electrostatic precipitators for small-scale wood...
TRANSCRIPT
Technologie- und Förderzentrumim Kompetenzzentrum für Nachwachsende Rohstoffe
P 11 B Ha 001
HartmannFolie 1
Hans Hartmann, Peter Turowski, Susanne Kiener
Technologie- und Förderzentrum im Kompetenzzentrum
für Nachwachsende Rohstoffe (TFZ), Straubing
Electrostatic precipitators for small-scale wood
combustion systems –
Results from lab- and field tests
IEA Task32-Workshop:
“Fine particulate emissions from small-scale biomass furnaces“
Central European Biomass Conference (CEBC), 26.-28.January 2011 in Graz
Technologie- und Förderzentrumim Kompetenzzentrum für Nachwachsende Rohstoffe
P 11 B Ha 001
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Structure
• Overview on small-scale particle separators
• Field test with 3 ESP-types
• Results from test stand trials (4 ESP‘s)
• Summary and conclusions
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P 11 B Ha 001
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Overview on particle separator types for residential applications
Principle Advantage Disadvantage
Electrostatic
precipitator (ESP)
low pressure drop,
low cost
problems with organic
particles
Filtering separators
(e.g. baghouse filters)
good separation effect high pressure drop,
high technical efforts
Cyclone separators low cost low effect on fine particles
Scrubber flue gas condensation possible high technical efforts
medium separation effect
Flue gas condenation additional heat gain low separation effect
Catalyst effect on gases,
lower Corg load on particles
very low separation effect
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P 11 B Ha 001
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Configuration of ESP‘s
Chimney-top separators
Separators for flue gas tube integration
(living rooms)
Separators for central heating boilers
ESP-chimney systems
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Chimney-top ESP (1): Applied Plasma Physics (Norway)
Type: APP Residential ESP
Cleaning/maintennance from chimney top
effective length : ca. 1 m
High voltage; max. 33 kV
No active mechanical removal of PM deposits
Status: development
Photos:TFZ
part of precipitator
inside the chimney
high voltage electrode
part of precipitator
above the chimney
outlet
high voltage supply line
Gra
ph: A
PP
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Chimney-top ESP (2): OekoTube (by OekoSolve, Liechtenstein)
Type: Oekotube
no active removal of deposits
max 70 kW heat power output
Status: market available (only Switzerland)
Photos / Image: Oekosolve
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Weather protection
Isolation
Vibrator for
cleaning
Electronics
Mounting plate
High voltage
electrode
Ionisation zone
Inner tube
(springs)
Precipitation
zone
Chimney-top ESP (3): Ruff-Kat GmbH, Holzkirchen
Type: Ruff-Kat
Chimney mounted
Voltage: 20 kV
Mechanical removal of deposits (vibration)
Length: ca. 1 m above chimney opening
Status: Certified, field test
Separation surface (inner walls)
cleaned uncleaned
Photos / Image: Ruff-Kat
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Boiler attached ESP (1): Spanner SFF (by Fa. Spanner Re²)
Types: Spanner SFF 20 / SFF50 / SFF100
Mounted beside a boiler
Voltage: 15 kV
Mechanical removal of deposits (vibration)
With purge air cleaning of electrodes
Pressure drop: 40 pa
Status: Field tests
raw gas
clean gas
electrode
absorber
pipes
particle
container
pipe -cleaning
(vibration)4 depositing pipes with electrode casing
purge air cylinder
purge air cylinder
Werkbild : SpannerPhotos: TFZ
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Boiler attached ESP (2): Carola – Separator (by KIT, Karlsruhe)
Type: CAROLA (Develpment: Karlsruhe Institut of Technology)
Mounted beside a boiler
Mechanical removal of deposits (rot. brush, 1 min/h)
Pressure drop: 10 pa
Voltage 16-18 kV
Tested with up to 30 kW
Status: development
Images: KIT
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Boiler attached ESP (3): AL-Top (by Schräder, Kamen)
Type: AL-Top,
ESP with infill of wetted metal
shavings as absobing surface
Mounted beside a boiler
Status: development
clean
gas
metal shavings infill
(absorbing surface)
raw gas
high voltage
electrode
spray nozzle
injection
drain
outlet
Images: Schräder
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Integrated ESP (1): ”Airbox” by Spartherm Feuerungstechnik
Type: Airbox (for fireplace inserts),
