Adaptation of an existing O2 stage to Strong Alkaline Treatment (SAT) when iming at production of dissolving-like hardwood pulps | |
| Author | Supanee Phiphatwitthaya |
| Subject(s) | Water--Dissolved oxygen Hardwoods |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Pulp and Paper Technology, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | This Thesis deals with an attempt to produce dissolving-like Eucalyptus Kraft pulps. Instead of using the pre-hydrolyses step, the mill pulp after Kraft Cooking was subjected to a strong alkali treatment (SAT) in which the treatment conditions were widely varied. This step was used instead of O2-delignification. So treated pulps were then D EP D bleached to a brightness level close to 90% ISO. It is shown that it is possible to produce dissolving-like Eucalyptus pulps with high final brightness, suitable pulp viscosity and with interesting dissolving pulp properties (pentosans and alpha-cellulose contents) without pre-hydrolyses of the Kraft pulp. It is further shown that the O2 delignification stage can be converted to hot caustic extraction by substantially increasing the alkalinity in this stage. For the best process-economy, the temperature in the SAT stage should be between 40 and 80oC and the alkali level should be around 400 kg/tp. However for achieving the most suitable quality parameters for the bleached dissolving pulp-like pulps (low enough kappa number i.e. lignin content, low enough pentosan content i.e. hemicelluloses and high enough alpha-cellulose content), the alkalinity in the SAT-step should be increased and higher temperature than 40C should be applied. It is recommended to measure also dissolving pulp’s filterability (the Kw number) and cellulose reactivity (the Fock’s number) in order to avoid any unnecessary sub-optimization efforts. |
| Year | 2013 |
| 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) | Nazhad, Mousa M.; |
| Examination Committee(s) | Bohez, Erik L. J.;Yakupitiyage, Amararatne;Basta, Jiri; |
| Scholarship Donor(s) | Royal Thai Government;AIT Fellowship; |