In response to our editor's plea earlier this year for more chat on
this Network, I thought you may be interested in some comments
regarding gasification in Germany. Having just spent four
weeks there, I had the opportunity to see a few gasifiers, talk to many
students (and their Professors), other gasifier manufacturers, engine
designers, and anyone else unlucky enough to be caught up in discussion
relating to gasification.
There were also a few
project proposals to review for funding application, and
gasification equipment assessment to see if their design had the
capability to match their suppliers glowing specifications!
With so much to cover, I think it is best to make a number of reports
so that you don't get too bored ploughing through this in one go.
Gasification is a hot topic in Germany, and with the E.U. funding
renewable energy research projects, it is natural everyone who can
write a proposal is endeavoring to feed from the public
purse. It was very hard not to believe there wasn't a special
training centre hidden away somewhere on how to prepare E.U. funded
proposals. Everyone trying so hard to dress up projects to
sound new and exciting. It was difficult but necessary to
point out that just about all there is to know of any relevance is
already available in the literature.
Because my own speciality is high performance engine gasification, I
was disappointed to find that engine gasifier projects were being
proposed using process heat type gasifiers. It is a widely
held belief to those I questioned, that if it makes gas, you
can use it for anything. Furthermore if you make a
big one and fuel it with rubbish demolition wood (shredded) you can
power villages and small towns. This is tremendous enthusiasm
but difficult to accept when none had even small gasifiers operating to
commercial standards with engines.
On reflection, I haven't received any reports of reliably operating
commercially manufactured wood gasifiers in Germany except our own in
Furstenwalde. Anybody out there like to identify engine
gasifiers that can be seen working anywhere in Europe?
Possibly the projects that caused me to bristle most were those
proposing gasifier testing with different fuels, and comparing
gasifiers ability to gasify standard fuels. In the first
instance it is quite clear from reading the literature that few
projects have gasifiers operating, expertise, and no
appreciation of what constitutes a correctly functioning
gasifier. Have a look in your own library and see how many
references you can find describing behaviour of the gasifier when it is
functioning correctly. One thing for sure, any gasifier test
programme has to be invalid if the gasifier cannot be reliably
demonstrated by the manufacturer using his own approved
fuel., Then having demonstrated the gasifiers reliability,
all gasifiers that meet this requirement should have the opportunity to
participate in the test programme. If this isn't done, and
some sort of random selection of gasifiers are tested, then whoever is
conducting the tests could be seen in less than a credible
light. This is how I commented to those who presented their
proposals for scrutiny, and hopefully the rewrites will assist them to
get funds eventually.
Whilst on the subject of fuel, at several different meetings I was
asked my opinion of densified fuel (briquettes). As a
gasifier fuel, sawdust briquettes worked O.K. in our Fluidyne
gasifier, but other agricultural wastes have individual problems and
unlikely to be good fuel. There is also the point that
briquettes are energy consumptive to produce so therefore
expensive. This could be offset if the sawdust is a waste
disposal problem and the cost of briquetting charged to the waste
source. The cost of the briquettes should then cost no more than that
charged for wood chips. The idea is to produce energy from
wood, not use energy to create the fuel. The debate was
lively, and I can only conclude the briquette manufacturers are
suggesting that their fuel will solve all gas making
problems. Anybody like to comment on this?
Next report: Engines, turbines and dreamers.
an energy consultant these days is tough, and to have any
voice in the market place for your services takes something
special. In Germany or I should say the E.U. Cogen is the in
thing, so as one might expect, there are plenty of workshops assembling
Designed with the precision of a Swiss watch and squeezed with their
instrument packages into containers, all they need is a biomass rocket
to launch them into the marketplace
Without any doubt the engine manufacturers can build the engines we
need, and natural gas engines work quite well although derated on
producer gas. I spoke to several manufacturers of engines
optimising for producer gas and their reaction was sure, how many
thousand units? It was a question I needed to ask for myself,
even though it will be a miracle if the market ever demands special
The designers I spoke to were pleased for the opportunity to discuss
some of the finer points of producer gas combustion, and learn first
hand of our experiences of dual fuelling diesel gen sets. Our
first Lister engine had clocked up 5,000 hours by March 1985,
they were keen to learn about the life expectancy of standard
components. Without entering a very lengthy technical
description, the bottom line is that with clean gas, engine life is the
same or slightly better. The type of problems that can
using standard engines will of course depend on the features of that
specific engine, so I look forward to testing some of the newer gas
engine features some are incorporating into their designs.