Supplement exclusively for manufacturer ‘s furnaces (>15 kW)
Plate-type ESP, manuelly switched-on
Manual removal of PM deposits required after 100 h operation
Status: market-available
Photo / Images: Spartherm
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Integrated ESP (2): Zumikron (by Rüegg, Switzerland)
Type: Zumikron
Developed by Rüegg (Switzerland), built by: Kutzner+Weber
Mainly for single room heaters
Use of purge air for electrode cleaning
Manual removal of PM deposits required
Status: market-available (only Switzerland)
Photo / Images: Rüegg
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Water injection for cleaning the
inner tube of the chimney
Special isolation for fixing the
high voltage electrode
Chimney made of stainless steel
Electrode made of special
type of wire
Cleaning door
Special isolation and fixing the
high voltage electrode with a
spring
Outlet for cleaning water and
condensate
Temperature
sensor
High voltage
power supply
BoilerBoiler Neutralisa
tion box
with
pump for
cleaning
circuit
ESP-Chimney-type: Feinstaubkiller (by TH-Alternativ-Energie)
Type: “Feinstaubkiller“ (ESP-chimney)
Electrode over full length of chimney
Automatic periodic cleaning by rinsing with water
from surge tank
Particle removal as sludge deposit
Status: single built and single approval
Image: TH-Alternativ-EnergiePhotos: TFZ
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Procedure of field tests performed by TFZ
• Selection of 10 private households
• Assembling of filters and automatic data recording
(electricity consumption, operating hours)
• Instruction of users concerning documentation
• Continuous operation of ESP‘s during heating period 2008/2009
• Regular cleaning and observation by chimney sweep
• Collection of deposited ash from the chimneys and the ESP‘s over the
full period and
• Determination of fuel consumption
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ESP-types applied in field test (1)
APP Residential ESP,
example here: with chimney stove (6 kW)
Photos: TFZ
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K&W Zumik®on,
example here: with cooking stove (6 kW)
ESP-types applied in field test (2)
Photo: TFZPhoto: TFZ
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P 11 B Ha 001
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Spanner SFF 20
• example here: with log wood boiler, 15 kW
• mechanical cleaning was here activated
manually by press button
ESP-types applied in field test (3)
Photos: Ritt
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Observations from field tests
Observed failures/troubles:
short circuits
failure of electrode purge air supply
burn-out of fuses
display failure
breaking of electrode
fixation problems (at chimney top)
sensor defects
high voltage failure
chimney draft problems
rain water intrusion into chimney
counteraction of ESP-purge air with furnace air supply
noise harassment
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Results field tests: electrical power input
180
14113
47
28
0
40
80
120
160
200
Betrieb Standby-Betrieb
APP Residential ESP KW Zumikron Spanner SFF20e
lectr
ica
lp
ow
er
inpu
t W
operation stand-by
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Field test results: Calculated particle reduction
Partici-
pant
Furnace ESP-type Fuel Collected
particle massb)
Theoretical
reduction of
PM emissionc)
1 Chimney stove K&W Zumikronlog wood
(spruce, pine)0.18 kg 9 mg/m³
2 Chimney stove K&W Zumikronlog wood
(spruce, pine)2.38 kg 54 mg/m³
4 a) Kitchen stove K&W Zumikronlog wood
(spruce, pine, beech)0.06 kg 5 mg/m³
5 Chimney stove APP Residential ESP log wood (beech) 0.30 kg 17 mg/m³
6 2 Chimney stoves APP Residential ESPlog wood
(spruce, pine)0.36 kg 52 mg/m³
7 Tiled stove APP Residential ESPlog wood
(spruce, pine)0.83 kg 25 mg/m³
8 Log wood boiler Spanner SFF 20log wood
(spruce, pine)3.60 kg 122 mg/m³
9 Pellet boiler Spanner SFF 20 Wood pellets 0.15 kg 5 mg/m³
10 Wood chip boiler Spanner SFF 50 Wood chips 18.59 kg 158 mg/m³
a Only ash from connecting pipe and ESP because further furnaces were connected to the same chimneyb Particle mass in ESP + connecting pipe + chimneyc Calculated from fuel mass and specific flue gas volume, based at 13 % O2
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Field test results: Investigation of PAH-content in PM deposits
Materials with more than 50 ppm PAH are considered as cancerogeneous in
Germany
Above 1000 ppm they are considered as dangerous waste.
