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Here’s answers to Frequently Asked Questions.  If you do not find what you’re looking for, see also the GEK wiki and GEK forum.  If confusion persists, please contact us via the contact page.

1. What is the GEK? What is a Power Pallet?

The Gasifier Experimenter’s Kit (GEK) is a downdraft biomass gasifier that comes in a kit, allowing the home energy hacker to create syngas that can be used to run an engine, such as in a car or a generator for making electricity. The Power Pallet is a GEK kit with all top-of-the-line add-ons, mounted on a metal pallet, and precision-tuned to an industrial-grade engine/generator.

2. What does the GEK run on?

The best fuel for a downdraft gasifier is a chunky and dry, carbon dense biomass. Things like wood chips, chunks, nut shells, coconut shells. Anything from 0.5” to 1.5” chunks are ideal. Here’s a handy chart:

Fuel Type	Will it work?	How well?	Processing required	Issues
Hardwood Chips	Yes	Great	.5″ to 1.5″ chips, such as from a disk chipper
Softwood Chips	Yes	Great	.5″ to 1.5″ chips, such as from a disk chipper
Nut shells	Yes	Great	Perfectly suited as is	great void spaces!
Coffee Grounds	Yes	Fair	Must be pelletized	Possible issues with clogging or swelling.
Sawdust	Yes	Fair	Must be pelletized	Possible issues with clogging or swelling.
Corn Cobs	Yes	Fair		Depending on cob size they may need to be broken in half
Rice Husks	Under development		process under development	High silica content, small particle size
Straw or Husks	Under review		high silica and ash contents. Currently being researched as a fuel.
Algae	Under review		possible low tar content. Currently being researched as a fuel.
Manure	Yes	Fair	dried to 25% moisture	High availability. High mineral content could lead to slag.
Leather Dust	Under review			Currently being researched as a fuel.
Coconut Shell	Yes	Great	Must be broken into chunks
Coconut Husk	No			Too fibrous to move through the system. Could work better if a process is found.
Paper	No	Poor		A fluffy fuel. Insufficient density to move through system. Possible fuel in briquette form, more research needed.
Bamboo	under review	Poor		High silica & ash content causes jams on ash grate.
Palm Pressings	Under review			Under research as a fuel. Possible high energy density.
Sugar Bagasse	No	Poor		A fluffy fuel. Could work better if a preparation process is developed.
Corn Stover	No	Poor		High ash & silica content. Could work better if a preparation process is developed.
Poultry Litter	Yes	Poor	Must be dried and chunked	Issues with preparation. High slag. High availability.
Municipal Solid Waste	Yes	Poor	Must be dried and chunked	High availability. High mineral content could lead to slag.
Coal	No			The GEK is designed to run on waste biomass.
Trash	No			Certain trash produces highly toxic fumes!
Tires	No			The GEK is designed to run on waste biomass.

The fuel needs to fill bed in a manner which leaves void space between the chunks. The void space is where the gas passes, and where the combustion and cracking takes place in the hearth. If you put fine material in the gasifier, the bed will pack, stopping gas flow, and the correct conditions for tar cracking will not be established.

The perfect fuel is a 1” wood sphere. Such would have fabulous void space and wonderful mechanical flow characteristics. As most do not have large supplies of 1” sphere, we approximate. In general, a chunk of wood about 1″ on a side is ideal, for air flow and combustion.

We do a lot of testing on different fuels to see how they run. The formal tests and numbers are here. If you want to just see the clean air filter and no tar after days of running a genset, see here.

3.  Does the GEK produce clean tar free gas?

The GEK cannot promise perfect gas nor hassle free operation.  There are too many variables of fuel size, shape and moisture content, in combination the variables of the operator to guarantee specific results.  However, we know through our extensive experience, and you can confirm through the community of GEK users, that the GEK will produce very clean gas when operated as intended.  See here for a 4 day / 30 hour run report.  If you use our instructions, and accept our assistance, we’re confident we’ll get you making clean gas at without too much hassle.

The basic GEK comes with a variety of improvements on historic Imbert gasifiers units that will increase the liklihood of your success.  Add to these basics the Hot TOTTI waste heat recovery and recyling components, and range of success expands dramatically.  This heat augmentation system makes it possible for us to run the GEK down to 3hp or 1kw continuous without tar.  This is an impossibly low rate for a traditional non-heat augmented gasifier.

