BUSCADOR RECOLECTA

This review article presents the state-of-the-art on the catalytic oxidative steam reforming (OSR) of glycerol to produce syngas. Concerning the different technologies proposed for the catalytic OSR of glycerol, the following key points can be highlighted: (1) the robustness is much higher than other reforming technologies, (2) several catalysts can work with low deactivation, some of which can recover almost full activity by suitable regeneration, (3) syngas production by catalytic OSR of glycerin is higher than with concurrent technologies, (4) their scaling-up remains an unrealized task, (5) the thermodynamics of the process has been sufficiently covered in the literature, (6) there is a significant lack of kinetic and mechanistic studies that could help gaining deeper insight on the process, (7) novel concepts and reactor designs must be proposed for their development at larger scales, (8) new catalyst formulations must be developed for attaining higher resistance against oxidation and (9) process intensification could help developing them at larger scales., António Portugal and Rui Moreira are grateful to the Portuguese Foundation for Science and Technology (FCT) and the European Development Regional Fund (ERDF) for funding under the scope of the MultiBiorefinery project (POCI-01-0145-FEDER-016403). Luis M. Gandía thanks Banco de Santander and Universidad Pública de Navarra for their financial support under the 'Programa de Intensificación de la Investigación 2018' initiative. Fernando Bimbela and Luis M. Gandía wish to thank financial support from Spanish Ministerio de Ciencia, Innovación y Universidades , and the European Regional Development Fund ( ERDF / FEDER ) (grant RTI2018-096294-B-C31). José Luis Sánchez expresses his gratitude to Aragón Government (Ref. T22_20R), co-funded by FEDER 2014–2020 'Construyendo Europa desde Aragón' for providing frame support for this work.

In this work, the production of renewable hydrocarbons was explored by the means of waste cottonseed oil (WCSO) micropyrolysis at 500◦C. Catalytic upgrading of the pyrolysis vapors was studied using α-Al2O3, γ-Al2O3, Mo-Co/γ-Al2O3, and Mo-Ni/γ-Al2O3 catalysts. The oxygen removal efficiency was much lower in non-catalytic pyrolysis (18.0%), whilst γ-Al2O3 yielded a very high oxygen removal efficiency (91.8%), similar to that obtained with Mo-Co/γ-Al2O3 (92.8%) and higher than that attained with Mo-Ni/γ-Al2O3 (82.0%). Higher conversion yields into total renewable hydrocarbons were obtained with Mo-Co/γ-Al2O3 (61.9 wt.%) in comparison to Mo-Ni/γ-Al2O3 (46.6%). GC/MS analyses showed a relative chemical composition of 31.3, 86.4, and 92.6% of total renewable hydrocarbons and 58.7, 7.2, and 4.2% of oxygenated compounds for non-catalytic bio-oil (BOWCSO), BOMoNi and BOMoCo, respectively. The renewable hydrocarbons that were derived from BOMoNi and BOMoCo were mainly composed by olefins (35.3 and 33.4%), aromatics (31.4 and 28.9%), and paraffins (13.8 and 25.7%). The results revealed the catalysts’ effectiveness in FFA decarbonylation and decarboxylation, as evidenced by significant changes in the van Krevelen space, with the lowest O/C ratio values for BOMoCo and BOMoNi (O/C = 0–0.10) in relation to the BOWCSO (O/C = 0.10–0.20), and by a decrease in the presence of oxygenated compounds in the catalytic bio-oils., The authors from PEB research group (UFS) are grateful to CAPES (Coordination of Improvement of Higher Educational Personal) and CNPq (Brazilian National Research Council) for fellowships and CLQM (Center of Multi-users Chemistry Laboratories, Federal University of Sergipe) for analytical assistance. Authors from UPNA would like to acknowledge the use of Servicio General de Apoyo a la Investigación-SAI, Universidad de Zaragoza, in particular Ana Guitart and her team for the ICP-OES analyses and Concepción Sánchez for the XRD analyses. Luis M. Gandía thanks Banco de Santander and Universidad Pública de Navarra for their financial support under the 'Programa de Intensificación de la Investigación 2018' initiative. Fernando Bimbela and Luis M. Gandía also wish to thank the financial support received from Spanish Ministerio de Ciencia, Innovación y Universidades, and the European Regional Development Fund (ERDF/FEDER) (grant RTI2018-096294-B-C31).

