US20030116290A1 - Continuous process for controlled evaporation of black liquor - Google Patents

Continuous process for controlled evaporation of black liquor Download PDF

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Publication number
US20030116290A1
US20030116290A1 US10/028,025 US2802501A US2003116290A1 US 20030116290 A1 US20030116290 A1 US 20030116290A1 US 2802501 A US2802501 A US 2802501A US 2003116290 A1 US2003116290 A1 US 2003116290A1
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black liquor
preconcentrated
pressure
evaporation
weak black
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Robert Davidson
Danny Anderson
Richard Gerth
David Holm
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3M Innovative Properties Co
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3M Innovative Properties Co
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Assigned to 3M INNOVATIVE PROPERTIES COMPANY reassignment 3M INNOVATIVE PROPERTIES COMPANY ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ANDERSON, DANNY B., DAVIDSON, ROBERT S., GERTH, RICHARD A., HOLM, DAVID R.
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    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21CPRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C11/00Regeneration of pulp liquors or effluent waste waters
    • D21C11/10Concentrating spent liquor by evaporation

Definitions

  • the present invention relates generally to continuous pulp production. More particularly, the invention relates to a method for evaporating weak black liquor to form strong black liquor.
  • weak black liquor spent pulping liquor
  • Weak black liquor typically contains 15 wt % dissolved and suspended solids of which about 80% are organic compounds and the remainder are inorganic compounds.
  • the weak black liquor is separated from the pulp at a certain point in the process of pulp production.
  • the weak black liquor is then subjected to evaporation to remove water.
  • the weak black liquor, after it is concentrated, is then called “strong black liquor.”
  • the strong black liquor is then passed to a recovery boiler where the strong black liquor is combusted to recover inorganics, such as sulfur and sodium, for reuse in the pulping process.
  • the steam that is produced by the combustion of the strong black liquor is used for heating in the pulping process.
  • the solids content in the strong black liquor must lie in a desired range to ensure proper burning in the recovery boiler. If too much water is evaporated, viscous strong black liquor may plug the spray nozzles or simply spray improperly, possibly extinguishing the burner flame. Conversely, if too little water is evaporated from the weak black liquor, the organics content will be too low to sustain a flame. Either case is dangerous, because the unburned strong black liquor would then fall into a pool of molten inorganic chemicals, which lies at the bottom of the recovery boiler, possibly causing an explosion. System interlocks are relied upon to shut off the flow of strong black liquor to the burner nozzles if the flame goes out.
  • the present inventive process provides a controlled method for evaporating weak black liquor to form strong black liquor.
  • the method offers fast and precise control of viscosity of the strong black liquor.
  • the control scheme allows for regulation of the concentration of the outgoing product to tight tolerances by manipulating the system pressure and the temperature of the incoming black liquor. It allows for good control over the product percent solids, and the product viscosity. Precisely controlling the viscosity and solids content of the strong black liquor sent to the recovery boiler would not only improve safety, but would also allow optimization of the operation of the recovery boiler, with respect to both chemical recovery capacity and energy efficiency.
  • the inventive process is a process for concentrating weak black liquor to form strong black liquor, said process comprising: a) preconcentrating said weak black liquor; b) heating said preconcentrated weak black liquor in a heating zone under sufficient pressure to prevent said preconcentrated weak black liquor from boiling in said heating zone; c) passing said preconcentrated weak black liquor having a vapor pressure and having at least one volatile component, into an evaporation zone through one or more orifices; d) applying pressure in said evaporation zone that is lower than the vapor pressure of said preconcentrated weak black liquor as it is passed into said evaporation zone, which allows for flash evaporation of at least a portion of said at least one volatile component of said preconcentrated weak black liquor from said preconcentrated weak black liquor to form strong black liquor; e) adjusting temperature in said heating zone, pressure in said heating zone and pressure in said evaporation zone to allow for evaporation of an amount of said at least one volatile component from said preconcentrated weak black liquor to form said strong black liquor; and
  • FIG. 1 is a process flow diagram of an embodiment of the present inventive method.
  • FIG. 2 is a graph showing evaporator response time for sugar solution, with the normalized change in % solids versus the time, in minutes, for such a change in pressure (two changes) and temperature (two changes).
  • FIG. 1 An embodiment of the present invention is illustrated in FIG. 1 by a process flow diagram.
  • weak black liquor from the wood pulping and washing steps of a pulp production process is preconcentrated in a preconcentrator 12 .
  • the bulk of the water, aqueous media or solvent media in the weak black liquor is removed in this step.
  • the preconcentrated weak black liquor is then pumped, using a pump 14 , to a heating zone 16 where it is heated.
  • a temperature sensor 18 monitors or senses the temperature of the heating zone 16 .
  • the preconcentrated weak black liquor is kept under sufficient temperature and pressure in the heating zone 16 to keep the preconcentrated weak black liquor from boiling there.
  • a pressure sensor 20 and another temperature sensor 22 in the system prior to an evaporation zone (a “zone” is a chamber, enclosed area, etc.) 24 , which are used to sense the pressure and the temperature of the preconcentrated weak black liquor just prior to the preconcentrated weak black liquor entering the evaporation zone 24 .
  • the preconcentrated weak black liquor is then passed into the evaporation zone 24 through an inlet 26 and a die 28 comprising one or more orifices.
  • the die 28 is constructed such that the pressure drop through the die should prevent the preconcentrated weak black liquor from boiling until it has nearly entered, or has actually entered the evaporation zone.
  • pressure is controlled in the evaporation zone 24 such that it is lower than the vapor pressure of the heated preconcentrated weak black liquor as it enters the evaporation zone 24 .
  • the strong black liquor is cooled as it passes through the evaporation zone 24 and then goes through an outlet 30 .
  • a vapor exit port 34 is attached to the evaporation zone 24 where the vapor that was evaporated out of the strong black liquor in the evaporation zone 24 is removed from the evaporation zone 24 .
  • Another pressure sensor 36 is located outside of the vapor exit port 34 or could be somewhere connected to the evaporation zone 24 itself, and is used to sense the pressure in the evaporation chamber 24 or just outside of it. In order for the vapor to exit the evaporation zone 24 the pressure needs to be lower outside of the evaporation zone 24 than inside.
  • the lower pressure outside of the evaporation zone 24 may be provided by a vacuum system 40 that is connected to the system via a condenser 38 where most of the vapor is condensed for removal. Alternatively, vapors may pass directly to the pressure control or the vacuum system.
  • the strong black liquor is collected in a collection vessel 42 . It is then pumped out of the system by a pump 44 .
  • a conditions sensor 46 senses, measure or infers such things as viscosity, pressure, concentration and heating value of the strong black liquor and is found at or near the exit for the strong black liquor or is attached to the collection vessel. These measurements or inferences can be used in controlling the operation of the system.
  • the preconcentrating step may be performed using a preconcentrator 12 .
  • Apparatuses that may be used as preconcentrators include, for example, multi-effect evaporators.
  • Preconcentrating means removing a portion of at least one volatile component in a solution or liquid medium prior to the first step of a process.
  • the volatile component of the weak black liquor that is removed or evaporated is mostly or all water. Other ingredients in the weak black liquor may also be evaporated, although that is not most desirable.
  • the heating step of the present inventive method is performed in a heating zone 16 .
  • the heating is preferably done using a heat exchanger.
  • the heating step may be performed, however, by any suitable heating means or device.
  • Some examples of other heating means include, but are not limited to, direct steam injection and microwaves.
