US3859052A - Crystallization apparatus having pressure-liquid level control means - Google Patents

Crystallization apparatus having pressure-liquid level control means Download PDF

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Publication number
US3859052A
US3859052A US280928A US28092872A US3859052A US 3859052 A US3859052 A US 3859052A US 280928 A US280928 A US 280928A US 28092872 A US28092872 A US 28092872A US 3859052 A US3859052 A US 3859052A
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Prior art keywords
chamber
crystallization
liquid
vacuum
pressure
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US280928A
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English (en)
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Hans Walther
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JOH A BENCKISER CHEM FAB GmbH
JOH A BENCKISER CHEMISCHE FABRIK GmbH
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JOH A BENCKISER CHEM FAB GmbH
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Priority to US280928A priority Critical patent/US3859052A/en
Priority to DE2326753A priority patent/DE2326753A1/de
Priority to IT25276/73A priority patent/IT989085B/it
Priority to JP48080002A priority patent/JPS4958080A/ja
Priority to IL42815A priority patent/IL42815A/en
Priority to IE1285/73A priority patent/IE37955B1/xx
Priority to FR7329518A priority patent/FR2196183B1/fr
Priority to NL7311196A priority patent/NL7311196A/xx
Priority to BE134557A priority patent/BE803588A/xx
Priority to GB3858973A priority patent/GB1447281A/en
Priority to BR6287/73A priority patent/BR7306287D0/pt
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/0018—Evaporation of components of the mixture to be separated
    • B01D9/0022—Evaporation of components of the mixture to be separated by reducing pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/0018—Evaporation of components of the mixture to be separated
    • B01D9/0031—Evaporation of components of the mixture to be separated by heating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/0063—Control or regulation

