How to make a wood gas generator with your own hands: homemade products using wood and sawdust

Over thousands of years of history, humanity has learned to extract oil and gas, invented electricity, uses wind and solar energy, but still burns wood in furnaces. Firewood, sawdust, old wood, waste from wood processing enterprises - all this can be used if you make a wood-burning gas generator with your own hands.

Many craftsmen successfully use this device for the home and even for the car. If you are interested in this topic, or have an idea to make a generator yourself, we will tell you how to implement it in practice.

In our material we will talk about the principle of operation of a wood-burning gas generator, the advantages and disadvantages of such a system, as well as how to assemble such a device yourself.

Operating principle of wood gas generators

Burning wood quickly in the open air produces mainly some useful heat. But wood behaves completely differently under the so-called pyrolysis combustion, i.e. when burning in the presence of very little oxygen.

In such a situation, it is not so much combustion that is observed, but rather smoldering of the wood. And the useful product of this process is not heat, but flammable gas.

Gas generators were once actively used as a fuel supplier for cars. And now you can occasionally find cars that run on the gas they produce:

When wood burns slowly, the output is a mixture containing the following products:

• methane (CH₄);
• hydrogen (H₂);
• carbon monoxide (aka CO or carbon monoxide);
• various limiting carbohydrates;
• carbon dioxide (CO₂);
• oxygen (O₂);
• nitrogen (N);
• water vapor

Only some of these ingredients are flammable gases; the rest are contaminants or non-flammable ballast that are best disposed of. Therefore, it is necessary not only to burn the wood in a special installation, but also to purify the result, and also to cool the resulting gas mixture.

In industrial production conditions, this process includes the following steps:

1. Solid fuel combustion in the presence of a small (about 35% of normal) amount of oxygen.
2. Primary rough cleaning, i.e. separation of volatile particles in a cyclone vortex filter.
3. Secondary coarse cleaning, in which the gas is purified using a water filter, a so-called scrubber-purifier is used.

Homemade devices for home use look simpler and take up less space, but the principle of their operation, as well as the design, are very similar. Before starting the manufacture of such a device, you need to think everything through carefully, and also draw up or find a design for the unit.

This diagram allows you to understand the structure of a wood gas generator: firewood is loaded from above, enters the combustion chamber, where a small amount of air is pumped, and where the process of slow combustion of fuel and the release of flammable gas occurs

There are many recommendations on the Internet on how to make a homemade wood gas generator. Some of them are equipped with drawings that are quite realistic for implementation.

Masters who have already managed to carry out this fascinating process to some extent note that it can take a lot of time and effort. It may be necessary to perform more than one alteration and carry out a number of experiments in order to obtain a unit with acceptable characteristics.

This diagram, which shows the operating principle of an industrial gas generator, allows you to get an idea of ​​the individual elements of a household gas generator

Advantages and disadvantages of the system

Gas generators are extremely easy to use. If the unit is made correctly, in compliance with all safety requirements, fuel can be loaded into it very rarely. For example, you can load firewood into the chamber only once a day, and if charcoal is used as fuel, once a week will be enough.

Industrial models of household wood gas generators are extremely convenient and safe, but the cost of such a device is usually very high

But this applies, rather, to industrially manufactured devices. Of course, work homemade gas generator should be carefully monitored. The temperature of the hot gas can be very high, and the risk of fire also increases significantly.

Wood is an affordable material. You can feed firewood, wood chips, and pressed sawdust, and any waste from the wood industry, and cellulose-containing materials. Dry and light charcoal is ideal as fuel. If the size of the bunker allows, you can load firewood into it even without preliminary chopping, entirely.

Almost any material containing cellulose is suitable for combustion in a gas generator, but it is important not to forget about the acceptable level of moisture content of such fuel in order to increase the efficiency of the device

The product obtained as a result of combustion, flammable gas, can be used to solve various problems: heating a house, operating a car’s internal combustion engine, even generating electricity. But it’s worth remembering the “cons” of this useful device.

To begin with, an industrial model of a gas generator, reliable, safe and convenient, is quite expensive. Not every home or cottage owner can afford such a unit. But creating a homemade gas generator, even from scrap materials, can cost a pretty penny.

It is not always possible to use any available materials for it. All parts of the unit must be very durable and able to withstand high temperatures. You will definitely need a welding machine, as well as skills to work with it. The metal will have to be cut and welded.

The fuel for the wood gasifier must be of a size and configuration that will allow it to move freely down the hopper to the combustion chamber

When calculating how much it will cost to create a homemade sawdust gas generator, you should also take into account consumables. You will need cast iron to create the grate; it is quite possible that you will have to find or buy a special spring to make the lid.

