Avaliação da viabilidade da implementação industrial do ozônio para o branqueamento de papel e celulose

Abstract

Ozone is a chemical compound known for its high oxidizing power. It is an environmentally friendly alternative for the substitution of chlorinated compounds used in the bleaching of paper and cellulose, which generate highly toxic and recalcitrant byproducts and may even be carcinogenic. This study intends to verify the viability of its implementation as a bleaching agent, evaluating technical, socioenvironmental and economic aspects. Online questionnaires were prepared to be sent to the paper and pulp industries to collect these data. Responses from three companies were obtained, one of which uses ozone in its bleaching sequence and all of them have a large and prominent feature in the pulp and paper production market, both nationally and globally. Thus, the collected parameters were analyzed comparatively and, therefore, discussed based on the literature. The use of ozone, despite resulting in inferior mechanical quality, obtains better optical quality results of the pulp. In addition, as their contact with cellulosic pulp must be minimal, total processing time is reduced, which allows the industry a greater productive capacity. With regard to environmental aspects, the use of ozone drastically reduces the volume of effluents generated, as well as presenting the minimum possible toxicity and, consequently, less harm to society, especially if no chlorine compounds are used in the bleaching sequence. In the case of economic areas, the use of ozone demands lower consumption of electricity, weighted by the productive capacity, contrary to the common sense that consumes more energy due to its generation system, which is constantly adapting and improving. Besides that, it greatly reduces water consumption and shows a good saving of chemical reagents, in particular the reduction of the applied dose of chlorine dioxide (if present in the bleaching sequence) and the consumption of oxygen, the only by-product of its generation, which can be reused because of its great use in the pulp and paper industry. In this way, it is concluded that the use of ozone as a bleaching agent is feasible and of great interest to society, and, in any case, a prior evaluation by the industry is required to carry out its implementation.