Percorrer por autor "Smolich, Camilla Groxko"
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- Dry purification of ethanolic biodiesel produced from waste cooking oils through adsorption processesPublication . Smolich, Camilla Groxko; Brito, Paulo; Queiroz, Ana; Ribeiro, António E.; Gomes, Maria Carolina SérgiDue to the risk of possible depletion of fossil fuels and the increasing consumption of energy from renewable energy sources, biodiesel emerges as an alternative to non-renewable fuel. An important stage in its production process is purification, commonly done through wet washing to remove glycerol in solution. However, this method consumes large volumes of water, resulting in significant effluent volumes. Therefore, this study aimed to apply adsorption as an alternative method. To apply this method, the chosen agroindustrial waste was olive pit, as it is widely produced in Portugal and was implemented in the form of activated carbon. The overall process involved three main stages: biodiesel and activated carbon production, subsequent characterization, and adsorption tests for glycerol removal. Biodiesel was produced through transesterification of waste cooking oil under specific conditions, resulting in a sample with high glycerol content, incomplete conversion to fatty acid esters, and high in linoleic acid ethyl ester, indicating the presence of sunflower oil. The activated carbon was produced from dry olive pits and showed basic characteristics, suitable for glycerol removal. Adsorption kinetic tests revealed that the activated carbon was favorable in removing glycerol from the biodiesel, with the best result achieved at 25°C after 1440 minutes, reaching 89.7% glycerol removal. The isotherm models used in the study showed favorable results, indicating that adsorption occurred in a multilayer formation and on a heterogeneous surface. However, the study concluded that while the activated carbon contributes to biodiesel purification, it cannot completely substitute wet washing due to the inability to achieve the required glycerol content limit in a single stage process. In the future, other conditions may be added to this work, for example: use different kinds of WCO, different activations of the adsorbent, different transesterification conditions, recycle AC, and change the purification from batch to continuous process. The study's results provide valuable insights into the potential of olive pits activated carbon for biodiesel purification and the limitations of its use as a complete substitute for wet washing
- Production of biodiesel from waste cooking oils and its purification using adsorption techniques with natural adsorbentsPublication . Fabian, João Vitor; Guimarães, Miriam D.; Smolich, Camilla Groxko; Pokriwiecki, Ticiane S.; Queiroz, Ana; Ribeiro, António E.; Brito, PauloThe world's energy demands are steadily increasing each year, promoting the exploration of cleaner and more sustainable alternatives to classical fossil sources. In this context, biodiesel emerges as a promising candidate for replacing fossil diesel, making a significant contribution to carbon emissions reduction. One notable advantage lies in the ability to utilize waste cooking oils (WCO) as a feedstock for biodiesel production. This practice not only mitigates waste but also transforms a previously underutilized resource into a valuable source of renewable energy, thereby promoting sustainability and energy efficiency. Currently, 95% of biodiesel production relies on first-hand feedstock due to its high conversion into fatty acid ethyl esters (FAEEs) or fatty acid methyl esters (FAMEs) . However, this study introduces the utilization of Waste Cooking Oil (WCO) as a greener approach to biodiesel production. Biodiesel production can be achieved through alkaline catalyzed transesterification, with the aim of meeting the standards specified by EN 14214 at the end of its production process. Therefore, crude biodiesel obtained from the transesterification step needs to undergo glycerol purification in order to comply with the norm specification of a maximum free glycerin content of 0.02% (w/w). Hence, the present study seeks to produce and characterize activated carbons derived from walnut shells, and evaluate its use in the removal of glycerol from crude ethanolic biodiesel produced from WCO, a possible alternative to the traditional wet washing process, which results in the loss of between 0.2L to 10L of water per liter of biodiesel produced . In this work, titration in triplicate was employed to determine the acid value of the oil, quantified as mg KOH/g of the sample, yielding a result of 0.8355±0.0274. This provided a preliminary assessment for the determination of the necessary alkaline catalyst percentage which would mitigate parallel saponification during the transesterification process. The reaction tests, executed in duplicate, included varying catalyst proportions of 0.5%, 0.6%, and 0.7% (w/w) relative to the processed oil. Gas chromatography (GC) was employed for the characterization of the produced biodiesel, revealing that a 0.5% (w/w) catalyst load was the optimal choice, providing a consistent average yield of 89.52% in FAEEs. Biodiesel production is currently conducted via the ethanol route with 1:7.5 oil/ethanol molar ratio, considering an excess in relation to the stoichiometric molar ratio 1:3. The research is also focused on the production of activated carbon materials, involving both chemical and physical activation techniques. Chemical activations will encompass the utilization of bases (KOH), acids (H3PO4), constituting a pivotal phase in enhancing the overall efficiency and sustainability of the biodiesel production process.