Heat-resistant gaskets are also needed for hatches, for connecting individual elements of the device, etc. Before making a gas generator, you need to carefully calculate everything.

Another cost item for a gas generator is electricity, which is necessary to force air into the combustion chamber. If for some reason the power is cut off, the gas generator will not be able to operate.

This situation is unacceptable, since a decrease in combustion temperature can lead to contamination of the device with tar. As a result, you will have to stop the process, clean the gas generator, and then start it again.

Although it seems that you can load the gas generator with almost any fuel, you should still remember that it must gradually, as it burns, fall down the bunker. Therefore, firewood for the generator should be prepared by cutting it into elements of more or less equal size.

Making a device yourself

First you need to decide for what purpose the gas generator will be made: for the home or for the car. In the latter case, priority is given to low weight and compact dimensions. The best material for a car gas generator is stainless steel, expensive, but durable and lightweight.But for the home they make a large device from scrap materials, which are easier to find and cheaper.

Let's look at an example of manufacturing a gas generator to provide fuel for a motorcycle:

To supply gaseous fuel to a gasoline engine, it must be cooled, cleaned and mixed with air in suitable proportions. To do this, the unit must be equipped with an ignition fan, a cyclone, a filter, a mixer and a cooler.

All that remains is to supplement the homemade gas generator with devices that ensure normal operation and resolve issues with installing it on a motorcycle with a sidecar.

Of course, the closer the size and configuration of a homemade gas generator to an industrial model, the more efficient the device will be. Making an exact copy of a factory-made gas generator at home is difficult, and not necessary.

It’s easier to copy a ready-made homemade unit by asking acquaintances, friends for it, or even simply using information on the Internet.

First, the main components of the gas generator are manufactured, then they are assembled into one whole device. To make such a device, you need to prepare the following elements:

1. Frame.
2. Fuel bunker.
3. Combustion chamber.
4. The neck of the combustion chamber.
5. Air distribution unit.
6. Filter unit.
7. Combustion chamber pipe.
8. Grate, doors and other similar elements.

The housing, sometimes called a fill chamber, can be either cylindrical or cubic in shape. Therefore, the craftsman has two options for its manufacture: use a suitable metal container, slightly modifying it, or make the case “from scratch” from a corner and sheet metal.

To make a homemade gas generator, you can use available materials, for example, a metal barrel, old gas cylinders, a fire extinguisher body, etc.

A bunker for solid fuel is made in the same way, that is, also from a metal sheet and a corner. Later, the hopper is fixed inside the housing, so its dimensions must be appropriate. However, sometimes it is easier to turn part of the gas generator housing into a bunker. To do this, part of the space is separated using metal plates.

The material suitable for the inside of a wood-burning gas generator is low carbon steel. The housing should be covered with a tight-fitting lid. Sealing is an important condition for the correct operation of the generator, since it is in this way that a limited amount of oxygen is supplied.

A homemade gas generator is a fairly heavy device; care should be taken to ensure its stability. To do this, strong legs are welded to the bottom of the body. The lid through which fuel is loaded deserves special attention.

Sometimes it can be heavy and it’s not easy to lift it yourself. To solve the problem, you can use a special shock absorber spring.

The combustion chamber will require special heat-resistant steel, since this is where the fuel burns at very high temperatures.However, for these purposes you can successfully use an empty household gas cylinder. Both a new container and a used one will do.

If the gas cylinder for the manufacture of a household gas generator has previously been used, it is better to fill it with water before starting welding work. This will prevent possible combustion of residual gas.

The metal neck of the combustion chamber, in which another important process—resin cracking—is carried out, should be separated from the other elements with special heat-resistant gaskets. Asbestos is considered a completely suitable material for this, but it is better to use more modern and safe materials.

The air distribution unit is connected to the structure using a fitting, next to which a check valve is installed. The task of this element is to regulate the flow of air to the fuel and prevent leakage of the resulting combustible gas, for which the creation of the generator was started.

Between the air distribution box and the middle part of the combustion chamber there must be special calibration holes-tuyeres. After the combustion chamber, a filter system is installed to clean the resulting gas mixture from contaminants. The grate is designed to clean the combustion chamber.

It is usually made of cast iron. To facilitate the cleaning process, the middle part of the grate can be made movable or removable. The doors provide access to various sections of the gas generator and are used for loading firewood, cleaning the combustion chamber, etc. Of course, all such doors must be airtight and sealed with heat-resistant gaskets.

A pipe is mounted below, through which the resulting gas mixture enters the filter unit and then into the cooler.To make a small cyclone filter, you can use the body of an old fire extinguisher or another metal container of a suitable size and configuration.

