Screening Protocol for Bioethanol Production from Lignocellulosics

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					       Cellulosic Ethanol:
Impact on Southern Ohio’s Future

               Frederick C. Michel, Jr.
                      Associate Professor
  Department of Food, Agricultural and Biological Engineering,
              The Ohio State University, OARDC
    “It is a sinister idea to transform food into fuel”.
Using food crops for biofuel is a “crime against humanity”
                  Jean Ziegler, UN Food Issues Research Chief


   “To ignore the urgency of global warming would be
        nothing less than criminally irresponsible”
                        Yvo DeBoer, UN Climate Official



                                         Wall Street Journal, 11/13/07
                         Outline
• What is Ethanol?
• The need for renewable fuels
• Sources of feed stocks for ethanol in Ohio
   – billion ton study
• Ethanol production from Ohio feedstocks
   – Herbaceous biomass
   – Woody biomass
   – Waste paper
• Conclusions
            What is Ethanol?
• An alcohol produced by fermentation of
  carbohydrates contained in biomass
• Contains 85% of the energy content of gasoline
• 113 octane versus 87 for regular unleaded
   – Allows higher engine efficiency than gasoline.
• Available as 85% (E85) and 10% (E10) blends
• Cleaner, more efficient burning than gasoline.
         Drivers for Renewable Fuels
• Fossil Petroleum consumption
   –   ~30% of energy used in the US is for transportation
   –   Petroleum provides 95% of US transportation energy
   –   140 billion gallons of gasoline used each year
   –   Known reserves essentially depleted in 30 years
   –   Prices predicted to rise until resource depletion
• Energy Independence and security
• Trade Imbalance
          Drivers for Renewable Fuels
• Green house gas emissions
   –   Fastest warming rate observed in millions of years
   –   Warming is accelerating
   –   Warming has been linked to greenhouse gas emissions
   –   The US accounts for 22% of the world’s CO2 emissions
   –   Transportation represents 32% of all US emissions
   –   Carbon emissions are projected to double by 2050
   –   Warming climate impacts predicted to be severe
     Florida
      circa
      2100
 (6-20 foot sea level rise
    caused by thermal
expansion and melting of
the Greenland Ice sheet)




    Overpeck, J.T., B.L. Otto-Bliesner, G.H. Miller, D.R. Muhs, R.B. Alley, and J.T. Kiehl.
    2006. Paleoclimatic evidence for future ice-sheet instability and rapid sea-level rise.
    Science 311: 1747-1750.
                  Why Biomass?
• Biomass is:
     •   Abundant
     •   Renewable carbon
     •   Carbohydrates can be fermented to ethanol fuel
     •   The only sustainable source of hydrocarbons
• Biomass is part of the solution when:
     • Coupled with conservation, increased vehicle
       efficiency and population stability can lead to
       sustainable, renewable fuel systems
               Corn Ethanol Carbohydrates

                    Starch: 70%–75% of corn
                     • Readily available and hydrolyzable
                     • Source of corn ethanol                                           OH

                                                                                             O
                                                           OH
                                                                               O
                                                                O                      HO
                                                                              OH
                              OH                                                                 OH
                                                                                                      O
                                                  O
                                   O                      HO             HO
 OH                                              OH
                                                                    OH
                                                                         O         O
                     O
      O                      HO
                    OH                      HO
                                       OH                                      OH
                                            O         O

HO             HO
          OH                                      OH
               O         O


                     OH
   Corn Grain Ethanol Process Diagram

       Corn grain handling




                                                CO2     Amylase enzymes
                    Ethanol                                 Yeast


                                       Steam



                                               Saccharification
                                                     &
Wastewater                Distillation &        Fermentation
Treatment              Ethanol Purification

      Wet or Dry
       Distillers
        Grain                                          Animal Feed
Corn Ethanol Biorefineries in the US
               Current    Under Construction
• US     4.9   B gal/yr    11.8 B gal/yr
• Ohio   -     B gal/yr     0.5 B gal/yr
        2006 Corn Ethanol Production
                Source www.ers.usda.gov and www.eia.doe.gov

• 146 billion gal/yr gasoline used in US
• 1.9 billion bushels of corn used for ethanol
    – 17% of US corn crop
•   4.9 billion gallons of ethanol produced from corn
    –   3 % of annual gasoline use
•   31 billion gallon potential supply if all corn used for ethanol
•   20% gasoline displacement maximum for corn ethanol

