DIY gas generator: how to make a homemade unit

Gas generator - apparatus for the production of gas from coal, firewood, wood waste and other materials. The generated fuel can replace the traditional hydrocarbon fuel - natural gas for home heating and gasoline for the car.

The main idea of ​​using such a unit is saving on fuel costs. The constant increase in the cost of gasoline, propane and methane makes domestic craftsmen look for alternative ways to produce fuel.

To make a gas generator with your own hands, you need to understand its structure and principle of operation.

We will explain how the conversion of solid fuel into a combustible gas takes place, we will designate the design features of the unit and give examples of self-assembly of simple devices. For better assimilation of information, we have supplemented the article with visual diagrams, photographs and video clips.

Gas generator: device and principle of operation

The gas generator is a device that converts liquid or solid fuel into a gaseous state for further combustion in order to generate heat.

Fuel options for generating plant

The fuel-powered or mining units have a more complex structure than models using different types of coal or firewood.

Therefore, it is the solid-fuel gas generators that are most often found - a blessing, the fuel for them is affordable and cheap.

As a solid fuel in a gas generator use:

• wood, lignite and coal;
• wood pellets from wood waste;
• straw, sawdust and firewood;
• peat briquettes, coke;
• husk sunflower seeds.

Particularly thrifty owners themselves harvested sawdust briquettes.

Gas generation is possible from all these types of fuel. The release of energy depends on calorific value of different types of fuel.

Moreover, the heat from the combustion of raw materials in the gas generator is obtained more than from the use of solid fuel in boilers. If the efficiency of the usual wood boiler varies between 60–70%, then for the gas-generating complex the indicator reaches 95%.

But here it is necessary to take into account one nuance. The boiler burns fuel to heat the water, and the gas generator only produces fuel. Without a heater, stove or engine, the sense from a homemade gas generator will be zero.

The resulting gas should immediately be used - accumulating it in any container is economically unprofitable. To do this, you will have to install additional equipment, depending on the power supply.

What happens inside the gas generator

The basis of the gas generator is the pyrolysis of solid fuel that occurs at high temperatures and low oxygen content in the furnace. Several chemical reactions take place at the same time inside the gas generating device.

Technologically, the process of generation of combustible gas is divided into three successive stages:

1. Thermal decomposition of fuel. The process takes place under conditions of oxygen deficiency, which is fed to the reactor only one third of that required for normal combustion.
2. Purification of the produced gas. In a cyclone (dry swirl filter) the gas cloud is filtered from volatile ash particles.
3. Cooling. The resulting gas mixture is cooled and subjected to additional purification from impurities.

In fact, in the unit as such of the gas generator, it is the first process that takes place - pyrolysis. All the rest is the preparation of the gas mixture for further combustion.

At the outlet of the gas generating plant, a combustible mixture of carbon monoxide, hydrogen, methane and other hydrocarbons is obtained.

Also, depending on the fuel used in the pyrolysis, water in the form of steam, oxygen, carbon dioxide and nitrogen are added to them in varying amounts. According to the principle described, they function and pyrolysis heating boilersdemonstrating high efficiency.

Features of work of various converters

Gas generators for the device and technology of internal processes are:

• straight;
• converted;
• horizontal.

They differ in points of air supply and the output of the generated gas.

Direct process flows when the air mass is pumped out from below and the output of the combustible mixture at the top of the structure.

Reversed option implies the supply of oxygen directly to the oxidation zone. However, it is the hottest in the gas generating device.

It is quite difficult to make an injection into it independently, therefore this principle of operation is applied only in industrial installations.

AT horizontal gas generator the outlet with gas is located directly above the grate in the zone of combining oxidation and reduction reactions. This design is the simplest in independent execution.

Advantages and disadvantages of gas generators

It will cost a factory-made domestic gas generator 1.5–2 times more expensive than a conventional solid fuel boiler. Is it worth spending on this "miracle technique"?

