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- Design of Pyrolysis System to Convert Waste Plastic to FuelsPublication . Oliveira, Nelson S.; Pardo, Michael; Capela, Carlos; Gaspar, Marcelo; Vasco, Joel; Heleno, LizeteThe conventional recycling technology to process waste plastic, mechanical recycling, is not suitable to recycle waste thermoplastic with high content of contamination. Pyrolysis is a promising technology since it can convert into valuable products, such as fuels and monomers. This study focused on the design of the pyrolysis equipment for waste plastic based on polyolefins. The feeder of waste plastic is a worm screw conveyor that will be in a pre-heating system. The batch reactor has support for catalyzer and can operate between 300 up to 600 ºC with attached induction system for heating. The output flows into condenser in series to separate two liquid phases and gases, depending on its boiling point. The 3D model was done with SolidWorks, control system modelled in CADe SIMU and particle simulation with FloXpress.
- Feasibility Study of the PET Fines Incorporation into Recycling ProcessesPublication . Nascimento, Bruna Guilherme do; Bozzola, Fernando; Vasco, Joel C.; Parnigoni, Milena; Capela, Carlos; Heleno, Lizete; Gaspar, Marcelo; Oliveira, Nelson S.Circular economy principles focus on the need to preserve natural resources and foster the use of environmentally sustainable practices. Concerning the use of plastics in a circular economy, increasingly demanding solutions have to be developed towards the zero-waste goal sought after by researchers and society alike. Particular attention has been put into the recycling of PET, mainly due to its wide spectrum of use and, consequently, to large volumes of related waste. The PET mechanical recycling process requires these waste materials to be shredded into PET flakes. Following such a procedure, these flakes are pelletized to be used again as feedstock. Considering the main stages of the mechanical recycling processes, which include plastic screening, shredding and washing, significant amounts of end waste materials are generated. This end-waste integrates small scale particles that are designated by plastic fines. Concerning the PET recycling process, the PET fines resulting from its mechanical recycling are not currently valued due to several technical issues, such as their high contamination level and the complexity of sorting them from other small-size particles. Current research focuses on the feasibility of incorporating these PET fines into the film/injection extruders, avoiding this way the need for an intermediate pelletization stage. To allow for such direct incorporation of PET fines into recycling processes, different decontamination and sorting solutions were implemented and tested. The current study is based on analyzing the mechanical properties of PET fines, using laboratory tests such as FTIR, DSC, MFI, moisture content, tensile tests and bending tests. Preliminary results allow foreseeing the successful direct incorporation of PET fines into PET recycling.
- Ink Removal on Plastic Films Printed by FlexographyPublication . Bozzola, Fernando; Nascimento, Bruna Guilherme do; Vasco, Joel C.; Silva, Nelson; Lagoa, Fernando; Capela, Carlos; Heleno, Lizete; Gaspar, Marcelo; Oliveira, Nelson S.Plastics are key engineering materials for our society and economy, mainly due to their multifunctionality and ease of processing. Nonetheless, their main drawback is related to the fact that when these cannot be reprocessed, they do generate waste, which leads to several environmental impacts. Therefore, considering plastics’ circularity, minimizing their waste, and the resulting impacts, stresses the need for these to be recyclable. One of the main challenges that concern their recyclability is the deinking of plastic films when printed by flexography. The current technology uses non-bio-based surfactants and non-renewable surfactants, which are harmful to the environment. Therefore, the main objective of current research is to develop an environmentally sustainable process for ink removal on printed post-industrial flexible plastic films using bio-based surfactants. This process focuses on obtaining a deinked plastic that may be reprinted, avoiding this way for inappropriate disposal or reprocessing problems. The value increase of upcycling such post-industrial waste makes it possible to match the quality of the virgin plastic, which is key to carrying out an effective cost analysis of recycled plastic when compared to the new plastic films. Dedicated laboratory deinking procedures were undertaken with transparent polyethylene films printed by flexography with different conditions. Preliminary results show the dedicated experimental ink removal procedure using bio-based surfactants to be effective and environmentally sustainable.