    => Other biomass feedstocks will be needed to displace gasoline
             Ohio Biomass Resource Potential
                            Corn and Wheat Grain



              Planted     Harvest     Yield     Production    Ethanol potential
               Acres       Acres      Bu/acre      Bu               gallons

Corn grain    3,150,000   2,930,000   161       471,730,000    318,417,750

Wheat grain    990,000     960,000      68       65,280,000      64,395,000

                                                        Source Hitzhusen et al., 2005

      At most corn could displace ~ 5.5% of Ohio’s current gasoline use
U.S. Biomass Resource Potential
• Billion Ton Study - developed by US DOE and USDA
• Over 1 billion tons/year of lignocellulosic biomass available
    • Forested areas not currently accessible are excluded.
    • All environmentally sensitive areas excluded.
• Potential to displace 30-50% of our gasoline
          Agricultural and Municipal Biomass
                        Billion ton study, Perlack et al., 2005
               200


                                             Together these feedstocks could be
               150
                                             used to displace 30% of gasoline.


Million        100
tons/yr

                50



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            Energy Required to Produce Fuels
                                                 From Biomass (Greenhouse gas nuetral)
                                                 From Coal and Natural Gas (adds GG)
                                                 From Petroleum (adds GG)
                   3

                                                                                      Fuel-to-Petroleum
Btus Required    2.5                                                                       Ratio = 10
 to produce
   Biofuels
                   2
     per
                          Fuel-to-Petroleum
Btu of Fuel at
                 1.5          Ratio = 0.9
  the pump

                   1


     Energy      0.5
      in the
       Fuel
                   0
                              Gasoline                         Corn                      Cellulosic
                                                              Ethanol                     Ethanol
                 Source: Wang, et.al., 2005. Well to Wheels Analysis of Advanced Fuel/Vehicle Systems
                    Integrated Corn Ethanol Biorefinery
                                                                                          Compost
       Corn grain handling                                                                  And
                                                                                       Liquid Fertilizer




                                                     CO2     Amylase enzymes
                    Ethanol                                      Yeast
                                                                               Steam

                                       Steam


                                                                               Methane
                                                    Saccharification
                                                          &
Wastewater                Distillation &             Fermentation
Treatment              Ethanol Purification

         Wet
                                                                                Anaerobic
       Distillers                Dairy and Cattle                 Manure
                                                                                Digestion
        Grain

                                    Milk and Meat
                         Cellulosic Ethanol
                                                                                                                                                                                                                         H
                                                                                                                                                                                                                          O               O
                                                                                                                                                                                                                                           H
Hemicellulose: 23%–32%                                                                                                                                                   H
                                                                                                                                                                          O                 O
                                                                                                                                                                                                           O
                                                                                                                                                                                                                    O
                                                                                                                                                                                                                                      O
                                                                                                                                                                                             H                     O
                                                                                                                           H                                O                      O               O                H
                                                                                                                            O                O                       O                              H
   • Xylose is the second most abundant                                    H                                O                       O
                                                                                                                                              H
                                                                                                                                                       O
                                                                                                                                                                    O
                                                                                                                                                                     H
                                                                            O                O                     O
     sugar in the biosphere                                                         O
                                                                                              H                   O
                                                                                                                                                        H
                                                          O            O                               O           H
                                                                                                        H
   • Polymer of 5- and 6-carbon                                       O
     sugars
                                                                                                                                                                                                                        HO
                                                                                                                                                                                                                                          O
                                                                                                                                                                                                  O                                        H
                                                                                                                                                                                                                                           O
                                                                                                                                                                                                   H
                                                                                                                                                                         H                             O            O        O
                                                                                                                                                                          O                 O                      O             HO
                                                                                                                                                   O                                         H
                                                                                                                                                                                             O                      H
                                                                                                                                                    H                                             O
                                                                                                                                                            O        O        O                    H            H
                                                                                                                           HO                                                                                    O                O
                                                                                                                                              O                     O             HO                                               O
                                                                                                                                                                                                                                   H
                                                                                                        O                                      H
                                                                                                                                               O                     H                      O
                                                                                                         H                                             O                                     H
                                                                                                             O          O       O                       H        HO                               O       O          O
                                                                               HO                                                                                                  O                     O
Cellulose: 38%–50%                                       O
                                                          H
                                                                  O        O        O
                                                                                                  O
                                                                                                   H
                                                                                                   O
                                                                                                        O
                                                                                                         H            H
                                                                                                                       O
                                                                                                                        H           H
                                                                                                                                     O        O
                                                                                                                                               H
                                                                                                                                                   O          O       O
                                                                                                                                                                                    H
                                                                                                                                                                                    O

