EP0110683A1 - Bestimmung des Kochgrads in einem Sulfitkocher für Delignifizierung - Google Patents

Bestimmung des Kochgrads in einem Sulfitkocher für Delignifizierung Download PDF

Info

Publication number
EP0110683A1
EP0110683A1 EP83307188A EP83307188A EP0110683A1 EP 0110683 A1 EP0110683 A1 EP 0110683A1 EP 83307188 A EP83307188 A EP 83307188A EP 83307188 A EP83307188 A EP 83307188A EP 0110683 A1 EP0110683 A1 EP 0110683A1
Authority
EP
European Patent Office
Prior art keywords
digester
pressure
delignification
value
cooking
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP83307188A
Other languages
English (en)
French (fr)
Other versions
EP0110683B1 (de
Inventor
Ralph K. Johnson
Marion A. Keyes Iv
Azmi Kaya
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Babcock and Wilcox Co
Original Assignee
Babcock and Wilcox Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Babcock and Wilcox Co filed Critical Babcock and Wilcox Co
Publication of EP0110683A1 publication Critical patent/EP0110683A1/de
Application granted granted Critical
Publication of EP0110683B1 publication Critical patent/EP0110683B1/de
Expired legal-status Critical Current

Links

Images

Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C3/00—Pulping cellulose-containing materials
    • D21C3/22—Other features of pulping processes
    • D21C3/228—Automation of the pulping processes
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C3/00—Pulping cellulose-containing materials
    • D21C3/04—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides
    • D21C3/06—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides sulfur dioxide; sulfurous acid; bisulfites sulfites

Definitions

  • This invention relates to methods of and apparatus for determining the degree of cooking in a sulphite digester for delignification.
  • the invention can be used, for example, in the pulp industry.
  • Lignin is the major noncarbohydrate constituent of wood. It functions as a natural plastic binder for the cellulose fibres. Its exact formula is unknown. Lignin is removed from wood by both the sulphite and sulphate pulp processes.
  • the rate of delignification is a function of cooking liquor composition and cooking temperature, and that this rate increases rapidly with temperature and is affected by acid concentration. It is further known that the rate of delignification for acid pulping varies with temperature in accordance with the known Arrhenius equation.
  • the velocity factor reaction rate (k) can be determined from this equation and subsequently substituted in the standard rate of delignification equation to determine this latter rate.
  • the prior art is primarily concerned with processes associated with wood pulping delignification.
  • US Patent No. 3 523 060 discloses a modification of the sulphite pulping processes wherein a very large quantity of sulphur dioxide is utilised and the delignification step is forced by utilising a very high temperature.
  • US Patent No. 4 295 929 (Leithem) is directed to the same process, but in this case the proportion of combined sulphur dioxide used in the digestion process is varied as a function of the rate of heating. In essence, US 4 295 929 teaches that an increase in the proportion of sulphur dioxide used in the digestion process combined with an increase in the heating rate allows a considerable shortening of the total digestion time.
  • US 3 523 060 and US 4 295 929 are thus directed to variations of the sulphite digestion process in order to shorten the total digestion time.
  • US Patent No. 2 545 389 (Somer et al) discloses apparatus for increasing the sulphur dioxide content of the cooking acid used in the foregoing process. There is an inverse relation between sulphur dioxide content and total digestion time. US 2 545 389 is thus directed to the apparatus for increasing the sulphur dioxide content of the cooking acid rather than to the process itself.
  • a method of determining the degree of cooking in a delignification sulphite digester the method being characterised by sensing the digester temperature, sensing the digester pressure, providing values corresponding to a plurality of constants including an energy of activity constant for the digester reaction and the gas constant, continuously calculating the digester reaction rate of the sulphite digester as a function of digester temperature and pressure and the constants, to obtain a value thereof over time, obtaining a value corresponding to a partial pressure of sulphur dioxide in the digester as a function of digester pressure and temperature, multiplying the partial pressure of sulphur dioxide value by the reaction rate value to obtain a delignification rate value, and integrating the delignification rate value over a time to establish a value corresponding to the degree of cooking in the digester.
  • the invention also provides apparatus for accomplishing the foregoing method including individual function blocks which are connected together to achieve the various calculations.
  • apparatus for determining the degree of cooking in a sulphite digester for delignification the apparatus being characterised by:
  • a preferred embodiment of the present invention described hereinbelow provides a method and apparatus for calculating sulphite digester rate of delignification and determining the completion of cooking, utilising function blocks to continuously solve the so-called Arrhenius equation for the velocity factor reaction.
  • This calculation takes place in the first controller module with the second controller module being provided with function blocks to obtain a value corresponding to the rate of delignification.
  • the delignification rate is continuously computed and monitored, and when the cook has been brought up to a desired set point, an indication, such as an alarm, is provided to an operator to terminate the cooking process.
  • the preferred apparatus for and methods of determining the degree of cooking in a sulphite digester are simple in design, rugged in construction, and economical to manufacture.
  • the drawings show apparatus embodying the invention for determining the degree of cooking in a delignification sulphite digester.
  • the rate of delignification is primarily a function of the cooking liquor composition and cooking temperature. Since there are established mathematical expressions for the rate of delignification, it is possible to determine how much cooking time is required based upon the cooking temperature for a particular pulp quality. See Pulp and Paper Manufacture, 2nd Ed., Volume I, The Pulping of Wood, pp 282 to 285.
  • the rate of reaction is a little more than doubled by an increase of 10°C in temperature. Cooking is extremely slow at temperatures below 100°C.
  • Figure 1 illustrates how calculation of the digester rate of delignification and Kappa (K) Number can be implemented in a Bailey NETWORK 90 (Trade Mark) system. The entire delignification rate and K-number calculation can be accomplished using two NETWORK 90 controller modules 10, 30 for a particular digester. Information concerning the NETWORK 90 can be found in Bailey Controls Company Application Guide 260-2 and Bailey Controls Company Product Specification E93-906.
  • the Arrhenius equation can be continuously solved for the velocity factor reaction rate (k), by means of a calculator unit or module 23 shown in greater detail in Figure 2.
  • the calculation is based upon digester temperature measurement as determined by a digester temperature transmitter 12 which provides one of a plurality of inputs to the unit 23.
  • the partial pressure of sulphur dioxide in the digester is approximated by measuring the difference between steam pressure at the digester temperature and the actual digester pressure. This partial pressure is linearised and corrected for the assumption that the digester pressure is that of only steam and sulphur dioxide in equilibrium with the digester acid. Steam pressure is calculated as a function of temperature in a unit 14 and the actual pressure is supplied by a digester pressure transmitter 15. The difference between the steam pressure and digester pressure is taken in a comparator unit 16. The n power factor in Equation (2) is provided by a function generator 17 and provides a means for compensating for the foregoing assumption.
  • the constants A, E, 2.303 and R of Equation (1) are provided to the unit 23 by units 18, 19, 20 and 21, respectively.
  • An output (log k) from the unit 23 is integrated to provide k and multiplied by the partial pressure output value from the function generator 17 to provide an output from the controller module 10 which represents the rate of delignification at any instant for the sulphite digester, in accordance with Equation (2), and is directed to the second controller module 30.
  • the digester cook operator manually enters total S0 2 and free SO 2 acid strength chemical tests as inputs to the controller module 30 over units 32 and 33, respectively.
  • the controller automatically subtracts the difference, which become the combined S0 2 content, in a comparator unit 34.
  • the delignification rate can then have acid strength S0 2 correction applied over a function generator 35 and multipliers 36, 37.
  • the delignification rate will be integrated for each cook, in a unit 38, with respect to time, for totalising the area under the reaction curve of Figure 3.
  • This area totalisation is related to a degree of cooking (Kappa Number) set point for the particular grade.
  • Kappa Number degree of cooking
  • the degree of cooking (CD) is derived as follows:

