[Gasification] Fluidyne Update

Doug Williams doug.williams.nz at gmail.com
Tue Feb 24 12:32:16 CST 2015


Fluidyne California

Shasta 2 Gasifier.

Since the Shasta 2 Gasifier at CalForest Nurseries in California was put
work in February 2014 for the Winter heating, it's operation completed over
1,000 hours of daily operation without failure of any component. The next
1000 hours had failures of fuel lock seals allowing leaks into their
actuating motors so will be now replaced with separated actuators. The
system was able to demonstrate a push button start from cold (after checks
to all the fuel feeding conveyors) and walk away operating reliability for
the day/night operation.

The boiler pipelines have now been extended into a second greenhouse for the
2015 Winter heating, and indications are that there is still plenty of
additional heat in reserve. The first start of this year did bring surprise
however, in that the wood chip being gasified had a moisture content of 40%.
The Shasta 2 still made a combustible gas, but initial ignition of the
burner nozzle was difficult on the standard air setting, so less air and it
ignited immediately. Wet wood isn't an option but the log pile was left open
without its covers, and a lesson was had by all concerned.

Biochar Making Project.

It's been almost two years since my last visit to CalForest, and my visit in
the last week of January 2015 was of special significance to commission a
new concept of continuous charcoal manufacture. The conceptual process was
first proposed in 2007, but put on the back burner as the focus was on
gasifier development for heating and engine power generation. While biochars
have a role to play within the Nurseries of CalForest, as a commercial
product, it's production costs are an inhibiting factor for those consumers
who need large quantities. With forest fires a problem in many countries,
fuel reduction programmes within forests sees large amounts of green forest
chip becoming available, with a potential for char making.

As stated, the target fuel is green forest chip, which at best does not make
good quality char for barbecue or cooking applications. The cost in time for
retort type charring to capture the pyrolysis gas cannot be justified if the
end result is only a char that then needs briquetting before it can be used.
As a tonnage production, it's application as biochar is of course dependent
on price to the end user, and our project is designed to explore the
potential to reduce costs of the production cycle. 

Starting in November 2014, the original char maker design concept was
reviewed and a few changes made as to how the char extraction was
accomplished, but to first prove these changes, a wooden model was built.
Char collected from the Shasta 2 waste clean outs were used to obtain the
fluid flows expected from forest chip fine char providing a visual
demonstration that the extraction process was very stable across the length
of the bed. As a base line specification, we were looking for 5-7 m3/hr, or
roughly 1 ton/hr from about 5 ton green chip. Availability was set at a
reasonable 1,900 hrs/year depending on location which would see a reduction
of forest fuel of roughly about 9,500 tons/unit. With fuel flows of that
order, we had to use the main fuel feeder conveyor of the Shasta 2 gasifier,
combined with a lot of observation (and shouting) to run it all manually.
The proto-type was completed in the last week of January 2015.

Based on previous knowledge regarding the chars ability to retain uncracked
pyrolysis oils and tars (creating a strong acetic or acrid smell), the need
for a char of consistent quality and evenness of carbonisation, identified a
design need to even out all these variables. Linked with a dwell time
between the refuelling cycles, we soon discovered that anything less than
complete carbonised char created operational problems to the extraction
system, but once we learnt to start the system correctly, these issues were
resolved.

Built as a test of concept, the charmaker was proven to function within our
pre-set design parameters, which now justifies the next phase of
development.
This includes a internal fuel pile leveller/refuel sensor, heat resistant
air nozzles, and change to the extraction auger design. Flare stack closures
will facilitate the shut down procedure, as will fuel feeder locks on the
fuel input end to exclude all free air entry. The start-up from ignition to
gas burning at the flare stack was faster than anticipated once we found the
ideal air flow settings, and 5-10 minutes gave us time to be closely
watching all the visible phenomena, especially the oxidation colour through
the air nozzles creating temperatures well over the 1,000C. The pyrolysis
gas was burnt to waste cleanly, demonstration that it could become a
reliable source of close coupled heating as required.

Although we have designed a charmaker for chips, it's performance factors
should also apply to any nut shell or fruit stone/pip, which in time will be
tested with results shown on the Fluidyne Archive files. Also to be tested
is tar free gas extraction to run an auxiliary engine generator for stand
alone operation of the system.

Photos of this project can be seen on the Fluidyne archive
www.fluidynenz.250x.com and will be available to see in about 7-10 days from
this posting.

Hope this is of interest to those following our development programme.

Doug Williams,
Fluidyne.









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