CA1049713A - Recovering turpentine and heat from black liquor from a continuous digestor - Google Patents
Recovering turpentine and heat from black liquor from a continuous digestorInfo
- Publication number
- CA1049713A CA1049713A CA229,293A CA229293A CA1049713A CA 1049713 A CA1049713 A CA 1049713A CA 229293 A CA229293 A CA 229293A CA 1049713 A CA1049713 A CA 1049713A
- Authority
- CA
- Canada
- Prior art keywords
- liquor
- expansion
- digesting
- vapors
- precursor
- 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.)
- Expired
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
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- Paper (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method of recovering turpentine and heat in connection with the evaporation of black liquor emerging from a continuous-working cellulose digester at a high temperature and under high pressure, wherein the black liquor is evaporated by expansion and vapors derived from the expansion evaporation of the black liquor are brought into an indirect heat exchange contact with the digesting liquor or with a precursor thereof in order to concentrate the latter.
A method of recovering turpentine and heat in connection with the evaporation of black liquor emerging from a continuous-working cellulose digester at a high temperature and under high pressure, wherein the black liquor is evaporated by expansion and vapors derived from the expansion evaporation of the black liquor are brought into an indirect heat exchange contact with the digesting liquor or with a precursor thereof in order to concentrate the latter.
Description
~04g713 Method of recovering turpentine and he~t in con-nection with expansion evaporation of black liquor which is removed from a continuous-working cellulose digester at a high temperature and under high pressure.
The present invention relates to a method of r~-covering turpentine and heat in connection with the evap-oration of black liquor which is removed from a continuous-working cellulose digester at a high temperature and under high pressure, ~he black liquor being evaporated by expansion.
In a cellulose mill the ~i~esting agent is pre-pared by dissolving in water the melt obtained from the soda-ash roaster. The solution thereby obtained, called green liquor, is clarified and treated with calcium hydroxide.
' This treatment with calcium hydroxide is called caustic~zation.
i In the causticization the sodium carbonate of the green liquor reacts with the calcium hydroxide, and sodium hydrox de and calcium carbonate are produced. At the final stage of , the causticization the calcium carbonate is separated by -filtration or in a sedimentation tank, and what is left is the digesting agent called white liquor.
Green liquor is usually a saturated solution. The ~, solubility of sodium hydrox~de is considerably greater than ~I that of sodium carbonate. For this reason, white liquor is ;~l usually not a saturated solution. It can be evaporated to i ~' a certain degree without causing crystallization. The w~ite liquor is combined with wood chips and thereafter the actual I digestion is performed. The digestion takes place in a .. ~ ....
digester at a temperature of approx. 170C.~ After the digestion the flbers and the dissolved substances are separated from each other in a washer.
After the wash the fibers are taken to the bleaching I
.
:
:, .. : ~ . . , -........ :
1049~3 unit, where they are bleached with chlorine chemicals, The liquor, called black liquor, separated from the fibers during the washing stage, contains dissolved sub-stances and inoganic chemical residues. The black liquor is evaporated to a dry matter content of approx. 60% and then burned in the soda-ash roaster.
In the bleaching unit the fiber~ are treated with chlorine chemicals and sodium hydroxide. In U.S. Pat.
3 698 995 it is suggested that the bleaching waste waters be used as washing water in the cellulose wash. Thereby the bleaching waste waters do not pollute nature and their combustion value can be utiliæed since the wastes go into the soda-ash roaster to be burned together with the black liquor.
However, sodium chloride thereby enters the liquor system, approx. 120 kg of sodium chloride per each tone of cellulose. Since the liquor system is a closed system, this ;~
chloride quantity must be removed to prevent the chloride content from reaching high values.
Canadian Pat. 915 362 suggests that sodl~m chloride be removed from the white liquor by evaporation crystalliza-tion.
It has also been previously suggested that sodium chloride be removed, after sodium carbonate has been re-¦ moved, from the liquor obtained from green liquor. The , sodium carbonate is removed b~ evaporation crystallization ~ or by cooling crystallization. The sodium chloride is :J, removed from the remaining solution , 30 i'' ~ ' ~ - 2 1049~713 by evaporation crystallization.
In a continuous-working KAMYR digester unit the temperature of the black liquor is approx. 160C when taken out of the digester. The heat present in this liquor is recovered by feeding the black liquor into the first expansion tank, and the vapor obtained from the expansion tank at approx. 120C.
is used for roasting or pre-heating wood chips and for removing air from the same. Thereafter the black liquor is fed into the second expansion tank and the obtained vapor is generally used for heating water.
