Gasoline, diesel, LPG, naphtha, kerosene. These fuels are the basis of the modern transport. But these fossil-derived fuels are produced from oil refining and their combustion involves the net emission of CO2 and several pollutants. Therefore, their use is not compatible anymore with the goals of the European Union, which aims – through the so-called “Green New Deal” programme – to become within 2050 the first carbon neutral continent in the world. If batteries and electric engines represent the most promising solution for cars (even if they just move the problem of carbon emission towards power generation), this solution is not feasible for heavy-duty trucks and for aviation and shipping sectors.
In these cases, the only promising solution is represented by the so-called “e-fuels”, derived from the overproduction of electrical energy from renewable sources and from CO2 captured from power generation plants, industries and possibly directly from the atmosphere. In this way, carbon dioxide, universally considered as a problem, becomes a resource.
Several studies are currently in progress worldwide. The results are very promising. And the first demonstration-scale applications are already available (e.g. the Carbon recycling International’s methanol plant in Iceland and the Audi’s methane unit in Germany). But the pathway to make e-fuels competitive with their fossil-derived counterparts is still very long.
In this context, Sotacarbo is actively engaged, since 2014, in the development of processes and catalysts for CO2 hydrogenation to e-fuels like methanol and dimethyl ether (DME). The former is considered as the ideal energy carrier and it is characterized by an increasingly international market, is also a precursor for countless chemical products. In parallel, DME – in addition to its current applications as solvent or propellent – can be considered as an excellent fuel for domestic applications (e.g. as a substitute of LPG) and to feed diesel engines.
In particular, Sotacarbo research is focused on the development of catalysts that – using innovative preparation methods and advanced materials – can allow very high performance.
The most surprising result is represented by a specific material, obtained combining the so-called sol-gel method with self-combustion technique to deposit the active phase (based on copper and zinc oxide) on a support composed by a mesoporous silica, with a pore size in the order of few nanometers (millionth of millimetres); this promotes the reaction between carbon dioxide and hydrogen.
Thanks to this approach, the product is characterized by excellent performance – significantly higher if compared with the competitors (in terms of production yield and selectivity) – and it is tolerant to oxygen (which makes the catalyst particularly interesting for some specific industrial applications). But, above all and differently from all the other catalysts developed for such a process, it doesn’t need any expensive pre-treatment. In other words, whereas conventional catalysts, once loaded into the reactor, must be pre-treated and reduced with high-temperature hydrogen (which means high costs, long shut-down phases and a number of safety problems), the new Sotacarbo methanol catalyst is basically “ready to use”.
The experimental results on this methanol catalyst are now widely recognized by the scientific community. The material is protected by an international patent application (PCT/EP2019/053068) published last October by the World Intellectual Property Organization (WIPO) and the experimental results have been recently published by the very eminent international journal “Applied Catalysis B: Environmental” (edited by Elsevier). And they won three major international prizes, the last one acknowledged during the 2019 edition of ICCDU, which is the most important conference worldwide on carbon dioxide utilization.
The results are very promising. The research is going on, thanks to the Regional Government of Sardinia (which funds the “Centre of Excellence on Clean Energy” project) and to the fruitful collaboration with few scientific partners: new catalysts are under preparation and characterization in collaboration with the University of Cagliari; a detailed kinetic study is in progress with the researchers of the Indian Institute of Technology Madras (one of the major universities in Asia); and new investigations have been planned with LEAP (Laboratorio Energia e Ambiente Piacenza) and Politecnico di Milano.
And – thanks to the Research on Electric System programme funded by the Italian Ministry of Economic Development – a new pilot-scale plant is under design and it will be completed within late 2021 to test and develop the integrated process in different operating conditions.
The pathway – as mentioned – is still long, but the finish line (i.e. the competitiveness of this technology with respect to the conventional ones) begins to emerge in sight. APettinau