Producing pulp and energy from wheat straw

The aim of this study was to evaluate the use of wheat straw as a raw material in simple biorefinery operations producing papermaking pulps and energy. The first option was to produce pulp for printing and writing papers by hot water treatment followed by alkaline peroxide bleaching. The second option was to produce unbleached pulp for packaging materials by a hot water treatment method, followed by mechanical refining. In both options residual materials are available for energy production, in the form of fines or dissolved solids. The results from the chemical approach showed that the optimum hot water treatment temperature is close to 100 C and acid is not needed in the stage. Less than 10% of wheat straw is dissolved in these hot water treatment conditions with a temperature below 130 C. Following alkaline bleaching it is possible to produce pulp with over ISO 75% brightness and a yield of over 50%. Paper properties of the resultant wheat straw pulp are relatively good. The results of the mechanical approach showed that 36% of the original wheat straw ends up in the fibre fraction between 30-100 mesh, 13% is coarse fines between 100-200 mesh and 41% of the original raw material is fine fines below 200 mesh. The papermaking properties of the fibre fraction thus obtained were relatively poor suggesting that they could only be used in mixtures with other pulps, or as such in moulded fibre packages