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Wood to Bio-Methane
demonstration project in the
Netherlands
C.M. van der Meijden (ECN)
J.W. Könemann (Dahlman)
W. Sierhuis (HVC Group)
A. van der Drift (ECN)
G. Rietveld (ECN)
June 2013
ECN-M--13-009
Wood to Bio-Methane demonstration project in the Netherlands
Christiaan van der Meijden1*, Jan-Willem Könemann, Wil Sierhuis3, Bram van der Drift4 & Bert Rietveld5
1 Energy research Centre of the Netherlands (ECN), P.O. Box 1, 1755 ZG Petten, The Netherlands,
Phone: +31 224-564582, E-mail: vandermeijden@ecn.nl
2 Dahlman Renewable Technology, P.O. Box 438, 3140 AK Maassluis, the Netherlands, E-mail: j.w.konemann@dahlman.nl
3 HVCgroup, P.O. Box 9199, 1800 GD, Alkmaar, Phone +31 725411311, w.sierhuis@hvcgroep.nl
4 ECN, Phone: +31 224-564515, Fax: +31 224-568487, E-mail: vanderdrift@ecn.nl
5 ECN, Phone: +31 224-564504, Fax: +31 224-568487, E-mail: g.rietveld@ecn.nl
ABSTRACT: The Energy research Centre of the Netherlands (ECN) has developed a biomass gasification technology,
called the MILENA technology. The Milena gasification technology has a high cold gas efficiency and high methane
yield, making it very suitable for gas engine and turbine applications as well as upgrading of the gas into Bio-Methane.
An overall efficiency from biomass to power of over 30% is possible, whereas 70% efficiency is achievable from biomass
to gas grid quality methane.
HVC Group (situated in Alkmaar, North Holland) is a modern public service waste company. HVC converts waste
streams which cannot be recycled into usable forms of energy. HVC has a 75 MWth waste wood boiler in operation
which produces heat and electricity, and an anaerobic digester which converts domestic fruit, vegetable and garden waste
into Bio-Methane. HVC expects an important role for Bio-Methane in the future and HVC has decided to join ECN with
the development, demonstration and implementation of the MILENA Bio-Methane technology.
Linked to the Bio-Methane demonstration project is the Netherlands Expertise Centre for Biomass Gasification. The
MILENA demonstration project and the Gasification Expert Centre are supported by the following companies and
organizations: HVC, TAQA, Gasunie, Dahlman, province of North Holland, the Alkmaar municipality and ECN.
In 2010 and 2012 extensive lab-scale and pilot scale tests have been executed by ECN and HVC to proof that the
gasification and gas cleaning technology is ready for commercial application. The final step in this test program was a
duration test in the 800 kWth MILENA pilot plant coupled to the OLGA tar removal unit. The goal was to show high
availability. The result of the test was an availability of the gasifier of 96% and an overall availability (including gas
cooling and gas cleaning) of 85%. The results of the duration tests convinced HVC and the other partners that the
technology is ready for scale-up.
The results produced in the lab-scale and pilot scale installation were used to design the scaled up version of the
MILENA gasifier and were also used to define and optimize the overall wood to Bio-Methane system.
The last two years a lot of effort was spent to form the consortium and arrange the subsidies required for this
demonstration project. At the moment Dahlman, licensee of the MILENA and OLGA technology, is doing the detailed
engineering of the plant. The final investment decision is anticipated for the summer of 2013, start of construction of the
demonstration plant is scheduled for 2014.
Keywords: dual fluidized bed, demonstration, allothermal gasification, biomass conversion, bio-syngas, gasification,
methane, synthetic natural gas (SNG).
1 INTRODUCTION
Natural gas plays an important role as an energy
source worldwide. Natural gas is a relatively clean
primary energy carrier and is therefore often the fuel of
choice in many regions of the world.