  • the preconcentrated weak black liquor is heated to a temperature in the heating zone that is suitable so that the preconcentrated weak black liquor will have a temperature that is above the boiling point of the preconcentrated weak black liquor at the pressure in the evaporation zone.
  • the pressure in the heating zone is maintained so that the preconcentrated weak black liquor is not allowed to boil.
  • the range of pressures depends upon the composition of the preconcentrated weak black liquor and the temperature of the heating zone and of the preconcentrated weak black liquor.
  • the preconcentrated weak black liquor is passed through an inlet or conduit and through a die 28 or nozzle or some sort of orifice into the evaporation zone itself.
  • the die or nozzle may be of any suitable shape and configuration that allow the heated preconcentrated weak black liquor to pass through into the evaporation zone 24 .
  • the shape and/or number of orifice(s) through which it passes may allow for increase in the surface area of the preconcentrated weak black liquor that is exposed in the evaporation zone as it is passed through the zone.
  • the preconcentrated weak black liquor is passed through into the evaporation zone 24 and is flash evaporated.
  • the die 28 which is a device having a specific shape or design that it imparts to such material that is passed through it, is of a suitable shape or configuration that allows the preconcentrated weak black liquor to pass through the evaporation zone 24 and be flash evaporated to form strong black liquor.
  • Some die designs will have the added property that the preconcentrated weak black liquor will pass through the evaporation zone 24 and be flash evaporated to form strong black liquor without substantially contacting the inner surface or surfaces 32 of the evaporation zone 24 . In some operations this is desirable.
  • An exemplary die has a plurality of orifices or holes that allow the preconcentrated weak black liquor to form strands or streams (that may be discontinuous) as the preconcentrated weak black liquor passes through the evaporation zone 24 .
  • Another possibility is for the die 28 to have orifices that are slits and allow for sheets or curtains (that may be discontinuous) of heated preconcentrated weak black liquor to travel or fall into the evaporation chamber 24 .
  • These exemplary designs of the die 28 allow more surface area of preconcentrated weak black liquor to be exposed in the evaporation zone 24 , which allows for more efficient evaporation.
  • Other configurations of the die and its orifice or orifices are also contemplated for this invention.
  • the at least one volatile component (volatile component being volatile at the temperature at which the preconcentrated weak black liquor enters the evaporation zone and at the pressure in the evaporation zone) that is evaporated from the preconcentrated weak black liquor to form the strong black liquor is mostly, if not all, water. Other ingredients of the preconcentrated weak black liquor may be evaporated, although that is not most desirable.
  • the evaporation step relies on the mechanism wherein the energy absorbed by the preconcentrated weak black liquor during the heating step is preserved by maintaining a back pressure on the preconcentrated weak black liquor to prevent vaporization of the preconcentrated weak black liquor in the inlet 26 to the evaporation zone 24 , and is subsequently released in the evaporation zone causing evaporation.
  • the number and size of the orifices in the die 28 affect the back pressure that is maintained upstream. The back pressure must be sufficient to keep the preconcentrated weak black liquor from boiling before it enters the evaporation zone 24 .
  • a multi-orifice die may be preferred, particularly because the weak black liquor is to be concentrated or evaporated in a single pass through the evaporation zone. Selection of the number and size of the orifices is used to achieve the desired pressure to prevent boiling of the preconcentrated weak black liquor prior to entering the evaporation zone.
  • the pressure in the evaporation zone 24 is controlled so that when the preconcentrated weak black liquor enters the evaporation zone 24 it flash evaporates.
  • the desired level of pressure necessary in the process may be calculated using, for example, the calculations set forth in Reid et al., The Properties of Gases and Liquids, McGraw-Hill Book Co., 4 th ed., Chapters 7 and 8, and Appendix A.
  • the strong black liquor will generally have a percent solids of about 45-50 wt % solids before it is fed to the recovery boiler.
  • the pressure and/or temperature of the inventive process are periodically or continuously controlled and manually or automatically controlled. This is done using a plurality of temperature and pressure sensors, as described above.
  • a conditions sensor may be used to monitor the conditions or properties of the remaining (or post-evaporation) strong black liquor.
  • the sensors may be part of a control system(s) that can regulate the pressure and temperature of the pre-evaporation black liquor, evaporation zone, etc.
  • one or more of the variables in the inventive process are regulated by automatic control systems, the set points having been manually supplied by an operator.
  • one or more of the closed-loop systems that regulate temperature and pressure will receive set points from another control system, based on directly measured or inferred properties of the post-evaporation strong black liquor.
  • the entire inventive process will be controlled by an automatic control system, based on measurements of temperature and/or pressure, and on properties of the post-evaporation strong black liquor. The operator will specify a desired property (such as percent solids content) of the post-evaporation strong black liquor, and the control system will automatically regulate process variables in such a way as to achieve the desired property.
  • the control system may comprise a single multivariable controller, or several independent single-loop controllers, or a combination of controller types.
  • the concentrated black liquor is collected in a collection vessel 42 .
  • a pump may be mounted at, in, or after the collection vessel.
  • a pump should be selected to be of a type that can remove strong black liquor from the collection vessel and pass it at a higher pressure into an ultimate collection vessel of some type, or it could be passed to the recovery boiler (in pulp production process) from the collection vessel. This may be done continuously or periodically.
  • sucrose solutions were used in place of black liquor. Black liquor is difficult to obtain for laboratory studies unless one is closely associated with a pulp manufacturing plant. It is expected that the sucrose solutions mimicked the behavior of black liquor in the inventive process. In the examples, all parts, ratios and percentages are by weight unless otherwise indicated. The following test method was used to characterize the compositions in the following examples.
  • Dried solids of sucrose solutions were determined from measuring the refractive index of the material and using that measurement to calculate the solids in weight percent.
  • the refractive index of each sample was measured with a Leica Mark II Abbe Refractometer (available from Leica Microsystems, Inc., Depen, N.Y.) with the temperature of the water bath maintained at 25° C.
  • the concentration of each sucrose solution was calculated from the measured refractive index of the solution and a correlation between concentration and refractive index.
  • the correlation between concentration and refractive index was determined from data in “Properties of Sucrose Solutions,” CRC Handbook of Chemistry and Physics, 53rd Edition, page D-128, The Chemical Rubber Co., Cleveland (1972).
  • the material to be concentrated was placed in a pressurized, jacketed feed vessel kept at 240 kPa (20 psig) and 40° C. This material was continuously fed to the evaporation zone using the pressure in the feed tank and a valve to adjust the flow of liquid.
  • the feed was heated by passing through a custom-made heat exchanger consisting of a jacketed tube inside an outer tube. The feed passed through the inner tube that had a length of about 610 mm (24 in) and an outer diameter of about 6.3 mm (0.25 in). Temperature controlled water passed through the outer tube that had a diameter of about 25 mm (1 in).
  • the material next passed through a custom-made die containing a single hole or orifice, about 1.09 mm (0.043 in) in diameter, before entering the evaporation zone.
  • the evaporation zone consisted of a vertical portion comprising a CLAISENTM adapter, available as Part No. 5135 from Ace Glass Inc., Vineland, N.J.
  • a side arm came off the vertical portion and sloped upward to a vertical 10/30 joint, which was connected to a pressure transducer (Model number 1151AP5E333B1, available from Rosemount, Inc., Chanhassen, Minn.).
  • Another side arm sloping off the side arm described immediately above had a male 24/40 fitting that was connected to a water aspirator vacuum system (custom-made).
