This is covered in more detail in the second section. The constricted hearth, downdraft gasifier shown in Fig. It has been commercially manufactured under various names. A list of known manufacturers is here. But when World War II started, it took six to eight months before factory-made gasifiers were widely available.

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A wood gas generator is a gasification unit which converts timber or charcoal into wood gas , a syngas consisting of atmospheric nitrogen , carbon monoxide , hydrogen , traces of methane , and other gases, which - after cooling and filtering - can then be used to power an internal combustion engine or for other purposes.

Historically wood gas generators were often mounted on vehicles , but present studies and developments concentrate mostly on stationary plants. Gasification was an important and common technology during the 19th and early 20th century. Town gas produced from coal was widely used, mainly for lighting purposes. When stationary internal combustion engines based on the Otto cycle became available in the s, they began displacing steam engines as prime movers in many works requiring stationary motive power.

Adoption accelerated after the Otto engine's patent expired in The potential and practical applicability of gasification to internal combustion engines were well understood from the earliest days of their development.

In , Thaddeus S. Lowe developed and patented the water gas process by which large amounts of hydrogen gas could be generated for residential and commercial use in heating and lighting.

Unlike the common coal gas, or coke gas which was used in municipal service, this gas provided a more efficient heating fuel. During the late 19th century internal combustion engines were commonly fueled by town gas, and during the early 20th century many stationary engines switched to using producer gas created from coke which was substantially cheaper than town gas which was based on the distillation pyrolysis of more expensive coal.

During World War II gasoline was rationed and in short supply. Due to the lack of gasoline from petroleum, older people recalled how to build gasifiers for both wood and coal, and how to convert internal combustion engines to run on gaseous fuel, and wood gas generators were in active production.

In Great Britain, France, the United States and Germany, large numbers of such generators were constructed or improvised to convert wood and coal into fuel for vehicles. Commercial generators were in production before and after the war for use in special circumstances or in distressed economies.

Germany produced Gazogene units for vehicles including cars, trucks, artillery tractors and even tanks, to preserve the limited supplies of fuel.

Coal-based town gas production was generally displaced by petroleum-based gas and natural gas. However, Great Britain continued her use of coal-based town gas until the North Sea natural gas discoveries in the s and s. When oil prices rose there was renewed interest in wood gas generators. There was also an experimental device to use the Fischer-Tropsch process to convert wood gas to a diesel-like fuel. The Democratic People's Republic of Korea North Korea is also known to have trucks that run off of wood gas generators.

The trucks are common outside of Pyongyang and are in rural villages and smaller towns. These trucks are utilized due to sanctions placed on North Korea regarding imports of oil and gas. There is a rich literature on gas-works, town-gas, gas-generation, wood-gas, and producer gas, that is now in the public domain due to its age. Most successful wood gas generators in use in Europe and the United States are some variation of the earlier Imbert design.

Wood gas generators often use wood; however, charcoal can also be used as a fuel. It is denser and produces a cleaner gas without the tarry volatiles and excessive water content of wood. It is designed to be rapidly assembled in a true fuel crisis.

This simplified design has distinct benefits over the earlier European units such as easier refueling and construction but is less popular than the earlier Imbert design because of significant new problems, which include a lack of a fixed oxidization zone and allows the oxidization zone to creep to a larger area, causing a drop in temperature; a lower operating temperature leads to tar production and it lacks a true reduction zone further increasing this design's propensity to produce tar.

Tar in the wood gas stream is considered a dirty gas and tar will gum up a motor quickly, possibly leading to stuck valves and rings. A new design known as the Keith gasifier improves on the FEMA unit, incorporating extensive heat recovery and eliminating the tar problem.

The United Nations produced the FOA 72 document [13] with details about their wood gas generator design and construction, as does World Bank technical paper Wood gas generators have a number of advantages over use of petroleum fuels:. When not carefully designed and used, there exists considerable potential for injury or death due to wood gas containing a large percentage of poisonous carbon monoxide CO gas.

Wood gasifiers of proven design and thoroughly tested construction are considered safe to use outdoors, or in a partially enclosed space, for example, under a shelter open to the air on two sides; they may also be considered relatively safe to use in an extremely well ventilated e.

However, prudence must dictate that any sort of experimental wood gasifier design or new construction be thoroughly tested outdoors, and only outdoors, with a "buddy" at all times, and with constant vigilance for any sign of headache, drowsiness, or nausea, as these are the first symptoms of carbon monoxide poisoning.