Among the advantages of using gas generators are:

• full burnout, loaded into the furnace, and the minimum amount of ash;
• relatively high efficiency when working together with ICE either gas boiler;
• wide range of solid fuels;
• ease of operation and no need to continuously monitor the operation of the unit;
• time interval between rebootsfireboxes - up to a day on the wood and up to a week on the corner;
• possibility of using undiluted wood - wet raw materials can be used only in some models of gas generators;
• environmental friendliness of the device - this device does not have an exhaust pipe, all the generated gas flows in a direct stream into the combustion chamber of the engine or boiler.

When using wet wood, the generator will work, but gas production will be reduced by 20–25%. The drop in productivity is due to the evaporation of natural moisture from wood.

This leads to a decrease in temperature in the furnace, which slows down the process of pyrolysis. It is best to thoroughly dry the logs before loading into the pyrolysis chamber. Industrial devices are fully automated, the fuel supply to them is produced by a screw from a nearby container.

A self-made gas generator is not happy with this autonomy, but it is also quite simple to use. It is necessary only from time to time to load it with fuel to the eyeballs.

There are fewer flaws in the gas generator, but they are:

• weak gas volume controllability - when the temperature in the furnace decreases, the pyrolysis stops and instead of the combustible gas mixture, a mixture of resins is formed at the outlet;
• cumbersome installation - even a homemade gas generator of average power of 10–15 kW occupies a rather large space;
• duration of kindling - before the reactor produces the first gas will take 20-30 minutes.

After “warming up” the generator stably produces a certain amount of gas mixture, which must be burned or thrown into the air. To make this unit with your own hands will require strong gas cylinders or thick steel, and this is a lot of money. But all this pays off the efficiency of the generator and the cheapness of the original fuel.

Some models of gas generators are equipped with an air blowing fan, while others are not. The first option allows you to increase the capacity of the installation, but it binds its power supply. If you need a small generator for cooking food in nature, then you can do with a compact unit without an air blower.

Most of the self-made gas-generating installations work through natural thrust.

To heat a private house will need more powerful and volatile device. However, in this case, it is worthwhile to take care of a backup electric generator, so that overnight in case of an accident on the network, you will not be left without power supply or without heating.

Work units homemade unit

To figure out how you can make a solid gas generator with your own hands, you must clearly represent its structure. Each element has its own purpose, even the absence of one of them is unacceptable.

Inside the case of a self-made gas generator should be present:

• a solid fuel tank at the top of the unit;
• pyrolysis chamber, where the process of smoldering;
• air distribution device with check valve;
• grate with ash;
• discharge pipe for the produced gas;
• cleaning filters.

In a home-made generator, a sufficiently high temperature is formed on the wood, therefore, stringent requirements are imposed on each of its elements. For the case, durable sheet steel is used, and all the parts inside are selected as heat-resistant as possible.

To ensure the tightness of the fuel loading hatch in the closed state, the lid will need a gasket. The cheapest material for this is asbestos. However, it is not harmless to human health, it is better to find in the store special heat-resistant pads based on silicones or silicates.

The body can be either cylindrical or rectangular. Often, to simplify the work takes a couple of cylinders for natural gas or iron barrels. One of the grates at the bottom of the firebox is welded “tightly”, and the second one is built in so that it can be moved. It is necessary to clean them from slag and ash.

The air distribution unit is located outside the enclosure. It provides the necessary amounts of oxygen to the furnace, but due to the non-return valve it does not release combustible gases from it.

Manufacturing technology of the gas generator

Independently make the gas-generating installation in several ways. The choice here depends on the availability of materials and the further use of the produced gas.

Option # 1: An example of the construction of the device on the corner

Consider an example of making useful homemade metal bucket with a lid. At first we will prepare the unit which will process gas received from installation in the electric power.

After preparing the consumer for the upcoming operation, it is possible to start building the gas generator directly.

A nozzle that removes gas from the installation must be provided with a filter, since in the process of combustion, coal emits a lot of fine mist and dust.

Having completed the process of building a homemade gas generator, you need to check it for operability.