  • the concentrated material was continuously removed from the evaporation zone using an air-driven pump (Model FH432 from Viking Pump, Inc., Cedar Falls, Iowa).
  • This Example illustrates the response time for a pressure only change.
  • This Example illustrates the response time for a temperature change only.
  • Solids wt % was determined for all samples. Temperature, refractive index and calculated solids wt % are shown in Table 2 with elapsed time. TABLE 2 Elapsed Time Temperature Refractive Index Sample min ° C. at 25° C.
  • FIG. 2 shows the normalized solids % changes as they relate to changes in the pressure or temperature for Examples 1 and 2 from the start of each change in condition.
  • the response to a change in pressure was much faster than the response to a change in temperature.

Abstract

Described is a process for concentrating weak black liquor to form strong black liquor, said process comprising: a) preconcentrating said weak black liquor; b) heating said preconcentrated weak black liquor in a heating zone under sufficient pressure to prevent said preconcentrated weak black liquor from boiling in said heating zone; c) passing said preconcentrated weak black liquor, having at least one volatile component, into an evaporation zone through one or more orifices; d) applying pressure in said evaporation zone that is lower than the vapor pressure of said preconcentrated weak black liquor as it is passed into said evaporation zone, which allows for flash evaporation of at least a portion of said at least one volatile component of said preconcentrated weak black liquor from said preconcentrated weak black liquor to form strong black liquor; e) adjusting heat in said heating zone., pressure in said heating zone and pressure in said evaporation zone to allow for evaporation of an amount of said at least one volatile component from said preconcentrated weak black liquor to form said strong black liquor; and f) collecting said strong black liquor from said evaporation zone.

Description

    FIELD OF THE INVENTION
  • The present invention relates generally to continuous pulp production. More particularly, the invention relates to a method for evaporating weak black liquor to form strong black liquor. [0001]
  • BACKGROUND OF THE INVENTION
  • In the pulping process, it is found that by separating spent pulping liquor (known as “weak black liquor”) from the fibrous plant material, the purity of the pulp is improved. Weak black liquor typically contains 15 wt % dissolved and suspended solids of which about 80% are organic compounds and the remainder are inorganic compounds. The weak black liquor is separated from the pulp at a certain point in the process of pulp production. The weak black liquor is then subjected to evaporation to remove water. The weak black liquor, after it is concentrated, is then called “strong black liquor.” The strong black liquor is then passed to a recovery boiler where the strong black liquor is combusted to recover inorganics, such as sulfur and sodium, for reuse in the pulping process. The steam that is produced by the combustion of the strong black liquor is used for heating in the pulping process. [0002]
  • The solids content in the strong black liquor must lie in a desired range to ensure proper burning in the recovery boiler. If too much water is evaporated, viscous strong black liquor may plug the spray nozzles or simply spray improperly, possibly extinguishing the burner flame. Conversely, if too little water is evaporated from the weak black liquor, the organics content will be too low to sustain a flame. Either case is dangerous, because the unburned strong black liquor would then fall into a pool of molten inorganic chemicals, which lies at the bottom of the recovery boiler, possibly causing an explosion. System interlocks are relied upon to shut off the flow of strong black liquor to the burner nozzles if the flame goes out. [0003]
  • Processes for the evaporation of weak black liquor to form strong black liquor are known in the art, such as direct contact evaporators, indirectly-heated concentrators, and multi-effect evaporators. However, the need still exists for a process that can control the concentration of strong black liquor reliably, consistently and precisely. [0004]
  • SUMMARY OF THE INVENTION
  • The present inventive process provides a controlled method for evaporating weak black liquor to form strong black liquor. Advantageously, the method offers fast and precise control of viscosity of the strong black liquor. The control scheme allows for regulation of the concentration of the outgoing product to tight tolerances by manipulating the system pressure and the temperature of the incoming black liquor. It allows for good control over the product percent solids, and the product viscosity. Precisely controlling the viscosity and solids content of the strong black liquor sent to the recovery boiler would not only improve safety, but would also allow optimization of the operation of the recovery boiler, with respect to both chemical recovery capacity and energy efficiency. [0005]
  • The inventive process is a process for concentrating weak black liquor to form strong black liquor, said process comprising: a) preconcentrating said weak black liquor; b) heating said preconcentrated weak black liquor in a heating zone under sufficient pressure to prevent said preconcentrated weak black liquor from boiling in said heating zone; c) passing said preconcentrated weak black liquor having a vapor pressure and having at least one volatile component, into an evaporation zone through one or more orifices; d) applying pressure in said evaporation zone that is lower than the vapor pressure of said preconcentrated weak black liquor as it is passed into said evaporation zone, which allows for flash evaporation of at least a portion of said at least one volatile component of said preconcentrated weak black liquor from said preconcentrated weak black liquor to form strong black liquor; e) adjusting temperature in said heating zone, pressure in said heating zone and pressure in said evaporation zone to allow for evaporation of an amount of said at least one volatile component from said preconcentrated weak black liquor to form said strong black liquor; and f) collecting said strong black liquor from said evaporation zone. [0006]
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 is a process flow diagram of an embodiment of the present inventive method; and [0007]
  • FIG. 2 is a graph showing evaporator response time for sugar solution, with the normalized change in % solids versus the time, in minutes, for such a change in pressure (two changes) and temperature (two changes).[0008]
  • DETAILED DESCRIPTION OF THE INVENTION
  • An embodiment of the present invention is illustrated in FIG. 1 by a process flow diagram. In this embodiment, weak black liquor from the wood pulping and washing steps of a pulp production process is preconcentrated in a [0009] preconcentrator 12. The bulk of the water, aqueous media or solvent media in the weak black liquor is removed in this step.
  • The preconcentrated weak black liquor is then pumped, using a [0010] pump 14, to a heating zone 16 where it is heated. A temperature sensor 18 monitors or senses the temperature of the heating zone 16. The preconcentrated weak black liquor is kept under sufficient temperature and pressure in the heating zone 16 to keep the preconcentrated weak black liquor from boiling there.
  • There is a [0011] pressure sensor 20 and another temperature sensor 22 in the system prior to an evaporation zone (a “zone” is a chamber, enclosed area, etc.) 24, which are used to sense the pressure and the temperature of the preconcentrated weak black liquor just prior to the preconcentrated weak black liquor entering the evaporation zone 24. The preconcentrated weak black liquor is then passed into the evaporation zone 24 through an inlet 26 and a die 28 comprising one or more orifices. The die 28 is constructed such that the pressure drop through the die should prevent the preconcentrated weak black liquor from boiling until it has nearly entered, or has actually entered the evaporation zone. In order for the flash evaporation of the preconcentrated weak black liquor to take place in the evaporation zone 24, pressure is controlled in the evaporation zone 24 such that it is lower than the vapor pressure of the heated preconcentrated weak black liquor as it enters the evaporation zone 24. The strong black liquor is cooled as it passes through the evaporation zone 24 and then goes through an outlet 30.
  • A [0012] vapor exit port 34 is attached to the evaporation zone 24 where the vapor that was evaporated out of the strong black liquor in the evaporation zone 24 is removed from the evaporation zone 24. Another pressure sensor 36 is located outside of the vapor exit port 34 or could be somewhere connected to the evaporation zone 24 itself, and is used to sense the pressure in the evaporation chamber 24 or just outside of it. In order for the vapor to exit the evaporation zone 24 the pressure needs to be lower outside of the evaporation zone 24 than inside. The lower pressure outside of the evaporation zone 24 may be provided by a vacuum system 40 that is connected to the system via a condenser 38 where most of the vapor is condensed for removal. Alternatively, vapors may pass directly to the pressure control or the vacuum system.
