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Thermochemical Conversion of Forest Thinnings March 8 th , 2005 – Thesis Defense –

Thermochemical Conversion of Forest Thinnings March 8 th , 2005 – Thesis Defense –. Agenda. Thinning of Forests Bio-fuel Production Comparison of Alternatives Conclusions. Agenda,02-07-05,PYR. Many forests in the western US are at elevated risk to wildfire. Forest or Tinderbox?

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Thermochemical Conversion of Forest Thinnings March 8 th , 2005 – Thesis Defense –

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  1. Thermochemical Conversion of Forest Thinnings March 8th, 2005 – Thesis Defense –

  2. Agenda • Thinning of Forests • Bio-fuel Production • Comparison of Alternatives • Conclusions Agenda,02-07-05,PYR

  3. Many forests in the western US are at elevated risk to wildfire Forest or Tinderbox? - Western US Forests - • Periodic natural fires regenerate the forest ecosystem by burning out brush and small diameter trees • Decreased competition among remaining trees • Returns nutrients to soil • Years of active fire suppression on private and public land in the west have led to unnaturally high forest fuel loads • Small-diameter trees (<6” diameter) • Brush • Dead wood • High fuel density enables ‘wildfires’ • Burns hotter than natural fires • Can consume both large and small trees • Long eco-system recovery • Expensive to fight • Dangerous for firefighting personnel • As of 2002, the US Forest Service listed 120 million acres at “unnatural risk” for wildfire 010,02-07-05,PYR.ppt

  4. One way to reduce the risk of wildfire is to mechanically thin overstocked forests Mechanical Thinning - Overview - Mechanical Thinning Before – High Risk Forest After – Thinned Forest • Mechanical thinning involves the removal of small diameter trees to create a more natural forest • Simulate end-state of a natural burn • Numerous benefits to thinning include: • Decreased risk of wildfire • Improved resistance to insect infestation and disease • Remaining trees grow larger and faster due to decreased competition • However, thinnings have little traditional commercial value • Thinning can not pay for itself (unless combined with commercial logging – highly contentious) • So what do you do with all the material you remove from the forest? Source: Reynolds Forestry Consulting - RFC, Inc 011,02-07-05,PYR.ppt

  5. Thinnings have a number of energy and non-energy uses Uses for Thinnings - Overview - Energy Uses Non-Energy Uses • Wood chip cogeneration • Production of power and low-grade heat or steam from wood chips • Co-fire • Substitute wood chips for fraction of coal at conventional power plant • Produce a bio-fuel • Methanol: commodity chemical, transportation fuel • Bio-oil: industrial fuel, refining feedstock • Wood Pellets: residential fuel • Pulp and paper • Forest products • Emerging small-wood industries • OSB production at small scale • Long-term carbon capture opportunity • Disposal • Landfill • Pile burning 012,02-07-05,PYR.ppt

  6. Of special interest are “stranded” thinnings harvested far from industrial centers “Stranded” Thinnings - Key Concerns - Okanogan National Forest - Example - • “Stranded” thinnings are typified by long transportation distance to end-use markets • For long transportation distances, fuel density becomes a key concern and fuel densification will reduce transportation costs Wood Chips Wood Pellets Bio-oil Methanol Low-grade Solid Fuel High-grade Solid Fuel Low-grade Liquid Fuel High-grade Liquid Fuel 350 kg/m3 640 kg/m3 1200 kg/m3 790 kg/m3 • 763,000 acres at risk to wildfire • More than 70% total forested acreage • Urgent thinning need • But densification comes at a cost… • “Stranded” thinnings • No local market for pulp • East of Cascade Crest (east-west barrier) and distant from Spokane Source: Rural Technology Initiative 009,02-07-05,PYR.ppt

  7. Agenda • Thinning of Forests • Bio-fuel Production • Comparison of Alternatives • Conclusions Agenda,02-07-05,PYR

  8. We are interested in optimal size and location for the bio-fuel production facility Bio-fuel Network - Layout - Logging Deck Option 1: Mobile Bio-fuel Production • Highly mobile unit built on semi-trailer • 10 dry tons per day throughput • Spends days to a week at logging deck • 15 year lifetime Option 4: Relocatable Bio-fuel Production • Relocatable facility located at edge of forest in industrial zone (grid electricity available) • 500 dry tons per day throughput • In position for duration of thinning operation (20 year lifetime) Option 2: Transportable Bio-Fuel Production • Modular design readily transported in several semi-trailer containers • 100 dry tons per day throughput • Spends months at collection area • 15 year lifetime Forested Area Logging Road Option 3: Stationary Bio-fuel Production • Stationaryfacility located at edge of forest in industrial zone (grid electricity available) • Sized so single facility consumes entire daily production from forest • Lifetime equal to duration of thinning operation Major Road 007,02-07-05,PYR.ppt

