| Author | Janetud Chawengsrethakul |
| Call Number | AIT Thesis no.PP-00-5 |
| Subject(s) | Wood-pulp--Bleaching
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of
Science |
| Publisher | Asian Institute of Technology |
| Abstract | Two stage oxygen delignification is one of the extended delignification methods that reduces kappa number of pulp entering bleaching plant. This makes it possible to reduce or eliminate chlorine-based bleaching chemical consumption as in bleaching. The benefits of high selectivity and reduction on environment impact have bring oxygen delignification to become a standard part in modem fiberline. The purpose of this study is to demonstrate the effect of two stage oxygen delignification on pulp of different kappa number, to evaluate pulp quality and to study the possibility for higher yield. Eucalyptus chips were cooked to four different kappa numbers range from 17 .2 to 42.1 and delignification was continued with one or two stage oxygen delignification to kappa number level, 10. After bleaching with D0EpD1 sequence pulps of 88 % brightness or higher has evaluated for strength properties. There are two critical transition points of kappa number, first between 15-17 and second 10- 11, in which viscosity has severe drop when passing these regions. Two stage oxygen delignification improved delignification for all high kappa number pulps. Yield should be benefit from better selectivity but no yield gain was obvious in this study. Pulp with kappa number between 25 to 30 is the best for oxygen delignification in terms of high viscosity, brightness and strength. |
| Year | 2000 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Pulp and Paper Technology (PP) |
| Chairperson(s) | Ruhanen, Mauno; |
| Examination Committee(s) | Malinen, Raimo 0. ;Kolehmainen, Heikki; |
| Scholarship Donor(s) | Government of Finland; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2000 |