distributed heat and power biomass systemshome.cc.umanitoba.ca/~bibeauel/research/papers/2004... ·...
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Distributed Heat and Power Distributed Heat and Power
Biomass SystemsBiomass Systems
Denver, Colorado USAAugust 29-September 3, 2004
Dr. Eric BibeauDr. Eric BibeauMechanical & Industrial Engineering DeptMechanical & Industrial Engineering Dept
Doug SmithDoug SmithInnovative Dynamics Ltd., Vancouver BCInnovative Dynamics Ltd., Vancouver BC
Martin TampierMartin TampierEnvirochem Services Inc., Vancouver BCEnvirochem Services Inc., Vancouver BC
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OUTLINEOUTLINEBackground Distributed BioPower systemsHow do we compare systems? Efficiency comparison– Gasification– Bio-Oil– Small steam– ORC– ERC
50% MC CHP conversion chart Conclusions
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Distributed BioPower BackgroundDistributed BioPower Background
Biomass Life Cycle Analysis (LCA)– Identifying environmentally preferable
uses for biomass resources–Life-cycle emission reduction benefits of
selected feedstock-to product treads–Reports CEC website
Commission for Environmental Cooperationwww.cec.org
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Distributed BioPower BackgroundDistributed BioPower BackgroundBarriers to distributed BioPower– need large scale capital cost + low O&M costs– need CHP economics
Low Canadian power rates– Residential/Commercial/Industrial: 4.3 / 3.6 / 2.5 cents US
Industrial users– convert waste to power incentive
Biomass: poor fuel + distributed– transportation cost limitation – biopower considered to be 20 MW and up
Decentralized power– when will it come?
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Distributed BioPower Distributed BioPower ApplicationsApplicationsforestry wasteOSB plantsdiesel communitiesgreenhouses forest thinning – fire control
agricultural wastes animal wastes municipal wastes
CHP Sawmill ExampleCHP Sawmill Example
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How Does One Compare How Does One Compare Distributed Power Systems?Distributed Power Systems?
Common feedstock?Overall Conversion Efficiency?Account for small scale?Do this for–– BioBio--oiloil–– GasifierGasifier–– Steam cycle (no CHP)Steam cycle (no CHP)–– Organic Rankine Cycle (ORC)Organic Rankine Cycle (ORC)–– Entropic Rankine Cycle (ERC)Entropic Rankine Cycle (ERC)
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FEEDSTOCKFEEDSTOCK
Volume
(dry) (wet) FractionCarbon, C 50.0% 25.0% 29.50%
Hydrogen, H2 6.0% 3.0% 21.20%Oxygen, O2 42.0% 21.0% 9.30%
Nitrogen, N2 2.0% 1.0% 0.60%Water, H2O 0.0% 50.0% 39.40%
Feed Analysis
Mass Fraction
Biomass feedstock = natures solar energy storage system
HHV = 20.5 MJ/BDkgfuel & 50% MC
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Modeling ApproachModeling ApproachRealistic systems for small size– limit cycle improvement opportunities
cost effective for technology for small size– limit external heat/power to system– adapt component efficiencies to scale
Model system as if building system today– design actual conversion energy system – ignore parasitic power for bio-oil & gasifier– mass and energy balances
Account for every step in conversionExclude use of specialized materials
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BioBio--OilOilLiquid: condense pyrolysis gases – add heat; no oxygen – organic vapor + pyrolysis gases + charcoal
Advantages for distributed BioPower– increases HHV – lessens cost of energy transport – produces “value-added” chemicals
Disadvantages for distributed BioPower– energy left in the char– fuel: dry + sized
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BIOBIO--OILOIL
Rotating Cone (fast pyrolysis)