Replacing part of natural gas by Bio-Methane, produced
from a sustainable primary energy source, with the same
properties as natural gas facilitates the implementation of
sustainable energy since natural gas grids are widespread
in many countries.
A Substitute Natural Gas can be produced from biomass
(Bio-SNG or Bio-Methane) with a high efficiency and
with low emissions from the plant itself (comparable with
modern power plants).
Biomass transport can be limited by locating the Bio-
Methane production facility where the biomass is
collected, but this limits the size of the installation. Large
scale installations would benefit from a location next to
harbors.
Gasification technology, in combination with gas
cleaning and catalytic conversion of the gas offers the
possibility to convert a solid biomass into a gas with the
same properties as natural gas.
Biomass gasification technology is still under
development. A limited number of demonstration plants
and commercial plants is in operation. Successes with
these first plants have resulted in an increasing interest
for biomass gasification. Several biomass gasifiers in
combination with gas engines are under construction at
the moment. Most of these gasifiers use clean wood as a
fuel. The ECN development is focused on also using
waste as fuel.
ECN (Energy research Centre of the Netherlands) has
developed an indirectly heated (allothermal) biomass
gasification process (MILENA), optimized for the
production of Bio-Methane, but the gas can also be used
in boilers, gas engines, gas turbines or the production of
Fischer-Tropsch diesel. The MILENA fluidized bed
gasifier is fuel flexible. An extensive test program was
done to prove that the MILENA gasifier can handle
demolition wood and that the availability of the
installation is sufficient for commercial application. The
data obtained from duration tests done in the pilot plant
in 2010 and 2012 were used to design a 12 MWth
demonstration plant that will be constructed in Alkmaar
in The Netherlands. A similar plant is under construction
in Goteborg, based on the FICFB gasification technology
developed by Technical University Vienna.
2 MILENA GASIFICATION TECHNOLOGY
The first design of the MILENA gasifier was made in
1999. The first cold flow, for hydrodynamic testing, was
built in 2000. Financing a lab-scale installation appeared
to be problematic, because there was no interest in a new
gasification technology at that time. This changed when
SNG was identified as a promising bio-fuel. The
construction of the 30 kWth MILENA installation was
started in 2003. The installation was finished and taken
into operation in 2004. Financing of the 800 kWth
MILENA pilot plant was approved in 2006 and the
construction was finished in 2008.
The MILENA gasifier contains separate sections for
gasification and combustion. Figure 1 shows a simplified
scheme of the MILENA process. The gasification section
consists of three parts: riser, settling chamber and
downcomer. The combustion section contains two parts,
the bubbling fluidized bed combustor and the sand
transport zone. The arrows in Figure 1 represent the
circulating bed material. The processes in the gasification
section will be explained first.
Biomass (e.g. wood) is fed into the riser. A small
amount of superheated steam (or any other gas available
including air) is added from below to enable bed material
circulation in the bottom of the riser reactor. Hot bed
material (typically 925°C sand or olivine of 0.2-0.3 mm)
enters the riser from the combustor through a hole in the
riser. The bed material heats the biomass to 850°C. The
heated biomass particles degasify; they are converted into
gas, tar and char. The volume created by the gas from the
biomass results in a vertical velocity of approximately 6-
7 m/s, creating a “turbulent fluidization” regime in the
riser and carrying over of the bed material together with
the degasified biomass particles (char). The vertical
velocity of the gas is reduced in the settling chamber,
causing the larger solids (bed material and char) to
separate from the gas and fall down into the downcomer.
The producer gas leaves the reactor from the top and is
sent to the cooling and gas cleaning section. Typical
residence time of the gas is several seconds.
The combustor operates as a bubbling fluidized bed
(BFB). The downcomer transports bed material and char
from the gasification section into the combustor. Tar and
dust, separated from the producer gas, are also returned
to the combustor. Char, tar and dust are burned with air
to heat the bed material to approximately 925°C. Flue gas
leaves the reactor to be cooled, de-dusted and emitted.