Dry reforming and partial oxidation of biogas were studied using 0.5 wt.% Rh/Al2O3 catalysts, both inhouse prepared and commercial. The effects of O2 addition on syngas yield and biogas conversion were
studied at 700 C using different O2/CH4 ratios in the gas feeding stream: 0 (dry reforming), 0.12, 0.25,
0.45 and 0.50. The highest CH4 conversion, H2 yield and H2/CO molar ratio were obtained with an O2/CH4
ratio of 0.45, even though simultaneous valorization of both CH4 and CO2 could be best attained when the
O2/CH4 ratio was 0.12. Increased biogas conversions and syngas yields were obtained by increasing
reaction temperatures between 650 and 750 C. A detrimental influence on catalytic activity could be
observed when the catalyst was subjected to calcination. Increasing the hold time of the thermal
conditioning of the catalyst under inert flow altered Rh dispersion, though had no significant impact on
catalyst performance in the dry reforming of methane at 700 C and 150 N L CH4/(gcat h). Characterization
of spent samples after reaction by Raman spectroscopy revealed the presence of carbonaceous deposits of
different nature, especially on the commercial(named as Rh com) and calcined (Rh calc) catalysts, though
oxygen addition in the biogas feed significantly reduced the amount of these deposits. The Rh catalysts
that had not been calcined after impregnation (Rh prep) did not present any noticeable characteristic
peaks in the G and D bands. In particular, scanning transmission electron microscopy (STEM) images of
the spent Rh prep sample revealed the presence of very highly dispersed Rh nanoparticles after reaction,
of particle sizes of about 1 nm, and no noticeable C deposits. Combined oxy-CO2 reforming of biogas using
highly dispersed and low metal-loading Rh/Al2O3 catalysts with low O2 dosage in the reactor feed can be
used to effectively transform biogas into syngas., The authors thank the Spanish Ministerio de Economía,
Industria y Competitividad (MINECO) (ENE2015-66975-C3), Spanish Ministerio de Ciencia, Innovación y Universidades (RTI2018-
096294-B-C31), and the European Regional Development Fund
(ERDF/FEDER) for the financial support. MINECO and ERDF/FEDER
are also thanked for the pre-doctoral aid (BES-2016-077866)
awarded to Andrea Navarro and for funding the contract of Dr.
Ainara Moral. The Universidad Pública de Navarra (UPNA) is also
acknowledged for the post-doctoral aid awarded to Inés Reyero.

The success of catalytic schemes for the large-scale valorization of CO2 does not only depend on the development of active, selective and stable catalytic materials but also on the overall process design. Here we present a multidisciplinary study (from catalyst to plant and techno-economic/lifecycle analysis) for the production of green methanol from renewable H2 and CO2. We combine an in-depth kinetic analysis of one of the most promising recently reported methanol-synthesis catalysts (InCo) with a thorough process simulation and techno-economic assessment. We then perform a life cycle assessment of the simulated process to gauge the real environmental impact of green methanol production from CO2. Our results indicate that up to 1.75 ton of CO2 can be abated per ton of produced methanol only if renewable energy is used to run the process, while the sensitivity analysis suggest that either rock-bottom H2 prices (1.5 $ kg−1) or severe CO2 taxation (300 $ per ton) are needed for a profitable methanol plant. Besides, we herein highlight and analyze some critical bottlenecks of the process. Especial attention has been paid to the contribution of H2 to the overall plant costs, CH4 trace formation, and purity and costs of raw gases. In addition to providing important information for policy makers and industrialists, directions for catalyst (and therefore process) improvements are outlined., The authors gratefully acknowledge financial support from the King Abdullah University of Science and Technology (KAUST). T. Cordero-Lanzac and A.T. Aguayo acknowledge the financial support received from the Spanish Ministry of Science and Innovation with some ERDF funds (CTQ2016-77812-R) and the Basque Government (IT1218-19). T. Cordero-Lanzac also acknowledges the Spanish Ministry of Education, Culture and Sport for the award of his FPU grant (FPU15-01666). A. Navajas and L.M. Gandía gratefully acknowledge the financial support from Spanish Ministerio de Ciencia, Innovación y Universidades, and the European Regional Development Fund (ERDF/FEDER) (grant RTI2018-096294-B-C31). L.M. Gandía also thanks Banco de Santander and Universidad Pública de Navarra for their financial support under ‘’Programa de Intensificación de la Investigación 2018’ initiative.