Such a use of the heat energy of the black liquor is not the best possible. In addition, the removal of air in the roasting is poor since the high pressure in the roaster (approx. 2 atm) compresses the air present in the chips, in which case it cannot be removed.
It would be preferable if the roasting could be performed, at least initially, under atmospheric pressure.
Air removal would be more effective in this case. Such systems have been proposed but they are based on feeding the vapor obtained from the black liquor into the roaster. Such a vapor contains gases with unpleasant odors, for which reason it has been necessary to use expensive, air-tight roasters.
The object of the present invention is to intro-duce a method for an effective utilization of the expansion ~, vapor es~pecially in connection with the removal of sodium chloride, while the roasting is simultaneously made more effective and more economical.
, The present invention provides, in evaporating black liquor from a continuously operated cellulose digester, a method of recovering turpentine and heat by expansion evaporating vapors from the black liquor and bringing the vapors into indirect heat exchange with digesting liquor or ~ A
.. .. - . .. ~ .... .. - . -. . ~ . . .
.. ~ . . . . .. ~ .
- digesting liquor precursor for concentrating it, a part of the vapors derived from the liquor concentration being fed to a chip steaming step.
The vapors are preferably brought into indirect heat exchange-with a digesting liquor precursor. The digesting liquor or digesting liquor precursor is preferably concentrated in at least two successive stages with expansion vapors which are derived from the respective expansion evaporation stages of black liquor expansion evaporation performed in an equal number of stages.
It is also preferred that the chips be first steamed under normal pressure and thereafter under a slightly increased pressure. ~ -According to a further preferred feature of the - -present invention, the method is used in connection with the ., .
`' expansion evaporation of black liquor containing spent digesting liquor and washing solution from chlorine bleaching, wherein white liquor or white liquor precursor is concentrated in such a manner that sodium cloride is crystallized from the white liquor or from the white liquor precursor, and the precipitated sodium chloride crystals are separated from the white liquor or from the white liquor precursor before it is fed to the digestion.
The invention is described below in more detail with reference to the enclosed drawings, in which Fig. 1 depicts a schematic side view of a conventional system, in which white liquor and chips roasted with vapor derived from the expansion evaporation of black liquo~ are mixed before digesting. Fig. 2 depicts a schematic side view of a system meant for carrying out the method according to the invention;
in this system the white liquor is concentrated by means of -expansion vapor before J A~ -3a-J
~049713 mixing the white liquor with the chips, the chips having been roasted with vapor derived from the concentration of the white liquor. Fig. 3 depicts a preferred embodiment of the invention, in which the white liquor is concentrated in two stages in order ;-to crystallize the sodium chloride.
In Figs. 1-3 the numbers refer to the following parts: 1 is a continuous-working cellulose digester com-prising a digestion zone 6 and a washing zone 7. White liquor is fed from a~ove into the ~igester 1 through pipe 14, and washing liquor is fed into it from below through pipe 17, and vapor is fed into the digestion 6 and washing 7 zones through p~pe 15. Black liquor is removed from the middle of the digester 1 through pipe 8 and digeste~
cellulose is removed from below along pipe 16. Black liquor is directed along pipe 8 to the first expansion stage 2 and from there further along pipe 9 to the second expansion -~
stage 3, from wheEe black liquor is fed to the evaporation of bla~k liquor. The expansion vapors are removed from stage 2 along pipe 12 and from';stage 3 along pipe 11.
Number 4 refers to the feeding funnel for the chips and 5 to the roaster.
Number 13 indicates the feeding pipe for white liquor and 13', 13" and 13''' the feeding pipes for con-centrated ~hite liquor, in which case the sodium salt crystals have been removed from the white liquor in a separator 24. The crystals are removed from the separator 24 through pipe 25.
Number 18 in Fig. 2 refers to the white liquor 13 evaporator which is heated with expansion vapor 12, and the vapor emerging from the evaporator is fed along pipe 12' into the chip funnel 4.
~49~713 Numbers 19 and 20 indicate the evaporation crystal-lization devices for white liquor 13; the first of them is heated with expansion vapor 12 and additional vapor from pipe 21, the second one with expansion vapor 11 and vapor fed from the device 19 along pipe 22, and the vapor is removed from the second one along pipe 23.
