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Abstract(s)
A presente dissertação, realizada em ambiente industrial na Amorim Cork, S.A., teve como objetivos: (i) obter lavações homogéneas e um processo uniformizado e robusto, (ii) reduzir o consumo de reagentes químicos, (iii) reduzir o valor residual de peróxido de hidrogénio presente nas rolhas aglomeradas de cortiça após o processo de lavação e (iv) melhorar a qualidade visual das rolhas aglomeradas de cortiça após o processo de lavação. Para tal foram realizados ensaios laboratoriais que consistiram no estudo do impacto de diferentes proporções de reagentes (NaOH e H2O2) no pH da solução resultante, tendo em vista a redução dos reagentes responsáveis pela formação do agente de branqueamento. Nestes ensaios foram estudadas quatro proporções diferentes, tendo como ponto de partida as quantidades utilizadas na lavação corrente na unidade industrial. De seguida realizaram-se ensaios industriais, partindo dos resultados obtidos nos ensaios laboratoriais, tendo sido feita a reformulação dos passos do programa de lavação e a otimização das condições de operação. Foram realizados doze ensaios industriais, dos quais três tiveram como objetivo a redução dos reagentes, cinco a otimização das condições de temperatura ao longo do programa e os restantes quatro a redução do valor residual de peróxido de hidrogénio. Por fim fez-se a validação do programa otimizado através da realização de 26 ensaios industriais nas condições otimizadas. Os valores de brancura ISO dos ensaios de validação foram comparados estatisticamente com os da lavação corrente na unidade industrial. Os resultados obtidos mostram que a lavação resultante desta dissertação apresentou maior homogeneidade entre lavações quando comparada com a lavação atual, um valor médio residual de peróxido de hidrogénio aprovado, em média, ao fim de 15,5 horas após a lavação e permite uma diminuição do custo dos reagentes de lavação de cerca de 54,7%.
The objectives of this dissertation, carried out in an industrial environment at Amorim Cork S.A., were to (i) obtain homogenous washing and a uniform and robust process, (ii) reduce the consumption of chemical reagents, (iii) reduce the residual value of hydrogen peroxide present in agglomerated cork stoppers after the washing process and (iv) improve the visual quality of the agglomerated cork stoppers after the washing process. For this purpose, laboratory tests were carried out which consisted of studying the impact of different proportions of reagents (NaOH and H2O2) on the final pH of the solution, aiming the reduction of the reagents responsible for the formation of the whitening agent. In these tests four different reagent mixtures were studied, using as a starting point the amounts used in the current washing process in the industrial unit. Next, industrial trials were performed, in which the results obtained in the laboratory trials were applied, the washing program steps were reformulated, and the operating conditions were optimized. A total of twelve industrial tests were performed, three of which aimed at reducing the reagents, five aimed at optimizing the temperature conditions throughout the program, and the remaining four aimed at reducing the residual value of hydrogen peroxide. Finally, the validation of the optimized program was carried out through 26 industrial trials under optimized conditions. The ISO whiteness values of the validation tests were statistically compared with those of the current washing in the industrial unit. The results obtained show that the washing conditions resulting from this dissertation showed greater homogeneity between washings when compared to the current washing, an average residual value of hydrogen peroxide approved, on average, after 15.5 hours after washing and allows a decrease in cost of wash reagents of about 54.7%.
The objectives of this dissertation, carried out in an industrial environment at Amorim Cork S.A., were to (i) obtain homogenous washing and a uniform and robust process, (ii) reduce the consumption of chemical reagents, (iii) reduce the residual value of hydrogen peroxide present in agglomerated cork stoppers after the washing process and (iv) improve the visual quality of the agglomerated cork stoppers after the washing process. For this purpose, laboratory tests were carried out which consisted of studying the impact of different proportions of reagents (NaOH and H2O2) on the final pH of the solution, aiming the reduction of the reagents responsible for the formation of the whitening agent. In these tests four different reagent mixtures were studied, using as a starting point the amounts used in the current washing process in the industrial unit. Next, industrial trials were performed, in which the results obtained in the laboratory trials were applied, the washing program steps were reformulated, and the operating conditions were optimized. A total of twelve industrial tests were performed, three of which aimed at reducing the reagents, five aimed at optimizing the temperature conditions throughout the program, and the remaining four aimed at reducing the residual value of hydrogen peroxide. Finally, the validation of the optimized program was carried out through 26 industrial trials under optimized conditions. The ISO whiteness values of the validation tests were statistically compared with those of the current washing in the industrial unit. The results obtained show that the washing conditions resulting from this dissertation showed greater homogeneity between washings when compared to the current washing, an average residual value of hydrogen peroxide approved, on average, after 15.5 hours after washing and allows a decrease in cost of wash reagents of about 54.7%.
Description
Keywords
Branqueamento Agente de branqueamento Brancura ISO Valor residual de peróxido de hidrogénio Bleaching Bleaching agent ISO whiteness Hydrogen peroxide residual value