Power-to-methane (PtM) systems may allow fluctuations in the renewable energy supply to be smoothed out by storing surplus energy in the form of methane. These systems work by combining the hydrogen produced by electrolysis with carbon dioxide from different sources to produce methane via the Sabatier reaction. The present work studies PtM systems based on the CO2 supplied by the chemical looping combustion (CLC) of biomass (PtM-bioCLC). Life- cycle- assessment (LCA) was performed on PtM-bioCLC systems to evaluate their environmental impact with respect to a specific reference case. The proposed configurations have the potential to reduce the value of the global warming potential (GWP) climate change indicator to the lowest values reported in the literature to date. Moreover, the possibility of effectively removing CO2 from the atmosphere through the concept of CO2 negative emissions was also assessed. In addition to GWP, as many as 16 LCA indicators were also evaluated and their values for the studied PtM-bioCLC systems were found to be similar to those of the reference case considered or even significantly lower in such categories as resource use-depletion, ozone depletion, human health, acidification potential and eutrophication. The results obtained highlight the potential of these newly proposed PtM schemes., This work was supported by Grant PDC2021-121190-I00 funded by MCIN/AEI/10.13039/501100011033 and by the European Union NextGenerationEU/PRTR and also by Grant PID2020-113131RB-I00 funded by MICIN/AEI/10.13039/501100011033. A.N. and L.M.G. gratefully acknowledge Grant RTI2018-096294-B-C31 funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe”.

Ecuador as an international leader in the production of cocoa beans produced more than 300 000 tons in 2021; hence, the management and valorization of the 2 MM tons of waste generated annually by this industry have a strategic and socioeconomic value. Consequently, appropriate technologies to avoid environmental problems and promote sustainable development and the bioeconomy, especially considering that this is a megadiverse country, are of the utmost relevance. For this reason, we explored a low-cost pyrolysis route for valorizing cocoa pod husks from Ecuador’s Amazonian region, aiming at producing pyrolysis liquids (bio-oil), biochar, and gas as an alternative chemical source from cocoa residues in the absence of hydrogen. Downstream catalytic processing of hot pyrolysis vapors using Mo- and/or Ni-based catalysts and standalone γ-Al2O3 was applied for obtaining upgraded bio-oils in a laboratory-scale fixed bed reactor, at 500 °C in a N2 atmosphere. As a result, bimetallic catalysts increased the bio-oil aqueous phase yield by 6.6%, at the expense of the organic phase due to cracking reactions according to nuclear magnetic resonance (NMR) and gas chromatography–mass spectrometry (GC–MS) results. Overall product yield remained constant, in comparison to pyrolysis without any downstream catalytic treatment (bio-oil ∼39.0–40.0 wt % and permanent gases 24.6–26.6 wt %). Ex situ reduced and passivated MoNi/γ-Al2O3 led to the lowest organic phase and highest aqueous phase yields. The product distribution between the two liquid phases was also modified by the catalytic upgrading experiments carried out, according to heteronuclear single-quantum correlation (HSQC), total correlation spectroscopy (TOCSY), and NMR analyses. The detailed composition distribution reported here shows the chemical production potential of this residue and serves as a starting point for subsequent valorizing technologies and/or processes in the food and nonfood industry beneficiating society, environment, economy, and research., Authors would like to thank the Agencia Española de Cooperación Internacional para el Desarrollo (AECID) and Universidad Regional Amazónica Ikiam for the financial support provided to develop this contribution. The Spanish Ministerio de Ciencia, Innovación y Universidades and the European Regional Development Fund (ERDF/FEDER) are also thanked for providing financial support to the UPNA team (project ref. RTI2018-096294-B-C31). A.C. also thanks the Departamento de Desarrollo Económico del Gobierno de Navarra for the financial support in the “PC036-037 Biovalorización” Project. L.M.G. thanks Banco de Santander and Universidad Pública de Navarra for their financial support under “Programa de Intensificación de la Investigación 2018” initiative. The authors acknowledge the funding from the Aragón Government (ref. T22_17R), cofunded by FEDER 2014-2020 “Construyendo Europa desde Aragón”. K.H. thanks the Universidad Pública de Navarra for the predoctoral aid awarded by the UPNA to do her PhD thesis.

