CA1181204A - Method and system for reacting ozone with pulp - Google Patents
Method and system for reacting ozone with pulpInfo
- Publication number
- CA1181204A CA1181204A CA000403527A CA403527A CA1181204A CA 1181204 A CA1181204 A CA 1181204A CA 000403527 A CA000403527 A CA 000403527A CA 403527 A CA403527 A CA 403527A CA 1181204 A CA1181204 A CA 1181204A
- Authority
- CA
- Canada
- Prior art keywords
- pulp
- gas
- ozone
- oxygen
- vessel
- 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
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 title claims abstract description 46
- 238000000034 method Methods 0.000 title abstract description 5
- 239000007789 gas Substances 0.000 claims abstract description 71
- 239000000203 mixture Substances 0.000 claims abstract description 23
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 21
- 239000001301 oxygen Substances 0.000 claims abstract description 21
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 21
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910001882 dioxygen Inorganic materials 0.000 claims abstract description 11
- 238000000746 purification Methods 0.000 claims abstract description 10
- 230000003134 recirculating effect Effects 0.000 claims abstract description 7
- 238000011437 continuous method Methods 0.000 claims description 4
- 239000000463 material Substances 0.000 description 4
- 229920001131 Pulp (paper) Polymers 0.000 description 3
- 230000014759 maintenance of location Effects 0.000 description 2
- 208000036366 Sensation of pressure Diseases 0.000 description 1
- 241001080526 Vertica Species 0.000 description 1
- 238000004061 bleaching Methods 0.000 description 1
- 239000007844 bleaching agent Substances 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/147—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications
- D21C9/153—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications with ozone
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Paper (AREA)
- Golf Clubs (AREA)
- Stored Programmes (AREA)
- Image Generation (AREA)
Abstract
A METHOD AND SYSTEM FOR
REACTING OZONE WITH PULP
Abstract of the Disclosure Pulp is added to a pressurized vessel and, after being treated with ozone included in an ozone/oxygen gas mixture, is removed from the vessel at a treated pulp outlet located below the pulp inlet. The vessel also has a gas inlet and a gas outlet located between the pulp inlet and the treated pulp outlet with the gas outlet vertically below the gas inlet. Thus, a cocurrent flow of pulp and gas is provided in the vessel. A gas recirc-ulating system interconnects the gas inlet and the gas outlet and comprises an oxygen purification system connected to the gas outlet and an ozone generator connected to the oxygen purification system. The ozone/oxygen gas mixture from the ozone generator is fed under pressure to the vessel gas inlet.
REACTING OZONE WITH PULP
Abstract of the Disclosure Pulp is added to a pressurized vessel and, after being treated with ozone included in an ozone/oxygen gas mixture, is removed from the vessel at a treated pulp outlet located below the pulp inlet. The vessel also has a gas inlet and a gas outlet located between the pulp inlet and the treated pulp outlet with the gas outlet vertically below the gas inlet. Thus, a cocurrent flow of pulp and gas is provided in the vessel. A gas recirc-ulating system interconnects the gas inlet and the gas outlet and comprises an oxygen purification system connected to the gas outlet and an ozone generator connected to the oxygen purification system. The ozone/oxygen gas mixture from the ozone generator is fed under pressure to the vessel gas inlet.
Description
This invention relates to methods and systems for the gaseous ozone reaction with material such as wood pulp.
Mo~e particularly, this invention is a continuous method and system for continuously reacting gaseous o~one with pulp.
It is .impossible to generate pure ozone due to its chemical instability. To bleach wood pulp, the ozone must be supplied as a relatively small portion of a mixture of ozone and oxygen-carrier gas. Usually the ozone concentra-tion is limiked to 2%, the remainder ~eing oxygen. The large oxygen component of this mixture is not consumed during the bleaching process, and hence must be discharged from the reaction vessel separately from the bleached pulp.
In one me-thod of reacting gaseous ozone with pulp, a mixture of reacting gas and non-reacting gas is passed cocurrently through a bed of fluffed pulp. For a given set of conditions, such as reactor size, mass flow rate of pulp, mass ~low rate of reacting gas, retention time of the pulp in the reactor, and pressure drop of the gàs through the pulp bed, a definite corresponding depth of the pulp bed and production rate per day is given for the reactor. Certain limitations occur when trying to increase the amount of pulp which can be treated per day. One way to increase the amount of treated pulp is to increase the mass flow rate of the pulp.