  9. Producing a high-grade solid fuel, like pellets, is primarily a mechanical process Pellet Production - Process Flow - Flue Gas Additives Power 31 kWhr/ton water Power 127 kWhr/dry ton Power 114 kWhr/dry ton Dryer to 10% moisture Grinding to 3 mm Pelletization • Pellets formed by high pressure extrusion of ground wood through die • Pressure raises temperature to over 100oC • Lignin begins to flow and acts as an “adhesive” when cooled • Limited research opportunities • Grinding requirement fixed by standardized pellet size • Mature technology with respect to woody biomass Exhaust Legend Pile Burner Diesel Engine Solid Phase Process Power Gas Phase Problem Mineral Ash Diesel Fuel Primary Path Input or Secondary Path 017,02-07-05,PYR.ppt

  10. Fast pyrolysis produces a low grade bio-fuel, commonly referred to as bio-oil Low-grade Liquid Bio-fuel Production - Overview - • Fast pyrolysis is defined as the thermal decomposition of biomass by rapid heating in the absence of oxygen • Three categories of decomposition products Component Yield (dry mass%) • Condensable Vapors • Light Gas • Char • 70-80% • 10-15% • 10-15% • Condensed vapors are collectively referred to as ‘pyrolysis oil’ or ‘bio-oil’ • Mixture of oxygenated hydrocarbons and water – water is the most common single species • High density liquid fuel (1200 kg/m3) with moderate heating value (16-19 MJ/kg) • Potential applications for industrial heating, power generation, and chemical feedstock for bio-refining • Bio-oil has a number of undesirable characteristics • Low pH (2.5-3) due to organic acids (e.g. acetic acid) • High solids content (1% by mass) – incompatible with downstream applications requiring low solids content (e.g. gas turbines) • High water content (20-30%) – immiscible with hydrocarbon fuels due to polar nature • Over time, chemical composition changes (non-equilibrium) increasing viscosity and water content and decreasing volatility • Fast pyrolysis reactor development driven by char-related issues • Rapid, isothermal heating: lower temperatures favor char formation – substitution effect • Short vapor residence time (1-2 seconds max): char catalyzes cracking of condensable vapors to light gas • Rapid and effective char removal: char fines entrained in bio-oil accelerate ‘aging’ effects 016,02-07-05,PYR.ppt

  11. Production of bio-oil involves relatively few process steps Bio-oil Production - Process Flow - Flue Gas Power 31 kWhr/ton water Power 127 kWhr/dry ton Power 40 kWhr/dry ton Power Dryer to 10% moisture Grinding to 3 mm Fast Pyrolysis Reactor Cyclone Separation Heat Char and Ash Heat Exchanger Exhaust Vapor Quench Dual Fuel Diesel Engine Suspension Combustor Light Gas Process Power Legend Solid Phase Gas Phase Mineral Ash Diesel Fuel 7.5% energy Bio-oil 92.5% energy Liquid Phase Problem Heat Exchanger Storage Waste Heat Primary Path Input or Secondary Path Power 10 kWhr/ton bio-oil Bio-oil 006,02-07-05,PYR.ppt

  12. Most research has been focused on the production of high-grade bio-fuels High Grade Liquid Bio-fuel Production - Overview - • Gasification • Thermal decomposition of biomass in oxygen deficient environment (fuel rich) • Produces a syngas of CO, H2, CO2, and H2O (and N2) Gasification • Dependent Processes • Some clean-up requirements driven by gasification Dirty Syngas Gas Clean-up • Gas Clean-up • Tar • Particulate • Alkali metal vapor Clean Syngas • Largely stand-alone • Developed for use in petrochemical industry • New interest for extraction of “stranded” resources (e.g. natural gas) • Liquid Fuel Synthesis • Optimize CO and H2 concentrations in syngas • Gas to liquid (GTL) process Bio-fuel Synthesis High-grade Liquid Bio-fuel 013,02-07-05,PYR.ppt