Participant 1 2 3 4 5 6 7 8 9 10
Furnacechimney
stove
chimney
stove
tiled
stove
kitchen
stove
chimney
stove
chimney
stove
tiled
stove
log wood
boiler
pellet
boiler
wood chip
boiler
Separator K & W K & W K & W K & W APP APP APP Spanner Spanner Spanner
Total PAH 183ppm 744ppm 1344ppm 922ppm 66ppm 470ppm 1713ppm 380ppm 21ppm 197ppm
PAH-contents of PM collected from connecting pipes + ESP + chimney
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• Selection of 2 suitable chimney stoves (a simple and a high value product)
• Tests with of 2 ESP‘s (Zumik®on and APP) at both stoves 4 test series
• Tests with Spanner SFF20 at log wood boiler (simple natural draft type)
• Test duration: 5 to 6 weeks per test series (typical operation)
• Weekly measurements of particle separation in raw and clean gas
(gravimetric determination)
• Additional trials with ESP-chimney type by “TH-Alternative Energie“
Trials performed at TFZ test laboratory
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Additional tests: ESP-chimney system by TH-Alternativ Energie
Photo: TFZImage: TH-Alternativ-Energie
Water injection for cleaning the
inner tube of the chimney
Special isolation for fixing the
high voltage electrode
Chimney made of stainless steel
Electrode made of special
type of wire
Cleaning door
Special isolation and fixing the
high voltage electrode with a
spring
Outlet for cleaning water and
condensate
Temperature
sensor
High voltage
power supply
BoilerBoiler Neutralisa
tion box
with
pump for
cleaning
circuit
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Test stand setup
Dilution ratio: 1 : 4 – 6
Diluted temperature:
< 52 °C
Gravimetric PM-
determination
Measuring over the
full batch
3 fuel batches
per trial
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Test stand results:
Zumikron ESP with simple-type chimney stove
0
9
2
18
20
- 15
19
70
- 45
8
10
7
- 5- 2
37
33
29
- 50
- 40
- 30
- 20
- 10
0
10
20
30
40
50
60
70
80
-500
-400
-300
-200
-100
0
100
200
300
400
500
600
700
800
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Test No
Raw gas
Clean gas
Separation
%mg/m³n
(13 % O2)
Mean separation: 11%
Separa
tio
n e
ffic
iency
Tota
l P
M e
mis
sio
n
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P 11 B Ha 001
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Test stand results : APPResidential ESP with simple-type chimney stove
51
48
54
69
79
88 8993
48
11
11
41
78
44
50
58
29
0
20
40
60
80
100
0
200
400
600
800
1.000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Raw gas
Clean gas
Separation
%
Mean separation: 55 %
Tota
l P
M e
mis
sio
n
Separa
tio
n e
ffic
iency
Test No
mg/m³n
(13 % O2)
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Test stand results :
Spanner SFF 20 with log wood boiler (simple natural draft)
Operation without by-pass Operation with bypass
Mean separation: 25 and 80 %
11
- 41
- 89
37
66
40
69
80
50
86 96
61 55
94
88
- 100
- 80
- 60
- 40
- 20
0
20
40
60
80
100
-250
-200
-150
-100
-50
0
50
100
150
200
250
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Raw gas Clean gas
Separation
%mg/m³n
(13 % O2)
Tota
l P
M e
mis
sio
n
Separa
tion e
ffic
iency
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Test stand results :
TH Feinstaubkiller with log wood boiler (simple natural draft)
26
90 81
32
89
46
59
94
61
0
20
40
60
80
100
0
60
120
180
300
1 2 3 4 5 6 7 8 9
Raw gas
Clean gas
Separation
%
Mean separation: 64 %
mg/m³n
(13 % O2)
240
Tota
l P
M e
mis
sio
n
Separa
tio
n e
ffic
iency
Test No
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Summary and conclusions
• Three of four ESP‘s showed acceptable PM separations in both, field and
laboratory tests.
• An active mechanical cleaning of the deposited particles seems inevitable for
an undisturbed ESP-operation.
• Bevor market introduction the observed failures should be avoided reliably.
• An installation in living rooms is not accepted by the residents.
• Specific rules for handling and disposal of collected PM-mass need to be
elaborated due to the observed high PAH-contents.
• For determining the separation efficiency, a reliable and repeatable test
method needs to be elaborated.