using biomass at ethanol plants for combined heat and ...condensing turbine • biomass integrated...

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Using Biomass at Ethanol Plants for Combined Heat and Power (CHP)Combined Heat and Power (CHP)

Vance [email protected]

ProfessorBi d t d Bi t E i i

www.biomassCHPethanol.umn.edu

Bioproducts and Biosystems Engineering

Using Corn Stover for Energy at Ethanol Plants

July 11, 2011

Project Support

Xcel Energy Renewable Development Fund

University of MinnesotaInitiative for Renewable Energy and the Environment

Project Cooperators


AMEC E&C Services Inc.LLS Resources, LLC

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Biomass for Electricity and Process Heat at Ethanol Plants



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Motivations for Using Biomass

• Reduce fossil energy inputs i e improve• Reduce fossil energy inputs, i.e. improve energy balance

• Reduce natural gas costs

• Decrease net greenhouse gas emissions

• Generate renewable dependable (base


• Generate renewable, dependable (base load) power that complements power from renewable sources that are variable such as wind and solar

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Conventional Dry-grind Ethanol Process



Energy Ratio: 1.7

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Energy Ratio: 1.7

Combined Heat and Power (CHP) Concept

• Simultaneous production of two or more types of usable f i l ( l ll denergy from a single energy source (also called

“Cogeneration”)• Use of waste heat from power generation equipment


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Biomass Technology Options

• Process heat for the ethanol plant• Combined heat and power (CHP) – process

heat plus generate electricity with a back pressure turbine

• CHP plus grid – process heat plus generate electricity with an extraction turbine and condensing turbine


condensing turbine• Biomass integrated gasification combined cycle

(BIGCC) – process heat plus generate electricity with gas turbine and steam turbine.

Biomass Fuel Properties

TypeHeating val.(dry),

Ash

%

Nitrogen

%

Sulfur

%

Chlorine

%yp ( y)

Btu/lb % % % %

DDGS 9350 4 4.8 0.8 0.2 - 0.3

Syrup* 8500 7 2.6 1.0 0.35

Corn stover 7700 6 - 8 0.7 0.04 0.1 - 0.2


Corn cobs 7900 1.5 0.4 0.04 0.1 - 0.2

Wood8400 -8900

0.5 - 1.5 <0.2 0.02 0.05

*Syrup moisture 67%; other fuels 10 - 15%

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Fluidized Bed Combustion

Li b d• Limestone bed material for reducing emissions

• Flexible for


www.tekes.fi/opet/chp.htm

different types of fuels

Rentech-SilvaGas Process

• Steam blown gasifier Steam blown gasifier, atmospheric pressure• Medium energy value synthesis gas• Char combusted in comb stor


combustor• Gasifier heated by hot sand from combustor

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Emissions Control• Dryer volatile organic compounds (VOC)

• Route dryer exhaust air through combustor• Route dryer exhaust air through combustor

• Particulate matter• Cyclones• Baghouse

• Sulfur and chlorine emissions• Limestone sorbent bed material


• Limestone sorbent bed material• Flue gas semi-dry scrubbing

• NOx emissions• Selective non-catalytic reduction (SNCR)

ASPEN Plus Modeling• Started with USDA model of a dry-grind fuel

ethanol plantethanol plant• Used this model to understand the ethanol

process and its energy requirements• Added components to the model

– Biomass conversion (fluidized bed combustion or gasification)


– Electricity generation– Emissions control (NOx, SOx, Chlorine)– Modified drying system to use process steam (steam

tube dryer)

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Conventional Dry-grind Ethanol Process


Steam Tube DryersUsed for drying co-products and biomass fuel


Davenport Dryer Co. http://bcgcommunications.com/

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Electricity Generation – Steam Turbine

• Back-pressure Turbine• Constant steam pressure at outlet• Should use all outlet steam for process needs

• Extraction Turbine• Extract steam at constant pressure for process


• Condense excess steam at low pressure

Electricity Generation – Combined Cycle


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Corn Stover Combustion – CHP


