Bioenergy Greenhouse Gas Balances for Distributed...
Transcript of Bioenergy Greenhouse Gas Balances for Distributed...
-
Bioenergy Greenhouse Gas Bioenergy Greenhouse Gas Balances for Distributed PowerBalances for Distributed Power
Bioenergy and Northern Communities in Canada Workshop, Saskatoon, Nov 16-17, 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
-
Arctic Climate Impact Assessment ReportArctic Climate Impact Assessment Report
““Arctic will lose 50Arctic will lose 50--60 per cent of its ice distribution by 2100”60 per cent of its ice distribution by 2100”
“one model predicts that the North Pole in summer will be comple“one model predicts that the North Pole in summer will be completely tely iceice--free by 2070”free by 2070”
“Projections made by the Intergovernmental Panel on Climate Chan“Projections made by the Intergovernmental Panel on Climate Change ge estimates that if global greenhouse gas emissions double their pestimates that if global greenhouse gas emissions double their prere--industrial levels, melting ice will raise sea levels between 10 industrial levels, melting ice will raise sea levels between 10 and 90 cm and 90 cm in this century”in this century”
Human Activity Affects Dynamic SystemAdds 30 Billion tonnes of new CO2 per year
-
OUTLINEOUTLINEDistributed BioPower systems backgroundHow do we calculate greenhouse gas displacements – distributed systems under development– efficiency: scaling effect/cost constraints
Efficiency calculations: How?50% MC CHP conversion chart 50% MC greenhouse gas chart Conclusions
-
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.orgAuthors: Tampier, Smith, Bibeau, Beauchemin
-
Distributed BioPower BackgroundDistributed BioPower BackgroundBarriers to distributed BioPower– need low 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: low HHV fuel + distributed– transportation cost limitation– biopower considered to be 20 MW and up
Decentralized power– when will it come?
-
Distributed BioPower Distributed BioPower ApplicationsApplicationsApplications
• forestry waste• OSB plants• diesel communities• greenhouses • forest thinning• bugwood• wildfire control• agricultural wastes • animal wastes • municipal wastes
Bio-Energy Drivers
• GHG• Energy supply• Innovation• Rural development• Air quality
-
How Does One Calculate GHG for How Does One Calculate GHG for Distributed Power Systems?Distributed Power Systems?
Effect of feedstock?Effect of Conversion Efficiency?Accounting for small scale?Compare conversion technology?Factors affecting actual implementation and getting actual GHG displacement
Example:
New Hampshire experience studying bio-oil• What was learned?
• What information was missing?
-
Technologies Used to Calculate GHG Technologies Used to Calculate GHG Displacement for Distributed SystemsDisplacement for Distributed Systems
BioBio--oil (fast and slow pyrolysis)oil (fast and slow pyrolysis)Gasifier (syngas)Gasifier (syngas)Steam with no CHPSteam with no CHPSteam with CHPSteam with CHPOrganic Rankine Cycle (ORC)Organic Rankine Cycle (ORC)Entropic Hybrid Cycle (Entropic Hybrid Cycle (EHCEHC))Air Brayton CycleAir Brayton CycleLarge steam (for reference)Large steam (for reference)
What are the GHG emissions displacements opportunities for each technology?
