Comparative Assessment of Steam Processed pellets produced from wood, straw and switchgrass S M H ASSAN S HAHRUKH, A DETOYESE O YEDUN, A MIT K UMAR 1, L INOJ K UMAR, B AHMAN G HIASI, S HAHAB S OKHANSANJ 2 1 Department of Mechanical Engineering, University of Alberta Edmonton, AB, Canada 2 Department of Chemical and Biological Engineering, Vancouver, BC, Canada A DVANCED B IOFUELS S YMPOSIUM July , 2015, Montreal, Canada

Presentation Outline  Background and Objective  Pellet Production Supply Chain  Model Development and Validation  Mass and Heat Balance of Steam Pretreatment  Techno-Economic Result  Summary of Result Presentation at BFN, July, 2015

Background Presentation at BFN, July, 2015 Pretreatment helps producing high quality pellets Energy density of regular pellets is 1/8 th of coal High transportation cost of regular biomass and pellets Need for higher utilization of Biomass Low Utilization Cost Issues Pretreatment Low Bulk and Energy density of regular pellets

Objectives Conduct Techno-Economic Assessment Cost curves Sensitivity & uncertainty Conduct Energy Analysis Net energy ratio (NER) Sensitivity & uncertainty Develop process model for steam pretreatment of wood, straw and switchgrass Heat and mass balanceData intensive modeling Presentation at BFN, July, 2015

Pellet Supply Chain Biomass collection Bale formation/ chipping Transportation to pellet plant Pellet production Transportation of pellet to biorefinery Used in biorefinery Supply chain of pellet to a biorefinery (Conventional method) Used in biorefinery Biomass collection Transportation to pellet plant Pellet Production Transportation of pellet to biorefinery Steam pretreatment Bale formation /chipping Steam Pretreatment Supply chain of pellet (produced from pretreated biomass) to a biorefinery Presentation at BFN, July, 2015

Experimental Material and Method Material Wood, Straw,Switchgrass Moisture content ~ 10%-50% Method Pretreatment carried in 2.6L StakeTech Steam gun with 400g of biomass treated at different temperature and time Steam treated biomass pelletized Presentation at BFN, July, 2015

Model Input and Validation 1.Boiler unit: Supply of steam at different time and temperature 2.Time: 10 min 3.Temperature: ⁰C 2. Steam Pretreatment Unit: Biomass is treated with high pressure steam in batch reactor (Yield reactor considered) Governing Equation: Source: Lam et al Presentation at BFN, July, 2015

Model Input and Validation 3. Pellet mill: produces pellet of mm long, 6 mm in diameter, has a heating element operating at C. 2. Grinder: Kicks energy constant 100KJ/kg, solid recovery 95% 1.Dryer: operating temperature at 80 C. Presentation at ASABE, July,2015 No grinder is required for pellet production of straw and switchgrass

Model Validation Result Operation Experimental Energy Consumption (kJ) ASPEN model Predicted Energy Consumption (kJ) WoodStrawSGWoodStrawSG Steam Pretreatment Drying Size reduction Pelletization Presentation at BFN, July,2015

Comparative Heat and Mass Balance Presentation at BFN, July,2015 Wood A. Regular Pellet B. Steam Pretreated Pellet

Comparative Heat and Mass Balance (Cont’d) Presentation at BFN, July,2015 StrawSwitchgrass A. Regular Pellet B. Steam Pretreated Pellet

Variation of NER with Pretreatment Temperature and Level Presentation at BFN, July,2015

Uncertainty Analysis Presentation at BFN, July,2015 StrawSwitchgrass Wood

Techno-Economic Snapshot Presentation at BFN July,2015 StrawForest residue Switchgrass RegularSteam pretreated RegularSteam pretreated RegularSteam pretreated Optimum size (t year -1 ) 190,000250,000190,000290,000190,000230,000 Pellet cost ($ t -1 ) Capital recovery Maintenance cost Field cost Transportation cost Premium Employee cost Energy cost Consumable item cost Pellet transportation Total pellet delivery cost

Variation of Transportation Cost Presentation at BFN, July, 2015

Variation of Capital Cost Presentation at BFN, July, 2015

Variation in Production Cost Presentation at BFN, July,2015

Sensitivity Analysis - Wood Presentation at BFN, July,2015

Sensitivity Analysis - Straw Presentation at BFN, July,2015

Sensitivity Analysis - Switchgrass Presentation at BFN, July,2015

Uncertainty Analysis Presentation at BFN, July,2015 StrawSwitchgrass Wood

Summary of Result Energy Energy ratio of regular pelletization process is higher than steam pretreated pellet due to addition of steam as energy source Calorific value of pellet increases by 21% due to steam pretreatment Grinding energy input is zero for straw and switchgrass Cost $/tonne cost of production for steam pretreated pellet is higher than regular pellet due to increased capital cost $/GJ cost production of pellet for both steam treated pellet and regular pellet is similar with approximately 30 cents difference Scaling Steam pretreatment is more effective over a plant size of 270,000 tonnes/yr plant capacity due to economy of scale benefits based on $/GJ Presentation at BFN July, 2015

Acknowledgement  Bio Fuel Net  University of Alberta  Dr. Shahab Sokhansanj, Dr. Linoj Kumar and Bahman Ghiasi, Department of Chemical Engineering, University of British Columbia Presentation at BFN July,2015

T HANKS Contact Information: D r. A MIT K UMAR Professor NSERC/Cenovus/Alberta Innovates Associate Industrial Research Chair in Energy and Environmental Systems Engineering Cenovus Energy Endowed Chair in Environmental Engineering Department of Mechanical Engineering, University of Alberta CSBE | SCGAB Annual General Conference July 5 – 8, 2015, Edmonton, AB, Canada