Definitions

  • the invention relates to crystallization equipment and, in particular, to such equipment which is capable of producing, by means of a crystallization process operating either intermittently or continuously, crystals of such compounds which normally exhibit a tendency to cake (adhering together) and/or to adhere to the equipment walls.
  • the process of the invention comprises circulating a solution of the solid to be crystallized out between a vacuum zone and a crystalli2ation zone maintained preferably at no less than atmospheric pressure, desirably above it.
  • the liquid is supplied with enough heat so that it will be vaporized in part.
  • the liquid is circulated through a heating zone, theprocess comprising the additional aspect of heating the liquid, preferably prior to feeding it to the vacuum zone to a temperature high enough to vaporize a part of the solvent of the solution then passing th e liquid to the vacuum zone.
  • the level of the liquid in the vacuum is kept constant. This is accomplished by regulating the pressure differential between the vacuum and crystallization zones in relation to the density of the crystal suspension. Difficult to crystallize materials are obtained as well formed crystals in a high degree of purity.
  • the apparatus and process of the invention is useful to crystallize out of solution (aqueous or from other organic solvents like alcohols, ester, ethers, hydrocarbons halogenated or not for instance parafinic hydro carbons) any crystalline compound or material.
  • the invention is especially valuable in obtaining the acids which are normally obtained from fermentations like gluconic, itacanic, citric, fumaric, especially polycarboxylic acids, and their soluble salts.
  • the process and apparatus are also very useful in crystallization of other organic acids like oxalic acid, adipic, malic, sartaric and other polycarbonylic acids or various salts thereof.
  • the crystallization equipment comprises an upper chamber and a lower crystallization chamber connected to each other by two conduits, the respective lower end of which are immersed in the solution within the lower crystallization chamber.
  • the minimum length of these conduits is such that the suspension of crystals can be withdrawn under barometric conditions.
  • One of the conduits contains a heat exchanger preferably in its upper portion and is so dimensioned that a flow velocity is obtained which is sufficient to entrain the crystals upwardly in the conduit.
  • the lower crystallization chamber contains means for providing agitation of the solution like an agitator. Means are also provided to affect and control the liquid level in the upper chamber to a constant level.
  • the lower crystallization chamber is dimensioned, preferably sufficiently large to contain all the liquid which is present in the crystallization equipment.
  • the solution can be fed selectively either into the lower crystallization chamber, or be delivered to the side walls of the upper chamber by means of a distribution arrangement having one or more inlets.
  • FIG. 1 illustrates a preferred crystallization equipment in accordance with the invention.
  • FIGURE there is shown upper chamber 1, lower crystallization chamber 2, descending conduit 3 and ascending conduit 4 with heat exchanger 5, agitator 6, lower raw material inlet 7 and upper raw material inlet 8 for selectively feeding the crystallization equipment according to the invention, outlet 9 for withdrawal of the crystal suspension, connection 10 to a vacuum pump (not shown), compressed air connection 11, and pressure relief valve 12 for regulating the pres sure in the lower crystallization chamber 2 with the aid of pressure regulator 14 which is actuated by level regulator l3, and finally differential pressure meter 15.
  • heat exchanger 5 the heat needed for vaporation of the solvent is supplied.
  • a part of the solvent evaporates in the upper region of heat exchanger 5 and the vapor bubbles so created cause the circulation of the solution through upper chamber 1, chamber 2, through conduits 3 and 4, in accordance with the principle of mammoth-pump.
  • Heat exchanger 5 is best positioned in the uppermost part of ascending conduit 4 to promote the formation of vapor bubbles in the heating conduits and to bring about as high as possible an overall heat transfer coefficient by the resulting turbulence of the streaming liquid. Concurrently in this manner, there is prevented an overheating of the crystal suspension since the supplied heat is converted essentially immediately to vaporizing heat. The resulting somewaht more limited circulation rate is adequately compensated by these advantages. While circulation of liquids by means of rising vapor bubbles is, in itself, not new, the application of this principle to evaporation crystallizers is new, in accordance with the invention.
  • conduit 4 be so dimensioned that the upward velocity of the suspension is somewhat greater than the sedimentation rate of the crystals.
  • the internal cross-section of ascending conduit 4 can be between 0.1 and 1.0 times the internal cross-section of all the tubes of heat exchanger 5, being preferably between 0.3 and 0.7 times.
  • ascending conduit 4 extend deep enough into lower crystallization chamber 2, so that a suspension rises in this conduit and also to prevent a breakthrough of the gas phase from chamber 2 into chamber 1. Should the velocity of ascent become so low that the crystal suspension begins to precipitate, then one can intermittently introduce additional raw material, in portions or all at once, into lower crystallization chamber 2. In this manner, the suspension flowing downwardly within descending conduit 3 is not diluted or diluted relatively little and the circulation rate isincreased as a result of the greater density of the descending suspension in conduit 3. This measure may be desirable case, for example, during start-up of the equipment.
  • Lower raw material inlet 7 can be connected directly to the lower part of ascending conduit 4, or else to lower crystallizationichamber 2.
  • inlet 7 it is preferable to connect inlet 7 to the upper part of the lower crystallization chamber 2. Since lower inlet 7 is only used intermittently, if the connection is made to ascending conduit 4, crystal lumps might tend to collect in the blind pipe section. It is therefore preferable to connect inlet 7 to the upper part of the lower crystallization chamber 2. Generally, fresh input of solutions is made to upper chamber 1 at 8.
  • upper raw material inlet 8 is made therefore desirably of a perforated pipe. Since the wall encrustations are not distributed uniformly around the circumference of upper chamber 1, upper raw material inlet 8 is preferably sub-divided into individualperforated pipe segments, which can be supplied with raw material in proportion to and selectively as there is need to minimize the development of encrustations of crystals. Although the raw material supply consists of a nearly saturated solution, rinsing of the walls suffices to keep crystal growth within desired limits.
  • Agitator 6 or other agitation means provided in the lower crystallization chamber 2 maintains the crystals in suspension and thus prevents, by its agitating action, the deposition or caking of crystals onto the walls of lower crystallization chamber 2.
