Valorization Routes Research Articles

Bioethanol fermentation as alternative valorization route of agricultural digestate according to a biorefinery approach

This study investigates the feasibility of producing bioethanol from solid digestate after a mechanical fractionation (i.e. centrifugal milling), in order to improve the energy recovery from agricultural wastes and the sustainability of anaerobic digestion plants. A bioethanol yield of 37gkg−1TS was evaluated for the solid digestate fraction. Mass and energetic balances were performed and compared between two scenarios: (A) one-stage bioethanol fermentation and (B) two-stage anaerobic digestion–bioethanol fermentation, in order to evaluate the feasibility and the advantages of the two-stage process. Results revealed that, compared to the one-stage process, the dual anaerobic digestion–bioethanol process permitted: (i) to diversify biofuels production; (ii) to provide the thermal energy sufficient for drying digestate (13,351kWhthday−1), for the subsequent milling step; (iii) to reduce the electric energy requirement for the milling step (from 23,880 to 3580kWhelday−1); (iv) to produce extra electrical energy of 8483kWhelday−1; (v) to improve the reduction of waste streams generated (from 13% to 54% of organic matter removal).

Life cycle assessment of hybrid vehicles recycling: Comparison of three business lines of dismantling

This paper undertakes an environmental evaluation of hybrid vehicles recycling, using industrial data from Comet Traitement SA in Belgium. Three business lines have been modelled and analysed. The first one is relative to the business as usual with a dismantling to recover batteries and engines followed by shredding and post shredding treatments. The second one considers, in addition, the removal of electronic control units (ECU) before shredding followed by same steps than in the first line and the last one is relative to the additional removal of big plastic parts before shredding and business as usual post shredding treatments. Results show non-significant environmental benefits when ECU or large parts of plastics are recovered before shredding. Improvements in terms of environmental benefits are lower than the uncertainty of the results. Indeed, the performing usual process for end-of-life vehicles (ELV) treatment reaches 97% of the ELV which is valorised in terms of metal and energy recoveries. Post shredding treatment units include metals, plastics and energy recovery of residues. Comet business as usual route for ELV valorisation is in accordance with the requirements of the European directive and recommendations for further improvement with dismantling of other parts (ECU or plastics) before shredding are non-relevant in this case.

Exploring Orange Peel Treatment with Deep Eutectic Solvents and Diluted Organic Acids

The disintegration of orange peel waste in deep eutectic solvents and diluted organic acids is presented in this work. The albedo and flavedo layers of the peel were studied separately, showing faster disintegration of the latter. Addition of water to the deep eutectic solvents lowered the amount of remaining solids and improved the disintegration times. These improvements are subscribed to a decrease in viscosity upon deep eutectic solvent dilution. Each of the individual deep eutectic solvent components were diluted and subjected to the same disintegration tests. The corresponding diluted organic acids showed similar orange peel disintegration performance as the tested deep eutectic solvents, whereas dilutions of the other counterparts did not show any activity. Hence, the active deep eutectic solvent components during orange peel treatment are considered to be their organic acids. Flavonoids and essential oils were released during the treatment, offering new opportunities for the development of orange peel waste valorisation routes.

Kraft delignification of energy crops in view of pulp production and lignin valorization

The hardwoods Acacia dealbata (mimosa), Salix spp. (willow), and the perennial plants Arundo donax (giant reed) and Miscanthus giganteus (giant Chinese silver grass) are important energy crops, with low requirements and high productivity. The polysaccharide content of these species has drawn attention as source of sugars for biobased products. In this work, biomasses were deconstructed by kraft pulping, evaluating final pulp yields as well as residual lignin (kappa number, KN) as indicators of the pulp quality for conversion to sugars. The black liquors and lignin in the isolated materials were evaluated concerning composition and structural characterization parameters with relevance to further valorizations routes, such as production of vanillin and syringaldehyde. The best trade-off between pulp yield and KN were achieved for 160°C and pulping time 210min, with active alkali (AA) 22% for mimosa and willow and AA 18% for giant reed; these three biomasses presented similar pulp yields (45–47%) and KN (13–15). For silver grass a lower AA (16%) and the combination of higher temperature/lower pulping time (170°C/180min) were selected. Among the four, silver grass presented the highest pulp yield (51.5%) and the lowest KN (10), which is the first advantage identified for this species. Another advantage is the higher production of lignin by isolation from black liquor (128g/kg of biomass), compared to the other materials (88–119g/kg), with the additional benefit of low contamination with inorganic compounds. The isolation of lignins is favorable for the valorization route involving oxidative depolymerization. The structural analysis of lignins and the comparison between the frequency of the main interlinkages and functional groups allowed drawing remarks about their suitability for some applications. The data presented are a tool for decision about the best exploitation route for lignin, contributing for the valorization of the streams generated in biorefining processes of energy crops.

