The Viking Gasifier
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Outline
●Biomass Gasification Group at DTU
●Two stage gasification
●Viking gasifier
● Technologies
● Hurdles on the way
●Results from April 2003
●Conclusions
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Biomass Gasification Group
●Thermal conversion of biomass
●15 years of experience
●12 Employees
●Externally financed
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Two-stage gasification
✗ Separated pyrolysis
and gasification
✗ Partial oxidation of
pyrolysis gases
➔ No tar in gas
nor in waste
➔ High efficiency
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Viking gasifier at DTU
Commisioned August 2002
Small scale (75 kWfuel)
Unattended operation
Engine woodgas operation for
> 1100 hours
Waste: only ash, carbon dust
and water
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Key data April 2003
●Thermal input 68 kW
●Fuel: wood chips
●Moisture content 35-45 %
●Gasifier efficiency 93%
●Engine efficiency 32%
●Electric efficiency 27%
●Overall electric eff. 25%
●Tar level <5mg/Nm3
●Dust level <5mg/Nm3
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Materials
●Partial oxidation zone: Brick lining
●Metal 700-1100C: MA-253 high temp. steel
●Metal <700C: Stainless steel
●Baghouse filter: Polyethylene
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Bag house filter system
✗ Particle removal just
above water dew point.
✗ Filter cleaning by
N2 back flush.
➔ Bulk particles and
condensate recovered
separately.
➔ Pressure drop <100 mmWG
➔ Low energy consumption
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Gas cleaning performance
✗1200 hours of reliable
operation without permanent
increase of the pressure drop
● Dust after filter <5 mg/Nm3
Residual tar condenses on
●
particles, removed with these
➔ Tar level in gas drops
from 25 to "no tar"
(<5 mg/Nm3)
Police filter after 1200 hours
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Viking condensate quality
Amounts: 2-6 l/h
NH3: 1 g/l
Naphtalene: <20 μg/l
Other PAH: <2 μg/l
Smell: NH3
⇒ OK for standard
biological surridge plant!
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Viking dust quality from bag house filter
Amounts: 100-600 mg/Nm3
=5-30 g/h
Ash: Approx. 50%
Tar: <5% mass
➔Low temperature reburning
in boiler should be possible.
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Ash from gasifier
• Unconverted carbon in
ash from gasifier: ≈ 30 %
• Total unconverted carbon:
0.1 wt.% of fuel
0.3 % of energy in fuel
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Intake manifold of the engine after 1100
hours on Wood Gas
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Experiences
●No problems with brick lining
●Minor deposits of salts and carbonates in the hot gas
system
●No corrosion of hot metal parts
●No deposits or corrosion in clean gas system and
engine
●Shutdown corrosion in the system with cold
uncleaned gas
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Hurdles on the way
●Ash removal failed
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Hurdles on the way
●Ash removal failed
-> Totally new design
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Hurdles on the way
●Ash removal failed
-> Totally new design
●Condensation in ash
-> Heat tracing
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Hurdles on the way
●Ash removal failed
-> Totally new design
●Condensation in ash
-> Heat tracing
●Ceramics failed/smelted
-> New reactor top using
brick lining
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Hurdles on the way
●Ash removal failed Minor hurdles
●
-> Totally new design
● Valves stuck during idle
●Condensation in ash periods
-> Heat tracing ● Fuel feed blockages
●Ceramics failed/smelted ● Engine ignition system
-> New reactor using bricks
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Results during April 2003
Operation:
• Gasifier
380 hours April
(>1300 hours total)
• Engine
346 hours
(>1100 hours total)
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
50
45
40
35 Average dry gas
30
[Vol%]
25
composition
20 H2 30.5 %
15
CO 19.6 %
10
5 %
CH4 1.2
0
01-04-2003 04-04-2003 07-04-2003 10-04-2003 13-04-2003 16-04-2003 19-04-2003 %
00:00 00:00 00:00 00:00 00:00 00:00 00:00
CO2 15.4
Time %
N2 33.3
H2 CO CH4
CO2 O2 N2 LHV 5.6 MJ/N m3
Heating up Start up1 Start up2
HHV 6.2 MJ/N m3
Engine operation Shut down
Gas flow 37.1 m3/h
(dry. 0°C)
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Gas temperatures in char bed
1200
1100
Temperature [oC]
above char bed (T33)
1000
Top of char bed (T36)
above grate (T54)
900
Heating up
Start up1
800
Start up2
Engine operation
700
Shut down
600
500
01-04- 04-04- 07-04- 10-04- 13-04- 16-04- 19-04-
2003 2003 2003 2003 2003 2003 2003
00:00 00:00 00:00 00:00 00:00 00:00 00:00
Time
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
60
3
Gas flow, m /h
50
40
30
Power, kW
20
3
10 LHV, MJ/Nm
0
01-04- 04-04- 07-04- 10-04- 13-04- 16-04- 19-04-
2003 2003 2003 2003 2003 2003 2003
00:00 00:00 00:00 00:00
Time 00:00 00:00 00:00
flow: prod. Gas LHV Powerprod. Engine
Heating up Start up1 Start up2
Engine operation Shut down
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Conclusions
● Fully automatic unattended operation
● 1300 hours of operation
● 25 % efficiency from biomass to electricity to the grid.
● No tar in the gas
● Good engine performance - no deposits in engine
● Condensate not a waste problem
● Dust can be treated separately
● Absence of tars ⇒ simple, cheap gas cleaning
system.
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
Questions?
Biomass Gasification Group, DTU www.bgg.mek.dtu.dk
