Accelerated Maceration of Compressed Spruce Wood Chips

Abstract

The rate of pulping of spruce wood depends on the pretreatment of wood chips. Current pretreatment methods that are being investigated and applied appear to be time-consuming and energy intensive. These drawbacks can be minimized by pretreating the chips through compression, perpendicular to the fibre direction. In the maceration process, it is currently very difficult to measure pulp characteristics in real time; therefore, different treatment times were selected for uncompressed and compressed chips. Maceration was carried out by boiling the chips in a solution of acetic acid and hydrogen peroxide mixed in a 1:1 ratio. Subsequently, the colour and lignin content of the maceration product were measured to demonstrate the accelerated maceration of compressed chips compared with uncompressed ones. The colour of the product obtained from compressed chips after 25 min of pulping was similar to that of holocellulose, while the lignin content was at the detection limit. Given the same pulping time, the product obtained from uncompressed chips was darker, more saturated, and contained a significantly higher amount of lignin. The compression of wood chips proved to be a promising pretreatment method for accelerating the maceration of spruce wood.