Biogas: A New Paradigm in Ethanol Production

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Biogas A New Paradigm in Ethanol Production
Presented by Brian Barber, E3 BioFuels Project
Development Manager, March 28, 2007.
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The Closed-Loop System

• Anaerobic digestion units (ADUs) transform manure
  and thin stillage, a byproduct of ethanol
  production, into biogas post-digestion wastes
  are subjected to further treatment.
• An ethanol refinery operates on biogas produced
  from the anaerobic digesters.
• An onsite dairy/feedlot uses the byproduct of
  ethanol production, wet distillers grain, as a
  primary portion of the feed for cattle thus
  completing the loop.
• In unison, the closed-loop may serve as the most
  energy-efficient ethanol producer in the world.

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The Closed-Loop System
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The Mead Feedlot
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The Mead Feedlot

• Built in the late 1960s and located in Mead,
  Nebraska.
• 30,000-head capacity, average occupancy near
  28,000.
• Entire feedlot 9 half-mile confinement buildings
  with pens that each shelter 70 to 100 cattle.
• Beef cattle have been fed distillers grains for
  years in recent months, cattle have been fed wet
  grains.
• Unique, concrete slatted flooring at the feedlot
  ensures that manure does not mix with dirt and
  sand, which can hinder anaerobic digestion.

Top Wet distillers grain in storage . Left A
feed mix of distillers grain, flaked corn, hay,
and silage.
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The Mead Feedlot Slatted Floor

• At Mead, wastes fall into a unique slatted
  floor, and are then piped to a manure lagoon.
• Wastes from the lagoon are then brought to and
  processed in anaerobic digestion units.
• The slatted floor is unique, but new projects,
  retrofits and numerous flush-disposal dairies can
  incorporate closed-loop technology.

Top The slatted floor at the Mead feedlot.

Below Example of a dairy
flush-disposal system.
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Anaerobic Digestion Technology

• Two, 4-million-gallon digesters at the Genesis
  plant in Mead process manure and thin stillage.
• Various bacteria, or bugs, decompose the mixed
  wastes and biogas is captured for ethanol
  production.
• The stillage and wastes are mixed in an influent
  tank a flare burns excess biogas, which also
  could be converted into electricity.

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ADU Slurry Facts and Figures

• Daily capacity 250,000 gallons of thin
  stillage 150,000 gallons of manure/wastes.
• E3 BioFuels Mead facility the Genesis plant
  - is only one in the country to digest large
  volumes of thin stillage.

• Thin stillage initially is 160
  degrees (F), and then cooled
  slightly so that slurry achieves optimum
  temperature of 100 degrees.
• E3 BioFuels closed-loop process increases
  efficiency Digester benefits from latent heat of
  stillage, whereas stand-alone digester would use
  biogas to maintain optimum temperature ... 20-25
  percent of biogas is saved because we use latent
  heat.

Above photo Cooling tower (left) and ADU
(right).
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Biogas Burn Baby, Burn!

• Biogas During testing, comprised 65 percent
  methane, 35 percent carbon dioxide 70-30 percent
  mix expected when closed-loop is fully
  operational.
• Heating value of a unit of biogas 70 percent of
  unit of fossil-fuel natural gas also, biogas
  moisture content is slightly greater than that of
  natural gas.
• At full-scale production, 2 million cubic feet of
  biogas would be burned each day.
• E3 BioFuels expects that biogas will replace
  90-100 percent of natural gas requirements,
  drastically increasing the net-energy balance of
  ethanol production.

Pictured is a tower of the ethanol refinery, the
sole end-user of biogas produced at Mead.
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Biogas Plan B

• Natural gas or diesel can be used as a back-up
  fuel for ethanol production.
• Additional lagoons have been built
• A) A lined 110-million-gallon storage lagoon for
  the recycling of closed-loop process water,
  helping to minimize use of local water supply.
• B) An overflow lagoon so that contents of
  digester can be safely evacuated, if needed.

