US3645218A

US3645218A - Solid waste incinerator

Info

Publication number: US3645218A
Application number: US36636A
Authority: US
Inventors: Leonard A Davis
Original assignee: GARVER DAVIS Inc
Current assignee: GARVER DAVIS Inc
Priority date: 1970-05-12
Filing date: 1970-05-12
Publication date: 1972-02-29
Anticipated expiration: 1989-02-28
Also published as: CA932212A

Abstract

A method of and apparatus for incinerating a wide range of solid waste materials in a smokeless, odorless manner, Solid wastes are contained within a combustion chamber in a whirling, driving, vortical, rotating envelope of air that is present in an excess of that theoretically required to burn the waste. A combustible fuel is burned within the chamber. The particulates resulting from the combustion of the waste materials are suspended within the resulting burning cyclone of air and fuel, burned, and the effluent vented from the combustion chamber. Preferably, an afterburner is used to burn any lighter weight particulate matter that may escape from the combustion chamber.

Description

United States Patent Davis Feb. 29, 1972 [54] SULID WASTE INCINERATOR 3,482,533 12/1969 Ankersen ..l10/8 [72] Inventor: Leonard A. Davis, Mentor, Ohio Primary Examiner Kenneth w p g [73] Assignee: Garver-Davis Incorporated, Cleveland, Att0rneyBosworth, Sessions, Herrstrom & Cain Ohio 221 Filed: May 12, 1970 [57] ABSTRACT [2]] App]. Nu: 36,636 A method of and app aratus for incinerating a wide range of SOlld waste materials In a smokeless, odorless manner, Solid wastes are contained within a combustion chamber in a US. Cl- ]R, l A, C whirling driving vertical rotating envelope of air that is [51] Int. Cl. ..F23g 512 present in an excess f that theoretically required to hum the [58] Fleld of Search "1 10/7, 8, 8 A, 8 C, 18, 18 C waste. A combustible fuel is burned i i the chamber The particulates resulting from the combustion of the waste [56] References and materials are suspended within the resulting burning cyclone UNITED STATES PATENTS of air and fuel, burned, and the effluent vented from the combustron chamber. Preferably, an afterburner is used to burn 3,456,604 7/1969 Ehrenldler et 10/3 any lighter weight particulate matter that may escape from the Toepel combustion chamber 3,215,501 11/1965 Phillips ..1 10/8 X 3,408,167 10/1968 Burden, Jr. ..1 10/8 X 19 Claims, 4 Drawing Figures PAIENTEDFEB 29 I972 SHEET 1 OF 3 INVENTOR Lso/vma A. DAV/.5 5

IO N

ATTORNEYS PMENTEDFEB 29 I972 SHEET 2 UF 3 INVENTOR LEONA/70 A. DAV/.5

ATTORNEYS PAIENTEDFB29 I972 SHEET 3 OF 3 illlll mm mm I T NV INVENTOR LEONARD A. 04 W5 ATTORNEYS SOLID WASTE INCINERATOR BACKGROUND OF THE INVENTION In recent years, population centers have become acutely aware of air pollution. Incinerators commonly used for disposing of rubbish and waster matter, both commercially and residentially, have contributed to this growing pollution problem through emission of offensive smoke, odor, and the like.

This has resulted, in part, from the structures of prior incinerators which have not been able at all times to provide complete combustion of the solid waste. For example, some prior solid waste incinerators burn the waste material over grates. Combustion-supporting air passes upwardly through the grates, so that the main force of the air is directed against only one side of the waste material and, moreover, in the same direction that the hot gases resulting from combustion tend to move.

Another type of burner which does not employ grates is the open-pit burner in which a horizontal row of air nozzles extends longitudinally along one side of a pit. The nozzles are directed across the open top of the pit and inclined downwardly about 30 to provide a cylindrical curtain of air swirling about the solid material. However, the axis of such circulation is horizontal so that buildup of unconsumed material lying in the bottom of the pit tends to interrupt and interfere with any cyclonic circulation that might otherwise be established.

A principal object, therefore, of the present invention is to provide a method and apparatus for complete incineration of solid waste materials in as short a time as possible and without smoke, odor, or other pollutants being directed into the atmosphere.

