US3030296A - Apparatus for treating process streams - Google Patents

Description

April 17, 1962 3,030,296

R. L. M GLASSON ETAL APPARATUS FOR TREATING PROCESS STREAMS Original Filed Feb. 10, 1956 2 SheetsSheet 1 INVENTORS /?.L. McGLASSO/V F. J. RADD 0.4. SHOCK ATTORNEY April 17, 1962 R. M GLASSON ETAL 3,030,296

APPARATUS FOR TREATING PROCESS STREAMS Original Filed Feb. 10, 1956 2 Sheets-Sheet 2 A p I J l INVENTORS R. L. Ma GLASSOA/ F. J. RADD D.A.$HOCK mmmg ATTORNEY United States Patent This invention relates to an apparatus for altering the concentration of soluble materials in a pressurized fluid electrolyte without loss of pressure of the electrolyte.

It is well known that certain liquid and gas streams require addition or removal of various soluble materials in order to inhibit the corrosive efiects of such streams, or to otherwise prepare them for their desired use. For example, boiler feed water ordinarily contains dissolved oxygen which should be removed or inhibited prior to injection of the water into a boiler to reduce the corrosive action of the feed water. In accordance with present practices, dissolved oxygen is removed from a boiler system or treated in either of two different ways; by employment of chemicals to inhibit corrosive tendencies, or by electrolysis. The former method is expensive and diflicult to control. The latter is usually performed only when the water and the treating electrolyte are at relatively equal pressures. In practice, the feed water is usually diverted into a tank while oxygen is being removed. Such batch processing unduly retards the supply of boiler feed water and requires extensive equipment to accomplish electrolysis.

In other pressurized fluid systems it may not only be desirable to remove a soluble material from a fluid stream, but it may also be important to add other soluble materials to the stream. Currently, the two operations are carried out separately; either by chemical treatment or by batch processing.

Our invention contemplates a novel apparatus for treating a pressurized fluid, in which treatment is accomplished 4 Claims.

during continuance of fluid flow and without use of complex chemical processes. We contemplate an electrolytic apparatus capable of maintaining the pressure of the fluid stream without interruption of stream flow. Our apparatus is particularly useful in treating high pressure fluid streams in which it is desirable to retain the electrolyte used in electrolytic communication with the process stream at a low pressure as a result of which the electrolyte chamber may be economically constructed and may be opened for cleaning or recharging without the necessity of interrupting the main flow stream.

Our invention also contemplates an apparatus for dual treatment of a flowing stream; to permit removal of certain soluble materials and addition of other soluble materials to the stream in a single operation without interrupting stream flow.

An important object of our invention is to provide an improved apparatus for electrolytically treating a flowing stream without its interruption.

Another object of our invention is to furnish apparatus which will permit the treatment of pressurized fluids to inhibit corrosiveness without employment of expensive chemical inhibitors.

A more specific object is to provide apparatus for removing dissolved oxygen from an aqueous stream while the stream is under pressure, and, if desired, for introducing soluble materials thereto concomitantly with the removal of dissolved oxygen.

A further purpose of our invention is to provide simply 3,030,296 Patented Apr. 17, 1962 ice interposed in a pressurized fluid stream to alter the concentration of soluble materials therein without appreciably obstructing flow.

Still another object of our invention is to provide an apparatus for electrolyticaly treating a pressurized fluid in which the electrolyte may be recharged without the necessity of reducing the pressure of the fluid.

Other objects and advantages of the invention will be evident from the following detailed description as related to the accompanying drawings in which:

FIGURE 1 is an elevational view of one form of our novel apparatus, portions of the apparatus being shown in section to illustrate details of construction.

FIGURE 2 is a sectional view as taken along lines 22 of FIGURE 1.

FIGURE 3 is an elevational view of a modified apparatus with portions of the apparatus shown schematically.

Referring to the drawings in detail, and particularly FIGURE 1, a flow conduit 4, which conveys the fluid to be treated under pressure, has spaced, opposed flanges 6 and 8 for connection with our novel apparatus which is generally designated by reference character 10.

The treating apparatus 10 comprises a T type connector 12 having aligned and opposed flanged ends 14 and 16 of a size to mate with the flanges 6 and 8 respectively of flow conduit 4. Flange 1 6 is secured to its mating flange 8 by a plurality of spaced bolts 18, and an insulating washer or ring 20 is disposed between the flanges to prevent direct contact therebetween. Ring 20 also protrudes inwardly beyond the inner periphery of the T 12 for purposes later described. Each bolt 18 is surrounded by an insulating material 22, and an insulating washer 24 surrounds each bolt 18 adjacent its head and nut to retain the bolts 18 out of direct contact with the flanges 8 and 16. The flanges 6 and 14 are interconnected in a similar manner so that T 12 is electrically insulated from flow conduit 4.