Ash behavior is a key operational aspect of industrial-scale power generation by means of biomass combustion. In this work, FactSage™ 6.4 software was used to develop and assess three models of wheat straw combustion in a vibrating grate-fired commercial boiler of 16 MWth, aiming to describe the inorganic elements release as well as fly ash melting behavior and composition. Simulations were carried out solving four consecutive calculation stages corresponding to the main plant sections. Chemical fractionation was adopted in order to distinguish between reactive, inert and partially reactive biomass fractions. The developed models allow take into account different levels of partial reactivity, values of the temperature for each sub-stage on the grate, and ways to apply entrained streams based on data from the elemental analyses of the fly ashes. To this end, two one-week experimental campaigns were conducted in the plant to carry out the sampling. It has been found that considering chemical fractionation is indispensable to describe the entrainment of solid particles in the gas stream. In addition, the best results are obtained by adopting a small reactivity (2%) of the inert fraction. As for fly ash composition, the concentrations of the major elements showed good agreement with the results from the chemical analyses. In the case of S and Cl, calculations revealed a match with gas cooling effects in the superheaters as well as an entrainment effect. The melting behavior together with the presence of KCl and K2SO4 condensates, point out at possible corrosion phenomena in walls at temperatures of 700–750 °C., This research was funded by the Spanish Ministerio de Economía y Competitividad (MINECO), in accordance with the provisions of article 31 Regulation of Law 38/2003, of November 17, General Subsidies, approved by Royal Decree 887/2006, of July 21. Funding was received within the framework of the MULTIBOM (Development of Multi-fuel Biomass Combustion Technology for High-Power Electrical Production) project, which has received public funding from the INNPACTO subprogramme (Prj. Re. num. IPT-2012-0155-120000). Luis M. Gandía thanks Banco de Santander and Universidad Pública de Navarra for their financial support under 'Programa de Intensificación de la Investigación 2018' initiative, as well as Spanish Ministerio de Ciencia, Innovación y Universidades and the European Regional Development Fund (ERDF/FEDER) (grant RTI2018-096294-B-C31).