  • the greatest proportion of the crystallization takes place in lower crystallization chamber 2 can be demonstrated by measurement of the heat of crystallization developed therein.
  • crystallization takes place principally in chamber 2 and agitator 6 keeps the crystals in suspension, there is obtained surprisingly at outlet 9 large crystals with satisfactory grain size distribution. Above all, however, the crystals also exhibit the desired hardness.
  • Lower crystallization chamber 2 is, according to a preferred aspect of the invention, so dimensioned to be capable of receiving the entire liquid content on the crystallization apparatus. This makes it unnecessary to empty the equipment during brief stoppages and permits, when operation resumes, rapid re-establishment of the original flow and equilibrium throughout the entire system. It then becomes unnecessary to go through the slow process of establishing the desired operating parameters which is otherwise required, as, for example, the density of crystal content of the suspension, the crystal size, etc. when a conventional apparatus is refilled with a fresh solution. Moreover, this dimensioning of lower crystallization chamber 2 is also advantageous for batch operation of the crystallization equipment. At the end of one charge, or batch, it is possible to release the partial vacuum in upper chamber 1, thereby draining its liquid content all at once into lower crystallization chamber 2, and avoiding the possible formation of crystal deposits during emptying, especially in heat exhanger 5.
  • the crystal content of the suspension can be determined by reference to its specific gravity, as follows. It is well known that in communicating conduits the parameters of liquid depth, pressure and specific gravity are related as follows:
  • H, and H are the heights of the liquid levels in the respective conduits, P, and P are the gas pressures to which these liquids are respectively subjected, and y is the specific gravity of the liquid.
  • Equation (1) above can be rewritten as follows:
  • P, and H represent pressure 'and liquid level height in upper chamber 1 respectively, and P and H the corresponding values in lower chamber 2.
  • conduits 3 and 4 are primarily dependent on the vacuum in chamber 1 and from the specific gravity of the liquid to be crystallized and from the resulting crystalline suspension. Their lengths are so selected that there is established a level in chamber 1, which is preferably maintained constant, by applying a pressure slightly above the atmospheric pressure prevailing in the gas space in chamber 2. There is, of course, quite some leeway in the range of pressures in chamber 2, in the vacuum in chamber 1 and the position of the liquid level in chamber 1; hence the heights of the coluums can be adjusted to a practical length as may be best under the circumstances. Maintaining the pressure in chamber 2 at slightly over atmospheric eliminates the need for a pump for the removal of the crystalline product, the walls of the chamber can be of simpler or lighter-weight construction than with conventional equipment where the chamber of crystallization is under vacuum.
  • the apparatus and process of the invention combines therefore a unique operative arrangement in a vaporization zone under vacuum (or connected to a vacuum zone) and a crystallization zone under a pressure other than vacuum generally at a pressure slightly above atmospheric.
  • the operation is unexpectedly efficient and successful.
  • an auxiliary pump for example, can be installed in the equipment ot assist in circulating the crystalline suspension through the system if thermal circulation should prove inadequate to move a large mass of crystals.
  • compressed air can be introduced into ascending conduit 4 to promote circulation, as', for example, when heat supply is low in consequence of operating at less than full capacity.
  • liquid is introduced into the system until the volume of the liquid adequately covers the bottom of inlet tube 3 and 4 so that there is prevented a breakthrough of the gases of the gas space in chamber 2 when the liquid level is raised in chamber 1.
  • the volume in chamber 2 is adequate to compensate initially for the volume occupied during operation in conduits 3, 4, heater 5 and chamber 1 and still prevent the gas of chamber 2 from entering the inlet tubes.
  • Fresh solution is fed to the system but only in such amount so that the pressure differential increases till it reaches the desired final value P P When this is reached, more fresh so lution is supplied to maintain level H, constant, at constant pressure difference P P, until the desired level height in chamber 2 is reached.
  • the values which are realized then represent the condition at the end of the charge; the crystallization suspension has the desired specific gravity.
  • the products can be separated or the process operated on a continuous basis.
  • a predetermined concentration denoted by a particular preselected fixed value of specific gravity can be maintained as follows.
  • the capacity of this apparatus is determined and regulated at a constant level difference H, H by feeding a constant volume of fresh solution. Controlled by the second level regulator connected to chamber 2, enough material is withdrawn from outlet 9 so that level H and thereby the operating volume are kept constant. As the specific gravity increases, the pressure in gas space of chamber 2 is raised (through valve 11) so that the level H, of the liquid in chamber 1 be maintained at the preselected level; a higher pressure difference P, P, is thus established. This variation is detected by control device 15 and indicates the rise in specific gravity of the solution.
  • Pressure differences P P can be detected by means of the differential pressure measuring device 15, which regulates the heat supply to heat exchanger 5.
  • the pressure differential in itself is dependent on the position of valves 11 and 12.
  • Liquid level H is controlled by level regulator 13 which is maintained constant by the operation of this regulator on pressure regulator 14.
  • Level H is also maintained constant and is regulated by a separate level regulator connected to chamber 2 which, as described above, actuates outlet 9.
  • the fresh raw liquid which is fed to the upper and/or lower desired chamber is preferably pre-heated to the operating temperature of the apparatus.
  • these temperatures range from about l5 to about 120 C and especially 30 to 60 C, which then also correspond to the operating temperature.
  • higher temperatures may also be used, for instance for non-aqueous solutions, of the material to be crystallized.
  • the particular desired temperature depends in .general on the concentration of the raw material fed to the selected chamber, the solubility of the solid to be crystallized out thereof, the boiling point of the solvent (which is a practical upper operating limit of the process) and other similar factors.
  • the upper concentration of the raw material fed is determined by the saturation point of the solid to be crystallized out at the prevailing temperature.
  • the concentration of the solid is usually adjusted to values best suited under the circumstances. Commonly, the concentration is from about 25 to about 90%; it being 25 to 70% for citric acid.
  • Vacuum zone 1 is maintained at a pressure below atmospheric, which is in general determined by the desired crystallization temperature. The pressure is generally in the range of about 10 to 760 Torr, for aqueous solutions, specially at about 20 to 55 Torr.
