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					Biochemical Processing Integration


   Biochemical Platform Review Meeting

             Daniel Schell
                NREL
            August 7-9, 2007
                                                           Overview
                                         Timeline                          Barriers
                                    • Project start date: FY2001   • Barriers addressed
                                    • Project end date: FY2012        – Biological process integration
                                                                      – Biomass variability
                                                                      – Biochemical/thermochemical
                                         Stage                          processing integration
                                    • Stage A/B                       – Cleanup/separations
                                      Exploratory/Development              Current Partners
                                         Budget                    • Subcontracts
                                $6,000
                                                                       –   Baylor University
Thousands of dollars per year




                                         FY06
                                $5,000   FY07                          –   Colorado State University
                                         FY08
                                $4,000
                                                                       –   Hauser Laboratories
                                                                       –   Glenn Murray, cheminformatics
                                $3,000                                     consultant
                                $2,000                             • Other collaborations
                                $1,000
                                                                       – MAST Center
                                                                       – CeraMem Corp. (CRADA)
                                   $0
                               Goals
    This Project Supports the Near-term
         Biochemical Platform Goal
• Near-term Goal: Make cellulosic ethanol cost competitive
  by 2012
   – Process Target: Competitive, moderate risk bioethanol technology tested at
     pilot scale (1 ton per day)
   – Cost Target: Data from integrated pilot operation combined with process
     design & cost estimate validates a $1.31 (2007$) per gallon ethanol selling
     price
                                    Objectives
• Generate integrated performance data identifying critical and
  showstopper issues
    – Provide process relevant information to R&D and industry developers to
      reduce risk by improving understanding of process chemistry and integrated
      performance
        • Near term objective (Sept. 07) to provide integrated performance data
        • Pilot Plant build out will enable broader variety of process options to be tested

• Develop state-of-the-art analytical tools to
  improve the accuracy and reliability of process
  measurements and yield calculations and
  techniques for on-line monitoring and process
  control
        Project Supports and Demonstrates Key
                   Technical Targets

R&D Area                     2008                         2010                         2012
Feedstock          Develop analytical methods   Develop analytical methods
                   for another feedstock        for another feedstock
Interface          accurate to 100% ± 5% mass   accurate to 100% ± 5% mass
                   balance closure              balance closure

Pretreatment                                                                  In IPO achieve > 90%
                                                                              xylan to xylose

Hydrolysate                                     Reduce sugar losses to <      In IPO reduce sugar
                                                2%                            losses to < 1% or
Conditioning                                                                  eliminate conditioning

Enzyme                                                                        Validate in IPO a
                                                                              $0.10/gal EtOH enzyme
Production                                                                    cost contribution

Enzymatic                                       Demonstrate >85% cellulose    In IPO achieve >85%
                                                to EtOH, >80% non-glucose     cellulose to EtOH and
Saccharification                                sugars to EtOH in 5 days at   >85% non-glucose
and Fermentation                                >20% total solids             sugars to EtOH in 3 days
                                                                              at >20% total solids

Integration        Complete rapid method for    Complete biochemical pilot    In IPO validate $1.31
                   measuring composition of     plant shakedown               (2007$) EtOH cost target
                   various process streams

                          IPO: Integrated Pilot Operation
                       Approach
                  Process Integration

Pilot and laboratory scale work to understand impact of
   integrated unit operations on process performance
               – Investigate integrated process performance
                   • Laboratory scale work using pretreated material produced
                     in pilot scale reactors
                   • New advanced enzymes
                   • Feedstock variability

               – Lower process cost (intensification)
                   • High solids
                   • Conditioning
                   • Water recycle

               – Understand environmental constraints
                   • Water use
                   • Waste streams

               – Facilitate industry and academia by supplying process
                 materials
   Process Material Supplied to Industry
     and Academia in Last Two Years

Materials            Lot Sizes     Total     Number of Contacts
                      (dry kg)   Supplied      (Lots) Supplied
                                  (dry kg)
                                             Industry   Academia


Corn Stover or        1-100        200          6          10
Switchgrass

Pretreated Corn      0.2-200       540         14          10
Stover

Enzymatically          1-4          7                      4
Hydrolyzed Residue
                          Approach
              Compositional Analysis Methods
    Develop and improve methods for wet chemical and rapid
analysis of biomass feedstocks and intermediate process streams

                   – Improve analytical methods for compounds in process
                     streams
                       • Accuracy and speed (robotics) for measuring sugars and other
                         products
                       • Other important measurements (e.g., total dry solids, insoluble
                         solids fraction)


                   – Validate/develop compositional analysis methods for
                     feedstocks
                       • Other feedstocks besides corn stover (e.g., switchgrass, etc.)
                       • Unknown compounds in biomass extractives


                   – Develop/improve rapid compositional analysis methods
                       • Intermediate process streams (e.g., in pretreatment reactors or
                         fermentors)
                       • On-line measurement and use on other instruments
Accomplishments