The heated bed material leaves the bottom of the
combustor through a hole into the riser. No additional
heat input is required; all heat required for the
gasification process is produced by the combustion of the
char, tar and dust in the combustor.
The flue gas leaving the MILENA installation is
cooled down to approximately 100°C and is cleaned in a
bag house filter. If clean wood is used as a fuel no
additional flue gas cleaning is required.
The hot producer gas from the gasifier contains
several contaminants such as dust, tar, chloride and
sulfur, which have to be removed before the catalytic
conversion of the gas into Bio-SNG. All fluidized bed
gasifiers produce gas which contains some tar. Tar
compounds condense when the gas is cooled, which
makes the gas very difficult to handle, especially in
combination with dust. The producer gas is cooled in a
heat exchanger, designed to treat gas which contains tar
and dust. The heat is used to pre-heat combustion air. Tar
and dust are removed from the gas in the OLGA gas
cleaning section [1]. The OLGA gas cleaning technology
is based on scrubbing with liquid oil. Dust and tar
removed from the producer gas are sent to the combustor
of the MILENA gasifier. The cleaned producer gas,
containing mainly CO, CO2, H2, CH4, C2H4 and C6H6
can be used in gas boilers, gas engines or gas turbines.
Gasifier
Flue gas
Steam
Air
Producer
gas
Tar +
dust
Biomass
Circulating bed material
Biomass particle
Char particle
Figure 1: Simplified scheme of MILENA gasifier.
The overall theoretical cold gas efficiency of the
gasification process including tar removal is 78% on
LHV basis and 76% on HHV basis when wood chips
with 25 wt.% moisture are used as fuel. Efficiency can be
improved by using low temperature waste heat for
biomass drying.
To produce Bio-SNG, further conversion of the
cleaned producer gas into a mixture of CH4, CO2 and
H2O is done in catalytic reactors. After compression and
removal of the H2O and CO2 the Bio-Methane is ready
for gas grid injection or can be used as transport fuel. If a
surplus of H2 is available (produced from a surplus of
renewable electricity) this can be mixed in before the
methanation catalysts. By mixing in H2 the overall
conversion of carbon in the gas (present as CO and CO2)
will increase.
3 PILOT PLANT
3.1 Design of pilot plant
The goal for the pilot plant was to realize an
installation, which can be used to do experiments under
realistic ‘commercial’ conditions. This means no external
heat supply to the reactor and an increase in fuel particle
size from 1-3 mm for the lab scale installation to <15 mm
for the pilot plant. The lab scale installation is limited in
fuel particle size because of the size of the feeding screw
and riser reactor. For the pilot plant an upper size limit of
15 x 15 mm was selected because of limitations in the
feeding system. A simplified scheme of the MILENA
installation connected to existing gas coolers, gas
cleaning and boiler is given in Figure 2.
Biomass
Flue gas
Steam
Tar + dust
White
ash
Burner
Boiler
OLGA
Flue gas
Wet
Scrubbing
MILENA
Figure 2: Schematic overview of pilot installation.
Producer gas from the pilot MILENA gasifier is
cooled from approximately 850°C to 500°C in a double
pipe cooler [2]. Most of the dust in the gas is removed by
a cyclone. This dust stream contains ash, small bed
material particles and char. This stream will be recycled
to the MILENA combustor in commercial size
installations. Tar and the remaining dust are removed
from the producer gas in the OLGA gas cleaning section.
Heavy tars and dust will be pumped to the MILENA
combustor. The light tars are stripped with air from the
OLGA absorption fluid (oil) and are used as combustion
air. Ammonia, chlorides and water can be removed from
the gas by the wet cleaning system [3]. A booster
increases the pressure of the gas to 70 mbar in the pilot
plant. The gas pressure was required in the past to use the
producer gas as fuel for a gas engine. No gas engine tests
are planned for the future, because tests have shown that
gas engine operation is straightforward as long as the tar
dew point temperature is above the lowest temperature in
the gas engine gas supply system. The cleaned producer
gas is combusted in a gas boiler in the pilot plant at ECN.
