US3695192A

US3695192A - Combustion product processing device and method

Info

Publication number: US3695192A
Application number: US79892A
Authority: US
Inventors: Joe W Von Brimer
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-10-12
Filing date: 1970-10-12
Publication date: 1972-10-03
Anticipated expiration: 1989-10-03

Abstract

A combustion product processing device for use with a furnace or other burner which includes means for imparting a helical flow pattern to an influent gas stream entering a smokestack generally axially thereof wherein the stack has inlets for additional combustion air and means such as a gas jet or the like to promote ignition of at least those portions of the combustion products passing nearest the sidewalls. The tangentially injected, higher velocity gases impart a swirling action to the slower, axially flowing combustion products, causing an overall helical combustion product flow pattern, resulting in virtually complete combustion of the products. By reason of longer dwell or residence time within the tack, higher pressures caused by centrifugal force, and higher temperatures causing combustion rate increases, greatly decreased emissions result. In one embodiment the top or outlet end of the stack is fitted with a heavy particle separator adapted to collect particulate residues, or denser gases for subsequent treatment or collection, and in most other embodiments, means are filled at the outlet end of the stack to minimize axial flow and promote helical flow therefrom.

Description

States Patent Von Brimer [451 Oct. 3, 1972 [s41 coivmUsTmN PRODUCT PROCESSING DEVICE AND METHOD [72] Inventor: Joe W. Von Brimer, 3664 Vegas Plaza Dr. Apt. 2, Las Vegas, Nev. 89102 22 Filed: Oct. 12, 1970 21 App1.No.: 79,892

[52] US. Cl. ..1l0/8 A, 110/160 [51] Int. Cl. ..F23g 5/12 [58] Field of Search ..110/8 R, 160

[56] References Cited UNITED STATES PATENTS 3,215,501 11/1965 Phillips ..l l0/8 X 3,364,286 1/1968 Hanks ..1 10/160 X 3,566,811 3/1971 Tidd etal ..1l0/l60X 3,567,399 3/1971 Altman et a1. ..l10/8 X 3,584,851 6/1971 Inman et al ..110/160 FOREIGN PATENTS OR APPLICATIONS 898,237 6/1962 Great Britain ..110/8 Primary Examinerl(enneth W. Sprague Att0rneyGreist, Lockwood, Greenawalt & Dewey ABSTRACT A combustion product processing device for use with a furnace or other burner which includes means for imparting a helical flow pattern to an influent gas stream entering a Smokestack generally axially thereof wherein the stack has inlets for additional combustion air and means such as a gas jet or the like to promote ignition of at least those portions of the combustion products passing nearest the sidewalls. The tangentially injected, higher velocity gases impart a swirling action to the slower, axially flowing combustion products, causing an overall helical combustion product flow pattern, resulting in virtually complete combustion of the products. By reason of longer dwell or residence time within the tack, higher pressures caused by centrifugal force, and higher temperatures causing combustion rate increases, greatly decreased emissions result. In one embodiment the top or outlet end of the stack is fitted with a heavy particle separator adapted to collect particulate residues, or denser gases for subsequent treatment or collection, and in most other embodiments, means are filled at the outlet end of the stack to minimize axial flow and promote helical flow therefrom.

18 Claims, 9 Drawing Figures PATENTEDum 3 m2 SHEET 1 0F 3 INVENTOR JOE W VON BRIMER ATT'YS.

PATENTEDum I972 SHEET 3 BF 3 INVENTOR COMBUSTION PRODUCT PROCESSING DEVICE AND MET-HOD BACKGROUND OF THE INVENTION The present invention relates to combustion product processing device, and in particular, to an apparatus adapted to treat combustion products generated in a furnace or other burner so as to cause complete combustion thereof and elimination therefrom insofar as possible undesirable emissions. Although the apparatus of the present invention is useful in other environments, it has been found particularly useful as an efficient, low cost addition to furnaces, smelters, incinerators, or other combustion devices. A particular feature of the present invention is that combustion products, emerging from furnaces or the like are treated so as to impart a rotary motion thereto within a generally cylindrical stack, for the purpose of increasing the dwell or residence time of the combustion products in the stack, for purposes or utilizing the concentrating effect of centrifugal forces for bringing about density gradients within the stack, and/or bringing about, favoring, or enhancing conditions conducive to more complete combustion. The helical pattern imparted to the flue gases or other combustion products which enter the stack or reactor body is accomplished by disposing a plurality of jets or the like through which air or gas may be directed, adjacent the combustion product inlet, and similarly locating an igniter along the periphery of the Stack sidewalls.

As a result of this configuration, the apparatus of the invention is adapted to bring about conditions favoring complete combustion of partially burned or residuecontaining combustionproducts without the use of conditions which are so extreme as to generate other undesirable emission products.

