Wood gas generator

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Click on Photo for Gasification Video...

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.

History

Origins

Gasification had been an important and common technology which was widely used to generate Town gas from coal mainly for lighting purposes during the 19th and early 20th century. When the first stationary internal combustion engines based on the Otto cycle became available in the 1870s, 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 1886. The potential and practical applicability of gasification to internal combustion engines were well-understood from the earliest days of their development.
In 1873, Thaddeus S. C. 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 sometimes 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.
In about 1920 French inventor Georges Imbert created the "Imbert" downdraft generator.
During World War II gasoline was rationed and in short supply in Great Britain, United States and Germany large numbers of such generators were constructed or even 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.

Post WWII

Saab 99 running on wood gas in Finland. The gas generator is on the trailer.

The US Federal Emergency Management Agency (FEMA) published a book in March 1989 describing how to build a gas generator in an emergency when oil was not available.
A project about the energy future of Europe was begun in 2005 in Güssing, Austria with contribution of European Union research furtherance. The project consisted of a power plant with a wood gas generator and a gas engine to convert the wood gas into 2 MW electric power and 4.5 MW heat. At the wood gas power plant are also two containers for experiments with wood gas. In one container is an experiment to convert wood gas, using the Fischer-Tropsch process, to a diesel-like fuel. By October 2005, it was possible to convert 5 kg wood into 1 litre fuel.

Design

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.^[1]
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.
The FEMA unit from 1989 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. Testing at Auburn University has shown it to be 37% more efficient than running gasoline.^[2] This system set the world speed record for biomass powered vehicles^[3] and has made several cross country tours.^[4]^[5]
The United Nations produced the FOA 72 document with details about their wood gas generator design and construction, as does World Bank technical paper 296.^[6]^[7]

Advantages

Wood gas generators have a number of advantages over use of petroleum fuels:

They can be used to run internal-combustion engines (or even gas turbines, for maximal efficiency) using wood, a renewable resource, and in the absence of petroleum or natural gas, for example, during a fuel shortage.
They have a closed carbon cycle, contribute less to global warming, and are sustainable in nature.
They can be relatively easily fabricated in a crisis using materials on hand.
They are far cleaner burning than, say, a wood fire or even a gasoline-powered engine is (without emissions controls), producing little if any soot.
When used in a stationary design, they reach their true potential, as they are feasible to use in small combined heat and power scenarios (with heat recovery from the wood gas producer, and possibly the engine/generator, for example, to heat water for hydronic heating), even in industrialized countries, even during good economic times, provided that a sufficient supply of wood is attainable. Larger-scale installations can reap even better efficiencies, and are useful for district heating as well.

Disadvantages

The disadvantages of wood gas generators are:

the large specific size
the relatively slow starting speed; the time to heat the initially cold batch of wood to the necessary temperature level can take many minutes and in bigger plants even hours until the designed power is reached.
a batch burning operation, that some designs feature, and that regularly interrupts the gas producing process.
the stop operation out of a high load level is difficult (for example the stop of the engine using the gas): the residual heat still produces gas, which for a certain time leaves the gasifier either without control, or has to be used in a burner
the primary combustible fuel-gas produced during gasification is carbon monoxide: it is an intentional fuel-product, and is subsequently burned to safe carbon dioxide in the engine (or other application) along with the other fuel-gases; however, continuous exposure to carbon-monoxide can be fatal to humans even in small to moderate concentrations.
the humidity of the wood (usually 15 to 20%) and the water vapor created by the O- and H-atoms of the dry wood itself (about 0.4 liters of water loaded with organic substances per kg of dry wood) condenses during the gas cooling and filtering procedure and yields a liquid (see also wood tar), which needs specific waste water treatment. This treatment requires about 25 to 35 % of the created wood gas energy.

