Control scheme for rapid pulp delignification and bleaching

OTHER PUBLICATIONS

Kappel et al. "High-consistency ozone-bleaching technology". Tappi Journal. 1994. vol. 77, No. 6, pp. 109-116. M. Ollila, "Chemical Pulp Bleaching Control Based on Inline Brightness and Residual Measurements Before and After Stage," Tappi Porceedings, 1988 Pulping Conferences, pp. 603-608 1988.

White et al., "Importance of Reactor Design in High Consistency Ozone Bleach," Pulp & Paper Canada, vol. 94, No. 9, pp. 242-247 (1993) 1993.

R.P. Singh, "Ozone Replaces Chlorine in the First Bleaching
Stage," Tappi, vol. 64, No. 2, pp. 45-48 (Feb. 1982) 1982.
U. Germgard et al., "Ozone Prebleaching of a Modified-
Cooked and Oxygen-Bleached Softwood Kraft Pulp,"
Svensk Papperstidning, No. 15, 1985, pp. 127-132 1985.
Part et al, "Use of Ozone for Pulp Bleaching," 42(10A):
V14-23 (Oct. 1988) 1988.

Seymour et al, 'Testing and Control in Bleach Plants,"
Bleaching of Pulp, Tappi, 3rd edition, p. 478. 1979 1979.
Liebergott et al., "02, 03 and Peroxide", Seminar Notes,
1978, Pulping and Bleaching Seminar, pp. 90-105.
Singh, "Computer Control", The Bleaching of Pulp, Tappi
Press, 1979, pp. 503-513.

Burnett, "Computer Control of the Chlorine Stage", Pulp and Paper Magazine of Canada, vol. 71, No. 14, Jul. 17, 1970, pp. 57-62.

H. deV. Partridge, "Pulp & Paper Technology: New Pulp Bleaching Developments," pp. 45-50, Jun. 1976, CEP. . J.K. Perkins et al., "Advances in Ozone Bleaching —Part EL" pp. 263-266.

G.A. Smook, Handbook for Pulp & Paper Technologists, pp. 154-172, Tappi.

John S. Fujii te al., "Oxygen Pulping of Hardwoods," pp. 1-12.

K.H. Ferguson, "Union Camp Begins Ozone Era with New Kraft Bleaching Line at Franklin, Va.," Nov. 1992, pp. 42-55, Pulp & Paper.

F.G. Shinskey, Process Control Systems —Application, Design, and Tuning, Third Edition, pp. 4-7, 10-11, 14-15, 18-19, 42-43, 120-121, 1988, McGraw-Hill.

A. G. Jamieson et al., 'Washing System," May 1973, pp. 187-191, Svensk Papperstidning.

B. S. Kirk et al., "Low-Consistency Oxygen Delignification in a Pipeline Reactor," May 1978, pp. 77-80, Tappi, vol. 61, No. 5.

Primary Examiner—Anthony J. Weier

Attorney, Agent, or Firm—Nath & Associates; Gary M.

Nath; Suet Chong

162/65 B

A process control for adjusting bleaching agent application in response to the pulp brightness and/or K number is realized by utilizing a coupled control feedforward and/or feedback control system or combination thereof wherein brightness measurements are made between successive K number measurements and adjustments made to the bleaching agent application in response to a comparison value.

16 Claims, 7 Drawing Sheets