To double the tonnage with the same residence time o pulp in the vessel, the bed level of the pulp must be doubled and, at the same time, the gas flow must be doubled. The result of this compacts the becl so gas does not easily flow through the pulp plug or bed. Thus, a very high differential pressure a2~
is required to pass ozone through the pulp plug. The required pressure is so high that it is not practical.
The amount of treated, fluffed pulp per day could be doubled by increasing the diameter of the reactor and keeping the level of the pulp the same so that ozone could be passed through the pulp plug. ~lowever, this would require a bulky vessel and also require larger pulp dis-charge equipment inside the reactor, which is undesirable.
With this invention, much more pulp may be treated per day, using the same vessel diameter and the same ratio of reacting gas to non-reacting gas with a larger pulp bed depth than formerly used.
This invention achieves this desired result because the mass flow rate of the reacting gas can be increased by increasing the absolute pressure of the total gas mixture prior to introducing the gas into the reactor vessel. By virtue of Boyle's Law which states that p X v = constant, an increased absolute pressure gives a proportional increase in gas density. Therefore, the same volumetric flow ra-te will yield an increased mass flow rate of react-ing gas when the pressure is increased.
Briefly described, the new system for reacting gaseous ozone with wood pulp comprises a generally vertica:L, pressurized vessel having a pulp inlet and a trea-ted pulp outlet below the pulp inlet. The vessel also has a gas inlet and a gas outlet located vertically between the pulp inlet and the treated pulp outlet, with the gas outlet vertically below the gas inlet, so that a cocurrent flow of pulp and gas occurs in the vessel. A gas recirculating system interconnects the gas inlet and the gas outlet with the recircula-ting system comprisi:ng an oxygen 8221-IM-P~
8~210~
purification system connected to the gas outlet and an ozone generator connected to the oxygen purification system and also connected to the gas inlet. The ozone generator gener-ates a mixture oE oxygen and ozone which is fed back under pressure to the vertical vessel.
The new method comprises cocurrently flowing an ozone/
oxygen gas mi~ture through the pulp bed or plug to react the ozone with the pulp. The ~xygen from the gas mixture is recovered and converted into an ozone/oxygen gas mixture.
The ozone/oxygen gas mixtuxe is conducted under pressure back to the pressurized vertical vessel. The pressure of the gas mixture is above 30 psia and preferably in the range of 30 psia to 50 psia.
The invention, as well as its many advantages, may be 15/ further understood by reference to the single drawing which / is a schematic flow diagram illustrating one preferred embodi-ment of the invention.
~ eferring more particularly to the figure, the illus-trated apparatus comprises a generally vertical or upright, pressurized reaction vessel designated generally as 10, which is closed at its upper and lower ends. The vessel 10 is constructed for operation at any pressure above atmospheric pressure. The vessel 10 is gas-tiqht to prevent yas leakage into and out o e the vessel.
The vessel 10 is provided with at least one gas inlet 12 connected to the upper end of the vessel. Fluffed pulp to be treated is fed into the vessel 10 by means of the pulp inlet 1~. The lower end of the vessel 10 is provided with 0~ ' ' a treated material discharge outlet 16. The illustrated apparatus further comprises means incorporated with the vessel 10, providing the vessel 10 with an annular, peri-pheral, gas-receiving chamber arranged to continuously upw~rdly receive a large volume of gas from a gas-material mixture in the vessel 10 separately from the material in the mixture and means for discharging gas from the upper end of the gas-receiving chamber. This gas-receiving cham-ber is open to the vessel interior 10 substantially spaced intermediate the upper and lower ends thereof and at a location substan ially spaced, longitudinally of the vessel 10 between the connecting inlets 12,14 and the connection of the materials discharge outlet 16.
The vessel 10 includes an upper portion 18 and a there-below adjoined lower portion 20. The upper portion 18 of thevessel interior is throughout its length formed of horizontal cross-section or cross-sectional area substantially less than that of the communicating lower portion 20 of the vessel interior. A gas outlet 22 is connected to the upper part of the lower portion 20 of the vessel. The gas inlet 12 and the gas outlet 22 are located vertically between the pulp inlet 14 and the treated pulp outlet 16, with the gas outlet 22 being vertically below the gas inlet. Thus, a cocurrent flow o pulp and gas occurs in the vessel with the rate of flow of the gas being greater than the rate of flow of the pulp .