  • The strong black liquor is collected in a [0013] collection vessel 42. It is then pumped out of the system by a pump 44. A conditions sensor 46 senses, measure or infers such things as viscosity, pressure, concentration and heating value of the strong black liquor and is found at or near the exit for the strong black liquor or is attached to the collection vessel. These measurements or inferences can be used in controlling the operation of the system.
  • Preconcentrating [0014]
  • The preconcentrating step may be performed using a [0015] preconcentrator 12. Apparatuses that may be used as preconcentrators include, for example, multi-effect evaporators.
  • “Preconcentrating” means removing a portion of at least one volatile component in a solution or liquid medium prior to the first step of a process. [0016]
  • The volatile component of the weak black liquor that is removed or evaporated is mostly or all water. Other ingredients in the weak black liquor may also be evaporated, although that is not most desirable. [0017]
  • Heating [0018]
  • The heating step of the present inventive method is performed in a [0019] heating zone 16. The heating is preferably done using a heat exchanger. The heating step may be performed, however, by any suitable heating means or device. Some examples of other heating means include, but are not limited to, direct steam injection and microwaves.
  • The preconcentrated weak black liquor is heated to a temperature in the heating zone that is suitable so that the preconcentrated weak black liquor will have a temperature that is above the boiling point of the preconcentrated weak black liquor at the pressure in the evaporation zone. [0020]
  • The pressure in the heating zone is maintained so that the preconcentrated weak black liquor is not allowed to boil. The range of pressures depends upon the composition of the preconcentrated weak black liquor and the temperature of the heating zone and of the preconcentrated weak black liquor. [0021]
  • Appropriate temperature and pressure may be calculated using standard thermodynamic relationships. Methods for doing these calculations can be found in references such as R. C. Reid et al., [0022] The Properties of Gases and Liquids, 4th Ed., McGraw-Hill, New York, N.Y., 1987, Chapters 7 and 8, and Appendix A.
  • Evaporation [0023]
  • After being heated in the [0024] heating zone 16, the preconcentrated weak black liquor is passed through an inlet or conduit and through a die 28 or nozzle or some sort of orifice into the evaporation zone itself. The die or nozzle may be of any suitable shape and configuration that allow the heated preconcentrated weak black liquor to pass through into the evaporation zone 24. The shape and/or number of orifice(s) through which it passes may allow for increase in the surface area of the preconcentrated weak black liquor that is exposed in the evaporation zone as it is passed through the zone. The preconcentrated weak black liquor is passed through into the evaporation zone 24 and is flash evaporated. Preferably, the die 28, which is a device having a specific shape or design that it imparts to such material that is passed through it, is of a suitable shape or configuration that allows the preconcentrated weak black liquor to pass through the evaporation zone 24 and be flash evaporated to form strong black liquor. Some die designs will have the added property that the preconcentrated weak black liquor will pass through the evaporation zone 24 and be flash evaporated to form strong black liquor without substantially contacting the inner surface or surfaces 32 of the evaporation zone 24. In some operations this is desirable.
  • An exemplary die has a plurality of orifices or holes that allow the preconcentrated weak black liquor to form strands or streams (that may be discontinuous) as the preconcentrated weak black liquor passes through the [0025] evaporation zone 24. Another possibility is for the die 28 to have orifices that are slits and allow for sheets or curtains (that may be discontinuous) of heated preconcentrated weak black liquor to travel or fall into the evaporation chamber 24. These exemplary designs of the die 28 allow more surface area of preconcentrated weak black liquor to be exposed in the evaporation zone 24, which allows for more efficient evaporation. Other configurations of the die and its orifice or orifices are also contemplated for this invention.
  • The at least one volatile component (volatile component being volatile at the temperature at which the preconcentrated weak black liquor enters the evaporation zone and at the pressure in the evaporation zone) that is evaporated from the preconcentrated weak black liquor to form the strong black liquor is mostly, if not all, water. Other ingredients of the preconcentrated weak black liquor may be evaporated, although that is not most desirable. [0026]
  • The evaporation step relies on the mechanism wherein the energy absorbed by the preconcentrated weak black liquor during the heating step is preserved by maintaining a back pressure on the preconcentrated weak black liquor to prevent vaporization of the preconcentrated weak black liquor in the [0027] inlet 26 to the evaporation zone 24, and is subsequently released in the evaporation zone causing evaporation. The number and size of the orifices in the die 28 affect the back pressure that is maintained upstream. The back pressure must be sufficient to keep the preconcentrated weak black liquor from boiling before it enters the evaporation zone 24.
  • A multi-orifice die may be preferred, particularly because the weak black liquor is to be concentrated or evaporated in a single pass through the evaporation zone. Selection of the number and size of the orifices is used to achieve the desired pressure to prevent boiling of the preconcentrated weak black liquor prior to entering the evaporation zone. [0028]
  • The pressure in the [0029] evaporation zone 24 is controlled so that when the preconcentrated weak black liquor enters the evaporation zone 24 it flash evaporates. The greater the temperature differential of the preconcentrated weak black liquor, the faster will be the rate of evaporation. Flash evaporation is an elementary step in which volatile components, for example, unreacted monomers, solvents or species, are removed. In the case of weak black liquor, the change in pressure allows for flash evaporation of the volatile component(s) from the weak black liquor, resulting in concentration to form strong black liquor.
  • The desired level of pressure necessary in the process may be calculated using, for example, the calculations set forth in Reid et al., The Properties of Gases and Liquids, McGraw-Hill Book Co., 4[0030] th ed., Chapters 7 and 8, and Appendix A.
  • There may be many factors that interact in selecting the target strong black liquor concentration and the present invention can be employed to achieve whatever increased concentration (or level of evaporation) is finally selected relative to the initial concentration. [0031]
  • The strong black liquor will generally have a percent solids of about 45-50 wt % solids before it is fed to the recovery boiler. [0032]
  • Continuous Adjustment [0033]
  • The pressure and/or temperature of the inventive process are periodically or continuously controlled and manually or automatically controlled. This is done using a plurality of temperature and pressure sensors, as described above. In addition, a conditions sensor may be used to monitor the conditions or properties of the remaining (or post-evaporation) strong black liquor. The sensors may be part of a control system(s) that can regulate the pressure and temperature of the pre-evaporation black liquor, evaporation zone, etc. In an exemplary embodiment, one or more of the variables in the inventive process (pressures, temperatures) are regulated by automatic control systems, the set points having been manually supplied by an operator. In another exemplary embodiment, one or more of the closed-loop systems that regulate temperature and pressure will receive set points from another control system, based on directly measured or inferred properties of the post-evaporation strong black liquor. In another exemplary embodiment, the entire inventive process will be controlled by an automatic control system, based on measurements of temperature and/or pressure, and on properties of the post-evaporation strong black liquor. The operator will specify a desired property (such as percent solids content) of the post-evaporation strong black liquor, and the control system will automatically regulate process variables in such a way as to achieve the desired property. [0034]
  • The control system may comprise a single multivariable controller, or several independent single-loop controllers, or a combination of controller types. [0035]
  • Collection [0036]
  • The concentrated black liquor is collected in a [0037] collection vessel 42. A pump may be mounted at, in, or after the collection vessel. A pump should be selected to be of a type that can remove strong black liquor from the collection vessel and pass it at a higher pressure into an ultimate collection vessel of some type, or it could be passed to the recovery boiler (in pulp production process) from the collection vessel. This may be done continuously or periodically.