  13. For example, gasification and tar removal are closely coupled Biomass Gasification - Gasification and Tar Removal - • Syngas produced by the gasifier must be free of nitrogen • Higher gas volume increases capital cost • Catalysts less effective when syngas diluted by nitrogen • Two gasification options being pursued: Entrained Flow Gasification Indirect Gasification Syngas + Tar Syngas • Wet scrubbing • Removes most tar • Lose tar energy • Waste water stream • Thermodynamic penalty for quench Entrained Flow Gasifier Indirect Gasifier Wood Particles Wood Chips • Catalytic tar cracking • Recover tar energy • Not all tar removed • Short catalyst lifetime Oxygen Air Separation Unit External Heat Steam Air Nitrogen • Re-circulate tars • Removes most tar • Recovers tar energy • Thermodynamic penalty for quench • May produce PAH (carcinogenic) • Very high capital cost at smaller scale • High power consumption 015,02-07-05,PYR.ppt

  14. The devil is in the details. Key issues include gas cleaning, gasifier design, and heat and power integration. Legend Methanol Production - Process Flow - Solid Phase Gas Phase Power Flue Gas Power Power, Heat Liquid Phase Problem Gasification Coarse Sizing Drying Gasifier Primary Path Input or Secondary Path Diesel Fuel Heat Dirty Syngas Aux. Power Generation Pile Burner Power Catalyst Water Power Gas Cleaning Wet Gas Cleaning (100oC) Catalytic Tar Cracking Bag Filtration (350oC) Syngas Compression Multi-cyclone Particulate > 5μm Particulate > 2μm, Alkali Metals Residual Contaminants, Waste Water Clean Syngas Steam Steam Power Power Purge Gas Power Power Generation Heat Methanol Synthesis Methanol Synthesis (260oC) Steam Reformer (890oC) Water-Gas Shift (330oC) CO2 Removal (127oC) Methanol CO2, Acid Gasses 014,02-07-05,PYR.ppt

  15. Clearly, each bio-fuel has advantages and disadvantages Bio-Fuel Comparison - Summary - Pellets Bio-oil Wood Chips Methanol Transportation Cost - - + + + + + Technical Readiness + + + - - - - Product Value - - - + + - Production Cost + + + - - Feedstock Requirement - - - - + N/A Potential for Improvement? N/A - - + + + + How do we quantify these trade-offs? 008,02-07-05,PYR.ppt

  16. Agenda • Thinning of Forests • Bio-fuel Production • Comparison of Alternatives • Conclusions Agenda,02-07-05,PYR

  17. Net thinning cost is an appropriate metric to compare different scenarios Net Thinning Cost - Framework - Net Thinning Cost Revenue Gross Thinning Cost • Bio-fuel • Power • Heat Thinning Transportation Bio-Energy Production • Harvesting activities • Transportation of wood chips or densified bio-fuel • Bio-fuel production • Co-fire or cogeneration 018,02-07-05,PYR.ppt

  18. Net Thinning Cost - Base Case Results - • Transportation Distance • Thinning Yield • Thinning Duration • Annual Acreage Thinned 450 km (~280 miles) 7.5 wet tons/acre 10 years 80,000 acres Transportable Bio-fuel Production Stationary Bio-fuel Production Relocatable Bio-fuel Production Mobile Bio-fuel Production • Wood Pellets • Bio-oil • Methanol • Wood Chip Cogeneration • Co-fire • Pulp Sale $162/wet ton $159/wet ton $214/wet ton $75/wet ton $63/wet ton $71/wet ton $93/wet ton $81/wet ton $126/wet ton $59/wet ton $54/wet ton $59/wet ton $61/wet ton $58/wet ton $74/wet ton 031,02-07-05,PYR.ppt

  19. Disposal preferred beyond this point Net thinning cost for methanol and bio-oil converge Bio-oil preferred over pulp sale For shorter transportation distances, co-fire is preferred by a wide margin Transportation Distance Sensitivity - Base Technology - Two drivers required for round-trip distance Net Thinning Cost ($/wet ton thinnings) Case Assumptions • Thinning Duration: 10 years • Annual Acreage: 80,000 acres Average Transportation Distance (Deck to End-Use) (km) 020,02-07-05,PYR.ppt