An electrode 26 is secured in the T 12 between the washers 20. The electrode 26 comprises a plurality of elongated bars 28 (see also FIGURE 2) secured at their opposite ends in concentric rings 30 and 32. The outer rings 30 are of a size to contact the inner periphery of the T connector 12, and are secured to the complementary inner rings 32 by a plurality of circumferentially spaced straps or plates 34. In FIGURE 2 it will be observed that rods 28 are arranged in two concentric, circular patterns, when viewed in transverse cross section. Therefore, although a fluid flowing through the conduit 4 and T 12 will be effectively contacted by some portion of the electrode 26, the flow'of the fluid will not be appreciably obstructed. It will also be apparent that the electrode assembly 26 may be easily removed from T 12 for replacement or repair by disconnecting the T from the flow conduit 4.

The remaining flanged outlet 34 of the T 12 is secured to the mating flange 36 of a suitable hand-operated valve 38. Flanges 34 and 36 are separated by an insulating washer 40, and are interconnected by bolts 42 suitably insulated from the flanges in the same manner as previously described. It will thus be apparent that no electrical current can flow directly from the T 12 to the valve 38. The opposite flange 44 of valve 38 is bolted to the mating flange 46 of an electrolyte container or chamber 48.

The container 48 preferably comprises a short section 50 of tubular material having flange 46 connected to one end thereof and another flange 52 on the opposite end thereof. A further flange 54 mates with flange 52 and is secured on the lower end of an L-shaped tubular section 56. An annular shaped retaining plate 58 is interposed between the flanges 52 and 54. The plate 58 has a plurality of circumferentially spaced apertures through the plate 58. is imposed on the right hand side of the plate 64 (when of plate 58 to prevent bypass of fluids between the outer periphery of the plate 64 and the inner periphery of the It will also be observed that when a pressure viewed as shown in FIGURE/1) the plate 64 will be pressed against the lip or flange 62 and will not be forced out of the plate 58. The plate 64 has certain permeability and strength characteristics as will be more fully hereinafter set forth.

The upperend 66 of L-shaped section 56 is externally threaded to receive a cap member 68. An aperture 70 is formed vertically through the central portion of the cap '68 to loosely receive another electrode 72. The electrode 72 is preferably bar-shaped, and is separated from the walls of the'aperture 70 by a suitable insulating material 74. The upper end of electrode 72 protr udes from the aperture '70 and has a suitable connector 76 thereon for connection with a conductor 78. The connector 76 is insulated from cap 68 and provides the means for suspending the electrode 72 in the cap 68. Another and smaller aperture 80 is formed vertically through the cap'68 adjacent the aperture 70 and has a breather cap 82 secured in the upper end thereof. The breather cap 82 may be constructed in any suitable man- 'ner to provide a vent from the interior of the L-shaped section 56 and aperture 80 to the atmosphere.

Conductor 78 extends from connector 76 to the posielectrode 26. V

Electrodes 26 and 72 may be constructed of any suitablemateriaI, but preferably a 'material which is substantially insoluble in'either the fluid to be treated, or

1 the electrolyte, as will be more fully hereinafter set forth. Generally speaking, the electrodes 26 and 72 may be formed of steel.

Operation 'With the direct current source 84 arranged as shown in FIGURE 1, the apparatus may be conveniently used for removing dissolved oxygen from an aqueous electrolytic stream, such as a boiler feed water stream.

Assuming thatthe feed water is being conducted through the conduit 4, the section 56 of the container 48 is filled with an electrolytic solution of a salt, an acid, or a base,

but preferably a salt such as sodium chloride. The porosity'and resistance to flow of the porous plate or separator 64 are so selected as to substantially prevent flow of'the electrolyte into container section 50. When the valve 38 is opened, the boiler feed water will flow outwardly through the valve and into the section 50 of the container 48 into contact with the opposite side of porous plate 64. Ordinarily, the boiler feed water will be at a substantially higher pressure than the electrolyte in the container section 56, thereby retaining the plate 64 positively in contact with'the lip 62.