Safety consideration

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.g. negative pressure) indoor area not connected to any indoor area used for sleeping, equipped with redundant (more than 1), completely independent, battery-powered, regularly tested carbon-monoxide detectors. 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. Under no circumstances should wood-gas ever be compressed to more than 15 pounds per square inch (1.0 bar) above ambient, as this may induce condensation of volatiles, as well as lead to the likelihood of severe injury or death due to carbon monoxide or deflagration if the vessel leaks or fails.[citation

Wood Burning Stoves

Contact:

Wood Stoves and Wood Burners

Homemade wood stoves can be as simple as setting up a windscreen and burning the wood inside it (pot set on stakes or rocks). More complex versions are elevated off the ground to protect your fire and ground, incorporate integrated pot stands and sometimes even have electric fans.

There are several commercial and many more homemade wood stoves out on the trail and the advantages are obvious.

Advantages include:

generally weigh a bit more than other stoves but since you don't have to carry fuel this system may be lighter than other systems for long trips
able to melt enormous amounts of snow without carrying huge amounts of fuel
cheap to make, free fuel
potential for unlimited hot water and even water purification
smoke may get rid or decrease the amount of bugs in your campsite
use as a heater to warm up cold bones on chilly evenings and brisk mornings
produce less overall pollution than other fuels (no drilling, refining, transporting, etc)
renewable energy source
a wood fire is magical

Disadvantages include:

weight, bulk
blackening of pots and everything your pot and stove touches in your pack
everything you hike with will smell like smoke
need to hunt for fuel at the end of the day or during your trek
dependence on availability of dry burnable wood
slow cook time
need to fiddle with the fire
knowledge of fire building required
potential to start forest fire in dry windy areas
may be banned in your hike area

Why is using a stove better than just starting a fire on bare earth? Wood stoves generally reflect a great deal of the heat back into the fire and keep it hot. It is easier to set a pot on a wood burning stove than it is to balance it over an open fire. You will need a fraction of the wood to cook up a meal in a stove compared to an open fire. Wood stoves also generally protect the fire and fuel from wet and/or cold earth. They may also be allowed where campfire aren't and can be environmentally friendly in that they don't use up as much of the forest for fuel, produce as much smoke as a campfire and if purposefully built, will not even burn the ground they are on (leave no trace).

Zip Stoves/Turbo Stoves

10oz Sierra Titanium Stove

ZZ manufacturing makes the well know Sierra Zip Ztove which is a self contained wood stove with a battery operated fan to keep the fire going. It weights over a pound (10 ounces for titanium version) plus the weight of the battery (AA or D cell). There are a number of ways to improve and/or lighten the steel version of the stove (see Links). Fancy folks can add a solar cell to recharge batteries and help power the fan during the day.

5.4oz Stove (including pot stand)

Homemade versions of this stove can be made from various sized tin cans, pots or sheet metal (such as aluminum flashing) and an electric fan (computer fans work well) with a power source. Air output to the stove can be controlled by adding variable resistors to your electrical circuit or by just moving an unattached fan further away from the stove opening.

Jerry Pepera's Zip Stove

Building your stove so that it is off the ground and placing the fan centered underneath it provides more equal distribution of forced air and protects the ground.

Made from 12oz Chicken and 26oz Decaf cans

Alternately, placing the fan on the side of the stove enables you to build a less complex stove without a bottom which should be easier to build, harder to break, and lighter.

Similar stoves include:

MAGH Smoke Burnger Stove

Making Your own pulsed air wood stove

Kettle/Chimney/Volcano Stoves

Chimney Kettle Parts

Chimney Kettle Setup

Chimney water heaters have been around for a long time. The Russians have their Samovar and the Irish, Brits and Aussies all have similar kettle designs. These incorporate a chimney that shoots up the middle of the kettle and out the top. The kettle is set on a fire plate/bowl and when the fire gets going, hot air rises up the chimney and out the top of the kettle, - forcing fresh air to be drawn into air inlet opening at the bottom of the fire pit, feeding the fire and keeping the flames hot. These are generally made of brass, tin or aluminum and depending on how they are sealed (welded/brazed, riveted, rolled, epoxied, good/bad quality, etc), determines if and how much they will leak.

