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Melhoria do Processo e da Qualidade de Fibra Acrílica Pigmentada e Atualização de P&ID's
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A produção de fibras acrílicas pigmentadas enfrenta desafios importantes, nomeadamente a estabilização da cor, a fiabilidade dos equipamentos, as exigências do mercado no desempenho têxtil e a aplicação de acabamento. O tempo necessário para a transição de cor é diretamente influenciado pela eficiência da limpeza do circuito de injeção de dispersões de pigmentos. Com a instalação de um novo circuito, reduziu-se o tempo de lavagem em 52% para a máquina A e 42% para a máquina B. Com a análise das eficiências das bombas de engrenagens e das medições de caudal dos instrumentos de medida, concluiu-se que as bombas A2 e B2 tinham eficiências abaixo de 75%,
procedendo-se à sua substituição e que os caudalímetros FI-B1, FI-C1 e FI-A2, registavam maiores desvios. Os erros na medição dos caudalímetros estavam relacionados com um erro na montagem do equipamento. Após a calibração da reta de densidades dos caudalímetros, a diferença das densidades medidas entre os caudalímetros de gamas diferentes passou de 0,16 para 0,02. Concluiu-se que a densidade média das dispersões de pigmentos é de 0,977 ± 0,019 g/cm3. Durante a produção, parâmetros como o frisado do filamento e a cardação da mecha condicionam diretamente a qualidade da fibra. As propriedades analisadas da fibra de cor verde-botella, de modo geral, aumentaram os seus valores. Em relação às restantes cores, aumentou-se 8% no número de frisado, 18% no grau de frisado, 45% na tenacidade e 39% na
coesão. Concluiu-se que o pH na cuba de acabamento estava a influenciar a aplicação de acabamento na fibra. A variação do pH foi corrigida com bicarbonato de sódio, mantendo-o em 8,23 ± 0,25 %m/m. O valor de extratado de acabamento na fibra passou de um valor médio 0,67 ± 0,7 %m/m, para o valor médio de 0,72 ± 0,04 %m/m. Foram atualizados 4 diagramas de tubagens e instrumentação (P&ID's) e elaboraram-se 5 diagramas novos.
The production of pigmented acrylic fibres faces significant challenges, namely colour stabilisation, equipment reliability, market demands on textile performance, and finishing ap plication. The time required for colour transition is directly influenced by the efficiency of cleaning the pigment dispersion injection circuit. With the installation of a new circuit, washing time was reduced by 52% for machine A and 42% for machine B. By analysing the efficiency of the gear pumps and the flow measurements from the measuring instruments, it was concluded that pumps A2 and B2 had efficiencies below 75%, leading to their replacement. Additionally, flow meters FI-B1, FI-C1, and FI-A2 showed the highest deviations. Errors in flow meter readings were linked to an installation error in the equipment. After calibrating the density curve of the flow meters, the difference in measured densi ties between different flow meter ranges decreased from 0.16 to 0.02. It was concluded that the average density of the pigment dispersions is 0.977 ± 0.019 g/cm3. During production, parameters such as filament crimping and sliver carding directly impact fibre quality. The analysed properties of the bottle-green fibre generally showed improved values. Compared to other colours, crimp number increased by 8%, crimp degree by 18%, tenacity by 45%, and cohesion by 39%. It was concluded that the pH in the finishing bath was affecting the application of the finish on the fibre. The pH variation was corrected using sodium bicarbonate, stabilising it at 8.23 ± 0.25 %w/w. The value of finishing extract on the fibre increased from an average of 0.67 ± 0.07 %w/w to a new average of 0.72 ± 0.04 %w/w. Additionally, four Piping and Instrumentation Diagrams (P&ID) were updated, and five new ones were created.
The production of pigmented acrylic fibres faces significant challenges, namely colour stabilisation, equipment reliability, market demands on textile performance, and finishing ap plication. The time required for colour transition is directly influenced by the efficiency of cleaning the pigment dispersion injection circuit. With the installation of a new circuit, washing time was reduced by 52% for machine A and 42% for machine B. By analysing the efficiency of the gear pumps and the flow measurements from the measuring instruments, it was concluded that pumps A2 and B2 had efficiencies below 75%, leading to their replacement. Additionally, flow meters FI-B1, FI-C1, and FI-A2 showed the highest deviations. Errors in flow meter readings were linked to an installation error in the equipment. After calibrating the density curve of the flow meters, the difference in measured densi ties between different flow meter ranges decreased from 0.16 to 0.02. It was concluded that the average density of the pigment dispersions is 0.977 ± 0.019 g/cm3. During production, parameters such as filament crimping and sliver carding directly impact fibre quality. The analysed properties of the bottle-green fibre generally showed improved values. Compared to other colours, crimp number increased by 8%, crimp degree by 18%, tenacity by 45%, and cohesion by 39%. It was concluded that the pH in the finishing bath was affecting the application of the finish on the fibre. The pH variation was corrected using sodium bicarbonate, stabilising it at 8.23 ± 0.25 %w/w. The value of finishing extract on the fibre increased from an average of 0.67 ± 0.07 %w/w to a new average of 0.72 ± 0.04 %w/w. Additionally, four Piping and Instrumentation Diagrams (P&ID) were updated, and five new ones were created.
Descrição
Palavras-chave
Fibras acrílicas pigmentadas Bombas de engrenagem Caudalímetro Coesão Acabamento