For example, common combustion products creating a pollution hazard generally include hydrocarbon emissions, that is, unburned or incompletely burned hydrocarbons such as gasoline, oil, or coal fumes or the like; carbon monoxide, which is a product of incomplete combustion; oxides of nitrogen, sometimes collectively referred to as NOX and which includes both NO and N and particulate matter such as fine fly ash or other inorganic components.

It is well known in the art of treating combustion residues that, as a theoretical matter, it is possible to eliminate all undesirable components from combustion, provided sufficient equipment and time is available to be devoted to the problem. However, reducing pollution to acceptable levels or eliminating it altogether, as a practical matter, is a problem which presents several facets. The first aspect is that of the type of material being burned in the principal 'unit, such as furnace, incinerator, smelter, or the like, or in other cases, reciprocating or rotary type heat engines. In the use of heat engines, the type of fuel being burned is generally well under control and known in advance, whereas this is not always the case with incinerators, furnaces, smelters or the like. Accordingly, in the case of devices of the latter class, it is common for a number of contaminants to be present in the efiluent or flue gas emanating from such burners.

As pointed out above, these contaminants include organic materials which have not been completely burned, particularly hydrocarbons, which even in LII minor quantities are annoying if not actually dangerous hazards. A second class of material in combustion products are partial or incomplete oxides, such as carbon monoxide. It is well known that, because of the instability of this compound, it is serious hazard to life if present in sufficient quantity. A third class of contaminant present is that of nitrogen oxides, either nitrogen oxide or nitrogen dioxide. These materials are very harmful to plant and animal life, and are found to be present in many combustion products, even though, as will be pointed out, rather extreme conditions are required to be present before such oxides are formed as a byproduct of combustion. The last principal class of combustion products which are common in flue gases is that of particulate material, such as oxides of iron, calcium, aluminum, and other inorganic materials.

Accordingly, for furnaces, incinerators, and the like to be acceptable from the stand point of minimizing the hazards of air pollution, it is necessary to insure that whatever processes are necessary to eliminate the undesirable combustion products must be encouraged and those conditions which lead to the formation of undesirable products should be eliminated insofar as possible.

Referring now to a number of factors influencing combustion, and the creation of combustion products, the first problem to be considered may be that of the rate of combustion, assuming that other conditions are present to permit combustion to take place. In this connection, it will be noted that combustion of gases is ordinarily a second order reaction, that is, the rate of combustion is usually proportional to the square of the absolute temperature rather than being merely directly proportional thereto. Accordingly, complete combustion is aided by the presence of localized high temperatures. In this connection, it will be noted that, whereas firebox or furnace air in the immediate vicinity of the primary combustion area is a necessity in the operation of a furnace to provide the oxygen necessary for combustion, the continued supply of air to a firebox has the effect of reducing the temperature therein, and, viewed in the respect of creating the highest possible temperatures for complete combustion is somewhat self defeating.

Accordingly, certain efforts in the past have been made, with varying degrees of success, to adapt the concept of an after-burner to flue gases and the like, wherein high temperature zones are utilized to permit the theretofore incomplete combustion of previously burned gases to proceed further. Ordinarily, however, after-burners have suffered from drawbacks which include the requirement for heat insulation to prevent damage to the components thereof and premature wearing out thereof.

Another factor which affects the rate of combustion, particularly of gases, where conditions for combustion are otherwise favorable, is that of pressure. As a rule, the rate of combustion or oxidation increases with the pressure present, particularly when measured as the pressure of the oxidizing or the reacting gas present. Although this phenomenon is well known in itself, for one reason or another, automobile exhaust systems, as well as chimneys or smokestacks used for incinerators or other burners are quite commonly characterized by low pressure areas, at least in relation to the pressure in the area where the combustion takes place. In other words, in an automobile engine, rapid burning is accomplished under conditions of relatively high compression and useful work is done by the expansion of heated gases which transfer their energy to mechanical motion. The exhaust system of such an engine may develope a certain amount of so-called back pressure, but the actual pressure in the exhaust pipe, as a rule, is of no measurable significance, since considerable effort is made to insure that excessive back pressure is not present.

In the case of furnaces, incinerators, and the like, it is well known that a rapid passage therethrough of flue gases acts to create a vacuum, particularly in the presence of low density, heated gases. It is this vacuum or draft which helps draw in extra oxygen for combustion of the product in the furnace. Accordingly, in the prior art, it has not been either common or practical to achieve and maintain high atmospheric pressures or even low levels of vacuum in the operation of fiues, smokestacks or chimneys, particularly in elongated chimneys and the like.