-
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
-
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 – some components of parasitic power for bio-oil
& gasifier not accounted for– mass and energy balances
Account for every step in conversionExclude use of specialized materials
-
11-- 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
-
BIOBIO--OILOIL
Rotating Cone (fast pyrolysis)
Travelling Bed (fast pyrolysis)
Bubbling Bed (fast pyrolysis)
Slow pyrolysis
-
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
-
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
-
2 2 -- 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– syngas gas cleaning– cool syngas – fuel: dry + sized – quality of gas fluctuates with feed
-
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 (16% of natural 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)
-
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
-
33--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– high operator qualification
Superheater
Economizer
Boiler
Feed Pump
Deaerator
Attemporator
Condenser
8% steam
Ejector
Turbine
2% blowdown makeup
10
9
76
4
3
2
1
8
-
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
-
4 4 -- Small Steam CycleSmall Steam Cycle(with CHP)(with CHP)
CHP– limit pressure drop across turbine
use back pressure turbine rather than condensing turbine
– steam from turbine contains useful heat
Advantages distributed BioPower– CHP economics – reduces volumetric flow– heat + power increases overall efficiency of system
Disadvantages distributed BioPower – reduced power production– high operator qualification
Superheater
Economizer
Boiler
Feed Pump
Deaerator
Attemporator
Turbine
2%blowdown
Condensate returnand makeup
10
9
6
4
3
18
7
Co-generation process
5
-
Small Steam CHP Overall Energy BalanceSmall Steam CHP Overall Energy Balance
Electricity: 324 kWhr/BDtonne Heat: 2936 kWhr/BDtonne
Limit steam to 4.6 MPa and 400oC (keep material costs low)Could use economizer to pre-heat combustion airMany ways to improve efficiency
Biomass Feed50% moisture
Steam Cycle5.7%
Electricity
Heat Recovery
115°C steamcogeneration
40.5%energy loss
53.8%energy loss
-
5 5 -- ORC ORC (Organic Rankine Cycle)(Organic Rankine Cycle)Advantages 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
-
ORCORC
Biomass Feed50% moisture Turboden CycleHeat Recovery
80°C liquidcogeneration
10.2% Electricity
40.1%energy loss
49.7%energy loss
Electricity: 580 kWhr/BDtonne Heat: 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
-
EHCEHC (Entropic Hybrid Cycle)(Entropic Hybrid Cycle)Advantages for small BioPower– vapour heater - no boiler – small turbine and equipment – no chemical treatment, de-aeration or vacuums – no registered steam 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
-
EHCEHC
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
-
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
Cycle efficiency Cycle efficiency
-
Air Brayton CycleAir Brayton CycleAdvantages – simple– use air at relatively low pressures– off the shelf turbine/compressor– many ways to optimize cycle
Disadvantages – increased cycle pressures limits
heat recovery from indirect heat exchanger
– air specific volume large– significant compression work– air has low enthalpy
650°C 315°C
367 kPa258 °C
111 kPa315 °C 336 kPa
483 °C
377 kPa127 °C
13.1% cycle eff. 58.3%
cycle energy
108 kPa185 °C
101 kPa15.6 °C
Air Heater
7.4% overall eff.
Compressor Turbine / Expander
Recuperator
combustion air
56.7% recovery
-
Air Brayton CycleAir Brayton Cycle
Electricity: 420 kWhr/BDtonne
Flue gas temperature inlet to heater limited to 650oC for material requirementsRecuperator with single-stage turbineNo preheat of combustion air (34% increase in efficiency)Tube metal temperatures limited to 565oCTurbine thermal efficiency 85%
Biomass Feed50% moisture Heat Recovery Brayton Cycle
7.4% Electricity
34.4%energy loss
14.9%58.2%energy loss
Biomass Feed50% moisture Heat Recovery Brayton Cycle
7.4% Electricity
34.4%energy loss
14.9%58.2%energy loss
-
LARGE STEAM BIOMASS LARGE STEAM BIOMASS
Largest independent biomass power plant in
North America
Quoted overall efficiency 29%• note: efficiency may be over estimated• MC less than 50%
-
1
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% 25.0%Electricity (kWhr/Bdtonne) 363 440 420 1420Heat (kWhr/Bdtonne) - - - -Overall Cogen Efficiency 6.4% 7.8% 7.4% 25.0%