  Compositional Analysis Methods




  Process Integration
Accurate and Reliable Compositional
          Measurements

                       Process
                     Monitoring and
                        Control
     On-Line
  Characterization
                                                    Yield
  Quality Control
                                                 Calculations



                                                  Product
                                                  Residues
   Feedstocks


                                          Intermediate
                                      Solid/liquid Streams
Developing Tools to Understand Feedstock
   Composition and Process Chemistry



                    Unknown
                                    Making Progress on Measuring Lignin in
                                             Pretreatment Solids

                                         200          Samples are dilute acid pretreated stover produced in the pilot scale reactor

                                         180
MBC (%) or Lignin Composition (%, w/w)




                                         160
                                                                                                        Lignin Mass Balance Closure (MBC)
                                         140

                                         120

                                         100
                                                                                                                                                                  Wet Chemical
                                          80                                                                                                                      NMR


                                          60

                                          40                  Lignin Composition


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   Developed Faster Analytical Method for
   Measuring Ethanol and Other Products

• Fast HPLC analysis of fermentation products and furans
   – Analysis of multiple compounds in under 10 min versus 55 min by old method



                                                               Analysis time (minutes)
                            New Method
                                                              New Method Old Method
                                                Acetic acid        3            15
                                                Ethanol            5            22
                                                HMF                6            32
                                                Furfural           8            50

                Ethanol

                                         Old Method
                            Using Spectroscopy to Rapidly
                            Measure Biomass Composition
                                                                                             40




                                                                   Predicted (NIR/PLS) wt%
                                                                                             30



                                                                                             20

                                                                                                                             Glucan
                                                                                                                             Xylan
                                                                                             10                              Lignin
                            Corn Stover NIR Spectra
               1                                                                                                             Protein

                                                                                             0
             0.75                                                                                 0     10      20      30         40
                                                                                                      Actual (Wet Chemistry) wt%
Absorbance




              0.5                                              •         Spectra of biomass samples measured in a
                                                                         spectrophotometer
             0.25
                                                               •         Partial least squares analysis used to develop
                                                                         a calibration equation relating spectral
                                                                         information to component concentrations
               0                                               •         Requires a minimum of 50-100 samples to
                400   900           1400         1900   2400             develop a calibration equation
                               Wavelength (nm)
             Demonstrated On-line Feedstock
              Compositional Measurement
    • Near-infrared spectroscopy used to measure
      corn stover composition in real time
    • Light source and detector mounted above
      moving belt conveying ground stover
    • Explored effect of sensor height, particle size,
      ambient temperature and number of sub-scans
      on predicted composition
                                                              Light source and detector


FOSS Process                            • Only sensor height and to a lesser extent
Analytics Direct-                         temperature was found to effect predicted
Light 5000 NIR                            composition
System
                                        • Demonstrated feasibility of on-line compositional
                                          measurement of a difficult material

                                        • Site specific work will be required to implement in
                                          an industrial setting

                    Spectrophotometer
    Transferring NIR Calibrations to Other Instruments
     NIR calibration models have been developed for several
    feedstocks, including raw and pretreated corn stover; can
          these models be moved to other instruments?
•    Different NIR
     instruments                                                       Foss
     provide slightly
     different spectra of
     identical samples,
     caused by
     differences in         The “Calibration Transfer” Problem
     geometry and
     optics

•    Industrial partners
     and collaborators
     use different
     instruments; how
     can we move these
     calibration                                                 ASD
     equations among
     instruments?
    Successfully Transferred NIR Model Calibration
                      Equations

      NIR Difference Spectra Before and After Standardization
                                                                                    •   Calibration Transfer Algorithms
                                                                                        attempt to transform the NIR spectra
                                                                                        on secondary instruments to “look
                                                                                        like” they came from the primary
                                                                                        instrument; the more they resemble
                                                                                        the primary spectra, the better the
                                                                                        calibration transfer

                                                                                    •   We were able to use public-domain
                                                                                        calibration transfer algorithms to
                                                                                        successfully transfer the corn stover
    Calibration transfer algorithms: DS-Direct Standardization; PDS- Piecewise DS       calibration equation between two
                                                                                        very different NIR spectrometers



•   The loss in accuracy depends on the specific calibration transfer algorithm used

•   Different NIR software platforms incorporate different algorithms

•   There are no insurmountable issues with equation transfer between instruments
  Integration Studies Use High Solids Content
 Hydrolysate Produced in a Pilot Scale Reactor


95% Total Solids                              Pretreated at
                                              30% total solids




                           33% Total Solids
                           18% Insoluble Solids




        Water
                                       Hydrolysate
        Insoluble Solids

        Dissolved Solids
          Understanding Process Relevant Performance
              Baseline Integrated Performance Testing
                                                                                                                             70
                                     Water                     Lime
                                                                         From the 2002                                                                          Cellobiose
         Pretreated Corn                                                 base case                                           60                                 Glucose
              Stover                                                                                                                                            Xylose
                                             Liquid                      process design