Fig. 2 illustrates how an odorless evaporate 12' is obtained by evaporating 18 white liquor 13 by means of expansion vapor 12: this evaporate can be used in an open roaster 4. The system is simple. The black liquor is expanded at stage 2 at approx. 130C. The vapor 12 thereby obtained is used for the pre-evaporation of the white liquor 13 in the device lB. The chips are preheated with the obtained evaporate up to 100C in an open tank 4. If ~-it is considered advisable to raise the temperature of the chips further, it is necessary to use a pressure tank 5.
Expansion vapor, for example, can be used for this heating.
The pressure tank 5 required for the final heating can be considerably sm~ller than the ones in current use, since the temperature is raised only from 100C to 120C compared with the conventional system (5 in Fig. 1), in which the temperature is raised from 10C to 120C in the pressure tank.
When evaporation crystallization devices are in-cluded in the liquor system as described above, it is advantageous to use expansion vapor for the crystallization.
I Fig. 3 illustrates such a system. In this system, partly expansion vapor 11 and 12 and partly additional vapor 21 obtained from elsewhere are used for the crystallization 19 and 20. Vapor is fed to the roasting from the first - -crystallization device 19. The use of expansion vapor 11 and 12 in the crystallization devices 19 and 20 is ad-( " , . . , , , , : ~ : ~
,: . ~ ,` , - ,- - -10497~3 vantageous since it is not always possible to place the crystallization units 19 and 20 in a series with the black liquor evaporation unit. For example, in the known methods referred to above, this is prevented by the great rise of the boiling point of the white liquor. The additional vapor required in crystallization can be reduced by approx. 50%
by effectively using the expansion vapor according to the present invention.
When a concentrated digesting liquor 13''' is ob-tained by pre-evaporation or crystallization, the consumption ; of vapor in the act~al digestion is reduced. Normally the temperature of the digesting liquor is approx. 90C when it is fed to the digestion stage 6. The digestion temperature is approx. 170C. When the digesting liquor is concentrated before the digestion, the liquid quantity to be heated from 90C to 170C before digestion is amaller, which saves energy.
The black liquor 8 is reduced by the quantity of water evaporated from the digesting liquor, Thereby the consumption~f vapor in the black liquor evaporation unit is reduced.
By concentrating the digesting liquor, vapor is saved both in the b~ack liquor evaporation1unit and the ~igestion unit 6. The digesting liquor can be concentrated by us~ng expansion vapor and the evaporate can be fed to the roasting, in which case the pre-evaporation does not increase the consumption of vapor.
When all the condensates from the expansion vapor are recovered, the yield of turpentine is also increased.
In a conventional system, part of the expansion vapor con-I denses in the roaster, i~ which case this part of the turpen-tine cannot be recovered.
.
.. .
The present invention relates to a method of r~-covering turpentine and heat in connection with the evap-oration of black liquor which is removed from a continuous-working cellulose digester at a high temperature and under high pressure, ~he black liquor being evaporated by expansion.
In a cellulose mill the ~i~esting agent is pre-pared by dissolving in water the melt obtained from the soda-ash roaster. The solution thereby obtained, called green liquor, is clarified and treated with calcium hydroxide.
' This treatment with calcium hydroxide is called caustic~zation.
i In the causticization the sodium carbonate of the green liquor reacts with the calcium hydroxide, and sodium hydrox de and calcium carbonate are produced. At the final stage of , the causticization the calcium carbonate is separated by -filtration or in a sedimentation tank, and what is left is the digesting agent called white liquor.
Green liquor is usually a saturated solution. The ~, solubility of sodium hydrox~de is considerably greater than ~I that of sodium carbonate. For this reason, white liquor is ;~l usually not a saturated solution. It can be evaporated to i ~' a certain degree without causing crystallization. The w~ite liquor is combined with wood chips and thereafter the actual I digestion is performed. The digestion takes place in a .. ~ ....
digester at a temperature of approx. 170C.~ After the digestion the flbers and the dissolved substances are separated from each other in a washer.
After the wash the fibers are taken to the bleaching I
.
:
:, .. : ~ . . , -........ :
1049~3 unit, where they are bleached with chlorine chemicals, The liquor, called black liquor, separated from the fibers during the washing stage, contains dissolved sub-stances and inoganic chemical residues. The black liquor is evaporated to a dry matter content of approx. 60% and then burned in the soda-ash roaster.
In the bleaching unit the fiber~ are treated with chlorine chemicals and sodium hydroxide. In U.S. Pat.