A further requirement which is commonly encountered in the search for elimination of undesirable combustion by-products is a need for additional combustible materials, commonly oxygen, needed for reaction with the unburned products. Accordingly, it has sometimes been proposed to 'add to a smokestack or chminey means for introducing additional air or oxygen, although, for one reason or another, these efforts have not in practice proved generally successful in eliminating the problem of completely burned residues. It is believed that this may be accounted for in part by the additional cooling effects which result from the introduction of this air or oxygen into the stream, and to the fact that, in many cases the length of time the combustion gases are present in the stack is not sufficient to raise the temperature of the product and the oxidizer with which it will react to sufficiently high levels of pressure and temperature within this period of time. Accordingly, a shortcoming of prior art exhaust stacks, chimneys, and the like has been that the combustion product does not spend a sufficient residence time therein to complete the combustion process, even assuming conditions are favorable therefor. Naturally, pure oxygen systems, for all but specialized uses, are prohibitively expensive.

In the past, it has been attempted to alter these conditions by a number of methods which included disposing in the exhaust stream catalytic reactors or the like which would increase the burning rate of the materials in question with a beneficial effect. However, it is well known in the chemical process industries that such catalysts are sensitive to poisoning by a number of materials, including heavy metals. This problem is particularly acute in the case of internal combustion engines using leaded fuels, and in the case of incinerators, smelters or furnaces, the fact that a wide variety of materials not subject to previous control are burned is a factor which further complicates the problem. Therefore, although catalysts are useful under proper conditions with the present invention, the approach of placing a catalytic reactor in an effluent exhaust stream has not always proved economically feasible for these and other reasons.

Other methods and apparatuses for reducing undesirable products in flue gases and the like have been proposed and used with varying effect, but each of the heretofore proposed methods and apparatuses, to my knowledge, has been characterized by at least one or more shortcomings sufficient to prevent economically justifiable and hence widespread adoption and use.

Accordingly, in view of the shortcomings of the prior art, it is an object of the present invention to provide an apparatus and method for reducing or eliminating undesirable products from combustion product streams.

A further object is the provision of an apparatus and method which is adapted to reduce the production of nitrogen oxides present in an effluent combustion stream, particularly relatively stable, undissociated forms of nitrogen oxides.

A further object of the invention is the provision of an air pollution control system which includes a specially designed exhaust stack having means therein for imparting a desired flow pattern to the combustion products passing therethrough.

Another object is the provision of a specially constructed exhaust stack having means for admitting combustion products thereto in a generally axial direction and for introducing additional air or combustible material therein substantially at a tangent to the cylindrical walls of the stacks.

A still further object is the provision of an apparatus wherein gas and air jets are provided adjacent the combustion gas inlet end to induce a vortical or helical flow path in the combustion gases passing therethrough.

A still further object is the provision of a combustion device which includes, at the exit end thereof, means for directing exiting gases therefrom in a generally radial or tangential pattern rather than a generally axial pattern.

Another object is the provision of a combustion product stack which includes associated therewith and generally adjacent the exit, means for passing certain elements of the combustion product from the stack to a separator along a path lying generally tangent to the cylinder forming the stack.

Another object is to provide a combustion product stack which includes means adjacent the outlet end thereof for collecting certain portions of the effluent stream and for permitting the remaining portions thereof to pass outwardly from the stack.

A still further object is the provision of an apparatus having at least some of the foregoing characteristics and being readily adaptable for use with auxiliary combustion product purifying equipment.

These objects, and other inherent objects and advantages of the invention are achieved by providing a processing device having a generally cylindrical reactor body, means for receiving combustion products at one end and discharging them at the other, means for imparting a high velocity, generally helical path to at least a portion of the combustion products during their passage through the body and means for causing or maintaining continuing ignition of at least those portions of the products near the side walls of the reactor body, whereby the combustion products are subjected to an at least partially centrifugal flow pattern within the body and whereby the residence time within the reactor body is greater then such time would be in the case of merely axial combustion product flow through the body.

The exact manner in which these objects and advantages and other inherent objects and advantages of the invention are achieved will become more clearly apparent when reference is made to the accompanying detailed description of several preferred embodiments of the invention, and to the drawings, in which like reference numerals indicate corresponding parts throughout.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view, partly diagrammatic in character, showing the combustion product processing device of the invention associated in use with an incinerator or the like;

FIG. 2 is a vertical sectional view similar to FIG. 1, showing a modified form of the processing device of the invention;

FIG. 3 is a fragmentary vertical sectional view of a portion of a further modified form of the processing device of the invention;

FIG. 4 is a fragmentary vertical sectional view showing one form of the processing device of the invention and an auxiliary combustion product processing device associated therewith;

FIG. 5 is a horizontal sectional view of the composite device of FIG. 4, taken along lines 5-5 thereof;

FIG. 6 is a vertical sectional view showing one form of collector device associated with the outlet end of a reactor body made according to the invention;

FIG. 7 is a horizontal sectional view, with portions broken away, of the collector unit of FIG. 6, taken along lines 7--7 thereof;

FIG. 8 is a vertical sectional view of a further modified processing device of the invention showing an incinerator and a control mechanism associated therewith; and

FIG. 9 is a vertical sectional view taken on lines 9-9 of FIG. 1, showing the arrangement of inlet tubes for the reactor body.

