The oil extraction process generates about 70,000 tons of alperujo, which is organic waste that is currently used directly as fertilizer and to a lesser extent as fuel, due to its high humidity.
The Universidad de Concepción, through the Technological Development Unit (UDT), is making progress in creating activated carbons and biofuel from olive oil industry waste. The innovation, supported by the Foundation for Agricultural Innovation (FIA), seeks to modernize the industry towards intelligent production processes, in the path of the Circular Bioeconomy.
In Chile there are about 25,000 hectares of olive trees, which produce 17,500 tons of oil per year for the domestic and international market. The oil extraction process generates about 70,000 tons of alperujo (pressed in 2 phases) and orujo (in 3 phases), which are organic wastes that are currently used directly as fertilizer and to a lesser extent as fuel, due to their high humidity.
Thus, Universidad de Concepción, through the Technological Development Unit, UDT, is executing the project supported by the Foundation for Agrarian Innovation (FIA), “Innovative solution for the valorization of olive oil industry waste: Development of activated carbons and biofuel”, which proposes the integral valorization of waste through the development of activated carbons, taking advantage of the intrinsic characteristics of the olive pit, and the production of solid biofuels using the alperujo and/or pomace.
PROCESS
The initiative started in September 2019, and although it had some delays due to the pandemic, it has been able to show several results this year. Dr. Cristina Segura, director of the project, indicates that “raw materials from three-phase (pomace) and two-phase (alperujo) olive mills were characterized in addition to olive pits, which are the residues from olive oil extraction and have a high moisture content of 60-70%. The analysis showed that the pomace/alperujo showed a high calorific value compared to olive stone and lignocellulosic biomass and a moderate ash content. The main drawback is its nitrogen content, which exceeds the levels suggested by the Chilean standard for solid biofuels”.
Then, an experimental study of pellet production from pomace and alperujo showed that the oil content of these residues makes it difficult to compact them in a pelletizing press, as they act as a lubricant. To try to solve this problem, mixtures of pomace and/or alperujo were made with residual lignocellulosic biomass (pine and eucalyptus) and also with olive pits. “It was possible to produce pellets with 40/60 mixtures of olive pomace/wood biomass, with good mechanical durability and with ash and nitrogen levels within the ranges required for wood pellets for residential use, according to the requirements established in the NCh-ISO 17225-2 Standard,” explained Dr. Segura.
With respect to the synthesis of activated carbons, which are used as adsorbent materials in odor removal systems of industrial gas currents and/or in water cleaning filters, studies were carried out at laboratory level of olive pit activation using physical methods (with high temperature steam and CO2) and chemical methods (with phosphoric acid H3PO4 and potassium hydroxide KOH) “The results showed that under the best conditions activated carbons were achieved with surface areas between 1000 and 1500 m2/g for physical activation and between 1800-1980 m2/g for chemical activation, comparable with commercial activated carbons of high commercial value, which is very promising for the applications envisaged,” said Cristina Segura.
PROCESS
The initiative began in September 2019, and although it had some delays due to the pandemic, it has been able to show several results this year. Dr. Cristina Segura, director of the project, indicates that “raw materials from three-phase (pomace) and two-phase (alperujo) olive mills were characterized, in addition to olive pits, which are the residues from olive oil extraction and have a high moisture content of 60-70%. The analysis showed that the pomace/alperujo showed a high calorific value compared to olive stone and lignocellulosic biomass and a moderate ash content. The main drawback is its nitrogen content, which exceeds the levels suggested by the Chilean standard for solid biofuels”.
Then, an experimental study of pellet production from pomace and alperujo showed that the oil content of these residues makes it difficult to compact them in a pelletizing press, as they act as a lubricant. To try to solve this problem, mixtures of pomace and/or alperujo were made with residual lignocellulosic biomass (pine and eucalyptus) and also with olive pits. “It was possible to produce pellets with 40/60 mixtures of olive pomace/wood biomass, with good mechanical durability and with ash and nitrogen levels within the ranges required for wood pellets for residential use, according to the requirements established in the NCh-ISO 17225-2 Standard,” explained Dr. Segura.
With respect to the synthesis of activated carbons, which are used as adsorbent materials in odor removal systems of industrial gas currents and/or in water cleaning filters, studies were carried out at laboratory level of olive pit activation using physical methods (with high temperature steam and CO2) and chemical methods (with phosphoric acid H3PO4 and potassium hydroxide KOH) “The results showed that under the best conditions activated carbons were achieved with surface areas between 1000 and 1500 m2/g for physical activation and between 1800-1980 m2/g for chemical activation, comparable with commercial activated carbons of high commercial value, which is very promising for the applications envisaged,” said Cristina Segura.
EFFECT
Both proposals, to develop activated carbons and a densified, low-moisture solid fuel from olive oil industry residues, are innovative technological alternatives that can contribute to the sustainability, innovation and competitiveness of SMEs in the sector. In the case of pellets, as biofuel (energy, heating); and activated carbons as adsorbents and decontaminants of water and odors in industrial gas streams.
Along these lines, Álvaro Eyzaguirre Pepper, executive director of the Foundation for Agricultural Innovation (FIA), said that “in the Biobío region and at the national level, it is necessary to continue promoting innovative processes to make sustainability a key factor in all activities, which is why initiatives such as these are presented as an alternative to promote the importance of sustainability due to climate change and water scarcity that agriculture is facing today. Through innovation, initiatives based on sustainable production management can be developed to mitigate climate change, also promoting projects related to circular economy, efficient use of natural resources, soil and grassland management that promote carbon sequestration. In this sense, the development of the circular bioeconomy can be achieved through innovation, and for this it is extremely important to have information, networks, training and, of course, financing to incorporate more initiatives in these areas.
The management and final use of these wastes poses environmental problems associated with odors and negative effects on plantations, so companies need to make progress on sustainability issues in order to be able to target international markets, which are highly competitive. It is also necessary to incorporate innovation to move towards intelligent production processes, along the path of the Circular Bioeconomy.