The flue gas from the MILENA combustor is cooled
to 150°C. Part of the heat is used to pre-heat the
combustion air. The flue gas is cleaned in a bag house
filter before the flue gas is sent to the stack.
The basic design data for the MILENA gasifier fueled
with dry wood pellets is given in Table I. The tar in the
producer gas and some of the benzene and toluene are
removed from the gas in the OLGA gas cleaning. The tar,
benzene and toluene are used as fuel in the combustor.
Table I: Basic design data MILENA pilot plant.
Thermal input (HHV basis)
[kW]
797
Biomass mass flow
[kg/h]
158
Steam to gasifier
[kg/h]
19
Riser diameter [m] 0.2
Combustor diameter
[m]
0.8
Overall reactor height
[m]
8
Circulation rate bed material [kg/h] 6300
Producer gas volume flow wet [mn
3
/h] 174
Tar and BTX to combustor
[kW]
55
HHV gas wet basis excl. tar
[MJ/m
n
3]
13.1
HHV gas dry basis excl. tar [MJ/mn
3
] 18.0
3.2 Demolition wood duration tests
A duration test on demolition wood was done in the
autumn of 2010 in cooperation with operators from HVC
[4].
The demolition wood used was of the so called ‘B’
quality according to Dutch qualification. This means that
it includes painted waste wood and particle board. It must
be noted that the composition of the demolition wood
varied strongly during the tests, some batches contained
large amounts of particle board material and others
contained significantly more gypsum board material than
average.
In total 243 hours of operation of the entire plant
were recorded during the 2010 duration test. The first
half of the test was done with clean wood pellets, the
second half with demolition wood. During wood pellets
operation the MILENA gasifier ran without any
problems. During waste wood operation the gasifier had
to be shut down twice because of accumulation of glass
in the riser. The bed material discharge was increased to
prevent accumulation of the large particles. Most of the
other shut downs were caused by fouling of the piping
that connects the gasifier to the gas cleaning. The
distance between the gasifier and gas cleaning is
relatively long, because there was no room in the gasifier
building to place the gas cleaning. This was the major
cause for the clogging of the piping. For commercial
plants this should not be an issue, because the gas
cleaning is placed next to the gasifier.
The tests showed that the MILENA can gasify waste
wood, but the availability of the installation was not
sufficient for commercial operation. Therefor it was
decided to modify the piping between the gasifier and the
gas cleaning and to try to reduce the tar dew-point to
improve the availability of the system.
3.3 Duration tests using wood chips
In preparation of the new duration tests several bed
material tests were done in the lab-scale and the pilot
scale installation to reduce the tar dew point to reduce
problems in the piping between the gasifier and the gas
cleaning. The lab-scale test results were very promising.
Reduction of the heavy tars by a factor of 5 was possible
(see Figure 5), so it was decided to do bed material tests
at pilot scale as well. One of the pilot scale tests done
was the addition of dolomite to the bed, because the
catalytic activity towards tar cracking of dolomite is well
known. During the pilot scale tests with dolomite as an
additive the flue gas cooler got clogged. Because of time
and budget constrains it was decided not to continue with
adding dolomite to the bed. It was also decided to
continue the duration test with Norwegian olivine,
because most of the operational experience was gained
with this bed material, despite the fact that the catalytic
activity towards tar reduction is very low. Fouling
problems in the piping were prevented by adding an
mechanical cleaning device Figure 3 shows the measured
gas composition during the 2012 duration test. Air
instead of steam was used as fluidization gas for the riser,
this dilutes the gas somewhat. Air was selected because
the intended usage of the gas was in gas engines; a small
amount of N2 in the gas is acceptable for gas engines (or
gas turbines). When the gas will be used for Bio-Methane
production the riser will be fluidized with steam to
prevent N2 dilution. The advantage of using air over
steam is the increased overall efficiency, because for the
production of steam water needs to be evaporated.