SUMMARY OF THE INVENTION In accordance with the present invention, a combustible fuel, usually gas, is admitted along with an excess of air into a combustion chamber. The air is introduced in a manner to form a swirling, cyclonic envelope within which the combustion of solid waste materials are entrapped and supported. Preferably, the air is introduced as a multiplicity of individual streams in substantial parallelism with each other. The air is present in an amount at least 50 percent in excess of the theoretical minimum needed to burn the waste materials. The combustion chamber has an enclosed circular wall along which at least the streams of air are peripherally directed to promote the desired cyclonic motion.

The resulting swirling, vortical envelope receives the mass of solid waste materials and both supports and confines the combustion of the waste within the cyclonic envelope while the wastes are consumed by the fuel and air which serves as primary air for their combustion.

At the same time, the relatively large volumes of air tangentially entering the combustion chamber not only keep the combustion away from the walls or sides of the chamber, but also tend to cool the sides by constant flow thereover. The effluent follows a helical path from the twirling cyclone and exits through a vent in the combustion chamber.

In the preferred fon'n, the efiluent leaves the combustion chamber through an offcenter opening with respect to the axis of the cyclonic motion. The effluent may also pass through a second combustion chamber or afterbumer to burn any combustible matter that may escape from the first combustion chamber, while its velocity is slowed in order to deposit particulate matter which it contains.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a plan view of one embodiment of the present incinerator;

FIG. 2 is an offset section of FIG. 1 on the line 22;

FIG. 3 is a fragmentary view of the air jet nozzle system of the embodiment of FIG. 1, taken on the plane of the line 33; and

FIG. 4 is an enlarged, fragmentary section of FIG. 3 taken on the line 4-4;

DESCRIPTION OF THE PREFERRED EMBODIMENT Apparatus The embodiment illustrated includes a first or primary combustion chamber generally indicated at 10 comprising a platform 11 of beams supporting a cylindrical metal shell 12 of heavy gauge carbon steel having a refractory lining 13. The combustion chamber preferably has means to charge waste materials as well as means to reach the interior of the chamber for cleaning purposes. These features do not form part of the present invention and may take any convenient form. For example, in FIG. 2 of the embodiment illustrated, the shell 12 has an opening 14 extending through the refractory lining 13 and aligned with a refractory lined extension 15 of rectangular cross section. A charge rack 16 supports a feed hopper l7 and a horizontally reciprocating ram 18 which may be conventionally powered as by a hydraulic cylinder. A fire door 21 pivotally hinged along its upper edge 22 normally closes the opening 14. A diametrically opposite opening 23 provides access for cleaning. A door 24 normally closes the opening 23. Reinforced angle irons 25 secured to the upper and lower edges of the door 24 pivotally support it as at 26 (FIG. 1) for opening and closing.

A cooperating gas and air supply system located outside of the combustion chamber 10 discharges those gases into the chamber to form the described cyclonic motion. In FIG. I, such a system is shown generally at 27 and another like system is represented at 28 diametrically opposite the chamber 10 from the first system. Since both systems may be identical, only one is described in detail. In fact, only one air and gas system may be needed, two systems being employed as illustrated for installations of larger diameter and/or when relatively large charges of waste materials are to be incinerated.

Referring more particularly to the system indicated at 27, an electric motor 30 drives a blower 31 having a screened intake 32 and an upwardly extending discharge conduit 33 coupled to pipe 34 (FIG. 3). Pipe 34 makes a T-connection with pipe 35, blocked at its free end and connected through a diverging conduit 36 to a vertically disposed manifold or header 37. Each of a series of pipes 38 aligned longitudinally of the manifold 37 extend serially through a butterfly valve 40 and coupling 41 to a pipe 42. The pipes 42 pass through the outer shell 12 and refractory lining 13 and terminate in nozzle jets 43. The jets are turned toward the curving wall of the combustion chamber, as shown in FIG. 1, to discharge air peripherally of the wall of the circular chamber 10.

