Tasman Class Gasifier

Gasification Australia, a newly established small company in Melbourne, Australia, has commenced the component trials for the 10-15 kWe Tasman Class gasifier in August 2006, using Licensed technology from Fluidyne Gasification.

Originally intended to supply a growing demand for a basic small gasifier from within Australia, wider interest has required variations to be considered within the design parameters.

The design criteria, requires that it be simple to operate without automated controls, or water for gas cleaning. Some degree of portability had to be considered, providing the capability for the system to be loaded for application in a transport role. Gas output to fit into this dual role took into consideration the average engine of a small pickup truck, and a 3 litre engine has been targeted.

Gas cooling in the extremes of tropical environments, is a focus of development to minimize loss of engine performance due to loss of volumetric efficiencies. Heat exchangers for producer gas are not a stock item for suppliers, and innovation is required to build a trouble free, simple system.

Licensed technology requires more than just a set of construction drawings to become a gasifier manufacturer, and experience has shown that what may be easy to do in one country, is impossible in other places. Most of the development work that has to be achieved using pre-production systems, is to redesign around locally available materials, and components, which if imported can increase the cost of production,.

Many potential users of gasifiers find that engine generators are not sized correctly for producer gas, loosing 50% of their power compared to gasoline. This does refer to spark ignition engines, as most small diesel generators have incompatible compression ratios.
To over come this problem, rebuilt engines from scrapped vehicles are considered a resource that cannot be ignored, and generators built using these engines. It is not thought that these could be offered for sale, as many clients have DIY capability, and practical advise will be offered to assist these projects.

The extreme hardwood fuels found in Australia are not a problem to gasify, but the universal problem of fuel preparation into small pieces remains to be resolved. We consider this to be one for local consideration if planning to use these gasifiers for stand alone power generation.

The following photographs were taken in August 2006 during these first trials of component testing. It is expected to be able to report on the finished design in October, and a further set of photos will be posted.

Doug Williams.
September, 2006.

 

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Side view of gasifier set up to test cyclone and cooler/condenser concept with 12volt fan.

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Air flows from 12 volt fan proved to be strictly limited for reliable continuous operation, but considered an option for special case installations.

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Hinged panels will enclose the hot components, opening for clean out servicing.

The small fuel hopper is sized for the testing programme, and will be double height in final design allowing about 2hours operation between fills.

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Simple manometers measure the pressure drops across assemblies.

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This 3 litre engine has been set up to obtain information on how to build a DIY generator set. It is set up high to avoid bending, and provides plenty of space to work out how to best reject all the waste heat, for collection or disposal.

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Engine speed governing is simplified by using a Pierce mechanical governor, driven from the fan belt.

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Simple elbow connection for gas/air mix into throttle assembly. Gas/air mixer/condensate separator just showing on the left of the picture.

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A small temporary electrical load bank was set up to consume the electrical output, and facilitate engine response to variable loading

These chunky hardwood nuggets were the best average size for the wood we tested. They could be replaced with thick chips, but would need to be a minimum of 30x30x5-10mm.

Conifer blocks cut from the urban waste roadside rubbish collection. First cut to 50x50x12mm, the large flat surfaces created flow problems in the fuel hopper. Re cut to 50x25x12mm as shown in 20 litre pail, they worked fine. The wood in the pail amounts to
5 kg, and will do the same work as 1.6 liters of diesel. Therefore has the same value as diesel fuel, and it's cost is not exported out of the local economy.

The down side of urban waste wood is nails, and in a high temperature gasifier, act as a catalyst for ash to form clinker. Once the clinker begins to form, the natural movement within the char bed is disturbed, and the gas making equilibrium moves out of balance.

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Rarely seen as a separated solid from producer gas, these carbon blacks were collected from the gas/air mixer at the engine. They are a graphite structure and as such harmless to the engine, but if not removed, build up deposits in the inlet manifolds.

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When producer gas is hot, it carries water vapor, which in turn, carries dust and carbon blacks. This test flare displays the radiance created by carbon blacks, as the cooling system was pushed way past it's heat rejection capability.