Low Energy CTMP in Paperboard

The aim with this project is to develop and demonstrate technique, which will make it favourable to use a low energy CTMP in manufacturing of multiply paperboard.

The total energy consumption in refining of such CTMP should be lower than 600 kWh/ton. The CTMP should principally be added to a middle ply in the paperboard and create opportunities for reduction of the grammage at production of a final product quality with certain bending stiffness.

Project approach

It can be stated that new basic technique for manufacturing of high quality CTMP from both softwoods and hardwoods at a very low electric energy consumption for use in paperboard qualities is now available!

The energy consumption in manufacturing of these pulps are substantially lower than at manufacturing of the standard CTMP that is commonly used. The fibre length of low energy CTMP from softwood can be adjusted to create the necessary opportunities for good formation on paperboard machines. Techniques to improve the internal bond strength in a CTMP based sheet structure by adding flexible chemical fibres and/or chemical additives are also known. The final main goal of the project is to find optimal furnishes and conditions on a paperboard machine in mill scale to be able to utilize the full potential of the developed low energy CTMP techniques. This includes studies to find conditions to reduce grammage in manufacturing of high quality paperboard products, which is an efficient indirect way to reduce both consumption of energy and resources. To achieve these goals it will be necessary to either improve the surface properties of fibres in the furnish by chemical additives or to increase the energy input somewhat in refining of the chemical pulp. Such techniques are available. In the project, the findings from initial studies in laboratory scale have to be confirmed in pilot plant and mill scale trials.