The present invention will be described with reference to a number of embodiments wherein the processing device is associated in use with a furnace, incinerator, smelter, or the like, although it is clear that the apparatus is useful with other forms of devices producing combustion products of all types. Accordingly, in the forms described, the combustible gases normally, although not necessarily, enter the processing device at a low velocity generally axially of the device, and depend on the addition thereto of other gases in a predetermined pattern in order to induce the flow patterns which are characteristic of the invention. Thus, the described embodiments show the reactor body in the form of a generally vertically extending stack or chimney, although this is not per se a necessary feature of the invention.

Referring now in greater detail to the drawings, FIG. 1 shows that the processing device includes a generally vertically extending reactor body 22 associated in use with a furnace 24 or the like, in which materials schematically represented at 26 are being burned with the aid of a stream of gases schematically represented by the arrows 28. Upon exposure to the material 26 at sufficiently elevated temperature, the

gases 28 cause combustion thereof. The reactor body 22, has generally cylindrical side walls 30, an inlet end 32, an outlet end 34, a plurality of supply means 36 for directing additional combustion air into the body 22 by way of associated ports 38, and a supply tube 40 for introducing a gas flame through an associated port 40.

Whereas the inlet end 32 may be merely an open cylinder, the outlet end 34 has means in the form of a cover plate 44 having radial or tangential outlets 46 so as to prevent unobstructed axial flow from the outlet end 34.

Referring now to FIG. 9, it will be seen that preferably, the supply tubes 36 for the combustion'air are about equally spaced apart about the exterior of the side walls 30 and are disposed at a tangent to the side walls 30 of the reactor body 22 so that combustion air passing into the body is directed in a circular path. Likewise, the supply 40 for the gas flame is similarly directed, these arrangements of the elements being made for reasons which will presently appear.

In the use of this form of the invention, a combustible material 26 is burned in a conventional manner, and as generally indicated by the direction of the arrows 28, gas flow into the reactor body 22 in the region of the inlet 32 is generally axially thereof. However, air is supplied and injected at very high velocity through the openings 38 into the reactor body near the inlet end 32 thereof. This action imparts a swirling, turbulent pattern to the gases 28 passing into the reactor body, resulting in an overall helical flow pattern and as a result, their residence or dwell time in the body is greatly increased. As an inherent result of the helical or vortical flow pattern, centrifugal force causes the denser gases and particles to be concentrated near the side walls 30 of the reactor body 22, and causes a pressure rise in this portion of the body. As a further result, the rate of combustion tends to be increased, the time for completing combustion is decreased, and, by reason of the higher dwell or residence time, the denser or unburned gases which are the source of pollution or contamination are concentrated in those areas where more complete combustion thereof is favored.

The ignition of those gases not already undergoing combustion is assured by the presence of one or more igniting means, which are present in this embodiment in the form of the flame supply 40 and the port 42 permitting communication between the flame supply and the reactor body 22. In the illustrated form, the jet of flame is also injected at a tangent to the side walls 30, so that the areas closest the side walls are certain to be contacted by the flame and so as to assist in impelling the gases in the desired helical flow pattern. The provision of the additional ignition means insures that temperatures are high enough to initiate the combustion of unburned or incompletely burned materials without disrupting the flow pattern established by the tangential injection of air. Thus, before the mixture is swirled, the concentration of some elements may be too low to support combustion, whereas, after concentration by centrifugal action, the gases may present a combustible concentration.

The provision of the top plate 44 and, one or more radial or tangential outlets 46 insures that, to the greatest possible extent, the gases maintain the helical flow path, since no gases tending to flow axially without a substantial radial component are permitted to flow out the end of the reactor body without a change of direction. As a result of the foregoing construction features, greatly increased combustion takes place, since the residence time of the gases in the stack is increased, the pressure is increased by reason of the centrifugal force, sufficient additional air is added to provide complete combustion, and an ignition flame is provided to initiate combustion not already in progress, while the cylindrical form of the reactor body and the provision of the cover plate 44 and the radial outlets 46 tend to continue the helical flow pattern already established in the reactor body. 7

Referring now to FIG. 2, a similar embodiment is shown wherein a combustion gas processing device or unit a associated with a furnace 240 includes cylindrical side walls a forming the body 22a of the reactor, with means 36a, 40a being provided to supply additional combustion air and a gas jet flame or other ignition means respectively through ports 38a, 42a. A top cover 44a having radial or tangential outlets 46a is provided for the outlet end 34a of the reactor body 22a; however, in this embodiment, an axially extending inner sleeve 48a is also provided to permit additional air to enter the center core of the reactor body 22a generally axially thereof, as shown by the directional arrows 50a. In this form of the invention, the inner sleeve 48a which extends into the central, low pressure area of the reactor body 22a also serves as a guide to assist in maintaining the centrifugal flow pattern and to provide a passage for directing additional combustion air into the central low pressure area generally adjacent the inlet end 32a of the reactor body 22a. Such an arrangement may also be used to maintain control over excessively high stack temperatures.

