ECF bleaching of tropical hardwood kraft pulp with pressurized peroxide (PO) stage | |
| Author | Karim, Md. Rezaul |
| Call Number | AIT Thesis no.PP-00-8 |
| Subject(s) | Kraft paper industry--Vietnam Wood-pulp--Bleaching--Vietnam |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science |
| Publisher | Asian Institute of Technology |
| Abstract | The main objective of this thesis was to study the efficiency of pressurized peroxide (PO) stage in ECF bleaching on eucalyptus kraft pulp and compare it with conventional ECF bleaching in terms of brightness, paper properties and economic point of view. To fulfill this goal, pulp was produced from Eucalyptus camaldulensis by kraft pulping process and oxygen delignification was done. Two ECF bleaching sequences, D0ED1ED2 and D0EμQ(PO) were chosen for bleaching the oxygen-delignified pulp. The first sequence was used as reference. The extraction stage of examined sequence was reinforced with hydrogen peroxide. In (PO) stage of this sequence, various peroxide charges, temperatures and alkali charges were applied. A total eighteen pulps were bleached by DoEpQ(PO) sequence from the combination of three variables in (PO) stage and one as reference pulp. Hand sheets were made from ten of those eighteen pulps and reference pulp. Then paper properties were measured. The response of the use of peroxide in both the extraction and (PO) stages to eucalyptus kraft pulp was identical. An application of 0.5% peroxide in first extraction stage results 7% ISO higher brightness compared to reference sequence. Pulps treated at high temperature in (PO) stage possessed higher brightness but lower viscosity and yield compared to reference pulp at all peroxide and alkali charges. But at low temperature, brightness and viscosity were not affected significantly. Peroxide and alkali charges in (PO) stage showed also significant effect on pulp brightness, viscosity and bleaching yield. There were no big variations in paper properties of peroxide treated pulps among themselves, and reference pulp as well. Most of the pulps, treated in (PO) stage showed strength and optical properties close to reference pulp. The use of peroxide ECF bleaching reduced the use of ClO2 by about 40% compared to conventional ECF sequence. Lower AOX in bleaching effluent might be resulted from this. |
| 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) | Kolehmainen, Heikki ;Malinen, Raimo O.; |
| Scholarship Donor(s) | Government of Japan; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2000 |