US2987380A - Apparatus for handling and storage of slurries - Google Patents

Description

June 1961 c. c. BRUMBAUGH EIAL 2,987,380

APPARATUS FOR HANDLING AND STORAGE OF SLURRIES Filed July 21, 1954 r 3 Sheets-Sheet 1 FIG I INVENTORS CHESTER C. BRUMBAUGH JOHN E. VENABLE ATTORNEY J1me 1961 c. c. BRUMBAUGH EIAL 2,987,380

APPARATUS FOR HANDLING AND STORAGE 0F SLURRIES Filed July 21, 1954 5 Sheets-Sheet 2 INVENTORS E CHESTER C. BRUMBAUGH JOHN E. VENABLE ATTORNEY APPARATUS FOR HANDLING AND STORAGE OF SLURRIES Filed July 21, 1954 June 1951 c. c. BRUMBAUGH ETAL 3 Sheets-Sheet 5 lfill -l-lnll llull-U llll lllll Ii lfll llhn hl llnlil lll lll ll M t- I FIG. I

36 1NVENTOR$ CHESTER C. BRUMBAUGH FIG-m JOHN E. VENABLE ATTORNEY United States Patent 2,987,380 APPARATUS FOR HANDLING AND STORAGE OF SLURRIES Chester C. Brumbaugh, Painesville, and John E. Venahle, Madison, Ohio, assignors to Diamond Alkali Company, Cleveland, Ohio, a corporation of Delaware Filed July 21, 1954, Ser. No. 444,786 2 Claims. (Cl. 23-272) This invention relates to handling and storage of slurries of soluble salts, and more particularly relates to handling and storage of slurries of soluble salts and the recovery of a saturated solution of the slurried salt for further processing and use. The apparatus of the in vention is especially advantageous for the handling and storage of slurries of water-soluble salts of low bulk density, and for the recovery of saturated solutions of the salts from their slurries.

It has long been realized that the handling and storage of soluble salts as slurries has very definite advantages, particularly at the situs of the use of such salts in the form of their solutions, and especially salts of low bulk density, in that by handling and storing such salts in the form of slurries, the user is able to obtain a greater weight of salt per unit volume than could be obtained if the salt were retained in its dry state. Various types of apparatus have heretofore been proposed for handling and storing slurries of soluble salts at the situs of their use as concentrated solutions thereof. One common fault with these prior art apparatus, however, is that the amount of salt recovered as a solution thereof from the storing and handling facilities has been comparatively low, i.e., less than 85% of the salt fed to the handling and storage apparatus being recovered as a saturated solution in terms of the amount passing therethrough. This is especially true where the salt to be used forms a compound with the solvent, for example, where the salt forms a hydrate, and such hydrated salt tends to agglomerate and form large solid masses which are comparatively diflicult to dissolve and, because of their size, are not readily agitated to aid solution.

One of the objects of the present invention is to provide an apparatus for the storage and handling of slurries of soluble salts, in which apparatus a slurry of salt may be subjected to agitation as desired, and substantially 100% recovery of dissolved salt is effected.

Another object of the invention is to provide an apparatus for the storage and handling of slurries of soluble salts, in which apparatus a fluid stream, which may be a solvent or a non-solvent for the salt, either in its liquid or vapor form, or a mixture of liquid or vapor with air or other suitable gas, is introduced into the vessel containing the slurried salt in a downward direction near the bottom of the containing vessel in a region of high concentration of solution and slurried salt.

Another object of the invention is to provide a method of agitating liquid-solid slurries.

Another object of the invention is to provide a method of storing and handling a slurry of soluble salt and recovering a substantially saturated solution of the salt from the slurry.

Still another object of the invention is to provide an apparatus for the storing and handling of slurries of soluble salts, in which apparatus the means adapted to withdraw the salt solution from the containing vessel is maintained in position beneath the liquid level in the vessel.

A further object of the invention is to provide an apparatus for the storage and handling of slurries of soluble salts, in which apparatus the said means for introducing the fluid stream into the slurry are provided with nonclogging, self cleaning, check valves, which provide uniice directional flow of fluid into the slurry and direct said fluid stream away from the surface of said slurry.