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Avoided Costs of Natural Gas

• Vast majority of ethanol refineries are fueled by
  natural gas natural gas comprises up to 30
  percent of an ethanol refinerys operational
  costs.
• In 2005 dollars, the federal Energy Information
  Administration (EIA) predicts Henry Hub
  natural-gas spot prices at 6.28 per million BTU
  in 2010, 5.71 per million BTU in 2020, and 6.52
  per million BTU in 20301. Local gas prices for
  end-use industrial consumers will be higher.
• Bottom line Natural gas is unlikely ever again
  to be cheap. Meanwhile, an abundance of
  homegrown biogas remains largely untapped. This
  biogas can serve as a direct and more
  cost-effective substitute to natural gas, and is
  devoid of market fluctuations and potentially
  limited supply due to political instability.
• 1 The federal Energy Information
  Administration (EIA), a branch of the federal
  Department of Energy. Annual Energy Outlook
  2007, page 199. Reference case for this analysis.

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Biogas Other Financial Benefits

• Greenhouse gas credits Methane is 18 to 23 times
  more potent a greenhouse gas than carbon even
  with voluntary Chicago Climate Exchange (an
  offset for one ton of carbon dioxide costs about
  4), savings can be significant.
• Biogas has more value as natural gas substitute
  than as a fuel for electricity Especially in the
  Midwest, electrical utility rates can be cheap
  (.04/kilowatt hour) biogas value is retained
  when it replaces natural gas especially when
  serving one end-user. Also, burning biogas for
  boilers is substantially more energy-efficient
  than converting it into electricity.
• Numerous state and federal financial incentives
  are offered for waste-disposal technologies
  (ADUs) such as those used at Mead.

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Water Pollution Solvency

• Use of closed-loop technology not only provides
  cost-effective biogas, it also solves animal
  wastes, the leading contributor to agricultural
  run-off, the No. 1 contributor to water pollution
  in the United States.1
• The Mead feedlot stores and disposes of animal
  wastes in similar fashion to other federally
  defined Confined Animal Feeding Operations, or
  CAFOs.
• Without closed-loop technology at Mead (including
  anaerobic digesters and a nutrient-recovery
  unit), the waste equivalent of a city of 350,000
  would be WITHOUT A TREATMENT FACILITY!
• 1 U.S. Environmental Protection Agency Office of
  Compliance. Prepared statement, May 13, 1998.

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Wastes After Digestion

• Anaerobic digestion reduces volume of wastes by
  40 to 50 percent and solves greenhouse gas
  emissions but then what?
• Wastes are then processed in a nutrient-recovery
  unit that extracts valued commodities such as
  aqueous ammonia, potassium and phosphorus.
• Remaining waste materials can either be
  composted, directly applied to fields, or used as
  livestock bedding.

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Beyond Mead

• Concentrated Animal Feeding Operations (CAFOs)
  Federally defined as 700 dairy cattle or 1,000
  feeder cattle.
• Federal, state, local mandates may force better
  environmental stewardship and regulatory
  compliance at CAFOs, presenting opportunities for
  E3 BioFuels.
• 25 million gallon per year ethanol plant would
  require 30,000 beef cattle or 16,000 dairy cattle
  an estimated 2,700 feedlot and dairy CAFOs are
  large enough to help form a closed-loop system.
• E3 BioFuels is leading the industry With
  operational facility in Mead, we are at least two
  years ahead of other potential closed-loop
  competitors.

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Appendix A The Closed Loop
Red Traditional Cost Avoided by E3 Bio
Fuels Green Income Sources
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Appendix B Waste Management Tech
Water
Enzymes
Enzymes
Carbon Dioxide
Aqueous Suspended Solids
Corn Solids
Unconverted Solids
Beer Solids
Wet Cake Solids
Corn Mash
Cooked Mash
Mash Preparation
Sugar Synthesis
Cooker Liquefier
Fermenter
Beer Separator
Stillage Centrifuge
Ammonia
Sugar Solution
Stillage
Lime
CW
CW
Steam
Steam
Steam
Suspended Solids (Thin Stillage)
Steam
Beer
Caustic
Distillation
Water
Steam
Offspec Ethanol
Steam
Steam
Steam
Biogas Boilers
Molecular Sieve Drier
Caustic Recovery
Water
Cattle Feedlot
Ethanol
Caustic
Lime
Water
Polymer
Manure
Biogas
Aqueous Biosolids
Biosludge
Manure/Water
Anaerobic Biodigester
Waste Lagoon
Sludge Separation
Bionutrient Recovery
Aqueous Ammonia
Irrigation Water
Heating Water from Ethanol Process
Phosphoric Solids
Biosolids Slurry
Thin Stillage
Corn Husks Waste
Solids Composter
Compost
Backwash Solids to Lagoon
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For more information www.e3biofuels.com or call
913-441-1800