ACETOCELL - AN INNOVATIVE PROCESS FOR PUL PING, TOTALLY FREE FROM SULFUR AND CHLORINE

The ACETOCELL process has been developed by VEBA OEL (oil) from the Ac etosolv concept according to Nimz et al. The process makes the pulping of soft and hardwoods possible with the aid of acetic acid at high te mperature without added catalysts. The delignification hereby achieved can be extended to Kappa numbers 16-20 at high yields in the case of e.g. Spruce (Picea abies Karst). Subsequent Ozone bleaching in an acet ic acid acidified medium leads to a further reduction of the Kappa num ber to less than 2. Combined with a final extraction stage and Hydroge n peroxide bleaching without chelating additives. this permits the pro duction of high whiteness pulps (80-85% ISO), with good mechanical pro perties. The extension of the sulphur and chlorine-free ACETOCELL proc ess to the technical scale is presently being carried out in a Technik um plant, using wood chips. Besides the processing of wood chips, the ACETOCELL process makes it possible to pulp annual plants. This has be en demonstrated by pu ping Chinese reeds (Miscanthus sinensis giganteu s), also in the Technikum plant. The results and studies on paper tech nological applications of the ACETOCELL pulps are reported. That these pulps are suitable for chemical manufacturing has been shown by labor atory experiments on etherification and viscose-conversion.