These and other objects will be apparent to those skilled in the art from the description of the apparatus of the invention set forth hereinbelow.

Pursuant to these objects, the present invention pro-- vides considerable advantage over prior art apparatus and methods for the storage and handling of a slurry of soluble salt in a combination of means including a containing vessel, means near the bottom of said vessel for introducing a fluid stream, which may comprise the solvent either as a liquid or a vapor, in a downward direction into said vessel toward the bottom thereof, and means adapted to withdraw a solution of the salt from below the surface of liquid in said vessel, said means for withdrawing the solution from said vessel preferably being maintained below the level of solution within said vessel and above the slurry.

The present invention is described hereinafter in con junction with the drawings attached hereto and made a part hereof, wherein,

FIG. I is a cross-section of an apparatus designed in accordance with the principles of the present invention, for the storing and handling of a slurry of soluble salt, with auxiliary apparatus for introducing a slurry of soluble salt into the tank,

FIG. 11 is a detail, with parts broken away, of a conduit for withdrawing solution from the tank,

FIG. III is a plan view from above of means for supporting the conduit of FIG. II immediately below the surface of the liquid in the tank of FIG. I,

FIG. IV is an elevational view of the supporting means as shown in FIG. I11,

FIG. V is a plan view of the bottom of the tank of FIG. 1 from above, showing an arrangement of the means for introducing a fluid stream into a slurry of salt within the tank, and,

FIG. VI is a detail of a nozzle and check valve means for introducing a fluid stream near the bottom of the tank as shown in FIGS. I and V.

Referring now to the drawings, tank or vessel 2 is adapted to contain a slurry 4 of soluble salt, such as a slurry of hydrated sodium carbonate (soda ash) in a saturated solution thereof, and an overlaying layer of solution 6. The tank 2 may be mounted on any suitable support as shown. Means 8, shown in elevation in FIG. I, is provided for introducing a slurry of soluble salt into the tank 2 and may be any instrumentality suitable to convey a slurry of soluble salt to the tank 2.

As shown in FIG. I, a slurry 4 of soluble salt may be maintained in the tank 2 below a layer of clear solution 6, which is suitably a substantially saturated solution of the soluble salt. The solution 6, the level of which is indicated at 10, is withdrawn from tank 2 through opening 22 of conduit .12, shown in elevation in FIG. 1. Conduit 12 may be swiveled as at 14, or may be fashioned of flexible tubing, and is attached to any suit-able instrumentality, such as a float 16, also shown in elevation in FIG. I, which will maintain the opening 22 immediately below the level 10 of the surface of solution layer 6. Float 16 is suitably attached to the terminus of conduit 12 by means of flange 18 and rod 20.

The design of float 16 may take several equivalent forms, one form, illustrating the principle of this feature of the invention, being that shown in FIGS. III and IV. In the apparatus of FIGS. III and IV, two hollow chambers 16a and 16b, having suflicient displacement to support conduit 12 in the desired position with respect to the liquid level 10, are attached to base plate, or baflle 24, and to rod 20 by means of plates 26 and 28. Thus, the two chambers 16a and 16b, together with base plate, or bafile 24, form a channel within which the open end 22 Patented June 6, 1961 assaseo of conduit 12 is maintained, whereby the apparatus serves several functions simultaneously.

One of these functions is that of a skimmer in which solution is withdrawn from the tank beneath, but not at, the liquid level, and contamination of the solution withdrawn, by foreign substances floating on the liquid, is prevented. Another function is to prevent vortex formation in the solution at and near the opening 22 of conduit 12, which vortex formation causes air to enter the opening 22 of conduit 12, thereby decreasing considerably the volume rate of solution removal. This vortex formation is prevented by means of the channel formed by the combination of base plate, or baffle 24, and the chambers 16a and 16b, in which channel solution flows in comparatively shallow streams from opposite directions toward the opening 22. Base plate, or bafiie 24, serves the further function of preventing solids, in the body of slurry 4, from being sucked into conduit 12 as the float 16 approaches the level of the slurry.