                                                                                                                                                                                       O
                                                                                                                                                                                             O
                                                                                                                                                                                              H
                                                                                                                                                                                                       H
                                                                                                                                                                                                        O
                                                                                                                                                                                                          H              HO
                                                                                                                                                                                                                           O
                                                                                                                                                                                                                            O
                                                                                                                                                                                                                            H
                                                                          O                                            O              O                      O            H             H
                                                                           H            HO        O                                    O
                                                                                                                                       H                       H           O
                                                                                                   H                                                        HO                               O      O          O
                                                                                                                                              O
    • Most abundant carbon from in                        O
                                                           H           HO
                                                                                         O
                                                                                          O
                                                                                          H
                                                                                                        O
                                                                                                              O
                                                                                                               O
                                                                                                                H
                                                                                                                           O
                                                                                                                               HO
                                                                                                                                         O
                                                                                                                                          H
                                                                                                                                               H                            O
                                                                                                                                                                             H
                                                                                                                                                                             O
                                                                                                                                                                                       O
                                                                                                                                                                                                   O
                                                                                                                                                                                                    H              HO
                                                    O                                                                                         O         O       O                       H         HO
      biosphere                                      H
                                                         O
                                                                O
                                                                 O          O
                                                                                HO
                                                                                             O
                                                                                              H
                                                                                                   O
                                                                                                    H
                                                                                                             HO
                                                                                                                                 O
                                                                                                                                  H
                                                                                                                                  O
                                                                                                                                         O
                                                                                                                                                       O
                                                                                                                                                        H           H
                                                                                                                                                                     O        O
                                                                                                                                                                               H
                                                                                                                                                                                                                     O
                                                                                                                                                                                                                      H
                                                                                                                                                                                                                      O
                                                                  H                                                                       H                                            O      O        O
                                                               HO                                  O         O    O                                HO
    • Polymer of glucose                       O
                                                H
                                                    O
                                                     H                            O
                                                                                   O
                                                                                   H
                                                                                             O
                                                                                                            O
                                                                                                             H        HO         O
                                                                                                                                  H
                                                                                                                                                   O    O
                                                                                                                                                                      O
                                                                                                                                                                       O
                                                                                                                                                                       H
                                                                                                                                                                                  O
                                                                                                                                                                                   H
                                                                                                                                                                                             O
                                                                                                                                                                                              H            HO

                                                    O         O       O                       H         HO                               O
                                                             O                                                             O                      O         HO
    • Good biochemical feedstock               O
                                                H        H
                                                              H           HO        O
                                                                                     H
                                                                                             O      O        O
                                                                                                                            H
                                                                                                                            O
                                                                                                                                    O
                                                                                                                                     H
                                                                                                                                                   H

                                                          O                 O                      O             HO
                                          O                                  H
                                                                             O                      H
                                           H                                            O
                                               O      O       O                          H
                                                     O            H
                                                      H            O
                                          O
                                           H
                           Cellulosic Ethanol

Lignin: 15%–25%                       H CO                                                           H 3CO
                                       3
                                                                                                         O
   • Complex aromatic structure       HO
                                                                         OCH 3
                                                                 O
   • Very high energy content                         O
                                                                                       O CH 3 CH 3
                                                                                            O
   • Resists biochemical conversion                                OCH 3
                                                                                 O
                                                                                                OH
                                                                                                             O CH

   • Best used for combustion                                                                        O
                                                                                                         O
                                                                                 O
   • Soil amendment                          HO
                                                                                       HO
                                                                                       OH
                                                                                        H 3CO
                                             O CH 3                                  O CH 3


                                                              O CH 3 C H 3
                                                                   O
                                                          O                          O CH
                                                                       OH
                                                                             O
                                                                                 OH
                                                      O
                                                           HO
                                                           OH
                                                             H 3CO
                                                          OCH3
           Ohio Residue Resource Potential

                                                  Ethanol     Ethanol
              Gross Residue   Available Residue    Yield      potential
                 tons dry         tons dry        gal/ton      gallons