Here are a few less known facts about producer gas and engines.
"Clean" Producer Gas:
octane anti knock properties.
combust at about 571 degrees C.
compressed up to 16:1 ratio
burning high torque fuel (like steam)
ratio 0.9/1.2:1, impossible to ignite outside of these limits, so
cannot burn lean or rich mixtures.
addition or moisture content does not enhance combustion.
or moisture in gas will carry carbon blacks through most filtration
systems, last chance separation of both is after gas/air mixer.
gases separate into laminar flows in pipelines, and after turbulence
(passing through fan) will separate again within one metre.
of dust of carbon (<10mg/Nm3) in gas is only a yardstick.
size is also important as they create impact sites on their way into
wear particles are anything over 2 microns. (Talcum powder is about 10
life is determined by acid oil erosion not wear.
cellulose filters needed on engine oil system.
There is more of course, but that is what Fluidyne sells as commercial
The potential for gasified cogen engines in the U.K. using set aside
land is considerable. Our investigations showed that using
percentages of that available, some 100,000 30kWe and 25,000 100kWe
installations were possible with coppice willow grown on the
site. With generation in such small increments, the power
existing grids at the farm gates all over the country. The
combined output of these installations 25 Twh/year is equal to Drax in
Yorkshire. Energy planners continue to think big however, and maybe in
ignorance, overlook the logistical problems of moving large volumes of
low density willow to centralised generators. Coppice willow also has
special needs as a gasifier fuel, which in large quantities, creates
some very challenging processing problems. With such a potential for
Cogen, throughout the E.U. one can only wonder at why it is almost
impossible to sell gasified installations. Economics of scale
automation are of course important, but it is a poor excuse to hold
back on legislation to enable these projects to get a leg up.
Surely it is time to bite the bullet, charge the extra for
renewables, and stop whingeing about cheap fossil fuel.
There I have to stop as I still have to work with my hands.
also make water pumping windmills and this week have mud on my
boots. One site I inspected you may have seen at the
movies. Anyone seen "The Piano" with the Oscar winning child
Anna Paquinne? Set on a rugged bush clad beach, the forest has a
brooding quality but quite beautiful and only half an hour from the
Turbines and Dreamers next week.
Fluidyne Gasification Ltd.
every country where gasification is proposed as a potential replacement
fuel, is almost mandatory to include generation for aero derived gas
turbines. I use the words proposed and potential
deliberately, because those who suggest this option have little
appreciation of the
technical challenges to be overcome. The situation in Germany
is no different and this proposal came up at almost every meeting I
1983 to 1988, Fluidyne (our company) was part of the NEI
Power Engineering Group, and we were asked to apply our understanding
of gasification to gas turbines. Only two questions were
you could get producer gas into a conventional gas turbine what would
the effect be on components.
are the practicalities of converting existing turbine design.
question one had to be hypothetical, because the combustion chambers
are too short, and the gas / air mixture would be extremely
unstable. This would cause the formation of soot due to
proportional mixing before ignition. When this soot is added
the submicron carbon blacks and alkaline moisture present in the gas,
deposits could be expected to form on the impeller blades and
buckets. Impacted carbon particles would combust in the
of free oxygen and result in surface pits and ash deposits.
was predicted that the ash would form an even but unstable skin like
coating, that would eventuate in vibrational stresses from the uneven
shedding of the skin.
question one answer, question two allowed us the opportunity to
'imagineer' the attributes of producer gas into a turbine combustion
situation. Our conclusions were that existing gas turbines
incorporated principles that made their conversion to producer gas
'difficult', and did not recommend this option of technology
adaptation. We also added that a technology development
existed if the market needed producer gas turbines.
