Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Cutting paper-making costs

The project identified opportunities for reducing energy consumption in pulp and paper making. Three manufacturing stages were investigated: wood chip treatment, pulp refining, and upgrading of waste paper. The results showed energy savings of up to 30 % in some process stages, and improvements in pulp brightness and the quality of products from waste paper.

In the first stage, wood chips were pre-treated with various chemical oxidizing agents prior to pulping. In the next stage, the fibres in the refinery system were treated mechanically to improve their homogeneity. Pulps from different origins, such as hardwoods or softwoods, were treated separately before blending to form pulp mixtures. The researchers found that different pulp compositions required different refining intensities and hence varying levels of energy inputs. These practical investigations were confirmed using a hydrodynamic model of the refining process. Finally, pulp from waste paper recycling was separated into different fractions according to fibre quality using a novel process of centrifugal cleaning. By separating the pulp fibres, good quality residues could be reclaimed and used in the production of higher quality papers.

Significant savings in energy demand were achieved at all of the stages investigated. Pre-treatment of wood chips achieved 5-10 % energy savings, whilst savings of up to 30 % were demonstrated in the pulp refining process. An added benefit was the improvements observed to the pulp brightness following pre-treatment. Further energy savings in the upgrading of waste paper also benefited from the improvements to the quality of the recovered pulp and therefore an increase in pulp value. These results show that not only can targeted efficiency actions reduce energy demand, they can also improve the value of the finished product.


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