In addition, mixtures of excessive quantities of air and gas should be avoided as this could lead to the deflagration explosion of the gas in question if a combustion source is present. Long-term storage of wood-gas, except through the use of a gasholder -type water-displacement apparatus, should not be attempted, due to the volatile elements present in the gas, which, if allowed to excessively precipitate, will condense in the storage vessel. In , an example of designing and constructing a working wood gas generator powered truck was shown on the National Geographic Channel's Planet Mechanics in the eighth episode, "Tree Powered Car".

In , another example of designing and constructing a working wood gas powered generator engine was in the TV series The Colony in the second episode of the first season "Power Struggle". Also used in the tenth episode "Exodus" to power an escape vehicle. A Mother Earth News article discussed and showed pictures of a wood gas powered engine installed in a pickup truck. Part of the team are now working on a more advanced design leaning towards top speed as opposed to range.

On the popular US radio program Car Talk , a caller in episode which aired on January 7, , and was subsequently named "20 Miles Per Woodchip" , described a wood gas generating vehicle he rode in as a boy during World War II in Germany. The hosts were not familiar with the technology, likely because it was never widely adopted in the US. On March 12, , on a season 2 episode of Doomsday Preppers , a wood gas generator is shown running a Ford truck and a house electric generator by prepper Scott Hunt on his multi-acre woodland property in South Carolina.

An article appeared in Mother Earth News in April featuring the Keith gasifier, showing pictures and talking with inventor Wayne Keith. In the BBC documentary Wartime Farm , Episode 5 aired October they built a coal gas powered ambulance according to the specifications of a gas powered vehicle. There are only a few companies that produce wood gasifier systems commercially. A list can be found here below. Since wood gas systems have the tendency of being rather large, most focus on stationary applications electricity production.

Some may be suitable for building into vehicles though. From Wikipedia, the free encyclopedia. East Front. LaFontaine, F. For example, searching for "Producer Gas", "Gas manufacture and works", or "Gas Generators" on Google Books will yield many complete books on the subject that can sate the appetite of one interested in the history of technology or serve the amateur experimenter well, even dated as they are.

David Bransby July 10, Drive On Wood. Retrieved David Bransby December 28, Biofuels Digest. Archived from the original on David Bransby September Auburn University. Bolton September 15, Birmingham News. Mother Earth News. Jalopnik Hidden categories: CS1 errors: dates All articles with unsourced statements Articles with unsourced statements from September Namespaces Article Talk.

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Wood gas generator

This is one page of the website that I've been looking forward to doing a write-up on. Although I'm still new to working with gasifiers I do have a few feathers under my hat that gave me some basic but solid knowledge on this topic since I've acquired some real world "hands on" experience with the construction and the operation of both the Imbert and the FEMA gasifiers plus I've read as much as I could on the topic even if some of the technical language was a bit fuzzy to me including watching every video out there I could find. A cleaner gas producer. A more robust gas producer. Much lower tar emissions due to it's design. Very little to no tar mess to be disposed of or dealt with. No concerns of the fire climbing up through the wood hopper due to the wood hopper being a sealed oxygen free fuel holding vessel.


Imbert Gasifier

The downdraught gasifier makes it possible to use wood as fuel and produce a gas with sufficiently low tar content to operate an internal combustion engine. There are other means of handling the tar problem but these may create their own problems. Fox example, use of charcoal as fuel involves a loss of energy and increases the risk of depletion of wood resources. Use of cleaning systems after the gasifier involves difficult waste disposal problems. Down-draught gasifiers being comparatively easy to build and operate, are likely to be the most appropriate for developing countries as a source of decentralized power supply to rural communities and industries. The conversion of solid fuel to gas in a down-draught gasifier and the design basis for such gasifiers will therefore be examined in more detail. It is possible to distinguish four separate zones in the gasifier, each of which is characterized by one important step in the process of converting the fuel to a combustible gas.


There were also many homemade units, which lasted about 20, miles while factory made systems operated fro anything up to , miles. Looking at the Imbert Gasifier below the upper part of the cylinder is the hopper that holds the chips or other wood material. When being used to produce gas this hopper needs to be filled every couple of hours or as needed. Although the Imbert gasifier has been the prototype downdraft gasifier, it has a number of disadvantages. The hearth constriction seriously limits the range of fuel shapes that can be gasified successfully.

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