Travelling Bed (fast pyrolysis)
Bubbling Bed (fast pyrolysis)
Slow pyrolysis
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BioBio--OilOilJF Bioenergy ROI Dynamotive Ensyn
Bio-oil (% by weight) 25% 60% 60% – 75% 60% – 80%Non-cond. gas (% by weight) 42% 15% 10% – 20% 8% – 17%Char (% by weight) 33% 25% 15% – 25% 12% – 28%Fuel feed moisture Not published
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BioBio--oil Overall Energy Balanceoil Overall Energy Balance
Biomass Feed 50% moisture
Drying/Sizing to 10% / 2 mm Pyrolysis
21.5% energy loss 32% energy
Char 45.6%
energy loss
Engine/ Generator
6.4% Electricity
60% energy Bio-oil
8% energy loss
18.5%
3%
3%
5%
N2 Sand
Electricity: 363 kWhr/BDtonne
Pyrolysis heat: non-condensable gas + some char (no NG)Pyrolysis power: 220 – 450 kWhr/BDtonne (335 or 5%)Engine efficiency: 28% (lower HHV fuel; larger engine; water in oil lowers LHV)Other parasitic power neglected (conservative)Limited useable cogeneration heat
PowerPower
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Gasifier Gasifier -- Producer GasProducer GasSub-stoichiometric combustion – syngas: CO, CH4, H2, H2O– contains particles, ash, tars
Advantages for distributed BioPower– engines and turbines (Brayton Cycle)– less particulate emission
Disadvantages for distributed BioPower– flue gas cleaning– cool syngas – fuel: dry + sized – quality of gas fluctuates with feed
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GasifierGasifier
Assume require 25% MC and no sizing requirements (conservative)Ignore parasitic loads: dryer, gas cooler, gas cleaning, tar removal, fans (conservative)Heat to dry fuel comes from process (3.8 MJ/BDkgfuel)100% conversion of char to gas (conservative)HHV of syngas = 5.5 MJ/m3 dry gas
Syngas Vol Dry vol Dry wgtfraction fraction kg/kgfeed
CO 0.1907 0.2994 0.461CO2 0.0365 0.0573 0.139CH4 0.0143 0.0224 0.02H2O 0.363 0 0
H2 0.1043 0.1638 0.018N2 0.2911 0.457 0.703
5.5 MJ/m3 dry gasHHV (dry gas)
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Gasification Overall Energy BalanceGasification Overall Energy Balance
Biomass Feed 50% moisture
Drying to 25%
40% energy Producer Gas
7.75% Electricity
Engine/ Generator Gasification
15%
15% energy loss
60% energy loss
17.25% energy loss
Electricity: 440 kWhr/BDtonne
Low HHV of gas affects efficiency of engineAssume ICE operates at 75% of design efficiency15% heat from producer gas dries fuelNo heat lost across gasifier boundaryLimited useable cogeneration heat
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Small Steam CycleSmall Steam Cycle(no CHP)(no CHP)
Steam Rankine Cycle– common approach – water boiled, superheated, expanded, condensed and
compressed
Advantages distributed BioPower– well known technology – commercially available equipment
Disadvantages distributed BioPower – costly in small power sizes – large equipment and particulate removal from flue gas
Deaerator
BoilerTube Bank
& Wet Wall
Super Heater
Economizer
Attemporator
Feed Pump
Condenser
Ejector
8%steam
makeup
Turbine
1
23
4
67
8
9
2% blowdown
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Small Steam Overall Energy BalanceSmall Steam Overall Energy Balance
Biomass Feed 50% moisture Heat Recovery Steam Cycle
9.9% Electricity
40.5% energy loss
49.6% energy loss
Electricity: 563 kWhr/BDtonne
Limit steam to 4.6 MPa and 400oC (keep material costs low)Use available turbines for that size: low efficiency (50%)No economizer4% parasitic loadFlue gas temperature limited to 1000oC for NOxAll major heat losses and parasitic loads accounted
4% power
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ORCORCAdvantages distributed BioPower– smaller condenser and turbine as high
turbine exhaust pressure– higher conversion efficiency– no chemical treatment or vacuum– no government certified operators– CHP – Dry air cooling can reject unused heat