  • EXAMPLES
  • This invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. In the examples, sucrose solutions were used in place of black liquor. Black liquor is difficult to obtain for laboratory studies unless one is closely associated with a pulp manufacturing plant. It is expected that the sucrose solutions mimicked the behavior of black liquor in the inventive process. In the examples, all parts, ratios and percentages are by weight unless otherwise indicated. The following test method was used to characterize the compositions in the following examples. [0038]
  • Test Method
  • Solids [0039]
  • Dried solids of sucrose solutions were determined from measuring the refractive index of the material and using that measurement to calculate the solids in weight percent. The refractive index of each sample was measured with a Leica Mark II Abbe Refractometer (available from Leica Microsystems, Inc., Depen, N.Y.) with the temperature of the water bath maintained at 25° C. The concentration of each sucrose solution was calculated from the measured refractive index of the solution and a correlation between concentration and refractive index. The correlation between concentration and refractive index was determined from data in “Properties of Sucrose Solutions,” [0040] CRC Handbook of Chemistry and Physics, 53rd Edition, page D-128, The Chemical Rubber Co., Cleveland (1972).
  • The following process was used to make the examples. [0041]
  • Process
  • The material to be concentrated was placed in a pressurized, jacketed feed vessel kept at 240 kPa (20 psig) and 40° C. This material was continuously fed to the evaporation zone using the pressure in the feed tank and a valve to adjust the flow of liquid. The feed was heated by passing through a custom-made heat exchanger consisting of a jacketed tube inside an outer tube. The feed passed through the inner tube that had a length of about 610 mm (24 in) and an outer diameter of about 6.3 mm (0.25 in). Temperature controlled water passed through the outer tube that had a diameter of about 25 mm (1 in). The material next passed through a custom-made die containing a single hole or orifice, about 1.09 mm (0.043 in) in diameter, before entering the evaporation zone. The evaporation zone consisted of a vertical portion comprising a CLAISEN™ adapter, available as Part No. 5135 from Ace Glass Inc., Vineland, N.J. A side arm came off the vertical portion and sloped upward to a vertical 10/30 joint, which was connected to a pressure transducer (Model number 1151AP5E333B1, available from Rosemount, Inc., Chanhassen, Minn.). Another side arm sloping off the side arm described immediately above had a male 24/40 fitting that was connected to a water aspirator vacuum system (custom-made). The concentrated material was continuously removed from the evaporation zone using an air-driven pump (Model FH432 from Viking Pump, Inc., Cedar Falls, Iowa). [0042]
  • Small jars were filled with the product leaving the evaporation zone. Each jar was filled for 1 minute and then replaced with a next one. Refractive index of the material in each of the jars was measured. The concentrations of the sucrose solutions were calculated from the measured refractive index of the solutions and the correlation between concentration and refractive index. The correlation between concentration and refractive index was determined from data presented in “Properties of Sucrose Solutions,” [0043] CRC Handbook of Chemistry and Physics, 53rd Edition, page D-128, The Chemical Rubber Co., Cleveland (1972).
  • Example 1
  • This Example illustrates the response time for a pressure only change. [0044]
  • A sucrose solution (Refractive Index=1.4545, Concentration=64.8 wt %) was placed in the feed tank, and flow was begun to the evaporation zone. Conditions were allowed to stabilize at a heat exchanger temperature of 71° C. and an evaporation zone pressure of 9.3 kPa (70 torr). The pressure was changed and stabilized at between 5.6 and 5.7 kPa (between 42 and 43 torr). After a period of time the pressure was changed again and stabilized at between 2.8 and 2.9 kPa (21 and 22 torr). [0045]
  • Solids wt % was determined for all samples. Pressure, refractive index and calculated solids wt % are shown in Table 1 with elapsed time. [0046]
    TABLE 1
    Elapsed Time Pressure Refractive Index
    Sample min kPa (torr) at 25° C. Wt % Solids
    A 3 9.3 (70) 1.4574 66.1
    B 4 Change P 1.4574 66.1
    C 5 5.7 (43) 1.4592 66.8
    D 6 5.7 (43) 1.4621 68.1
    E 7 5.7 (43) 1.4604 67.4
    F 8 5.7 (43) 1.4593 66.9
    G 9 5.7 (43) 1.4607 67.5
    H 10 5.7 (43) 1.4600 67.2
    I 11 5.6 (42) 1.4600 67.2
    J 12 5.6 (42) 1.4603 67.3
    K 13 Change P 1.4605 67.4
    L 14 2.9 (22) 1.4603 67.3
    M 15 2.9 (22) 1.4646 69.2
    N 16 2.9 (22) 1.4641 69.0
    O 17 2.9 (22) 1.4639 68.9
    P 18 2.8 (21) 1.4633 68.6
    Q 19 2.8 (21) 1.4633 68.6
    R 20 2.8 (21) 1.4631 68.5
    S 21 2.8 (21) 1.4633 68.6
    T 22 2.8 (21) 1.4632 68.6
    U 23 2.8 (21) 1.4631 68.5
  • Example 2
  • This Example illustrates the response time for a temperature change only. [0047]
  • A sucrose solution (Refractive Index=1.4545, Concentration=64.8 wt %) was placed in the feed tank, and flow was begun to the evaporation zone. Conditions were allowed to stabilize at a heat exchanger temperature of 57° C. and an evaporation zone pressure of between 5.1 and 5.2 kPa (between 38 and 39 torr). The temperature was changed and stabilized at 70° C. After a period of time the temperature was changed again and stabilized at 83° C. [0048]
  • Solids wt % was determined for all samples. Temperature, refractive index and calculated solids wt % are shown in Table 2 with elapsed time. [0049]
    TABLE 2
    Elapsed Time Temperature Refractive Index
    Sample min ° C. at 25° C. Wt % Solids
    A 11 57 1.4584 66.5
    B 12 Change T 1.4584 66.5
    C 13 57 1.4584 66.5
    D 14 58 1.4585 66.5
    E 15 63 1.4595 67.0
    F 16 66 1.4607 67.5
    G 17 68 1.4610 67.6
    H 18 69 1.4612 67.7
    I 19 69 1.4611 67.7
    J 20 70 1.4615 67.8
    K 21 70 1.4615 67.8
    L 22 70 1.4614 67.8
    M 23 70 1.4611 67.7
    N 24 70 1.4609 67.6
    O 25 70 1.4612 67.7
    P 26 Change T 1.4611 67.7
    Q 27 70 1.4618 68.0
    R 28 73 1.4616 67.9
    S 29 79 1.4623 68.2
    T 30 81 1.4634 68.7
    U 31 81 1.4641 69.0
    V 32 82 1.4646 69.2
    W 33 83 1.4648 69.3
    X 34 83 1.4645 69.1
    Y 35 82 1.4649 69.3
    Z 36 84 1.4649 69.3
    AA 37 84 1.4648 69.3
    AB 38 82 1.4643 69.0
    AC 39 82 1.4643 69.0
    AD 40 83 1.4640 68.9
    AE 41 83 1.4644 69.1
    AF 42 83 1.4645 69.1
    AG 43 83 1.4642 69.0
  • The easiest way to compare the dynamics of the changes in Examples 1 and 2 was to plot the normalized change in solids concentration versus the time after a deliberate change occured in the set-point of either the pressure or the temperature. FIG. 2 shows the normalized solids % changes as they relate to changes in the pressure or temperature for Examples 1 and 2 from the start of each change in condition. As seen, the response to a change in pressure was much faster than the response to a change in temperature. One can compensate for the overshoot that occurred with a pressure change using standard methods known to those skilled in the art of process control. This would result in pressure control as a primary means of control of evaporation processes that would be much more rapid than that obtainable with temperature control alone. [0050]

Claims (7)

What is claimed is:
1. A process for concentrating weak black liquor to form strong black liquor, said process comprising:
a. preconcentrating said weak black liquor;
b. heating said preconcentrated weak black liquor in a heating zone under sufficient pressure to prevent said preconcentrated weak black liquor from boiling in said heating zone;
c. passing said preconcentrated weak black liquor, having at least one volatile component, into an evaporation zone through one or more orifices;
d. applying pressure in said evaporation zone that is lower than the vapor pressure of said preconcentrated weak black liquor as it is passed into said evaporation zone, which allows for flash evaporation of at least a portion of said at least one volatile component of said preconcentrated weak black liquor from said preconcentrated weak black liquor to form strong black liquor;
e. adjusting temperature in said heating zone, pressure in said heating zone and pressure in said evaporation zone to allow for evaporation of an amount of said at least one volatile component from said preconcentrated weak black liquor to form said strong black liquor; and
f. collecting said strong black liquor from said evaporation zone.