We like to say there is a “Triangle of Dependencies” for successful gasification: the operator, the fuel, and the machine.  The weakest link in this triangle is usually the operator.  To help newbie operators along, we’ve developed the equivalent of a “speedometer” and “tachmeter” to guide your operation. You can use this a formal set of numbers to read temp and pressure gauges and know when things are good (or bad) in your gasifier.

4. Will the GEK run my car, truck, generator, lawnmower, tractor, boat, etc?

The standard GEK level IV is delivered with an Imbert type downdraft reactor sized to run engines in the 5 – 40HP. The standard reduction bell and nozzle configuration will run 5-20hp engines. Changing these particulars can expand the gas rate to support up to 40hp engines, or a 20-25kw genset.

Most people like to start with small engines– Listers, China Diesels, Briggs and Stratten, Honda V-twins, 4cyl car engines, etc. But you can easily adjust nozzle size and position, as well as change out the reduction bell to an optional larger version to support larger gas flows. We find the GEK is large enough to run common 4cylinder engines in smaller cars. Here’s an elaboration on the basic GEK running a Honda Accord with a standard 1600cc 4 cyl engine.

5. How long will the GEK run on one hopper load?

It depends on how much gas you are producing and/or the amount of power you are making.  In general, the standard 30 gal open top hopper on the GEK is sized for 3-6 hour runs.   On the Power Pallet we use a stainless steel 55 gal open top hopper, which should last around 6-10 hours depending on your use situation.  The exact run time will also depend on your load amount, density of your feed stock, and the amount of moisture in it.  For more detailed calculations, see number 12 below.

6. How long does it take to get one?

We are experiencing strong global demand for our gasifier Power Pallets. These are custom built to your specifications (kW capacity, phase, Hz, Voltage, etc ) and it’s a very complex endeavor. We strive to turn these around as quickly as possible and we make improvements in our manufacturing process daily. We ask that you verify production time when placing an order.

GEK Level IV and GEK TOTTI units have shorter production times, a matter of weeks, inquire when placing your order.
GEK Level III’s ship within 3-5 business days of receiving an order.

7. How much will it cost to deliver?

Shipping costs will vary widely for less common destinations. Surface shipping is also available for increased savings with a longer delivery time. Shipping costs of the GEK Level III, IV are significantly lower. Contact us for a fixed quote.

8. What are the maintenance requirements?

We designed the Power Pallet around a single operator’s 6 to 10 hour run. The assumption is that they will check the filter, the engine filter, the engine oil, the radiator fluid, and the ash grate at this time. The PCU provides automation of many features that would otherwise need to be adjusted by the operator.

9. How long will it last?

The Kubota’s published lifespan is 10,000 hours at 3600 rpm. Our distributor has multiple units that have been operating continuously in excess of 17,000 hours. We expect the GEK, with its fewer moving parts, to last longer than the Kubota. Any part that could wear out, and any part that comes in contact with the combustion zone, is easily and cheaply replaced as a consumable.

10. What kind of generator would you recommend?

Here’s a detailed exploration of what one wants/needs for a good producer gas genset, and a full inventory of options you might build or buy.  This documentation is mostly from the era of our exploring the options for the Power Pallet.  After going through everything from Listers to China diesels, Briggs and Strattons to Hondas, we’ve settled on the specifics seen here for the current Power Pallet.

11. Can I use the GEK to  run a diesel engine?

Yes, you can run a diesel on wood gas in dual fuel mode.  A little liquid fuel is still used for the pilot ignition.  But about 90% of the fuel can be wood gas fumigated into the air intake of the engine.  See here for more details.

12. Can the gas be compressed and stored for use later? If so, how?

Technically it can, but the economic returns and logistical hassles make it not really a good idea. The energy density is about 1/8^th that of natural gas.  It takes a very large amount of energy and/or very large storage vessels to store any reasonable amount.  Pressurization and storage of natural gas is already a dubious proposition.  Now make that 8x worse.  Also, it is easy to get some oxygen mixed in with your made gas.  Mixing oxygen and fuel under pressure is a bad idea. You’ll be much better off generating electricity right away, and storing it for later use in a battery.

 

13. Will this be something I can use to feed energy back into the grid?

Absolutely. However, if you use the energy produced to offset your own consumption then you are saving money at the retail rate rather than at the wholesale rate the utility purchases it at. We have our gasifier systems in 24 different countries around the world, and we have found that each country – and sometimes each state or region in the country – have different requirements for connecting to the grid. Begin by researching the legalities in your area.

