Energy and environment : a plethora of projects …

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With a specialised department, the DSEE, and two semi-industrial platforms, Prever and SafeAir, equipped with a range of excellent facilities, the school is at the forefront of these two subjects.

The treatment of industrial or household waste and how to ensure the quality of the air we breathe, are issues related to energy and the environment, which concern more and more society in general, and which take pride of place at the Mines de Nantes. The school has a recognised centre of excellence for these subjects : the department of energy systems and environmental engineering.
With a total of 65 people working in the department, including 22 teacher-researchers, the DSEE is working on projects such as generating energy from waste, or the energy requirements of a particular area – a  district, or industrial zone- in order to optimize energy consumption. On the environmental side, it is working on indoor air treatment, and on industrial emissions, as well as on the treatment of certain industrial gas emissions. The department has called on a number of specialists from different disciplines.
As the head of the DSEE, Laurence Le Coq puts it "We want to bring together different expertise".
The DSEE has two key tools : two semi-industrial platforms, equipped with state of the art facilities.
 "They enable us to investigate not only how a material or a pollutant behaves under laboratory conditions, but also under real conditions, in real situations " explains Laurence Le Coq.
The first platform, called Prever, has just been set up on the school campus. Focusing on waste energy conversion, it represents a total investment of five million euros, financed by the state, the region, the FEDER (European fund for economic and regional development) and the city of Nantes. There are solid and liquid fuel boilers, engine test cells, a gas micro-turbine, equipment for the measurement and analysis of the characteristics of solids, liquids and gases."It is rare for a laboratory to have such high level equipment at its disposal. The facilities are quite unique", adds Mohand Tazerout, lecturer in charge of Prever. It is possible to study the whole chain, from the different types of waste to the kinds of fuel that can be obtained, and the different energy conversion systems, either heating or cooling."The objective is not large scale work, but rather to achieve good energy efficiency, with an acceptable level of emissions.", explains Laurence Le Coq.
The team in charge of Prever is involved with several projects with industrialists. The most ambitious, Iwest (Integrated Waste to Energy Shipboard Technology) is with the naval shipyard STX in St.Nazaire, Bureau Veritas and Leroux & Lotz Technologies, and concerns cruise ships. As Mohand Tazerout explains, "With thousands of passengers, every day several tonnes of domestic waste are produced, which cannot be incinerated. So we want to recyle the waste on board, through pyrolysis and gasification. In this way, it would be possible to produce electricity or thermal energy, with a lower level of emissions."  This project,  financed within the framework of an FUI programme, has enabled us to complete the research stage, by building a laboratory prototype, however certain finishing touches still need to be made, before a semi-industrial prototype can be built.
Within the framework of Prever, the team has also been working with Oxalor, a semi-public company in  Poitou-Charente, specialised in the sorting and recycling of domestic waste. The process consists in separating the different elements found in household waste : cardboard, plastics, and metal. Any organic matter is turned into fertilizer. What is left after that can be used for solid recovered fuel (SRF), and if the necessary processes are put in place, this in turn can be used to fuel an electricity plant. This is what the research team are working towards, with the help of public funding, to design a laboratory prototype for recling SRF.


