High Selectivity Oxygen Delignification
- Georgia Institute of Technology
The overall objective of this program was to develop improved extended oxygen delignification (EOD) technologies for current U.S. pulp mill operations. This was accomplished by: (1) Identifying pulping conditions that optimize O and OO performance; (2) Identifying structural features of lignin that enhance reactivity towards EOD of high kappa pulps; (3) Identifying factors minimizing carbohydrate degradation and improve pulp strength of EOD high kappa pulps; (4) Developing a simple, reproducible method of quantifying yield gains from EOD; and (5) Developing process conditions that significantly reduce the capital requirements of EOD while optimizing the yield benefits. Key research outcomes included, demonstrating the use of a mini-O sequence such as (E+O)Dkf:0.05(E+O) or Dkf:0.05(E+O)(E+O) without interstage washing could capture approximately 60% of the delignification efficiency of a conventional O-stage without the major capital requirements associated with an O-stage for conventional SW kraft pulps. The rate of formation and loss of fiber charge during an O-stage stage can be employed to maximize net fiber charge. Optimal fiber charge development and delignification are two independent parameters and do not parallel each other. It is possible to utilize an O-stage to enhance overall cellulosic fiber charge of low and high kappa SW kraft pulps which is beneficial for physical strength properties. The application of NIR and multi-variant analysis was developed into a rapid and simple method of determining the yield of pulp from an oxygen delignification stage that has real-world mill applications. A focus point of this program was the demonstration that Kraft pulping conditions and oxygen delignification of high and low-kappa SW and HW pulps are intimately related. Improved physical pulp properties and yield can be delivered by controlling the H-factor and active alkali charge. Low AA softwood kraft pulp with a kappa number 30 has an average improvement of 2% in yield and 4 cP in viscosity in comparison to high AA pulp for the oxygen delignification. This difference is also seen for high-kappa SW kraft pulps with an average improvement of {approx}3% in yield and 3 cP in viscosity for low AA high kappa number 50 pulp. Low AA hardwood kappa number 20 pulp had an average improvement of {approx}4% in yield and 6-12 cP in viscosity as compared to high AA pulp. Lower kraft cooking temperature (160 vs. 170 C) in combination with the medium AA provides a practical approach for integrating high kappa pulping of hardwoods (i.e., low rejects) with an advanced extended oxygen delignification stage. ECF pulp bleaching of low and high kappa kraft SW and HW pulps exhibit comparable optical and physical strength properties when bleached D(EPO)D.
- Research Organization:
- Arthur J. Ragauskas/Georgia Institute of Technology
- Sponsoring Organization:
- USDOE Office of Industrial Technologies (OIT) - (EE-20)
- DOE Contract Number:
- FC36-00ID13870
- OSTI ID:
- 859934
- Report Number(s):
- DOE/13870
- Country of Publication:
- United States
- Language:
- English
Similar Records
Experiences with extended delignification of hardwood and softwood kraft pulp in a continuous digester
High-efficiency chlorine dioxide delignification. Summary of progress, April 1--June 30, 1998
Mill Designed Bio bleaching Technologies
Journal Article
·
Thu Oct 31 23:00:00 EST 1985
· Tappi; (United States)
·
OSTI ID:5468499
High-efficiency chlorine dioxide delignification. Summary of progress, April 1--June 30, 1998
Technical Report
·
Fri Jul 31 00:00:00 EDT 1998
·
OSTI ID:656575
Mill Designed Bio bleaching Technologies
Technical Report
·
Thu Jan 29 23:00:00 EST 2004
·
OSTI ID:828216