  • the vacuum and the crystallization zones are illustrated as being in two different horizontal planes. But this is not a requirement of the apparatus or process of the invention.
  • the containers or cham bers can be positioned on the same or substantially same plane providing that there prevails an adequate level differential between the liquids in the respective chambers.
  • the vertical separation between chambers l and 2 is relative to the vacuum in chamber 1, the gas pressure in chamber 2 and from the specific gravity of the crystallization suspension.
  • a heating zone as such need not actually be part of the apparatus or process of the invention as long as the liquid which is supplied to the system is at a temperature high enough to cause vaporization of the solvent when introduced into the vacuum zone.
  • heating zone 5 there may be provided a suitable inlet for liquid at high temperature, high enough that when fed into the vacuum zone it will vaporize the solvent as described above. Any suitable energy means to change the liquid to vapor is suitable.
  • the crystallization product can be removed from the chamber continuously or intermittently.
  • the process of the invention is well-suited for fractional crystallization where a series of these crystalliza tion and vacuum chambers may be coupled in series and thereby achieving a sequential crystallization from liquids containing more than one particular solid.
  • the liquid from chamber 2 once it has been substantially freed from the first solid material, is then passed onto another chamber 2 which is then connected to a system similar to the one described above.
  • the system of the present invention lends itself admirably to the separation of one solid as a crystal from the liquid, and then continuing the process for the separation of the second crystal.
  • the crystallization chamber can be maintained at either atmospheric pressure or under a positive pressure. What is necessary is that there be established a differential in pressure between the gas space of the crystallization chamber and the vacuum chambers. It is preferable that the pressure in the crystallization chamber be at least atmospheric pressure.
  • the invention is illustrated by the following illustrative example, which is non-limiting.
  • the process is operated with a solution of citric acid, the operating parameters are as follows.
  • the pressure and vacuum are, respectively: P 1.25 ata and P 55 Torr Hence P 1.25 ata 12.5 meter (water column height) P 55 Torr 0.75 meter (water column height)
  • the crystallization suspension of citric acid has a specific gravity of y 1.4
  • the versatility of the apparatus acid process is noteworthy in as much as it is operative at varying ranges of pressures, both super-atmospheric in the crystallization chamber and under atmospheric in chamber 1. It is generally desired to maintain the crystallization chamber at a pressure slightly above atmospheric, as in the range of about 1.0 to about 2.0 ata, dependant of the specific gravity of the solution and the difference between the levels in the two chambers. The difference in levels of the two liquids is also dependent not only on the differential pressures in the air spaces in the respective chambers, but also on the specific gravity of the liquid to be crystallized, during the process and at the saturation point the crystals. When the process is operated to crystallize other chemicals having respective values, the pressures and vacuum, and/or the level differentials are adjusted accordingly.
  • agitation means 6 which is now represented as a stirrer
  • suitable means agitation or stirring means effective to keep the crystals in suspen sion such as air bubbling.
  • Chamber 2 can be opened and operated to atmo spheric pressure and during all or part of the process; in that case the level in vacuum chamber 1 is given by the vacuum thereat and by the specific gravity of the suspension.
  • the process of the invention is operative with any liquid from which it is desired to crystallize a solid. It is specially useful in the crystallization of organic acids including hydroxy-substituted organic acids, traditionally obtained from fermentations, like itaconic, fumaric, gluconic, citric acids. and their soluble salts es pecially the alkali metal salts such as sodium, potassium, ammonium and the like.
  • the crystalls obtained by the process of apparaties are wellformed crystals which, unlike the prior art products, remain in the original form when and as formed, with minimum breakage or physical attrition.
  • the crystals of the invention are well-developed, they are substantially free of smaller crystals and the greatest majority of the crystals are larger crystals rather than smaller crystals.
  • a crystallization apparatus for a liquid containing a material in solution comprising;
  • first and second conduit means connecting said chambers, and said liquid partially filling each of said chambers and circulating from said vacuum to said crystallization chamber through said first conduit means and from said crystallization to said vacuum chamber through said second conduit means;
  • said crystallization chamber having means adapted to control the liquid level in said crystallization chamber relative to the liquid level in the vacuum chamber said last-named means being adapted with pressure means controlling the pressure in said crystallization chamber above atmospheric thereby controlling the liquid levels in the crystallization chamber and the vacuum chamber at predetermined levels with respect to each other; said levels being adjusted when required by changes in the density of the liquid being crystallized; and
  • said bubble causing means comprises heating means for vaporizing a portion of the solution flowing through said second conduit means.
  • a crystallization apparatus for a liquid containing a material in solution to be crystallized comprising;
  • first and second conduit means connecting said chambers, said chambers being adapted to be partially filled by the liquid and said first conduit means being adapted for circulation for the liquid circulation of the liquid from said crystallization to said vacuum chamber;
  • said crystallization chamber being adapted with pressure means controlling the pressure in said crystallization chamber above atmospheric thereby controlling the liquid levels in the crystallization chamber and the vacuum chamber at predetermined levels with respect to each other; said levels being adjusted when required by changes in the density of the liquid being crystallized; and
  • heating means for promoting in said second conduit means the flow of vapor bubbles of said solution toward said vacuum chamber.
  • the apparatus of claim 12 which is adapted to be operated at constant temperature by adjustment of the pressure means of the crystallization chamber and the pressure means of the vacuum chamber while the spe cific gravity of the liquid increases.
  • the apparatus of claiim 12 which is adapted to be operated to maintain a constant specific gravity by ad justment of the pressure means of the crystallization chamber and the pressure means of the vacuum chamber while different crystallization temperatures are established.
US280928A 1972-08-15 1972-08-15 Crystallization apparatus having pressure-liquid level control means Expired - Lifetime US3859052A (en)

