{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,3]],"date-time":"2026-03-03T00:32:24Z","timestamp":1772497944034,"version":"3.50.1"},"reference-count":39,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2020,6,1]],"date-time":"2020-06-01T00:00:00Z","timestamp":1590969600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Recycling"],"abstract":"<jats:p>The demand for new sources of energy is one of the main quests for humans. At the same time, there is a growing need to eliminate or recover a set of industrial or agroforestry waste sources. In this context, several options may be of interest, especially given the amounts produced and environmental impacts caused. Olive pomace can be considered one of these options. Portugal, as one of the most prominent producers of olive oil, therefore, also faces the problem of dealing with the waste of the olive oil industry. Olive pomace energy recovery is a subject referenced in many different studies and reports since long ago. However, traditional forms of recovery, such as direct combustion, did not prove to be the best solution, mainly due to its fuel properties and other characteristics, which cause difficulties in its storage and transportation as well. Torrefaction and pyrolysis can contribute to a volume reduction, optimizing storage and transportation. In this preliminary study, were carried out torrefaction and pyrolysis tests on olive pomace samples, processed at 300 \u00b0C, 400 \u00b0C, and 500 \u00b0C, followed by laboratory characterization of the materials. It was verified an improvement in the energy content of the materials, demonstrating that there is potential for the use of these thermochemical conversion technologies for the energy recovery of olive pomace.<\/jats:p>","DOI":"10.3390\/recycling5020012","type":"journal-article","created":{"date-parts":[[2020,6,2]],"date-time":"2020-06-02T04:09:03Z","timestamp":1591070943000},"page":"12","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["Thermochemical Conversion of Olive Oil Industry Waste: Circular Economy through Energy Recovery"],"prefix":"10.3390","volume":"5","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5404-8163","authenticated-orcid":false,"given":"Leonel J. R.","family":"Nunes","sequence":"first","affiliation":[{"name":"PROMETHEUS\u2014Unidade de Investiga\u00e7\u00e3o em Materiais, Energia e Ambiente para a Sustentabilidade, Escola Superior Agr\u00e1ria, Instituto Polit\u00e9cnico de Viana do Castelo, Rua da Escola Industrial e Comercial de Nun\u2019Alvares, 4900-347 Viana do Castelo, Portugal"},{"name":"GOVCOPP\u2014Unidade de Investiga\u00e7\u00e3o em Governan\u00e7a, Competitividade e Pol\u00edticas P\u00fablicas, DEGEIT\u2014Departamento de Economia, Gest\u00e3o, Engenharia Industrial e Turismo, Universidade de Aveiro, Campus Universit\u00e1rio de Santiago, 3810-193 Aveiro, Portugal"}]},{"given":"Liliana M. E. F.","family":"Loureiro","sequence":"additional","affiliation":[{"name":"YGE\u2014Yser Green Energy SA, \u00c1rea de Acolhimento Empresarial de \u00dal\/Loureiro, Lote 17, 3720-075 Loureiro OAZ, Portugal"}]},{"given":"Let\u00edcia C. R.","family":"S\u00e1","sequence":"additional","affiliation":[{"name":"YGE\u2014Yser Green Energy SA, \u00c1rea de Acolhimento Empresarial de \u00dal\/Loureiro, Lote 17, 3720-075 Loureiro OAZ, Portugal"}]},{"given":"Hugo F.C.","family":"Silva","sequence":"additional","affiliation":[{"name":"AFS\u2014Advanced Fuel Solutions SA, \u00c1rea de Acolhimento Empresarial de \u00dal\/Loureiro, Lote 17, 3720-075 Loureiro OAZ, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2020,6,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"541","DOI":"10.1016\/S0024-3205(97)01150-8","article-title":"Oleuropein, the bitter principle of olives, enhances nitric oxide production by mouse macrophages","volume":"62","author":"Visioli","year":"1998","journal-title":"Life Sci."},{"key":"ref_2","first-page":"49","article-title":"Uncovering Production Flows from Small Farms: Results from Poland and Portugal Case Studies","volume":"21","author":"Czekaj","year":"2019","journal-title":"Rocz. Nauk. Stowarzyszenia Ekon. Rol. I Agrobiz."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"120276","DOI":"10.1016\/j.talanta.2019.120276","article-title":"Revisiting 3D van Krevelen diagrams as a tool for the visualization of volatile profile of varietal olive oils from Alentejo region, Portugal","volume":"207","author":"Martins","year":"2020","journal-title":"Talanta"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"209","DOI":"10.1080\/10643380490279932","article-title":"A review of waste management options in olive oil production","volume":"34","author":"Azbar","year":"2004","journal-title":"Crit. Rev. Environ. Sci. Technol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"704","DOI":"10.1016\/j.foodchem.2011.03.092","article-title":"Valorization of olive oil solid waste using high pressure\u2013high temperature reactor","volume":"128","author":"Aliakbarian","year":"2011","journal-title":"Food Chem."