Alkali-Methanol-Anthraquinone pulping I Delignification rates and selectivity

Abstract

The AMA (alkali-methanol-anthraquinone pulping) process was invented by Z. Abe of Kyushu University in 1982. The Organocell process was improved and changed to the same pulping process as AMA process. On Sept. 1992, Organocell started up a 150, 000 ton/yr Organocell mill in Germany.
This investigation was carried out to get a better understanding about AMA. Delignification rates and selectivity in AMA were compared with these in kraft, alkali-methanol, and soda-anthraquinone pulping. Methanol extractives-free wood meal (24-48 mesh) of beech (Fagus crenata) and pine (Pinus densiflora) were used as raw materials. Each pulping was done under the same active alkali charge.
The results were summarized as follows :
(1) The delignification rate in AMA was faster than twice of that in kraft pulping.
(2) Methanol and anthraquinone, respectively, accelerated the delignification in AMA.
(3) Softwood as well as hardwood as raw materials was easily pulped by AMA.
(4) The selectivity of AMA was better than that of kraft, alkali-methanol, and soda-anthraquinone pulping.
(5) AMA process seems to be the best alternative to kraft pulping process.
(6) The main subjects on AMA process are left as follows ; washing process, bleaching process and sequences, mechanism of delignification and pulping, chemicals recovery process, economic evaluation.