DOSING ACCURACY IN THE PAPER INDUSTRY | QDOS PERISTALTIC PUMPS
Above: A Qdos 120 pump used for dosing lime slurry
global leader in moulded fibre technology for food and drink packaging. Full- scale industrial trials took place at the company’s central research facility in the Netherlands. The dry stock material used for these trials was a mixture of recycled paper fibres with grass added. An important aspect of pulp production is to ensure neutral pH of the pulp by the addition of lime. Adding lime contributes to lower bacterial growth and decreases the presence of fatty acids in the pulp. This Lime dosing accuracy has a significant impact on process performance and end product quality
Introduction Paper making uses large volumes of water, 90% of which is used for cooling and 10% as process water. Fibre is mixed with water at the stock preparation stage of the process in order to create pulp. This step is followed by forming and dewatering stages, where vacuum is applied to drain the water. Any remaining water in the product is evaporated in the drying section, most often by gas-heated ovens or steam-heated drying cylinders. The paper drying section consumes most of the energy in the manufacturing process, and contributes to 68% of the total greenhouse gas emissions for the sector. However, increasing performance in the dewatering stage delivers the potential for less water to be heated and evaporated in the drying section. To enhance dewatering, additives are used to increase drainage of the paper fibres. The calcium carbonate content
of the raw material also has a significant influence on dewatering, an area which seems underestimated by most process technologists. The problem The reality is that the forestry industry contributes 5% to global greenhouse gas emissions and uses 2% of the world’s energy industry-wide. As a result pulp and paper mills face strict and tightening regulations towards environmental issues. Apart from ambitious water reuse targets emissions need to be reduced significantly, which challenges the future profitability of many paper mills. The solution The deployment of accurate chemical dosing technologies at paper mills can deliver a significant reduction in energy usage and greenhouse gas emissions. To evaluate the feasibility of this thinking, comprehensive trials took place at Huhtamaki OY, a Finnish multinational and
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