The tar content of the gas was during this test were
very high. The highest measured tar concentration was 73
g/nm3 of which 8.5 g/nm3 was class 5 tars. Despite this
high tar content fouling of piping was not a problem. The
online cleaning system worked very well.
The primary goal of the 2012 duration test was to
show that the integrated installation (MILENA gasifier +
OLGA tar removal) could be operated with a high
availability. Figure 4 summarizes the availability of the
complete installation during the 500 hours that operators
of ECN and HVC were available to run the installations.
Most stops were related to the feeding system. Most
of these problems were fixed within minutes, but some
required emptying the complete dosing bunker. The
overall availability of the system was 85%. The
commercial partners were satisfied with this result.
3.4 Tar control
The clogging problems in the piping and the producer
gas cooler are related to the concentration of heavy tars in
the producer gas. Lighter tars like naphthalene do not
give problems in the cooler, because the wall temperature
of the cooler is well above the dew point of the light tars.
Experiments with different bed materials and additives
have shown that it is possible to lower the concentration
of heavy tars in the MILENA producer gas. The catalytic
activity of the bed material changes over time, because of
changes in the surface composition of the bed material.
The use of catalytic bed materials and additives increase
the cost of operating a gasification plant, so a continuous
monitoring of the tar concentration is required to keep
operational costs for bed materials and additives low.
ECN developed an online tar measurement device in the
past [5], but this device was only able to do
measurements after tar reduction devices. It was useful to
monitor gas cleaning processes like the OLGA tar
removal technology, but can not be used to optimize
fluidized bed gasifiers. No online devices are available to
measure heavy tar concentrations in raw gas. To
overcome this problem a relation was sought that was
able to use the continuous measured gas composition to
get an indication if the bed material was still catalytically
active. The ratio of CO2 * H2 / CO² appeared to give a
good indication for the concentration of heavy tars in the
MILENA gasification process. Figure 5 depicts the
measured class 5 tars and the mentioned gas composition
ratio for woody fuels.
Figure 4: Availability of the MILENA installation
Figure 3: Measured gas composition during 2012 tests
campaign (air used as gasification medium).
4 BIO-METHANE SYSTEM LAYOUT
The overall efficiency from wood (25 wt.% moisture)
to bio-methane is expected to be near 70% (LHV basis,
including electricity consumption) for commercial size
installations based on indirect gasification [6]. Several
process layouts are possible, all with their advantages and
disadvantages. ECN selected the process layout as shown
in Figure 6. The MILENA gasifier and OLGA tar
removal unit are operated near atmospheric pressure.
After tar removal water is removed from the gas, because
this is required for the compressor. The removal of water
is undesired because water is required later on in the
process. The gas pressure is increased to a few bar. It is
expected that the operating pressure of the MILENA
gasification technology will be increased to a few bar, so
the gas does not need to be compressed anymore and the
water can stay in the gas.
A Hydro-DeSulfurization (HDS) catalyst is used to
convert organic sulfur compounds (thiophenes) into H2S,
because the removal of organic sulfur compounds is not
possible with the foreseen sulfur removal technologies to
a sufficiently low level (<< 1 ppm). The HDS reactor is
operated above 300°C, so the gas needs to be heated
before the catalysts and is cooled again after the HDS
unit. Many different technologies are available for the
removal of H2S (and COS). ECN uses ZnO in their lab-
scale installations. ZnO will be used as a guard bed after
a bulk sulfur removal technology in the demonstration
installation. After Sulfur removal a pre-methanation or
pre-reforming step is foreseen. In this the catalytic reactor
the higher hydrocarbons (e.g. benzene and toluene) are
reformed and some of the syngas is converted into
methane. The typical operating temperature of the pre-
reformer is between 550°C and 600°C. The reform
reactions are endothermic, but the methanation reactions
are exothermic, this makes the overall reaction adiabatic
or slightly exothermic. Before the pre-reformer the gas
needs to be heated and after the heat exchanger cooling is
required. Some steam is added to the gas to prevent the
formation of soot on the catalyst surface. The need for
heat exchangers for the HDS and Pre-reform reactors is
one of the disadvantages of this system layout.
