11

Potential of Eichhornia Crassipes for Biomass Refining

Jessica E. Hronich, Lealon Martin, Joel Plawsky, & Henry Bungay

November 7th, 2007

AIChE Conference 2007

22

Introduction

• Department of Energy goal:• 60 Bgal/yr ethanol by 20301

• Current production• 5.4 Bgal/yr blended into gasoline for 20062

• 129 Ethanol plants, and growing

• The need for diverse feedstocks• Corn grain can only meet 15% of transportation

needs1

• Cellulosic ethanol can fill remainder• Greater energy output/input ratio31U.S. DOE. 2006. Breaking the Biological Barriers to Cellulosic Ethanol: A Joint Research Agenda, DOE/SC-0095, U.S.

Department of Energy Office of Science and Office of Energy Efficiency and Renewable Energy (www.doegenomestolife.org/biofuels/).2 “Biofuels in the U.S. Transportation Sector” Energy Information Association, Oct. 15, 2007. (http://www.eia.doe.gov/oiaf/analysispaper/biomass.html#1)3 Bourne, J.K. “Green Dreams” National Geographic, 2007. (http://magma.nationalgeographic.com/ngm/2007-10/biofuels/biofuels-interactive.html)

33

Feedstock Evaluation

• Ideal Attributes• Wide availability• Ease of cultivation• Frequent harvest

cycles• No / low competition

with food crops• Easy to process• Inexpensive

• Water hyacinth• Global invasive

nuisance weed• Growth can exceed

200 tons DM / ha / yr• 2 week harvest cycle• Aquatic plant• Low-tech processing• Millions of dollars

spent each year to remove / dispose

44

Process Description

• Cultivation• Harvest &

Collection• Pressing• Pretreatm

ent / Storage

• Hydrolysis / Fermentation

55

Cultivation

• Infested waterways• Removal credit• Developing countries

• Hyacinth cultivation (farms)• Unused commercial

ponds / lakes

66

Harvest & Collection

77

Harvest & Collection

• Novel cutter design• Simply slice mats

• Mat width design variable

• Length dependent on connectivity

• Use less energy than traditional harvesters

• Tow swaths of mats to shore

• Cut pattern to allow re-growth

Factory

88

Pressing

• Can remove approximately 97 wt% of the water

• Will decrease volume for silage

• Water will be processed (if necessary) and returned to lake

99

Pretreatment / Storage

• Partial Anaerobic digestion• Approximately

14 days• Less energy

intensive

• Remove loose water

• Combine with storage to reduce costs

1010

Process Cost Estimation• Estimation allowed for multiple inputs to affect

overall cost per ton to produce• Referenced current

biomass-to-ethanol evaluations

• Manufacturing cost estimation for chemical process industry adapted for agribusiness plan1

• Key design parameters taken from literature, manufacturers, and best guesses

1Ulrich D, Vasudevan T, (2004) Chemical Engineering Process Design and Economics: A Practical Guide. Ulrich Publishing, 409-435

1111

Key Design Parameters

• Cultivation• Lake covered in 300

acres hyacinth• Located in United States• 100 ton dry matter / ha /

yr

• Harvest / Collection• Cut width of 3.5 m• Cut speed of 45 m / min• Harvested 8 hours / day

• Pressing• 97 wt% water removal• Power usage: 18HP/ton

fiber/hr

• Pretreatment / Storage• 14 days to digest

• Misc.• Labor ($10 / hr +

benefits)• Overheads• Taxes, insurance• Depreciation

1212

Cost Estimation

Depreciation ($1.07)

Labor ($10.64)

Utilities ($6.01)

Maintenance ($1.74)

Overheads ($5.21)

Taxes & insurance ($2.95)

Total Cost: $28 / ton of Total Cost: $28 / ton of dry matterdry matter

1313

Sensitivity Analysis

• Lowest possible cost• 1 harvester & 1

transport boat• Cut width

greater than 7m• Cut speed

greater than 45 m/min

• Operation most likely at 3.5 m and 45 m/min

Bio

mass

Cost

($

/dry

to

n)

Cut Speed (m/min) Cut W

idth

(m)

1414

Future Work

• Investigation of digestion process• Temperature• pH• Residence time

• Hydrolysis methods• Acid• Enzymatic

• Fermentation yields• Quality of biomass produced

• Application to other aquatic nuisance weeds

Photo courtesy of Willey Durden, USDA Agricultural Research Service, www.forestryimages.org; Image Number 0002100.

1515

Summary

• Water hyacinth as a feedstock• Rapid growth rate• Wide availability• Low cost

• Exportable low-technology process• Cost Estimation / Sensitivity Analysis• E. Crassipes is an economically viable biomass

feedstock• A blight on an ecosystem can be used as an economic

benefit • Cost competitive with other feedstocks (less than $40

per dry ton)

1616

Acknowledgements

• NSF IGERT fellowship• Rensselaer Chemical & Biological

Engineering• The Martin Group