Cork extractives exhibit thermo-oxidative protection properties in polypropylene–cork composites and as direct additives for polypropylene

The thermo-oxidative stability of polypropylene (PP) in composites containing 15 wt.% of cork and the performance of selected cork extracts as stabilizing additives for PP was evaluated by Oxidation Induction Time (OIT) and by Oxidation Onset Temperature (OOT). The results showed that cork increases the OIT of PP in the composite and it was identified that the cork extractives fraction is responsible for such behavior. Selected cork extracts with high antioxidant capacity (determined by dpph radical scavenging and oxygen reactive absorbance capacity assays) were compounded by extrusion with PP in 0.5 and 1.5 wt.%. It was found that the ethanol extract is the most effective as thermo-oxidative stabilizer for PP. At the loading level of 1.5%, the OIT increases from 3.8 (neat PP) to 29.7 min at 200 °C and from 1.2 (neat PP) to 9.0 min at 220 °C. The OOT also increases from 216 °C (neat PP) to 247 °C. Mechanical tests, performed on PP loaded with the cork extracts, showed that the presence of these extracts has no significant effect on the polymer mechanical performance. The results demonstrate the suitability of cork as a source of thermo-oxidative stabilizing additives for the formulation of polyolefins, and enable the exploitation of new routes of cork valorization.

Valorization of thermal treatment residues in Enhanced Landfill Mining: environmental and economic evaluation

Enhanced Landfill Mining is an innovative concept which allows the recovery of land, re-introduction of materials to the material cycles and recovery of energy from a considerably large stock of resources held in landfills. Plasma gasification is a viable candidate for combined energy and material valorization in the framework of Enhanced landfill Mining. Besides energy production, plasma gasification also delivers an environmentally stable vitrified residue called plasmastone, which can be converted into building materials. This paper presents an environmental and economic evaluation of the valorization of thermal treatment residues (plasmastone) in the context of Enhanced Landfill Mining. The most common valorization route, that is, the treatment of plasmastone via production of aggregates, is compared with two other possible, higher added value applications, which are inorganic polymer production and blended cement production. The evaluation is based on life cycle assessment and life cycle costing. The study suggests that the environmental and economic performances of the valorization routes depend mainly on the quality and quantity of the final products produced from a certain amount of plasmastone. The materials with the greatest contribution to potential global warming and to the net present value of the valorization scenarios are the process input materials of sodium silicate, sodium hydroxide and cement. The study concludes that the plasmastone valorization via inorganic polymer production yields higher environmental benefits, while the blended cement production provides higher economic profits. Plasmastone valorization via aggregates production does not yield economic or environmental benefits. Given the trade-off between environmental and economic performances, we conclude that the decisions regarding the selection of appropriate valorization routes should be made cautiously to obtain optimal environmental benefits and economic profits.

Phosphoric acid intercalated Mg–Al hydrotalcite-like compounds for catalytic carboxylation reaction of methanol in a continuous system

Mg–Al-hydrotalcite-like catalysts (HTlcs) with different amount of P/Mg molar ratio were prepared via co-precipitation method and calcined at 450°C. The synthesized catalysts were tested in the direct-carboxylation reaction of methanol in gas phase in a continuous system such as chemical route for CO2 valorization. Activities around 2% with total selectivity towards the dimethyl carbonate (DMC) was obtained at moderate temperatures (150°C) with both Mg/Al mixed oxides (HTO) and phosphated Mg/Al mixed oxides (HTc-9c). Even though the conversion increased until 16% at higher temperatures (200°C), the selectivity with both catalysts (HTO and HTc-9c) decreased due to the decomposition of DMC to dimethyl ether (DME). Nevertheless, the catalyst with P showed less DMC decomposition and a higher selectivity towards the desired product. This is explained by the presence of orthophosphate species bonded to the Al3+ metals of the HTs (OP(OAl)3) which give to the catalyst a higher structural stability and specific acid properties.In addition, the solids were characterized in-depth by XRD, ICP, NH3-TPD, FTIR, Raman, 27Al and 31P MAS NMR spectroscopy and SEM.