The plate 64 forms a contacting zone for the electrolyte I andthe fluid being treated, such that a current may be transferred between the electrolyte and the stream, and

lens may be exchanged through the plate 64. The plate 64 will have permeability characteristics such that the fluids will contact each other within the plate, yet neither of the fluids will migrate all the way through the plate to any appreciable'extent and 'mix with the opposite fluid. In addition, the. plate 64 is of'such strength as to prevent pressure diiferential'is imposed across'it.

' extent.

4. breakage or crumbling thereof when a substantial pres- In any event, the plate should be capable of withstanding a pressure difierential of 1 foot of water. Any porous material may be used for the plate 64,suchas porous aluminum oxide, porous silicon carbide or porous metal, providing it has the required permeability and strength characteristics as set forth'above. Amaterial which is exceptionally suited for this purpose is fritted glass which can be obtained commercially in variousdiameters and thicknesses I and which will withstand a pressure ditferential up to at least 150 pounds per square inch.

When the direct current source 84 is placed in operation, the electrode 26 becomes the cathode and the electrode 72 becomes the anode. As a result electrons migrate from the cathode'26' through the fluid being treated, the porous plate 64 and the electrolyte in the chamber 48 to the anode 72. Hydrogen ions simultaneously migrate from the electrolyte through the porous plate 64 and into the stream being treated toward the cathode 26. These hydrogen ions each acceptan electron at the cathode to form hydrogen atoms which react with the dissolved oxygen in the boiler feed water stream to form water, thereby rendering the dissolved oxygen inactive. Simultaneously, a portion of the oxygen will migrate through the porous plate 64 and the electrolyte to collect on the anode 72. This oxygen, along with the halide evolved from the electrolyte, is vented through the aperture and breather cap 82. However, theoxygen evolved at the anode 72 will be substantially inconsequential compared to the quantity of oxygen effectively removed from the stream by'reaction with hydrogen atoms to form water.

When the electrolyte is depleted, container 48 may be recharged by simply removing cap 68 from the upper end 66 of the section 56 and pouring a new charge of electrolyte into the section 56. The flow of the boiler feed water through thecondu'it 4 need not be interrupted 'whencontainer 48 is being recharged, since the water will not migrate through porous plate 64 to any appreciable It will also be apparent that more than one of thedevices 10 may be used, if necessary, to completely remove the dissolved oxygen from the boiler feed water. However, in this specific example it is preferred that only-one apparatus 10 be utilized.

-In' the event it is desired to replace the porous plate 64, the valve 38 may be closed, and the complete container'48 removed from the valve 38. It will again be notedthat flow through the conduit 4 need not be stopped for changing the porous plate 64.

To'illustrate the eifectiveness of our invention in removing dissolved'oxygen from an aqueous stream, the following test was run in the laboratory: A stream comprising a 3% aqueous solution of sodium chloride was first saturated With air, and then treated with an electrolyte, which was also a 3% solution of sodium chloride. The electrolyte and the stream being treated were separated by a fritted glass plate approximately one quarter of 'an inch thick. This fritted glass plate successfully maintained a pressure diflerential of approximately 2.5 pounds per square inch (6 ft. head of water) across the fritted glass Without any significant flow of the aqueous stream into the electrolyte chamber. The following data were obtained using various currents and voltages as noted:

Current P.p.m. of P.p.m. of

Voltage (Milll- Dissolved Dissolved 02 Re- OgRemalning moved From the foregoing data will be observed that from 0.48 ppm. to 7.79 ppm. of dissolved oxygen was removed from the aqueous stream. As is well known, the removal of dissolved oxygen to the latter extent substantially eliminates corrosivity of the aqueous stream.

The apparatus illustrated in FIGURES 1 and 2 is also adaptable for substantially an unlimited number of different treating operations. For example, with the direct current source 84 connected as shown, the apparatus may be utilized to remove such ions as fluorides, chromates, or dichromates from a process stream flowing through conduit 4. In that event, the various ions migrate from the T 12 through the porous plate 64 into the electrolyte and then to the anode 72.

As another example, a process stream may be treated with fluorine or chloride ions. In using our apparatus for such a purpose, the polarity of direct current source 84 is reversed to provide a flow of electrons from electrode 72 to electrode 26, and a solution of sodium chloride or sodium fluoride is used as the electrolyte in container 48. It will then be apparent that the fluorine or chloride ions will migrate from the electrolyte through porous plate 64 and then into the process stream flowing through conduit 4.

