Small-scale District Heating based on Biomass
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Transcript of Small-scale District Heating based on Biomass
Small-scale District Heating Small-scale District Heating based on Biomassbased on Biomass
Joakim LundgrenJoakim Lundgren
Division of Energy EngineeringDivision of Energy Engineering
Luleå University of TechnologyLuleå University of Technology
BackgroundBackground Nuclear power phase outNuclear power phase out A large amount of electricity is today A large amount of electricity is today
used for heating purposesused for heating purposes Important to reduce the electricity Important to reduce the electricity
demanddemand One measure is to convert to district One measure is to convert to district
heating – an activity in progress heating – an activity in progress
BackgroundBackground
Biomass based district heating for larger Biomass based district heating for larger communities is well established in Swedencommunities is well established in Sweden
Increasing taxes on fuel oil and Increasing taxes on fuel oil and distribution network developments have distribution network developments have made DH interesting also for smaller made DH interesting also for smaller communitiescommunities
Space for at least 10 GW new installed Space for at least 10 GW new installed thermal power in small biomass fired DH thermal power in small biomass fired DH networksnetworks
ProblemsProblems
Studies show that boilers (0.5-10 MW) Studies show that boilers (0.5-10 MW) emits large amounts of hazardous emits large amounts of hazardous products (CO, THC, PAH, VOC) during products (CO, THC, PAH, VOC) during low and varying heat loadslow and varying heat loads
EconomyEconomy
EU project 1998-2001EU project 1998-2001
Develop a boiler concept suitable for Develop a boiler concept suitable for small DH systemssmall DH systems Broad thermal output span (10-100%)Broad thermal output span (10-100%) High fuel moisture contentHigh fuel moisture content Manage heat load fluctuationsManage heat load fluctuations Low emissions of harmful products in Low emissions of harmful products in
the complete thermal output spanthe complete thermal output span
ApplicationsApplications
Public buildingsPublic buildings Small industries and shopping centersSmall industries and shopping centers Small DH networks in villages Small DH networks in villages
……in purpose to change from fossil fuels in purpose to change from fossil fuels in existing boilers or to convert from in existing boilers or to convert from electricityelectricity
Layout of the research plantLayout of the research plant
Cyclones
Furnace Fuel storeFuel
containers
Boiler
Heat store Chimney
To DH network
Module 2
Module 1
Primary combustion Primary combustion chamberchamberGases to the sec. Gases to the sec. zonezone
Fuel feedingFuel feeding
•Partitioned combustion chamberPartitioned combustion chamber
•Drying zoneDrying zone
Secondary zoneSecondary zone
To the boilerTo the boiler
•High gas temperaturesHigh gas temperatures
•Good mixing with combustible Good mixing with combustible gases and secondary airgases and secondary air
•Designed by using CFDDesigned by using CFD
Experimental resultsExperimental results
0
20
40
60
80
100
120
50 60 150 175 200 250 350 500
Thermal output (kW)
CO
and
NO
x (m
g/M
J)
0
0,5
1
1,5
2
2,5
TH
C (m
g/M
J) a
nd e
xces
s ai
r ra
tio
CO NOx THC Excess air
ConclusionsConclusions
Very low emissions of hazardous Very low emissions of hazardous productsproducts
Can manage fuel moisture contents Can manage fuel moisture contents up to 58%up to 58%
Can handle heat load variations with Can handle heat load variations with kept low emissionskept low emissions
Great potential. 10 GW means Great potential. 10 GW means approximately 2000 new boilersapproximately 2000 new boilers
New projectsNew projects Replacing an oil fired boiler in a school Replacing an oil fired boiler in a school
building (Demonstration unit)building (Demonstration unit) BIO-SOL. Biomass based DH in BIO-SOL. Biomass based DH in
combination with solar energycombination with solar energy Combustion of horse manureCombustion of horse manure
BIO-SOLBIO-SOLConventional systemConventional system
BIO-SOLBIO-SOL
ProblemProblem Large heat losses during summer Large heat losses during summer
time, calculated as percentage of the time, calculated as percentage of the generated heat generated heat
Our ideaOur idea Let the customers produce their own Let the customers produce their own
heat during summerheat during summer
Distributed solar collectors and Distributed solar collectors and heat storesheat stores
Combustion of horse Combustion of horse manuremanure
Large costs for depositing waste Large costs for depositing waste materials, up to €100 per tonmaterials, up to €100 per ton
One horse produces 10 tonnes per yearOne horse produces 10 tonnes per year 300 000 horses in Sweden, resulting in 300 000 horses in Sweden, resulting in
a total amount of 3 million tonnes a total amount of 3 million tonnes annuallyannually
Year 2005, there will be a prohibition Year 2005, there will be a prohibition for depositing organic materialsfor depositing organic materials
Very large economical benefits for Very large economical benefits for stable- and trotting course ownersstable- and trotting course owners
Decreasing the demand for fuel oil Decreasing the demand for fuel oil and electricity and electricity
The only condition is that the The only condition is that the combustion process must be combustion process must be environmentally friendly environmentally friendly
Combustion of horse Combustion of horse manuremanure
Experimental resultsExperimental results
0
50
100
150
200
250
300
350
400
Manure Wood-chips
Em
issi
on
s (m
g/n
m3)
CO
NOx