- Sustainability Assessment of Building Rehabilitation Solutions: The Mid 70s Portuguese BuildingPublication . Reis, Alexandre; Heleno, Lizete; Monteiro, Silvia; Oliveira, Nelson S.The Energy Performance of Buildings Directive (EPBD) establishes improvements to buildings’ comfort conditions and energy performance, bringing them closer to buildings with almost zero energy needs, namely the Nearly Zero Energy Building (NZEBs). The assessment tools for sustainable construction, more recognized internationally, are LEED and BREEAM, and in Portugal is the LiderA. The application of those tools promotes energy efficiency and decarbonization of buildings, as referred to in the Portuguese Long-Term Strategy for Building Renovation (LTRS-PT) until 2050. In this case, a house representative of the construction of the period between 1971 and 1980 in Portugal was chosen to evaluate environmental sustainability using LiderA. In the current conditions, the LiderA rating class of the house was D. To improve the performance of the building were identified balanced rehabilitation solutions without excessive automation. The presented solutions should avoid transforming the house into a complicated device with operational difficulties or specialized operation. In this way, the proposed interventions in the building and systems are based on renewable sources, prioritizing energy and water efficiency. Furthermore, as a contribution to the health and well-being of the occupants, we considered measures related to indoor air quality (IAQ) and noise minimization. In addition, the encouragement of native species has contributed to ecological enhancement. With that proposals, the house rating class using LiderA improved from class D to class A+.
- Sustainability Performance of Buildings in the Project Stage—Residence StudentsPublication . Heleno, Lizete; Baptista, Pedro; Marta Gregório; Oliveira, Nelson S.; Monteiro, SilviaIn recent years, the concept of sustainable construction has been promoted by demand and by regulations. Several methodologies to assess the sustainability of the construction have been spread across the world, by several countries for almost all continents. This study focuses on the most used construction sustainability assessment methodologies, which were compared with the Portuguese methodology, LiderA. It was found that the LiderA is the sustainability system with the greatest number of relevant criteria, considering the three dimensions of sustainability, environment, economy and social. Considering the 5 phases of the construction life cycle, the importance to apply these methodologies in construction is crucial in the early phases. It can help to draft the sustainability classification of the building. To apply the LiderA was used a residence of students, a building composed of apartments, in the phase of planning. All of the 40 criteria from the LiderA were classified from F to A++, according to the project of the residence of students. The final classification, as it was projected, was A, meaning that the building has an environmental performance 50% higher than usual practice. The category of criteria with the highest contribution was the category of quality of service and resilience, with a percentage of achievement greater than 50%. The local dynamics and the resources category were the categories with the lowest contribution, and they have the potential to be reevaluated by the building promoter, since it has the potential to improve the sustainability classification of the residence of students.
- Recycling of PET fines waste by density separation: a way to circularity of plasticPublication . Heleno, M. L.; Oliveira, N. S.; Gaspar, M.; Silveira, A.; Vasco, J.Plastic is one of the most used materials due to its specific characteristics such as high flexibility and impact resistance, low cost, formability, light weight and recyclability. In this set, polyethylene terephthalate (PET) based materials are among of the most used plastics on the packaging market worldwide. The European strategy for plastics aims to modify the processes of design, production, use and recycling of plastics. It becomes crucial to study solutions to enhance the circularity of plastics in recycling processes. Therefore, it is mandatory to evaluate the potential separation of PET fines resulting from the recycling process of PET bottles (post-consumer waste), which are still contaminated by other polymers and other materials. The recovery of PET fines was successfully achieved with a multistage density plastics separation process, consisting on the use of solutions of different densities and ensuring the adequate wettability of the residues in the solutions. The addition of this multistage separation process by plastics density, improves PET fines recovery, by achieving 91.7% of pure PET fines from plastic material waste.
- Sustainability study of limestone quarry waste into value-added products: PCC and GCCPublication . Monteiro, S. M. C. S.; Jorge, Muanassa; Heleno, M. L.; Oliveira, N. S.; Alves, M. L.; Veiga, A.; Silva, A.Calcium carbonate can be obtained naturally from limestone, chalk, marble, and other sedimentary rock forms. Ground calcium carbonate (GCC) and precipitated calcium carbonate (PCC) are two materials that can be produced from natural calcium carbonate. The future of GCC and PCC is promising since they are linked to industries with high demand, such as packaging, building & construction, transportation, and industrial applications, with an expected compound annual growth rate higher than 4% until 2027. This research focuses on the production of GCC and PCC through a comparative analysis that identifies the macro conditions that become advantageous to produce and commercialising PCC in a quarry context. This allows a valorisation of the limestone waste resulting from the extraction operations, converting it into by-products of the process. Not all existing limestone quarries in the Serra de Aire e Candeeiros region are suitable sources of raw material to produce PCC. The five extraction poles were identified with the potential for extracting suitable raw materials, associated with several companies dedicated to the extraction operation in these quarries.