Thus, the combination of float 16 and conduit 12 provides eificient means for withdrawing solution from the tank at a high volume rate, and preventing vortex formation at the point of take-off of solution from the tank, without the danger of carry-over of slurry solids.

Near the bottom of the tank 2, a header line 30, attached to any suitable means for supplying a fluid stream thereto, is provided with branch lines 32, to which branch lines 32 nozzles 34 are attached. Nozzles 34, only four of which are shown in position for illustrative purposes in FIG. V, are of tubular construction, and are attached to branch lines 32 in such a manner that the stream of fluid entering the nozzles 34 may be directed horizontally, or downwardly toward the bottom of the tank, preferably as shown in FIG. I. The tubular bodies of nozzles 34 have a closed end 36 and, near the closed end 36, one or more perforations or orifices 38, through which fluid material entering the nozzles may be discharged into the body of slurried solid 4.

The arrangement of the nozzles 34 along branch lines 32, in accordance with the present invention, should be such that the fluid streams issuing from nozzles 34, are directed away from the surface of the body of slurry 4, and are not directed vertically upwardly toward this surface. One of the reasons for prescribing this arrangement is that, under the condition of an initial upward direction of the fluid streams, there is considerable danger of disturbing the surface of the body of slurry to the extent that the layer of clear solution above the slurry is destroyed and slurry solids may be carried over into processing equipment. This is particularly true when the apparatus is operated continuously with respect to dissolving slurried solids and recovering a saturated solution of such solids.

A rather wide latitude in the directional arrangement of the nozzles 34 is permitted in accordance with the inventlon, ranging from substantially horizontally to vertically downwardly, i.e., in terms of angles, substantially from 180 to 360, or at any angle within the third or fourth quadrant, in terms of trigonometric functions. The important factor here is to arrange the nozzles so that the fluid streams issuing therefrom are not initially forced vertically upwardly toward, but away from, the surface of the body of slurry, so as to impinge either generally horizontally on the body of slurry, and somewhat on the side walls of the tank, or more vertically downwardly toward the bottom of the tank.

Positioning the nozzles so that the fluid streams are directed substantially vertically downwardly, to impinge upon the bottom of the tank, is preferred for two reasons: first, by this arrangement the nozzles 34 may be made to support the Christmas tree formed by header line 30 and branch lines 32; and secondly, by directing the streams vertically downwardly, there is the least possibility of causing undue turbulence in the upper portion of the body of slurry, which turbulence could cause carry-over of slurried solids into the pumping mechanism.

Referring to FIG. VI, suitable non-clogging, self cleaning, check valving means, such as rubber sleeve 40, held in place by securing means 42 close the orifices 33, in body of nozzles 34, in such a manner, that there is a uni directional flow of fluid through the nozzles into the slurry contained within the tank; when the pressure upon the fluid. flowing through the nozzles is released, the rubber sleeve 40, or its equivalent functioning as a check valve, prevents the solution or slurry contained within the tank from entering the nozzles 34.

Moreover, by this design of the nozzles 34, and their arrangement along the branch lines 32, as shown in FIGS. I and V, the fluid streams from the nozzles may be made to flow downwardly toward the bottom of the tank, and then are deflected outwardly through the body of slurry 4, thereby creating a comparatively large area of mild turbulence at the bottom of the body of slurry, around each nozzle, to aid in dissolving the slurried salt, with the result that the recovered solution is substantially saturated, free from solids from the slurry, and of constant composition. Also, these areas of turbu lence may be made to overlap by adjusting the rate of flow of solvent and the distance between adjacent nozzles, thereby preventing localized dissolving or agitation, and channeling, within the bed of slurried salt, which channeling results when streams of solvent are directed vertically upwardly away from the bottom of the tank. An undesirable effect of channeling resulting from thus directing the streams of solvent vertically upwardly is that the localized dissolving and agitation may cause wide variations in the composition of the solution recovered, and leave behind a heel of comparatively large mounds of undissolved salt for a considerable distance above the bottom of the tank. Thus, the uniformity of the composition of the solution recovered, and especially in semicontinuous or batch operations, the amount of salt recovered as a solution from the tank, in terms of the amount of salt in the tank, is appreciably less than with the apparatus of the present invention.