It will also be apparent that a pair of the devices 10 can be used to remove salts from hard water. In one apparatus 10, the polarity of a direct current source 84 can be arranged to remove anions such as Ca and Mg, and the second apparatus 10 arranged to remove such cations as chloride, sulfate and CO Another pressing need for similar treatments is in large scale water flooding operations in the oil industry where sea water is used as the flooding water. In such an operation it is desirable not only to remove dissolved oxygen from the treating water but also to add chlorine to the water for removing bacteria. The dissolved oxygen promotes steel corrosion in the wells through which the flooding water is introduced, and the bacteria in the flooding water induces plugging of the formation which receives the flooding water. The apparatus illustrated in FIGURE 3 is partcularly suited for the operation.

In FIGURE 3 reference character 10a generally designates an apparatus constructed in substantially the same manner as the apparatus 10 shown in FIGURE 1. The apparatus 10a is interposed in sea water flow conduit 94 and is insulated from conduit 94 in the same manner as previously described.

The apparatus 10a diifers from the previously described apparatus *10 in that vent aperture 89' at the upper end of the electrolyte chamber 48 receives one end of a conduit 96 instead of the breather cap 82 as previously described. The opposite end of conduit 96 is connected to the sea water flow conduit 94 down stream of the apparatus 10a to inject the soluble materials evolved from the electrolyte. Since electrolyte chamber 48 will be at a lower pressure than flow conduit 94, a suitable pump or compressor 97 is interposed in the conduit 96 to force the evolved soluble materials into conduit 94. In addition, a suitable valve 98 is provided in conduit 96 to stop the flow of materials through conduit 96 when and as desired. Conduit 96 is secured to the conduit 94 through use of a suitable insulated connector 100 which may be constructed in the same manner as the insulated joints previously described. A valved bleedolf line .102 may be interconnected to the conduit 96 if desired.

In operation of the apparatus 10a, section 56 of the electrolyte chamber 48 is filled with a suitable electrolyte, such as sodium chloride. Direct current source 84 is then activated to provide a flow of electrons from the cathode 26 through the sea water, the porous plate 64, and the electrolyte to the anode 72. As in the above description relating to the removal of dissolved oxygen, hydrogen ions will migrate from the electrolyte through the porous plate 64 into the sea water within the cathode 26 to accept electrons at the cathode to form hydrogen atoms which then react with the dissolved oxygen to form water.

Simultaneously, the chlorine evolved from the electrolyte in the chamber 48 is discharged through the aperture and conduit 96. The pump 97 forces the chlorine into the sea water down stream of the cathode 26 to effectively eliminate the harmful bacteria which may be contained in the sea water.

It will be apparent that the sea water passing through the cathode 26 and beyond the outlet end of the conduit 96 will have substantially all of the dissolved oxygen removed therefrom and will be efiectively treated with chlorine for bacterial control. The sea water will then be suitable for water flooding operations and the sea water will neither corrode the steel within the injection well nor plug the formation into which the sea water is injected.

From the foregoing it will be apparent that the present invention provides novel apparatus for treating fluid electrolytes under pressure, in which the treating electrolyte may be recharged without reducing the pressure of the fluid being treated. The apparatus of our invention is particularly useful in treating pressurized fluid streams where it is either desired to add soluble materials to the stream or to remove soluble materials therefrom without interrupting the flow. The use of expensive chemical inhibitors is not required and a stream may be treated in two different ways in a single operation.

While particular embodiments of the invention have been described, it will be understood, of course, that the invention is not limited thereto since many modifications may be made, and it is, therefore, contemplated to cover by the appended claims any such modifications as fall within the true spirit and scope of the invention.

This invention is a division of our application, Serial Number 564,663, filed February 10, 1956, now abandoned.

The invention having thus been described, what is claimed and desired to be secured by Letters Patent is:

1. Apparatus for treating a stream of pressurized fluid comprising: a first container for said fluid, said container consisting of a portion of the flow conduit for said stream; a second container for an electrolyte connected to said first container and having an opening therein for the removal of gases; a first electrode in said first container and electrically insulated from said flow conduit and from said second container; a second electrode in said second container and electrically insulated therefrom; a direct current source of power connected to said electrodes so that said first electrode is the cathode and said second electrode is the anode; and a porous plate made of fritted glass interposed between and separating said containers, said plate having such permeability and strength characteristics as to allow contact between fluids on either side of the plate but to resist breakage and prevent any appreciable migration of fluid therethrough during pressure ditferentials across said plate of from one foot of water up to at least pounds per square inch.

2. Apparatus for treating a stream of pressurized fluid comprising: a first container for said fluid, said container consisting of a portion of the flow conduit for said stream; a second container for an electrolyte connected to said first container and having an opening therein for the removal of gases; a first electrode in said first container and electrically insulated from said flow conduit and from said second container; a second electrode in said second container and electrically insulated therefrom; a direct current source of power connected to said electrodes so that said first electrode is the cathode and said second electrode is the anode; and a porous plate made of aluminum oxide interposed between and separating said containers, said plate having such permeability and strength characteristics as to allow contact between fluids on either side of the plate but to resist breakage and 7 prevent any appreciable migration of fluid therethrough during pressure difierentials across said plate of from one foot of Water up to at least 150 pounds per square inch.

3. Apparatus for treating a stream of pressurized fluid comprising: a first container for said fluid, said container consisting of a portion of the flow conduit for said stream; a second container for an electrolyte connected to said first container and having an opening therein for the removal of gases; a first electrode in said first container and electrically insulated from said flow conduit and from said second container; a second electrode in said second container and electrically insulated therefrom; a direct current source of power connected to said electrodes so that said first electrode is the cathode and said second electrode is the anode; and a porous plate made of silicon carbide interposed between and separating said containers, said plate having such permeability and strength characteristics as to allow contact between fluids on either side of the plate but to resist breakage and prevent any appreciable migration of fiuid therethrough during pressure difierentials across said plate of from one foot of water up to at least 150 pounds per square inch.

4. Apparatus for treating a stream of pressurized fluid comprising: a first container for said fluid, said container consisting of a portion of the flow conduit for said stream; a second container for an electrolyte connected to said first container and having an opening therein for the removal of gases; a first electrode in said first container and electrically insulated from said flow conduit and from said second container, said electrode comprising a plurality of elongated bars longitudinally disposed in said container and arranged substantially uniformly throughout the cross section thereof; a second electrode in said second container and electrically insulated therefrom; a direct current source of power connected to said electrodes so that said first electrode is the cathode and said second electrode is the anode; and a porous plate interposed between and separating said containers, said plate having such permeability and strength characteristics as to allow contact between fluids on either side of the plate but to resist breakage and prevent any appreciable migration of fluid therethrough during pressure differentials across said plate of from one foot of water up to at least 150 pounds per square inch.

References Cited in the file of this patent UNITED STATES PATENTS 1,012,808 Bull Dec. 26, 1911 1,246,099 Hullin Nov. 13, 1917 2,289,687 Stuart July 14, 1942 FOREIGN PATENTS 751,578 France June 19, 1933

Claims (1)

1. 4. APPARATUS FOR TREATING A STREAM OF PRESSURIZED FLUID COMPRISING: A FIRST CONTAINER FOR SAID FLUID, SAID CONTAINER A SECOND CONTAINER FOR AN ELECTROLYTE CONNECTED TO SAID FIRST CONTAINER AND HAVING AN OPENING THEREIN FOR THE REMOVAL OF GASES; A FRIST ELECTRODE IN SAID FIRST CONTAINER AND ELECTRICALLY INSULATED FROM SAID FLOW CONDUIT AND FROM SAID SECOND CONTAINER, SAID ELECTRODE COMPRISING A PLURALITY OF ELONGATED BARS LONGITUDINALLY DISPOSED IN SAID CONTAINER AND ARRANGED SUBSTANTIALLY UNIFORMLY THROUGHOUT THE CROSS SECTION THEREOF; A SECOND ELECTRODE IN SAID SECOND CONTAINER AND ELECTRICALLY INSULATED THEREFROM; A DIRECT CURRENT SOURCE OF POWER CONNECTED TO SAID ELECTRODES SO THAT SAID FIRST ELECTRODE IS THE CATHODE AND SAID SECOND ELECTRODE IS THE ANODE; AND A POROUS PLATE INTERPOSED BETWEEN AND SEPARATING SAID CONTAINERS, SAID PLATE HAVING SUCH PERMEABILITY AND STRENGTH CHARACTERISTICS AS TO ALLOW CONTACT BETWEEN FLUIDS ON EITHER SIDE OF THE PLATE BUT TO RESIST BREAKAGE AND PREVENT ANY APPRECIABLE MIGRATION OF FLUID THERETHROUGH DURING PRESSURE DIFFERENTIALS ACROSS SAID PLATE OF FROM ONE FOOT OF WATER UP TO AT LEAST 150 POUNDS PER SQUARE INCH.

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