A carregar...
Publicação
Avaliação do Ciclo de Vida do Processo de Dissolução/Precipitação no Tratamento de Resíduos Plásticos
| Nome: | Descrição: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 2.6 MB | Adobe PDF |
Autores
Orientador(es)
Resumo(s)
O crescente consumo de plásticos torna cada vez mais relevante o desenvolvimento de
estratégias sustentáveis para a reciclagem. O presente projeto teve como objetivo propor e
validar um método de separação de uma mistura de resíduos plásticos através do processo
de dissolução/precipitação. Para tal, a abordagem integrou a seleção de solventes verdes, a
avaliação dos riscos associados e a otimização das condições operacionais, visando
maximizar a eficiência do processo e o seu impacte ambiental.
Numa segunda fase, foi desenvolvida uma Avaliação do Ciclo de Vida (ACV) para
identificar e quantificar impactes ambientais do processo proposto, permitindo a comparação
com as soluções de fim de vida convencionais: a deposição em aterro e a incineração. A
unidade funcional considerada correspondeu ao tratamento de 100 kg de resíduos plásticos,
com vista à recuperação dos polímeros, numa abordagem porta-a-porta (gate-to-gate),
abrangendo as etapas de pré-tratamento e as operações unitárias associadas ao processo de
dissolução/precipitação. A avaliação foi realizada com recurso à metodologia de avaliação
de impacte Environmental Footprint (versão 3.1) e ao software SimaPro, recorrendo a dados
primários (obtidos experimentalmente e por via bibliográfica) e a dados secundários
provenientes da base de dados Ecoinvent (versão 3.11). Os resultados evidenciaram que as
emissões difusas de solvente e anti-solvente são os principais responsáveis pelos impactes
nas categorias de formação fotoquímica de ozono (47,8%) e toxicidade humana,
cancerígenos (5,5%). Por outro lado, o consumo de energia elétrica, associado sobretudo às
etapas de destilação, domina as restantes categorias de impacte mais relevantes: utilização
de recursos minerais (9,0%) e fósseis (8,2%), toxicidade humana, não cancerígenos (5,2%)
e alterações climáticas (4,2%).
Apesar do processo em estudo apresentar impactes ambientais superiores à incineração e
deposição em aterro, este trabalho contribuiu para disponibilizar uma possível metodologia
para a seleção de solventes e separação de uma mistura de resíduos plásticos.
Adicionalmente, apresenta um modelo de escalonamento do nível laboratorial para o
industrial, fornecendo um inventário detalhado e resultados específicos que servem de base
para otimização e implementação desta tecnologia no âmbito da economia circular.
The growing consumption of plastics makes the development of sustainable recycling strategies increasingly important. The aim of this project was to propose and validate a method for separating a mixture of plastic waste using the dissolution/precipitation process. To this end, the approach incorporated the selection of green solvents, the assessment of associated risks and the optimisation of operating conditions, with a view to maximising the efficiency of the process and minimising its environmental impact. In a second phase, a Life Cycle Assessment (LCA) was carried out to identify and quantify the environmental impacts of the proposed process, enabling a comparison with conventional end-of-life solutions: landfill disposal and incineration. The functional unit considered corresponded to the treatment of 100 kg of plastic waste, with a view to recovering the polymers, using a gate-to-gate approach, covering the pre-treatment stages and the unit operations associated with the dissolution/precipitation process. The assessment was carried out using the Environmental Footprint methodology (version 3.1) and SimaPro software, drawing on primary data (obtained experimentally and from the literature) and secondary data from the Ecoinvent database (version 3.11). The results showed that diffuse emissions of solvent and antisolvent are the main contributors to impacts in the categories of photochemical ozone formation (47,8%) and human toxicity, carcinogens (5,5%). On the other hand, electricity consumption, associated mainly with the distillation stages, dominates the other most relevant impact categories: use of mineral resources (9,0%) and fossil resources (8,2%), human toxicity, non-carcinogens (5,2%) and climate change (4,2%). Although the process under study has a greater environmental impact than incineration and landfill disposal, this study has helped to establish a potential methodology for selecting solvents and separating a mixture of plastic waste. Furthermore, it presents a model for scaling up from the laboratory to the industrial level, providing a detailed inventory and specific results that serve as a basis for the optimisation and implementation of this technology within the circular economy.
The growing consumption of plastics makes the development of sustainable recycling strategies increasingly important. The aim of this project was to propose and validate a method for separating a mixture of plastic waste using the dissolution/precipitation process. To this end, the approach incorporated the selection of green solvents, the assessment of associated risks and the optimisation of operating conditions, with a view to maximising the efficiency of the process and minimising its environmental impact. In a second phase, a Life Cycle Assessment (LCA) was carried out to identify and quantify the environmental impacts of the proposed process, enabling a comparison with conventional end-of-life solutions: landfill disposal and incineration. The functional unit considered corresponded to the treatment of 100 kg of plastic waste, with a view to recovering the polymers, using a gate-to-gate approach, covering the pre-treatment stages and the unit operations associated with the dissolution/precipitation process. The assessment was carried out using the Environmental Footprint methodology (version 3.1) and SimaPro software, drawing on primary data (obtained experimentally and from the literature) and secondary data from the Ecoinvent database (version 3.11). The results showed that diffuse emissions of solvent and antisolvent are the main contributors to impacts in the categories of photochemical ozone formation (47,8%) and human toxicity, carcinogens (5,5%). On the other hand, electricity consumption, associated mainly with the distillation stages, dominates the other most relevant impact categories: use of mineral resources (9,0%) and fossil resources (8,2%), human toxicity, non-carcinogens (5,2%) and climate change (4,2%). Although the process under study has a greater environmental impact than incineration and landfill disposal, this study has helped to establish a potential methodology for selecting solvents and separating a mixture of plastic waste. Furthermore, it presents a model for scaling up from the laboratory to the industrial level, providing a detailed inventory and specific results that serve as a basis for the optimisation and implementation of this technology within the circular economy.
Descrição
Palavras-chave
Plásticos Sustentabilidade Dissolução/Precipitação Solventes verdes Avaliação do ciclo de vida Economia circular