Moreover, with the streams of fluid directed vertically upwardly toward the top of the tank, a much lower rate of input of solvent must be used if carry-over of undissolved salt is to be avoided. Any undissolved salt passing with the solution through conduit 12 to pump 44 is undesirable for process use, would deposit in pipelines and valves, and could cause severe damage to the internal mechanism of the pump.

A further advantage of the apparatus and method of the present invention arises out of the combination of elements incorporated in the nozzles 34 and the floating solution-withdrawal means comprising conduit 12 and float 16. The nozzles 34 providing a downward com ponent in the direction taken by the stream of fluid introduced into the body of slurry permit a comparatively high flow rate of fluid into the slurry without producing undue turbulence in the region between the body of of clear solution and slurry, which turbulence could result in solids carry-over to pump 44 and, as noted above, cause severe damage; however, in order to take advantage of this means of providing a higher solution production rate in the dissolving operation, there must also be provided a suitable means for withdrawing solution from the tank at nearly the same rate at which it is formed. 'The present invention provides such a means in the combination of the conduit 12 and float 16 as noted above.

In operating the apparatus of the present invention, initially a slurry of soluble salt, in a saturated solution thereof, is introduced into tank 2, for example, a slurry of hydrated sodium carbonate (soda ash) in a saturated aqueous solution thereof, by a suitable means 8, and when the'desired amount of slurry has been introduced into the tank, the solids are allowed to, settle to provide a layer of clear solution above the solids. The solution of salt is withdrawn from the tank through conduit 12, and auxiliary equipment by any suitable means, such as pump 44 in conjunction with valves 46, 48, 50, and 52, to direct the solution to further processing and handling. Also, the solution may be used to provide further amounts of slurry in the tank, as by a slurry forming apparatus, such as means 8 in conjunction with vacuum pump 54.

In batchwise operation, as the level 10 approaches the level of the slurry in the tank, withdrawl of solution may be stopped, and solvent, either as a liquid or vapor, or a mixture of liquid or vapor with air or other suitable gas, may be introduced into the slurry near the bottom of the tank through header line 30, branch lines 32 and nozzles 34. The flow of fluid through the nozzles may be stopped as soon as the desired volume within the tank has been regained, whereupon the rubber sleeves 34 function as check valves to prevent the entry of slurry or solution into the nozzles 34 and thus into branch lines 32 and header line 30. After agitation of the slurry has ceased and the solids have settled sufliciently, further quantities of solution may then be withdrawn from the tank as previously described.

It is apparent from the description hereinabove that the apparatus may advantageously be operated continuously both with respect to the addition of solvent to the tank and the removal of solution therefrom, or the apparatus may be operated batchwise with respect to either the addition of solvent to the tank, or the removal of solution therefrom. That is to say, the volume rate of flow of solvent into the tank may intermittently be greater than volume rate of take-off of solution, during the dissolving operation.

It will be appreciated by those skilled in the art that in introducing fluid, as a gas or a liquid, into the slurry through nozzles '34, the temperature of the fluid may have a substantial eflect upon the physical form which the suspended particles in the slurry may take. Thus, for example, when the salt suspended in the slurry is sodium carbonate, and the solvent is water, it is desirable that the water introduced be at a temperature such that the temperature of the body of slurry is not lowered to a point below the transition temperature of sodium carbonate monohydrate to the higher hydrates of sodium carbonate, and that the temperature of the body of slurry be maintained above this temperature, and preferably below the temperature at which anhydrous sodium carbonate is formed, in order that the troublesome formation of large aggregate crystal masses of the hydrates of sodium carbonate may be prevented. However, if the temperature of the crystal slurry should fall below this transition temperature, the apparatus of the present invention permits the introduction of air, steam, or a mixture of steam and air, or other gas, into the slurry in such a manner that the crystal aggregates are readily agitated and reduced to finer particles of the monohydrate, whereby substantially complete recovery of the salt may readily be obtained without the necessity for hand labor or auxiliary mechanical equipment.