Referring again to the embodiments of FIG. 2, it will also be noted that an annular plate or collar 33a is shown to extend around the inside surface of the side wall 30a just beneath or upstream of the ports 38a through which the additional supply of combustion gases enter the reactor body 22a One principal purpose for this collar 33a is to assure that the direction of progress of the helix of swirling combustion products is toward the outlet end 34a of the body 22a rather than in a reverse direction. This feature may be provided in any of the various forms of the reactor body, if desired.

Referring now to the feature of providing means to initiate or continue combustion of the gases, the illustrated embodiments show means for supplying and directing a gas jet flame into the interior of the body 220 for this purpose. However, it will be understood that the same function may be accomplished by the use of other ignition means. For example, one or more electric spark plugs or the like may be inserted in one or more openings such as openings 42 and discharged intermittently or continuously in order to provide postignition or to aid in continuing ignition. Similarly, glow plugs or hot wire filaments may be used for this purpose. In addition, ignition may be initiated or continued by the use of catalytic means rather than by the use of high temperatures, sparks, or flames. Thus, catalysts of the types commonly used in afterbumers or similar reactor systems may also be used in the present invention in place of the gas flame or its equivalent.

Referring now to FIG. 3, another means for controlling and/or preventing undesired gas flow into the center of the reactor body and for preventing direct axial flow of combustion products from the outlet end 34b of the reactor body 22b are shown to be present in the form of an inverted, generally bell shaped baffle 52b having the tip portion 54b thereof extending axially into the outlet end 34b of the reactor body 22b. Outlets 46b are provided for permitting radially or tangentially directed outward flow from the radially outer portions of the outlet end 34b of the body 22b. In FIG. 3, which is partly diagrammatic, only a single supply means 36b for additional gases and a single tube 40b for supplying a jet flame or other ignition means are shown in detail, although it will be understood that two, three, or more of either or both of these elementsmay be provided, if desired. It will also be understood that a sleeve such as the sleeve 48a of FIG. 2 may extend downwardly through the tip 54b of the baffle 52b into and generally axially of the body 22b defined by the cylindrical side walls 30b.

The advantage of the form of construction shown in FIG. 3 is that, in use, the transition in gas flow direction is gradual rather than abrupt adjacent the outlet 34b. In most cases, the form of cover plate 44b shown in FIG. 3 is preferred, although the other forms shown are simpler, less expensive, and do function effectively.

Referring now to FIGS. 4 and 5, there are shown two views of a processing device 200 wherein the body 22c has associated therewith a separator 56c in the form of a generally cylindrical body 58c having a generally conically shaped lower portion 60c terminating in an outlet tube 620 which communicates with the outlet 640 of the lower portion 60c. The upper portion 66c of the body 58c is closed by an end plate 68c, while an entrance area 700 to the separator 56c opens into a generally rectangular duct 72c also having a reactor body entrance area 740 communicating with a portion of the upper end 340 of the reactor body 22c. The duct 72c tangentially joins both the body 58c of the separator 56c and the body 22c of the processing device 20c. A reactor body top cover plate 44c having radial or tangential outlets 46c is also provided, as in the other embodiments.

In the use of the form of apparatus shown in FIGS. 4 and 5, the separator 56c may be in a form similar to a so-called cyclone separator, and accordingly, material entering the separator 560 is also subjected to a generally centrifugal flow pattern with the result that the more dense particles pass to or remain adjacent the side wall of the separator body 58c, thence passing downwardly through the cone area 600 to the tube 62c from which they pass to an outlet 76c for collection or further treatment. The matter which is of a density such that it does not readily pass vertically through the full height of the reactor body 22c under conditions of combustion is easily collected in the separator 560, whereas the lighter gases tend to remain within the body 22c for passage out the exits 460. Accordingly, a substantial amount of particulate matter or dense gaseous matter, which is in effect refluxing in the body 22c, will pass into the separator 560, which will maintain a certain back pressure characterized at least in part by the density of the gases entering the separator 56c. In the illustrated embodiment, the duct 720 is shown as having relatively great heightin relation to the height of the stack or reactor body 22c, but it will be understood that the dimensions of this duct may be determined according to known principles so as to serve best the particular parameters of the system in which it is being used. As is also well known, the separator 56c may have associated therewith a washer or scrubber system of a well known type. 3