3 698 995 it is suggested that the bleaching waste waters be used as washing water in the cellulose wash. Thereby the bleaching waste waters do not pollute nature and their combustion value can be utiliæed since the wastes go into the soda-ash roaster to be burned together with the black liquor.
However, sodium chloride thereby enters the liquor system, approx. 120 kg of sodium chloride per each tone of cellulose. Since the liquor system is a closed system, this ;~
chloride quantity must be removed to prevent the chloride content from reaching high values.
Canadian Pat. 915 362 suggests that sodl~m chloride be removed from the white liquor by evaporation crystalliza-tion.
It has also been previously suggested that sodium chloride be removed, after sodium carbonate has been re-¦ moved, from the liquor obtained from green liquor. The , sodium carbonate is removed b~ evaporation crystallization ~ or by cooling crystallization. The sodium chloride is :J, removed from the remaining solution , 30 i'' ~ ' ~ - 2 1049~713 by evaporation crystallization.
In a continuous-working KAMYR digester unit the temperature of the black liquor is approx. 160C when taken out of the digester. The heat present in this liquor is recovered by feeding the black liquor into the first expansion tank, and the vapor obtained from the expansion tank at approx. 120C.
is used for roasting or pre-heating wood chips and for removing air from the same. Thereafter the black liquor is fed into the second expansion tank and the obtained vapor is generally used for heating water.
Such a use of the heat energy of the black liquor is not the best possible. In addition, the removal of air in the roasting is poor since the high pressure in the roaster (approx. 2 atm) compresses the air present in the chips, in which case it cannot be removed.
It would be preferable if the roasting could be performed, at least initially, under atmospheric pressure.
Air removal would be more effective in this case. Such systems have been proposed but they are based on feeding the vapor obtained from the black liquor into the roaster. Such a vapor contains gases with unpleasant odors, for which reason it has been necessary to use expensive, air-tight roasters.
The object of the present invention is to intro-duce a method for an effective utilization of the expansion ~, vapor es~pecially in connection with the removal of sodium chloride, while the roasting is simultaneously made more effective and more economical.
, The present invention provides, in evaporating black liquor from a continuously operated cellulose digester, a method of recovering turpentine and heat by expansion evaporating vapors from the black liquor and bringing the vapors into indirect heat exchange with digesting liquor or ~ A
.. .. - . .. ~ .... .. - . -. . ~ . . .
.. ~ . . . . .. ~ .
- digesting liquor precursor for concentrating it, a part of the vapors derived from the liquor concentration being fed to a chip steaming step.
The vapors are preferably brought into indirect heat exchange-with a digesting liquor precursor. The digesting liquor or digesting liquor precursor is preferably concentrated in at least two successive stages with expansion vapors which are derived from the respective expansion evaporation stages of black liquor expansion evaporation performed in an equal number of stages.
It is also preferred that the chips be first steamed under normal pressure and thereafter under a slightly increased pressure. ~ -According to a further preferred feature of the - -present invention, the method is used in connection with the ., .
`' expansion evaporation of black liquor containing spent digesting liquor and washing solution from chlorine bleaching, wherein white liquor or white liquor precursor is concentrated in such a manner that sodium cloride is crystallized from the white liquor or from the white liquor precursor, and the precipitated sodium chloride crystals are separated from the white liquor or from the white liquor precursor before it is fed to the digestion.
The invention is described below in more detail with reference to the enclosed drawings, in which Fig. 1 depicts a schematic side view of a conventional system, in which white liquor and chips roasted with vapor derived from the expansion evaporation of black liquo~ are mixed before digesting. Fig. 2 depicts a schematic side view of a system meant for carrying out the method according to the invention;
in this system the white liquor is concentrated by means of -expansion vapor before J A~ -3a-J
~049713 mixing the white liquor with the chips, the chips having been roasted with vapor derived from the concentration of the white liquor. Fig. 3 depicts a preferred embodiment of the invention, in which the white liquor is concentrated in two stages in order ;-to crystallize the sodium chloride.
