Processo hibrido de polpação etanol-soda de madeira de eucalipto, com baixo teor alcoolico

AUTOR(ES)
DATA DE PUBLICAÇÃO

1989

RESUMO

The aim of this work was the development of a chemical wood pulping process free of sulfur compounds that could provide a quality cellulose without causing a severe environmental impact. All pulping variables were studied including bleaching (C.E.H1.H2), and physical properties of the crude and bleached pulps. The recovering of ethanol and soda was also verified. Presently, in Brazil, kraft is the most used process. Notwithstanding the excellent quality of the pulp, the sulfur compounds produced, as mercaptans and H2S, are extremely aggressive to the ecology. The results of this work show that it is possible to obtain cellulosic pulp similar to that obtained with the kraft method by ethanol-soda pulping. a considerably less polluting process. The new method was adjusted to the conditions of an already installed kraft plant. As reference the plant of RIPASA SA Celulose e Papel in Limeira. São Paulo, was used. The pulping conditions suggested can be summarized as follows: ethanol concentration, about 20% v/v; soda concentration, ca. 20% (as Na2O), on wood; pulping temperature, 160°C temperature rise time, 60 minutes; pulping time at 160°C, 65 min; liquor to wood ratio, 4.26/1 l/kg. A better yield with lower rejects contents was obtained for the ethanol-soda pulp in relation to the soda and kraft methods. The recovering of the ethanol reached 93%, while for the alkali 12% of the initial quantity was recovered. The ethanol-soda pulps showed a better bulk, brightness and opacity than the kraft ones. Physical properties showed intermediate behaviour between soda e kraft pulps, with some tendencies to the latter.

ASSUNTO(S)

eucalipto polpa de madeira polpação alcalina por soda

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