In accordance with the invention, a gas reci~cula~ing system interconnects the gas inlet 12 and the gas outlet 22.
The gas recirculating system comprises an oxygen purifica-tion system 24 connected to the gas outlet 22 by gas conduit 26, and an ozone generator 28 connected to the oxygen puri-fication system 24 by means of a gas conduit 30 which has a compressor 36. Compressor 36 makes up for pressure drops in vessel 10 and the gas recirculating system. The gas mixture is compressed in compressor 36 while simultaneously cooled. A water-ring compressor such as the Nash Pump is one example of a suitable compressor. The oxygen purifica-tion system 24 makes the oxygen from the vessel 10 reusable.It might include, for example, a scrubber to remove pulp or . . .
dust in the gas, a catalytic converter to destroy organic compounds, a cooler to remove most of the water vapor, and a dessicant to bring the moisture to a very low level. The ozone generator may be any suitable ozone generator such as, for example, a Lowther Plate-Type generator. The ozone generator is connected to the gas inlet 12 by gas conduit 34.
In commercial ozone-generating systems, the gas mixture is produced at around 15 to 25 psia and consists of about 98% oxygen and 2% ozone by weight. For a given pressure drop of say 5 psi and reactor diameter of say 10 feet that we feel are desirable, this results in a bed depth of around 5 feet. For the resulting retention time in the reactor vessel 10, this results in a pulp rate of about 250 tons per day. Using this invention, if the gas mixture absolute pres-sure is doubled (fxom 25 psla to 50 psia), 75% of the volu-~etric flow rate of gas provides 50% more mass flow rate of ozone, so that a 50% increase in the mass flow rate of the ~81~4 8221-IM-PA
pulp or a pulp rate of around 375 tons per day is obtained without increasing the reactor diameter and pressure drop.
Only an increase in bed depth is necessary and possible because of the decreased volumetric gas flow.
Mo~e particularly, this invention is a continuous method and system for continuously reacting gaseous o~one with pulp.
It is .impossible to generate pure ozone due to its chemical instability. To bleach wood pulp, the ozone must be supplied as a relatively small portion of a mixture of ozone and oxygen-carrier gas. Usually the ozone concentra-tion is limiked to 2%, the remainder ~eing oxygen. The large oxygen component of this mixture is not consumed during the bleaching process, and hence must be discharged from the reaction vessel separately from the bleached pulp.
In one me-thod of reacting gaseous ozone with pulp, a mixture of reacting gas and non-reacting gas is passed cocurrently through a bed of fluffed pulp. For a given set of conditions, such as reactor size, mass flow rate of pulp, mass ~low rate of reacting gas, retention time of the pulp in the reactor, and pressure drop of the gàs through the pulp bed, a definite corresponding depth of the pulp bed and production rate per day is given for the reactor. Certain limitations occur when trying to increase the amount of pulp which can be treated per day. One way to increase the amount of treated pulp is to increase the mass flow rate of the pulp.
To double the tonnage with the same residence time o pulp in the vessel, the bed level of the pulp must be doubled and, at the same time, the gas flow must be doubled. The result of this compacts the becl so gas does not easily flow through the pulp plug or bed. Thus, a very high differential pressure a2~
is required to pass ozone through the pulp plug. The required pressure is so high that it is not practical.
The amount of treated, fluffed pulp per day could be doubled by increasing the diameter of the reactor and keeping the level of the pulp the same so that ozone could be passed through the pulp plug. ~lowever, this would require a bulky vessel and also require larger pulp dis-charge equipment inside the reactor, which is undesirable.
With this invention, much more pulp may be treated per day, using the same vessel diameter and the same ratio of reacting gas to non-reacting gas with a larger pulp bed depth than formerly used.
This invention achieves this desired result because the mass flow rate of the reacting gas can be increased by increasing the absolute pressure of the total gas mixture prior to introducing the gas into the reactor vessel. By virtue of Boyle's Law which states that p X v = constant, an increased absolute pressure gives a proportional increase in gas density. Therefore, the same volumetric flow ra-te will yield an increased mass flow rate of react-ing gas when the pressure is increased.