                                                                                              Concentration (g/L)
                           S/L Separation              Lime Mixing
                                                                                                                             50                                 Ethanol
                                                                         (ref. Aden et al.)
                                   Solids
                                                                                                                             40
                                                       Acidification            Acid
Partially washed solids                                                                                                      30
recombined with liquor
conditioned by                                        S/L Separation            Gypsum                                       20
“overliming”
                                                                                                                             10
                                                          Mixing                 Water
                                                                                                                             0
                                                                                                                                  0          1           2             3             4
                                                      Saccharification          Enzyme
                                                                                                                                                     Time (d)

                                                                                                                             100
                                 Cells                 Fermentation             Nutrients                                     90




                                                                                                   Yield or Conversion (%)
                                                                                                                              80
                                                                                                                              70
                                                           Ethanol
       Cellulose hydrolyzed at 20%                                                                                            60
       total solids with Genencor                                                                                             50
       Speyzme (40 mg/g, 45C, pH 4.8,                                                                                        40
       4 days) followed by fermentation                                                                                       30
       with a recombinant glucose-                                                                                            20
       xylose fermenting bacteria (Z.                                                                                         10
       mobilis 8b, 35C, pH 5.0, 4 days)                                                                                          0
                                                                                                                                       Cellulose   Xylose Consumed   Ethanol Yield
                                                                                                                                      Conversion
Aden et al. 2002. NREL. NREL/TP-510-32438. http://devafdc.nrel.gov/bcfc/oraclefind3.cgi?6483.
                     Early Findings

Only half of the available sugars in a 20% (w/w) total
   solids hydrolysate were converted to ethanol


   • Sugar losses during conditioning
   • Poor xylose utilization
      – Microorganism limitation or toxicity or both
   • Large amount of remaining glucose
      – As monomers and oligomers
   • Didn’t look at recycle water
   • Large enzyme requirement (40 mg protein/g cellulose)
Reduced Sugar Losses During Conditioning
                                     Effect of a Different Conditioning Agent
                                   Ethanol Yield   Overall Ethanol Yield   Sugar Recovery
                         100


                              90                                                            •   Beside reduced sugar
Yield or Sugar Recovery (%)




                                                                                                losses, ethanol yields
                                                                                                increased for NH4OH-
                                                                                                based conditioning
                              80

                                                                                            •   This simpler process
                              70                                                                may eliminate the solid-
                                                                                                liquid separation step,
                                                                                                but chemical cost will
                                                                                                increase
                              60

                                                                                            •   Represents significant
                              50                                                                progress toward
                                                                                                achieving the 2012 goal
                                                                                                of < 1% sugar losses
                              40
                                             1                               2
                                      Overliming                Ammonium Hydroxide
                      100
                                               87        84
                                                                                                                             Hydrolysate Strength Significantly
                              A        79
                                                                              85   81
                                                                                                                             Impacts Performance
Ethanol Yield (%)




                       75         68


                                                                     58
                        50


                                                                                                                                                                                                              Glucose fermenting yeasts:
                        25
                                                    Design-Expert® Software                                                                                                                                   Saccharomyces cerevisiae D5A (S.c.
                                                        49
                                                    Ethanol Yield                                                                                                                                             D5A) and a Broin commercial yeast
                                                                                                                          21% Equivalent Total Solids
                           0
                    Ov erliming
                                                    X1 = B: Conditioning
                                                    X2 = D: Strain                                        S.c. D5A
                                                                                                                                                                                                              (Broin S.c.); yield based on glucose
                                                    Actual Factors
                                                    A: Hydrolysate Strenght = 65.00
                                                                                    Broin S.c.                                                                                                                Glucose-xylose fermenting microbes:
                                                    C: Added Glucose = 100 Z. m. 8b                                                 84        80
                                                                                           100                                                                                                                Zymomonas mobilis 8b (Z.m. 8b) and
                                        Neutralization              P.s.
                                                                                                                 B                                                  82           77
                                                                                                                                                                                                              Pichia stipitis (P.s.); yield based on
13% Equivalent Total Solids                                                                                                                                                                                   glucose + xylose
                                                                                   Ethanol Yield (%)
                                                                                                          75

                                                                                                                            47

                                                                                                           50
                                                                                                                     34
                                                                                                                                                   Design-Expert® Software

                                                                                                           25                                      Ethanol Yield

                                                                                                                                                   X1 =27Conditioning
                                                                                                                                                        B:
                                                                                                                                                                                                                        28% Equivalent Total Solids
                                                                                                                                                   X2 = D: Strain

                                                                                                              0                           16       Actual Factors
                                                                                                       Ov erliming                                 A: Hydrolysate Strenght = 85.00    S.c. D5A
                                                                                                                                                   C: Added Glucose = 100                   100                                     82        77
                                                                                                                                                                            Broin S.c.