SafeAir : three disciplines at the service of air quality


The second platform, SafeAir, with six laboratories, is working on air quality in homes, office buildings and factories. "We spend 80% of our time in enclosed spaces, where the air quality can be affected by a number of different elements, in particular, from building materials, and the materials used for decoration and furniture, as well as the activities of the occupants  : gaseous compounds, nanoparticles, and microbien aerosols ( bacteria, fungi, and viruses...)" points out Yves Andres, who runs an environmental engineering team,"These elements can cause discomfort, and can even cause illnesses or allergies". SafeAir draws from skills in three disciplines : microbiology, chemistry and process engineering.
A thesis has recently been submitted, in liason with Véolia, on the elimination of microbien aerosols.
SafeAir is working on the behaviour of aerosols on filters in air handling units (air conditioning, ventilation systems.....) depending on different parameters such as humidity, weather, and temperature... What happens to them once the air conditioning is switched off ? "We are also looking at different types of filters, at their shape for example", says Yves Andres. Here again, work has been done at laboratory level, as well as working on filters from actual sites. The objective is to draw up recommendations for use : for example, should airflow be continued during a holiday period ? There is a possibility of a partnership with the University of Hong Kong, to work on filters, within the framework of an international project.
The SafeAir team in involved in several major projects, such as NanoFlueGas (see below), PhotoCair and ETAPE which use photocatalytic air purification (using titanium dioxide) to purify indoor air."When titanium dioxide is exposed to light, it emits reactive species which attack the pollutants, break them down, and destroy them, explains Valérie Héquet, lecturer-researcher at the DSEE. Furthermore, titanium dioxide regenerates easily, and is inexpensive." The process can be used to remove certain pollutants such as volatile organic compounds (VOCs) which include benzene and formaldehyde, found in building materials and glue. At the moment SafeAir is working with the Ecole des Mines in Douai, on a pilot scheme, which aims to validate the safety of the process for indoor air, before commercializing it. This programme is financed by the Ademe (Energy and Environment Agency).
The fast expanding team at SafeAir plans to focus on other types of mico-organisms, viruses, possibly working with the School of Public Health in Rennes. Suffice to say that with these two platforms, the DSEE is not short of projects...


NanoFlueGas, or how to handle waste containing nanoparticles, in optimal conditions.

Assessing the risks involved in the incineration of nanomaterials and examining good practice in waste treatment, is one of the projects that the team at SafeAir has been working on since 2011. The project is called NanoFlueGas, and is coordinated by Ineris (French National Institute for Industrial Environment and Risks), led by the company Tredi (part of the Séché Environnement group) and co-financed by the Ademe.
Up till now, there has been no branch specialised in dealing with the management and treatment of nanomaterials at the end of their life cycle. The work now being carried out by NanoFlueGas forms some  of the first scientific steps towards dealing with the problem. They have been able to draw some reassuring conclusions : "The systems in use today perform relatively well, according to Laurence Le Coq. Certain nanoparticles disappear, while others appear at very low levels. But to confirm these findings, further work needs to be done, to explore other families of particles , perhaps other conditions of treatment, (particularly degraded), in order to provide robust recommendations to improve good practice in the industry"  The challenge is all the more important as it concerns an area where the regulations are changing, and becoming more and more restrictive. "Throughout the programme we have provided our skills and expertise concerning incineration, and were the first to contribute to identifying sources of  structured particles, explains  Sylvain Durécu, Head of Research at Trédi.  It is a highly fruitful collaborative effort, which has led to a positive result."

The starting point for this project, was work on a thesis put forward by the DSEE, concerning particles likely to cause public health problems : how do particles in suspension behave in an airflow, a pipe or air-conditioning duct for example? What conditions cause them to be deposited on the walls, or are they actually put into circulation again ? These subjects are of great interest to other industrial partners, for example in the nuclear science sector, in the food industry, and in micro-electronics.
The NanoFlueGas project comes to an end next August. But it could well be extended over the next three years."That would enable us to examin other treatment systems alredy in use, such as electro filters, explains Sylvain Durécu. There are interesting prospects ahead." It is a vast subject, with a certain number of questions which remain unanswered. A decision will be made over the coming weeks.


Closer links with industry

Finding funding in order to carry out research is a constant concern for a department like the DSEE. Even more so in times like these, with budget restriction both from the state and from industry... "Of course, we try to get public funding whenever there is a good chance of a rapid return on investment, says Laurence Le Coq. But in general, people are less willing to take financial risks than before. We are managing to carry out projects which were already up and running, making headway on the work in hand. However it is much more difficult to finance new ideas, especially if they require a sizeable investment at the outset."
To get round this problem, the DSEE is working more and more with industry. This may be in a direct way, with contracts for research, or in the form of bids for different projects. The department spends much time in discussion with company directors, before bidding for projects.
This is why it is so important to have long term partners. Industrial research chairs, which generate funding over several years, are a good example of this. In this way, the DSEE set up a research chair with Séché Environnement."We established three subject on which we could work together, over aperiod of four years", explains Laurence Le Coq. Véolia is another long term partner, involved in the European Doctoral School, to which the school belongs.
These 'historic' industrial partners are also involved with the Laboratory Science Council and the Research Committee of the school. "However, as Laurence Le Coq points out, working with PMEs is more difficult because, they sometimes do not associate us with the right subjects.."

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