19.2oz Kelly Kettle

Homemade versions of the chimney kettle can be difficult to make requiring a nontoxic high temperature sealer (is JB weld non-toxic when heated in drinking water?) and/or the equipment and know-how to weld/braze your material. Aluminum flashing works as does fitting together large aluminum cans for the outer wall with smaller ones for the chimney. Brass is nice, but can be heavy.

Collapsible Wood Stoves

Disassembled Fire-Spout 100

Collapsible wood burning stoves allow you to easily dismantle, flatten and pack away what would otherwise be a very bulky setup.

18oz Stainless Fire-Spout-Mini and 32oz Galvanized Fire-Spout 100

O.C.Outdoor's Fire-Spout is one of the few truly collapsible commercial wood burning stoves on the market.

520g Magic Stove

The Swiss Magic Stove is also a nice little stainless setup. Collapses to 4.5" x 5.9" x 0.4".

Nimblewill Nomad's Wood Burning Stove with optional front

Nimblewill Nomad's "Little Dandy" is a collapsible stove that can be made form steel, titanium or thick aluminum sheet. It can be heavy (11.5oz range) if you use heavy gauge steel (22GA) but flattens down nicely and is easily packable (although it will not fit in a small pot such as the Grease Pot unless you alter the dimensions). Galvanized steel is never recommended as it releases heavy metals into the air when heated. See the template page for templates.

If you are not up to making one of these yourself, Chris Randall will be happy to send you one from the UK for about US$25 plus shipping. According to Chris, the Kelly Kettle fits right on to of the Nomad without modification.

Calculated weight estimates for Nimblewill Nomad's Wood Burning Stove

(including optional front)

Stainless 22GA	11.7oz
Stainless 24GA	9.4oz
Stainless 26GA	7oz
Stainless 28GA	5.9oz
Stainless 30GA	4.7oz

Steel 22GA	11.4oz
Steel 24GA	9.1oz
Steel 26GA	6.8oz
Steel 28GA	5.7oz
Steel 30GA Side of solvent can 0.012"	4.6oz

Titanium 22GA	6.7oz
Titanium 24GA	5.3oz
Titanium 26GA	4.0oz
Titanium 28GA Thru-Hiker's 0.016"	3.3oz
Titanium 30GA	2.7oz

Can/Tube Stoves

14.8 oz Trailstove

Simpler stove designs are basically ventilated steel cans or tubes. The US$20 Trailstove comes with a hose and tube for blowing. There are a few commercial units made of steel or titanium - and homemade ones can generally be fabricated from cans, pots (such as light weight and expensive titanium pots), or metal sheet. Aluminum flashing may work for a few fire-ups but will burn after you get it hot enough. See our Potstand page for information and calculators that will help with design planning.

21.5oz Trekstov

More sophisticated versions have adjustable ventilation and are built sturdy (and heavy) for long term use. The MAGH Twister Stove/ in fact is a double walled vortex stove which uses centrifugal decomposition to mix smoke with air for a more complete burn.

Trimmed 26oz Coffee Can (3.5oz)

Simple homemade versions can be made from trimmed down tin cans with bottom ventilation (a church key or unibit works well for this). These wood burners may also double and pot stands for alcohol and/or solid fuel stoves.

Unibit - ideal for making or enlarging holes in thin metal

A slightly lighter, rustproof and much more expensive stove may be fabricated from a titanium pot.

WoodGas Stoves

Image modified from:

A Wood-Gas Stove for Developing Countries
T. B. Reed and Ronal Larson

If wood is heated up and gasified, it has the potential of burning more completely, efficiently and with little or no smoke and heavy pollutants. These stoves tend to be a bit more complex than a tin can with holes punched in it and therefore tend to weigh a bit more, but may make up for extra weigh if you are packing in wood pellets or where fuel is more scarce. For more information on wood gasification, check out Wood-Gas Stoves for Developing Countries and Testing and Modeling the Wood Gas Turbo Stove.

The picture above depicts a stove made from coffee cans and is more or less self-explanatory except for the "Gas Wick." The gas wick is a smaller diameter can suspended by wires inside the larger coffee can with its closed bottom up. The wick become very hot and draws gas and air up along its sides, and prevents air from going down the chimney.

