Impacto da dosagem de ácido no primeiro estágio de dióxido no branqueamento de polpa celulósica de pinus

Abstract

The growing expansion of national pulp production has brought Brazil great worldwide relevance in the export of the commodity. In the context of bleaching with chlorine dioxide, the knowledge of the parameters that influence the acid load and its impacts on the process are presented broadly and sometimes distributed within each factory panel operator. This work aimed to study the previous and subsequent variables to the first stage acid dosage of Pinus pulp bleaching, in a factory in the state of Paraná. The behavior of the measurements was collected using the software Wedge within a stipulated period of six months. Graphs were generated from the history of trends in conductivity, COD, alkaline loss and pH of the depuration pulp filtrate, acid load, dioxide load and pH of the bleaching, delignification alkaline load, soda dosage in the second stage of bleaching, pH of the effluents, the torque of the bleaching washer and temperature of the washing filtrate. The trends were visually combined according to their relevance to the analysis and investigated variations. A significant relation between the dosage of acid with the depuration conductivity and inlet pH of the first dioxide reactor was observed, revealing the importance of factors such as efficient washing of the depuration, low pH variation in the reactor feed, and stability of the production. The influence of acid load excess on the formation of scale and expenses with subsequent chemicals to correct pH were also presented. Finally, summary boards were produced bringing together the main observations and relation between the variables analyzed, thus contributing to the expansion and leveling of knowledge of the industry operation.