                                                                                                                             Neutralization            P.s.
                                                                                                                                                                   Z. m. 8b
                                                                                                                                                                                                                    C                                      79
                                                                                                                                                                                                                                                                     74




                                                                                                                                                                                      Ethanol Yield (%)
                                                                                                                                                                                                             75



                        •         Glucose-xylose fermenting microorganisms are                                                                                                                                50
                                  more negatively impacted by increasing                                                                                                                                                    23

                                  hydrolysate strength                                                                                                                                                        25

                        •         Performance was slightly better in overlimed                                                                                                                                          8


                                  hydrolysate than neutralized hydrolysate                                                                                                                                       0
                                                                                                                                                                                                          Ov erliming                                                     S.c. D5A
                                                                                                                                                                                                                                                   2
                                                                                                                                                                                                                                                                 Broin S.c.
                                                                                                                                                                                                                                          0
                                                                                                                                                                                                                                                          Z. m. 8b
                                                                                                                                                                                                                             Neutralization        P.s.
        High ethanol concentrations can be
       achieved in concentrated hydrolysates

         28% equivalent total solids hydrolysate liquor
             supplemented with 200 g/L glucose                                              •   Glucose fermenting
100                                                                                             yeast can achieve
                                              S. cerevisiae D5A
90
                                                                                                good performance in
                                              Broin S. cerevisiae
                                              S. pastorianus (26602)
                                                                                                concentrated
80                                                                                              hydrolysate
70

60                                                                                          •   Still need to achieve
50                                                                                              higher ethanol
                                                                                                yields, performance
40
                                                                                                is being limited
30

20                                                                                          •   Need to take
10                                                                                              advantage of
                                                                                                microorganisms
 0
      Glucose Consumed   Metabolic Ethanol   Ethanol Yield (%)      Ethanol Concentration       strengths
             (%)             Yield (%)                                      (g/L)
                  Progress Toward Higher Ethanol Yields
                                                                                                        80




                                                                            Overall Ethanol Yield (%)
                            Water                     Lime                                              70
Pretreated Corn
     Stover                         Liquid                                                              60
                  S/L Separation              Lime Mixing

                                                                                                        50
                          Solids                                                                                                   Baseline       Whole
                                              Acidification     Acid                                    40                         Oct. 05        Slurry
                                                                                                                                                  Dec. 06
         Baseline                                                                                       30
                                                                                                                                    Process Configuration
                                                                                                                                               1
         Process                             S/L Separation     Gypsum
                                                                                                             Pretreated Corn Stover



                                                 Mixing          Water

                                                                                                                 Conditioning                 NH4OH


                                             Saccharification   Enzyme

                                                                                                                pH Adjustment                  Acid

                        Cells                 Fermentation      Nutrients
                                                                                                                                                     Whole
                                                                                                                                                     Slurry
                                                                                                                Saccharification              Enzyme
                                                  Ethanol
                                                                                                                                                     Process

                                                                 Cells                                           Fermentation                 Nutrients
      Test Conditions
      Microorganism: Z. mobilis 8b
      Enzyme Loading: 40 mg protein/g cellulose
      Equivalent total solids: ~20% (w/w)
                                                                                                                    Ethanol
                     Progress Toward Higher Ethanol Yields
                                                                                                                                Water                          NH4OH
 •      Making progress toward demonstrating
        the 2012 sugar conversion targets   Pretreated Corn Stover                                                                        Liquid
                                                                                                                       S/L Separation                Conditioning
          –       85% cellulose to ethanol
                                                                                                                                Solids
          –       80% non-glucose sugars to ethanol
                                                                                                                                                                               Nutrients
                                                                         Caustic                                       pH Adjustment                 Fermentation
                              Water                     Lime                                                                                                                     Cells

Pretreated Corn
     Stover                           Liquid
                    S/L Separation              Lime Mixing
                                                                           Enzyme                                      Saccharification
                                                                                                                                                        Ethanol
                                                                                                                                                                  Separate
                            Solids                                                                                                                                C5/C6
                                                Acidification     Acid
                                                                              Cells                                     Fermentation               Nutrients      Process
                                               S/L Separation     Gypsum

                                                                                                                            Ethanol
      Baseline
                                                   Mixing          Water                                          80
      Process

                                                                                      Overall Ethanol Yield (%)
                                                                                                                  70                                                Separate
                                               Saccharification   Enzyme
                                                                                                                                                                    C5/C6*
                                                                                                                  60                                                June 07
                          Cells                 Fermentation      Nutrients
                                                                                                                  50                               Whole
                                                                                                                                      Baseline     Slurry
                                                    Ethanol                                                       40                  Oct. 05      Dec. 06
       Test Conditions
                                                                                                                  30
       Microorganisms: S. cerevisiae D5A and Z. mobilis 8b                                                                                 Process Configuration
                                                                                                                                                      1