It is also important to note that fuel is ignited from the top down for the gasification process to work.

Caveats

First - If you would like to use wood as a fuel you will need to be able to start a fire. The most important aspect of this is fire starting skill. Learn to start a fire. Here are some basic techniques-

Use small dry twigs or shavings to start and add bigger stuff on top
Pack everything tight, add liquid fuel and light
A fan, tube to blow through, or sleeping pad to wave back and forth may be necessary to get the fire red and hot

Second - You will need a flame or spark, preferably waterproof or in a waterproof container

Lighters
Matches
Magnesium and flint
Steel wool and 9V battery
Battery with wire or aluminum plate to heat up tinder or make a spark
Sparker - sparklite or other doodad
Magnifying glass to concentrate sunlight - can be made form ice or condom filled with water
Parabolic mirror - see Fire from a Can of Coke and a Chocolate Bar Part II
Wood Friction -
- Fire Saw (rubbing two sticks together)
- Fire Drill (Fire Bow Drill, Hand Drill, Fire Thong, Pump Drill, Fire Spindle, etc.)
- Fire Plough
Fire Piston - a good DIY project if you are looking for one
Chemical - potassium permanganate and glycerine or antifreeze or sugar

Third - You may need tinder and/or a fire starter, especially if you are likely to have wet or damp wood.

Vaseline soaked cotton (real cotton) balls in film canister
Bottle of liquid fuel such as kerosene or alcohol
Knife to make wood shavings and/or "fuzz sticks" (stick with curls carved on the sides)
Candles (melt wax on kindling)
Folded up wax paper
Cardboard, paper or cotton soaked in wax
Lint from dryer
Fuel tabs
Commercial fire starter sticks
Fire starter paste
Dry pine needles, leaves, grass, bark, small twigs, etc.
Finished pages from novel/guide book
Char cloth in waterproof container or bag
Soap coated steel wool
Frayed rope (not treated with fire retardant and made from plant fibers)
First Aid/Hygiene kit items - cotton dressings, Vaseline impregnated dressings, toiled paper, Q-tips, tampons, etc.
Shaved magnesium
gunpowder from bullet
small piece of plastic explosive

Fourth - Unless you are packing in wood and packing out ash, wood stoves are not entirely "leave no trace." Beware of uppity and/or extremist hikers and rangers who might frown on you burning up their wilderness. That and you might just be part of a real eco problem - depending on where you decide to use a wood stove.

Wood Properties

Beyond wood, many other biofuels may be burned. You can use agricultural waste, paper products, dried humanimal waste, coal, charcoal, manufactured fire logs, last year's fruitcake, etc.