Use of Fleshings-Derived Collagen in Chrome Tanning Process

The manufacturing process to transform hides into leather requires a series of chemical and mechanical operations. Fleshings represent one of the most important byproduct of the leather compartment. They are mainly constituted of raw collagen and through an alkaline hydrolysis a collagenous solution is obtained. In this work, an experimental activity research was performed for assessing the feasibility of the reuse of the collagen hydrolizate solution in the tanning phase. The hydrolizate has been used in combination with chromium salts to obtain bovine upper leather up to a dosage of 20% of solution (68% dry protein matter content) on the fleshed hide weight. Following a laboratory scale screening of the optimal operating conditions, crust leathers have been obtained on pilot scale. The final leather shows similar properties to those of the traditionally tanned leather in terms of technical and mechanical properties. Furthermore, a dry tannage is feasible, thus avoiding the production of effluents, and it is possible to adopt a retannage/dyeing/fatliquoring characterized by a lower consumption of chemicals in comparison with the standard procedure. The results obtained indicate the use of the collagen hydrolizate in the tanning phase as an interesting route for valorisation of fleshings.

Evaluation of chemical processing impact on E. globulus wood lignin and comparison with bark lignin

In this work a comprehensive characterization of different Eucalyptus globulus lignins was performed in order to evaluate the influence of the industrial process on its structure: LOrg – lignin produced by organosolv process, LKraft – lignin isolated from black liquor (obtained by kraft process) and further purified, taking LEgwood – lignin produced by wood mild acidolysis, as representative of wood lignin. Lignin from bark, LEgbark, also isolated by mild acidolysis, was characterized and compared with LEgwood. Besides the contaminants content (inorganic material plus carbohydrates – 1–3%), lignins structure were studied with reference to yields obtained by nitrobenzene oxidation (NO), and with reference to functional groups and typical structures/linkages by quantitative 13C, 1H and 31P nuclear magnetic resonance (NMR). NO yield order was found to be LKraft (21%)<LOrg (26%)<LEgwood (31%)≈LEgbark (33%), demonstrating that the industrial processing, particularly the kraft one, induced unfavorable changes for a valorization route involving production of functionalized aldehydes by depolymerization. The main changes were the increase of degree of condensation (DC), cleavage of β-aryl ether linkages, and demethoxylation, in particular for the lignin resulting from the kraft process. The NO yield was successful correlated with DC and Syringyl/Guaiacyl (S/G) ratio from 31P NMR and also a good correlation was obtained between β-aryl ether content and DC, clearly ascertaining the structural features related with the potential of the E. globulus lignin as source of functionalized aldehydes. LEgwood and LEgbark have similar structures, whilst the presence of p-hydroxyphenyl (H) detected in the bark lignin leads to a S:G:H (73:23:4) different from wood lignin (80:20:0). The overall results showed that organosolv or a mild delignification process would be a preferable process to obtain lignin from E. globulus wood or bark for production of functionalized aldehydes.

Compositional insights and valorization pathways for carbonaceous material deposited during bio-oil thermal treatment.

This work analyses the composition, morphology, and thermal behavior of the carbonaceous materials deposited during the thermal treatment of bio-oil (thermal pyrolytic lignin-TPL). The bio-oil was obtained by flash pyrolysis of lignocellulosic biomass (pine sawdust), and the TPLs were obtained in the 400-700 °C range. The TPLs were characterized by performing elemental analysis; (13)C NMR, Raman, FTIR, and X-ray photoelectron spectroscopy; SEM; and temperature-programmed oxidation analyzed by differential thermogravimetry and differential scanning calorimetry. The results are compared to a commercial lignin (CL). The TPLs have lower oxygen and hydrogen contents and a greater aromaticity and structural order than the CL material. Based on these features, different valorization routes are proposed: the TPL obtained at 500 °C is suitable for use as a fuel, and the TPL obtained at 700 °C has a suitable morphology and composition for use as an adsorbent or catalyst support.