Referring now to FIGS. 6 and 7, another form of separator 56d is provided for the outlet end 34d of a reactor body 22d having a cover plate 44d and radial or tangential outlets 46d associated therewith. As shown in FIGS. 6 and 7, a collector annulus 78d is defined by an intermediate plate 8011, a lower plate 82d and an end portion 84d, one part of which may be fitted with a collector tube 86d. Entrance to the collector annulus 78d for combustion gases is provided by a plurality of ports 88d, 90d, etc. extending around the side walls d of the body 22d. In use, a plurality of gaseous and particulate fractions 92d, 94d, etc. are disposed more or less closely to the side wall 30d, depending on their density. Accordingly, the more dense particles tend to pass through the openings 88d, 90d, etc. and be collected within the annular collector 78d, while the lighter density fractions pass out the exits 46d. Under proper con ditions, something of an equilibrium may be maintained, and the more dense particles having a longer residence time relatively lower in the body 22d tend to remain in the vicinity of the openings 88d, 90d, etc. for collection rather than passing out the exit area 46d.

As in the other illustrated constructions, one or more collector tubes 86d may be used to collect particulate matter for subsequent treatment. It will be appreciated that a cover plate in the form shown in FIG. 3 is also advantageously used with thisform of separator.

Referring now to FIG. 8, there is somewhat schematically shown another form of the processing device 20e wherein the furnace 24e, the body 22c and the gas and ignition supply means 366, e are provided near the inlet end 322 of the body and the cover plate 44e is disposed adjacent the outlet end 34e. In this embodiment, the collar 33c is located somewhat beneath the inlet end 32c and has extending therethrough a central sleeve 96c having an outlet end 98e and a plurality of perforations 100s in the side walls l02e thereof. Near the inlet end 104e of the sleeve 96e is a means in the form of a butterfly valve l06e or the like for controlling air or other gas flow into the sleeve 96e. In the form of device shown in FIG. 8, combustion occurs in the previously described manner, with the gases such as air or the like entering the ports 38e at a tangent to the body 22c imparting a swirling action to the generally axially entering gases 28c, with a post ignition jet flame or the like being supplied through port 42a. The swirling action thus created concentrates the particulate matter and more dense unburned gases adjacent the walls we, leaving a relatively low pressure area 108e in the center of the body 22e. Accordingly, a certain demand for additional air is created, and this demand may be satisfied by passing air through the sleeve 962 under controlled conditions. In this way, two effects can be achieved. If desired, the air supplied to the center portion 1108c of the body 222 can reduce the temperature at which combustion products are being formed so as to inhibit the production of nitrogen oxides. If this effect is desired, the movement of the valve 106e may be controlled by a mechanism of a known type schematically indicated at l10e wherein inlet air flow may be made directly or approximately directly proportional to the temperature detected within the body 22e.

In this manner, significant amounts of nitrogen oxides will not be formed, since the temperatures will not rise high enough to permit the formation thereof.

On the other hand, if, for one reason or another, the temperature is high enough to cause nitrogen oxide formation, it will be desired to permit dissociation of the nitrogen oxides into atmospheric nitrogen and oxygen, which will take place if sufficient residence time is permitted at a sufficiently elevated temperature. In such a case, maintenance of a sufficiently high temperature can be insured by means of a control such as that shown schematically at 109e, which is adapted to increase .the amount or velocity of additional combustion gases fed to the body 22c, and which also activates or increases the rate of the ignition unit 40a, so that the maximum temperature rise and residence time will be produced within the stack. Such a control l09e may be of any well known type which is adapted for inversely proportional operation in relation to the temperature inside the reactor, body 22c, that is, the lowering of combustion temperature will cause injection of more fuel and air so as to tend to raise the temperature. Thus, the controls 109e, l10e may be adapted for intentionally raising or lowering the ambient temperature within the reactor body 22e. On the other hand, the location of the openings e may be spaced axially apart from the inlet end 32e of the body 222 so that there is a significant extent of the body 22c in which combustion may take place prior to the time in the cycle when air is added, so that, although additional oxygen can be provided through the openings 100e, the temperature in the firebox area and in the inlet area 32e of the reactor body 22e may remain high enough to provide a rapid burning rate.

It will also be appreciated that, as the apparatus 20e is used under varying conditions, varying pressures within the body 22e, and particularly within the center 108a thereof, will occur. Accordingly, the mechanism llOe for regulating the valve or damper l06e may be pressure sensitive, or temperature sensitive or both. A simple example of pressure control may be merely counterweighting the damper or valve 106e to a normally closed position and allowing differential pressures outside and inside the sleeve 96c to open or close the valve l06e to a greater or less extent.

The form of processing device shown in FIG. 8 is particularly advantageous for use where metals are to be melted or roasted, particularly impure metals which are to be reclaimed but which have associated therewith organic materials such as rubber, plastics, cloth, or the like. In such a case, it is desired to maintain high temperatures within the furnace or firebox area 24e and to prevent entry of so much air as to cause low roasting or burning temperatures, but it is desirable to provide additional oxygen to complete the relatively slow burning of the organic materials referred to above. Thus, in use, the apparatus has proved effective to eliminate dense, black smoke which emanated from other prior art forms of similar apparatus, and which reflected conditions wherein the combustible mixture was so rich as to create dense smoke but not rich enough to be burned at the temperatures and pressures which could be achieved under the burning conditions provided with such prior art units.