Firewood Quality
Hard Woods
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Alder	Medium-Low	2506	Easy	Fair	Good	Moderate	Slight
Apple	High-Medium	4132	Difficult	Difficult	Excellent	Few	Excellent
Ash , Black	Medium	4132	Easy-Moderate	Fair-Difficult	Good-Excellent	Few	Slight
Ash, Green	High	3590	Easy-Moderate	Fair-Difficult	Good-Excellent	Few	Slight
Ash, White	High	3,689	Easy-Moderate	Fair-Difficult	Good-Excellent	Few	Slight
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Aspen, Bigtooth	Low	2439	Easy	Easy	Good	Few	Slight
Aspen, Quaking	Low	2373	Easy	Easy	Good	Few	Slight
Basswood	Low	2174	Easy	Easy	Poor	Few	Good
Beech	High	3757	Difficult	Difficult	Excellent	Few	Good
Beech, American	High	3793	Difficult	Difficult	Excellent	Few	Good
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Beech, Blue	High	3890	Difficult	Difficult	Excellent	Few	Good
Birch, White	Medium	3179	Easy	Easy	Good	Moderate	Slight
Birch, Sweet	Medium	4065	Easy	Easy	Good	Moderate	Slight
Birch, Gray	Medium	3179	Easy	Easy	Good	Moderate	Slight
Birch, Paper	Medium	3260	Easy	Easy	Good	Moderate	Slight
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Birch, Yellow	High-Medium	3723	Moderate	Easy	Good	Moderate	Slight
Birch, Black	High-Medium	3890	Moderate	Easy	Good	Moderate	Slight
Buckeye, Horsechestnut	Low	2235	Moderate		Poor	Few	Slight
Boxelder	Low	2797	Easy		Poor	Many	Slight
Butternut (white walnut)	Low	2440	Easy
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Catalpa	Low	2360	Difficult		Good	Few	Fair
Cherry, Black	Medium	2880	Easy	Difficult	Excellent	Few	Excellent
Cherry	Medium	3184	Easy	Difficult	Excellent	Few	Excellent
Chestnut	Low	2708	Easy			Many	Good
Coffeetree, Kentucky	High	3112	Moderate		Good	Few	Good
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Cottonwood	Low	2102	Easy	Easy	Good	Moderate	Slight
Dogwood	High	4331	Difficult	Good	Fair	Few
Elm, American	Medium	3116	Very Difficult	Fair	Good	Very Few	Fair
Elm, Rock	Medium	3860	Very Difficult	Fair	Good	Very Few	Fair
Elm, Siberian	Medium	3020	Very Difficult	Fair	Good	Very Few	Fair
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Elm, Slippery	Medium	3251	Very Difficult	Fair	Good	Very Few	Fair
Eucalyptus	Very High	4560
-Swamp yate			Difficult	Poor	Excellent	Few	Good
-Sugar gum			Difficult	Poor	Excellent	Few	Good
-Tasmanian blue gum			Fair	Fair	Good	Few	Good
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
-River red gum			Difficult	Poor	Excellent	Moderate	Good
-SA blue gum			Difficult	Poor	Excellent	Few	Good
Hackberry	High	3319	Easy		Good	Few	Slight
Hazel	High		Moderate	Moderate
Hawthorn	High		Moderate	Moderate
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Hickory, True	Very High	4,327	Moderate	Fair-Difficult	Excellent	Moderate	Excellent
Hickory, Mockernut	Very High	4332	Moderate	Fair-Difficult	Excellent	Moderate	Excellent
Hickory, Pignut	Very High	4332	Moderate	Fair-Difficult	Excellent	Moderate	Excellent
Hickory, Shagbark	Very High	4333	Moderate	Fair-Difficult	Excellent	Moderate	Excellent
Hickory, Shellbark	Very High	4195	Moderate	Fair-Difficult	Excellent	Moderate	Excellent
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Holly, American		3387	Difficult
Honeylocust	High	3832	Easy		Excellent	Few	Slight
Hophornbeam, Eastern		4266
Ironwood (Hornbeam)	Very High	4267	Very Difficult	Very Difficult	Excellent	Few
Laurel, California		3456
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Locust, Black	Very High	4470	Very Difficult	Difficult	Excellent	Very Few	Slight
Madrone	High	3925	Difficult	Difficult	Excellent	Very Few	Slight
Maple, Bigleaf	High-Medium	2980	Moderate	Fair-Difficult	Excellent	Few	Excellent
Maple, Silver	High-Medium	2981	Moderate	Fair-Difficult	Excellent	Few	Fair
Maple, Black	High-Medium	3523	Moderate	Fair-Difficult	Excellent	Few	Excellent
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Maple, Soft	High-Medium	2924	Moderate	Fair-Difficult	Excellent	Few	Excellent
Maple, Red	High-Medium	3318	Moderate	Fair-Difficult	Excellent	Few	Excellent
Maple, Sugar	High	3793	Moderate	Difficult	Excellent	Few	Excellent
Mesquite	Very High		Very Difficult	Very Difficult	Excellent	Few
Mulberry	Medium	3712	Easy		Excellent		Good
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Oak, Bur	High	3928	Easy	Difficult	Excellent	Few	Fair
Oak, Red	High	3680	Moderate	Difficult	Excellent	Few	Fair
Oak, White	Very High	4200	Moderate	Difficult	Excellent	Few	Excellent
Osage Orange	High	4728	Moderate		Excellent	Many	Excellent
Pecan	High		Moderate		Good	Few	Good
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Persimmon		4332	Moderate
Pine, Lodgepole	Low	2610	Easy	Easy	Fair	Moderate	Good
Poplar, Yellow (Tuliptree)	Low	2708	Easy	Easy	Fair	Moderate	Bitter
Sweet Gum	Medium	3115	Difficult	Fair	Fair	Few
Sycamore	Medium	3115	Difficult	Very Difficult	Good	Few	Good
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Walnut	High-Medium	3454	Moderate	Fair	Good	Few	Fair
Willow	Low	2438	Easy	Fair	Poor	Moderate	Slight

