Audrey Villot är forskningsprofessor vid Institutionen för energisystem och miljö vid IMT Atlantique. Audrey Villot var i Sverige den 3 till 8 november 2019 för att träffa sina svenska kollegor på Borås universitet och Chalmers. Dessa möten ledde till fantastiska samarbetsprojekt. Kolla in intervjun med Audrey Villot här nedan (på engelska).

 

You are a researcher at the ITM Atlantic and your research focuses on the valorisation of biomass. How does your research provide an answer to the energy transition?

The challenge of our time is to respond to future energy needs without resorting to fossil fuels. To do this, substitutes must be found for current energy carriers, which must be less polluting, particularly for the atmosphere. Our desire is to enter into a circular economy by reusing what is currently considered waste. My research focuses on the valorisation of the biomass of dry waste such as wood or agricultural waste such as straw or cereal bales. The objective is to find ways of recovering energy, materials and/or chemicals from this agro-industrial waste. A concrete example is the recovery of biosourced insulation (straw, hemp, flax) at the end of its life, which will either be reused as insulation or collected, sorted and recovered for energy.

The advantage of biomass is that it is a ”decarbonised” energy, i.e. with a zero global carbon dioxide (CO2) emission cycle. The best known biomass is wood, but there are many uses that compete with its energy use, such as furniture and construction. This is why we are trying to move towards other sources of unused biomass that can be valorised, as mentioned above.

Can you tell us more about your research projects?

We are trying, from biomass, to generate ”energetic” gases through thermochemical processes that allow flameless combustion at high temperatures and in the presence of a small amount of oxygen. This is called pyro-gasification. Unlike complete combustion, where the biomass is totally destroyed to produce CO2 and water vapour, this combustion, which is incomplete, allows the production of a gas that will contain hydrogen and methane (syngas), a carbonaceous solid residue (biochar) and a condensable liquid phase (pyrolysis oil). The syngas, after appropriate treatment, can be reintroduced into the natural gas network and recovered for energy purposes. There are also energy or material recoveries for the other two phases.

Even if decarbonised energy does not emit CO2, this does not mean that it is not polluting. Indeed, burning wood leads to the formation of gases, Nox (nitrogen oxides) and Sox (sulphur oxides) to a lesser extent, as well as fine particles. My second part of research is therefore based on the treatment and purification of these gases. We are currently in a consortium with industrialists and laboratories to develop an individual filtration system to prevent the release of fine particles in domestic stoves.

You were a winner of the TOR mobility programme in 2019, which enabled you to travel to Sweden. Did your stay lead to a project?

We had initiated a first contact with a researcher from the University of Borås, with whom we had complementary areas of research, during a seminar. This TOR grant allowed me to go there, to exchange more and to lead to a collaboration. Our project focuses on the valorisation of a by-product of the gasification process, the char (or biochar). Currently, the management of this ”waste” leads to treatment costs that impact the economic profitability of the sector.

The University of Borås is working on the recovery of wet biomass, such as food waste, in bioreactors to produce methane. Biomass degradation processes are intensified through the use of fungi and bacteria, which are fed with substrates.

We are investigating the possibility of using tanks, which already contain the inorganic elements necessary for the development of bacteria, as a substrate for fungal growth.

We are also in contact with another Swedish university for a project on the use of activated carbon in tanks. 75-80% of the world’s production of activated carbon comes from mined coal. We would therefore like to study the possibility of transforming chars into activated coal, by playing on the porosity of the material, to limit the use of fossil resources and to recover chars that is currently considered as waste. Activated carbons are used in water or air treatment to capture pollutants.