Cooler OLGA
HDS Adsor-
bents Reformer
Multi stage
fixed bed
methanation
Amine
scrubber
Dryer
Milena
Bio-Methane
Biomass
steamair ash
Cl + S carbon
dioxide
heavy & light tars
dust
Cyclone
Figure 6: Prefered Bio-Methane system layout.
After the conversion of the higher hydrocarbons an
conventional amine scrubbing system can be used to
remove approximately 85% of the CO2 from the gas. The
only hydrocarbon that will dissolve in the amine liquid is
CH4, but the solubility of CH4 in amine liquids is very
low al low pressures compared to the alternative CO2
removal technologies, so the overall CH4 loss is
relatively low. The saturated amine scrubbing liquid is
regenerated. The CO2 and the very low CH4
concentrations are vented into the atmosphere. The basic
idea behind this layout is that the CH4 emissions of the
system should be minimized, because the driver for
producing Bio-Methane is the reduction of greenhouse
gasses. The contribution of CH4 to global warming is 25
times more than for CO2, so methane slip in a Bio-
Methane plant should be minimized. The disadvantage of
amine scrubbing is the requirement for a significant
amount of heat to regenerate the amines, but in the
foreseen system this heat (temperature level 130°C) is
available. Another benefit of this layout is the reduction
in gas volume that needs to be compressed.
After CO2 and water removal the remaining gas is
compressed to the typical operating pressure of
commercial methanation catalysts. The methanation
reactors are normally placed in series with cooling in
between. A gas recycle might be used to limit the
temperature in the reactor. The CO2 removal is tuned in
such a way that the remaining CO2 reacts with the
surplus of H2 in the gas to CH4 and H2O. After removal
of the produced water the gas is ready for gas grid
injection.
One of the possible issues with the reforming and
methanation is the formation of soot. To reduce the
chances of soot formation the process conditions in the
pre-reformer and methanation reactors are chosen such
that in theory no soot is produced. Figure 7 shows the
CHO diagram for the conditions in the pre-reformer.
Steam is added to the gas to keep the operation point
below the soot formation lines.
Figure 5: Concentration of heavy tars as function of gas
composition ratio for many different test conditions.
Figure 8 depicts the operating conditions for the
methanation reactor. The operating point is on the line
between H2O and CH4. This means that there is no need
for CO2 removal anymore after the methanation, only
water removal is required.
Figure 8: CHO ternary diagram methanation
conditions
5 BIOMETHANE DEMONSTRATION PLANT
After a delay of more than two years the engineering
of the MILENA demonstration installation was continued
in 2013. The delays were caused by changes in the Dutch
subsidy regime and an extension of the consortium for
the demonstration with Gasunie and other partners. In the
present configuration most of the gas will be burned in a
gas boiler to produce medium pressure overheated steam.
This steam will be used to produce electricity in an
existing steam turbine. Figure 9 depicts the
demonstration plant.
The MILENA development has attracted attention
from other industrial companies as well. Thermax, a large
boiler manufacturer from India, has selected the
MILENA technology to convert local biomass waste
(soya residue) in gas for gas engine application. An 1
MWe demo plant is scheduled for construction in 2013.
Figure 9: 12 MWth MILENA demonstration plant.
Test done with demolition wood in the pilot plant
have resulted in an interest from several companies in the
application of MILENA and OLGA for gas production
for gas engines. Several commercial offers are under
discussion at the moment. In 2013 ECN and Royal
Dahlman have signed a license agreement for the
MILENA technology. Royal Dahlman already has the
license for the OLGA tar removal technology, so they are
now able to offer completely integrated solutions for the
production of a clean gas from biomass and waste.