       Enzyme Loading: 40 mg protein/g cellulose
       Equivalent total solids: ~10-15% (w/w)                                                                           *Preliminary result, no fermentation broth reuse
                               Good Performance with Water Recycle is a Key
                                                 Issue
                                    Hydrolysate liquor conditioned by overliming and
                                    fermented using a glucose-xylose Z. mobilis 8b
                              100                                                              •   Recycle water (stillage
                                      7.5 g/L
                                                                          Ethanol Yield            bottom stream) is a common
                               90                         12.0 g/L        Glucose Conversion       method of reducing fresh
                                                                          Xylose Conversion
                               80
                                                                                                   water use
                                                                                                    – Our economic models
                                                                                                      assume 25% recycle
Yield (%) or Conversion (%)




                               70

                                                                        10.0 g/L
                               60
                                                                                               •   Performance is significantly
                               50                                                                  affected at modest solid
                                                                                                   concentrations and recycle
                               40
                                                                                                   water use
                               30

                                                                                               •   Other inhibitors in addition to
                               20
                                                                                                   acetic acid are responsible
                               10                                                  13.0 g/L        for the poor performance

                               0                                                               Steady state acetic acid concentrations
                                     10% Solids    10%Solids     25% Solids    25% Solids
                                     10% Recycle   25% Recycle   10% Recycle   25% Recycle
 Possible Solutions to Water Recycle


• Remove acetic acid using membranes
   – Initial effort via subcontract with Colorado State
     University
• Remove other inhibitory compounds
   – Initial effort via the MAST Center
• Other clean up/separations technologies



                       The MAST Center is a National Science Foundation
                       Multi-site Industry/University Cooperative Research
                       Center, with sites at the University of Colorado and the
                       University of Cincinnati.
    Success Factors and Showstoppers

• Critical success factors and showstoppers are aligned
  with Biochemical Platform technical barriers
   – Integration specific issues, i.e., achieving good conversion yields
     at process relevant operating conditions
       •   Operating at high solid concentrations
       •   Minimizing water use (recycle water)
       •   Minimizing conditioning requirements
       •   Understanding other environmental constraints
             – Liquid and gaseous emissions
   – Accurate and reliable laboratory and on-line compositional
     measurements
       • Yield calculations and mass balance closure
       • Process monitoring and control
    Future Work Aligned with Program Targets
         2012 Target: Pilot scale demonstration of technology
 R&D Area          Current          2007       2008               2009                     2010                2011                2012

 Integration/    Research state-           Complete          Completed              1) Biochemical pilot   Provide         Data from integrated
 Modeling       of-technology              rapid analysis    biochemical           facility shakedown      equipment       pilot operation
                utilizing current          method to         pilot facility with   completed (For          and operating   combined with
                data and                   predict           2 or more             NREL, demonstrated      costs for the   process design & cost
                modeling shows             component         pretreatment          by successful           corn stover     estimate validates a
                a $2.47/gal                concentration     trains and            operation of new        $1.31/gal       $1.31/gal ethanol
                ethanol selling            s in pretreated   occupancy             pretreatment train(s)   baseline to     selling price and
                price with total           slurry stream     formally              on corn stover)         develop cost    capital cost of
                capital of                 to same           handed over to                                correlations    $1.83/gal of annual
                $2.94/gal of               accuracy as       operating entity      2) Process cost         for 2 other     installed capacity for
                annual installed           wet chemistry                           estimate updated with   feedstocks      nth plant (adjusted to
                capacity (2002$)           methods                                 latest data and                         the current cost year
                                                                                   engineering                             from 2007$) for corn
                                                                                   consultations                           stover



• Produce pilot scale integrated performance
  data using the new pilot plant facility to
  demonstrate the 2012 cost target
      – Focus on integration specific issues and
        2012 targets along the way
      – Test newly developed enzymes
      – Understand effect of feedstock variability on
        process performance (with Feedstock
        Interface Task)                                                                                      Pilot Plant Expansion
   Future Work Aligned with Program Targets
                                   Biomass Analytical Methods
R&D Area          Current          2007       2008               2009                     2010                2011                2012

Integration/    Research state-           Complete          Completed              1) Biochemical pilot   Provide         Data from integrated
Modeling       of-technology              rapid analysis    biochemical           facility shakedown      equipment       pilot operation
               utilizing current          method to         pilot facility with   completed (For          and operating   combined with
               data and                   predict           2 or more             NREL, demonstrated      costs for the   process design & cost
               modeling shows             component         pretreatment          by successful           corn stover     estimate validates a
               a $2. 47/gal               concentration     trains and            operation of new        $1.31/gal       $1.31/gal ethanol
               ethanol selling            s in pretreated   occupancy             pretreatment train(s)   baseline to     selling price and
               price with total           slurry stream     formally              on corn stover)         develop cost    capital cost of
               capital of                 to same           handed over to                                correlations    $1.83/gal of annual
               $2.94/gal of               accuracy as       operating entity      2) Process cost         for 2 other     installed capacity for
               annual installed           wet chemistry                           estimate updated with   feedstocks      nth plant (adjusted to
               capacity (2002$)           methods                                 latest data and                         the current cost year
                                                                                  engineering                             from 2007$) for corn
                                                                                  consultations                           stover