Priority Applications (11)

Application Number Priority Date Filing Date Title
US280928A US3859052A (en) 1972-08-15 1972-08-15 Crystallization apparatus having pressure-liquid level control means
DE2326753A DE2326753A1 (de) 1972-08-15 1973-05-25 Verfahren und vorrichtung zum kristallisieren von zum zusammenbacken neigenden stoffen
IT25276/73A IT989085B (it) 1972-08-15 1973-06-12 Processo e apparecchio per la cristallizzazione di sostanze tendenti ad agglomerarsi
JP48080002A JPS4958080A (ja) 1972-08-15 1973-07-17
IL42815A IL42815A (en) 1972-08-15 1973-07-24 Method and apparatus for crystallization
IE1285/73A IE37955B1 (en) 1972-08-15 1973-07-27 Crystallization apparatus
FR7329518A FR2196183B1 (ja) 1972-08-15 1973-08-13
NL7311196A NL7311196A (ja) 1972-08-15 1973-08-14
BE134557A BE803588A (fr) 1972-08-15 1973-08-14 Procede et installation de cristallisation
GB3858973A GB1447281A (en) 1972-08-15 1973-08-15 Crystallization apparatus
BR6287/73A BR7306287D0 (pt) 1972-08-15 1973-08-15 Processo e dispositivo para cristalizador de substancias contidas em solucoes