Further scale up (to over 100 MWth) is another topic
of development. Preliminary designs have shown that this
is a viable option. The integrated one vessel concept
makes pressurization of the process relatively simple; this
is advantageous for further scale up.
5 FUTURE OUTLOOK
ECN is still working on improving biomass
gasification systems. Some of the interesting
developments that are related to the MILENA
demonstration are:
• Production of Bio-LNG (Liquid Natural Gas)
by cryogenic separation of CH4 from the gas.
• Separation of benzene and toluene from the raw
gas in combination with the production of Bio-
LNG or gaseous Bio-Methane
• Separation of ethylene from the raw gas,
possibly in combination with option mentioned
above.
• Co-production of Bio-Methane with Fischer-
Tropsch diesel.
ECN is already testing some of the mentioned options
using the lab-scale and pilot scale MILENA gasifiers.
One of the goals of the Biomass Gasification Expert
Centre is to use gas from the demonstration plant to do
continuous testing of different concepts / catalysts. The
advantage of using the demonstration plant is that the gas
will be available continuous whereas nowadays only
duration tests of a few hundred hours can be done.
6 CONCLUSIONS
The MILENA Bio-Methane development has been
ongoing for several years now. The technology has been
extensively tested on lab-scale and pilot scale. The
duration tests done in 2010 have shown that the system
can handle demolition wood. The 2012 duration tests
Figure 7: CHO ternary diagram, dot represents
pre-reformer conditions.
have shown that the reliability and the availability of the
technology were increased significantly and have
convinced the commercial partners to start a
demonstration project.
The overall system from wood to Bio-Methane was
optimized with the aim to maximize efficiency and taking
into account the practical limitations that resulted from
the experimental work that was done using the lab-scale
methanation test rig.
It is expected that the construction of the Bio-
Methane demonstration tests will start this year. The
consortium that was formed to demonstrate this
technology has decided to continue this development but
is still waiting for the final approval of subsidies. The
MILENA Bio-Methane demonstration plant will be part
of the Biomass Gasification Expert Centre. Gas produced
by the demonstration plant will be made available for
testing of other new (catalytic) conversion technologies.
7 ACKNOWLEDGEMENTS
A large part of the work described here is financed by
the Dutch Agentschap NL agency and HVC. Their
financial support is greatly acknowledged.
8 REFERENCES
[1] Boerrigter, H., Van Paasen, S.V.B., Bergman,
P.C.A., Könemann, J.W., Emmen, R., Wijnands,
A., 2005. OLGA tar removal technology, Petten,
The Netherlands, ECN, ECN-C--05-009.
[2] Van der Drift, A., Pels, J.R., 2004. Product gas
cooling and ash removal in biomass gasification,
ECN, Petten, The Netherlands, ECN-report: ECN-
C-04-077.
[3] Rabou, L.P.L.M., 2004. Ammonia recycling and
destruction in a CFB gasifier, The 2nd World
Conference on Biomass for Energy, Industry, and
Climate Protection, 10-14 May 2004, Rome, Italy.
[4] Van der Meijden, C.M., van der Drift, A., 2011.
Waste wood gasification in an allothermal gasifier.
In: European Biomass Conference 2011.
[5] Vreugdenhil, B.J., Kuipers, J., 2008. Tar Dew
Point Analyzer as a Tool In Biomass Gasification.
In: 16th European Biomass Conference, 2-6 June
2008, Valencia, Spain.
[6] van der Meijden, C.M., 2010. Development of the
MILENA gasification technology for the
production of Bio-SNG. Thesis, TU Eindhoven,
205 p.
ECN-M--13-009 3
ECN
Westerduinweg 3 P.O. Box 1
1755 LE Petten 1755 LG Petten
The Netherlands The Netherlands
T +31 88 515 4949
F +31 88 515 8338
info@ ecn.nl
www.ecn.nl