Option # 2: Gas generator from two hundred liter barrels

For a barrel homemade gas generator will require a pair of tanks in 200 liters. One of them is inserted into the other two thirds.

The space formed below will be used as a combustion chamber, and the upper part will be ideal for a firewood or pellet bunker.

On the side, at the level of the pyrolysis section, the pipe with a section of 50 mm is welded for air injection, and closer to the lid, the exhaust pipe is welded. In the bottom of the inner barrel cut out the hole for the flow of fuel into the combustion chamber, and attached to the bottom of the outer door blowing.

It remains only to make the filters cleaning the gas mixture before transferring it to the boiler. To do this, you will need used fire extinguishers or pipe sections of similar size.

On top of them tightly closed, and the bottom of the conical welded nozzle, at the end of which there is a fitting for the removal of ash. Then a side pipe is cut in to supply the gas mixture for cleaning, and a tap for already filtered gas into the cover.

Further, in order to lower the temperature of the combustible gas, a cooling radiator is made of several pipes with a diameter of 10 cm. Between themselves they are connected by small nozzles.

For the final purification of gas install another filter with expanded clay, small metal washers or sawdust inside. It is permissible to use the latter material only on condition that the incoming gas has already cooled, otherwise it may lead to a fire.

From the gas cylinder will make a “stove”. Instructions for creating a primitive furnace are given in this article.

Option # 3: Homemade model for ICE

For a car or motorcycle, a homemade gas generator is made in a similar pattern. Only here it is necessary to reduce the size of the installation to a minimum. To carry a heavy machine with it is expensive, and it looks not very aesthetic.

To make it easier for yourself, for the automotive version of the generator it is best to take the cylinders from under the gas. The main thing is to make sure before welding that there is already no hint of the presence in the propane tank, otherwise a small explosion may occur. To do this, unscrew the cylinder valve and fill the container to the eye with water.

Initially, the automobile gas generator produces too hot gases. They must necessarily be cooled. Otherwise, when in contact with hot parts of the engine, they may spontaneously ignite. In addition, the heated gaseous fuel has a low density, because of which it will be simply problematic to burn it in the cylinders.

A self-made gas generator for a car can be mounted in the trunk or on a trailer.

The second method is preferable due to:

• ease of repair;
• opportunities to leave the gas generating unit in the garage;
• the presence of free space in the trunk;
• the possibility of using the installation for other needs than fuel supply in the internal combustion engine.

Do not be afraid of road bumps. When jumping on bumps solid fuel in the combustion chamber will be shaken, which will only contribute to its better mixing and burning.

Nuances of the work and operation of gas generators

It is important to remember that the gas produced by the installation is odorless and poisonous. If the welding of metal parts of the gas generator will be mistakes, then the trouble can not be avoided.

For the natural flow of air in the combustion chamber can be drilled around the circumference of the casing holes of 5 mm. All installation work and performance checks should be carried out in a well-ventilated workshop or on the street.

After ignition, the valve is covered to limit the flow of oxygen into the combustion chamber. In order for the homemade gas generator to work properly, you must correctly adjust the output of the resulting gas mixture and the supply of oxygen.

Before starting to make a gas generator, it is necessary to make engineering calculations in which take into account the area of ​​combustion and the type of fuel, as well as the required output power and the intended mode work.

Conclusions and useful video on the topic

How to use a charcoal gas generator as a fuel supplier for a small car:

A simple gas generator of propane cylinders:

The device of the wood gas generator:

The above methods are suitable for the independent production of an effective gas generator. But the models of this device, there are much more. Some of them are easier to make, others more difficult.

The main thing when assembling the unit is to pay maximum attention to the quality of welds, otherwise gas leaks and explosion may occur. If everything is done correctly, the gas generator will properly serve 10–15 years. And then the metal of the case will start to burn through, and you will have to do everything anew.

Do you have practical assembly skills or experience using a homemade gas generator? Please share your knowledge and ask questions about the topic of the article in the comments below.