Corn stover      11,846,941        2,561,836        113      289,487,468
Wheat straw       3,438,377          896,266         99       89,536,973
Soy bean straw    4,781,700              -           -              -
LBS Soybean straw 9,563,400        4,781,700         91      435,134,700
Forest                             1,525,541        150      228,831,150
Wood waste          596,975          303,286         82       24,717,809
Paper waste                        6,058,259        116      702,758,044

TOTAL                             16,126,888                1,760,904,391

            Could displace ~ 28% of Ohio’s current gasoline use
Ohio Feedstocks
   Switchgrass
    2004, USDA-ARS Lincoln, NE



   Wheat Straw
    2004, Idaho National Lab, ID


   Large Biomass Soybean Straw (LBS)
    2005, USDA-ARS Beltsville, MD


   Recycled Office Paper
    2005, Caraustar Inc., OH
                 Feedstock Properties
        100                                                 Glucan
        90                                                  Xylan
        80                                                  Mannan
        70
 %                                                          Arabinan
        60
 dry                                                        Galactan
        50
basis                                                       Acetyl
        40
                                                            Other
        30
                                                            Lignin
        20
        10
         0
              Wheat   Switch     LBS     Soybean   Office
              straw   grass    Soybean    Straw    paper
                                Straw
          Lignocellulosic Ethanol Process Diagram

       Feedstock Handling                      Pretreatment                Solid/Liq Separation



                                                   Steam &
                                                     Acid
                                                                              Liquor                 Solids

                                             CO2     Enzymes,       Lime

                 Ethanol                                 Yeast
                                                                   Gypsum

                                    Steam



                                            Saccharification               Conditioning
                                                  &
Wastewater             Distillation &        Fermentation
Treatment           Ethanol Purification
                                                                Burner/Boiler
        Lignin                                                 Turbogenerator
       Residue                                                                           Steam



                                                                                       Electricity
          Research Background
• Pretreatment and enzymatic hydrolysis account for the
  greatest processing costs for lignocellulosic ethanol
  production
• Diverse feedstocks may vary greatly in the type, conditions
  and severity required for effective pretreatment

  Objective:
  Compare the relative reactivities of Ohio lignocellulosic
  feedstocks under a range of common pretreatment
  chemistries and severities
                Experimental Protocol
•   Central composite statistical design for each feedstock
•   Duplicate design for both acid (H2SO4) and base (NaOH) catalysts
•   Pretreat at 3 temperature, 3 times and 3 different catalyst loadings
     – severities of 2 to 3.6 (Overend and Chornet, 1987




•   Enzymatically saccharify washed pretreated solids for 96 hours
     – Combined cellulase and xylanase cocktail – 40 mg protein/g substrate
•   Analyze pretreatment and saccharification liquors by HPLC
     – monomeric and oligomeric sugars, furfural, HMF and acetate
•   Calculate “Relative Reactivity” for each feedstock under all conditions
                 Relative Reactivity

       Cellulose + Xylan release during Pretreatment and Digestion
RR =              Total initial Cellulose + Xylan
         Pretreatment Conditions
Temperature (oC)     150, 170, 190


Catalyst (g/g dry)   0.035, 0.070 H2SO4
                     0.035, 0.070 NaOH
                     Hot water, no catalyst

Time (min)           3, 6.5, 10 min

Severities           2 to 3.6
                         Sand bath 2
                         150, 170 or
                           190 C



                                       Sand
                                       bath 1
                                       220 C
Multiclave 10X reactor
             Components of Relative Reactivity
                        LBS Soybean straw
                     170 C., 6.5 min., 0.035 g/g

              70%
                                                   furfural
                                 Relative
              60%               Reactivity         HMF

              50%                                  Oligomeric Glucose
    %
                                                   Glucose
of initial    40%
cellulose                                          Oligomeric Xylose
              30%
 + xylan                                           Xylose
              20%

              10%

               0%

                      Acid   Neutral Alkaline
                    .035 g/g        .035 g/g

                             catalyst
         t= 6.5 min             LBS Soybean Straw




             100%


             80%


             60%
 Relative                                    yy
Reactivity
             40%


             20%                                                      190
                                                                    170
                                                                            Temperature
              0%                                              150
                    0.07 0.05 0.03 0.01 0.01 0.03 0.05 0.07
                                                                                (C)