The use of biomass for the production of energy and higher added value products is a topic of increasing interest in line with growing environmental concerns and circular economy. Mesoporous material Sn-In-MCM-41 was synthesized for the first time and used as a catalyst for the transformation of sugars to methyl lactate (ML). This catalyst was characterized in depth by various techniques and compared with Sn-MCM-41 and In-MCM-41 catalysts. In the new Sn-In-MCM-41 material, both metals, homogeneously distributed throughout the mesoporous structure of MCM-41, actuate in a cooperative way in the different steps of the reaction mechanism. As a result, yields to ML of 69.4 and 73.9% in the transformation of glucose and sucrose were respectively reached. In the case of glucose, the ML yield 1.5 and 2.6 times higher than those of Sn-MCM-41 and In-MCM-41 catalysts, respectively. The Sn-In-MCM-41 catalyst was reused in the transformation of glucose up to four cycles without significant loss of catalytic activity. Finally, life cycle assessment comparison between chemical and biochemical routes to produce ML allowed us to conclude that the use of Sn-In-MCM-41 reduces the environmental impacts compared to Sn-MCM-41. Nevertheless, to make the chemical route comparable to the biochemical one, improvements in the catalyst and ML synthesis have to be achieved., Financial support from the Grant MAT2016-77290-R funded by MCIN/AEI/10.13039/501100011033 and by 'ERDF A way of making Europe', and Grant T43-20R funded by the Aragón Government are gratefully acknowledged. A.N. and L.M.G. gratefully acknowledge the financial support from Spanish Ministerio de Ciencia, Innovación y Universidades, and the Grant RTI2018-096294-B-C31 funded by ERDF/FEDER. L.M.G. also thanks Banco Santander and Universidad Pública de Navarra for their financial support under 'Programa de Intensificación de la Investigación 2018' initiative.

Reproducible and controllable incorporation and immobilization of catalysts and other active particles onto silicone microreactor channels is still challenging. In this work, we present an innovative fabrication protocol to attain affordable, custom-designed photocatalytic microreactors in a fast and simple manner. In this protocol, a 3D-printed ABS microreactor mold is first dip-coated with the photocatalyst, and subsequently, the catalytic layer is transferred onto the microchannel walls by indirect immobilization during the silicone casting and scaffold removal step. Serpentine-shaped microreactors have been satisfactorily fabricated with Au@POM-impregnated TiO2 nanoparticles (Au@POM/TiO2; Au 0.18 % w/w, POM: H3PW12O40) as the integrated photocatalytic layer. The suitability of our fabrication method has been validated on the basis of the excellent photocatalytic performance shown by the microreactors in a model test reaction such as the continuous-flow photoreduction of 4-nitrophenol to 4-aminophenol with NaBH4 and monitored by UV-Vis spectroscopy., Financial support from Gobierno de Navarra (grants PC025-26 and PI030) an Spanish Ministerio de Ciencia, Innovación y Universidades, and the European Regional Development Fund (ERDF/FEDER) (grant RTI2018-096294-B-C31) is gratefully acknowledged. I.P. and S.R. thank Obra Social la Caixa, Fundación Caja Navarra and Universidad Pública de Navarra (UPNA) for their research contracts in the framework of the programs 'Ayudas Postdoctorales' and 'Captación del Talento'. L.M.G. thanks Banco de Santander and UPNA for their financial support under 'Programa de Intensificación de la Investigación 2018' initiative. Centro Tecnológico Lurederra is gratefully acknowledged for its partnership in the project FOREST (PC025-026).

Washcoating and packing of Co-Re catalyst particles have been employed as structuring methods of parallel channel monoliths used in the low-temperature Fischer-Tropsch synthesis (FTS). These methods were compared with regard to catalyst hold-up, heat transfer properties and pressure drop. Reactors output was assessed in terms of CO conversion, CH4 selectivity and productivity of C5+ hydrocarbons. Washcoating led to much lower pressure drops, but also resulted in considerably lower catalyst inventory. As for the reactors performance (volumetric and per catalyst mass C5+ productivities), the washcoated monoliths were more effective than the packed-bed ones. This has been attributed to their more favorable hydrodynamic behavior that facilitates the drainage of the reaction products (liquids and waxes) through the central hollow of the channels thus reducing the extra-pellet diffusional limitations. For both catalyst configurations, it has been found that the productivity of C5+ per catalyst mass unit increases as the characteristic diffusion length increases within the range of values considered in this study (below 150 µm). This indicates that a moderate level of internal mass transport restrictions is beneficial for the low-temperature FTS, which has been explained in terms of the effects of diffusional limitations on the H2/CO molar ratio, and that of this ratio on the FTS kinetics. The possible influence of thermal effects on these results has been numerically and experimentally discarded., Financial support of this work was undertaken by the Basque Government (IT1069-16) and the Spanish Ministerio de Ciencia, Innovación y Universidades and the European Regional Development Fund (ERDF/FEDER) (grants RTI2018-096294-B-C31, RTI2018-096294-B-C32 and CTQ2015-73901-JIN). Open Access funding provided by University of Basque Country. Luis M. Gandía wishes to thank Banco de Santander and Universidad Pública de Navarra for their financial support under the 'Programa de Intensificación de la Investigación 2018' initiative.

