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US5060132A Expired / Lapsed US ⏱️ 0.0 years remaining

Method of modeling and control for delignification of pulping

Assignee: Elsag International BV
•
Filing: 1989-12-07
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Granted: 1991-10-22
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Expires: 2009-12-07
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Abstract

Abstract A method and apparatus for controlling the delignification process by monitoring and minimizing variations in the Kappa Number and the digester residual chemical concentration. A parameter representative of the H factor for the delignification process and a measurement of the initial chemical concentration are utilized to produce signals representative of the actual Kappa Number and the residual acid concentration in the digester. The expected perturbations in Kappa Number and the residual chemical concentration are compared with target values for same to produce estimated errors due to mismatch which are compared with actual measured errors for these parameters to produce compensated control errors for same. The compensated control errors are utilized to modify the target values for the H factor and the initial chemical concentration by modifying the chemical charge and the time versus temperature operating parameters of the digestings to regulate pulp Kappa number and spent cooking liquor residual chemical concentrations of the process.

Inventors

  • 👤 Jeffrey A. Beller
  • 👤 Ralph K. Johnson
  • 👤 Roger Kammerer
  • 👤 Azmi Kaya
  • 👤 Marion A. Keyes, IV

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-27 16:07
CPC Classifications
D; D21; D21C; D21C7/00; D21C7/12

Claims Analysis

Total Claims: 2
Claim 1
Independent Claim 166 words
A method for compensating an open loop operation in a supervisory feedback control path in a pulping delignification process, comprising the steps of: generating signals of expected perturbation in actual process output states, Kappa number, K a , and residual chemical concentration, R a ; comparing the expected perturbation signals to targeted perturbation signals, Kappa number, K t , and residual chemical concentration, R t ; producing model mismatch estimated error signals, e K and e R , from a difference in the targeted and expected perturbation signals; generating actual measured error signals, e K and e R , from a difference in predetermined desired values and measured values of Kappa number and residual chemical concentration; producing compensated control error signals, e' K and e' R , from a difference in the measured and estimated error signals; and controlling pulp Kappa number and liquor residual chemical concentration in the pulping delignification process from changes in the compensated error signals, e' K and e' r , respectively.
Claim 2
Independent Claim 166 words
A method for compensating an open loop operation in a supervisory feedback control path in a pulping delignification process, comprising the steps of: generating signals of expected perturbation in actual process output states, Kappa number, K a , and residual chemical concentration, R a ; comparing the expected perturbation signals to targeted perturbation signals, Kappa number, K t , and residual chemical concentration, R t ; producing model mismatch estimated error signals, e K and e R , from a difference in the targeted and expected perturbation signals; generating actual measured error signals, e K and e R , from a difference in predetermined desired values and measured values of Kappa number and residual chemical concentration; producing compensated control error signals, e' K and e' R , from a difference in the measured and estimated error signals; and controlling pulp Kappa number and liquor residual chemical concentration in the pulping delignification process from changes in the compensated error signals, e' K and e' r , respectively.

References Cited (Backward Citations)

US4213175A Cited
US4719561A Cited
US4725942A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1994-10-21 1995-04-22 1995-10-22 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1998-10-21 1999-04-22 1999-10-22 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2002-10-21 2003-04-22 2003-10-22 $7700.00 Window Closed / Lapsed

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