Untitled

Funder

Organizational Unit

Publications

The Relationship of Higher Education Access with Final Marks in a Core Chemical Engineering Topic

Publication . Sena-Esteves, Maria Teresa; Morais, Cristina; Ribeiro, Margarida; Pereira, Isabel; Guedes, Anabela; Soares, Filomena; Leão, Celina P.

This present work cracks to understand the relationship between final marks in a topic with competences that are core of Chemical Engineering and students’ access grades to a Portuguese Higher Education Institution (HEI). The study is based on data gathered through a questionnaire concerning students’ perceptions about assessment and teaching-learning methodologies in four academic years (2016-2017 to 2019-2020). The student´s access grades were included in the questionnaire since 2018-19 academic year allowing to establish a relationship with the final marks obtained in a core Chemical Engineering Topic, Fluid Mechanics. From the analysis made, it can be said that students who obtained higher access grades to HEI may have also a higher Chemical Engineering curricular unit final mark, although the low linear relationship obtained (r =0.45) for the year 2019-20.

2020-10Conference object

Open access

Fat extraction from fleshings - optimization of operating conditions

Publication . Cunha, A.F.; Caetano, Nídia; Ramalho, Elisa; Crispim, Alfredo

Fat from fleshings is an excellent source of energy since it is composed of glycerides, fatty acids and glycerol. The present work aims to optimize the operating conditions of fat extraction from fleshings. Animal fat was obtained after thermal treatment of fleshings in a stainless steel batch reactor using different operating conditions (100T155 ºC; 1P5.5 bar, t= 2 h, r= 1000 rpm). The fat containing phases were extracted in a heated Soxhlet using n-hexane and ethanol to recover the fat from the solid residue. In addition, 6 M HCl acid was added to the remaining solid and heated to boiling conditions for 2 h to further extract fat that is encapsulated in the tissues of the fleshing. The best conditions of fat extraction were obtained at 155 ºC during 2 h and 1000 rpm that generated a pressure of 5.5 bar inside the batch reactor. It was also found that significantly higher amount of fat could be obtained at the operating conditions mentioned (50 wt. % on dry basis), sparring chemical treatments by using a 6 M HCl acid for additional fat extraction. Finally, this approach allowed to significantly reduce the environmental impact of solid waste, decreasing also the costs associated with disposal, while contributing to the circular economy of the tanning sector.

2020Conference object

Open access

Evaluation of potential tidal impoundment energy systems in Ria de Aveiro, Portugal

Publication . Rocha, João; Abreu, Tiago; Felgueiras, Carlos

The shelving of the seabed and funneling of the water by the estuaries is favorable for tidal impoundment technologies. In this work, the estimation of the tidal potential energy for Ria de Aveiro lagoon was achieved through the application of a model developed in the Delft3D software. This software can reproduce the hydrodynamics of this complex system and simulations were run to identify hot spots to retrieve gravitational potential energy. For the selected places, both power and annual energy were calculated. It was concluded that the tidal energy that can be extracted from Ria de Aveiro is considerable, justifying further studies to consider the accommodation of some type of tidal exploitation, in the foreseeable future.

2020Conference object

Open access

Enhancing extraction and purification of phycocyanin from Arthrospira sp. with lower energy consumption

Publication . Gorgich, Malihe; Passos, Marieta L.C.; Mata, Teresa M.; Martins, António A.; Saraiva, M. Lúcia M.F.S.; Caetano, Nídia

Phycocyanin is a light-blue water-soluble natural pigment with wide application in fields including pharmaceutical, cosmetic and food industry. Arthrospira platensis is considered a natural bio-factory for obtaining phycocyanin, and although suitable cultivation conditions can enhance the pigment content, the importance of extraction and purification should not be overlooked, because the chemicals used in those steps can affect the quality of phycocyanin. Further, changes in temperature, or approaches used to extract other protein types from biomass, have been reported to degrade phycocyanin, influencing its final quality, while also contributing to higher energy consumption in the extraction process. Hence, this work compares several approaches for phycocyanin extraction, and analyzed the effects of changes in operating conditions, such as exposure time, application of solvent buffer, and ultrasonication, on the extraction yield, the extracts purity, and the process energy use efficiency. Experimental results point to promising improvements in the extraction yield with high purity of phycocyanin (44.24 mg/g with purity ratio of 0.34), when suitable operating parameters were used (2 h exposure to potassium phosphate buffer with 20 min of ultrasonication).

2020Conference object

Open access

Economic analysis of microalgae biodiesel production in a small-scale facility

Publication . Branco-Vieira, M.; Mata, T.M.; Martins, A.A.; Freitas, M.A.V.; Caetano, Nídia

Industrial production and commercialization of biodiesel from microalgae have become a good alternative to conventional feedstock. Microalgae show high growth rate and carbon sequestration and can be easily cultivate in fresh and/or marine water, using non-arable soil. This study aims to analyze the technical and economic feasibility of biodiesel production from Phaeodactylum tricornutum, using an algae biomass production scaled-up scenario, considering local reality prices and available technologies. The model assumes 80,000 m3 of microalgae cultivation, in a set of bubble column photobioreactors installed on 15.247 ha of land, reaching a total of 1,811 tons of microalgae biomass and 171,705 L of biodiesel per year. The production cost estimated for microalgae biomass is 2.01 € kg−1 and for biodiesel is 0.33 € L−1. The ROI calculated for the project is 10% with a 10 years’ payback time and an EBITDA of 588,139 € year−1. Despite the project’s viability in the medium term, the cost of producing microalgae biodiesel remains high when compared to fossil fuels. Thus, unless greater technological maturity is achieved to make the process more economical, it will not be viable in the short term.

2020Journal article

Open access