In Figs. 1-3 the numbers refer to the following parts: 1 is a continuous-working cellulose digester com-prising a digestion zone 6 and a washing zone 7. White liquor is fed from a~ove into the ~igester 1 through pipe 14, and washing liquor is fed into it from below through pipe 17, and vapor is fed into the digestion 6 and washing 7 zones through p~pe 15. Black liquor is removed from the middle of the digester 1 through pipe 8 and digeste~
cellulose is removed from below along pipe 16. Black liquor is directed along pipe 8 to the first expansion stage 2 and from there further along pipe 9 to the second expansion -~
stage 3, from wheEe black liquor is fed to the evaporation of bla~k liquor. The expansion vapors are removed from stage 2 along pipe 12 and from';stage 3 along pipe 11.
Number 4 refers to the feeding funnel for the chips and 5 to the roaster.
Number 13 indicates the feeding pipe for white liquor and 13', 13" and 13''' the feeding pipes for con-centrated ~hite liquor, in which case the sodium salt crystals have been removed from the white liquor in a separator 24. The crystals are removed from the separator 24 through pipe 25.
Number 18 in Fig. 2 refers to the white liquor 13 evaporator which is heated with expansion vapor 12, and the vapor emerging from the evaporator is fed along pipe 12' into the chip funnel 4.
~49~713 Numbers 19 and 20 indicate the evaporation crystal-lization devices for white liquor 13; the first of them is heated with expansion vapor 12 and additional vapor from pipe 21, the second one with expansion vapor 11 and vapor fed from the device 19 along pipe 22, and the vapor is removed from the second one along pipe 23.
Fig. 2 illustrates how an odorless evaporate 12' is obtained by evaporating 18 white liquor 13 by means of expansion vapor 12: this evaporate can be used in an open roaster 4. The system is simple. The black liquor is expanded at stage 2 at approx. 130C. The vapor 12 thereby obtained is used for the pre-evaporation of the white liquor 13 in the device lB. The chips are preheated with the obtained evaporate up to 100C in an open tank 4. If ~-it is considered advisable to raise the temperature of the chips further, it is necessary to use a pressure tank 5.
Expansion vapor, for example, can be used for this heating.
The pressure tank 5 required for the final heating can be considerably sm~ller than the ones in current use, since the temperature is raised only from 100C to 120C compared with the conventional system (5 in Fig. 1), in which the temperature is raised from 10C to 120C in the pressure tank.
When evaporation crystallization devices are in-cluded in the liquor system as described above, it is advantageous to use expansion vapor for the crystallization.
I Fig. 3 illustrates such a system. In this system, partly expansion vapor 11 and 12 and partly additional vapor 21 obtained from elsewhere are used for the crystallization 19 and 20. Vapor is fed to the roasting from the first - -crystallization device 19. The use of expansion vapor 11 and 12 in the crystallization devices 19 and 20 is ad-( " , . . , , , , : ~ : ~
,: . ~ ,` , - ,- - -10497~3 vantageous since it is not always possible to place the crystallization units 19 and 20 in a series with the black liquor evaporation unit. For example, in the known methods referred to above, this is prevented by the great rise of the boiling point of the white liquor. The additional vapor required in crystallization can be reduced by approx. 50%
by effectively using the expansion vapor according to the present invention.
When a concentrated digesting liquor 13''' is ob-tained by pre-evaporation or crystallization, the consumption ; of vapor in the act~al digestion is reduced. Normally the temperature of the digesting liquor is approx. 90C when it is fed to the digestion stage 6. The digestion temperature is approx. 170C. When the digesting liquor is concentrated before the digestion, the liquid quantity to be heated from 90C to 170C before digestion is amaller, which saves energy.
The black liquor 8 is reduced by the quantity of water evaporated from the digesting liquor, Thereby the consumption~f vapor in the black liquor evaporation unit is reduced.
By concentrating the digesting liquor, vapor is saved both in the b~ack liquor evaporation1unit and the ~igestion unit 6. The digesting liquor can be concentrated by us~ng expansion vapor and the evaporate can be fed to the roasting, in which case the pre-evaporation does not increase the consumption of vapor.
When all the condensates from the expansion vapor are recovered, the yield of turpentine is also increased.
In a conventional system, part of the expansion vapor con-I denses in the roaster, i~ which case this part of the turpen-tine cannot be recovered.
.
.. .
Claims (6)
1. In evaporating black liquor from a contin-uously operated cellulose digester a method of recovering turpentine and heat by expansion evaporating vapors from the black liquor and bringing the vapors into indirect heat exchange with digesting liquor or digesting liquor precursor for concentrating it, a part of the vapors derived from the liquor concentration being fed to a chip steaming step.