  20. Net thinning cost for methanol and bio-oil converge further out Advanced fast pyrolysis for production of bio-oil is cost competitive with pulp sale or cogeneration at shorter distances Transportation Distance Sensitivity - Advanced Technology - Net Thinning Cost ($/wet ton thinnings) Case Assumptions • Thinning Duration: 10 years • Annual Acreage: 80,000 acres Bio-oil preferred over pulp sale much earlier Average Transportation Distance (Deck to End-Use) (km) 021,02-07-05,PYR.ppt

  21. For a given transportation distance, annual acreage thinned, and thinning duration, we can determine the lowest net thinning cost Mapping Bio-energy Options - Methodology - Scenario Results Bio-Energy Technology Map - 500 km Transportation Distance, Base Technology - Facility Bio-Energy Production Net Thinning Cost Mobile Fast Pyrolysis $160/wet ton Thinning Duration (years) Transportable Fast Pyrolysis $83/wet ton 1 3 5 7 9 11 13 15 Stationary Fast Pyrolysis $56/wet ton Relocatable Fast Pyrolysis $62/wet ton 10,000 Mobile Pelletization $163/wet ton 20,000 Transportable Pelletization $95/wet ton 30,000 Stationary Pelletization $61/wet ton 40,000 Annual Acreage Thinned (acres) Relocatable Pelletization $63/wet ton 50,000 Mobile Methanol Synthesis $215/wet ton 60,000 Transportable Methanol Synthesis $129/wet ton 70,000 Stationary Methanol Synthesis $64/wet ton 80,000 Relocatable Methanol Synthesis $83/wet ton 90,000 Co-fire $68/wet ton 100,000 Wood Chip Cogen $82/wet ton Pulp Sale $74/wet ton Repeat analysis for each thinning acreage and duration for multiple transportation distances… Disposal $79/wet ton 005,02-07-05,PYR.ppt

  22. For short transportation distances, bio-fuel production is unattractive Bio-Energy Technology Map - 200 km Transportation, Base Technology - Thinning Duration (years) 1 3 5 7 9 11 13 15 Trends 10,000 • Pulp sale preferred for short durations or small scale operations • Least capitally intensive revenue generating option • Co-fire preferred over wide range of durations and scales Pulp Sale 20,000 30,000 40,000 Annual Acreage Thinned (acres) 50,000 60,000 Co-fire 70,000 80,000 90,000 100,000 001,02-07-05,PYR.ppt

  23. As transportation distance increases, densified bio-fuels become preferred to co-fire and pulp sale Bio-Energy Technology Map - 500 km Transportation, Base Technology - Thinning Duration (years) 1 3 5 7 9 11 13 15 Technology Map Trends 10,000 Pulp Sale Pelletization Stationary • Pulp sale preferred for very short durations and verysmall scale operations • Pelletization preferred for moderate to long durations or moderate to large thinning yields • Least capitally intensive densification process • Methanol synthesis preferred only for very long durations and high yields • Most capitally intensive densification process • Fast pyrolysis preferred for moderate to large yields or moderate to long term operations 20,000 30,000 40,000 Relocatable Annual Acreage Thinned (acres) 50,000 Stat. Relocatable Fast Pyrolysis Stationary 60,000 70,000 80,000 Relocatable 90,000 Methanol Synthesis Stationary Stat. 100,000 002,02-07-05,PYR.ppt

  24. Near term improvements in bio-fuel production technologies are likely to make fast pyrolysis the option of choice for long transportation distances Bio-Energy Technology Map - 500 km Transportation, Advanced Technology - Thinning Duration (years) 1 3 5 7 9 11 13 15 Technology Map Trends 10,000 Pellet Pulp Sale • Pulp sale preferred for very short durations and verysmall scale operations • Fast pyrolysis preferred for most other yields and durations of operations • Smaller, shorter duration thinning favor relocatable production • Larger, longer duration thinning favor stationary production 20,000 30,000 40,000 Relocatable Annual Acreage Thinned (acres) 50,000 60,000 Advanced Fast Pyrolysis Stationary 70,000 80,000 90,000 100,000 003,02-07-05,PYR.ppt

  25. When co-fire is not an option, as might be the case in Washington, advanced fast pyrolysis becomes the lowest cost option even for short transportation distances Bio-Energy Technology Map - 200 km Transportation, Advanced Technology, No Co-fire - Thinning Duration (years) 1 3 5 7 9 11 13 15 Technology Map Trends 10,000 • Co-fire may not be an option in some regions due to a scarcity of coal-fired power plants • Pulp sale preferred for short to moderate durations or small to moderate scale operations • Fast pyrolysis preferred for large or long duration thinning operations 20,000 30,000 Pulp Sale 40,000 Annual Acreage Thinned (acres) 50,000 60,000 70,000 Advanced Fast Pyrolysis Stationary 80,000 90,000 100,000 004,02-07-05,PYR.ppt