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US280928A US3859052A (en) 1972-08-15 1972-08-15 Crystallization apparatus having pressure-liquid level control means

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US (1) US3859052A (ja)
JP (1) JPS4958080A (ja)
BE (1) BE803588A (ja)
BR (1) BR7306287D0 (ja)
DE (1) DE2326753A1 (ja)
FR (1) FR2196183B1 (ja)
GB (1) GB1447281A (ja)
IE (1) IE37955B1 (ja)
IL (1) IL42815A (ja)
IT (1) IT989085B (ja)
NL (1) NL7311196A (ja)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4117978A (en) * 1976-01-29 1978-10-03 Ruthner Industrieanlagen-Aktiengesellschaft System for feeding solutions and suspensions
US4913771A (en) * 1988-11-25 1990-04-03 Mcintyre Glover C Method for dewatering sludge or slurry
US5700435A (en) * 1994-12-08 1997-12-23 Sulzer Chemtech Ag Method and apparatus for separating a substance from a liquid mixture by fractional crystallization
US20050000108A1 (en) * 2003-07-02 2005-01-06 Ragnarsson Anders T. Sludge dryer
CN102407030A (zh) * 2011-10-24 2012-04-11 张吉浩 味精常压结晶方法
CN109646974A (zh) * 2017-10-10 2019-04-19 中国石油化工股份有限公司 一种生产氰化钠的蒸发结晶装置和方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4119505A1 (fr) * 2021-07-16 2023-01-18 Hydromecanique Et Frottement Procédé de traitement d'un fluide comportant des sels et installation pour mettre en oeuvre le procédé