Soft Woods
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Cedar, White	Medium-Low	2100	Easy	Easy	Poor	Moderate	Excellent
Cedar, Eastern	Medium-Low	2981	Easy	Easy	Poor	Many	Excellent
Cedar, W. Red	Medium-Low	2100	Easy	Easy	Poor	Many	Excellent
Cypress	Medium	2844	Easy	Moderate		Few
Fir, Douglas	Medium	3049	Easy	Easy	Fair	Moderate	Slight
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Fir, Balsam	Low	2236	Easy	Easy	Fair	Moderate	Slight
Fir, Grand	Low	2371	Easy	Easy	Fair	Moderate	Slight
Fir, White	Low	2104	Easy	Easy	Fair	Moderate	Slight
Hemlock, Eastern	Medium-Low	2573	Easy	Easy	Poor	Many	Good
Hemlock, Western	Medium-Low	2847	Easy	Easy	Poor	Many	Good
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Juniper	Medium	3150	Medium		Poor	Many	Excellent
Larch, Western (Tamarack)	High-Medium	3318	Easy-Moderate	Easy-Fair	Fair	Many	Slight
Pine, Lodgepole	Low	2576	Easy	Easy	Fair	Moderate	Good
Pine, Ponderosa	Medium-Low	2573	Easy	Easy	Fair	Moderate	Good
Pine, E&W White	Medium-Low	2303	Easy	Easy	Fair	Moderate	Good
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Pine, Sugar	Low	2302	Easy	Easy	Fair	Moderate	Good
Pine, Yellow	High-Medium	2610	Easy	Easy	Fair	Moderate	Good
Pinon	High	3000	Easy			Many
Redwood, Old Growth	Medium	2573	Easy	Easy-Fair	Poor	Many	Slight
Redwood, Second Growth	Medium	2302	Easy	Easy-Fair	Poor	Many	Slight
Species	Heat	Weight*	Ease Of Splitting	Ease Of Starting	Coaling Qualities	Sparks	Fragrance
Spruce, Black	Low	2575	Easy	Easy	Poor	Few	Slight
Spruce, Engeiman	Low	2234	Easy	Easy	Poor	Few	Slight
Spruce, Norway	Low	2240	Moderate	Easy	Poor	Many	Slight
Spruce, Sitka	Low	2506	Easy		Poor		Slight
Yew	High		Difficult	Difficult			Good
*Weight - pound /cord - seasoned wood. Cord - stack 4' x 4' x 8' feet high (~85 ft³ with air space removed) Face cords - 4' x 8' x <4' (usually about 16" deep)

Alder: Poor heat output and short lasting. A low quality firewood. Produces nice charcoal that burn steady and is useful for homemade gunpowder.

Apple: Great fuel that bums slow and steady when dry, with little flame, sparking or spitting. It has a pleasing scent. It is easier to cut green. Great for cooking.

Ash: Considered one of the burning wood with steady flame and good heat output. It will bum when green, but not as well as when dry. Easily to saw and split.

Beech: Similar to ash, but only burns fair when green. If it has a fault, it may shoot embers out a long ways. It is easy to chop.

Birch: This has good heat output but burns quickly. The smell is also pleasant. It will burn unseasoned. Can cause gum deposits in chimney if used a lot. Rolled up pitch from bark makes a good firestarter and can be peeled from trees without damaging them.

