August 2005 Update
Since the last update on the Mega Class Gasifier development in Winnipeg, Canada, (December 2004) the wettest winter and summer on record, has created a difficult environment to maintain the test programme schedule. With the exception of the engines, most of the work is outside without cover, so gasifier and workers have been subjected to extreme conditions.
In preparation for the continuous operation testing, some 200 tonnes of chip was prepared, but careless movement picked up stone from the unsealed yard, and was mixed through the chip. As the stone was a type of limestone, it was not noticed in the blizzard conditions that accompanied the tests, and caused considerable problems until it was discovered. All the chips are now put through a rotary screen and a hard lesson learned by everyone.
The long awaited winter testing of the condenser/gas coolers built last year, began by the moisture in the gas freezing solid as it entered the first stage condenser. It was really a start-up operating problem, and was resolved by installing a start-up gas by-pass into the system, that was left out intentionally on this test rig. This highlights one of the development pitfalls of creating problems by economizing on the ancillary equipment that is needed to support the function of the gasifier performance. In this case the start-up gas and gasifier was too cold, and required venting before the cyclones and condensers. While the condenser/cooler design is more than required for colder climates, the concepts being researched must be adequate for tropical conditions. Fluidynes earlier gasifier work in tropical countries has been used as “Yardstick” of performance criteria, and the phenomena created in this type of system, manipulated for the higher gas flows.
Having resolved the condensate freezing problem, the large volume of gas produced from 2.5 tonnes/hr chip fuel had to be combusted in a more controlled manner before commencement of the summer EPA emission tests. As winter emission tests are invalid, emphasis was placed over the winter months on destructive component testing.
In preparation for the summer emission test, the oxidation chamber already 30 feet high, had to be extended by another 30 feet, and now enables maximum gas flow testing. Just to have this piece of equipment makes the demands of proving emission standards easier to obtain. Ultimately all manufacturers are faced with the same dilemma of proving their technology, no easy task in any country as emissions become more regulated.
It has now been five years (August 2000-2005) since the MK1 Mega Class concept was first tested, and 16 months since the beginning of the MK2 trials, Most of the gasifier operating time has been used for testing components, in some cases to destruction as maximum operating parameters were established.
When a new system of gasification is being tested, a series of expected outcomes are predicted based on experience. It came as a surprise therefore, that once continuous operation began, to experience new phenomena not characteristic of downdraught gasifier performance.
The char is almost totally converted in the reduction phase leaving only a granular ash, and very little activated carbon waste. The condensate runs clear without carbon black in suspension, and the gas burns almost without colour, and without any type of filtration system. The change of gas quality can be seen by reviewing the flame colour from the first start-up shown in the first Mk2 report.
Over this summer, testing has been conducted with the assistance from the University of Manitoba, and gas analysis being done at EERC in Grand Forks, by Darren Schmidt's team. This has resulted in a correction of when the gas tests commence in relation to the start-up time of the gasifier, so that the whole system is temperature stabilized before test samples are collected.
After a lot
of discussion it has been decided to shelve the multiple V8 engine generation
system, and an association has been made with a specialist company who provides
large engines for power generation. They have provided a 500kWe dual fuel
engine as a test facility, and will use this to obtain operating data for
larger (>2MWe) engines.
At 10 tonnes for the 500kWe engine a new concrete foundation had to be laid
for its mounting, again requiring a lot of effort to just run the engine on
some of the gas. Surplus gas is to be flared. This engine will be operational
August 2005.
Nothing has been done on the fuel feeding system at this point in time, but they advise a new system will be developed shortly.
It is expected that all the systems will be in place before the end of 2005, and information will be released as it becomes available reliably tested.
For those interested in the clean gasification of coal, I can only say at this time, that biomass is the emphasis of the current development programme. We have gasified sulfurous nut grade coal with observable good results, but that was just to see how the process handled coal. It would seem that this design could make the switch to syn gas as an oxygen blown system, but that would require some serious input of $$$, and additional technicians on the team. If the need and money are there to support that need, air gasified low grade coals can be achieved, given the time required to obtain certified test results for permits and EPA emissions standards.
The selected
photos show some of the details mentioned, and provides some idea of how much
effort is required to develop large gasification systems.
These can be seen on the Fluidyne Archive www.fluidynenz.250x.com
Doug Williams.
Fluidyne Gasification.
gasifer 001.jpg
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This shows the rotary screen used to clean the stone out of the wood chips. The elevator was loader fed from the stock pile and after screening, elevated into the 40' moving floor trailer storage. |
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Here
you can see the condenser/gas cooler, with the surface rusted cyclones
on the right. |
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The
scaffolding around the oxidation chamber provides access to the test
ports for the emission tests, and the horizontal extension of the chamber,
can be seen coming in from the right.
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Seen against a blue sky, the gas straight out of the gasifier, without cycloning, filtering, or cooling, burns almost without colour. Compare this flame from that show on the first Mk2 test firing April 2004 to see the reduction of sub micron carbon blacks, and uncracked hydrocarbon, that was leaking through an undetected sealing failure. |
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These are the sieved fuel chips, but as a fuel are far from perfect. |
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Ideal chips are not shredded and long, but crisply cut into about 2” length, and consistent in thickness. www.laimet.com This link will connect you to what we consider to be the best chipping system for commercial gasification fuel. |
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This 500kWe Mirrlees dual fuel engine and alternator will be used to establish operating performance for a range of larger engines. Of particular interest is that the engine is set up for bio diesel, and this facilitates further reductions of fossil fuel emissions. |
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