Search

The paper industry is heavily using energy during all the phases of the manufacturing process. This is especially the case in Nordic mills where pressure ground wood is the source of fiber. The purpose of this case study is to show how energy consumption behaves on a monthly basis in a Finnish paper mill that has several paper machine lines. The research examines different categories of energy usage, as well as the overall costs. The results show that the monthly energy usage varies significantly. The electricity consumption of the case mill is rather steady, but there is significant monthly variation in steam and natural gas consumption. Moreover, steam and electricity unit costs increased significantly when coming to the end of the research period. The longitudinal case data shows that it is difficult to enhance energy consumption per produced unit at the paper mill. One reason for this is the bleak demand outlook for the end products, which often result in downsizing and closing operations inside the integrated unit. [ABSTRACT FROM AUTHOR]

Abstract: From the utilization point of view, it is notable that the total element concentrations in the precipitated calcium carbonate (PCC) waste were significantly lower than the maximal allowable heavy metal concentrations for fertilizers used in agriculture and in forestry, set on the basis of the EU and Finnish legislation. The easily soluble Ca concentration of 168.5gkg−1 (d.w.) in PCC waste was 105 times higher than the typical value of 1.6gkg−1 (d.w.) in the coarse mineral soil in Finland indicates that the PCC waste is a potential agent for soil remediation and for improving soil fertility if it is used as fertilizer. According to a five-stage sequential extraction procedure, the highest concentrations of most of the elements occurred either in HF+HNO3 +HCl or H2O2 +CH3COONH4 fraction. This means that the major part of the elements retained in the PCC waste are not easy to extract (leach) under conditions normally found in nature. This is beneficial since, if inorganic materials and by-products are utilized in earth construction, the content of harmful compounds must be low and the harmful components must be tightly bound to the matrix. [Copyright &y& Elsevier]