Research targeted on environmental issues

Pro­fes­sor Khasha­yar Saleh, direc­tor of UTC-TIMR, with activ­i­ties focussed on green chem­istry and asso­ciate process­es. Research areas such as decar­bonised ener­gy process­es, bio-sourced prod­ucts and the recov­ery of non-con­ven­tion­al waste are prioritised.

One of our flag­ship car­bon-free process projects? «One of our main areas of research con­cerns the stor­age of sol­id hydro­gen, an ener­gy car­ri­er with very high ener­gy capac­i­ties. Gen­er­al­ly speak­ing, we use gaseous car­ri­ers to achieve high yields and effi­cien­cy. And the gaseous state implies the need for stor­age under pres­sure. Hydro­gen is the small­est chem­i­cal ele­ment after heli­um, so you need a very high pres­sure of sev­er­al hun­dred bars to liq­ue­fy it, call­ing for a lot of ener­gy,» he explains.

This prob­lem prompt­ed an indus­tri­al part­ner to ask the UTC-TIMR-IMiD team to explore alter­na­tives to hydro­gen stor­age. «The idea is to store the hydro­gen in a pow­der based on met­al hydrides, which are absorbent car­ri­ers made up of matri­ces capa­ble of con­dens­ing the hydro­gen into chem­i­cal form,» he says. How can this be seen as of inter­est? «Well, we shall be able to store hydro­gen at much low­er pres­sures. If we look at the issue of mobil­i­ty, in oth­er words on-board use, we’ll be able to replace the petrol tank with car­tridges. This already exists, fit­ted to some scoot­ers. We’ll also be able to pow­er bat­ter­ies with fuel cells. It’s also safer stor­age, because the risks are not the same in the event of an acci­dent, with a 20-bar tank com­pared with near­ly 700–800 bar for a liq­uid stor­age tank. We have clear­ly demon­strat­ed the capac­i­ty to absorb hydro­gen on a sol­id sup­port and at pres­sures and tem­per­a­tures com­pat­i­ble with the use of a vehi­cle,» explains Khasha­yar Saleh.

The fea­si­bil­i­ty of this tech­nol­o­gy has there­fore been demon­strat­ed, although a num­ber of chal­lenges do remain. «The first con­cerns the den­si­ty or quan­ti­ty of hydro­gen that can be incor­po­rat­ed into the sol­id, giv­en that the cur­rent yield is 2%, i.e. for every 100 kg of sol­id, we only get 2 kg of hydro­gen. To have a range of 500 km, you need 5 kg of hydro­gen. So that’s the sec­ond chal­lenge, that of den­si­ty, because we need to incor­po­rate 250 kg of sol­id mat­ter into the matrix. At a time when con­struc­tors are light­en­ing the weight of vehi­cles to make them more fuel-effi­cient, this pos­es a prob­lem. These are two chal­lenges that can be solved in sta­tion­ary appli­ca­tions, but are more dif­fi­cult to meet in on-board appli­ca­tions. The third chal­lenge is load­ing and unload­ing on com­mand. If we take the exam­ple of a hydro­gen sta­tion, charg­ing needs to be fast. There are two pos­si­ble sce­nar­ios: either you charge direct­ly or you pur­chase pre-charged tanks, a solu­tion that has been adopt­ed for scoot­ers and elec­tric bicy­cles. It’s a tech­nol­o­gy that works for both small and heavy vehi­cles, but the equa­tion has yet to be solved for inter­me­di­ate vehi­cles such as cars, vans and so on. It’s a tech­nol­o­gy that has real envi­ron­men­tal advan­tages over fos­sil fuels, with zero CO2, CO or NOx emis­sions,» he points out. As well as ener­gy, the UTC-TIMR team is also inter­est­ed in find­ing alter­na­tive solu­tions to chem­i­cal plant pro­tec­tion prod­ucts. «In this area, we are faced with both envi­ron­men­tal and eco­nom­ic con­cerns. Again, there is the prob­lem of the yield of a crop pro­tec­tion appli­ca­tion. When spray­ing plants, over 50% of the prod­uct may be dis­persed into the envi­ron­ment for a vari­ety of rea­sons: either it miss­es its tar­get because of the wind, for exam­ple, or it encoun­ters rebound phe­nom­e­na and final­ly it is sub­ject to evap­o­ra­tion. This cre­ates not only a prob­lem of pol­lu­tion, but also of effi­cien­cy. One of the solu­tions lies in the for­mu­la­tion of anti-drift plant pro­tec­tion prod­ucts, a com­bi­na­tion of for­mu­la­tion and tech­nol­o­gy. This is the objec­tive we are pur­su­ing with the STIMULE FAUVE project, fund­ed by the Hauts­de- France Region and led by Audrey Drelich, a lec­tur­er-cum-research sci­en­tist work­ing in this UTC-TIMR unit. The aim is to antic­i­pate the advent of new prac­tices (e.g., treat­ment by drone) or the end of cer­tain phy­tosan­i­tary prod­ucts by devel­op­ing bio-sourced prod­ucts», he assures us.

Can you men­tion oth­er areas of research? «In the long term, we have defined three areas of research: the first con­cerns all decar­bonised ener­gy process­es; the sec­ond relates to biosourced prod­ucts; and final­ly, the third area is the reduc­tion of envi­ron­men­tal impact and the recov­ery of waste, whether the lat­ter be con­ven­tion­al or non-con­ven­tion­al», con­cludes Khasha­yar Saleh.

Le magazine

Avril 2024 - N°62

Faire face aux enjeux environnementaux

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