2. The method of claim 1 wherein said evaporation zone has at least one inner surface, and wherein said preconcentrated weak black liquor does not substantially contact said at least one inner surface of said evaporation zone as said preconcentrated weak black liquor passes through said evaporation zone.
3. The method of claim 1 wherein said one or more orifices are shaped such that a desired surface area of said preconcentrated weak black liquor is exposed in said evaporation zone.
4. The method of claim 1 wherein said pressure in said heating zone and/or said pressure in said evaporation zone are regulated using one or more pressure sensors.
5. The method of claim 1 wherein the temperature of the preconcentrated weak black liquor prior to said preconcentrated weak black liquor passing into said evaporation zone is regulated using one or more temperature sensors.
6. The method of claim 1 wherein a conditions sensor monitors the conditions of the strong black liquor after it is collected from said evaporation zone.
7. The method of claim 1 wherein conditions or properties of the strong black liquor are controlled by regulating the pressure in said evaporation zone and/or by regulating the temperature of the preconcentrated weak black liquor as it is passed into said evaporation zone.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070179216A1 (en) * 2005-05-02 2007-08-02 Degussa Ag Method for producing aqueous polyurethane dispersions by means of flash evaporation
CN105088848A (en) * 2015-09-07 2015-11-25 武汉凯比思电力设备有限公司 Pulp paper black liquor hyperconcentration device, pulp and paper black liquor treatment system as well as methods
JP2016017857A (en) * 2014-07-09 2016-02-01 公益財団法人鉄道総合技術研究所 Measuring method of moisture content in soil

Citations (72)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2801168A (en) * 1949-04-02 1957-07-30 Goddard Harold Oliver Waste sulphite liquor recovery
US2816831A (en) * 1949-04-02 1957-12-17 Goddard Harold Oliver Process for producing and concentrating residual waste sulphite liquor
US3036057A (en) * 1959-08-12 1962-05-22 Phillips Petroleum Co Flash concentration of solutions containing polyolefins
US3047362A (en) * 1958-12-29 1962-07-31 Combustion Eng Treatment of waste liquors
US3168588A (en) * 1960-09-14 1965-02-02 Exxon Research Engineering Co Polymerized ethylene lubricating oils from alkanol modified catalysts
US3201365A (en) * 1961-06-26 1965-08-17 Dow Chemical Co Recovering polymer from dilute polymer solutions
US3444052A (en) * 1967-12-11 1969-05-13 Phillips Petroleum Co Flash vaporization with vapor flow streams controlled by liquid level
US3453184A (en) * 1963-09-27 1969-07-01 Mobay Chemical Corp Removal of high and low boiling solvents from polycarbonate solutions
US3470070A (en) * 1966-12-06 1969-09-30 Phillips Petroleum Co Flashing viscous polymer solutions
US3493470A (en) * 1966-05-27 1970-02-03 Phillips Petroleum Co Volatile components by vaporization while maintaining the desired rate of vaporization by overhead flow control
US3495648A (en) * 1968-03-11 1970-02-17 Pet Inc Microwave apparatus for evaporating liquid mixtures
US3538193A (en) * 1967-04-06 1970-11-03 Copolymer Rubber & Chem Corp Recovery of polymeric materials from organic reaction mixtures
US3582104A (en) * 1969-09-02 1971-06-01 Budd Co Pivotal axle mounting for an aircraft transfer vehicle
US3582365A (en) * 1970-04-27 1971-06-01 Food Enterprises Inc Method and apparatus for treating milk and other liquid products
US3585104A (en) * 1968-07-29 1971-06-15 Theodor N Kleinert Organosolv pulping and recovery process
US3586089A (en) * 1967-05-02 1971-06-22 Mitsui Petrochemical Ind Method and apparatus for separating and drying organic high molecular weight substances
US3618588A (en) * 1969-01-14 1971-11-09 Pepsico Inc Caramel color manufacture
US3624300A (en) * 1966-05-11 1971-11-30 Superior Continental Corp Central office terminal unit for telephone carrier system
US3634300A (en) * 1969-11-08 1972-01-11 Basf Ag Removing unreacted monomers from acrylonitrile polymer solutions and concentration of the solutions
US3635917A (en) * 1969-07-09 1972-01-18 Chemiefaserwerk Friedrick Enge Method of producing highly concentrated acrylonitrile polymer and copolymer solutions
US3642492A (en) * 1967-06-01 1972-02-15 Ralston Purina Co Method of preparing a simulated skim milk
US3656534A (en) * 1969-05-06 1972-04-18 Parkson Corp Concentration by continuous flash evaporation
US3668161A (en) * 1969-06-09 1972-06-06 Union Carbide Corp Devolatilization of liquid polymer compositions
US3738409A (en) * 1971-01-27 1973-06-12 Welding Engineers Apparatus for flash-concentrating viscous liquids
US3773658A (en) * 1970-06-08 1973-11-20 Inst Francais Du Petrole Process for regenerating used lubricating oils
US3799234A (en) * 1971-02-22 1974-03-26 Welding Engineers Countercurrent vapor stripping in screw devolatilizer
US3816240A (en) * 1972-06-21 1974-06-11 W Franz Minimizing sulfur oxidation in pulping liquor reconstitution
US3852503A (en) * 1972-01-19 1974-12-03 Ralston Purina Co Method of making puddings containing soy protein
US3853839A (en) * 1972-01-19 1974-12-10 Ralston Purina Co Method of forming protein food product
US3862014A (en) * 1971-01-26 1975-01-21 Florida State Distillation apparatus for recovering citrus essence
US3893940A (en) * 1971-11-05 1975-07-08 Lion Fat Oil Co Ltd Method of manufacturing surface active agent having low content of unreacted oil
US3901673A (en) * 1972-12-15 1975-08-26 Phillips Petroleum Co Recovery of natural gas liquids by partial condensation
US3920505A (en) * 1972-08-09 1975-11-18 Donald Edmund Helleur Method and apparatus for removing volatile fluids
US3941664A (en) * 1972-08-29 1976-03-02 Phillips Petroleum Company Control for diluent removal from poly(arylene sulfide) reactor product
US3966538A (en) * 1973-01-09 1976-06-29 Monsanto Company Falling strand devolatilization apparatus
US4038129A (en) * 1975-07-09 1977-07-26 Wreszinski Rolf W Method and apparatus for concentrating liquids
US4239589A (en) * 1978-10-02 1980-12-16 Air Products And Chemicals, Inc. Process for oxidation of black liquor
US4255314A (en) * 1979-07-12 1981-03-10 Denki Kagaku Kogyo Kabushiki Kaisha Method for the manufacture of a vinyl chloride copolymer solution
US4294652A (en) * 1980-06-30 1981-10-13 Monsanto Company Falling strand devolatilizer
US4314827A (en) * 1979-06-29 1982-02-09 Minnesota Mining And Manufacturing Company Non-fused aluminum oxide-based abrasive mineral