Briefly described, the new system for reacting gaseous ozone with wood pulp comprises a generally vertica:L, pressurized vessel having a pulp inlet and a trea-ted pulp outlet below the pulp inlet. The vessel also has a gas inlet and a gas outlet located vertically between the pulp inlet and the treated pulp outlet, with the gas outlet vertically below the gas inlet, so that a cocurrent flow of pulp and gas occurs in the vessel. A gas recirculating system interconnects the gas inlet and the gas outlet with the recircula-ting system comprisi:ng an oxygen 8221-IM-P~
8~210~
purification system connected to the gas outlet and an ozone generator connected to the oxygen purification system and also connected to the gas inlet. The ozone generator gener-ates a mixture oE oxygen and ozone which is fed back under pressure to the vertical vessel.
The new method comprises cocurrently flowing an ozone/
oxygen gas mi~ture through the pulp bed or plug to react the ozone with the pulp. The ~xygen from the gas mixture is recovered and converted into an ozone/oxygen gas mixture.
The ozone/oxygen gas mixtuxe is conducted under pressure back to the pressurized vertical vessel. The pressure of the gas mixture is above 30 psia and preferably in the range of 30 psia to 50 psia.
The invention, as well as its many advantages, may be 15/ further understood by reference to the single drawing which / is a schematic flow diagram illustrating one preferred embodi-ment of the invention.
~ eferring more particularly to the figure, the illus-trated apparatus comprises a generally vertical or upright, pressurized reaction vessel designated generally as 10, which is closed at its upper and lower ends. The vessel 10 is constructed for operation at any pressure above atmospheric pressure. The vessel 10 is gas-tiqht to prevent yas leakage into and out o e the vessel.
The vessel 10 is provided with at least one gas inlet 12 connected to the upper end of the vessel. Fluffed pulp to be treated is fed into the vessel 10 by means of the pulp inlet 1~. The lower end of the vessel 10 is provided with 0~ ' ' a treated material discharge outlet 16. The illustrated apparatus further comprises means incorporated with the vessel 10, providing the vessel 10 with an annular, peri-pheral, gas-receiving chamber arranged to continuously upw~rdly receive a large volume of gas from a gas-material mixture in the vessel 10 separately from the material in the mixture and means for discharging gas from the upper end of the gas-receiving chamber. This gas-receiving cham-ber is open to the vessel interior 10 substantially spaced intermediate the upper and lower ends thereof and at a location substan ially spaced, longitudinally of the vessel 10 between the connecting inlets 12,14 and the connection of the materials discharge outlet 16.
The vessel 10 includes an upper portion 18 and a there-below adjoined lower portion 20. The upper portion 18 of thevessel interior is throughout its length formed of horizontal cross-section or cross-sectional area substantially less than that of the communicating lower portion 20 of the vessel interior. A gas outlet 22 is connected to the upper part of the lower portion 20 of the vessel. The gas inlet 12 and the gas outlet 22 are located vertically between the pulp inlet 14 and the treated pulp outlet 16, with the gas outlet 22 being vertically below the gas inlet. Thus, a cocurrent flow o pulp and gas occurs in the vessel with the rate of flow of the gas being greater than the rate of flow of the pulp .
In accordance with the invention, a gas reci~cula~ing system interconnects the gas inlet 12 and the gas outlet 22.
The gas recirculating system comprises an oxygen purifica-tion system 24 connected to the gas outlet 22 by gas conduit 26, and an ozone generator 28 connected to the oxygen puri-fication system 24 by means of a gas conduit 30 which has a compressor 36. Compressor 36 makes up for pressure drops in vessel 10 and the gas recirculating system. The gas mixture is compressed in compressor 36 while simultaneously cooled. A water-ring compressor such as the Nash Pump is one example of a suitable compressor. The oxygen purifica-tion system 24 makes the oxygen from the vessel 10 reusable.It might include, for example, a scrubber to remove pulp or . . .
dust in the gas, a catalytic converter to destroy organic compounds, a cooler to remove most of the water vapor, and a dessicant to bring the moisture to a very low level. The ozone generator may be any suitable ozone generator such as, for example, a Lowther Plate-Type generator. The ozone generator is connected to the gas inlet 12 by gas conduit 34.