                                            • Develop rapid on-line methods for feedstocks
                                              and intermediate process streams
                                                     – Initial focus on pretreated stream

                                            • Improve wet chemical analysis techniques for
                                              more accurate yield and mass balance
                                              calculations
                                Summary

•   This project explores integrated process performance with a focus
    on achieving the 2012 Program goals for a pilot scale process
    demonstration
    – Key 2012 Targets
        • >90% xylan to xylose
        • > 85% cellulose and non-glucose sugars to ethanol
        • Validate in integrate pilot operation $1.31 ethanol cost target

    – Provides practical knowledge of integrated system performance as
      well as identifying critical process issues and knowledge gaps
        • Operation at process relevant conditions
        • Recycle and emissions

    – Develops state-of-the-art analytical tools to improve the accuracy and
      reliability of process measurements and yield calculations and
      techniques for on-line monitoring and process control
               Summary (cont.)

• Recent Accomplishments
  – Reduced/eliminated sugar losses during
    conditioning to 1-2%
  – Achieved high ethanol concentration (~90 g/L) in
    glucose-supplemented hydrolysate liquor
  – Demonstrated on-line measurement of corn
    stover composition
  – Improved measurement of lignin in pretreated
    materials improving lignin mass balance closure
    from 165% to 124%
                       Summary (cont.)
• Future Work
  – Integrated process performance
      • Identify and address critical issues (e.g., waste water
        recycling ) and processing requirements on the way to
        achieving pilot scale performance targets
      • Evaluate new enzymes
  – Initiate new work in separation technology
      • Investigate efficacy of membranes to improve process
        performance

                                         – Develop on-line rapid compositional
                                           measurement techniques
                                              • For feedstock, pretreated,
                                                enzymatically saccharified and
                                                fermented process streams
                                         – Improve compositional methods
                                              • For lignin and sugars in hydrolysate
                                                liquors
Questions?
Feedback from Previous Project Reviews
 • Interim Stage Gate Review Meeting held September 2004
 • Selected Feedback
    – Develop on-line monitoring capability, especially for monitoring the
      enzymatic saccharification reactor and a second area for
      application of on-line monitoring would be in the fermentation
      reactor.
        • Objective is in 2012 targets, this one due in FY08

    – Need to extend the variability studies to determine the impact of
      corn stover variability on pretreatability (sugar yields), enzymatic
      cellulose hydrolysis, and fermentability.
        • Work being done this year

    – Examining the gypsum question is low priority and should not be
      undertaken.
        • No new work was undertaken

    – Enzymatic saccharification time is too long and needs to be
      characterized with unwashed materials, that is, with background
      components (non-sugars) present during enzymatic
      saccharification.
        • Work was performed in Pretreatment and Enzymatic Hydrolysis Task
                             2012 Targets by R&D Area
R&D Area         Current                   2007                    2008                  2009                   2010                  2011                   2012
Feedstock      Corn Stover         Determine which            Develop/adapt        Define the             Develop/adapt dry      Define the          Develop cost
                                   feedstock types will be    dry corn stover      relationships          corn stover            relationships       correlations for two
Interface
                                   used in pioneer plants     analytical           between variations     analytical methods     between             other feedstocks
                                   and have the potential     methods for          in the feedstock       for diverse            variations in the   based on the corn
                                   to provide significant     diverse samples      composition and        samples (>3) of        feedstock           stover $1.31/gal
                                   volumes (>100 million      (>3) of another      key processing         another feedstock      composition and     baseline
                                   tons/year)                 feedstock type       parameters             type (e.g. ensiled     key processing
                                                              (e.g. switchgrass)                          corn stover)           parameters
                                                              achieving mass                              achieving mass
                                                              balance closure                             balance closure of
                                                              of 100% ± 5%                                100% ± 5%

Pretreatment   63% xylan yields    1) Achieve 75% xylose      Validate > 75%       1) Understand          1) Acheive > 85%       Provide bench       Achieve >90% xylan
               and 13% sugar       yield in laboratory        xylan yield & <      sugar degradation      xylan yields and <     scale               to xylose & < 5% xylan
               degradation in      scale high solids          8% degradation       kinetics & how to      6% sugar               pretreatment        degradation from corn
               continuous          pretreatment reactor       from corn stover     reduce degradation     degradation from       data on two other   stover in integrated
               reactor with        on corn stem               using a              to < 6% for corn       corn stover using a    feedstocks (e.g.    pilot operation with >
               >30% solids         internode                  continuous           stover                 continuous reactor     switchgrass,        30% solids
                                                              reactor                                     with > 30% solids      ensiled corn
                                   2) Define the                                   2) Test accessory                             stover) to
                                   relationships between                           enzymes' effect on     2) Make final          develop cost
                                   pretreatment                                    reducing               decision on            correlations
                                   conditions and the                              pretreatment costs     pretreatment           against the corn
                                   chemical/ultrastructura                         for corn stover in     process to use in      stover baseline
                                   l changes in corn                               lab equipment          2012 pilot
                                   stover stems that                                                      operation
                                   result in biphasic xylan
                                   hydrolysis