There are several challenges to be overcome in connecting any power source to the grid, involving greatly varying investment, and these are discussed in greater detail here:

http://wiki.gekgasifier.com/w/page/14895893/How-to-Grid-Tie

APL can ship your genhead configured for your local power needs, at 120v or 240v, or 50 hz or 60hz.

 

14. I want a bigger GEK to run a V-8 engine.  Can you make me one?

This is easy in principle. The GEK Imbert is designed on a set of formal ratios for all vessel sizes and internal relationships, as well as the plumbing sizes for air in and gas out.  You can see the steps for GEK upsizing here.  The resulting new sheetmetal dimensions are easy to cut via the CAD design and CNC cutting method that produces the units currently.

In practice, however, the details of sourcing, logistics, information support, and unit testing make supporting multiple sizes simultaneously a challenge to our progress on the fundamentals.  Thus we have tried to stay with the size the greatest number of users/developers want, and thereby optimize the potential for collaboration engineering and development on top of a common base.  All the details we work out on the small units will transfer to larger units down the road.  We will just get there faster by not forking the road from the beginning.

Nonetheless, if you have a more ambitious project and are interested in developing a larger GEK installation, write us and we can discuss the options.

15. All Stainless steel gasifiers look hot!  Can I get the GEK in stainless?

Yes. We build GEKs in a motivated combination of stainless alloys and mild steels.  Exotics are used only where required, thus minimizing price while maximizing longevity.  For exceptional use situations, all stainless versions of the GEK are also available.  Write us for details on the pricing.

16. Can I heat my house, cabin, garage, with the GEK?
(or)
Can I use the gas from the GEK in my existing boiler or water heater?

Yes the GEK will produce a flammable gaseous fuel that you can simple burn for heating.  However, you will need to retrofit your heater/boiler with a new combustor that will properly burn producer gas.  You can’t just put the producer gas into the same fuel line, as the mixture ratio of wood gas is very different than propane or natural gas.  This retrofit or rebuild might be easy or difficult depending on your specific equipment and your building skills.

17. How much wood do I need to make (insert HP) or (insert KW)?

1 gal of gasoline or diesel will make about 15HP of shaft power for one hour.  if driving a genset, this will produce about 10KWe.

1 gal of gasoline or diesel is equivalent to about 20lbs of biomass through a gasifier.

1 ton of biomass to power through a gasifier-engine system is equal to about 100gal of liquid fuel in a genset, or 1MW of electricity.

Thus, the main rule of thumb to remember:
1 kg of biomass ~ 2lbs biomass ~ 2m3/h woodgas ~ 1HP ~ 0.75KW

See here for the details

18. How much wood do I need to drive my car?

Here’s how to approximate how much power your vehicle requires at cruise?

60MPG = 1gal/hr or 15HP for one hour
30MPG = 2gal/hr or 30HP for one hour
15MPG = 4gal/hr or 60HP for one hour

Remember that wood gas contains carbon monoxide and thus should never be used indoors.  It is not ok to run a wood gas heater, wood stove, boiler or otherwise inside an enclosed building, with or without ventilation.

19. Is an air compressor needed at startup?

The GEK Level IV kit is currently shipping with a venturi ejector that runs off of an air compressor to create the downdraft needed for startup. We are experimenting with a 12 volt fan that runs off the engine’s battery and will offer it as an option.

20. If I get a GEK, will it become outdated? Will you continue to support old versions?

We consider GEK customers to be entering into a relationship with us and the larger biomass-to-power community. We will support all products we sell indefinitely. We commonly send newly developed components to existing customers. The modular design allows any unit to be upgraded to our top model at any future time.
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21. What is the flow rate/ fuel consumption / thermal output?

On average the 10kW Power Pallet consumes a full hopper load every 6 to 10 hours. This rate will vary greatly with the load placed upon the engine. You can approximate 12kg or 26 lbs of biomass per hour of operation. The result will be 200,000-300,000 BTUs per hour in the syngas, which at the 20% efficiency of an IC engine comes out to 10kWe. Note that a portion of the remaining energy is recycled back into the Pyrocoil. After producing electricity we estimate that there are 30,000 – 100,000 BTUs available for your CHP use in the engine exhaust and coolant.