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%
-
GHG DisplacementsGHG DisplacementsBiomass Emissions– CO2 neutral– CH4
active use can be better or worse than natural decay– Paticulate
can be addressed– Sulfur
biomass (except for MSW) has low S– NOx
important in collection and final combustion
-
Fossil Fuel Used: COFossil Fuel Used: CO22 CostCostWaste biomass application (residues)– often no fuel usage attributed to biomass– transportation (wood chips 35% MC)
0.0249 kgfuel/km/BDtonne 3.2 kgCO2 released for 40 km
– from emissions point transportation of biomassvery positive on CO2 displaced (< 1% CO2 cost per 100 km)economic limitation ($65/BDtonne for 125 km)
-
GHG DisplacementGHG DisplacementElectricity (kWe- hr)– displace electricity from various sources– look at (1) location, (2) average electricity
on the grid, (3) additional load– favorable to displace fossil fuels generation
only
(tonnes/MWh) (tonnes/TJ) (tonnes/MWh) (tonnes/TJ)Newfoundland and Labrador 0.02 6.2 0.000 0.0Prince Edward Island 0.50 137.9 0.807 224.2Nova Scotia 0.74 204.5 0.542 150.5New Brunswick 0.50 137.9 0.807 224.2Quebec 0.01 2.5 0.000 0.0Ontario 0.23 65.2 0.542 150.5Manitoba 0.03 8.2 0.000 0.0Saskatchewan 0.83 231.7 0.542 150.5Alberta 0.91 252.1 0.542 150.5British Columbia 0.03 7.4 0.000 0.0Territories 0.35 98.5 0.909 252.5Marginal Canadian Emission Factor 0.22 61.3 0.426 118.4
CO2, CH4, N2O
Electricity Emissions Average Marginal Provincial Emission
CO2
Example:
Manitoba versus Wha Ti diesel
remote community
-
GHG DisplacementGHG DisplacementHeat (kWth- hr)– integrated areas
displace oil, natural gas, electricity
– non-integrated areadisplace oil
Northern Community: special case– off-grid power from transported diesel– off grid heat from transported oil– very favorable to CHP
ORC, EHC, and small steam CHP
-
GHG Displacement by BiomassGHG Displacement by BiomassScenario Description Emissions
per kWe-hrTypical Regions
1 Low carbon intensity power generation: 90% of nuclear or large hydropower; 10% natural gas
CO2: 52 g Québec, British Columbia, Manitoba; France; Norway; Sweden
2 Moderate carbon intensity power mix:65% nuclear/large hydro, 25% coal, 10% natural gas
CO2: 288 g Canadian average; Ontario; Atlantic Canada; Austria; Belgium
3 High coal/oil content in power production (50%); nuclear/large hydro: 25%; natural gas: 25%
CO2: 588 g United States average, Denmark; Germany; Mexico; Spain; U.K.
4 Very high coal/oil content 75%, nuclear/large hydro 15%, natural gas 10%
CO2: 761 g Alberta, Saskatchewan, central U.S.; Greece; Ireland; Netherlands
-900-800-700-600-500-400-300-200-100
0
CHP SYSTEMSSmall Steam Turboden Entropic
GH
G E
MIS
SIO
N
(kgC
O2/
BD
tonn
e)
Heating OilNatural Gas
Power
Heat
-
Comparison of Biomass OptionsComparison of Biomass Options(Distributed and 50% MC)(Distributed and 50% MC)
-1400
-1200
-1000
-800-600
-400
-200
0
EMISSION REDUCTIONS for CHP SYSTEMS
GH
G E
MIS
SIO
N(k
g CO
2/BD
tonn
e)
Scenario 1Scenario 2Scenario 3Scenario 4
LargeSteamPow er
SmallSteamPow er
BraytonCycle
Pow er
Bio-oilConver.Pow er
Gasif.Conver.Pow er
SmallSteam
CHP
TurbodenCycleCHP
EntropicCycleCHP
Displacing oil for heat
-
Bioenergy in Northern Communities
2 MWe Community Subsidized Power System BioPower SystemPower (2 MWe) tonne CO2 0 tonne CO2Heat (10 MWth) tonne CO2 0 tonne CO2Total tonne CO2 0 tonne CO2
115532305534,608
Power: Diesel Fuel Turbion™ CHPNorthern Community
Heat: Oil Biomass (local or pellets)2 BD tonne/MWe-hr
Power
Heat
~233 liters/ MWe-hr~2.83 Kg CO2/ liter
~93 liters/ MWth-hr~2.83 Kg CO2/ liter
~1 MWe-hr~No GHG
~5 MWth-hr~No GHG
BioPower SystemSubsidized Power System
(Biomass district heat already installed)
CHOICES?
-
$0.060 per kWhr$0.025 per kWhr
Canadian DollarsPower (85% use) Heat (40% use) Total
Bio-oil $19 $19Gasification Syngas $22 $22Air Brayton $21 $21Large Steam $72 $72Small Steam $29 $29Small Steam CHP $17 $29 $46Organic Rankine $30 $27 $57Entropic Hybrid $35 $31 $65
Revenue per BDTon Biomass
Electical PowerNartural Gas
*Revenue for distributed biopower systems using 50% MC biomass
1
Distributed BioPowerDistributed BioPowerCHP Revenue Chart CHP Revenue Chart
-
Technical complexity
25%
-
Manitoba Hydro: Chair in Alternative Energy
Natural Resources Canada
Commission for Environmental Cooperation
National Research Council
ACKNOWLEDGEMENTACKNOWLEDGEMENT