Corn Stover Combustion: CHP + Grid


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Syrup and Corn Stover Combustion: CHP


Integrated Gasification Combined Cycle


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System Comparisons

• CHP, CHP + Grid, and BIGCC with corn stover and syrup and corn stover as biomass fuels

• Life-cycle GHG analysis for fuel ethanol based on Liska et al. (2009), Plevin (2009), and GREET (2009)


( ) ( )• Life-cycle GHG analysis excludes indirect

land use change effects

Power and Efficiency*

SystemFuelInput

PowerTotal (Grid)

Power Gen. System

Therm EffSystem Input MWth

Total (Grid), MWe

Eff. %Therm. Eff.,

%

CHP Syrup & Corn Stover

75 8.8 (2.8) 11.8 64.5

CHP Corn Stover

78 10.9 (4.6) 14.0 77.0

CHP+G Syrup


CHP+G Syrup & Corn Stover

104 16.0 (9.6) 15.4 53.0

CHP+G Corn Stover

104 17.4 (10.7) 16.7 63.6

*50 million gallon/yr plant

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Power and Efficiency*

SystemFuelInput MWth

PowerTotal (Grid),

MWe

Power Gen. Eff. %

System Therm. Eff.,

%

BIGCC Syrup & Corn Stover

110 33.6 (24.7) 30.6 73.3

BIGCC Corn Stover

110 33.7 (24.6) 30.6 72.6


Stover

NGCC 110 35.2 (30.3) 32.0 77.7

*50 million gallon/yr plant

Conventional Ethanol Plant

80

100 Gasoline

Ethanol Net

0

20

40

60

g C

O2e/

MJ Coproduct Credit

Biorefinery Other

Denaturant 2% Vol.Fossil Electricity

Natural Gas


U.S. Midwest average corn ethanol (Liska et al., 2009; Plevin, 2009)

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Input Output Net GasolineCorn Production

Conventional Plant Gasoline

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CHP and BIGCC Stover

60

80

100Gasoline

Ethanol Net

40

-20

0

20

40

60

g C

O2e

/MJ

Renewable Elec. Credit

Coproduct Credit

Stover Fuel

Biorefinery Other


-80

-60

-40

Input Output Net Input Output Net Gasoline

Denaturant 2% Vol.

Corn Production

CHP BIGCC Gasoline

116.5%124.1%

%

120%

140%

)

CHP, CHP+G, and BIGCC vs GHG Reduction

38.9%

66.3%

79.1% 80.4%

91.8%

20%

40%

60%

80%

100%

GHG Reduction (%)


0%

20%

Natural Gas Plant (Liska)

CHP Syrup & Stover

CHP Corn Stover

CHP+G Syrup & Stover

CHP+G Corn Stover

BIGCC Syrup & Stover

BIGCC Corn Stover

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116 5%124.1%120%

140%)

BIGCC & NGCC vs GHG Reduction

38.9%

116.5%

93.4%

40%

60%

80%

100%

GH

G R

edu

ctio

n (

%)


0%

20%

Natural Gas Plant (Liska)

BIGCC Syrup & Stover

BIGCC Corn Stover

NGCC Natural Gas

Electric Power Production Potential in Minnesota

A i t l 1 billi ll f l• Approximately 1 billion gallons of annual corn ethanol production capacity

• 500 MW could be produced and sent to grid if biomass power generation were fully implemented at these plants

( )


• Renewable, dependable (base load) power that complements power from renewable sources that are variable such as wind and solar

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Estimated Capital Costs*System 50 Mil gal/yr 100 Mil gal/yr

Ethanol Plant – Conv. NG $75,000,000 $121,850,000

CHP Syrup & Corn Stover $131,800,000 $214,100,000

CHP Corn Stover $144,000,000 $233,900,000

CHP+G Syrup & Corn Stover

$146,650,000 $238,200,000

CHP+G Corn Stover $162,000,000 $263,200,000


BIGCC Syrup & Corn Stover

$207,400,000 $336,900,000

BIGCC Corn Stover $206,700,000 $335,800,000

NGCC Natural Gas $145,000,000 $235,550,000

*Estimated by AMEC E&C Services Inc.

