US3512639A - Liquid filtration-mass transfer system - Google Patents

Description

May 19, 1970 I. J.- KUGELMAN EFAL 3,512,639

" LIQUID FILTRATION-MASS TRANSFER SYSTEM Filed 001;. 18, 1967 2 Sheets-Sheet 1 IA'WiNTORS Irwin J. Kugelmun Joseph B. Hellmann ZZM ATTORNEY May 19, 1970 I. J. KUGELMAN ETA!- 3,512,639

LIQUID FILTRATION-MASS TRANSFER SYSTEM 2 Sheets-Sheet 2 Filed Oct. 18, 1967 INVENTORS Irwin J. Kugelmun BY Joseph B. Hellmonn Fig. 2.

ATTORNEY United States Patent Ofice 3,512,639 Patented May 19, 1970 3,512,639 LIQUID FILTRATION-MASS TRANSFER SYSTEM Irwin Jay Kugelman, Union, N.J., and Joseph B. Hellmanu, Queens Village, Jamaica, N.Y., assignors to American Standard llnc., New York, N.Y., a corporation of Delaware Filed Oct. 18, 1967, Ser. No. 676,167 Int. Cl. BOld 33/20 US. Cl. 21080 23 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a method and apparatus for countercurrent contact between a liquid stream and a bed of solid particles for the purposes of removing components either from the liquid stream or from the solid particles. The invention is applicable to such processes as the treatment of sanitary or industrial wastes with powdered or granular coal, the treatment of water supplies by filtration through beds of granular sand, the softening of hard waters by means of particles of ion exchange resins, the decoloration of sugar solutions by means of activated carbon, the extraction of soybean oil with solvents, as well as other like processes which will be obvious to those skilled in the art.

The invention provides a method and apparatus wherein a bed of solid particles is maintained in a compact condition by essentially completely filling the vessel in which it is contained, in which method and apparatus the spent portion of the bed is periodically or intermittently removed by placing the bed of solid particles and the entrapped liquid under an absolute pressure such that the solid particles and any entrapped solids and liquid will issue forth when said particles are communicated with an external vessel at less than said pressure. The spent bed material is discharged from the lower surface of the bed. New bed material is then supplied to the upper surface of the bed. 1

CROSS REFERENCES TO RELATED APPLICATIONS Four other related patent applications, assigned to the same assignee and filed concurrently herewith are identifiled as follows: R. S. Bevans, SN 676,193, filed Oct. 18, 1957; 'R. S. Bevans, ISN 676,266, filed Oct. 18,1957; J. B. Hellmann, SN 676,180, filed Oct. 18, 1957; and I. I. Kugelman, SN 676,192, filed Oct. 18, 1957.

BACKGROUND OF THE INVENTION This invention is useful in various liquid treating applications, such as the treatment of sewage, industrial waste, and municipal water supplies.

The closest known prior art is US. Pats. 3,244,561 and 3,200,067.

SUMMARY The invention contemplates an improved counter-current apparatus and method for compacting and periodically or intermittently replenishing a solids-liquid contacting bed. Compaction is accomplished by essentially completely filling a vessel with solid particles. The bed is maintained continually serviceable by periodically removing and replenishing the solid particles or batches of the solid particles.

THE DRAWING FIG. 1 illustrates schematically a sectional view taken through a form of an apparatus embodying the invention.

FIG. 2 illustrates schematically a sectional view taken through a second form of an apparatus embodying the invention.

GENERAL DESCRIPTION In the drawing of FIG. 1, there is shown an upstand ing vessel including two main sections 10 and 40, each of which is tapered at both ends and these two sections are joined together by a valve 36. Both sections 10 and 40 contain granular coal or other appropriate material designated respectively 12 and 42. The section 10 may be regarded as the treatment section and section 40 as the charging section. Liquid influent, such as raw sewage or industrial waste, is fed into an inlet line 13, then raised in pressure by a pump 16 connected to a line 14, the line 14 having suitable perforations 18 within the treatment section 10, and the influent is delivered through the perforations 18 to the lower region of the bed 12 which is contained within the treatment section 10'. A valve 38 is inserted in line 14 and operated, whenever desired, to interrupt the supply of the influent liquid. An outlet line 26, which includes a valve 24, is coupled to the upper region of the section 10. The portion of line 26 encompassed within section 10 also has suitable perforations 22 to prevent any of the bed material 12 from entering line 26. The valve 24 within line 26 is operated periodically to interrupt the flow of the eflluent liquid from output.

intervals, fed through a line 44, then raised in pressure by a pump 46 and supplied by another line 48 to the top of the charging section 40. A valve 50 is shown coupling the charging section 40' to a storage hopper- 60. Valve 50 is operated intermittently to allow some of the solid particles, such as coal, to be supplied to the top of the charging section 40. Another valve 20 is located in the lowermost region of the treatment section 10 so that some of the bed material, particularly some or all of the portion which has become clogged or otherwise spent, may be removed intermittently and, if desired, delivered to another. station (not shown) where it may be regenerated for reuse in the column or disposed of or utilized for other purposes, for example, as a fuel. Valve 34 located below perforated line 14 may be periodically opened to remove liquid from vessel 10 to aid in bed compaction.

The reference characters T1, T2 and PS schematically represent a time factuator, a cycle-timer .and a pressure switch, respectively, which may be coupled in any well known manner to the controllable devices, such as pump 16 and valve 38, the valves 20, 36 and 34 and the thepump 46 and outlet control valve 24.

Detailed description of method of FIG. 1

Vessel 10 is initially essentially completely filled with the appropriate granular material, e.g. coal, with the and apparatus spaces between particles filled with liquid. Vessel 40 is initially filled either partially or completely with the ap propriate granular material with any space, which is unfilled by the granular material, filled with liquid. Under normal operating conditions, influent liquid, such asraw sewage, will be supplied through the line 13 and raised in pressure by pump 16 for transmission through line 14,

then through the perforations 18 in that line, into the With the valve 36 connecting the columnar sections and 40 closed and the outlet valve 24 open, liquid which has been filtered or treated in its travel vertically up through the bed 12 will enter the outlet line 26 through the perforations 22 therein and be discharged into the holding tank 28. The perforations 22 of the discharge pipe are appropriately screened to prevent bed particles or filtering material from escaping from the bed 12. The treated liquid is the desired end product, and it may be retained by tank 28 or in any other appropriate receptacle (not shown), or it may be discharged into a lake or river. The treated liquid product is continuously fed to the tank 28 except during the very brief periods of the surge cycles when clogged bed material is discharged.

The upfiowing liquid traversing the bed 12 exerts an upward drag force on the bed 12. This force will increase as the pore spaces become clogged by particles or solids extracted from the influent liquid. When the drag force exceeds the combined forces resulting from the buoyant bed weight of the bed 12 and from the friction due to the contact between the bed 12 and the wall of the treatment section 10, the bed will be caused to move up, that is, to be uplifted, or the spaces between particles will be caused to increase, i.e. the bed will be caused to be fluidized. However, the bed 12 is restrained from any ordinary movement or expansion within the treatment vessel 10 because the grandular particles essentially completely fill vessel 10. The bed 12 will instead be caused to compact. The additional compaction with the bed 12 will increase the filtration efficiency within the bed 12.

As the pore spaces of the bed become clogged with solids removed from the liquid, the discharge pressure of the pump 16 required to force the liquid through bed 12 will increase.

The pressure resulting from the clogging of the pore spaces may be allowed to increase up to but not exceeding the limit of the capacity of the pump 16, at which limit it will be necessary to remove the clogged layer or layers of the bed 12 from the vicinity of perforations 18 in order to reduce the influent pressure and permit the system to continue to function. It is one of the objects of the invention, as already noted, to periodically or intermittently remove from the vicinity of perforations 18 that portion of the bed 12 that may be more densely clogged or otherwise spent and to discharge it from vessel 10. By discharging bed material positioned below perforations 18, space will be provided for the entire bed 12 to move downward and subsequently place unclogged or unspent bed material in the vicinity of perforations 18. Thus, the inlet pressure will be substantially reduced.

The discharge of clogged bed materia is accomplished by stopping the operation of pump 16, closing the inlet valve 38 and the discharge valve 24. Thus, when the pump 16 is de-energized and the valves 24 and 38 are closed, the liquid within the bed 12 will remain substantially stationary. Then the connecting valve 36 is openend and, shortly thereafter, the recycle pump 46 is started. The pump 46 will cause some of the previously treated liquid in tank 28 to be discharged through the lines 44 and 48 into the top of the storage section 40. suflicient operating time is then allowed to enable the pump 46 to build up suflicient hydraulic pressure throughout vessels 40 and 10. When a predetermined pressure has been achieved, the discharge valve 20 at the bottom of vessel 10 is opened. This will allow the previously clogged or spent bed material below the performations 18 to be discharged through the valve 20 accompanied by some amount of fluid. As the spent bed material is released via the open valve 20, fresh material will pass from the vessel 40 into the treatment section 10 and replenish an amount of material that is substantially the equivalent of that which has been discharged by valve 20. Valve 20 is maintained in the open position for a period of time equal to or less than the period of time required for the pressure throughout the vessels 40 and 10 to come to equilibrium with the pressure in the vessel into which coal and clogged solids are being discharged. After valve 20 closes, the valve 34 is opened to further compact the bed and complete the filling of vessel 10 if necessary. The opening of valve 34 enables some of the liquid within the bed 12 to be discharged and this will serve to compact the bed 12 to the point where it will again act as an improved filtering medium. Pump 46 is then de-energized, and valves 34 and 36 are closed. The system is then returned to normal operation by the re-energizing of pump 16 and the opening of valves 38 and 24. The spent bed material, including the sewage solids accompanying it which have been discharged through valve 20, may be disposed of by burning or otherwise.

While the countercurrent system involves an intermittent flow of influent upwardly between the perforated sections 18 and 22 and an intermitten downfiow or discharge of clogged material of bed 18 through the exit valve 20, in certain trial arrangements employing this invention, the upward flow of the effluent continued for periods varying between 30 and 180 minutes, but the surge cycle, for the discharge of spent coal, that is, the interval between the opening and closing of valve 36, lasted no more than about half a minute. Hence there were long filtering periods and relatively short surge cycles. Thus, the equipment performed filtering operations during a high percentage of the available operating time.

For automatic operation, the pressure switch P.S., which is connected to the input line, may control a programmed stepping switch or a programmed series of timers represented by T2 in FIG. 1. These switches and timers will be started in operation upon the influent pressure rising to a predetermined value. On the other hand, the timer actuator T1 may alternatively start the switches and timers after a predetermined interval, such as 30, 60 or minutes. The cycle of operations will involve the following sequential steps:

(1) De-energize the influent pump 16.

(2) Close the inlet and outlet valves 38 and 24.

(3) Open the interconnecting valve 36.

(4) Start recycle pump 46.

(5) Open the bed discharge valve 20.

(6) Close the bed discharge valve 20.

(7) Open the liquid discharge valve 34.

(8) De-energize the recycle pump 46.

(9) Close the liquid discharge valve 34 and connecting valve 36.

(10) Energize the influent pump 16. 11) Open the inlet and outlet valves 38 and 24.

The discharge of liquid via valve 34, as above described, might be omitted if desired, but the system will function considerably better if this step of the operation is retained. If the discharge via valve 34 were omitted, the bed within chamber 10 might not be sufliciently filled with the granular medium and it might tend to fluidize on the resumption of normal operation. The efiiciency of the operation would thereby be reduced. Tests have indicated that the employment of valve 34 for fluid discharge has significant merit.

FIG. 1 depicts the spent material as being discharged through valve 20 into vessel 64 which is substantially at atmospheric pressure. This requires that during the purging operation that the entire beds 12 and 40 be brought up to a pressure somewhat above atmospheric pressure. This is done by closing valves 38 and 24 and operating pump 46 until the desired pressure is reached. Valve 20 is then opened.

It is also possible to accomplish the purging of spent bed material by discharging such material through valve 20 into a vessel maintained at less than atmospheric pressure. This is shown in FIG. 2 which depicts vessel 66 maintained at less than atmospheric pressure by means of vacuum pump 68, communication between the vacuum pump 68 and vessel being provided by pipe 70. A valve 72 is provided so that material wasted from the column 10 and delivered to the vacuum chamber 66 may be removed when required.

Certain examples employing the invention were aS follows:

(1) Raw sewage was passed through a column 6 feet high having an inside diameter of 3% inches and packed with -10 to +100 mesh anthracite coal at a flow rate of 30 gallons per hour per square foot of column cross section. The run lasted 17 days. Periodically during the run, coal and sewage solids were discharged by placing the entire column under pressures which varied from 20 to 40 psi. and opening valve 20 to atmospheric pressure. Suspended solids removal averaged 88.4%, chemical oxygen demand removal averaged 73.9%, coal removal averaged 53.7 pounds per 1,000 gallons of sewage treated.

(2) Raw sewage was passed through a column 6 feet high having an inside diameter of 3% inches and packed with l to +100 mesh antracite coal at a flow rate of 45 gallons per hour per square foot of column cross section. Periodically coal and sewage solids were discharged by placing the entire column under pressure which varied from 20 to 40 psi. and opening valve 20 which was connected to a tank which was maintained at 15 inches of vacuum. Suspended solids removal averaged 90.7% chemical oxygen demand removal averaged 68.5%, coal removal averaged 59.5 pounds per 1,000 gallons of sewage. The run was conducted for four consecutive days.

While the operation of the apparatus has been described with reference to a bed of material, such as coal, for the treatment of sewage, the apparatus is equally and fully suitable for use in any other solids liquid contact process. Some examples of these are: filtration of water for industrial or domestic use through sand or coal, demineralization or softening water with ion exchange resins, de-colorization of sugar solutions with activated carbon, removal of soluble organic matter from water and wastes with activated carbon, and the extraction of soybean oil with solvents.

It will be apparent that the vessels 10 and 40 may be constructed of metallic, plastic or other materials of sufiicient strength to withstand the pressures to be developed in the system.

The fluid inserted from line 48 to the top of vessel 40 has been described as previously treated fluid obtained from tank 28. It will be readily apparent that any other fluid, e.g., water, may be substituted for treated fluid. The salient property is that the inserted fluid transmitted through line 48 be subjected to a predetermined pressure and that such fluid have little or no chemical reaction on the normal contents of vessels 10 and 40 or on the solids or fluids in these vessels.

While this invention has been shown and described in certain particular embodiments merely for the purpose of illustration, it will be understood that the general principles of this invention may be applied to other and widely varied organizations without departing from the spirit of the invention or the scope of the appended claims.

What is claimed is:

1. In a method employing apparatus including a vessel having a vertical column essentially completely filled with granular material, the method of filtering influent material bearing sewage, which consists in inserting the influent material into the vessel at a point near the bottom thereof so that the influent material flows countercurrent against the granular material, removing efiluent liquid product from a point near the top of the vessel, intermittently interrupting the influent material and the efliuent product, inserting a portion of the previously discharged effiuent liquid product into the upper portion of a second vessel positioned above said first vessel, and applying pressure to the first Vessel through said second vessel for discharging some of the material from said first vessel.

2. The method recited in claim 1 in which the liquid product inserted into the upper portion of the said vessel is replaced by water.

3. The combination of a vertical vessel essentially completely filled substantially continually with granular material through which influent material is driven under pressure upwardly through the entire cross-section of said vessel and is discharged as liquid product from the upper region of said vessel, an apparatus for intermittently cleaning clogged granular material from the bottom of said vessel, said apparatus including means for shutting off the incoming influent material as well as the discharging liquid product, and means for applying some of the liquid product to said vessel under sufiicient pressure in order to drive the clogged material out of the bottom of said vessel, and additional means for removing liquid from said vessel to improve the compaction of the granular material within said vessel.

4. The combination recited in claim 3 in which the part of the liquid product to be applied to the vessel to drive clogged material out of the bottom of the vessel is a fluid which has no chemical interaction with the granular material contained within the vessel.

5. The combination recited in claim 3 in which the apparatus also includes means for discharging some of the applied liquid from the bottom of the vessel for facilitating the compaction of the material in said vessel.

6. The combination recited in claim 5 including, in addi tion, means for inserting additional granular material into the top of the vessel to replace the material discharged from the bottom of the vessel and to maintain the vessel substantially filled with said material.

7. The combination of a treatment cylinder and a storage cylinder, both cylinders being filled with granular material and being positioned in vertical alignment with each other so that the storage cylinder is positioned above the treatment cylinder, a normally closed valve coupling said cylinders to each other, a valve-controlled intake line positioned within and near the bottom of the treatment cylinder, an output line near the top of the treatment cylinder for receiving effluent material as it reaches near the top of the treatment cylinder, and apparatus for disposing of clogged granular material accumulated near the intake line within the treatment cylinder, said apparatus including cooperating means for shutting off the valve-controlled intake line and for closing the output line, means for opening the normally closed coupling valve, and means for pumping some of the efiluent material under pressure to the storage cylinder so as to drive the clogged granular material out of the normally closed opening at the bottom of the treatment cylinder and to move some replacement material from the storage cylinder into the treatment cylinder.

8. The combination defined by claim 7 in which said apparatus also includes a drain line at the bottom of the treatment cylinder and means for transmitting fluid through said drain line.

9. The combination of a vertically upstanding treatment vessel filled with granular material which is closed at its bottom, an intake line positioned near the bottom of said vessel for receiving influent material, an output line positioned near the top of said vessel receiving treated material moving upwardly through said vessel and for discharging eifluent product from said vessel, means for disposing of the clogged granular material accumulated near the bottom of said vessel, said means comprising means for shutting off both the intake and output lines and for feeding some of the efliuent product under substantial pressure to said vessel so as to drive clogged material within the vessel out of the bottom of said vessel, and a storage vessel coupled between the treatment vessel and the output line.

10. The combination recited in claim 9 in which the intake line and the output line each have a perforated section within the treatment cylinder including means serving to prevent any of the granular material from entering said lines.

11. The combination defined by claim in which said disposing means includes a drainline near the bottom of the treatment vessel which may be opened to release some of the fluid from the bottom of the vessel to facilitate the compaction of said material in said vessel.

12. The method of treating liquid bearing sewage, which consists of transmitting the influent liquid upwardly through a bed of granular material, removing the treated liquid from a point near the top of the same bed, intermittently re-inserting some of the treated liquid under pressure to the top of the bed through a storage space, and intermittently discharging some of the material from the bottom of the bed, whereby infiuent liquid to be treated is moved only in an upwardly direction through the bed and the bed is moved step-by-step only in a downward direction.

13. The method defined in claim 12, in which some of the liquid within the bed is discharged near the bottom of the bed so as to facilitate the compaction of the bed.

14. The combination of a liquid-treating cylinder filled with granular material, an intake line for feeding to the cylinder liquid to be treated and to be moved only in an upward direction through the cylinder, an output line near the top of the cylinder for receiving the treated liquid, means for periodically pumping some of the treated liquid under pressure into the top of the cylinder, means for periodically discharging some of the material from the bottom of the cylinder, and means for periodically discharging some of the liquid from the bottom of the cylinder, to facilitate the compaction of the material within the cylinder.

15. The combination recited in claim 14 including, in addition, means for periodically supplying replenishing material to the top of the cylinder to replace the discharged material, whereby the cylinder will be maintained substantially filled with material at all times.

16. Apparatus for the treatment of a liquid bearing sewage, comprising a vertical cylinder filled with particles or material, means for causing the liquid to be treated to move unidirectionally upwardly through the cylinder and for the material within the cylinder to be moved periodically downwardly through the cylinder, an input line positioned near the bottom of the cylinder for feeding the liquid to be treated to the bottom of the cylinder, an output line near the top of the cylinder for receiving treated liquid, a pump for periodically pumping some of the treated liquid under pressure to the top of the cylinder, a valve at the bottom of the cylinder through which material within the vessel may be discharged, means for intermittently opening said valve in order to discharge said material from the bottom of the cylinder, and separate means for periodically discharging some of the liquid from the bottom of the cylinder to facilitate the compaction of the material within the cylinder.

17. Apparatus for the treatment of a liquid bearing sewage in accordance with claim 16 including, in addition, vacuum apparatus coupled to said valve at the bottom of the cylinder, said vacuum apparatus increasing the pressure differential between the two sides of said valve at the bottom of said cylinder so as to facilitate the discharge of said material through said valve.

18. Apparatus for the treatment of a liquid bearing sewage in accordance with claim 17 including, in addition, a second valve for discharging liquid from the bottom of the cylinder in order to aid in the compaction of the material within the vessel.

19. A liquid treatment apparatus, comprising a vessel substantially filled with granular material for the treatment of incoming liquids, normally closed upper and lower valves for said vessel through which said granular material may be, respectively, supplied to or removed from said vessel, a closed receptor into which the lower valve discharges, means for supplying liquid under pressure through said upper valve to render the internal pressure within the vessel significantly higher than the internal pressure within said receptor, and means responsive to the difference between the internal pressures of the vessel and the receptor for discharging substantially spent material from said vessel into said receptor.

20. A liquid treatment apparatus according to claim 19, in which the receptor includes means to maintain a pressure which is substantially below atmospheric pressure.

21. A liquid treatment apparatus according to claim 19, in which the receptor includes means for normally maintaining pressure.

22. A liquid treatment apparatus according to claim 19, including means by which liquid is fed into the vessel through the upper valve to raise the pressure within the vessel to the range of twenty to forty p.s.i.

23. A liquid treatment apparatus according to claim 19, including means by which the pressure within said receptor is maintained at a value of about 15 inches of mercury.

References Cited UNITED STATES PATENTS 293,750 2/1884 Hyatt 210-l89 1,620,431 3/1927 Bramwell 2l0l89 2,801,966 8/1957 Meates et a1 210-268 X 3,056,743 10/1962 Eichhorn et al. 210189 X 3,270,886 9/1966 Sackett 210-l89 3,276,585 10/1966 Kalinske 2lO--279 X 3,287. 426 11/1966 Entringer 210-189 X JOHN W. ADEE, Primary Examiner US. Cl. X.R.

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