Process selection for chemimechanical pulping of aspen
The utilization of aspen in chemimechanical pulping increased significantly during the last decade. There are a number of technologies now available for chemimechanical pulping of aspen, the two most popular being BCTMP and APMP. The former involves impregnation with alkaline sulphite (AS) and the latter with alkaline peroxide (AP) chemicals. Results from these two processes have been previously reported on aspen chips in terms of pulp property/energy requirements , and intrinsic relationships . It is well understood that to reduce energy consumption in refiner mechanical pulping of aspen, some kind of alkali pre-treatment is needed . Over the course of the last decade, the use of alkaline peroxide in the chip impregnation stage(s) has seen an increase in both development and commercial application. A large number of alkaline chip impregnation studies at atmospheric refining conditions, such as APMP and APP, have been conducted on hardwood species [2,4-7]. The large increase in hardwood utilization by the paper industry during the 1990s is one explanation for the rapid progression to commercial installation of a number of BCTMP and APMP (APP) mills for use in market pulp and/or integrated printing paper applications. The installed hardwood chemimechanical market pulp capacity increased from less than 10% in 1989 to 54% of capacity by 1999 .
This paper reviews several process configurations available for alkaline peroxide mechanical pulping of aspen. The process configurations include atmospheric refining (APMP), pressurized refining (AP-TMP) and a combination of atmospheric and pressurized refining (P-RC). Results from the most recent configuration (P-RC) are presented and discussed in terms of pulp property development and compared to an APMP pulp series produced from the same aspen chip furnish.
Xu, E.C. and Sabourin, M.J., "Process selection for chemimechanical pulping of aspen" (2002). Aspen Bibliography. Paper 143.