Disadvantage for distributed BioPower– organic fluid ¼ of water enthalpy– binary system– systems are expensive – particulate removal from flue gas
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ORCORC
Biomass Feed50% moisture Turboden CycleHeat Recovery
80°C liquidcogeneration
10.2% Electricity
40.1%energy loss
49.7%energy loss
Electricity: 580 kWhr/BDtonneHeat: 2713 kWhr/BDtonne
Flue gas temperature limited to 1000oC for NOxCool flue gas down to 310oCCHP heat at 80oCAll major heat losses and parasitic loads accounted
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ERCERCAdvantages for small BioPower– pre-vaporized non-steam fluid – small turbine and equipment – no chemical treatment, de-aeration or vacuums – no government certified operators– ideal for CHP: 90°C to 115°C – dry air cooling can reject unused heat
Disadvantages for small BioPower– restricted to small power sizes (< 5 MW)– system has not been demonstrated commercially– special design of turbine– particulate removal from flue gas
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ERCERC
Biomass Feed 50% moisture Entropic CycleHeat Recovery
90°C liquidcogeneration
12.0% Electricity
56.2%energy loss
31.8%energy loss
Electricity: 682 kWhr/BDtonneHeat: 3066 kWhr/BDtonne
Flue gas temperature limited to 1000oC for NOx
Cool flue gas down to 215°CCHP heat at 90oC
Fluid limited to 400°CAll major heat losses and parasitic loads accounted
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NonNon--Steam Base SystemsSteam Base SystemsORC & ERCORC & ERC
Thermal Oil Heat Transfer
TURBODEN srl
synthetic oil ORC
Conversion
1000°C 310°C
250°C 300°C
60°C
80°C Liquid Coolant
Air heat dump
17%
Input Heater 59.9% recovery
Entropic Fluid Heat
Transfer
ENTROPICpower cycleConversion
1000°C 215°C
170°C400°C
60°C
90°C Liquid Coolant
Air heat dump
17.6%
Input Heater 68.2% recovery
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Distributed BioPowerDistributed BioPowerCHP Conversion ChartCHP Conversion Chart
Note: Results are for 50% moistures content
Bio-oil GasificationSyngas
AirBrayton
Large Steam
Overall Power Efficiency 6.6% 7.8% 7.4% 15.9%Electricity (kWhr/Bdtonne) 363 440 420 903Heat (kWhr/Bdtonne) - - - -Overall Cogen Efficiency 6.4% 7.8% 7.4% 15.9%
SmallSteam
SmallSteam CHP
OrganicRankine Entropic
Overall Power Efficiency 9.9% 5.7% 10.2% 12.0%Electricity (kWhr/Bdtonne) 563 324 580 682Heat (kWhr/Bdtonne) - 2,936 2,713 3,066Overall Cogen Efficiency 9.9% 53.9% 54.5% 67.5%
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Distributed BioPowerDistributed BioPowerCHP Conversion ChartCHP Conversion Chart
Note: Results are for 50% moistures content
$0.038 per kWhr$0.014 per kWhr
USDPower (85% use) Heat (40% use) Total
Bio-Oil $11.8 n/a $11.8Gasification $14.3 n/a $14.3Air Brayton $13.6 n/a $13.6
Large Steam (simple) $29.3 n/a $29.3Small Steam $18.3 n/a $18.3
Small Steam CHP $10.5 $16.1 $26.6ORC $18.8 $14.9 $33.7ERC $22.1 $16.9 $39.0
Revenue (per BDTon)
Electrical Power (USD)Natural gas (USD)
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ConclusionConclusionConversion: losses at many points Comparison: energy captured from original fuel– moisture content – scaling effect
Technologies: drying and sizing – disadvantage for small distributed systems
High parasitic loads at further disadvantage Power and heat produced for base fuel
30662713NoneNoneNoneUseful heat (kWhr/Bdtonne)
682580563440363Electrical (kWhr/Bdtonne)ERCORCSmall steamGasificationBio-oilSystem
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Natural Resources CanadaCommission for Environmental CooperationNational Research CouncilManitoba Hydro: Chair in Alternative Energy
ACKNOWLEDGEMENTACKNOWLEDGEMENT