While there have been described various embodiments of the invention, the apparatus described is not intended to be understood as limiting the scope of the invention as it is realized that changes therewithin are possible and it is further intended that each element recited in any of the following claims is to be understood as referring to all equivalent elements for accomplishing substantially the same results in substantially the same or equivalent manner, it being intended to cover the invention broadly in whatever form its principle may be utilized.

What is claimed is:

1. An apparatus comprising a tank adapted to contain a slurry of a water-soluble salt, means to supply said slurry of salt in its water solution to said tank, means to cause said slurry in said tank to form an upper portion consisting essentially of said solution and a lower portion consisting essentially of a mixture of undissolved salt and said solution, a conduit for withdrawing said solution from said tank, said conduit opening into said tank at a level beneath the surface of said upper portion of solution and being attached to a float supported by said upper portion of solution, said float including a pair of hollow chambers arranged so as to form a channel therebetween and a baffle plate subjacent the opening of said conduit into said tank, and means adjacent the bottom of said tank for directing a plurality of streams of fluid generally downwardly in said mixture toward the bottom of said tank.

2. An apparatus comprising, in combination, a vessel adapted to contain a slurry of a water-soluble salt, means to supply a slurry of salt in a saturated solution thereof to said vessel, means to settle the solids of said slurry and provide a layer of clear solution in said vessel above said slurry, a conduit for withdrawing said solution from said vessel, said conduit having a terminus maintained beneath the liquid level in said vessel and attached to a float supported by said solution, said float being free to move in accordance with changes in the liquid level of said solution and including a pair of spacedapart hollow chambers mounted upon an imperforate base plate in such a manner as to form a horizontal channel within which the terminus of said conduit is positioned, and a plurality of nozzles near the bottom of said tank for directing a stream of fluid into said slurry outwardly and downwardly toward the bottom of said vessel, each of said nozzles comprising a closed end tubular body having a plurality of perforations near the closed end thereof and a flexible sleeve surrounding said body and covering said perforations.

References Cited in the file of this patent UNITED STATES PATENTS 384,306 Bourdil June 11, 1888 418,984 Parks Jan. 7, 1890 815,272 Devereux Mar. 13, 1906 860,775 Usher July 23, 1907 881,434 Moburg Mar. 10, 1908 949,455 Usher Feb. 15, 1910 2,608,300 Small Aug. 26, 1952 2,670,848 Van Houten et a1. Mar. 2, 1954

Claims (1)

1. AN APPARATUS COMPRISING A TANK ADAPTED TO CONTAIN A SLURRY OF A WATER-SOLUBLE SALT, MEANS TO SUPPLY SAID SLURRY OF SALT IN ITS WATER SOLUTION TO SAID TANK, MEANS TO CAUSE SAID SLURRY IN SAID TANK TO FORM AN UPPER PORTION CONSISTING ESSENTIALLY OF SAID SOLUTION AND A LOWER PORTION CONSISTING ESSENTIALLY OF A MIXTURE OF UNDISSOLVED SALT AND SAD SOLUTION, A CONDUIT FOR WITHDRAWING SAID SOLUTION FROM SAID TANK, SAID CONDUIT OPENING INTO SAID TANK AT A LEVEL BENEATH THE SURFACE OF SAID UPPER PORTION OF SOLUTION AND BEING ATTACHED TO A FLOAT SUPPORTED BY SAID UPPER PORTION OF SOLUTION, SAID FLOAT INCLUDING A PAIR OF HOLLOW CHAMBERS ARRANGED SO AS TO FORM A CHANNEL THEREBETWEEN AND A BAFFLE PLATE SUBJACENT THE OPENING OF SAID CONDUIT INTO SAID TANK, AND MEANS ADJACENT THE BOTTOM OF SAID TANK FOR DIRECTING A PLURALITY OF STREAMS OF FLUID GENERALLY DOWNWARDLY IN SAID MIXTURE TOWARD THE BOTTOM OF SAID TANK.

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