NEEDS OF A GAS TURBINE PROJECT
quantities of very clean gas there must be no condensable
hydrocarbons (tar), pyrolysis oils or moisture in the gas stream
should not be detectable
the gasification process meets this specification, then it
should be proved by operation use in big engines
about 2,000 - 3,000 hours and the engine is still clean, it
'might' be suitable for turbine application
go and build an appropriate turbine and you are in business
manufacturers have already begun this work, my own perspective of the
gas making process puts turbine projects on hold. This
mean that our projects will be stuck with engine generation, but only
that our long term development programme will provide experienced
needed to support these expensive projects. Although turbine
manufacturers have ongoing development programmes, it shouldn't be
expected that they find solutions to problems created by the gas maker.
intention to destroy the dreams of over enthusiastic promoters of
biomass energy. Indeed we need these people in every strata
our society. If there is a need, it's to direct
towards that which is achievable and in the process, create the ability
to move forward.
companies who pursue biomass technologies as another string to their
manufacturing bow take real chances. Where the expertise of
technology relies on the employee to get it from paper to plant, the
reputation of the company can pass into the hands of the dreamers.
ability within the business sector to question the advice of the
consultants relating to gasified projects, which when they fall over,
reinforces the cry for more research. During this visit to
Germany I reviewed three projects using 800kWe electrical gasified CHP
systems that were in the hands of the dreamers. None are
operational and are in various stages of implementation as I write.
Power Station fuelled on hedge clippings - scaled up
from a 50kWe electrical double burning principle gasifier.
these small gasifiers were not commercially operable on their
designated fuel, and a third is about to be installed at an
unsuspecting technical institute for fuel testing.
Power Company fuelled on shredded wood waste - with
nondefinable secret gasification process complete with secret box gas
cleanup system. Anything is possible, but an engine supplier
informed me that an earlier project had cost them DM200,000 and dirty
gas was the main problem.
Power Company - three 800kWe gasifiers each with a single
nozzle and fuelled with shredded wood waste. Defined as an
annular hearth process, this system design has the physical
impossibility to move the volume of fuel into the area of gas making
and the velocity of the gas through the reduction zone will entrain the
fine char preventing the formation of the reduction zone.
these three projects have even reached the implementation stage without
appropriate scrutiny will create enormous distortions as to the
capability of gasified power generation. It not only reflects
badly on those who implement the project, it unfortunately tars all of
our capability with the same brush.
exists within many forms of combustion equipment although few recognise
or even pay attention to the phenomena. The transition from
gasification theory to working installations eventually requires
hammers on steel to create an environment where the phenomena of
gasification (not combustion) takes place. Every single
component, shape, size, position, surface treatment etc create complex
inter-related phenomena and performance which determine how the
manufacturing perspective it is the failure to understand the existence
of created phenomena that cause malfunction to so many gasifier
designs. If you set out to design and build gasifiers the
knowledge to do so begins at the fuel source. Each fuel has
own need of preparation, movement into the system, then gasification
after which it must be cooled, cleaned then used for whatever ...
know many who
read this gasification digest have interest and personal involvement
with this technology. From whichever aspect of your own
are you sure that your efforts are moving this technology
forward. Are you also sure you are working with up to date
information, because some of the historical information is very
misleading. With the best intentions some of us do create
problems for each other instead of providing complimentary support.
nine trips to
Germany have enabled me to share (in condensed form) some insights
which quite frankly cause me concerns which I will raise in my German
Report No 4 "High Over Europe"
day I left
Germany (22 September) we drove from Oldenburg across the dyke at the
top of the Netherlands and down to Amsterdam via a lot of side roads
(motorway problems). With a huge high over most of Europe,
North Sea was like glass and the ever present windmills still and
crawl through the side roads of the countryside, highlighted the
problems of what must be the best drained overfertilized swamp in the
in the air
I looked down on the high density housing and industrial areas of the
Netherlands and Germany, and I don't mind admitting to feeling a little
overwhelmed. Has anyone out there a calculation of
Departments to Minister of Energy exist, or how many technical
institutions advise or help formulate energy policy. How many
former biomass researchers have rotated their way through Aid Agencies
and other institutions?