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US1831121A (en) * 1930-01-23 1931-11-10 Buffalo Foundry & Machine Comp Evaporating apparatus
US1879445A (en) * 1931-01-19 1932-09-27 Eastman Kodak Co Process of crystallizing salts from solutions containing them
US1976936A (en) * 1930-05-09 1934-10-16 Dorr Co Inc Method of crystallization
US2042661A (en) * 1931-11-06 1936-06-02 Krystal As Crystallization apparatus
US2819154A (en) * 1953-12-11 1958-01-07 Foster Wheeler Corp Apparatus for producing crystalline materials
US2876182A (en) * 1952-06-21 1959-03-03 Int Salt Co Method and apparatus for treating salts
US3467162A (en) * 1966-07-11 1969-09-16 Charles W Putnam Process of making concentrated phosphoric acid of improved clarity characteristics
US3514263A (en) * 1969-06-23 1970-05-26 Jan Michal Malek Fluidized bed crystallization device
US3518061A (en) * 1966-03-29 1970-06-30 Francois Laurenty Installations for crystallization of a substance in solution,especially anhydrous sodium sulfate
US3585237A (en) * 1966-09-29 1971-06-15 Wellman Lord Inc Crystallization of urea

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Publication number Priority date Publication date Assignee Title
NL215480A (ja) * 1956-07-03
FR1393567A (fr) * 1964-02-14 1965-03-26 Procédé et dispositif de concentration-cristallisation en continu des solutions liquides telles que les sirops sucrés
FR1567872A (fr) * 1967-07-11 1969-05-23 Institut Francais Du Petrole Cristalliseur

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1831121A (en) * 1930-01-23 1931-11-10 Buffalo Foundry & Machine Comp Evaporating apparatus
US1976936A (en) * 1930-05-09 1934-10-16 Dorr Co Inc Method of crystallization
US1879445A (en) * 1931-01-19 1932-09-27 Eastman Kodak Co Process of crystallizing salts from solutions containing them
US2042661A (en) * 1931-11-06 1936-06-02 Krystal As Crystallization apparatus
US2876182A (en) * 1952-06-21 1959-03-03 Int Salt Co Method and apparatus for treating salts
US2819154A (en) * 1953-12-11 1958-01-07 Foster Wheeler Corp Apparatus for producing crystalline materials
US3518061A (en) * 1966-03-29 1970-06-30 Francois Laurenty Installations for crystallization of a substance in solution,especially anhydrous sodium sulfate
US3467162A (en) * 1966-07-11 1969-09-16 Charles W Putnam Process of making concentrated phosphoric acid of improved clarity characteristics
US3585237A (en) * 1966-09-29 1971-06-15 Wellman Lord Inc Crystallization of urea
US3514263A (en) * 1969-06-23 1970-05-26 Jan Michal Malek Fluidized bed crystallization device

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4117978A (en) * 1976-01-29 1978-10-03 Ruthner Industrieanlagen-Aktiengesellschaft System for feeding solutions and suspensions
US4913771A (en) * 1988-11-25 1990-04-03 Mcintyre Glover C Method for dewatering sludge or slurry
US5700435A (en) * 1994-12-08 1997-12-23 Sulzer Chemtech Ag Method and apparatus for separating a substance from a liquid mixture by fractional crystallization
US20050000108A1 (en) * 2003-07-02 2005-01-06 Ragnarsson Anders T. Sludge dryer
US6892471B2 (en) 2003-07-02 2005-05-17 Anders T. Ragnarsson Sludge dryer
CN102407030A (zh) * 2011-10-24 2012-04-11 张吉浩 味精常压结晶方法
CN109646974A (zh) * 2017-10-10 2019-04-19 中国石油化工股份有限公司 一种生产氰化钠的蒸发结晶装置和方法

Also Published As

Publication number Publication date
GB1447281A (en) 1976-08-25
FR2196183B1 (ja) 1977-09-09
IE37955L (en) 1974-02-15
BR7306287D0 (pt) 1974-07-18
DE2326753A1 (de) 1974-02-28
JPS4958080A (ja) 1974-06-05
IT989085B (it) 1975-05-20
IE37955B1 (en) 1977-11-23
NL7311196A (ja) 1974-02-19
IL42815A0 (en) 1973-10-25
BE803588A (fr) 1973-12-03
FR2196183A1 (ja) 1974-03-15
IL42815A (en) 1976-10-31

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