A gas-fired burner is mounted on and extends into the combustion chamber below the air nozzles 43. As shown especially by FIGS. 1 and 3, a gas supply pipe 44 extend to a conventional nozzle-mix burner 45 suitably held with respect to the outer shell 12 by an integral flange 46 and carried within aligned matching openings in the shell and refractory lining 13. An air bleed line 47 extends from pipe 35 to burner 45 to provide primary air for combustion of the gas within the chamber 10. A burner jet nozzle 48 extends from the mixing burner into the chamber 10. Combustion chamber 10 has a vent opening 50 to release efiluent.

It is within the contemplation of the present invention to provide an incinerator comprising a single combustion chamber as just described. However, in the preferred form, a second combustion chamber, generally indicated at 51 in the figures, receives the effluent from the opening 50 which is preferably offcenter with respect to the longitudinal axis of the combustion chamber 10 or of the swirling cyclonic motion in order to bring the effluent passing through the opening 50 closer to a burner of the second combustion chamber and promote better afterbuming. The primary purpose of the secondary combustion chamber 51 is to remove particulate matter and/or more completely burn smoke and other pollu tants that may escape the primary combustion chamber 10. In

the form illustrated, the secondary combustion chamber 51 includes a shell 52 having a refractory lining 53 provided with a floor opening 54 which is aligned with the outlet opening 50 of the primary combustion chamber by means of a flue 55. An upper vent opening 56 is offcenter of secondary combustion chamber 51. Steel beams 57 interfitted between the floor of chamber 51 and the upper wall of chamber support the two chambers with respect to each other.

A conventionally fed, gas burner 58, which for example may be operated on aspirated air, extends through a wall of the secondary combustion chamber 51 and is directed substantially across the entrance opening 54. A tunnellike baffle plate 60 extends from the burner 58 past the opening 54 to define an open-ended enclosure of generally semicircular cross section resting on the floor of the secondary combustion chamber 51 and covering the burner 58 and entrance port 54. The volume of the secondary combustion chamber 51 is relatively large as compared to that of the flue 55, such that the velocity of the effluent is substantially reduced upon reaching the chamber 51. This facilitates the deposition of particulate matter from the effluent in the chamber 51. The secondary combustion chamber 51 permits the incinerator to meet certain high standards for air pollution control. The dual combustion chamber unit, for example, burns smoke and meets a widely accepted and often proposed standard requiring that flue gases admitted to the atmosphere contain no more than 0.2 pounds of particulate matter per 1,000 pounds of flue gas. Method In operation, burner 45 is initially lighted and preferably continues to burn throughout the incineration. The burner may be automatically throttled by standard means to accommodate variations in the heat value of the waste material being incinerated. The discharges from the air jets 43 flow in substantially parallelism and, aided by the laterally bent position of the nozzles 43, as shown especially by FIG. 1, the airflow moves peripherally of the circular wall of the primary combustion chamber 10 to form the swirling, vortical, cyclonic movement described. Air is provided in an amount at least 50 percent more than that theoretically required for complete combustion of the solid waste. The air may be supplied from the blower 31 at l6-ounce gauge pressure to provide up to 6,400 cubic feet per hour, for example, for each square foot of effective hearth area. When the primary combustion chamber is at operating temperature, such as about 1,600 E, solid waste is next introduced, as through door 21. The relatively heavy waste materials fall to the floor of the combustion chamber 10 and ignite, the floor of the chamber comprising a refractory material (FIG. 2) and serving as a hearth. As the waste material burns, particulate, incompletely combusted waste matter rises and becomes caught in the rotating envelope of burning gas and air to continue its combustion.

The rotary movement of the gas and air maintains the combustion of solid waste away from the wall of the combustion chamber 10 and toward its center. At the same time, this action provides a self-cooling effect on the inner walls of the combustion chamber as the air sweeps around the curving wall. Simultaneously, the air becomes progressively heated as it moves toward the vortex of the cyclone and mixes with the combustible gases from the burning solid waste. Further, the same air motion provides an effective seal at the area of the door 21 by moving thereacross. When door 21 is opened, the pressure in the opening is approximately zero, facilitating the introduction of solid waste. Very little heat escapes through the door 21 because of the effective air seal.