                         Acid      Neutral        Base

                                  Catalyst (g/g)
                                  Wheatstraw




             100%


             80%


             60%
 Relative                                   yy
Reactivity
             40%


             20%                                                      190
                                                                    170
                                                                            Temperature
              0%                                              150
                    0.07 0.05 0.03 0.01 0.01 0.03 0.05 0.07
                                                                                (C)

                         Acid     Neutral        Base

                                Catalyst (g/g)
                                      Paper




             100%


             80%


             60%
 Relative
Reactivity
             40%


             20%                                                      190
                                                                    170
                                                                            Temperature
              0%                                              150
                    0.07 0.05 0.03 0.01 0.01 0.03 0.05 0.07
                                                                                (C)

                         Acid     Neutral     Base

                                Catalyst (g/g)
      Recycled Paper
enzymatic hydrolysis to sugars




                  +cellulase
                  +xylanase
                                                      Stark
                                 Wayne




TriCounty Solid Waste District
    1,000,000 tons MSW/y                 Tuscarawas
    ~250,000 tons paper/y
          Landfilled
        Cost ~ $30/ton
     25,000,000 gal EtOH
         (9% of use)
                  Paper to Ethanol Process Diagram
  Recycled Paper
    72.8% glucan                 waste treatment
    13.3% xylan                                                                                                       water
    5.3% lignin                                       water         buffer nutrients                                 recycle
     96% solids


                                     fed batch
Feed Processing
                                                               Saccharification        beer
                                                                   and                                  Filtration
                   purchased cellulase                          Fermentation
                              nutrients                                                                18 g/l EtOH

                                                                    3 day RT
                                                               fed batch 10% w/v
                    Glucose                                                            solids   Distillation/Dehydration
Saccharification                   Inoculum Prep                   15 FPU/g
                                                                                                        99% EtOH

                                                                    steam              steam
                                                                                                     Ethanol Storage

                                                      ash           Boiler
                                                 electricity
                                                                                                         Ethanol

                                                                   CO, off gas
                                                                     2
       Paper to ethanol costs
                Total ethanol cost 1.47     $/gal
                Plant size    28,809,582    gal/yr




                          Distillation
                             25%
                                              Feedstock
                                                41%




Boiler/Generator
                                   Enzyme
      11%
                                    13%
Saccharification/
 Fermentation
     3%                                           Labor,
                       Feed                      Overhead
                    Processing                     6%
                        1%
   Ethanol Cost as a function of Feedstock
            cost and Plant size

        4.5

        4.0
        3.5
        3.0
Ethanol 2.5
  Cost
 ($/gal) 2.0
         1.5
         1.0
         0.5                                                      75,000
                                                                100,000
                                                              250,000
         0.0                                                500,000          Plant
                                                          750,000
                 0                                     1,000,000             Size
                       20      40                    2,000,000             (ton/yr)
                                     60
                                          80   100
               Pape r Cost ($/ton)
          Forestry Products and Energy
• Paper
   • Cellulose fraction is more valuable than ethanol
• Ethanol
   • Extraction of hemicellulose and conversion to ethanol
• Gasification of wood and wood byproducts can be used to generate
   • Mixed alcohols for fuel use
   • Natural gas substitute for process heat at mills
• Combined heat and power using pelletized wood.
   • Fluidized bed combustion
   • Wood stove systems
                SUNY Hardwood Biorefinery Concept

                        Water Extraction
                                                          Extracted Woodchips
 Woodchips
                                                                (80 tons)
  100 tons
                                                           To Heat and Power
                 Hot
                                                               or Pulping
                Water
                250 C
                                                            Lignin
Lignin Separation                                           derived              Ethanol
                                                            products
                                                                                 10 tons
                        Sugars,
                        Acetate
                                         Lime

                                                                       Yeast
 Concentrated                                                    CO2
    Acetic
     Acid
    5 tons                                                                                 Steam
                              Nano
                            filtration
                                            Ca Acetate
                                                                                   Distillation &
                                                               Fermentation     Ethanol Purification
                                           Conditioning
                   Conclusions
• Ethanol has great potential as a renewable transportation fuel
• Corn ethanol can only supply a limited amount of fuel (<15%
  nationally, 6% in Ohio)
• Cellulosic biomass is the largest potential source of
  renewable fuel sufficient to supply a large fraction (>30%) of
  our current transportation fuel
• Conservation and efficiency increases of a similar magnitude
  will also be needed to achieve sustainable energy
  independence
• Bioethanol production from cellulosic feedstocks can be
  integrated with existing Ohio industries