Avaliação do efeito das variáveis de processo e das propriedades mecânicas no branqueamento de polpa celulósica com peróxido pressurizado

• Autor(a) principal: Marcondes, Camila Juliane [UNESP]
• Data de Publicação: 2015
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/155599; http://www.athena.biblioteca.unesp.br/exlibris/bd/capelo/2017-07-11/000886239.pdf
• topic: Celulose; Branqueamento; Madeira - Quimica; Cellulose

The bleached pulp market has been working to promote whiteness levels with 92% ISO values obedience, however, environmental standards and seeking less aggressive processes. Then, the additional chlorine dioxide that would be necessary to lift brightness values has been replaced by hydrogen peroxide. The present study aimed to evaluate the influence of the variation of hydrogen peroxide load, pressure and temperature in the bleaching sequence D0(E+P)D1(PO). It was used industrial kraft pulp, from hybrid of Eucalyptus grandis x urophila, pre-delignified with oxygen, whose features were initial brightness of 61.8 % ISO, viscosity of 36,9 cp and 8.9 of Kappa number. The last stage (PO) was done varying the hydrogen peroxide load (3 kg/t and 6 kg/t), temperature (95 °C and 105 °C) and pressure (0 atm and 5 atm).To study the effect of such variations in the pulp were run physical, mechanical, chemical and optical analyzes determined according to the procedures described by TAPPI standard. In general, increased hydrogen peroxide load of 3 kg/t to 6 kg/t led to a small increase in values of brightness parameter and decreasing the viscosity of the pulp studied. The increase of 10 °C in the temperature of the system had a positive effect on the brightness parameter, for the analysis of viscosity the values showed a reduction. For varying the oxygen pressure there was an increase in brightness and reduction of viscosity. The study of brightness reversion showed low values as expected due to the high stability of whiteness of hydrogen peroxide. The study of mechanical properties showed that the TI values showed a decline to the variation of pressure and temperature. Contrary to what happened to the variation of hydrogen peroxide where the values were increased when the level of refining did not stand out to the various system parameters (pressure, load and temperature). IR suffered decrease in oxygen pressure, temperature peroxide and...