Landscapes

  • Paper (AREA)
  • Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
  • Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)
EP83307188A 1982-11-24 1983-11-24 Bestimmung des Kochgrads in einem Sulfitkocher für Delignifizierung Expired EP0110683B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US44427282A 1982-11-24 1982-11-24
US444272 1982-11-24

Publications (2)

Publication Number Publication Date
EP0110683A1 true EP0110683A1 (de) 1984-06-13
EP0110683B1 EP0110683B1 (de) 1987-04-08

Family

ID=23764204

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83307188A Expired EP0110683B1 (de) 1982-11-24 1983-11-24 Bestimmung des Kochgrads in einem Sulfitkocher für Delignifizierung

Country Status (11)

Country Link
EP (1) EP0110683B1 (de)
JP (1) JPS59137584A (de)
KR (1) KR880000744B1 (de)
AU (1) AU2149983A (de)
BR (1) BR8306460A (de)
CA (1) CA1198858A (de)
DE (1) DE3370840D1 (de)
ES (1) ES527326A0 (de)
HK (1) HK95287A (de)
IN (1) IN159330B (de)
SG (1) SG60987G (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4978425A (en) * 1989-06-13 1990-12-18 Elsag International B.V. Method for controlling the degree of cooking in a digester
US4990219A (en) * 1989-06-13 1991-02-05 Elsag International B.V. Apparatus for controlling the degree of cooking in a digester
EP0445321A1 (de) * 1990-03-05 1991-09-11 Siemens Aktiengesellschaft Verfahren zur Herstellung von Zellstoff in einem kontinuierlichen Kocher
WO1997013916A2 (de) * 1995-10-09 1997-04-17 Siemens Aktiengesellschaft Verfahren zur bestimmung des endpunktes der zellstoffkochung und anordnung zum steuern der kochzeit bei der zellstoffkochung in einem reaktor
CN1064096C (zh) * 1994-04-28 2001-04-04 东芝株式会社 蒸煮锅温度分布控制系统

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3941649A (en) * 1972-07-14 1976-03-02 Mo Och Domsjo Aktiebolag Process for obtaining a predetermined Kappa number in sulfate pulping

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3941649A (en) * 1972-07-14 1976-03-02 Mo Och Domsjo Aktiebolag Process for obtaining a predetermined Kappa number in sulfate pulping

