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

OUTLINEOUTLINEBackground Distributed BioPower systemsHow do we compare systems? Efficiency comparison– Gasification– Bio-Oil– Small steam– ORC– ERC

50% MC CHP conversion 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.org

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?

Distributed BioPower Distributed BioPower ApplicationsApplicationsforestry wasteOSB plantsdiesel communitiesgreenhouses forest thinning – fire control

agricultural wastes animal wastes municipal wastes

CHP Sawmill ExampleCHP Sawmill Example

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)

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 – ignore parasitic power for bio-oil & gasifier– mass and energy balances

Account for every step in conversionExclude use of specialized materials

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

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

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)

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

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

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

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

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

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

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

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

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% 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%

1

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)

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

Natural Resources CanadaCommission for Environmental CooperationNational Research CouncilManitoba Hydro: Chair in Alternative Energy

ACKNOWLEDGEMENTACKNOWLEDGEMENT