},{"key":"ref_6","first-page":"613","article-title":"Solid state fermentation of waste pomace from olive processing","volume":"74","author":"Haddadin","year":"1999","journal-title":"J. Chem. Technol. Biotechnol. Int. Res. Process Environ. Clean Technol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"960","DOI":"10.1016\/j.wasman.2005.07.024","article-title":"An overview on olive mill wastes and their valorisation methods","volume":"26","author":"Roig","year":"2006","journal-title":"Waste Manag."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"521","DOI":"10.1051\/agro:2008027","article-title":"Improvement of soil properties by application of olive oil waste","volume":"28","author":"Cucci","year":"2008","journal-title":"Agron. Sustain. Dev."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"7982","DOI":"10.1016\/j.biortech.2008.03.051","article-title":"Short and medium-term effects of two-phase olive mill waste application on olive grove production and soil properties under semiarid Mediterranean conditions","volume":"99","author":"Nunes","year":"2008","journal-title":"Bioresour. Technol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"36204","DOI":"10.1155\/2007\/36204","article-title":"Antithrombotic and antiatherosclerotic properties of olive oil and olive pomace polar extracts in rabbits","volume":"2007","author":"Tsantila","year":"2007","journal-title":"Mediat. Inflamm."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1007\/s00253-008-1801-y","article-title":"Bioremediation and biovalorisation of olive-mill wastes","volume":"82","author":"Morillo","year":"2009","journal-title":"Appl. Microbiol. Biotechnol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1007\/s10532-017-9782-0","article-title":"Advanced oxidation process and biological treatments for table olive processing wastewaters: Constraints and a novel approach to integrated recycling process: A review","volume":"28","author":"Ayed","year":"2017","journal-title":"Biodegradation"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"68","DOI":"10.1016\/j.tifs.2012.03.003","article-title":"Recovery of high added-value components from food wastes: Conventional, emerging technologies and commercialized applications","volume":"26","author":"Galanakis","year":"2012","journal-title":"Trends Food Sci. Technol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"132","DOI":"10.1016\/j.seppur.2005.11.016","article-title":"Sorption of Pb (II), Ni (II), Cu (II) and Cd (II) from aqueous solution by olive stone waste","volume":"50","author":"Fiol","year":"2006","journal-title":"Sep. Purif. Technol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1016\/j.jhazmat.2009.12.047","article-title":"Adsorption of methylene blue on low-cost adsorbents: A review","volume":"177","author":"Rafatullah","year":"2010","journal-title":"J. Hazard. Mater."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Nunes, L.J. (2020). A Case Study about Biomass Torrefaction on an Industrial Scale: Solutions to Problems Related to Self-Heating, Difficulties in Pelletizing, and Excessive Wear of Production Equipment. Appl. Sci., 10.","DOI":"10.3390\/app10072546"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Nunes, L., Matias, J., and Catal\u00e3o, J. (2016, January 6\u20139). Torrefied Biomass Pellets: An alternative fuel for coal power plants. Proceedings of the 2016 13th International Conference on the European Energy Market (EEM), Porto, Portugal.","DOI":"10.1109\/EEM.2016.7521316"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1016\/j.powtec.2019.08.058","article-title":"Fluidized bed torrefaction of biomass pellets: A comparison between oxidative and inert atmosphere","volume":"357","author":"Brachi","year":"2019","journal-title":"Powder Technol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"624","DOI":"10.1016\/j.renene.2019.04.068","article-title":"Torrefaction of biomass: A review of production methods for biocoal from cultured and waste linocellulosic feedstocks","volume":"142","author":"Barskov","year":"2019","journal-title":"Renew. Energy"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"453","DOI":"10.1016\/j.energy.2016.04.034","article-title":"Combustion characteristics and kinetics of torrefied olive pomace","volume":"107","author":"Guizani","year":"2016","journal-title":"Energy"},{"key":"ref_21","first-page":"6286","article-title":"Effects of torrefaction on carbonization characteristics of solid olive mill residue","volume":"11","year":"2016","journal-title":"BioResources"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Ribeiro, J.M.C., Godina, R., Matias, J.C.d.O., and Nunes, L.J.R. (2018). Future perspectives of biomass torrefaction: Review of the current state-of-the-art and research development. Sustainability, 10.","DOI":"10.3390\/su10072323"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"S\u00e1, L.C., Loureiro, L.M., Nunes, L.J., and Mendes, A.M. (2020). Torrefaction as a pretreatment technology for chlorine elimination from biomass: A case study using Eucalyptus globulus Labill. Resources, 9.","DOI":"10.3390\/resources9050054"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"487","DOI":"10.1016\/j.fuel.2004.10.010","article-title":"A correlation for calculating HHV from proximate analysis of solid fuels","volume":"84","author":"Parikh","year":"2005","journal-title":"Fuel"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1016\/j.fuproc.2011.10.016","article-title":"Characterization and combustion of olive pomace and forest residue pellets","volume":"103","author":"Miranda","year":"2012","journal-title":"Fuel Process. Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"323","DOI":"10.1016\/j.wasman.2015.11.042","article-title":"Use of bottom ash from olive pomace combustion in the production of eco-friendly fired clay bricks","volume":"48","year":"2016","journal-title":"Waste Manag."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"18349","DOI":"10.3390\/ijms151018349","article-title":"Control of several emissions during olive pomace thermal degradation","volume":"15","author":"Miranda","year":"2014","journal-title":"Int. J. Mol. Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1459","DOI":"10.1016\/j.fuproc.2010.05.023","article-title":"Emissions from thermal degradation of pellets with different contents of olive waste and forest residues","volume":"91","author":"Miranda","year":"2010","journal-title":"Fuel Process. Technol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.scitotenv.2019.01.210","article-title":"Three different methods for turning olive pomace in resource: Benefits of the end products for agricultural purpose","volume":"662","author":"Muscolo","year":"2019","journal-title":"Sci. Total Environ."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1227","DOI":"10.1016\/j.rser.2015.12.196","article-title":"Economic analysis and energy valorization of by-products of the olive oil process:\u201cValdemone DOP\u201d extra virgin olive oil","volume":"57","author":"Lanfranchi","year":"2016","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"222","DOI":"10.1016\/j.jaap.2015.06.002","article-title":"Nitrogen products and reaction pathway of nitrogen compounds during the pyrolysis of various organic wastes","volume":"114","author":"Debono","year":"2015","journal-title":"J. Anal. Appl. Pyrolysis"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"5088","DOI":"10.1021\/acs.energyfuels.5b00792","article-title":"Nitrogen transformation during sewage sludge pyrolysis","volume":"29","author":"Wei","year":"2015","journal-title":"Energy Fuels"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"8443","DOI":"10.1016\/j.chroma.2011.09.055","article-title":"Analysis of cyclic pyrolysis products formed from amino acid monomer","volume":"1218","author":"Choi","year":"2011","journal-title":"J. Chromatogr. A"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"844","DOI":"10.1016\/j.fuel.2007.05.041","article-title":"Torrefaction of reed canary grass, wheat straw and willow to enhance solid fuel qualities and combustion properties","volume":"87","author":"Bridgeman","year":"2008","journal-title":"Fuel"},{"key":"ref_35","unstructured":"Bergman, P.C., and Kiel, J.H. (2005, January 17\u201321). Torrefaction for biomass upgrading. Proceedings of the 14th European Biomass Conference, Paris, France."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1016\/S0973-0826(08)60519-0","article-title":"Wood briquette torrefaction","volume":"9","author":"Felfli","year":"2005","journal-title":"Energy Sustain. Dev."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"649","DOI":"10.1002\/ep.11827","article-title":"Pyrolysis of olive pomace and copyrolysis of olive pomace with refuse derived fuel","volume":"33","author":"Aydemir","year":"2014","journal-title":"Environ. Prog. Sustain. Energy"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"119","DOI":"10.1016\/j.energy.2015.01.011","article-title":"Assessment of olive wastes as energy source: Pyrolysis, torrefaction and the key role of H loss in thermal breakdown","volume":"82","author":"Volpe","year":"2015","journal-title":"Energy"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"11234","DOI":"10.1016\/j.biortech.2011.09.010","article-title":"Pyrolysis of olive residue and sugar cane bagasse: Non-isothermal thermogravimetric kinetic analysis","volume":"102","author":"Ounas","year":"2011","journal-title":"Bioresour. Technol."}],"container-title":["Recycling"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2313-4321\/5\/2\/12\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:34:40Z","timestamp":1760175280000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2313-4321\/5\/2\/12"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,6,1]]},"references-count":39,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2020,6]]}},"alternative-id":["recycling5020012"],"URL":"https:\/\/doi.org\/10.3390\/recycling5020012","relation":{},"ISSN":["2313-4321"],"issn-type":[{"value":"2313-4321","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,6,1]]}}}