A mechanism of gas-phase alcohol oxidation at the interface of Au nanoparticles and a MgCuCr2O4spinel support

The catalytic oxidation of bio-ethanol to acetaldehyde entails a promising route for valorization of biomass into many important chemicals that are currently mainly being produced from fossil-based ethylene feedstock. We employ here DFT calculations to understand the unprecedented synergy between gold clusters and a MgCuCr2O4 spinel support, which shows excellent catalytic performance for the oxidation of ethanol to acetaldehyde (space-time yield of 311 gacetaldehyde ggold−1 h−1 at 250 °C). The investigations support a mechanism involving catalytic reactions at the gold–support interface. Dissociative adsorption of ethanol is facilitated by cooperative action of a gold atom at the metal cluster–support interface and a basic oxygen atom of the support. The most difficult step is the recombinative desorption of water from the surface. The oxygen vacancy formation energy is found to be a good performance descriptor for ethanol oxidation of Au/MgMeCr2O4 (Me = Cu, Ni, Co) catalysts. The high selectivity towards acetaldehyde stems from the facile desorption of acetaldehyde as compared to the cleavage of the remaining α-C–H bond in the product. The opposite holds for methanol oxidation, explaining why experimentally we observe complete methanol oxidation over Au/MgCuCr2O4 under conditions where ethanol is selectively converted to acetaldehyde.

Glycerol conversion in the presence of carbon dioxide on alumina supported nickel catalyst

The glycerol conversion in the presence of carbon dioxide was investigated on a Ni/γ-Al2O3 catalyst. The catalyst was characterized by XRD, TPR, BET, XPS, H2-TPD, DRIFTS and Raman. A catalyst preparation method using ethylene glycol and a reduction passivation procedure provided an active catalyst. For the different catalytic runs in a batch reactor, a higher formation of hydrocarbons, alcohols, ketones, and furans was observed when the mass of catalyst was increased. For temperatures below 200°C, both glycerol and CO2 were converted, suggesting a potential route for glycerol valorization and CO2 sequestration, with the consequent production of oxirane, alcohols, ketones and carboxylic acids. For higher temperatures, there was the formation of a wide range of low yield products, with higher yields to ketones, alcohols and esters.

Lignin extraction from Mediterranean agro-wastes: Impact of pretreatment conditions on lignin chemical structure and thermal degradation behavior

Three different types of Mediterranean, agro-industrial wastes (olive kernels, grape pomace/seeds, peach kernels), were subjected to two pretreatment processes, a chemical/organosolv and a physicochemical one. The organosolv process included lignocellulosic biomass treatment with formic acid/acetic acid/water (30/50/20, v/v%), for 3h at 107°C, while the physicochemical method was conducted by immersing the biomass in a water/ethanol (8/92, v/v%), H2SO4 0.32M, solvent and further exposing the slurry to microwave irradiation (maximum 250W) for 1/2h at 150°C. Both processes were evaluated regarding the achieved delignification and the purity of the extracted lignins. The effect of the pretreatment processes onto the structure and thermal decomposition behavior of the extracted lignins was investigated via FT-IR and TGA analysis, respectively. The objective of the research work was to investigate potential valorization routes for these biomass agro-residues in the context of a biorefinery, focusing on lignin extraction. The pretreatment results showed that the obtained lignins, derived from both procedures, were of high purity (>82wt%). Under the organosolv procedure, peach kernel delignification showed the maximum value (∼16wt%), while under microwave pretreatment, olive kernel delignification showed the maximum value (∼35wt%). Grape pomace/seeds appeared to be the most resistant in both treatments.

Potential application of pyrolysis for the effective valorisation of the end of life tires in Greece

Used tires (UTs) are an abandon solid waste in Greece and worldwide which can be effectively transformed to valuable products and energy via pyrolysis. In this study, current status of both European and Greek Legislation on waste management with a special insight in tires is reported. The established Joint Alternative Management System (JAMS) for the alternative management of tires is described, along with the adopted valorization routes. The adopted Energy recovery routes in Greece are discussed with focus on pyrolysis. The main drawbacks of pyrolysis are identified and solutions are proposed for their effective implementation in the near future. Tires energy and material recovery are particularly favorable, with substantial benefits of energy savings, material recovery and high added materials production. Based on the existing extensive expertise in the pyrolysis of tires, an effort was made in order to identify the non-technical barriers for the further exploitation of pyrolysis as a promising valorization route in Greece. A SWOT analysis was further developed for the comparison of pyrolysis with combustion and the results are also presented.