ReferencesDe Kam, M.J., R.V. Morey, and D.G. Tiffany. 2009. Integrating biomass to produce heat and power at ethanol plants. Applied Engineering in Agriculture 25(2): 227-244.De Kam, M.J., R.V. Morey, and D.G. Tiffany. 2009. Biomass integrated gasification combined cycle for heat and power at ethanol plants. Energy Conservation and Management 50: 1682-1690.EPA. 2007. Impact of Combined Heat and Power on Energy Use and Carbon Emissions in the Dry Mill Ethanol Process. Washington D.C.: Environmental Protection Agency. Available at: http://www.epa.gov/chp/markets/ethanol.html. Accessed 14 December 2009.Kwiatoski, J.R., A.J. McAloon, F. Taylor, and D.B. Johnston. 2006. Modeling the process and costs of fuel ethanol production by the corn dry-grind process Industrial Crops and Products 23:288-296corn dry grind process. Industrial Crops and Products 23:288 296.Gielen, D. 2003. CO2 removal in the iron and steel industry. Energy Conversion and Management 44 (7): 1027-1037.GREET. 2009. The Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) Model. Ver. GREET 1.8c.0. Argonne, IL: Center for Transportation Research, Energy Systems Division, Argonne National Laboratory. Available at: http://www.transportation.anl.gov/modeling_simulation/GREET/index.html. Accessed 7 July 2009.Guinn, J.H. 1980. Method for injecting carbon dioxide into a well. United States Patent No. 4,212,354. Dated 15 July 1980.Kaliyan, N., R.V. Morey, and D.G. Tiffany. 2011. Reducing life cycle greenhouse gas emissions of corn ethanol by integrating biomass to produce heat and power at ethanol plants. Biomass and Bioenergy 35(3): 1103-1113.Kheshgi, H.S., and R.C. Prince. 2005. Sequestration of fermentation CO2 from ethanol production. Energy 30(10): 1865-1871.Liska, A.J., and K.G. Cassman. 2009. Response to Plevin: implications for life cycle emissions regulations. Journal of Industrial Ecology 13(4): 508-513.Liska, A.J., H.S. Yang, V.R. Bremer, T.J. Klopfenstein, D.T. Walters, G.E. Erickson, and K.G. Cassman. 2009. Improvements in life cycle energy efficiency and greenhouse gas emissions of corn-ethanol. Journal of Industrial Ecology 13(1): 58-74.


McAloon, A.J., F. Taylor, and W.C. Yee. 2004. A model of the production of ethanol by the dry grind process. Proceedings of the Corn Utilization & Technology Conference, Indianapolis, IN., June 7-9. Poster 58.Morey, R.V., D.L. Hatfield, R. Sears, D. Haak, D.G. Tiffany, and N. Kaliyan. 2009. Fuel properties of biomass feed streams at ethanol plants. Applied Engineering in Agriculture 25(1): 57-64.Morey, R. V., N. Kaliyan, D. G. Tiffany, and D. R. Schmidt. 2010. A corn stover supply logistics system. Applied Engineering in Agriculture 26(3): 455-461.Plevin, R.J. 2009. Modeling corn ethanol and climate: a critical comparison of the BESS and GREET models. Journal of Industrial Ecology 13(4): 495-507.Tiffany, D.G., R.V. Morey, and M.J. De Kam. 2009. Economics of biomass gasification/combustion at fuel ethanol plants. Applied Engineering in Agriculture 25(3): 391-400.USDA. 2007. ASPEN Plus Model for Shelled Corn to Ethanol Process Analysis – Dry Grind Starch Fermentation. USDA ARS.

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Questions?

Vance [email protected]


using biomass at ethanol plants for combined heat and ...condensing turbine • biomass integrated...

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