US4375524A (en) * 1981-06-26 1983-03-01 Phillips Petroleum Company Process control for flash concentrating solutions containing polyolefins
US4394219A (en) * 1980-06-23 1983-07-19 Merix Corporation Fractionating liquids
US4414341A (en) * 1980-11-19 1983-11-08 Celanese Corporation Flash evaporation process for concentrating polymer solutions
US4495028A (en) * 1981-06-26 1985-01-22 Phillips Petroleum Company Process control for flash concentrating solutions containing polyolefins
US4530737A (en) * 1982-09-20 1985-07-23 Ekono Oy Method for use in recompression evaporation of a solution
US4551198A (en) * 1982-03-30 1985-11-05 Kamyr, Inc. Method of flashing black liquor
US4555309A (en) * 1983-08-19 1985-11-26 Phillips Petroleum Company Control of a fractional distillation process
US4558423A (en) * 1983-05-27 1985-12-10 Phillips Petroleum Company Utilization of an ASTM end point temperature for controlling a fractional distillation process
US4629663A (en) * 1984-10-29 1986-12-16 Minnesota Mining And Manufacturing Company Removable pressure-sensitive adhesive tape
US4686086A (en) * 1981-06-26 1987-08-11 Phillips Petroleum Company Process system including fluid flow control apparatus
US4692482A (en) * 1986-01-14 1987-09-08 Huls Aktiengesellschaft Method of concentrating polyphenylene ether solutions
US4718978A (en) * 1984-03-21 1988-01-12 James River Corporation Of Nevada Spent pulping liquor recovery process
US4857146A (en) * 1985-06-07 1989-08-15 Andersson Alf Ove Process for increasing the solids content of black liquor at its recovery in a sulfate pulping 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
US4931414A (en) * 1985-11-22 1990-06-05 Minnesota Mining And Manufacturing Company Thermal extractive gelation process
US5061472A (en) * 1989-08-23 1991-10-29 Bayer Aktiengesellschaft Process for the concentration of sulphuric acid containing metal sulphates
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
US5143579A (en) * 1991-07-31 1992-09-01 International Paper Company Treatment of black liquor with a screw extruder evaporator
US5277759A (en) * 1990-07-09 1994-01-11 A. Ahlstrom Corporation Method of controlling sulfidity of a sulfate cellulose mill
US5360513A (en) * 1992-02-13 1994-11-01 A. Ahlstrom Corporation Sulphur removal from gases associated with boilers having cascade evaporators
US5368668A (en) * 1992-05-07 1994-11-29 Minnesota Mining And Manufacturing Company Stitchbonded absorbent articles and method of making same
US5472568A (en) * 1993-09-07 1995-12-05 Air Products And Chemicals, Inc. Method for controlling the viscosity of Kraft black liquor
US5662774A (en) * 1992-04-01 1997-09-02 Tampella Power Oy Adjusting the sulphur balance of a sulphate cellulose plant by heat treating black liquor in a last evaporation stage
US5723433A (en) * 1993-09-24 1998-03-03 The Chemithon Corporation Sovent removal process
US5730836A (en) * 1991-12-31 1998-03-24 Comalco Aluminium Limited Evaporative concentration of clay slurries
US5868805A (en) * 1993-11-26 1999-02-09 Kvaerner Pulping Ab Process for integrated evaporation and gasification of spent liquor from cellulose cooking
US5968312A (en) * 1992-08-06 1999-10-19 Sephton; Hugo H. Liquid flow distribution and flow control with dual adjustable orifice plates or overlapping orifices
US6454907B1 (en) * 1999-04-19 2002-09-24 Minerals Technologies, Inc. Method and apparatus for concentrating slurried solids
US6471823B1 (en) * 1998-04-29 2002-10-29 Fisher-Rosemount Systems, Inc. Use of pressure and temperature measurements to infer process variables and to monitor equipment conditions and infer process efficiency in a multi-effect evaporator system
US6524436B2 (en) * 1999-06-14 2003-02-25 Andritz, Inc. Flash tank steam economy improvement

Patent Citations (72)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2816831A (en) * 1949-04-02 1957-12-17 Goddard Harold Oliver Process for producing and concentrating residual waste sulphite liquor
US2801168A (en) * 1949-04-02 1957-07-30 Goddard Harold Oliver Waste sulphite liquor recovery
US3047362A (en) * 1958-12-29 1962-07-31 Combustion Eng Treatment of waste liquors
US3036057A (en) * 1959-08-12 1962-05-22 Phillips Petroleum Co Flash concentration of solutions containing polyolefins
US3168588A (en) * 1960-09-14 1965-02-02 Exxon Research Engineering Co Polymerized ethylene lubricating oils from alkanol modified catalysts
US3201365A (en) * 1961-06-26 1965-08-17 Dow Chemical Co Recovering polymer from dilute polymer solutions
US3453184A (en) * 1963-09-27 1969-07-01 Mobay Chemical Corp Removal of high and low boiling solvents from polycarbonate solutions
US3624300A (en) * 1966-05-11 1971-11-30 Superior Continental Corp Central office terminal unit for telephone carrier system
US3493470A (en) * 1966-05-27 1970-02-03 Phillips Petroleum Co Volatile components by vaporization while maintaining the desired rate of vaporization by overhead flow control
US3470070A (en) * 1966-12-06 1969-09-30 Phillips Petroleum Co Flashing viscous polymer solutions
US3538193A (en) * 1967-04-06 1970-11-03 Copolymer Rubber & Chem Corp Recovery of polymeric materials from organic reaction mixtures
US3586089A (en) * 1967-05-02 1971-06-22 Mitsui Petrochemical Ind Method and apparatus for separating and drying organic high molecular weight substances
US3642492A (en) * 1967-06-01 1972-02-15 Ralston Purina Co Method of preparing a simulated skim milk
US3444052A (en) * 1967-12-11 1969-05-13 Phillips Petroleum Co Flash vaporization with vapor flow streams controlled by liquid level
US3495648A (en) * 1968-03-11 1970-02-17 Pet Inc Microwave apparatus for evaporating liquid mixtures
US3585104A (en) * 1968-07-29 1971-06-15 Theodor N Kleinert Organosolv pulping and recovery process
US3618588A (en) * 1969-01-14 1971-11-09 Pepsico Inc Caramel color manufacture
US3656534A (en) * 1969-05-06 1972-04-18 Parkson Corp Concentration by continuous flash evaporation
US3668161A (en) * 1969-06-09 1972-06-06 Union Carbide Corp Devolatilization of liquid polymer compositions
US3635917A (en) * 1969-07-09 1972-01-18 Chemiefaserwerk Friedrick Enge Method of producing highly concentrated acrylonitrile polymer and copolymer solutions
US3582104A (en) * 1969-09-02 1971-06-01 Budd Co Pivotal axle mounting for an aircraft transfer vehicle
US3634300A (en) * 1969-11-08 1972-01-11 Basf Ag Removing unreacted monomers from acrylonitrile polymer solutions and concentration of the solutions