8 figures, 5 tables.-- Supplementary information available., Power-to-methane (PtM) systems may allow fluctuations in the renewable energy supply to be smoothed out by storing surplus energy in the form of methane. These systems work by combining the hydrogen produced by electrolysis with carbon dioxide from different sources to produce methane via the Sabatier reaction. The present work studies PtM systems based on the CO supplied by the chemical looping combustion (CLC) of biomass (PtM-bioCLC). Life- cycle- assessment (LCA) was performed on PtM-bioCLC systems to evaluate their environmental impact with respect to a specific reference case. The proposed configurations have the potential to reduce the value of the global warming potential (GWP) climate change indicator to the lowest values reported in the literature to date. Moreover, the possibility of effectively removing CO from the atmosphere through the concept of CO negative emissions was also assessed. In addition to GWP, as many as 16 LCA indicators were also evaluated and their values for the studied PtM-bioCLC systems were found to be similar to those of the reference case considered or even significantly lower in such categories as resource use-depletion, ozone depletion, human health, acidification potential and eutrophication. The results obtained highlight the potential of these newly proposed PtM schemes., This work was supported by Grant PDC2021-121190-I00 funded by MCIN/AEI/10.13039/501100011033 and by the European Union NextGenerationEU/PRTR and also by Grant PID2020-113131RB-I00 funded by MICIN/AEI/10.13039/501100011033. A.N. and L.M.G. gratefully acknowledge Grant RTI2018-096294-B-C31 funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe”., Peer reviewed

The use of biomass for the production of energy and higher added value products is a topic of increasing interest in line with growing environmental concerns and circular economy. Mesoporous material Sn-In-MCM-41 was synthesized for the first time and used as a catalyst for the transformation of sugars to methyl lactate (ML). This catalyst was characterized in depth by various techniques and compared with Sn-MCM-41 and In-MCM-41 catalysts. In the new Sn-In-MCM-41 material, both metals, homogeneously distributed throughout the mesoporous structure of MCM-41, actuate in a cooperative way in the different steps of the reaction mechanism. As a result, yields to ML of 69.4 and 73.9% in the transformation of glucose and sucrose were respectively reached. In the case of glucose, the ML yield 1.5 and 2.6 times higher than those of Sn-MCM-41 and In-MCM-41 catalysts, respectively. The Sn-In-MCM-41 catalyst was reused in the transformation of glucose up to four cycles without significant loss of catalytic activity. Finally, life cycle assessment comparison between chemical and biochemical routes to produce ML allowed us to conclude that the use of Sn-In-MCM-41 reduces the environmental impacts compared to Sn-MCM-41. Nevertheless, to make the chemical route comparable to the biochemical one, improvements in the catalyst and ML synthesis have to be achieved., Financial support from the Grant MAT2016-77290-R funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”, and Grant T43-20R funded by the Aragón Government are gratefully acknowledged. The authors would like to acknowledge Dr. Elena Serrano from Centro Universitario de la Defensa Zaragoza for her contribution (preparation of materials and solutions for titration of catalysts) in this work. The authors would like to acknowledge the use of the Servicio General de Apoyo a la Investigación-SAI and the use of instrumentation as well as the technical advice provided by the National Facility ELECMI ICTS, node “Laboratorio de Microscopias Avanzadas” at the University of Zaragoza. A.N. and L.M.G. gratefully acknowledge the financial support from Spanish Ministerio de Ciencia, Innovación y Universidades, and the Grant RTI2018-096294-B-C31 funded by ERDF/FEDER. L.M.G. also thanks Banco Santander and Universidad Pública de Navarra for their financial support under “Programa de Intensificación de la Investigación 2018” initiative., Peer reviewed