Hydrolyzate    13% sugar losses                               Define the           Reduce sugar           Reduce sugar           Provide bench       Reduce sugar losses
               in overliming                                  relationships        losses in corn         losses in corn         scale               in corn stover
Conditioning
               conditioning step                              between corn         stover hydrolyzate     stover hydrolyzate     conditioning data   hydrolyzate
                                                              stover               conditioning step to   conditioning step to   on two other        conditioning step to <
                                                              hydrolyzate          < 7% in laboratory     < 2% in laboratory     feedstocks (e.g.    1% in integrated pilot
                                                              conditioning and     equipment              equipment              switchgrass,        operation or eliminate
                                                              fermentation         (accessory                                    ensiled corn        need for conditioning
                                                              performance in       enzymes is one                                stover) to
                                                              lab equipment        option)                                       develop cost
                                                                                                                                 correlations
                                                                                                                                 against the corn
                                                                                                                                 stover baseline
                            2012 Targets by R&D Area
R&D Area             Current                2007                 2008                  2009                   2010                      2011                      2012
Enzyme             $0.32/gallon of     Develop the first   1) Baseline            Conduct targeted     1) Define cellulase      Validate the cost          Validate a $0.10/gal
                   Ethanol             generation          commercial             substitutions of     interactions at the      contribution of            cost contribution of
Production
                                       computational       cellulases' specific   cellobiohydrolase    plant cell wall          purchased enzyme at        purchased enzyme
                                       model of CBH I      activity               to increase          2) Validate the cost     $0.10/gal EtOH             used in integrated
                                       capable of          2) Determine how       specific activity    contribution of                                     pilot operation
                                       describing          cellulase enzymes      by 2-fold relative   purchased enzyme
                                       structure and       move along             to native            at $0.16/gal EtOH
                                       function, and       cellulose chains
                                       verify CBH I
                                       structure

Enzymatic          > 85%                                   Demonstrate >          Define the           Demonstrate > 85%        1) Demonstrate > 85%       Demonstrate > 85%
                   Cellulose to                            85% cellulose to       relationships        cellulose to EtOH, >     cellulose to EtOH, >       cellulose to EtOH, >
Saccharification
                   EtOH, > 75%                             EtOH, > 80%            between lignin       80% non-glucose          85% non-glucose            85% non-glucose
and                xylose to EtOH,                         xylose to EtOH, >      redeposition and     sugar to EtOH in a       sugar to EtOH in a         sugar to EtOH in a
Fermentation       0% other                                40% other sugars       enzyme kinetics      total of 5 days in lab   total of 3 days in lab     total of 3 days in
                   sugars to EtOH                          to EtOH in a total                          equipment with >         equipment with > 20%       integrated pilot
                   in a total of 7                         of 7 days in lab                            20% total solids         total solids               operation with > 20%
                   days in lab                             equipment with >                                                     2) Develop bench           total solids
                   system with >                           20% total solids                                                     scale SSF data on two
                   20% total solids                                                                                             other feedstocks
                                                                                                                                (switchgrass, ensiled
                                                                                                                                corn stover) to
                                                                                                                                develop cost
                                                                                                                                correlations against
                                                                                                                                the corn stover
                                                                                                                                baseline

Integration/       Research state-                         Complete rapid         Completed            1) Biochemical pilot     Provide equipment          Data from integrated
                   of-technology                           analysis method to     biochemical pilot    facility shakedown       and operating costs        pilot operation
Modeling
                   utilizing current                       predict component      facility with 2 or   completed (For           for the corn stover        combined with
                   data and                                concentrations in      more                 NREL, demonstrated       $1.31/gal baseline to      process design &
                   modeling                                pretreated slurry      pretreatment         by successful            develop cost               cost estimate
                   shows a                                 stream to same         trains and           operation of new         correlations for 2 other   validates a $1.31gal
                   $2.47/gal                               accuracy as wet        occupancy            pretreatment train(s)    feedstocks                 ethanol selling price
                   ethanol selling                         chemistry methods      formally handed      on corn stover)                                     and capital cost of
                   price with total                                               over to operating    2) Process cost                                     $1.83/gal of annual
                   capital of                                                     entity               estimate updated                                    installed capacity for
                   $2.94/gal of                                                                        with latest data and                                nth plant (adjusted to
                   annual installed                                                                    engineering                                         the current cost year
                   capacity                                                                            consultations                                       from 2007$) for corn
                   (2002$)                                                                                                                                 stover
                      Base Case Process Flow Diagram
                                                 Water Losses                    Steam                            Vent (to WWT)                           Recycle Water                      Lime