Stabilization of basic oxygen furnace slag by hot-stage carbonation treatment

Treatment and disposal of Basic Oxygen Furnace (BOF) slag, a residue of the steel production process characterized by high basicity and propensity for heavy metal leaching, is a costly burden on metallurgical plants; a sustainable valorization route is desired. The stabilization of BOF slag utilizing hot-stage carbonation treatment was investigated; this approach envisions carbonation during the hot-to-cold pathway followed by the material after the molten slag is poured and solidified. Three experimental methodologies were employed: (i) in situ thermogravimetric analyzer (TGA) carbonation was used to assess carbonation reaction kinetics and thermodynamic equilibrium at high temperatures; (ii) pressurized basket reactor carbonation was used to assess the effects of pressurization, steam addition and slag particle size; and (iii) atmospheric furnace carbonation was used to assess the effect of carbonation on the mineralogy, basicity and heavy metal leaching properties of the slag. Free lime was found to be the primary mineral participating in direct carbonation of BOF slag. Initial carbonation kinetics were comparable at temperatures ranging from 500 to 800°C, but higher temperatures aided in solid state diffusion of CO2 into the unreacted particle core, thus increasing overall CO2 uptake. The optimum carbonation temperature of both BOF slag and pure lime lies just below the transition temperature between carbonation stability and carbonate decomposition: 830–850°C and 750–770°C at 1atm and 0.2atm CO2 partial pressures, respectively. Pressurization and steam addition contribute marginally to CO2 uptake. CO2 uptake progressively decreases with increasing particle size, but basicity reduction is similar independent of particle size. The solubility of some heavy metals reduced after carbonation (barium, cobalt and nickel), but vanadium and chromium leaching increased.

Characterization of landfilled materials: screening of the enhanced landfill mining potential

The main objective of “Enhanced landfill mining” is the valorization of the excavated waste materials that have been stored in the landfill. Previous landfill mining projects have shown that each landfill site has its own potential with regard to landfill mining. Factors such as the age of the landfill, type of landfill and the country or region where the landfill is located might have an impact on the type of materials stored in the landfill and their valorization potential. In the present article, the valorization options for the materials stored at the REMO site in Houthalen (Belgium) are assessed based on excavation tests done at locations containing either municipal solid waste (MSW) or industrial waste (IW). The results reveal differences in the composition and the characteristics of the waste materials with regard to type of waste (MSW versus IW) and the period during which the waste was stored. Based on the characteristics of the different fractions, an initial assessment was made with regard to their valorization potential. For the plastics, paper/cardboard, wood and textile recovered in this study, waste-to-energy is the most suitable valorization route since the level of contamination was too high to allow high quality material recycling. For metals, glass/ceramics, stones and other inerts in the waste, material valorization might be possible when the materials can adequately be separated. The amount of combustible in the excavated waste varied between 23 and 50% (w/w) with a calorific value of around 18 MJ kg−1 dw and confirm the large potential of waste-to-energy for landfill mining. All waste samples recovered from the landfill contained a large amount (40–60% (w/w)) of a fine grained (<10 mm) mainly mineral waste material. Especially for industrial waste (mainly shredder from ELV), the fines contained high concentrations of heavy metals (Cu, Cr, Ni and Zn) and offer opportunities for metal extraction and recovery. The development of a treatment plant that enables maximum resource recovery remains however one of the technological challenges for further development of enhanced landfill mining.

New Routes of Valorization of Recycled and Bio-sourced Polyamides with a Low Toxicity Process

The aim of the present work is the development of new materials from renewable resources mixed with recycled polymers. The article focuses on the studies of (PAX/PA6) and (PAX/PA66) blends using three coupling agents: PBO, DGEBA, Lotader 3210. Blends of various compositions were prepared in a corotating twin-screw extruder. PA6 (PA66) acts as the polymer matrix and PAX as the dispersed phase. The morphology of the compatibilized PAX/PA6/DGEBA (25/75) and PAX/PA66/DGEBA (25/75) blends shows lower diameters and a decrease in the size of the dispersed PAX particles. The addition of DGEBA not only leads to a much finer phase domain size, but also improves the interphase between PA6 (PA66) and PAX phases. Moreover, rheological analysis indicates that the increase in viscosity was much more pronounced with DGEBA than with Lotader 3210 and PBO especially for PAX/PA6 (25/75) and PAX/PA66 (25/75) blends, which can be indicative of good reactivity of the terminal −NH2 groups of PA6 or PA66 with the epoxy groups of DGEBA. The improvement of interphase between phases induced an increase in tensile properties. VOC from PA66 were recovered and found not to modify the viability of human macrophages, which can be a sign of a low toxicity of the process.

