%

7%

8%

9%

175 215 235 255 275

0%

1%

2%

3%

4%

5%

6%

7%

8%

9%

175 215 235 255 275

0%

1%

2%

3%

4%

5%

6%

7%

8%

9%

175 215 235 255 275

0%

1%

2%

3%

4%

5%

6%

7%

8%

9%

175 215 235 255 275


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Effect of Temperature on Organic Acids

14

Percentageofstart

ingdryfeedstock


Tahoe Mix Loblolly Pinyon/ Juniper

Corn Stover Rice Hulls Sugarcane Bagasse

0%

2%

4%

6%

8%

10%

12%

215 235 255 2750%

2%

4%

6%

8%

10%

12%

215 235 255 2750%

2%

4%

6%

8%

10%

12%

215 235 255 275

0%

2%

4%

6%

8%

10%

12%

215 235 255 275

0%

2%

4%

6%

8%

10%

12%

215 235 255 275

0%

2%

4%

6%

8%

10%

12%

215 235 255 275

Recovery of organic acids in the liquid increases with increasing reaction temperature


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Pelletization of HTC Char

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Pelletization helps improve storage,transportation and handling of biomassfeedstocks.

Compare pelletization behavior of rawbiomass, torrefied biomass and HTC Char

Pellet Production:o 15 MT hydraulic press with heated die (set

at 7.5 MT and 140C)

o 13 mm diameter with L/D ratio of 0.6 to0.75.

o 30 second hold time

Pellet Characterization Testso Fuel value

o Abrasion

o Hydrophobicity


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Pellet Behavior Comparison

Pellet Density Hydrophobicity

16

Mass and energy density of

HTC-char pellets increase with

increasing treatment

temperature. HTC-Char has higher mass and

energy density than raw

feedstock or torrefied char.

Pellets are immersed in water.

Raw feedstock pellet begins todisintegrate immediately.

Torrefied pellet crumbles afterremoval from water

HTC-Char pellet maintainsintegrity for weeks.

Raw Feedstock HTC Char Torrefied

Time: 0 min (no water)

Time: 1 min in water

Time: 2 hrs, removed from water


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Conclusion

17

HTC process is an effective way to increase the value of biomassfeedstocks

o Energy density of many feedstocks increased by ~ 40%

o Can be applied to wide variety of biomass types

Two-Step pre-treatment process could be of greater value:

o Low temp (~200oC) for maximum sugar recovery

o High temp (~250-275oC) for maximum biochar energy

Pelletization further enhances the value of HTC-char

o Easily forms stable pellets having very high energy density

Ancillary benefits being investigated:

o Co-firing with coal looks attractive

o Use of biochar for soils improvement and carbon sequestration

o Possible uses of water-soluble products


18/18

Acknowledgements

18

o DOE funding sources DE-FG36-01GO11082

EE-0000272

o Keri Noack- Laboratory Work

o Stephanie Salke, Anna Cunningham- Laboratory Analyses

o Hoekman, S.K., Broch, A., Robbins, C., 2011. Hydrothermal Carbonization (HTC) of

Lignocellulosic Biomass. Energy & Fuels 25, 1802-1810.

o Acharjee, T.C., Coronella, C.J., Vsquez, V.R., 2011. Effect of Thermal Pretreatment on

Equilibrium Moisture Content of Lignocellulosic Biomass. Bioresource Technology102,

4849-4854.

o Yan, W., Hastings, J.T., Acharjee, T.C., Coronella, C.J., Vsquez, V.R., 2010. Mass and

Energy Balances of Wet Torrefaction of Lignocellulosic Biomass. Energy & Fuels 24, 4738-

4742.

o Yan, W., Acharjee, T.C., Coronella, C.J., Vsquez, V.R., 2009. Thermal Pretreatment of

Lignocellulosic Biomass. Environmental Progress & Sustainable Energy28 (3), 435-440.

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