In commercial ozone-generating systems, the gas mixture is produced at around 15 to 25 psia and consists of about 98% oxygen and 2% ozone by weight. For a given pressure drop of say 5 psi and reactor diameter of say 10 feet that we feel are desirable, this results in a bed depth of around 5 feet. For the resulting retention time in the reactor vessel 10, this results in a pulp rate of about 250 tons per day. Using this invention, if the gas mixture absolute pres-sure is doubled (fxom 25 psla to 50 psia), 75% of the volu-~etric flow rate of gas provides 50% more mass flow rate of ozone, so that a 50% increase in the mass flow rate of the ~81~4 8221-IM-PA
pulp or a pulp rate of around 375 tons per day is obtained without increasing the reactor diameter and pressure drop.
Only an increase in bed depth is necessary and possible because of the decreased volumetric gas flow.
Claims (5)
1. A system for reacting gaseous ozone with pulp comprising: a generally vertical vessel, said vessel having a pulp inlet, and a treated pulp outlet below the pulp inlet, said vessel also having a gas inlet and a gas outlet vertically between the pulp inlet and the treated pulp outlet with the gas outlet vertically below the gas inlet whereby a cocurrent flow of pulp and gas occurs in the vessel; and a gas recirculating system interconnecting the gas inlet and the gas outlet and comprising an oxygen purification system for purifying oxygen from the gas out-let and an ozone generator for generating ozone from the oxygen received from the oxygen purification system, said recirculating system also having means for conducting the ozone/oxygen mixture from the ozone generator to the gas inlet.
2. A system in accordance with claim 1 wherein the means for conducting the ozone/oxygen mixture from the purification system to the ozone generator includes a compressor.
3. A continuous method of reacting gaseous ozone with pulp comprising the steps of: feeding fluffed pulp to a pressurized vertical vessel; forming a pulp plug in the vessel and flowing the pulp plug through the vessel at a predetermined flow rate; cocurrently flowing an ozone/
oxygen gas mixture through the plug to react the ozone in the gas mixture with the pulp in the pulp plug so that only oxygen remains from the ozone/oxygen gas mixture;
purifying said oxygen; converting said oxygen into an ozone/oxygen gas mixture; and conducting the ozone/oxygen gas under pressure back to the pressurized vertical vessel.
oxygen gas mixture through the plug to react the ozone in the gas mixture with the pulp in the pulp plug so that only oxygen remains from the ozone/oxygen gas mixture;
purifying said oxygen; converting said oxygen into an ozone/oxygen gas mixture; and conducting the ozone/oxygen gas under pressure back to the pressurized vertical vessel.
4. A continuous method of reacting gaseous ozone with pulp in accordance with claim 3 wherein the ozone/oxygen gas mixture pressure is above 30 psia.
5. A continuous method of reacting gaseous ozone with pulp in accordance with claim 4 wherein the ozone/oxygen gas mixture pressure ranges from 30 psia to 50 psia.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US274,434 | 1981-06-17 | ||
| US06/274,434 US4394533A (en) | 1980-06-25 | 1981-06-17 | Air-cooled cables with terminals and method of producing same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1181204A true CA1181204A (en) | 1985-01-22 |
Family
ID=23048182
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000403527A Expired CA1181204A (en) | 1981-06-17 | 1982-05-21 | Method and system for reacting ozone with pulp |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA1181204A (en) |
| FI (1) | FI822168L (en) |
| NO (1) | NO821999L (en) |
| SE (1) | SE8203344L (en) |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5164043A (en) * | 1990-05-17 | 1992-11-17 | Union Camp Patent Holding, Inc. | Environmentally improved process for bleaching lignocellulosic materials with ozone |
| US5164044A (en) * | 1990-05-17 | 1992-11-17 | Union Camp Patent Holding, Inc. | Environmentally improved process for bleaching lignocellulosic materials with ozone |
| US5174861A (en) * | 1990-10-26 | 1992-12-29 | Union Camp Patent Holdings, Inc. | Method of bleaching high consistency pulp with ozone |
| US5181989A (en) * | 1990-10-26 | 1993-01-26 | Union Camp Patent Holdings, Inc. | Reactor for bleaching high consistency pulp with ozone |
