Methanization is a process that establishes the ideal conditions for the natural degradation of biowaste, to transform it into resources: biogas and digestate.

Construction has been accelerating in France since the early 2000s, and particularly over the last 5 years, when the injection recovery model (production of biomethane injected into natural gas networks) has dominated the market. This model is more expensive to set up, but it is also more profitable.

Existing systems continue to be explored and deepened over time, to move towards ever more efficient constructions while remaining responsible. In this article we give you some examples of emerging technologies or methods in the field of methanization.

Many innovations are emerging in reactor design: fixed bed reactors, fluidized bed reactors and membrane reactors, etc. By optimizing these parts, we can increase the efficiency of biogas production and therefore the yield of a methanization site.

For example, fixed-bed reactors use a solid support to which bacteria attach, thereby increasing the digestion surface area.

Fluidized bed reactors allow more efficient circulation of organic waste within the reactor to improve mixing and digestion.

Membrane bioreactors are equipped with special membranes that allow bacteria to remain in the reactor while allowing biogas to pass through – this increases the efficiency of the process and facilitates biogas recovery.

The pre-treatment of biowaste is also a sector in which innovations are developing. It is indeed very useful for certain wastes that take a long time to decompose, to optimize the overall efficiency of the structure.

Thermal hydrolysis, for example, uses heat and pressure to cause the breakdown of complex organic materials into simpler compounds.

More sophisticated grinding techniques are also emerging to prepare waste by grinding it, which increases its digestibility.

The choice and distribution of substrates are also becoming increasingly better controlled thanks to research. This is now focusing on the possible use of specific substrates that could increase biogas production due to their particular chemical composition (such as microalgae for example).

Another area of ​​research is in biogas purification systems: there are currently 2 main systems.

The first is purification using selective membranes that allow methane to pass through while removing carbon dioxide and other gaseous impurities on one side (gas separation membranes), and water on the other to avoid moisture in the biogas (water separation membranes).

The second allows water treatment through several processes:

• Condensation: elimination of water vapor contained in the gas by liquefying it
• Demineralization: removal of dissolved salts and minerals (components of water) using ion exchange resins
• Filtration: removal of solid particles from the water present in the biogas (sand filters, cartridge filters, etc.)

Alongside these two systems, some innovations are developing.

Electrolysis can be used to separate carbon dioxide (CO₂) from biogas using special electrodes. This method can be more energy efficient than some other purification techniques.

Advanced adsorption on specific materials, such as modified zeolites or polymeric materials, can be used to selectively remove impurities from biogas, providing high-quality purification.

Liquid and selective absorption of CO2 through special solvents can be used. These solvents can be regenerated for reuse, making the process more sustainable.

Cryogenics involves cooling biogas to very low temperatures to condense impurities, which can then be removed. This method can be particularly effective in removing moisture from biogas.

Graphene-based filters can be used to selectively remove impurities from biogas due to the unique properties of graphene, providing more efficient filtration.

Finally, more advanced membranes , such as liquid crystal polymer membranes, are being developed to improve the efficiency of gas separation, particularly the removal of CO₂.

Research is also underway to innovate in energy storage systems produced , to more easily manage the flows generated.

In the field of system monitoring and control , new smart objects are emerging to monitor key parameters and be able to bounce back quickly in the event of variations. For example, there are smart sensors, and artificial intelligence can also be used to predict and optimize conditions.

Several units in France (in Troyes or in Occitanie for example) have been built with the aim of testing all types of ideas and technologies which could, if they prove themselves, be democratized later on French methanizers and around the world.

For any further information, please do not hesitate to contact us:louis@methappro.fr