Blackthorn: Burns slowly, with lots of heat and little smoke.

Cedar: This is a great wood that puts out a lot of lasting of heat. It produces a small flame, a nice scent, and lots of crackle and pop. Great splitting wood. Best when dry but small pieces can be burned unseasoned. Good for cooking.

Cherry: A slow burning wood with good heat output. Has a nice sent. Should be seasoned well. Slow to start.

Chestnut: A mediocre fuel that produces a small flame and weak heat output. It also shoots out ambers.

Douglas Fir: A poor fuel that produces little flame or heat.

Elder: A mediocre fuel that burns quickly without much heat output and tends to have thick acrid smoke. The Hag Goddess is know to reside in the Elder tree and burning it invites death. Probably best avoided.

Elm: A variable fuel (Dutch elm disease) with a high water content (140%) that may smoke violently and should be dried for two years for best results. You may need faster burning wood to get elm going. A large log set on the fire before bed will burn till morn. Splitting can be difficult and should be done early on.

Eucalyptus: A fast burning wood with a pleasant smell and no spitting. It is full of sap and oils when fresh and can start a chimney fire if burned unseasoned. The stringy wood fiber may be hard to split and one option is to slice it into rings and allow to season and self split. The gum from the tree produces a fresh medicinal smell on burned which may not be the best for cooking with.

Hawthorn: Good firewood. Burns hot and slow.

Hazel: An excellent fast burning fuel but tends to burn up a bit faster than most other hard woods. Allow to season.

Holly: A good firewood that will burn when green, but best if dried a year. It is fast burning with a bright flame but little heat.

Hornbeam: Burns almost as good as beech with a hot slow burning fire.

Horse Chestnut: A low quality firewood with a good flame and heating power but spits a lot.

Laburnum: Completely poisonous tree with acrid smoke that taints food and is best never used.

Larch: Crackly, scented, and fairly good for heat. It needs to be seasoned well and forms an oily soot in chimneys.

Laurel: Produces a brilliant flame.

Lime: A poor quality fuel with dull flame. Good for carving

Maple: A good firewood.

Oak: Oak has a sparse flame and the smoke is acrid if not seasoned for two years. Dry old oak is excellent for heat, burning slowly and steadily until whole log collapses into cigar-like ash.

Pear: Burns with good heat, good scent and no spitting. Needs to be seasoned well.

Pine: Bums with a splendid flame, but apt to spit. Needs to be seasoned well and is another oily soot in chimney wood. Smells great and its resinous wood makes great kindling.

Plane: Burns pleasantly, but is apt to throw sparks if very dry.

Plum: Wood provides good heat with a nice aromatic sent.

Poplar: A terrible fuel that doesn't burn well and produces a black choking smoke even when seasoned.

Rowan: A good firewood that burns hot and slow.

Rhododendron: Old thick and tough stems burn well.

Robinia (Acacia): Burns slowly, with good heat, but with acrid smoke.

Spruce: A poor firewood that burns too quickly and with too many sparks.

Sycamore: Burns with a good flame, with moderate heat. Useless green.

Sweet Chestnut: Burns when seasoned but tends to spits continuously and excessively.

Thorn: One of the best firewood. Burns slowly, with great heat and little smoke.

Walnut: Low to good value to burning. It a nice aromatic scent.

Wellingtonia: Poor for use as a firewood.

Willow: A poor fire wood that must be dry to use. Even when seasoned, it burns slowly, with little flame. Apt to spark.

Yew: This burns slowly, with fierce heat. The scent is pleasant. Another carving favorite. Note that every part of this plant, except for the fruit contains poisonous taxines. Death to livestock after ingestion of this plant is well documented and here are reported cases of suicides from ingestion of leaves. Sawdust is dangerous if ingested or inhaled. The Romans reported death after ingestion of wine stored in Yew vessels, yet Yew cups, bowls and plates are still very popular - not that this makes them any less poisonous. Taxines are carried in smoke and the safety of using this wood for cooking or heat is questionable.

Self Reliant Network

Monday, April 23, 2012

Wood gas is "Gasification"