The mass of particulate and solid waste being consumed is confined in the vortex of the cyclone in the center of the combustion chamber 10. Sufficient quantities of air are available and directed into, at, and around the mass of burning material at air delivery rates promoting complete and rapid combustion. The combustion of solid waste is generally suspended or supported in the vortex with the flame tip dancing in approximately the upper third of the chamber 10. The burning particulates spin under the influence of the cyclone, and heavy particulate is to a large extent thrown to the outside of the vortex and against the interior walls of the cylindrical combustion chamber 10 by centrifugal force. From the walls, the particulate matter drops to the floor of the chamber and/or is confined in the current of air next to the chamber wall and re peatedly thrown against it.

The effluent follows the helical path of the cyclonic motion through the flue 55 and into the second combustion chamber 51 which may be operated at temperatures of l,400 to 1,500 F., for instance. As indicated, the primary purpose of the secondary combustion chamber is to remove more completely particulate matter and/or to burn smoke and other pollutants that may escape from the primary combustion chamber 10. The particulate matter is removed from the effluent by sharply reducing its velocity by means of abrupt changes in volumes of the space through which the effluent flows. For example, the velocity of the efiluent in flue 55 may be of the order of five times its velocity in the much larger space of secondary combustion chamber 51. This reduction in velocity permits the particulate matter to drop from the effluent and onto the floor of the secondary combustion chamber 51. The path of the effluent in combustion chamber 51 is shown generally by the arrows 61. Burner 58 operates directly into the outflow of the flue and is directed axially of the continuing tunnellike baffle 60 to promote and accomplish the more complete removal by burning and/or after burning of smoke, odors, and other pollutants from the effluent.

If desired, automatic controls may be used to adjust the amount of gas supplied to burner 45 in the primary combustion chamber. The burner, for example, may be operated with a gas input necessary to maintain a predetermined minimum temperature in the primary chamber. This may be accomplished by sensing the temperature, as by a thermocouple probe, located above the level of the burner 45 and at an arbitrarily selected point in the heat zone. If the sensed temperature falls below the predetermined temperature, the gas input to the burner is increased by conventional means and vice versa. The requirement for gas varies with the B.t.u. content and/or moisture present in the solid waste to be incinerated. A second similar temperature sensor may also be used to control the amount of heat supplied by burner 45 in the primary chamber. The controls may be arranged so that more gas is supplied when the temperature sensed by the second sensor falls below a predetermined level, even though the first sensor is not at a temperature calling for more heat. The decrease of heat, however, is normally only under the control of the sensor in the primary combustion chamber.

Burner 45 in the primary combustion chamber 10 should be rated to accommodate the general nature of the waste to be incinerated. This burner might, for example, be rated from 1 to 5 million B.t.u.s. Burner 58 in the secondary combustion chamber 51 normally operates at a constant level of temperature and may be throttled automatically and have inputs ranging from approximately 300,000 to 4 million B.t.u.s.

A leading advantage of the present incinerator is its ability to burn measured quantities of solid waste material more nearly completely and in a shorter time without smoke, odor, and the like than other types of incinerators. This advantage is believed to stem from the supply of excess air and the cyclonic arrangement of the gas and air supply. The circulating air surrounding the buming mass of waste material makes available increased and large quantities of air and physically promotes combustion of all organic wastes confined in the vortex of the cyclone. The excess air is automatically used as demanded by the amount of waste as charged.

A wide range of waste products can be incinerated in the present apparatus with stack gas emissions that meet existing codes. Some of the waste products which have been incinerated in embodiments of the present apparatus are polyester fibers, polypropylene cloth, polyethylene, wood pulp products and residue, rubber hose, shredded rubber tires, phenolics, nylon, rayon, latex and polyurethane foams, paint resins, scrap wood, paper, cardboard, rags, sawdust, wood chips, and the like.

Those skilled in the art will appreciate that various changes and modifications can be made in the apparatus and method described herein without departing from the spirit and scope of the invention.