2. The method of Claim 1, in which the vapors are brought into indirect heat exchange with a digesting liquor precursor.
3. The method of Claim 1, in which the digesting liquor or digesting liquor precursor is concentrated in at least two successive stages with expansion vapors which are derived from the respective expansion evaporation stages of black liquor expansion evaporation performed in an equal number of stages.
4. The method of Claim 2, in which additional vapor is fed to a first liquor concentration stage and that vapors derived from previous liquor concentration stages are fed to each following stage.
5. The method of Claim 1, in which the chips are first steamed under normal pressure and thereafter under slightly increased pressure.
6. The method of Claim 1, used in connection with the expansion evaporation of black liquor containing spent digesting liquor and washing solution from chlorine bleaching, in which white liquor or white liquor precursor is concentrated in such a manner that sodium chloride is crystallized from the white liquor or from the white liquor precursor, and the precipitated sodium chloride crystals are separated from the white liquor or from the white liquor precursor before it is fed to the digestion.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI1889/74A FI52127C (en) | 1974-06-19 | 1974-06-19 | SAETT ATT AOTERVINNA TERPENTIN OCH VAERME I SAMBAND MED INDUNSTNING AV SVARTLUT SOM FRAON EN KONTINUERLIGT ARBETANDE CELLULOSAKOKARE AVGAOR UNDER HOEGT TRYCK OCH HOEG TEMPERATUR |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1049713A true CA1049713A (en) | 1979-03-06 |
Family
ID=8506365
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA229,293A Expired CA1049713A (en) | 1974-06-19 | 1975-06-13 | Recovering turpentine and heat from black liquor from a continuous digestor |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1049713A (en) |
| FI (1) | FI52127C (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4421597A (en) * | 1981-12-08 | 1983-12-20 | Georgia-Pacific Corporation | Method for recovering heat in an alkaline pulp digesting process |
| US4568422A (en) * | 1981-12-08 | 1986-02-04 | Georgia-Pacific Corporation | System for recovering heat in an alkaline pulp digesting process |
| US4897157A (en) * | 1986-07-08 | 1990-01-30 | Kamyr, Inc. | Make-up liquor and black liquor evaporating processing during pulp production |
| US4909899A (en) * | 1986-09-22 | 1990-03-20 | A. Ahlstrom Corporation | Method of concentrating sludges |
| US5089087A (en) * | 1986-07-08 | 1992-02-18 | Kamyr, Inc. | Make-up liquor and black liquor evaporating process during pulp production |
| US5112441A (en) * | 1985-04-25 | 1992-05-12 | Oy Tampella Ab | Process for the recovery of heat and chemicals from spent liquor |
| WO2001049928A1 (en) * | 1999-12-29 | 2001-07-12 | Metso Chemical Pulping Oy | Method for improved turpentine recovery from modern cooking plants |
-
1974
- 1974-06-19 FI FI1889/74A patent/FI52127C/en active
-
1975
- 1975-06-13 CA CA229,293A patent/CA1049713A/en not_active Expired
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4421597A (en) * | 1981-12-08 | 1983-12-20 | Georgia-Pacific Corporation | Method for recovering heat in an alkaline pulp digesting process |
| US4568422A (en) * | 1981-12-08 | 1986-02-04 | Georgia-Pacific Corporation | System for recovering heat in an alkaline pulp digesting process |
| US5112441A (en) * | 1985-04-25 | 1992-05-12 | Oy Tampella Ab | Process for the recovery of heat and chemicals from spent liquor |
| US4897157A (en) * | 1986-07-08 | 1990-01-30 | Kamyr, Inc. | Make-up liquor and black liquor evaporating processing during pulp production |
| US5089087A (en) * | 1986-07-08 | 1992-02-18 | Kamyr, Inc. | Make-up liquor and black liquor evaporating process during pulp production |
| US4909899A (en) * | 1986-09-22 | 1990-03-20 | A. Ahlstrom Corporation | Method of concentrating sludges |
| WO2001049928A1 (en) * | 1999-12-29 | 2001-07-12 | Metso Chemical Pulping Oy | Method for improved turpentine recovery from modern cooking plants |
| US7384501B2 (en) | 1999-12-29 | 2008-06-10 | Metso Paper Pori Oy | Method for improved turpentine recovery from modern cooking plants |
Also Published As
| Publication number | Publication date |
|---|---|
| FI188974A (en) | 1975-12-20 |
| FI52127B (en) | 1977-02-28 |
| FI52127C (en) | 1978-04-17 |
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