  26. Agenda • Thinning of Forests • Bio-fuel Production • Comparison of Alternatives • Conclusions Agenda,02-07-05,PYR

  27. Bio-fuel Production - Conclusions - • Bio-fuel production at a stationary facility outside the forest is preferred over production within the forest • Economics • Lower capital unit costs (scale effect) • Low cost power (grid electricity vs. diesel generators) • Better labor utilization • High availability (better capital utilization) • Practicality • Three-shift operation uncommon within the forest, but is common in industry • Equipment for production of bio-fuels generally designed in expectation of fixed, continuous operation • Transportable and mobile scale facilities should be considered for research, development, and demonstration (RD&D) • Investment cost for a single unit fairly low • Easy to test and stage investment • Once technology proven, scale-up to larger facilities to realize lowest projected costs 022,02-07-05,PYR.ppt

  28. Different options are preferred for different transportation distances Technology Summary - Conclusions - < 400 km Transportation Distance > 400 km Transportation Distance Small Operation Disposal Disposal Pulp Sale Pellets Moderate Operation Advanced Fast Pyrolysis Co-fire Fast Pyrolysis Large Operation Methanol 030,02-07-05,PYR.ppt

  29. This analysis allows us to answer a few key questions Bio-Energy from Thinnings - Conclusions - • Does the conversion of thinnings to bio-energy make economic sense? • Yes. But, with current technology, only when the transportation distance to end-use exceeds 400 km. • Bio-energy will not pay for thinning. But the economics are stronger than for disposal in almost all cases • Which bio-energy technologies are most promising? • Co-fire with coal for transportation distances less than 400 km • Fast pyrolysis for bio-oil where transportation distances are longer • Where are non-energy options preferable? • Pulp sale for short durations and low yields where transportation distances are less than 600 km • Disposal for very short durations and low yields where transportation distances are longer 024,02-07-05,PYR.ppt

  30. Next Steps • Forestry • Estimated probabilities for various acreage yields and durations • Economics of forest products • Model • Rail transportation and hybrid rail-truck transportation networks • Other bio-fuel production technologies • Solid fuel briquettes • Fischer-Tropsch fuels • Other bio-fuel end-uses • Close-coupled gasification-combustion applications • Biomass Gasification Combined Cycle (BiGCC) • Improved visualization of results • Research • Methods for improved bio-oil combustion • Large feedstock fast pyrolysis 025,02-07-05,PYR.ppt

  31. Questions? 028,02-07-05,PYR.ppt

  32. Net thinning costs are lowest for stationary bio-fuel production. The small penalty for transporting chips out of the forest is outweighed by large reductions in bio-fuel production cost. Bio-oil Production - Cost Detail - Mobile $159/wet ton thinnings Transportable $81/wet ton thinnings Stationary $54/wet ton thinnings Transportation $8 • Bio-oil $8 Transportation $12 • Wood Chips $2 • Bio-oil $101 Net Thinning Cost ($/ton wet thinnings) Transportation $12 • Wood Chips $7 • Bio-oil $6 Production $141 Production $52 Production $27 Harvest $40 Harvest $40 Harvest $40 Note: Revenue increase due to higher yields of bio-oil for stationary and transportable production Revenue $19 Revenue $23 Revenue $26 1Higher cost due to higher bio-oil yield for transportable conversion 019,02-07-05,PYR.ppt

  33. An interesting extension of this analysis is to forecast costs for technical advances and the benefit of learning scale Advanced Technology Case - Assumptions - Fast Pyrolysis Methanol Synthesis Base Case Advanced Case Base Case Advanced Case • 3 mm chip size • Hammer-milling required • 6 mm chip size • Coarse sizing only • Wet, cold gas cleaning • Hot, dry gas cleaning Technology • 1st unit costs • 10th unit costs • Justified by successful first generation demonstrations • 1st unit costs • 1st unit costs • No successful commercial demonstration Learning Scale Substantial cost reduction Modest cost reduction, Enhanced practicality These scenarios represent advanced, but realistically near-term process evolutions 027,02-07-05,PYR.ppt

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