- Purification of biodiesel produced from used cooking oil using natural-origin adsorbentsPublication . Guimarães, Miriam D.; Smolich, Camilla Groxko; Fabian, João Vitor; De Prá, Marina Celant; Queiroz, Ana; Brito, Paulo; Ribeiro, António E.Biodiesel is a biofuel with significant potential to replace conventional diesel. It is obtained through a transesterification reaction between oil and alcohol, in the presence of a catalyst. At the end of this reaction, a decantation process is carried out, forming two phases: the upper phase, which is biodiesel, and the lower phase, which is rich in glycerol. Before being used, biodiesel must undergo a purification process to remove glycerin residues and other contaminants . This purification step plays a crucial role in the biodiesel production chain. Among the most common processes are water washing, the use of ion exchange resins, and adsorbents. The use of adsorbents in biodiesel purification eliminates the need for water, thereby avoiding the generation of effluents, and the adsorbents can be reused. Adsorbents function to remove contaminants, such as water, soap, and traces of glycerin, based on their chemical polarities and acidic and basic properties . The use of commercial adsorbents has a significant economic impact due to the increased production costs and environmental concerns regarding their final disposal when saturated. One solution to this problem is the use of natural adsorbents, which are biodegradable and often derived from agro-industrial waste, such as wood, water hyacinth, food, coconut fiber, pecan nutshells, among others. The use of natural adsorbents can occur in two ways: in their natural state or through the production of activated carbon materials which contain a variety of compounds, with carbon as its main constituent. Although it does not have a specific morphology, it has a high surface area and porosity. It is a widely used adsorbent due to its effectiveness in removing contaminants. Furthermore, it can be easily produced in large quantities from various agricultural by-products, making it a sustainable and economically viable option . This work aims to investigate the production and characterization of natural based adsorbent materials, both in their natural form and as activated carbons, and their subsequent use for the purification of crude ethanolic biodiesel produced from waste cooking oil. The materials’ precursors were: almond shells, walnut shells, rice husks, olive pits, and powdered cork. The characterization tests conducted include moisture content determination, ash content, pH, bulk density, cellulose content, hemicellulose, and lignin content determination, particle size analysis, specific surface area measurement, determination of the zero point of charge, identification of basic and acidic groups, determination of chemical groups, and thermogravimetric analysis. Subsequently, adsorption performance tests will be carried out.
- Purification of biodiesel using a natural based adsorbent in a packed-bed columnPublication . Smolich, Camilla Groxko; Guimarães, Miriam D.; Fabian, João Vitor; Gomes, Maria Carolina Sérgi; Queiroz, Ana; Brito, Paulo; Ribeiro, António E.In Europe, the Renewable Energy Directiva stimulates the development of renewable energy sources to reduce greenhouse gas emissions by at least 55% by the year 2030 and to become aclimate-neutral continent by 2050 [1]. Biodiesel presents advantages over diesel fuel in terms of sulfur content, biodegradability, flash point, no aromatic content, higher cetane number and miscibility in petroleum diesel in any ratio [2]. The most used feedstock is high quality vegetable oil, but the use of waste cooking oil adds to the global reduction of residue, lower costs, and competes less for vegetable oils against the food industry [3]. This biofuel is obtained through transesterification, and glycerol is formed as a coproduct. lts presence can cause damage to motors so it must be removed until its final concentration is lower than 0.02wt%. The most used method is wet washing, but the downside is the great amount of water used and long periods of time are needed to separate biodiesel from its contaminants through decantation [4]. A promising altemative is dry washing method through adsorption using biomass activated carbon. For a more practica! application, packed columns are frequently used in large scale adsorption processes. lt is one of the most efficient configurations for treating great volumes of effluent and adsorption-desorption cycles [5]. For this study, crude biodiesel was produced through transesterification from a waste cooking oil sample, using ethanol and a basic catalyst (NaOH). Afterwards the biodiesel produced was characterized in terms of glycerol content. In parallel, activated carbon materials were obtained from olive pits by physical activation at 800°C. The adsorbent materials performance for glycerol removal from crude biodiesel is assessed using a continuous system based on a packed-bed column according to the following parameters: fluid rate, removal capacity, pressure drop and adsorbent recovery.