Acrylonitrile butadiene styrene (ABS) is one of the most extensively used polymer in 3D printing manufacturing due to its competitive thermal and mechanical properties. Recently, a special attention has been devoted to novel ABS composites featuring extra functionalities e.g. in the area of VOC removal. Herein, we report on a facile protocol for the functionalization of 3D printed ABS filters with a MOF (Metal-Organic Framework) material (ZIF-8) targeting the conception of attractive gas filters. The proposed synthesis strategy consists in low temperature ALD (Atomic Layer Deposition) of ZnO on the ABS grid followed by the hydrothermal conversion of ZnO to ZIF-8, both steps being conducted at 60 °C. In such way, the method enables an effective growth of ZIF-8 without altering the stability of the polymeric ABS support. The as-fabricated ABS/ZIF-8 filters offer a promising adsorption behaviour for dimethyl methylphosphonate (∼20.4 mg of DMMP per gram of ZIF-8), thus proving their potential for toxic gas capture applications., Financial support from Gobierno de Navarra (grants PC052-23), from MINECO (grant
CTQ2016-79419-R) and from the Spanish Ministerio de Ciencia, Innovación y Universidades and the European Regional Development Fund (ERDF/FEDER) (grant
RTI2018-096294-B-C31) is gratefully acknowledged. I. P. thanks Obra Social la Caixa, Fundación Caja Navarra and UPNA for his research contracts in the framework of the programs “Ayudas Postdoctorales” and “Captación Talento”. L. M. G. wishes to thank Banco de Santander and Universidad Pública de Navarra for their financial support under “Programa de Intensificación de la Investigación 2018” initiative., Peer reviewed

Ecuador as an international leader in the production of cocoa beans produced more than 300 000 tons in 2021; hence, the management and valorization of the 2 MM tons of waste generated annually by this industry have a strategic and socioeconomic value. Consequently, appropriate technologies to avoid environmental problems and promote sustainable development and the bioeconomy, especially considering that this is a megadiverse country, are of the utmost relevance. For this reason, we explored a low-cost pyrolysis route for valorizing cocoa pod husks from Ecuador’s Amazonian region, aiming at producing pyrolysis liquids (bio-oil), biochar, and gas as an alternative chemical source from cocoa residues in the absence of hydrogen. Downstream catalytic processing of hot pyrolysis vapors using Mo- and/or Ni-based catalysts and standalone γ-Al2O3 was applied for obtaining upgraded bio-oils in a laboratory-scale fixed bed reactor, at 500 °C in a N2 atmosphere. As a result, bimetallic catalysts increased the bio-oil aqueous phase yield by 6.6%, at the expense of the organic phase due to cracking reactions according to nuclear magnetic resonance (NMR) and gas chromatography–mass spectrometry (GC–MS) results. Overall product yield remained constant, in comparison to pyrolysis without any downstream catalytic treatment (bio-oil ∼39.0–40.0 wt % and permanent gases 24.6–26.6 wt %). Ex situ reduced and passivated MoNi/γ-Al2O3 led to the lowest organic phase and highest aqueous phase yields. The product distribution between the two liquid phases was also modified by the catalytic upgrading experiments carried out, according to heteronuclear single-quantum correlation (HSQC), total correlation spectroscopy (TOCSY), and NMR analyses. The detailed composition distribution reported here shows the chemical production potential of this residue and serves as a starting point for subsequent valorizing technologies and/or processes in the food and nonfood industry beneficiating society, environment, economy, and research.