| US5188708A (en) * | 1989-02-15 | 1993-02-23 | Union Camp Patent Holding, Inc. | Process for high consistency oxygen delignification followed by ozone relignification |
| US5211811A (en) * | 1989-02-15 | 1993-05-18 | Union Camp Patent Holding, Inc. | Process for high consistency oxygen delignification of alkaline treated pulp followed by ozone delignification |
| US5409570A (en) * | 1989-02-15 | 1995-04-25 | Union Camp Patent Holding, Inc. | Process for ozone bleaching of oxygen delignified pulp while conveying the pulp through a reaction zone |
| US5441603A (en) * | 1990-05-17 | 1995-08-15 | Union Camp Patent Holding, Inc. | Method for chelation of pulp prior to ozone delignification |
| US5451296A (en) * | 1991-05-24 | 1995-09-19 | Union Camp Patent Holding, Inc. | Two stage pulp bleaching reactor |
| US5472572A (en) * | 1990-10-26 | 1995-12-05 | Union Camp Patent Holding, Inc. | Reactor for bleaching high consistency pulp with ozone |
| US5520783A (en) * | 1990-10-26 | 1996-05-28 | Union Camp Patent Holding, Inc. | Apparatus for bleaching high consistency pulp with ozone |
| US5554259A (en) | 1993-10-01 | 1996-09-10 | Union Camp Patent Holdings, Inc. | Reduction of salt scale precipitation by control of process stream Ph and salt concentration |
-
1982
- 1982-05-21 CA CA000403527A patent/CA1181204A/en not_active Expired
- 1982-05-28 SE SE8203344A patent/SE8203344L/en not_active Application Discontinuation
- 1982-06-16 NO NO821999A patent/NO821999L/en unknown
- 1982-06-16 FI FI822168A patent/FI822168L/en not_active Application Discontinuation
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5409570A (en) * | 1989-02-15 | 1995-04-25 | Union Camp Patent Holding, Inc. | Process for ozone bleaching of oxygen delignified pulp while conveying the pulp through a reaction zone |
| US5188708A (en) * | 1989-02-15 | 1993-02-23 | Union Camp Patent Holding, Inc. | Process for high consistency oxygen delignification followed by ozone relignification |
| US5211811A (en) * | 1989-02-15 | 1993-05-18 | Union Camp Patent Holding, Inc. | Process for high consistency oxygen delignification of alkaline treated pulp followed by ozone delignification |
| US5164044A (en) * | 1990-05-17 | 1992-11-17 | Union Camp Patent Holding, Inc. | Environmentally improved process for bleaching lignocellulosic materials with ozone |
| US5441603A (en) * | 1990-05-17 | 1995-08-15 | Union Camp Patent Holding, Inc. | Method for chelation of pulp prior to ozone delignification |
| US5164043A (en) * | 1990-05-17 | 1992-11-17 | Union Camp Patent Holding, Inc. | Environmentally improved process for bleaching lignocellulosic materials with ozone |
| US5296099A (en) * | 1990-05-17 | 1994-03-22 | Union Camp Holding, Inc. | Environmentally improved process for bleaching lignocellulosic materials with oxygen, ozone and chlorine dioxide |
| US5181989A (en) * | 1990-10-26 | 1993-01-26 | Union Camp Patent Holdings, Inc. | Reactor for bleaching high consistency pulp with ozone |
| US5174861A (en) * | 1990-10-26 | 1992-12-29 | Union Camp Patent Holdings, Inc. | Method of bleaching high consistency pulp with ozone |
| US5472572A (en) * | 1990-10-26 | 1995-12-05 | Union Camp Patent Holding, Inc. | Reactor for bleaching high consistency pulp with ozone |
| US5520783A (en) * | 1990-10-26 | 1996-05-28 | Union Camp Patent Holding, Inc. | Apparatus for bleaching high consistency pulp with ozone |
| US5863389A (en) * | 1990-10-26 | 1999-01-26 | Union Camp Patent Holding, Inc. | Pulp bleaching reactor for dispersing high consistency pulp into a gaseous bleaching agent containing ozone |
| US5451296A (en) * | 1991-05-24 | 1995-09-19 | Union Camp Patent Holding, Inc. | Two stage pulp bleaching reactor |
| US5554259A (en) | 1993-10-01 | 1996-09-10 | Union Camp Patent Holdings, Inc. | Reduction of salt scale precipitation by control of process stream Ph and salt concentration |
| US5693184A (en) * | 1993-10-01 | 1997-12-02 | Union Camp Patent Holding, Inc. | Reduction of salt scale precipitation by control of process stream pH and salt concentration |
Also Published As
| Publication number | Publication date |
|---|---|
| SE8203344L (en) | 1982-12-18 |
| NO821999L (en) | 1982-12-20 |
| FI822168A0 (en) | 1982-06-16 |
| FI822168L (en) | 1982-12-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |