US3904376A

US3904376A - Apparatus for cleaning the discharge of a smokestack or the like

Info

Publication number: US3904376A
Application number: US444878A
Authority: US
Inventors: Tadao Kawata
Original assignee: Kawada Industries Inc
Current assignee: Kawada Industries Inc
Priority date: 1973-02-23
Filing date: 1974-02-22
Publication date: 1975-09-09
Anticipated expiration: 1992-09-09
Also published as: FR2218927A1; DE2405669A1; JPS49125977U

Abstract

An apparatus to be used with a smokestack to receive the discharge thereof and to clean the discharge in such a way that only non-noxious components are released to the outer atmosphere. The discharge from a smokestack is directed into a mixing chamber where it is mixed with steam from a suitable steam-supply. This mixture is then directed from the mixing chamber through a conduit into a treating tank. Prior to reaching the treating tank the mixture of steam and discharge received from the mixing chamber is cooled and liquefied by a liquefying structure. In the treating tank particulate matter in the liquid is permitted to settle to the bottom of the tank while the liquid can be treated with suitable neutralizing agents to provide in this way a nonnoxious liquid and gas to be released from the treating tank.

Description

United States Patent [191 Kawata 1 Sept. 9, 1975 LIKE [75] Inventor: Tadao Kawata, Japan [73] Assignee: Kawada Kogyo Kabushiki Kaisha,

Japan [22] Filed: Feb. 22, 1974 [21] Appl. No.: 444,878

[30] Foreign Application Priority Data Feb. 23, 1973 Japan 48-22725 [52] U.S. Cl. 23/284; 23/283; 23/262;

SS/DIG. 30; 55/220; 55/223; 55/263;

261/111; 261/17; 261/DIG. 9; 423/242 [51] Int. Cl. B01J l/22; B01D 53/34 [58] Field of Search 23/283, 284, 262; 423/242; 261/111, DIG. 9, 17; 55/DIG. 30, 223, 220,

10/1935 Kennaetal 261/111 12/1972 Chew 55/220 X Primary Examiner-James H. Tayman, Jr. Attorney, Agent, or Firm-Steinberg & Blake [57] ABSTRACT An apparatus to be used with a smokestack to receive the discharge thereof and to clean the discharge in such a way that only non-noxious components are released to the outer atmosphere. The discharge from a smokestack is directed into a mixing chamber where it is mixed with steam from a suitable steam-supply. This mixture is then directed from the mixing chamber through a conduit into a treating tank. Prior to reaching the treating tank the mixture of steam and discharge received from the mixing chamber is cooled and liquefied by a liquefying structure. In the treating tank particulate matter in the liquid is permitted to settle to the bottom of the tank while the liquid can be treated with suitable neutralizing agents to provide in this way a non-noxious liquid and gas to be released from the treating tank.

15 Claims, 4 Drawing Figures APPARATUS FOR CLEANING THE DISCHARGE OF A SMOKESTACK OR THE LIKE BACKGROUND OF THE INVENTION The present invention relates to apparatus for cleaning a smokestack discharge before the latter is released to the outer atmosphere.

As is well known, the products of combustion which form the discharge flowing out of the smokestacks of factories and the like contain noxious components. Primarily the noxious component of the smokestack discharge is As is well known it is this latter compo nent in particular which contaminates the atmosphere in the neighborhood of such smokestacks. Various attempts have been made to clean such exhausts from stacks of factories and the like. Thus electric dust collectors are known, but apparatus of this type removes only the dust and other particulate matter contained in the smokestack discharge. In addition, it is known to provide at the path of the smoke a shower in the form of a suitable spray. However, such attempts at cleaning the exhaust of a smokestack are only partially successful inasmuch a complete cleaning of the smokestack is achieved only upon removal of the chemical noxious contents such as S0 as well as the solids such as dust from the air.

SUMMARY OF THE INVENTION It is accordingly a primary object of the present invention to provide an apparatus which will effectively clean the discharge of a smokestack in such a way that only non-noxious components are released.

In particular it is an object of the present invention to provide an apparatus which takes advantage of the fact that S0 has the property of being water soluble and achieves a removal of S0 from the smokestack discharge by an intimate mixture of the smokestack discharge with water in various forms achieving a highly effective removal of S0 Furthermore, it is an object of the present invention to provide an apparatus of the above type which will improve the manner in which a discharge flows out of a smokestack so that the operation of the combustion apparatus will be enhanced.

In addition, it is an object of the present invention to provide an apparatus of the above type which will make use of energy which otherwise would be wasted, for the purpose of contributing to the cleaning achieved with the apparatus of the invention.

In accordance with the invention the discharge from a smokestack is directed into a mixing chamber means which also communicates with a steam-supply means so that steam is mixed with the smokestack discharge in the mixing chamber means. A conduit means has an inlet communicating with the mixing chamber means to receive the mixture of steam and smokestack discharge therefrom, and this conduit means has distant from its inlet an outlet end communicating with a treating means. Between its inlet and outlet the conduit means is operatively connected with a liquefying means which cools and liquefies the mixture prior to the time that the latter reaches the outlet of the conduit means to flow therefrom into the treating means. In the treating means the products flowing from the outlet of the conduit means are treated in such a way that only a non noxious liquid is released and any air which is also released is also in a non-noxious form. Thus, in accordance with the invention the discharge from the smokestack is initially mixed intimately with steam and the noxious components such as S0 are neutralized and separated by the liquefying action so that what reaches the outer atmosphere is a non-polluting waste liquid and clean air. Since S0 is strongly inclined to be water soluble, the mixture with steam and the subsequent cooling and liquefying removes the chemical noxious contents such as S0 from the smokestack discharge as a result of the mixture with steam and subsequent liquefying treatment. Between a steam chamber which contains a supply of steam and the mixing chamber is located a Venturi means having just above the smokestack a throat for receiving the smokestack discharge as well as the steam from the steam chamber. As a result the steam is fed under pressure into the mixing chamber so as to increase the rate of flow of steam into the chamber beyond what this rate would be without the Venturi means while subjecting the upper discharge end of the smokestack to a negative pressure or minus load, thus sucking the discharge forcibly from the smokestack into the mixing chamber to be mixed with steam therein. The conduit means is of a U-shaped configuration at its inlet end so that it curves first upwardly and then downwardly from the mixing chamber with the conduit means having an elongated downwardly extending portion which is substantially parallel to a com mon axis of the upper discharge end region of the smokestack, the steam chamber, the Venturi means, and the mixing chamber means. Just beyond its U- shaped region the conduit means is operatively connected with the liquefying means so that the mixture is cooled and liquefied just beyond the U-shaped part of the conduit means to flow downwardly along the interior thereof to the treating means. Just before the treating means the conduit means is operatively connected with a blower means which blows air into the conduit means to flow downwardly therein into the treating means with the flow of the liquefied mixture received from the mixing chamber means into the treating means being enhanced by the introduction of the air from the blower means into the conduit means at the part thereof just above the treating means. The conduit means introduces the components into a treating means in the form of a suitable cleaning tank which receives the liquid and gas from the conduit means, and any noxious components are neutralized in the treating tank by a suitable neutralizing agent so that only a nonpolluting waste liquid and a non-noxious gas are released to the outer atmosphere.

BRIEF DESCRIPTION OF DRAWINGS of FIG. 1 in the direction of the arrows and illustrating a Venturi means; and

FIG. 4 is a fragmentary sectional elevation showing in detail a liquefying means which is illustrated at a smaller scale in FIG. 1.

DESCRIPTION OF A PREFERRED EMBODIMENT FIG. 1 schematically illustrates part of a smokestack 1 which has an upper discharge end region. This upper discharge end region of the smokestack 1 extends into the interior of a cylinder 2 which has a lower wall 3 surrounding and fluid-tightly connected with the exterior of the smokestack 1. The cylinder 2 is coaxial with the discharge end region of the smokestack l and has a diameter larger than the discharge end region of the smokestack 1 so as to define therewith a steam chamber 6 which surrounds the upper discharge end region of the smokestack 1. At the region of the lower wall 3, the cylinder 2 is closed except for a small opening which communicates with the interior of a steamsupply pipe which extends upwardly along the exterior of the smokestack 1. The lower end of the pipe 5 receives steam from a boiler 4 which is heated with excess heat which otherwise would be wasted and which results from the combustion which takes place during operation of the factory or other plant, with the products of this combustion forming the discharge which flows upwardly through and beyond the smokestack 1.

Thus, the upper end of the pipe 5 communicates with the steam chamber 6 through an opening at the region of the bottom wall 3 of the cylinder 2 so that in this way the structure provides a steam-supply means allowing steam to flow from the boiler 4 through the pipe 5 into the chamber 6.

The top end of the steam chamber 6 communicates with a Venturi means 7 which has a throat situated just above the discharge end of the smokestack 1, this throat having a diameter smaller than the inner diameter of the cylinder 2 which forms the steam chamber 6. The top end of the Venturi means 7 communicates with a mixing chamber means 9 which thus receives steam from the steam chamber 6 and the discharge from the smokestack 1. The mixing chamber means 9 is in the form of a tubular structure which converges upwardly and in which the steam and smokestack discharge are mixed intimately.

A conduit means has an inlet region 8 of substantially U-shaped configuration communicating with the mixing chamber means 9 to receive therefrom the mixture of steam and smokestack discharge. Thus the inlet end of the conduit means 10 communicates directly with the mixing chamber means 9 which forms an extension of the conduit means 10, and at its U-shaped region 8 the conduit means 10 curves first upwardly and then downwardly. At its downwardly extending elongated portion the conduit means 10 extends vertically in parallel relation with respect to a common axis of the upper discharge end region of the smokestack 1, the cylinder 2, the Venturi means 7 and the mixing chamber means 9.

Just beyond its U-shaped portion 8, the conduit means is operatively connected with a liquefying means in the form of a water jacket 13 which serves to cool and condense the steam flowing downwardly along the interior of the conduit means 10 subsequent to the inlet thereof. The liquefying action is enhanced by way of a spray means 14 which receives water from the interior 15 of the water jacket 13 and sprays the water downwardly and across the interior of the conduit means 10.

Thus, as may be seen particularly from FIG. 4, the interior 15 of the water jacket 13 receives cooling Water from a supply pipe 17. The water jacket is in the form of a cylinder which surrounds the fluid-tightly engages the exterior of the conduit means 10 to define the water jacket space 15 in which the cooling water is located. The spray means 14 is in the form of a circular tube having at its outer region perforations communicating with openings formed in the wall of the conduit means 10 at the lower region of the space 15 so that in this way water flows directly from the space 15 through perforations in the conduit 10 coinciding perforations at the outer region of the circular tube 14 into the interior of the latter. This circular tube 14 which forms the spray means has an inner region formed with openings 16 directed downwardly and across the interior of the conduit means 10. Thus the spray provided from the spray means 14 is directed downwardly and across the interior of the conduit means 10 in an oblique direction as shown by the arrows in FIG. 4.

The conduit means 10 extends downwardly from the

liquefying means

13,14 through a considerable distance before terminating in a bottom outlet end which is situated in the interior of a treating means 23 in the form of a cylindrical settling tank. Thus the lower end region of the conduit means 10 extends fluid-tightly through the top wall of the treating tank 23. The liquid 25 received from the conduit means 10 rises in the tank 23 While accumulating therein. Thus, it will be noted that the lower end region 20 of the conduit means 10 extends directly into the body of liquid 25 which collects in the tank 23. Mounted on the top wall of the tank 23 is a hopper 24 containing a neutralizing agent 26 which can be supplied in a predetermined regulated manner by way of suitable discharge valve or the like to the interior of the tank 23 to be received by the liquid 25 for neutralizing in a known way any noxious components of the liquid 25. The liquid 25 is thus stored for a given time in the tank 23 and particulate matter 29 will settle to the bottom of the tank as illustrated. Clean air which is situated above the body of liquid 25 is permitted to escape to the outer atmosphere through the gas outlet 28 of the tank 23 while clean liquid will flow out through the overflow opening 27.

The steam from the boiler 4 is delivered by way of the pipe 5 to the interior of the steam chamber 6 under pressure prior to being combined with the smokestack discharge which contains S0 The flow of the steam through the throat of the Venturi means 7 together with the discharge from the stack 1 creates a minus load or negative pressure which is to say a pressure less than atmospheric pressure directly above the top end of the smokestack 1, and thus the discharge is sucked out of the smokestack 1 into the mixing chamber 9 together with the steam introduced under pressure into the chamber 6 from the pipe 5. Thus, the discharge from the smokestack is forcibly drawn up into the mix ing chamber means 9 at the negative pressure which acts on the top end of the smokestack, with intimate mixing between the steam and discharge taking place in the mixing chamber means 9. This mixture of steam and smokestack discharge is directed through the U- shaped portion 8 of the conduit means 10 downwardly along the interior of the latter. This downward flow of the mixture along the conduit means 10 is enhanced by a blower means 21 which feeds air into the conduit means 10 at a lower region thereof just above the treating means 23.

With the downward flow enhanced as a result of the action of the blower means 21, the mixture is smoothly drawn into the vertical part of the conduit means It from the U-shaped portion 8 thereof, and inasmuch as cooling takes place next to the U-shaped portion 8 by way of the water jacket 13, the result is a rapid cooling and liquefying of the mixture with the particulate matter of the smokestack discharge therein, the liquefying action being accelerated by the spray means 14 which operates to spray water constantly toward the interior of the conduit 10.

With the contents now completely liquefied, flow thereof takes place along the inner surface of the conduit means toward the treating means formed by the cleaning tank 23. The blower means 21 includes a pipe 19 communicating through an opening 18 with the interior of the conduit means 10. This opening 18 is covered by a baffle 22 which directs the air from the pipe 19 downwardly along the interior of the conduit means 10 while preventing liquid from flowing across the opening 18. Thus, as a result of the baffle 22 which covers the opening 18 there is no danger that this opening 18 will become clogged with liquid while at the same time the operation of the structure for a long period is enhanced.

Thus, the liquid 25 is received in the cleaning or treating tank 23 to be stored therein until a certain amount accumulates while the neutralizing agent required for cleaning purposes is received in the tank 23 from the hopper 24. In this way the particulate matter 29 will settle to the bottom of the tank 23 and a clean,

neutralized, non-polluting water will flow out through the outlet 27. Although not illustrated the bottom wall of the tank 23 may be provided with a removable plug which can be removed from time to time so that the deposits 29 can be removed.

Thus, with the invention described above separation of the noxious components from the smokestack discharge is facilitated particularly as a result of the mixing of the smokestack discharge with steam at the region just beyond the upper end of the smokestack. while the particulate noxious matter and smoke particles form nuclei of droplets of water while the mixture is cooled and liquefied. As a result it becomes possible to eliminate substantially all of the S0 which is the primary pollutant to be removed from the discharge before releasing the latter to the outer atmosphere. In this way it is possible with the present invention to provide an effective anti-pollution apparatus of considerable advantage to industry.

The neutralizing agent 26 may be, for example, Na CO CaOH or NaHCO What is claimed is:

1. In an apparatus to be used with a smokestack having a discharge end region from which a discharge flows outwardly beyond the smokestack, mixing chamber means fluid-tightly communicating with the discharge end region of the smokestack for receiving the discharge therefrom, steam-supply means communicating with said mixing chamber means for supplying thereto steam to be mixed with the discharge from the smokestack, conduit means having an inlet end communicating with said mixing chamber means to receive the mixture of steam and smokestack discharge therefrom and an outlet end distant from said mixing chamber means, said conduit means directing the mixture from said mixing chamber means to said outlet end of said conduit means, liquefying means operatively connected with said conduit means between said ends thereof for cooling the mixture flowing through said conduit means and for liquefying at least a substantial portion of the mixture before the mixture reaches said outlet end of said conduit means, and treating means communicating fluid-tightly with the outlet end of said conduit means for treating the products received from said outlet end of said conduit means in a manner providing for release of only non-noxious components from said treating means, said mixing chamber means being of a tubular configuration and forming an extension of said inlet end of said conduit means extending from the latter toward said discharge end region of said smokestack, said steam-supply means including a cylindrical enclosure fluid-tightly surrounding and spaced in part from said discharge end region of said smokestack for defining with the exterior of the smokestack at said discharge end region thereof a steam chamber from which steam flows with the discharge of the smokestack into said mixing chamber means, a Venturi means being situated between said steam chamber and mixing chamber means and having a throat region situated adjacent but beyond said smokestack for receiving at its throat region both the discharge from the smokestack and the steam from the steam chamber and fordirecting the steam from the steam chamber and the discharge from the smokestack at less than atmospheric pressure into the mixing chamber means, said discharge end region of said smokestack, said steam chamber, Venturi means, and mixing chamber means all having a common upright axis with said steam chamber and discharge end region of said smokestack being situated at the same elevation while said Venturi means is situated at a higher elevation than said steam chamber and said mixing chamber means is situated at a higher elevation than said Venturi means, said conduit means being of a substantially U-shaped configuration at the region of its inlet and curving from said inlet first upwardly and then downwardly and extending downwardly from said U-shaped region in a direction substantially parallel to said common axis, said liquefying means being operatively connected with said conduit means at a part thereof which is situated beyond but adjacent said U-shaped region.

2. The combination of claim 1 and wherein a blower means communicates with said conduit means between said liquefying means and treating means for blowing air into said conduit means to flow with the contents thereof into said treating means.

3. The combination of claim 2 and wherein a baffle means is carried by said conduit means in the interior thereof at the location where air enters said conduit means from said blower means to deflect the air downwardly along the interior of said conduit means while preventing contact between liquid in said conduit means and air at the location where said blower means communicates with said conduit means.

4. The combination of claim 3 and wherein said liquefying means includes a water jacket surrounding said conduit means.

5. The combination of claim 4 and wherein said liquefying means includes a spray means situated in said conduit means and communicating with said water jacket for receiving water therefrom for spraying the water across the interior of said conduit means.

6. The combination of claim 5 and wherein said spray means is in the form of a circular tube having an outer region communicating through said conduit means with the interior of the water jacket and an inner region formed with apertures for directing a liquid spray downwardly and across the interior of said conduit means.

7. The combination of claim 6 and wherein said treating means includes a settling tank for receiving liquid from said conduit means while permitting particulate matter to settle to the bottom of said tank.

8. The combination of claim 7 and wherein said settling tank has an overflow outlet situated at a substantial distance above the bottom of the tank through which liquid overflows and a gas outlet above said overflow outlet and through whch gas escapes.

9. The combination of claim 8 and wherein said tank carries at an upper region thereof a means for supply ing to the tank a neutralizing agent for reacting with liquid in the tank to neutralize any noxious components therein for rendering them non-noxious and for enhancing the settlement of particulate matter to the bottom of the tank.

10. The combination of claim 1 and wherein said liquefying means includes a water jacket surrounding said conduit means.

11. The combination of claim 10 and wherein said liquefying means includes a tubular ring situated in said conduit means and having an outer region communicating with said water jacket for receiving water therefrom and an inner region formed with spray apertures from which liquid is sprayed across the interior of said conduit means.

12. The combination of claim 1 and wherein said treating means includes a settlement tank for receiving liquid from said outlet of said conduit means while permitting particulate matter in the liquid to settle to the bottom of the tank.

13. The combination of claim 12 and wherein said settlement tank has at an elevation substantially higher than its bottom an overflow outlet through which liquid overflows from the tank and at an elevation higher than said overflow outlet a gas outlet through which gas flows from the tank.

14. The combination of claim 13 and wherein said settling tank carries a supply means for supplying to the interior of the tank a neutralizing agent to be received by the liquid in the tank for neutralizing any noxious components and rendering the latter non-noxious before liquid flows out through said overflow outlet and gas flows out through said gas outlet.

15. The combination of claim 1 and wherein a boiler means communicates with said steam chamber for supplying steam thereto.

Claims

1. IN AN APPARATUS TO BE USED WITH A SMOKESTACK HAVING A DISCHARGE END REGION FROM WHICH A DISCHARGE FLOWS OUTWARDLY BEYOND THE SMOKESTACK, MIXING CHAMBER MEANS FLUID-TIGHTLY COMMUNICATING WITH THE DISCHARGE END REGION OF THE SMOKESTACK FOR RECEIVING THE DISCHARGE THEREFROM, STEAM-SUPPLY MEANS COMMUNICATING WITN SAID MIXING CHAMBER MEANS FOR SUPPLYING THERETO STEAM TO BE MIXED WITH THE DISCHARGE FROM THE SMOKESTACK, CONDUIT MEANS HAVING AN INLET END COMMUNICATING WITH SAID MIXING CHAMBER MEANS TO RECEIVE THE MIXTURE OF STEAM AND SMOKESTACK DISCHARGE THEREFROM AND AN OUTLET END DISTANT FROM SAID MIXING CHAMBER MEANS, SAID CONDUIT MEANS DIRECTING THE MIXTURE FROM SAID MIXING CHAMBER MEANS TO SAID OUTLET END OF SAID CONDUIT MEANS, LIQUEFYING MEANS OPERATIVELY CONNECTED WITH SAID CONDUIT MEANS BETWEEN SAID ENDS THEREOF FOR COOLING THE MIXTURE FLOWING THROUGH SAID CONDUIT MEANS AND FOR LIQUEFYING AT LEAST A SUBSTANTIAL PORTION OF THE MIXTURE BEFORE THE MIXTURE REACHES SAID OUTLET END OF SAID CONDUIT MEANS, AND TREATING MEANS COMMUNICATING FLUIDTIGHTLY WITH THE OUTLET END OF SAID CONDUIT MEANS FOR TREATING THE PRODUCTS RECEIVED FROM SAID OUTLET END OF SAID CONDUIT MEANS IN A MANNER PROVIDING FOR RELEASE OF ONLY NON-NOXIOUS COMPONENTS FROM SAID TREATING MEANS, SAID MIXING CHAMBER MEANS BEING OF A TUBULAR CONFIGURATION AND FORMING AN EXTENSION OF SAID INLET END OF SAID CONDUIT MEANS EXTENDING FROM THE LATTER TOWARD SAID DISCHARGE END REGION OF SAID SMOKESTACK, SAID STEAM-SUPPLY MEANS INCLUDING A CYLINDRICAL ENCLOSURE FLUID- TIGHTLY SURROUNDING AND SPACED IN PART FROM SAID DISCHARGE END REGION OF SAID SMOKESTACK FOR DEFINING WITH THE EXTERIOR OF THE SMOKESTACK AT SAID DISCHARGE END REGION THEREOF A STEAM CHAMBER FROM WHICH STEAM FLOWS WITH THE DISCARGE OF THE SMOKESTACK INTO SAID MIXING CHAMBER MEANS, A VENTURI MEANS BEING SITUATED BETWEEN SAID STEAM CHAMBER AND MIXING CHAMBER MEANS AND HAVING A THROAT REGION SITUATED ADJACENT BUT BEYOND SAID SMOKESTACK FOR RECEIVING AT ITS THROAT REGION BOTH THE DISCHARGE FROM THE SMOKESTACK AND THE STEAM FROM THE STEAM CHAMBER AND FOR DIRECTING THE STEAM FROM THE STEAM CHAMBER AND THE DISCHARGE FROM THE SMOKESTACK AT LESS THAN ATMOSPHERIC PRESSURE INTO THE MIXING CHAMBER MEANS, SAID DISCHARGE END REGION OF SAID SMOKESTACK, SAID STEAM CHAMBER, VENTURI MEANS, AND MIXING CHAMBER MEANS ALL HAVING A COMMON UPRIGHT AXIS WITH SAID STEAM CHAMBER AND DISCHARGE END REGION OF SAID SMOKESTACK BEING SITUATED AT THE SAME ELEVATION WHILE SAID VENTURI MEANS IS SITUATED AT A HIGHER ELEVATION THAN SAID STEAM CHAMBER AND SAID MIXING CHAMBER MEANS IS SITUATED AT A HIGHER ELEVATION THAN SAID VENTURI MEANS, SAID CONDUIT MEANS BEING OF A SUBSTANTIALLY U-SHAPED CONFIGURATION AT THE REGION OF ITS INLET AND CURVING FROM SAID INLET FIRST UPWARDLY AND THEN DOWNWARDLY AND EXTENDING DOWNWARDLY FROM SAID U-SHAPED REGION IN A DIRECTION SUBSTANTIALLY PARALLEL TO SAID COMMON AXIS, SAID LIQUEFYING MEANS BEING OPERATIVELY CONNECTED WITH SAID CONDUIT MEANS AT A PART THEREOF WHICH IS SITUATED BEYOND BUT ADJACENT SAID U-SHAPED REGION.

9. The combination of claim 8 and wherein said tank carries at an upper region thereof a means for supplying to the tank a neutralizing agent for reacting with liquid in the tank to neutralize any noxious components therein for rendering them non-noxious and for enhancing the settlement of particulate matter to the bottom of the tank.