Referring now to features common to all of the particularly described embodiments of the invention, and other embodiments thereof which will be apparent to those skilled in the art, one such feature is that the gases to be processed in the reactor body enter the reactor body generally axially thereof at a relatively low velocity. Although the entry of the gases in an axial direction is not per se a necessary or even a desired feature of the invention, the present invention is useful with gases whose existing velocity is low enough so that a great deal of acceleration cannot be imparted thereto merely by directing them in a circular or helical path and relying on their velocity or other energy to impart the rapid swirling action thereto which is necessary. Accordingly, the swirling centrifugal or rotational flow patterns are imparted to the gases by addition thereto of high velocity tangential jets of air or other gas which preferably form a combustion product with combustion product gases which are already in the reactor body. In this connection, it will be observed that the present invention is herein described with reference to systems wherein the combustion products occur by reason of oxidation, and wherein air is used as the oxygen source. However, any partial or complete gas phase reaction may be carried out in this apparatus, such as a reducing reaction, an oxidizing reaction using oxygen or other oxidizing element or compound, e.g. chlorine, etc. or other gas phase reaction.

Another common feature is that, by reason of the high velocity flow imparted to the generally axially moving gases, the combustion products are in a state of great turbulence or as sometimes stated, they are characterized by a high Reynolds number. This turbulent condition is favorable to more complete combustion, since, among other things,adjacent laminae of gases tend to be mixed with each other to increase the speed of propagation of the flame front through the material.

Another common feature is that a more dense mixture of combustible materials can be achieved because of the centrifugal action imparted by the tangential air injection. The centrifugal force fields tend to increase the pressure adjacent the side walls of the reactor, where most of the combustion occurs, with the result that the combustion rate is increased.

It is also thought possible that the compression brought about by the centrifugal force may be at least in part an adibatic compression of the gases, causing somewhat higher temperatures. In this connection, it will be observed that even slight increases in temperature are beneficial because reaction times of certain of the reactions in question are proportional to the square of the temperatures rather than merely directly proportional to the temperatures themselves. Although, no particular theory or mode of operation forms an essential part of the present invention, it is believed that these very favorable results were achieved by reason of imparting to the combustion products the helical flow characteristic of the invention to provide increased residence time within the reactor body density and temperature gradients suitable for concentrating combustible gas and particulate mixtures in the presence of adequate air and in the presence of an ignition means, while bringing about conditions of temperature, pressure and turbulence favorable to sustaining the complete combustion of gases. At the same time, the low pressures in the central area of the reactor body were utilized, where necessary, to draw in additional combustion air, in some cases, under controlled conditions for complete combustion. Where relatively great product density gradients exist within the stack or reactor body, the auxiliary separators have been found effective to perform preliminary or simple separations of this material from the combustion products.

At any rate, although the invention does not depend on any particular theory or principle of operation, and although it is not known with certainty whether or not any of the foregoing effects are fully or partially responsible for the advantages of the invention, it is known that processing devices constructed according to the present invention have been effective to reduce pollution emanating from burning devices such as incinerators, furnaces, smelters and the like. For example, in reclaiming metal scrap having bonded thereto and associated therewith a substantial amount of rubber and plastic material, furnaces with ordinary smoke stacks created dense, opaque black smoke which was violative of local codes and which contained hydrocarbon and particulate residues in great amounts. However, when equipped with a processing device such as one of those described herein, the hydrocarbon content of the combustion products was very greatly diminished, and the smoke resulting from burning the same products was practically invisible and free of particulate matter.

It will thus be seen that the present invention provides novel processing apparatuses and methods having a number of advantages and characteristics, including those pointed out above and others which are inherent in the invention.

I claim:

1. A combustion product processing device comprising, in combination, a reactor body defined at least in part by generally cylindrical, axially extending side walls, a combustion product inlet end, means disposed adjacent said inlet end for permitting combustion products to flow into said reactor body at a relatively low velocity, an outlet end, means adjacent said inlet end for directing additional combustion product-forming gases into said reactor body at a relatively high velocity substantially at a tangent to said side walls and directed generally perpendicular to the axis of said body, means for causing combustion product forming gases in said body to be ignited while said gases are in the portion of the body generally adjacent said side walls, and means for controlling the flow of additional gases into the radially central area of said reactor body, whereby combustion products entering said inlet of said chamber will be subjected to forces tending to cause said products to move in a helical path within said body to lengthen the flow path and residence time of said products within said body and to subject said products to an at least partially centrifugal flow pattern within said body.

