On the issue of achieving an optimal combination of production capacity, product quality and ecological safety of pulp and paper enterprises

The article discusses the practical aspects of changing the technological parameters of cooking sulfate coniferous unbleached cellulose in relation to the conditions of «Group «Ilim», a branch in Ust-Ilimsk, in the conditions of operation of a continuous cooking plant with exceeding the design capacity. The enlarged technological calculations have shown the need for reconstruction of the cooking and washing area in order to eliminate the negative consequences, which resulted in an increase in the productivity of the previously installed technological unit while trying to comply with acceptable environmental performance indicators of the enterprise. Achieving an optimal combination of production productivity, product quality and environmental friendliness of a pulp and paper enterprise is the goal of any production reconstruction and technology improvement. The operation of the continuous cooking unit in an overloaded mode leads to a reduction in the duration of the technological processes of impregnation of wood chips and subsequent sulfate cooking, causes problems with uniformity of movement of the wood chips in the zones of the digester and leads to a decrease in the efficiency of washing the resulting pulp. Since an increase in the capacity of the cooking unit leads to the production of rigid cellulose, from which residual lignin can be removed only when an additional bleaching stage using chlorine is included in the bleaching technological scheme, the content of organochlorine compounds in the wastewater of the cooking and washing department of the enterprise exceeds permissible environmental standards. The article proposes a variant of the reconstruction of a continuous cooking plant, which allows to increase the efficiency of the production of sulfate cellulose with the achievement of the required indicators of the discharge of pollutants into the environment. To eliminate the negative consequences of the operation of the cooking unit in conditions of a significant excess of its design the capacity, it is necessary to additionally install an impregnation column and increase the cooking zone by lowering extraction sieves into the zone of diffusion washing of the digester.

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