Chemical and ecotoxicological properties of ashes produced in the co-combustion of coal and meat and bone meal in a fluidized bed reactor

The co-combustion of coal and meat and bone meal (MBM) is a possible energetic valorization route for this residue. Nevertheless, the properties of ashes produced need to be studied. To evaluate these properties, three combustion tests were performed in a fluidized bed reactor: 1) coal combustion; 2) coal+MBM (85%+15%) co-combustion; 3) MBM combustion. The characterization of ashes was focused on the following aspects: (1) Determination of bulk content of Cr, Zn, Ni, Cu, Pb, Cd, Hg, As, Ba, Mo, Sb, Se, Ca, Na, Mg, Fe, Al and K; (2) Leaching properties of ashes based on the European Standard EN12457-2. The eluates were characterized for some of the metals referred above and for Cr VI, CN−, pH, Cl−, F−, SO42−, dissolved organic carbon and total dissolved solids. The eluates were also characterized for ecotoxicological levels by using the following bio-indicators: bacterium V. fischeri, microalgae S. capricornutum and microcrustacean D. magna. The ashes produced in the combustion of coal and co-combustion of coal+MBM have not shown evidences of ecotoxicity, while the ashes produced in the combustion of MBM were classified as ecotoxic. An assessment of the relationship between the chemical and the ecotoxicological properties of the ashes was performed. pH seemed to be the chemical parameter that most influences the ecotoxicological level of ashes.

Gasification as an optimum alternative for the sludge management

Assimilate sludge to a fuel is not new. Sludge incineration and Combined Heat and Power (CHP) engines powered with sludge-derived anaerobic digestion gas (ADG) are operations widely used. However, they have a room of improvement to reach simultaneously a positive net power generation and a significant level of waste reduction and stabilization. Gasification has been used in other realms for the conversion of any negative-value carbon-based materials, that would otherwise be disposed as waste, to a gaseous product with a usable heating value for power generation . In fact, the produced gas, the so-called synthetic gas (or syngas), could be suitable for combined heat and power motors. Within this framework gasification could be seen as an optimum alternative for the sludge management that would allow the highest waste reduction yield (similar to incineration) with a high power generation. Although gasification remains a promising route for sewage sludge valorisation, campaigns of measurements show that is not a simple operation and there are still several technical issues to resolve before that gasification was considered to be fully applied in the sludge management. Fluidised bed was chosen by certain technology developers because it is an easy and well known process for solid combustion, and very suitable for non-conventional fuels. However, our tests showed a poor reliable process for gasification of sludge giving a low quality gas production with a significant amount of tars to be treated. The cleaning system that was proposed shows a very limited removal performance and difficulties to be operated. Within the sizes of more common WWTP, an alternative solution to the fluidised bed reactor would be the downdraft bed gasifier that was also audited. Most relevant data of this audit suggest that the technology is more adapted to the idea of sludge gasification presented in the beginning of this paper where a maximum waste reduction is achieved with a great electricity generation thanks to the use of a “good” quality syngas in a CHP engine. Audit show also that there is still some work to do in order to push sludge gasification to a more industrial stage. Regardless what solution would be preferred, the resulting gasification system would involve a more complex scenario compared to Anaerobic Digestion and Incineration, characterised by a thermal dryer and gasifier with a complete gas cleaning system. At the end, economics, reliability and mass and energy yields should be carefully analysed in order to set the place that gasification would play in the forthcoming processing of sewage sludge.

Carbon dioxide: a raw material and a future chemical fuel for a sustainable energy industry

Carbon dioxide is a major raw material of the future, for the capture plants which use amines, aminoacids, ammonia or zeolites. This very high purity raw material (99.9 %) opens the way of a new industrial revolution in agreement with the proposal of Nobel Prize laureates and the DOE strategy. Our goal is to explain the large advantages and the main routes for CO2 valorization, which are starting around the world. The most promising ways for this valorization are methanol synthesis as fuel for transportation and methane formation for electricity network regulation. The first way allows the use of liquid fuels, as distribution infrastructure already exists; instead of gaseous fuels (H2), for which there is storage, distribution problems and no infrastructure exist. The second way is methane synthesis during off-peak hours and burning of this methane during peak hours in order to regulate the electric network.