Corn Stover                                            Shredded
                                                        Stover                                                                                                      Liquid
                                 Feed Handling                         Pretreatment                        Flashing                            S/L Separation                       Lime Addition
 (77%)                                                     (60%)                         (30%)                                (37%)

                                                                                                                                                          Solids

                                                                                                                                                                                    Acidification     Acid
                                                      Acid
                                                                        Acid Mixing




                                                                                                                                                                                   S/L Separation     Gypsum




                                                                                                                                                                                       Mixing         Recycle
                                                                                                                                                                                                       Water
                                                                                                                 Process Water                                                             (20%)


                                                                                                                                           Cell Production                         Saccharification   Enzyme
                                                                                                 Condensate
To WWT
                                                                                                 Syrup                        Well Water           Vent
                                                           To Boiler
                                                                                                                                                                      Vent
                                                                                                    2nd and 3rd Effect Evp.                   Scrubbing                             Fermentation      Nutrients
                        Treated                    Well
                         Water                     Water                      Solids                                                                               Liquid Return
                                                                                                                Vapor
                                                                                                                                                                      Vent
Recycle                                                                                                                                    Bottoms (with solids)
                                       Mixing                          S/L Separation               1st Effect Evaporation                                                            Stripping
 Water                                                      Liquid




                                                                                                                                                                                    Rectification
                                                                                                                                           Bottoms



2002 Base Case Design
Corn Stover – Dilute Acid Pretreatment – Enzymatic Hydrolysis                                                                                                                        Mole Sieve



Values in parenthesis are solid concentrations                                                                                                                                              Ethanol
Background on Process Calculations


                 Conditioning           Fermentation

                                             CO2
     Sugars

                                           Ethanol

                                                     By-Products
                                                     Unconverted Sugar

   Hydrolysate


                                Sugar Degradation Products
                                (Losses)
 Yield and Loss Calculations


              Conditioning           Fermentation

                                          CO2
  Sugars

                                        Ethanol

                                                  By-Products
                                                  Unconverted Sugar

Hydrolysate


                             Sugar Degradation Products
                             (Losses)

                    Sugar Losses
   Yield and Loss Calculations
                                                     Ethanol Yield

                        Conditioning           Fermentation

                                                    CO2
    Sugars

                                                  Ethanol

                                                            By-Products
                                                            Unconverted Sugar

 Hydrolysate


                                       Sugar Degradation Products
                                       (Losses)
Overall Ethanol Yield
  Yield and Loss Calculations


                        Conditioning           Fermentation

                                                    CO2
    Sugars

                                                  Ethanol

                                                            By-Products
                                                            Unconverted Sugar

 Hydrolysate


                                       Sugar Degradation Products
                                       (Losses)
Overall Ethanol Yield
                                          Publications
•   Schell, D.J. et al. “National Bioenergy Center Biochemical Platform
    Integration Project Quarterly Newsletter,” NREL, distributed quarterly.

•   Bower, S., Wickramasinghe, R., Nagle, N.J. Schell, D.J. 2008. “Modeling
    sucrose hydrolysis in dilute sulfuric acid solutions at pretreatment
    conditions for lignocellulosic biomass,” Bioresource Technol. In
    Press.

•   Schell, D.J., Dowe, N., Ibsen, K.N., Riley, C.J., Ruth, M.F., Lumpkin, R.E.
    2007. “Contaminant occurrence, identification and control in a pilot-
    scale corn fiber to ethanol conversion process,” Bioresource Technol.
    98, 2942-2948. In Press.

•   Zhang, P., Schell, D.J., McMillan, J.D. 2007. “Methodological analysis for
    determination of enzymatic digestibility of cellulosic materials,”
    Biotech. Bioeng. 96, 188-194.

•   Chen, S. F.; Mowery, R. A.; Scarlata, C. J.; Chambliss, C. K. 2007.
    “Compositional Analysis of Water-Soluble Materials in Corn Stover,” J.
    Agric. Food Chem. 55, 5912-5918.

•   Mohagheghi, A., Ruth, M., Schell, D.J. 2006. “Conditioning
    hemicellulose hydrolysates for fermentation: Effects of overliming pH
    on sugar and ethanol yields,” Process Biochemistry, 41, 1806-1811.

•   Katzen, R., Schell, D.J. 2006. “Lignocellulosic Feedstock Biorefinery:
    History and Plant Development for Biomass Hydrolysis,” in
    Biorefineries – Industrial Processes and Production: Status Quo and
    Future Direction, Vol. 1, Eds. Kamm, B., Gurber, P., Kamm, M., Wiley-
    VCH Verlag GmbH & Co., Weinhein, Germany, 129-136.

				
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