Browsing by Author "Larsson, Sylvia H."

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    Cyclone processing of green liquor dregs (GLD) with results measured and interpreted by ICP-OES and NIR spectroscopy
    (2016-11-15) Mäkelä, Mikko; Geladi, Paul; Grimm, Alejandro; Dahl, Olli; Pietiläinen, Antti; Larsson, Sylvia H.; Swedish University of Agricultural Sciences; Department of Forest Products Technology; Department of Bioproducts and Biosystems
    An experimental design in cyclone drying parameters for green liquor sludge led to an efficient drying of the material and an interpretation of optimal cyclone parameters. The obtained dried materials were analyzed by ICP-OES and NIR spectroscopy. The inorganic analysis showed that a partial separation of toxic chemicals is possible and the NIR results could be used as an extra way of interpreting the results of the experimental design. The conclusion is that besides drying, also a change in chemical composition occurs as an effect of cyclone treatment. The NIR method is fast and requires little sample preparation while the ICP-OES method gives more direct inorganic results but is more demanding in time for sample handling and measurement.
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    Process water properties from hydrothermal carbonization of chemical sludge from a pulp and board mill
    (ELSEVIER SCI LTD, 2018-09) Mäkelä, Mikko; Forsberg, Julia; Söderberg, Christer; Larsson, Sylvia H.; Dahl, Olli; Department of Bioproducts and Biosystems; Clean Technologies; RISE Processum AB; Iggesund Paperboard AB; Swedish University of Agricultural Sciences
    Hydrothermal carbonization (HTC) can be used to break down sludge structure and generate carbonaceous hydrochar suitable for solid fuel or value-added material applications. The separation of char and the reaction medium however generates a filtrate, which needs to treated before potential discharge. Thus, this work determined filtrate properties based on HTC temperature and sludge moisture content and estimated the discharge emissions and the potential increase in analyte loads to an industrial wastewater treatment plant based on derived regression models. Direct discharge of HTC filtrate would significantly increase effluent emissions at the mill, indicating the filtrate treatment is crucial for the future implementation of HTC at pulp and paper mills. Recycling the HTC filtrate to the wastewater plant would lead to only a nominal increase in effluent flow, but would increase the suspended solids, BOD, COD and total nitrogen loads by 0.1–0.8%, 3.8–5.3%, 2.7–3.1% and 42–67%, respectively, depending on HTC temperature.