US3582365A (en) * 1970-04-27 1971-06-01 Food Enterprises Inc Method and apparatus for treating milk and other liquid products
US3773658A (en) * 1970-06-08 1973-11-20 Inst Francais Du Petrole Process for regenerating used lubricating oils
US3862014A (en) * 1971-01-26 1975-01-21 Florida State Distillation apparatus for recovering citrus essence
US3738409A (en) * 1971-01-27 1973-06-12 Welding Engineers Apparatus for flash-concentrating viscous liquids
US3799234A (en) * 1971-02-22 1974-03-26 Welding Engineers Countercurrent vapor stripping in screw devolatilizer
US3893940A (en) * 1971-11-05 1975-07-08 Lion Fat Oil Co Ltd Method of manufacturing surface active agent having low content of unreacted oil
US3853839A (en) * 1972-01-19 1974-12-10 Ralston Purina Co Method of forming protein food product
US3852503A (en) * 1972-01-19 1974-12-03 Ralston Purina Co Method of making puddings containing soy protein
US3816240A (en) * 1972-06-21 1974-06-11 W Franz Minimizing sulfur oxidation in pulping liquor reconstitution
US3920505A (en) * 1972-08-09 1975-11-18 Donald Edmund Helleur Method and apparatus for removing volatile fluids
US3941664A (en) * 1972-08-29 1976-03-02 Phillips Petroleum Company Control for diluent removal from poly(arylene sulfide) reactor product
US3901673A (en) * 1972-12-15 1975-08-26 Phillips Petroleum Co Recovery of natural gas liquids by partial condensation
US3966538A (en) * 1973-01-09 1976-06-29 Monsanto Company Falling strand devolatilization apparatus
US4038129A (en) * 1975-07-09 1977-07-26 Wreszinski Rolf W Method and apparatus for concentrating liquids
US4239589A (en) * 1978-10-02 1980-12-16 Air Products And Chemicals, Inc. Process for oxidation of black liquor
US4314827A (en) * 1979-06-29 1982-02-09 Minnesota Mining And Manufacturing Company Non-fused aluminum oxide-based abrasive mineral
US4255314A (en) * 1979-07-12 1981-03-10 Denki Kagaku Kogyo Kabushiki Kaisha Method for the manufacture of a vinyl chloride copolymer solution
US4394219A (en) * 1980-06-23 1983-07-19 Merix Corporation Fractionating liquids
US4294652A (en) * 1980-06-30 1981-10-13 Monsanto Company Falling strand devolatilizer
US4414341A (en) * 1980-11-19 1983-11-08 Celanese Corporation Flash evaporation process for concentrating polymer solutions
US4686086A (en) * 1981-06-26 1987-08-11 Phillips Petroleum Company Process system including fluid flow control apparatus
US4495028A (en) * 1981-06-26 1985-01-22 Phillips Petroleum Company Process control for flash concentrating solutions containing polyolefins
US4375524A (en) * 1981-06-26 1983-03-01 Phillips Petroleum Company Process control for flash concentrating solutions containing polyolefins
US4551198A (en) * 1982-03-30 1985-11-05 Kamyr, Inc. Method of flashing black liquor
US4530737A (en) * 1982-09-20 1985-07-23 Ekono Oy Method for use in recompression evaporation of a solution
US4558423A (en) * 1983-05-27 1985-12-10 Phillips Petroleum Company Utilization of an ASTM end point temperature for controlling a fractional distillation process
US4555309A (en) * 1983-08-19 1985-11-26 Phillips Petroleum Company Control of a fractional distillation process
US4718978A (en) * 1984-03-21 1988-01-12 James River Corporation Of Nevada Spent pulping liquor recovery process
US4629663A (en) * 1984-10-29 1986-12-16 Minnesota Mining And Manufacturing Company Removable pressure-sensitive adhesive tape
US5112441A (en) * 1985-04-25 1992-05-12 Oy Tampella Ab Process for the recovery of heat and chemicals from spent liquor
US4857146A (en) * 1985-06-07 1989-08-15 Andersson Alf Ove Process for increasing the solids content of black liquor at its recovery in a sulfate pulping process
US4931414A (en) * 1985-11-22 1990-06-05 Minnesota Mining And Manufacturing Company Thermal extractive gelation process
US4692482A (en) * 1986-01-14 1987-09-08 Huls Aktiengesellschaft Method of concentrating polyphenylene ether solutions
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
US5061472A (en) * 1989-08-23 1991-10-29 Bayer Aktiengesellschaft Process for the concentration of sulphuric acid containing metal sulphates
US5277759A (en) * 1990-07-09 1994-01-11 A. Ahlstrom Corporation Method of controlling sulfidity of a sulfate cellulose mill
US5143579A (en) * 1991-07-31 1992-09-01 International Paper Company Treatment of black liquor with a screw extruder evaporator
US5730836A (en) * 1991-12-31 1998-03-24 Comalco Aluminium Limited Evaporative concentration of clay slurries
US5360513A (en) * 1992-02-13 1994-11-01 A. Ahlstrom Corporation Sulphur removal from gases associated with boilers having cascade evaporators
US5662774A (en) * 1992-04-01 1997-09-02 Tampella Power Oy Adjusting the sulphur balance of a sulphate cellulose plant by heat treating black liquor in a last evaporation stage
US5368668A (en) * 1992-05-07 1994-11-29 Minnesota Mining And Manufacturing Company Stitchbonded absorbent articles and method of making same
US5968312A (en) * 1992-08-06 1999-10-19 Sephton; Hugo H. Liquid flow distribution and flow control with dual adjustable orifice plates or overlapping orifices
US5472568A (en) * 1993-09-07 1995-12-05 Air Products And Chemicals, Inc. Method for controlling the viscosity of Kraft black liquor
US5723433A (en) * 1993-09-24 1998-03-03 The Chemithon Corporation Sovent removal process
US5868805A (en) * 1993-11-26 1999-02-09 Kvaerner Pulping Ab Process for integrated evaporation and gasification of spent liquor from cellulose cooking
US6471823B1 (en) * 1998-04-29 2002-10-29 Fisher-Rosemount Systems, Inc. Use of pressure and temperature measurements to infer process variables and to monitor equipment conditions and infer process efficiency in a multi-effect evaporator system
US6454907B1 (en) * 1999-04-19 2002-09-24 Minerals Technologies, Inc. Method and apparatus for concentrating slurried solids
US6524436B2 (en) * 1999-06-14 2003-02-25 Andritz, Inc. Flash tank steam economy improvement

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070179216A1 (en) * 2005-05-02 2007-08-02 Degussa Ag Method for producing aqueous polyurethane dispersions by means of flash evaporation
JP2016017857A (en) * 2014-07-09 2016-02-01 公益財団法人鉄道総合技術研究所 Measuring method of moisture content in soil
CN105088848A (en) * 2015-09-07 2015-11-25 武汉凯比思电力设备有限公司 Pulp paper black liquor hyperconcentration device, pulp and paper black liquor treatment system as well as methods

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