2. A processing device as defined in claim 1 wherein means are provided for causing said low velocity incoming combustion products to enter said body generally axially thereof.

3. A processing device as defined in claim 1 in which said means for controlling said flow of additional gases comprises means at least partially closing off the radially central portion of said outlet end to prevent axial gas flow into said central area.

4. A processing device as defined in claim 1 in which said means for controlling the flow of said gases comprises a cover plate for the outlet end of said reactor body, said cover plate permitting radial and tangential flow from the outlet of said reactor body, said plate also having a portion thereof extending axially into said reactor body generally centrally thereof and co-axial therewith.

5. A processing device as defined in claim 1 which further includes means adjacent said inlet end and surrounding the radially outer portions of said body to prevent axial gas flow in said portions of said body opposite the direction of gas flow towards said outlet end of said body.

6. A processing device as defined in claim 1 in which said flow control means extends generally centrally of said body and parallel to the axis thereof, and has means thereon for permitting additional gases to flow into said reactor body under controlled conditions for further combustion with the combustion products therein.

7. A processing device as defined in claim 1 in which said means for directing said additional combustion product forming gases includes a plurality of tubes of very small diameter in relation to the diameter of said reactor body.

8. A processing device as defined in claim 1 which additionally includes means associated therewith for separating combustion products passing through said reactor body by density gradients.

9. A processing device as defined in claim 1 wherein said reactor body has associated therewith, near the outlet end thereof, a separator, said separator comprising a generally cylindrical tube having one end thereof closed off, and wherein a duct is provided extending between said reactor body and said separator, said duct having inlet and outlet openings disposed respectively tangentially of said reactor body and said separator.

10. A processing device as defined in claim 6 in which said flow control means is operable in response to the temperature within a portion of said reactor body.

11. A processing device as defined in claim 6 in which said flow control means is operable in response to the pressure within a portion of said reactor body.

12. A processing device as defined in claim 6 in which said fiow control means is adapted to receive additional gases from the exterior of said reactor body and to direct said gases into said reactor body in a recenter of said reactor body.

14. A processing device as defined in claim 13 in which said outlet means comprises a plurality of openings spaced axially apart in said reactor body.

15. A method of processing gaseous combustion products comprising introducing said products into one end of a defined zone at a relatively low velocity, directing additional combustion product forming gases at said products at a high velocity and at a tangent to said zone to impart a helical flow to said products whereby said products are swirled rapidly within said zone and are moved axially thereof toward a zone outlet at the other end of said defined zone, to cause increased residence time of said products within said zone in relation to the residence time in said zone which would be achieved by said products with substantially only axial flow of the same velocity.

16. A method of defined in claim 15 which further includes providing a continually operative ignition source within said zone adjacent an outer periphery thereof and adjacent the point at which said additional combustion product forming gases are directed into said zone.

17. A method of processing combustion products comprising directing said products into a confined zone at a low velocity, subjecting said products to tangential attack by additional combustion product forming gases at high velocities to impart a substantial circumferential component of movement to said products, establishing density and velocity gradients within said mass of combustion products, and causing continuing ignition of said products at least in the regions of higher density to provide increased combustion of said products at least in said high density areas.

18. A method of processing gaseous combustion products comprising introducing said products into one end of a defined zone at a relatively low velocity, and directing additional combustion product forming gases at said products at a high velocity and at a tangent to said zone to impart a helical flow to said products I whereby said products are swirled rapidly within said zone and are moved axially thereof toward a zone outlet at the other end of said defined zone, to cause increased residence time of said products within said zone in relation to the residence time in said zone which would be achieved by said products with substantially only axial fiow of the same velocity, while preventing axial flow of said gases outwardly from said confined zone and permitting radial flow from the outlet of said confined zone in the areas thereof adjacent the radially outer periphery of said zone.

Claims

12. A processing device as defined in claim 6 in which said flow control means is adapted to receive additional gases from the exterior of said reactor body and to direct said gases into said reactor body in a region adjacent the inlet end thereof.

13. A processing device as defined in claim 6 in which said flow control means includes a tube extending generally co-axially of said reactor body in the center thereof, said tube having an inlet means outside said reactor body and outlet means generally within the center of said reactor body.

18. A method of processing gaseous combustion products comprising introducing said Products into one end of a defined zone at a relatively low velocity, and directing additional combustion product forming gases at said products at a high velocity and at a tangent to said zone to impart a helical flow to said products whereby said products are swirled rapidly within said zone and are moved axially thereof toward a zone outlet at the other end of said defined zone, to cause increased residence time of said products within said zone in relation to the residence time in said zone which would be achieved by said products with substantially only axial flow of the same velocity, while preventing axial flow of said gases outwardly from said confined zone and permitting radial flow from the outlet of said confined zone in the areas thereof adjacent the radially outer periphery of said zone.