Influence of bleaching sequences and conditions on Eucalyptus camaldulensis kraft pulp properties | |
| Author | Dang Thi Thanh Nhan |
| Call Number | AIT Thesis no.PP-05-11 |
| Subject(s) | Wood-pulp--Bleaching Eucalyptus camaldulensis Kraft paper |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | Eucalyptus kraft pulp was oxygen delignified from kappa 18.3 to 10.2 and then bleached with varying chlorine dioxide distribution, temperature and pH in Do stage. With conventional DoEpD1 sequence, the oxygen delignified pulp could reach the brightness of 89-90% ISO with kappa factor of 0.20 and chemical charge of 40 kg act.Cl/ADt. High pH (3.6) in the Do stage improved the brightness and brightness stability of pulp, lower pH (2.5) showed better selectivity, and more efficient HexA removal was found at pH 1.8. Hot temperature and long retention time in the DHT stage indicated more HexA removal, lower chemical consumption and better brightness stability, however lower viscosity. Kappa factor in DHT didn't affect significantly on pulp properties. HexA was unactive in peroxide and oxygen stages. HexA removal depended significantly on sequence. In "real" ECF sequence (DoEpD1), up to 94% of HexA could be removed and more than 50% of HexA was removed in the Do stage. Brightness and brightness reversion could be improved by replacing the D1 stage with D1+D2 stages or D1+P stages. "Slight" ECF sequence (Q(PO)DQ(PO)) could remove only 66% of HexA. Higher brightness and brightness stability was obtained compared to real ECF sequence. Strength properties were not affected markedly by kappa factor in the Do stage. The negative effect of the DHT stage was also marginal if any at an optimum kappa factor of 0.20. |
| Year | 2005 |
| 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) | Malinen, Raimo ; |
| Examination Committee(s) | Kolehmainen, Heikki ;Nazhad, Mousa M. ; |
| Scholarship Donor(s) | AIT Fellowship ;Agriculture Forestry University, Vietnam; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2005 |