This diagram clearly demonstrates the design and operating principle of a cyclonic cleaning filter. With its help, you can perform primary purification of the gas obtained as a result of the operation of the gas generator

It works this way: contaminated hot gas is pumped into the upper part of the cyclone. Then, in the round housing, it begins to rotate. Under the influence of centrifugal forces, particles of contaminants move to the lower part of the device and leave it through the discharge opening. The purified gas exits through another hole at the top of the filter.

At home, you can use a regular radiator as a cooler or make a special coil. Hot gas moves along such a long structure and gradually cools down. If desired, water cooling can be arranged.

It is believed that a household gas generator is capable of “digesting” wood of any moisture content, even 50%, which is typical for a freshly cut tree. In practice, it turns out that the higher the fuel moisture, the lower the efficiency of the gas generator. It is not recommended to load the device with fuel whose humidity exceeds 20%.

A small modification of the device will correct the situation. A ring gas pipeline should be drawn from the combustion chamber nozzle, placing it in the space between the walls of the housing and the outside of the loading chamber.

As a result, part of the thermal energy will be transferred to the fuel, which will reduce its moisture content. In addition, cooling will take less time and the generator efficiency will increase.

Valuable information on gas generators

Sometimes the expectations of private home owners who are thinking about purchasing or making a gas generator themselves turn out to be too rosy compared to the real situation.

There is an opinion that the efficiency of a gas generator, which is about 95%, significantly exceeds the efficiency of a conventional floor-standing gas boiler, which reaches 60-70%. These figures are generally correct, but it is incorrect to compare them.

In the manufacture of a homemade gas generator, used gas cylinders, cans, kitchen utensils, etc. are used. The practically free device economically consumes not the most expensive fuel with fairly high performance

The first indicator reflects the efficiency of production of combustible gas, and the second - the amount of heat obtained during operation of the boiler. In both cases, wood burns, but the result of this process is qualitatively different. If in the future the combustible gas obtained by pyrolysis combustion of wood is used to heat a home, such a comparison can be made.

It is also worth remembering that homemade gas generators, although they can work with high efficiency, are rarely as effective as industrial models. This point should be taken into account at the stage of designing the unit and calculating the cost of the project and its expected efficiency.

If the need to create a gas generator is due only to the desire to improve the heating system at home, you should pay attention to a similar device - pyrolysis boiler, which works on very similar principles.Its main difference from a gas generator is that the resulting gas is immediately burned, and the resulting energy is used to heat the coolant in the home heating system.

In such a device, an additional combustion chamber is installed, into which it is necessary to organize a separate air supply. If you need to heat the house using a gas generator, you will need more choose a convector for heating. This will increase the cost of upgrading or installing heating. It is necessary to calculate whether in this case the game is worth the candle?

An important point is proper maintenance of the gas generator during its operation. Advertising claims that this is a universal device in which everything burns: from sawdust to freshly cut wood.

But the advertisement is silent about the fact that when loading wet raw materials, the amount of combustible gas produced can be reduced by 25% or more.

The best fuel for a household gas generator is charcoal. When burning it, too much energy is not spent on evaporating excess moisture, which allows you to obtain the maximum amount of combustible gas

The optimal fuel for a gas generator, according to experts, is charcoal. When it burns, a minimal amount of energy is consumed to evaporate moisture, which allows the pyrolysis process to be accelerated.

Vehicle owners can count on a gas generator not only for heating, but also for the operation of their vehicle. Indeed, in Europe, many motorists have quite successfully adapted their vehicles to run on wood. But most often these are compact and durable devices made of thin and durable stainless steel.

The cost of such units, even those made independently, is not at all small. In Russian realities, gas generators for cars are made from improvised materials and installed on trucks.

The effect of their operation is low; usually the presence of such a unit is accompanied by such phenomena as prolonged ignition, the need to constantly operate the engine at high or medium speeds, which contributes to its rapid wear.

For a car, it is best to use a high-quality gas generator made of durable stainless steel, having a relatively light weight and compact dimensions.

An interesting option for using a gas generator in private households is the use of combustible gas for a home power plant. Such a project is being implemented using a diesel internal combustion engine.

Conclusions and useful video on the topic

This video demonstrates the process of operation of a homemade gas generator:

Here is an interesting experience on creating a homemade gas generator, taking into account the mistakes made:

This is a variant of a compact gas generator designed for installation on a vehicle:

Making a viable gas generator with your own hands is not so easy. Most often, such units are made for cars, but they are also quite effective in homes. A skilled craftsman who is not afraid of difficulties and is ready to experiment is fully capable of this task.

If, while reading the information, you have questions or have recommendations for assembling a wood-burning gas generator yourself, please leave your comments below.