about that, I have need to step back a few years to 1985, when four of
us from New Zealand went to Bandung in Indonesia for the Second
International Gasification Conference It was very expensive
attend (for those who paid their own way) but here I saw
gasification (NG) "at work" for the first time. NG is where
everything is explained, but you don't get told how to do it, and when
attempted doesn't quite work. Its nothing that another few
projects in far away places won't solve however, as no one really
checks out these projects.
origin in the heady days of the oil price crisis, when both governments
and Aid Agencies flooded technical institutes, consultancies, etc. with
rather large amounts of money. The idea was to get biomass
working, but there never was an integration of expertise and
infrastructure to ensure this could be achieved. My concerns
the direction of NG had grown considerably by 1988, and I endeavoured
to establish contact with other gasifier manufacturers. The
to form an association to represent our industry and have input into
long term planning and policies was clearly missing. It
happen as commercial manufacturers were too few at that time and busy
struggling to survive.
years since 1988, there has been a continuous rotation of NG
knowledge and it now percolates through most countries' policies
towards power generation from biomass.
announced in the U.K. of the Non Fossil Fuel Order (NFFO) it seemed
every consultant who drew breath wrote to us wanting to gasify
everything but mouse droppings. The same happened from other
countries as money came up for grabs to reduce CO2 emissions.
This scramble for money is really a matter of survival, as most
institutional activities are struggling for operational
Competing for project funds prevents pooling expertise in a
constructive manner, and it does nothing long term for the
co-ordination of effort to reduce our dependence on fossil fuels.
reality and I am high over Europe after four weeks of hard work pushing
Positive Gasification (PG).
is when every
question is answered with a lecture, every problem has a solution, and
you see your team come alive as their own knowledge is pushed and
pulled into alignment. When the penny of understanding drops,
suddenly everything changes, particularly attitude towards biomass
energy. During these four weeks our Russian speaking design
who knew nothing about gasification, went from tree to engine designing
each system with a degree of practical skill that doesn't seem to count
any more. All over 50, they are considered unemployable and
men designed, built and commissioned steel mills! The waste
industrial expertise within the EU will eventually be recognised as the
loss of a national asset, but only a dilution of their skills will
remain by the time that happens.
skills however, and redesigned our Pacific Class gasifier so that it
could be manufactured in the Ukraine. Moving Fluidyne
gasification technology into Russia is to meet the electrical shortages
of their industry, and small C.H.P. engine systems are appropriate for
their needs. The ability to meet these needs extend further
just making gasifiers and chopping wood. The implementation
programme needs supporting infrastructure such as operator training,
gasifier servicing, fuel supply and replanting of fuel
plantations. Even to create a core team in Germany has taken
three years, so to move on again is proving to be a daunting task.
are a few
questions to ponder.
did hardnosed businessmen in the UK, Germany and now Russia,
have to get their questions answered and purchase equipment half a
world away in New Zealand? What's wrong with EU technology?
can competing factions within the EU resolve biomass energy
problems without co-ordination.
poorly directed and monitored research actually created a
Frankenstein within bureaucracies, lurching around swiping us with NG
can we do to rectify the above and lots more you can name
writing of these German Reports, which I must emphasise is pure biased
opinion, I have stood up to show that a person is ultimately behind
every company name and is responsible for the technology they
present. In my chosen field of engine gasification, there are
competitors, only colleagues struggling to overcome the inertia of
also spoken for the many friends within institutes consultancies and
industry who cannot comment in such a public forum. They
all agree with my views which keeps me ever vigilant to investigate and
improve my own presentation of biomass energy.
named these as German Reports, its problems and comments are
universal. I haven't written this to impress anyone, solicit
work, sell equipment, or expand my non existent industrial
empire. Sharing knowledge of each others' activities
benefits us all.