What is syngas (wood gas) and why is it key to a modern energy sector?

Many of you are familiar with the process of biomass gasification, but very few know exactly what its end product is and what potential it has. The result of the thermochemical conversion of carbonaceous material (such as wood chips) is a high-calorific synthetic gas, known by the abbreviation ‘syngas’, or more commonly in this country as ‘wood gas’.

What is wood gas made of?

Syngas is not a single specific substance, but a mixture of gases, the composition of which may vary depending on the material and technology used. Its main and most important energy components are:

Hydrogen (H₂)
Carbon monoxide (CO)

In addition to these, the gas also contains, to a lesser extent, methane (CH₄), carbon dioxide (CO₂), water vapour, nitrogen (N₂) and other hydrocarbons. Under specific conditions, impurities such as tars, hydrogen sulphide (H₂S) or ammonia (NH₃) may also form in the gas.

Where is syngas used?

Thanks to its gaseous form, syngas is an exceptionally versatile energy carrier. Its main areas of application include:

1. Heat and electricity generation: Gas is burnt in gas engines, turbines or steam cycles.

2. Chemical industry: It is used as a raw material for the production of synthetic fuels (e.g. methanol, ethanol) via the Fischer-Tropsch synthesis.

3. Source of pure hydrogen: High-purity hydrogen, suitable for use in fuel cells, for example, can be separated from syngas.

Why is gas purification so crucial?

Raw gas straight from the reactor is not suitable for immediate use in engines. This is because it contains impurities, in particular tar, dust particles and acidic components (HCl, HF).

Gas purification is essential, as these impurities could damage downstream processes. For example, the presence of tars in the gas poses a major challenge, and their decomposition in the reactor requires the use of special catalysts. Only a properly designed purification system, which includes dust filtration and the removal of sulphur and nitrogen, will ensure safe and stable operation.

Maximum efficiency: Use in combined heat and power generation

One of the most efficient ways of utilising wood gas is cogeneration – that is, the combined production of electricity and heat. In this process:

The gas powers a gas engine, which generates electricity.
At the same time, the thermal energy generated during the process is captured and utilised efficiently.

This approach maximises the energy yield from biomass and represents an environmentally and economically sustainable path towards a modern economy.