What is claimed is:

1. Apparatus for disposing of solid waste comprising a combustion chamber having a closed circular wall and adapted to receive the solid waste to be disposed, a burner carried by said wall and positioned to direct its discharge into the combustion chamber, and a series of airports stationed axially of said wall and adapted to direct air inside the combustion chamber and peripherally around the closed circular wall to form a driving, vortical, rotating envelope for entrapping and supporting the waste to be burned, the discharge of said airports chemically supporting combustion of burnable waste within said envelope, said combustion chamber having a vent to release effluent.

2. Apparatus according to claim 1 in which said air ports have jet nozzles.

3. Apparatus according to claim 1 in which said vent is an opening having an axis eccentric with respect to the longitudinal axis of the combustion chamber.

4. Apparatus according to claim 1 in which said combustion chamber has a charging door for entry of said solid waste, and said air ports are stationed adjacent said door to provide a seal thereover by means of the air discharge directed peripherally along the closed circular wall.

5. Apparatus according to claim 1 in which said burner is stationed in the circular wall remote from said vent, and said airports are intermediate said burner and vent.

6. Apparatus according to claim 1 in which said vent connects to a second combustion chamber having a burner adapted to burn any combustible matter escaping the first combustion chamber.

7. Apparatus according to claim 6 in which said vent enters said second combustion chamber through an entrance port, the burner of the second combustion chamber is directed substantially across said entrance port, and a baffle plate extends over the burner and past said port to aid in reducing the velocity of the effluent and subsequent removal therefrom of particulate matter.

8. Apparatus according to claim 7 in which said baffle plate is essentially tunnellike and defines an open-ended enclosure covering said burner and entrance port.

9. Apparatus according to claim 1 in which the vent is an opening stationed offcenter with respect to the longitudinal axis of said first-mentioned combustion chamber, and said vent connects to a second combustion chamber having a burner adapted to burn any combustible matter escaping the first combustion chamber, the relative volumes of the second combustion chamber and vent being such as to reduce substantially the velocity of such effluent in passing from the first combustion chamber to the second combustion chamber to aid in removing therefrom particulate matter.

10. Apparatus according to claim 1 in which a second series of airports is mounted in said closed circular wall of the combustion chamber diametrically opposite the first-mentioned series of airports, the two series of airports being adapted to direct their discharge in the same direction peripherally around the circular wall.

11. Apparatus according to claim 1 in which said closed circular wall of the combustion chamber is substantially vertically disposed.

12. A method of incinerating solid waste within a combustion chamber, comprising admitting a combustible fuel into said combustion chamber, discharging a plurality of airstreams into said combustion chamber in substantial parallelism to form a driving, vortical, rotating envelope, introducing solid waste into said envelope, suspending and confining the particulates within the envelope and away from sides of the combustion chamber by means of the rotation of the envelope, burning said waste in said envelope while chemically supporting its combustion by said air, and venting the resulting effluent from the combustion chamber.

13. A method according to claim 12 in which the air supplied is at least 50 percent more than that theoretically required for complete combustion of said waste.

14. A method according to claim 12 in which said fuel is gas.

15. A method according to claim 12 including venting said effluent from the combustion chamber eccentrically with respect to its longitudinal axis.

16. A method according to claim 12 in which said combustible fuel is discharged into the combustion chamber at a point remote from that at which the effluent is vented, and said plurality of airstreams is discharged into the combustion chamber at points intermediate the discharge of the fuel and point of venting.

17. A method according to claim 12 including passing said effluent into a second combustion chamber and burning therein any combustible matter escaping the first-mentioned combustion chamber.

18. A method according to claim 17 including baffling the flow of the effluent from the first to the second combustion chamber to aid in reducing the velocity of the effluent and subsequent removal therefrom of particulate matter.

19. A method according to claim 17 in which passing said effluent into a second combustion chamber includes passing the effluent into a chamber of sufiiciently enlarged volume as to reduce its velocity and aid in removing therefrom particulate matter.

Claims

2. Apparatus according to claim 1 in which said air ports have jet nozzles.

14. A method according to claim 12 in which said fuel is gas.

19. A method according to claim 17 in which passing said effluent into a second combustion chamber includes passing the effluent into a chamber of sufficiently enlarged volume as to reduce its velocity and aid in removing therefrom particulate matter.