Physical and chemical properties of pulp waste for energy purposes
2018
Dabrowska, M., Warsaw Univ. of Life Sciences (Poland) | Kuittinen, S., University of Eastern Finland, Joensuu (Finland) | Pappinen, A., University of Eastern Finland, Joensuu (Finland) | Swietochowski, A., Warsaw Univ. of Life Sciences (Poland)
In pulp and paper industry biomass rich in energy is represented by pulping liquors, wood wastes, sludge and rejects. Many pulp and paper mills produce more than half of their energy needs from biomass fuels recovered from solid pulp and paper wastes. The end-products of conversion of these wastes are solid, liquid or gaseous fuels and moreover, in most cases, the valuable and ecological fertilizer. The proper method of biomass conversion depends on its structure and chemical composition, which includes hemicellulose, cellulose and lignin content. Pulp and paper industry generate a lot of quantities of valuable biomass as wastes in all stages of the process. Therefore, this paper reviews the current state of using waste from pulp and paper industry as a fuel for energy purposes. For investigation, the materials from four different types of pulp waste were used. Pulp waste I contained knots and barks and was a product of chemical and semi-chemical pulp processes and of mechanical pulp manufacture, pulp waste II contained final fibre waste sludge from kraft mill, pulp waste III contained fibre sludge from board mill and pulp waste IV contained final fibre waste sludge from board mill. The article contains a description of physical properties of pulp wastes such as: moisture content, density, gross and net calorific values. A chemical analysis includes determination of dry matter, element composition and contents of ash, glucan, xylan, mannan and lignin. It was found that residues from mechanical and chemical pulping varied in the origin and stage of production, had similar chemical composition, differed in a narrow range. Pulp waste materials are rich in sugars of above 52 %, reaching a value of approximately 71 %, depending on the sample taken at different stages of processing. Net calorific values for all tested raw materials were high in the range from 19.8 to 20.5 MJ•kgE-1 and should be considered as feedstock suitable to generate enough energy.
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