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
ABSTR. BULL. INST. PAPER CHEM., vol. 45, no. 4, October 1974, page 399, abstract no. 3756 (APPLETON, WISC., US) I.F. ZORIN et al.: "Control of the sulfite pulping process"; & BUMAZH. PROM. no. 5:19 (May 1974) *
ABSTR. BULL. INST. PAPER CHEM., vol. 52, no. 6, December 1981, page 714, abstract no. 6672 (APPLETON, WISC., US) & SE - C - 416 061 (MO OCH DOMSJO AB.) 24 November 1980 *
TAPPI J. TECHN. ASS. PULP PAPER IND., vol. 64, no. 8, August 1981 (ATLANTA, GA., US) E. JUTILA et al.: "Mathematical models for producing dissolving pulps", pages 105-108 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4978425A (en) * 1989-06-13 1990-12-18 Elsag International B.V. Method for controlling the degree of cooking in a digester
US4990219A (en) * 1989-06-13 1991-02-05 Elsag International B.V. Apparatus for controlling the degree of cooking in a digester
EP0445321A1 (de) * 1990-03-05 1991-09-11 Siemens Aktiengesellschaft Verfahren zur Herstellung von Zellstoff in einem kontinuierlichen Kocher
CN1064096C (zh) * 1994-04-28 2001-04-04 东芝株式会社 蒸煮锅温度分布控制系统
WO1997013916A2 (de) * 1995-10-09 1997-04-17 Siemens Aktiengesellschaft Verfahren zur bestimmung des endpunktes der zellstoffkochung und anordnung zum steuern der kochzeit bei der zellstoffkochung in einem reaktor
WO1997013916A3 (de) * 1995-10-09 1997-07-17 Siemens Ag Verfahren zur bestimmung des endpunktes der zellstoffkochung und anordnung zum steuern der kochzeit bei der zellstoffkochung in einem reaktor

Also Published As

Publication number Publication date
SG60987G (en) 1987-10-23
HK95287A (en) 1987-12-24
IN159330B (de) 1987-05-02
KR880000744B1 (ko) 1988-05-04
KR840006688A (ko) 1984-12-01
ES8505479A1 (es) 1985-05-16
JPS59137584A (ja) 1984-08-07
EP0110683B1 (de) 1987-04-08
DE3370840D1 (en) 1987-05-14
CA1198858A (en) 1986-01-07
BR8306460A (pt) 1984-06-26
ES527326A0 (es) 1985-05-16
AU2149983A (en) 1984-05-31

Similar Documents

Publication Publication Date Title
US4298955A (en) Method of and apparatus for the detection and analysis of hazards
US3490689A (en) Automated machine system
US4353118A (en) Apparatus for determining the throughflow in pipe conduits
EP0110683A1 (de) Bestimmung des Kochgrads in einem Sulfitkocher für Delignifizierung
US3711687A (en) Computer control of parallel paper mill refiners for controlling the freeness of stock by controlling the stock temperature rise through each refiner
US4013506A (en) Method and apparatus for automatically and simultaneously controlling solution viscosity and brightness of a pulp during multi-stage bleaching
US3941649A (en) Process for obtaining a predetermined Kappa number in sulfate pulping
US3537820A (en) Method of and apparatus for analyzing a chemical composition
US3465550A (en) Chromatic control of bleaching process
US6597959B1 (en) Method and device for controlling an essentially continuous process
US5436456A (en) Moisture meter curve calibration system
JPS5739319A (en) Display method for result of combinational operation
US4104028A (en) Method of titrating liquor
US3322616A (en) Pulp digester control apparatus
US4308099A (en) Nuclear reactor safety system
US3663805A (en) Method and apparatus for monitoring processes
US4218734A (en) Process quantity display apparatus
SE500994C2 (sv) Förfarande för styrning av en defibreringsprocess medelst mätning av den tillförda flisens bulkdensitet
Allison et al. Adaptive‐predictive control of kamyr digester chip level
US4162933A (en) Exothermic heat as a means of determining the degree of delignification
US6153050A (en) Method and system for controlling the addition of bleaching reagents to obtain a substantially constant percentage of pulp delignification across the first bleaching/delignifying stage
KR830001225B1 (ko) 원자로 안전시스템(system)
CN2482074Y (zh) 制浆蒸煮过程纸浆卡伯值在线光谱测量装置
JP3107178B2 (ja) クラフトパルプ酸素晒塔におけるプロセス同定装置
JP3107179B2 (ja) クラフトパルプ未晒洗浄装置におけるプロセス同定装置

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): DE FR GB IT

17P Request for examination filed

Effective date: 19841116

ITF It: translation for a ep patent filed
GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB IT

REF Corresponds to:

Ref document number: 3370840

Country of ref document: DE

Date of ref document: 19870514

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: 732

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19921021

Year of fee payment: 10

Ref country code: DE

Payment date: 19921021

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19921030

Year of fee payment: 10

ITTA It: last paid annual fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19931124

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19931124

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19940729

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19940802

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST