JP3711086B2 - Venturi cluster, burner apparatus and method of using the cluster - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a venturi tube in which another fluid flow is induced when a fluid induced flow passes through. The invention further relates to an industrial burner that induces the flow of one or more components of the combustible mixture to form a mixture for introduction into the combustion zone. The invention also relates to a burner device capable of forming and handling an oxygen-rich combustible mixture.
[0002]
[Prior art]
Venturi devices that induce the flow of another fluid (induced fluid) by the flow of one fluid (guide fluid) are known. These devices are generally constituted by an inlet end, a throat and an outlet end. Generally speaking, the throat has a smaller flow area than the inlet end, thus providing a low pressure area for the throat. The induced fluid flows from the inlet end of the venturi tube through the tube, and the source of the induced fluid is in fluid communication with the low pressure region formed at the throat of the device by the flow of the induced fluid. Thus, the fluid to be introduced is drawn into the throat and mixed with the induction fluid.
[0003]
Venturi devices are used where fluid fuel induces an air flow to form a fuel and air mixture in the venturi tube. However, it may also help to direct fuel flow using combustion air. In another example, the flow of air or fuel through a venturi tube is used to induce a flow of recirculated flue gas or other diluent to control flame temperature or affect the production of nitrogen oxides. You can also.
[0004]
Despite its widespread use, the Venturi tube has certain limitations. First, the venturi's ability to draw a flow of induced fluid is limited by the available pressure of the induced fluid and its amount required for a given application. Furthermore, the effective venturi length is directly related to the throat diameter. Thus, the physical dimensions of the work environment have a limited impact on the venturi capacity.
[0005]
In a broader sense, the reduction and / or reduction of nitrogen oxides in industrial burners is always a desirable objective. Previously, it was possible to reduce nitrogen oxides to some extent by using a portion of the gaseous fuel in conjunction with the primary combustible fuel / air mixture in a stepwise manner. A thin primary mixture of fuel is often desirable in certain applications because excess air is added to lower the flame temperature and reduce nitrogen oxides. The gas is then introduced into the combustion zone stepwise from a gas tip disposed stepwise around the burner or a central gas tip extending through the center of the downstream end of the burner nozzle. Secondary fuel burns in an environment where flue gas is available as a diluent. This configuration did not necessarily reduce the nitrogen oxides to the desired level.
[0006]
In one example, the excess mass provided by excess air introduces a thin primary mixture of fuel into the combustion zone at a relatively high rate. This speed sometimes leads to an unstable flame condition where the flame speed becomes too high.
[0007]
[Problems to be solved by the invention]
In accordance with the principles and concepts of the present invention, in one important aspect, a composite venturi structure is provided that includes a venturi cluster of a plurality of venturi tubes. In accordance with an aspect of the invention, a composite venturi structure is defined as having at least two venturi tubes. Desirably, the structure has at least three, sometimes six, venturi tubes, and in certain applications may have six or more venturi tubes. An important object of the present invention is to actually solve the problems still present in the burner field, in particular the problem of high levels of nitric oxide. That is, the present invention provides an apparatus and method that solves and eliminates the aforementioned problems. Furthermore, the present invention solves the problems generally associated with Venturi tubes. By providing a plurality of venturi tubes, the surface area is increased, so that a greater flow of induced material can be drawn with a given volume of induction fluid. Further, for a given flow of inductive fluid, the venturi throat in the bundle has a small throat, thus reducing its length.
[0008]
[Means for Solving the Problems]
Each Venturi tube of the cluster has an inlet, a throat, and an outlet, and is arranged and configured to cause a flow of the induced substance by passing the induction fluid. In each Venturi tube, this action forms a respective mixture of induced material and induced fluid, which mixture is then discharged from each Venturi tube. The structure preferably also comprises a collector having an inlet end connected to and in fluid communication with the outlet of the venturi tube. Thus, each of the mixture of the induced fluid and the induced substance discharged from the outlet is collected and mixed with each other to be discharged as a single mixed flow from the outlet of the collector. The induced material is often a fluid material. However, according to the broad aspect and intention of the present invention, the induced substance may be a flowable solid substance such as a powder or flaky substance.
[0009]
The venturi tube of the composite venturi structure of the present invention is not essential, but is preferably an elongated and basically straight tube. Although not essential, it is desirable that the tubes be arranged essentially parallel to each other. Although this Venturi tube has essentially the same physical capabilities, this is not an essential or important feature of the present invention, in fact, at least one of the Venturi tubes in a given cluster is the same cluster. There are many applications where it is desirable to have different physical capabilities than other Venturi tubes within.
[0010]
In another important aspect of the present invention, the composite venturi structure is a component of a novel burner assembly. In accordance with this aspect of the invention, in addition to the venturi cluster and collector, the burner assembly includes a burner tip attached to and in fluid communication with the outlet end of the collector. Thus, the tip is arranged to receive a single mixed flow of fluid from the collector and direct it toward the combustion zone.
[0011]
In one important embodiment of the present invention, the tip is elongated and configured and arranged to direct a single mixed stream exiting the tip toward the combustion zone substantially radially with respect to the longitudinal axis of the tip. . The tip is preferably configured to form a round flat flame surrounding the tip.
[0012]
In another important embodiment of the present invention, the tip is elongated and is configured and arranged to direct a single mixed stream exiting the tip toward the combustion zone approximately axially relative to the longitudinal axis of the tip. Yes. The tip is preferably configured to form a cylindrical flame extending along the axis.
[0013]
In general, either gaseous fuel or air is the inducing fluid, but it is desirable that at least one of the venturi tubes be constructed and arranged to operate with the gaseous fuel as the inducing fluid. When gaseous fuel is used as the guiding fluid, either air or recirculating flue gas is the induced fluid. Desirably, at least one Venturi tube is constructed and arranged to operate with air as the inductive fluid. Thus, when gaseous fuel is used as the guiding fluid and air is the induced fluid, the single mixed stream formed by the collector will contain a mixture of fluid fuel and air. Similarly, if gaseous fuel is used as the guiding fluid and the recirculating flue gas is the induced fluid, a single mixed stream will contain a mixture of fluid fuel and flue gas. For some applications, gaseous fuel is used as an inductive fluid to direct the flow of air into one venturi tube of a given cluster, and the flue gas in another venturi tube of the cluster To guide the flow. Thus, a single mixed stream will contain a mixture of fluid fuel, air and recirculating flue gas. One or more Venturi tubes in the cluster are constructed and arranged to operate with a diluent as the induced fluid so that a single mixed stream includes fluid fuel and diluent. The diluent is an available gas, such as steam, nitrogen, carbon dioxide, which is inert to the combustion reaction process.
[0014]
According to an important aspect of the invention, the collector is preferably elongated and arranged with a central axis extending between its ends. The assembly also preferably comprises a central fuel tube extending through the collector along the collector axis. Ideally, the central fuel tube has a downstream end portion extending through the burner tip and protruding through an opening located in the center of the downstream end of the burner tip. According to a preferred embodiment of the present invention, the assembly comprises a fuel nozzle located at the downstream end portion of the central fuel tube.
[0015]
Ideally, the inlet end of the collector comprises each open segment for each venturi tube of the cluster, and the venturi tube outlet is connected to each segment. The segments extend around the central fuel tube as a set so that the mixed flow is evenly distributed within the collector. The fuel nozzle burns secondary fuel when the tip is configured and arranged to direct a single mixed stream exiting the tip toward the combustion zone approximately radially with respect to the longitudinal axis of the tip. It is desirable to be configured and arranged so as to supply to the area. On the other hand, if the tip is configured and arranged to direct a single mixed stream exiting the tip toward the combustion zone approximately axially with respect to the longitudinal axis of the tip, the fuel nozzle It is desirable to be constructed and arranged so as to provide a continuous primary flame at a position in an area axially separated from the downstream end. In the latter case, the fuel nozzle is ideally provided at a position sufficiently away from the downstream end of the tip of the combustion zone, and when the single mixed flow approaches the fuel nozzle, the speed does not become higher than the flame maintenance speed. In this way, the single mixed stream expands to reduce the speed.
[0016]
In another aspect, the present invention provides a burner assembly with a burner tube structure that includes one, but not necessarily, one or more venturi tubes. However, the burner tube structure comprises an elongated burner conduit having an inlet end and an outlet end that are spaced apart from each other. This conduit may be a venturi tube. In another example, this may be just a hollow tube or pipe. This conduit is constructed so that a combustible gas mixture containing fluid fuel, preferably in the form of a gaseous fuel, and oxygen, preferably in the form of air, is directed from its inlet end to its outlet end along it. Has been placed. In accordance with this aspect of the present invention, the outlet end of the conduit is provided with a burner tip, which preferably has a central axis and a downstream end spaced from the outlet end of the conduit. The tip is arranged and configured to receive the combustible mixture from the conduit and direct it through the one or more holes at the downstream end of the tip toward the combustion zone in a direction along the tip axis.
[0017]
The assembly of this aspect of the invention further comprises an elongate central fuel tube extending through the tip along the axis. The fuel tube preferably projects axially out of the tip through the downstream end of the tip, and the fuel tube has a downstream end portion located in the combustion zone away from the downstream end of the burner tip. A hole at the downstream end of the tip is located around the fuel tube so that the mixture toward the combustion zone extends out of the downstream end around the fuel tube and along the axis toward the downstream end portion of the fuel tube. It is almost cylindrical. Ideally, the assembly includes a fuel nozzle at the downstream end portion of the fuel tube located in a location sufficiently far from the downstream end of the burner tip, and expands after the mixture leaves the downstream end of the tip. Thus, it is decelerated to a speed lower than the flame speed before it reaches the vicinity of the fuel nozzle. In this form of the invention, the burner assembly is suitable for use in situations where the combustible mixture is comprised of a very thin fuel and air mixture.
[0018]
According to the concept and principle of the present invention, the burner tip is provided in a substantially dome shape. The novel burner tip of the present invention has a generally ring-shaped base portion having a central axis and elongated, side-by-side, circumferentially spaced extensions extending in a direction along the axis. And ribs curved in the longitudinal direction. Each of these ribs has a first end attached to the base and a second end spaced from the base, the second end being located closer to the shaft than the first end. Together, the base portion and the ribs form a region configured to receive a flow of air and fluid fuel mixture inside the tip, the ribs forming curved slots on their own, The mixture is allowed to flow out from the inner region of the chip through both in the radial direction and in the direction including the vector extending along the axis. In accordance with the present invention, the burner tip includes a crown-shaped portion connected to the second end of the rib, the crown-shaped portion including a plurality of discontinuous portions extending axially and radially aligned with each slot. In particular, the air / fluid fuel mixture passing through the discontinuity is configured to have a more significant axial flow relative to the air / fluid fuel mixture flowing through the slot. These discontinuities are preferably positioned to flow the air / fluid fuel mixture therethrough and form a pre-stage mixing zone outside the combustion zone. The crown-shaped portion also has a gas nozzle receiving opening aligned in the axial direction.
[0019]
In one preferred embodiment of the present invention, the tip described above is used in combination with a burner assembly having a composite venturi structure as described above.
[0020]
The present invention also provides a method for enhancing the ability of a venturi device to direct a second fluid flow to the first fluid as the first fluid flow passes through the device. The method separates the first fluid into at least two, preferably at least three, and possibly six or more diverted portions, each of the diverted portions of the first fluid being passed through each Venturi tube, Are separately guided to each of the diverted portions, thereby forming an individually diverted mixture of the first and second fluids, and mixing these individually diverted mixtures through a single venturi tube. A mixture of first and second fluids is formed that includes a second fluid at a higher concentration than would be obtained by flowing the entire amount of the first fluid. According to the present invention, the first fluid is preferably a gaseous fuel and the second fluid is preferably air.
[0021]
The present invention further provides a method for reducing the length of a venturi device configured to direct a second fluid flow to the first fluid as the first fluid flow passes through the device. In this aspect of the invention, the method separates the first fluid into at least two, preferably at least three, and possibly six or more diverted portions; each diverted portion of the first fluid is connected to each Venturi tube. Passing the second fluid stream separately into each of the first fluid diverted portions thereby forming a mixture of the first and second fluids; mixing each of these diverted mixtures to the same length Forming a mixture of the first and second fluids, including a concentration of the second fluid that is higher than would be obtained by flowing the entire amount of the first fluid through a single Venturi tube.
[0022]
In addition, the present invention provides a method of operating a venturi device, providing at least two venturi tubes, each venturi tube having an inlet, a throat, and an outlet, each of which is covered as the guiding fluid passes through it. A flow of inducer is caused, thereby forming a mixture of induced material and inducer fluid, the mixture is discharged from its outlet, and the first inducer fluid is passed through the first venturi tube, thereby Of the first induced fluid to form a first mixture of the first induced fluid and the first induced material, discharging the first mixture from the outlet of the first venturi; A second venturi tube, thereby causing a flow of a second induced material to form a second mixture of the second induced fluid and the second induced material, and the second mixture is It discharged from the outlet of the tube; and in mixtures with one another attracting first and second mixtures to form a single mixed stream comprising said fluid and material.
[0023]
The present invention further provides a method of operating a burner comprising a venturi device for supplying a combustible mixture to a burner nozzle, the burner comprising at least two venturi tubes, each venturi tube being an inlet, Each having a throat and an outlet, each of which induces a flow of the induced fluid as the guiding fluid passes through it to form a mixture of the induced and guiding fluids and discharges the mixture from the outlet Passing a first induction fluid through the first tube of the Venturi tube, thereby inducing a flow of the first induced fluid to form a first mixture of the first induction fluid and the first induced fluid, Discharging the first mixture from the outlet of the first venturi tube; passing a second induction fluid through the second tube of the venturi tube thereby inducing a flow of the second induced fluid; And a second induced fluid is formed, the second mixture is discharged from the outlet of the second venturi tube; and the first and second mixtures are collected and mixed together to produce a simple mixture of the fluids. A combustible mixed stream is formed. Ideally, the first and second induced fluids are each gaseous fuel, and the first and second induced fluids are each air. In another example, the first induced fluid is air and the second induced fluid is a recirculating flue gas or an inert gas such as steam, nitrogen, carbon dioxide, or other diluent.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a number of novel features that can be combined or used alone. In particular, these features are useful in connection with a burner and / or burner assembly configured to burn fluid fuel. The fluid fuel may be a fuel oil or the like, but is preferably a gaseous fuel such as natural gas, propane, butane, or hydrogen.
[0025]
One burner assembly embodying the principles and concepts of the present invention is shown at 20 in FIGS. The burner assembly 20 includes a generally cylindrical outer shell 22 and a set of secondary fuel nozzles 24 attached to the periphery connected to a fuel manifold 26. As seen in FIGS. 2, 4 and 5, the assembly 20 also includes a composite venturi structure 28 having a venturi cluster 30 composed of six separate venturi tubes 32. Each venturi 32 has a lower or upstream inlet 34 (similar to that shown in FIG. 2), a throat 36, and an upper or downstream outlet 38. As seen in FIGS. 2, 4, 6 and 7, the venturi inlet end portion 35 extending from the inlet 34 to the throat 36 extends outwardly and is substantially conical or bell-shaped.
[0026]
Each individual venturi tube 32 is of a conventional type of venturi structure of the type well known to those of ordinary skill in the burner art, each configured and arranged to cause a material to be induced to flow by simply passing a guiding fluid. It may be. By this phenomenon, each mixture of the induced substance and the induced fluid is formed in the venturi tube and is discharged through the outlet 38 at the downstream end of the venturi tube.
[0027]
The structure 28 also includes a collector 40 having an inlet end 42 which, as shown in FIG. 2, is connected to and in fluid communication with the outlet 38 of the venturi tube 32. Is arranged. As will be appreciated by those skilled in the art, the upper end 39 of the venturi 32 adjacent to the outlet 38 is a smooth connection between the outlet 38 and the inlet end 42 of the collector 40, as schematically shown in FIG. A suitable transition region 41 is provided. Thanks to such a configuration, each mixture leaving the outlet 38 at the downstream end of the venturi tube is collected in the collector 40 and mixed together to form a single mixed stream. In order to facilitate the intermixing action, the collector 40 includes a radially extending portion 43 as shown.
[0028]
Although the Venturi cluster is depicted in FIGS. 2, 4 and 5 as comprising six separate Venturi tubes, as will be appreciated by those skilled in the art, this cluster is arranged for parallel flow. There may be provided only two venturi tubes that have been made. Conversely, this cluster can also include 6 or more, for example, 12 or more Venturi tubes, depending on the needs of a given application.
[0029]
As is apparent to those skilled in the art, there are a variety of venturi guiding fluids. Furthermore, the induced substance is not necessarily the same. For example, in the case of a burner, the induction fluid is a fluid such as gaseous fossil fuel or hydrogen, while the induced substance is air or combustion inert gas such as recovered flue gas, steam, carbon dioxide or nitrogen It may be a diluted material. In another example, the induced fluid may be air and the induced material may be a fluid fuel or a diluent material. In any case, each mixture produced in each Venturi tube 32 is well mixed with each other at the collector 40 to form a single mixed stream, and oxide when the Venturi cluster 30 is used as a burner. , Fluid fuel and appropriate diluent material.
[0030]
In order to use the concept and principle of the present invention in conjunction with a burner, the inducing fluid is preferably a fluid, especially gaseous fuel, and the induced material is a gas, preferably oxygen containing air. desirable. For this purpose, the burner assembly 20 comprises a set of fuel gas inlet tubes 44 connected to a common fuel source not shown. The burner assembly 20 also includes a set of control handles 46, preferably one for each venturi tube 32. These handles 46 are capable of moving each control element 48 closer to and away from the inlet 34 of the corresponding Venturi tube 32 in the usual manner, thereby adding additional fluid flowing into the inlet 34 via the inlet tube 44. As a result of the pressurized fuel gas, it controls the amount of air drawn into the corresponding venturi 32 from the surrounding air box. The air box is shown schematically at 50 in FIG.
[0031]
With the configuration described above, as fuel gas is exhausted through the corresponding tube 44 into each venturi, air from the air box 50 is drawn into the inlet 34 through the gap 52 between each inlet 34 and its corresponding element 48. It is. The amount of air drawn into the inlet 34 can be controlled by varying the width of the gap 52 by raising and / or lowering the element 48 using the corresponding handle 46. This air drawn into the inlet 34 by the fuel gas flowing into the inlet 34 through the tube 44 together with the fuel gas discharged from the tube 44 forms a mixture of fuel gas and air, which passes through the venturi 32. It flows through the outlet 38 and is discharged from the venturi tube 38.
[0032]
Details of the air control device are shown in particular detail in FIGS. 6 and 7 as components of a burner mechanism consisting of three Venturi tubes. In this regard, it should be noted that the venturi tube 32, tube 44, handle 46 and control element 48 of FIGS. 6 and 7 are essentially the same as the corresponding components of the assembly 20 of FIGS. . Therefore, when the handle 46 is turned in one direction, the gap 52 widens, and when the handle 46 is turned in the opposite direction, the gap 52 narrows. The mechanism of FIGS. 6 and 7 also includes a central fuel supply pipe 70 for the purposes described below.
[0033]
Each mixture from the venturi tube 32 is collected in the collector 40 and mixed together to form a single mixed flow of fuel gas and air, which enters the burner tip 54 and burner mechanism 20 Is distributed within a combustion zone 56 that substantially surrounds the upper end 58 of the engine. As can be seen in FIG. 2, the collector 40 preferably extends in a direction along the longitudinal central axis 60 of the burner assembly 20 and is provided with a burner tip 54 at the outlet or downstream end 62.
[0034]
The Venturi tubes 32 are preferably arranged so that the flow in the cluster 30 is parallel, and each mixture formed in the Venturi tubes is fed to a common collector 40 where they are combined with each other from air and fuel. To form a single combustible premix. This premix then goes to a common premix chip 54 provided at the downstream end 62 of the collector. The premix tip 54 is configured so that the pressure inside the tip is essentially the same as the pressure that would normally appear when only one Venturi tube is used. This ensures a pressure drop associated with the same gas velocity as in the case of a single Venturi tube. The use of multiple venturi tubes allows the use of multiple gas spuds (injectors) that diffuse air into the single gas jet at the same speed. The added surface area of the three jets (or even more as needed in the application) allows a significant amount of air to diffuse into the jet. This also allows more air to accompany the venturi opening through the jet momentum. This is because the accompanying amount of the induced fluid varies depending on the surface area of the induced flow. The additional air entrained is a function of the number of gas jets used and the momentum of the gas when the gas leaves the spud.
[0035]
In one embodiment of the present invention, the Venturi cluster 30 includes six Venturi tubes 32 as previously described with respect to FIGS. In another useful form of the invention, the cluster 30 comprises two or more, three or more, or six or more venturi tubes. For example, a burner assembly using three venturi tubes is shown in FIGS. In this regard, the only limitation is that the venturi tubes of each cluster are discharged into a common collector 40 where the individual mixtures from each venturi tube are mixed together to form a single mixed stream. In the above-described embodiment, the guiding fluid is a fuel gas and the induced fluid is air.
[0036]
In a preferred form of the invention, the capacity of the individual venturi tubes is the same. However, according to the broad intent of the present invention, the individual Venturi tubes in a given cluster may not be the same. That is, the capacity of one or more venturis in a given cluster may be different from the capacity of one or more other venturis in the same cluster. Further, one or more venturi guiding fluids in a given cluster may be different from one or more other venturi guiding fluids in the same cluster. Further, the induced fluid of one or more venturi tubes in a given cluster may be different from the induced fluid of one or more other venturi tubes in the same cluster. As an example in this regard, the induced fluid of one venturi tube in a given cluster is air and the induced fluid of another venturi tube in the same cluster is flue gas or nitrogen or steam Diluted substances such as Further, as another example of the burner, the guiding fluid may be air and the induced fluid may be a fuel gas. As will be readily appreciated by those skilled in the art of burner technology, there are a vast number of Venturi tube capacities, induced fluids and induced fluids that can be usefully employed in a Venturi cluster according to the concepts and principles of the present invention. Combinations are possible.
[0037]
The number of venturi tubes to be used for a given application at a given time is determined by the heat generation of the burner and the shape of the burner suitable for that application. Very low nitrogen oxides (NO _X ), One or more venturi tubes are used to draw flue gas from the furnace, and the remaining venturi tubes are used for gas and air. The furnace flue gas is mixed in the collector 40 with the fuel and air mixture from the other venturi tubes, thus adding mass to the entire combustion stream. This increased load on the flame due to the added mass reduces the flame temperature as the reaction rate slows, resulting in less nitrogen oxide emissions. This concept, coupled with the use of a homogeneous premixed mixture of gas and air as the primary fuel element in other burner designs, successfully reduces nitrogen oxides in other types of burners, resulting in a wide range of Causes fever.
[0038]
By using a large number of venturi tubes to provide a fuel and air premix, it is possible to provide a very thin premix of fuel. Such a thin fuel premix preferably contains about 55% or less of the total amount of fuel required, while containing all the oxygen necessary to burn the total fuel. The remaining fuel is then supplied as secondary fuel through the multistage nozzle. This very thin premix concept that maintains the fuel gas to air ratio close to the lower combustion limit places the greatest load on the heat generated by the primary flame. Mechanisms with multiple venturi tubes can take advantage of the concept of using a very thin fuel premix, taking full advantage of the ability to step-by-stage fuel-rich gas flow as a multistage gas. The diluted premix gas stream combined with the fuel gas associated with the multi-stage gas jet provided a new trigger for nitrogen oxide reduction. It was observed that nitrogen oxide emissions in this burner configuration had dropped to 3 ppm by volume.
[0039]
As described above, the surface areas of the separated jets provided at the independent converging bell inlet 35 are shown in FIGS. 2, 4, 5 and 6 to further improve the air entrainment. . This is due to the fact that by dividing one large jet into several smaller jets, the surface area of the jet has increased and the diameter has decreased. The jet size decreases as a function of port diameter and jet spread in the surrounding fluid. The divergence angle, which is largely involved in the design of the gas port, also determines the surface area of the jet. Each jet formed using a separate gas port and multiple venturi tubes will entrain and diffuse air at the same velocity when supplied at the same fuel pressure. This diffusion / entrainment rate will increase the burner's ability to deliver a very thin fuel premix. Although not desirable, the composition of the premix from multiple venturi clusters can be adjusted when the mixture is below the flammability limit. By maintaining the premix composition within the flammability limits of the fuel being burned, it is possible to maximize the amount of air, which will eventually maximize the heat load on the flame. This additional heat load will lower the flame temperature and consequently reduce the formation of nitrogen oxides by heat.
[0040]
Another embodiment of a burner assembly embodying the principles and concepts of the present invention is schematically illustrated in FIG. In FIG. 11, the same components as those shown in FIGS. 1 to 5 are denoted by the same reference numerals. FIG. 11 shows a Venturi cluster 30 having only two Venturi tubes 32, but as mentioned above, the cluster 30 of FIG. It is possible to have more Venturi tubes. As shown in FIG. 11, each Venturi tube 32 comprises an elongated, essentially straight tube 64 that extends between the throat 36 and the outlet 38. As can be seen from the figure, the tubes 64 are arranged in parallel to each other. In particular, the tubes 64 are arranged so that fluids flow in parallel. However, in this regard, it should be noted that the configuration shown in FIG. 11 is not critical to the performance of the cluster 30. As can be appreciated by those skilled in the art, the downstream portion 64 of the venturi tube may not be straight, or may not be positioned parallel to each other.
[0041]
The burner tip 154 of the burner assembly of FIG. 11 is shown in more detail in FIG. 10 but preferably extends in the direction of the shaft 60 and provides a single mixed flow of fuel and air received from the collector 40. It is constructed and arranged so as to be guided outside and into the region 56 in a direction along the axis 60. For this purpose, the tip 154 has a plurality of apertures 66 at its downstream end 67 that allow the fuel and air mixed flow to flow along the axis 60 as shown in FIG. So that it is positioned.
[0042]
As shown in FIG. 11, each Venturi tube 32 is supplied with fuel gas via an inlet pipe or spud 68 and the air flow uses a movable control element 48 (handle 46 not shown in FIG. 11). Are controlled in the same manner as described above. Thus, in the embodiment of FIG. 11, the fuel gas is the induced fluid and the air is the induced fluid. The assembly 120 of FIG. 11 also includes an elongated central primary fuel tube 70 that extends along the central axis 60 of the assembly 120 as shown and projects through a hole 69 at the downstream end 67 of the tip 154. . A small venturi 72 is provided at the upstream end 74 of the tube 70 and primary fuel is supplied to the tube 70 through an inlet fuel spud or pipe 76. Thus, a primary mixture of air and fuel flows along the tube 70 toward the primary nozzle 78 located on the downstream end portion 80 of the tube 70 provided in the combustion zone 56. According to the present invention, the material supplied to the nozzle 78 is preferably an air / fuel premix, but raw fuel may be supplied to the nozzle 78 for stabilization purposes.
[0043]
As can be seen from FIG. 11, an opening 66 is disposed surrounding the tube 70. Thus, when a combustible mixture of fuel and air is discharged from the tip 154 through these openings 66, the mixture has a cylindrical shape extending toward the nozzle 78 so as to surround the tube 70. When the combustible mixture is ignited, a substantially cylindrical flame extending along the axis 60 is formed.
[0044]
A flame holder 82 for the purpose described later is attached to the tube 70 directly below the nozzle 78. Details of the preferred embodiment of the flame holder 82 and nozzle 78 are shown in FIGS. However, the burner tip 254 shown in FIG. 13 is different from the burner tip 154 of FIG. 11 in that the latter has a plurality of openings 66 in its end wall 156, whereas the burner tip 254 is on the downstream side. The end 256 is basically a wide open cylinder.
[0045]
Referring to FIG. 13, the flame holder 82 preferably has a conical shape with a vertex 84 remote from the nozzle 78. Preferably, the apex 84 is located about 8 inches above the upper end 256 of the tip 254. In one preferred form of the invention, the flame holder 82 has an outer diameter of about 10.2 cm (about 4 in) when the tube 70 is made of a pipe having a diameter of about 2.54 cm (1 in). The plate is formed of a specially shaped plate attached to the tube 70 by tack welding or mounting screws. The angle α formed by the shaft 60 and the conical skirt 83 of the flame holder 82 is preferably 45 degrees.
[0046]
In the most preferred form, the holder 82 has a plurality of holes 86 having a diameter of about ¼ inch distributed around the tube 70 in a pattern. These holes 86 are of sufficient size and number so that approximately 30% of the surface area of the holder 82 is ideally an open area. In this regard, however, it should be noted that according to the principles and concepts of the present invention, this open area should be in the range of about 10% or less to about 75% or more of the surface area of the holder 82. . To this end, according to the invention, the holder has various diameters depending on the diameter of the main opening of the burner to the furnace. Thus, the diameter of the holder 82 can vary from a quarter of the diameter of the main burner opening to the furnace to the same diameter as the main opening of the burner to the furnace. Further, the angle α is in a range from about 30 degrees or less to 80 degrees or more. In connection with the foregoing, the shape of the holder 82 is not a critical factor, but deflects the combustible mixture away from the tips 154, 254 to create a low pressure on the downstream side 300 of the flame holder 82, stabilizing ignition. Almost any shape can be used as long as it helps to draw the combustible mixture into the stagnant low speed range that is maintained.
[0047]
The nozzle 78 is preferably in the shape shown in FIG. 14 and is a cylindrical cup having a base 88 made of a piece made by drilling and machining a hexagonal bar and an open upper end 92. A portion 90 is provided. Base 88 includes holes 94 and cup portion 90 includes holes 96 that are sized and positioned to obtain the result that nozzle 78 provides the desired primary flame. . The cup portion 90 prevents the flame from being blown off from the open end 87 of the base 88 by the surrounding gas flow. In the absence of this flow, the cup portion 90 is not necessary.
[0048]
The configuration schematically shown in FIGS. 11, 13 and 14 provides very good nitrogen oxide reduction performance. As previously mentioned, the concept of providing a plurality of venturi tubes allows for the provision of a very thin premix of fuel that in itself allows for substantial nitrogen oxide reduction. Combining this concept of providing a plurality of Venturi tubes with the configuration of FIGS. 11, 13 and 14 further reduces nitrogen oxides by stabilizing the very thin premix in the low speed range.
[0049]
Referring to FIG. 11, a small portion of less than about 10%, preferably less than 2% of the total fuel is directed through the spud 76 and used to draw air from the air box 50. The fuel and air are premixed in a tube 70 that passes through the center of the burner. As previously mentioned, it may be desirable to supply raw fuel through the tube 70. The tube 70 passes through the primary premix gas tip 154 and ends with a shielded nozzle 78 provided at a distance above the primary or main premix tip 154. This distance can vary from less than about 3 inches to more than about 15 inches depending on the speed and pressure at which the premix leaves the chip 154 and the size of the burner. In this way, a small primary flame is reliably obtained at the high nozzle 78 provided above the upper end 156 of the main premix chip 154. A conical flame holder 82 made of a perforated plate is provided directly below the elevated nozzle 78 and the main premix mixture from the tip 154 is drawn into a stable primary flame formed adjacent to the nozzle 78. Provide a location. Thus, the cone 82 and primary nozzle 78 provide a mechanism to maintain a stable flame in a very fuel thin premix supplied from the tip 154. If a stable flame is established, the primary flame generated at the outlet end 92 of the nozzle 78 can be extinguished to further reduce nitrogen oxides.
[0050]
As mentioned above, positioning the primary flame at a position substantially upwardly away from the outlet of the burner tip 154 provides an opportunity to expand and slow down the main air / fuel mixture after exiting the main tip 154. provide. Thus, reducing the premix to a speed that is not greater than the flame speed is desirable for stabilization of a very fuel thin premix flame. A serious problem that occurs when using a very thin flammable mixture of fuel is that the flame speed varies directly with the fuel content. That is, the flame speed is very slow for very thin fuel mixtures. The temperature of the mixture also affects the flame speed, the higher the temperature, the faster the flame speed and vice versa. In other words, if the combustible mixture is very thin and contains too much excess air, the flow velocity coming out of the main burner tip will exceed the flame velocity and this state Then, the flame may be blown off from the burner chip.
[0051]
The flame speed is again reduced to the flow speed by slowing the ignition until the main fuel and air mixture emerges from the tip end, spreads into the furnace space, slows down and is heated gradually by hot ambient radiation. A situation is created that is faster and is easily maintained at a stable condition within the stability range provided by the nozzle 78 and holder 82 in a higher position. A refined blended fuel gas (nearly 5 ppm in the case of natural gas) is achieved by igniting and burning the main gas at a location that is substantially away from the main premix tip outlet in a stable state at low speeds. In the case of 25% hydrogen, 25% propane, 50% methane, for example, a nitrogen oxide reduction performance of less than 3 ppm, which could not be obtained conventionally, is obtained. In addition, a thin premix of fuel that has already been diluted expands and slows after exiting the main tip, thereby entraining furnace flue products that are being further diluted prior to ignition. This also greatly contributes to the reduction of nitrogen oxides.
[0052]
According to the configuration shown in FIG. 11, the central venturi 72 can be kept at a stable flammability limit even though the fuel is thin, and a plurality of surrounding venturi / common collectors 140 can be driven. It is possible to obtain a very thin mixture of fuels which is below the flammability limit and which can be fully oxidized depending on the furnace temperature.
[0053]
According to another aspect of the invention, the fuel / air mixture in the tube 70 is supplied by a cluster mechanism comprising a plurality of venturi tubes 32. This mechanism is shown schematically in FIG. In this case, the entire assembly includes two separate Venturi clusters, the outer cluster supplies the air / fuel premix to the burner tip 154 and the inner cluster supplies the air / fuel premix to the tube 70. To do. Another configuration in which the inner multiple venturi bundle is completely surrounded by the outer venturi bundle is shown schematically in FIG. As shown in FIG. 16, the outer venturi bundle includes a venturi tube 32 and a common collector 140, and the inner venturi bundle includes a venturi tube 72 and a common collector 340. In these cases where the inner multiple venturi bundle is contained within the outer multiple venturi bundle, the inner cluster operates within stable flammability limits and the outer cluster is a very thin fuel air / fuel premix. To provide the best conditions necessary for nitrogen oxide reduction. According to this kind of configuration, it is possible to easily make a very large burner having 6 or more venturi tubes in the inner bundle and 12 or more venturi tubes in the outer bundle.
[0054]
Referring to FIG. 12, it can be seen that the principles and concepts of the present invention are also applied to a radiant burner where the premix exits radially from the tip 354. In this regard, reference is made to pending commonly assigned US application Ser. No. 09 / 803,808 filed Mar. 12, 2001, the disclosure of which is incorporated herein by reference. Present as Thus, the burner assembly 320 shown schematically in FIG. 12 comprises an elongated burner tip 354 in one direction extending axially through the burner assembly, the burner tip being received from the collector 40. The single mixed flow is constructed and arranged to direct the combustion zone 56 substantially radially with respect to the axis 60. Accordingly, the burner tip 354 is constructed and arranged to form a round flat flame that surrounds the tip 354. Still referring to FIG. 12, this assembly 320 includes a central tube 170 and supplies secondary fuel to the combustion zone via nozzle 178.
[0055]
In a particularly preferred form of the invention, the burner tip 354 has the shape shown in FIGS. 8 and 9 where the tip 354 has a generally ring-shaped base portion 98 and a central axis 100. Further, the tip 354 has a plurality of longitudinally extending curved ribs 102 that are elongated, juxtaposed, and arranged at predetermined intervals along the circumference. The ribs 102 have a first end 104 attached to the base portion 98 and a second end 106 remote from the base portion 98. The second end 106 is located closer to the axis 60 than the first end 104. Ribs 102 and base portion 98 define a region 108 inside tip 354 that is configured to receive a flow of a mixture of fuel and air from collector 40. The ribs 102 form a plurality of curved slots 110 between each other. As apparent from FIGS. 8 and 9, these slots 110 flow from the region 108 outwardly from the region 108 in a direction including a radial direction and a vector extending along the axis 60. Arranged and positioned to enter the outer combustion zone 56.
[0056]
In the preferred form shown in FIGS. 8 and 9, the tip 354 also includes a crown-shaped portion 112 connected to each second end 106 of the tip 354. Preferably, the crown-shaped portion 112 includes a plurality of discontinuities 114 extending axially and radially, which discontinuities 114 allow the mixture exiting the region 108 through the slot 110 itself. It is provided in alignment with a particular slot 110 so that there is a significant axial flow through the mixture through the region 108. Ideally, the discontinuity 114 is such that the axial mixture flowing therethrough forms a previous mixing region 116 (see FIG. 12) outside the combustion zone 56 and the fuel flowing through the discontinuity 114. The air mixture surrounds this region 116 in the direction indicated by arrow 115 and rotates to be diluted by the flue gas before returning to the combustion zone for combustion. On the other hand, the direction of the premix flow flowing from the slot 110 is schematically indicated by an arrow 117. In a particularly preferred form of the invention, the crown-shaped portion 112 of the tip 354 includes an axially aligned central nozzle receiving opening 118 for gas.
[0057]
In one aspect of the present invention, a radiant wall burner is provided that has a combined venturi cluster and can achieve high heat generation with 100% premix. This was not possible before the present invention. Previously, the highest exotherm that can be achieved is approximately 1.79 × 10 6 by secondary air. ^Three It was about MJ / h (1.7MMBTU / h). However, secondary air generates higher nitrogen oxides than if all air is supplied as an air / fuel premix in the venturi section. This barrier was overcome by the new design disclosed herein with a composite venturi cluster consisting of a plurality of venturi tubes arranged in a single cluster for parallel fluid flow.
[0058]
The present invention reduces nitrogen oxides by gradual fuel supply, reduces noise in certain shapes, gradual gas jet with flue gas outside the burner, rapid nitrogen oxide reduction, secondary air Simplification of work without adjustment, short contour flame, high turndown ratio due to added premix tip speed, high stability, reduced CO generation, (additional mass flow and large Cooling of the premix chip (by heat transfer) and reduction of flashback problems due to the added chip speed.
[0059]
The present invention relates to multiple venturi tube configurations, and in particular to configurations that provide excess air for very thin fuel mixtures for premix applications. In particular, the present invention is useful in connection with any burner in which the radiant wall burner provides an axial flame. The present invention is also useful in connection with large process heaters with primary combustible mixtures formed with 100% or partial premix as a nitrogen oxide reduction mechanism. However, the configuration including a plurality of venturi tubes of the present invention has general applicability, and can be applied to general uses when a venturi tube is required. In particular, the multiple venturi tube configuration of the present invention operates to entrain more air than previously thought by increasing mass transfer and diffusion. In addition, the multi-venturi configuration of the present invention requires typical tank and container ventilation, air handling, solids transport and handling, and moving large quantities of material using short venturi tubes. It can be suitably applied to all cases.
[0060]
Previously, radiant wall burners would be about 1.58 × 10 unless another air source was used. ^Three It was impossible to reach a fever higher than MJ / h (1.5MMBtu / h). By using a plurality of parallel Venturi tubes and making them in the correct shape with careful attention to detail to ensure a reliable interaction between the Venturi tubes, approximately 10.6 × 10 ^Three Heat generation over MJ / h (10MMBtu / h) can be achieved.
[0061]
According to one aspect of the present invention, the present invention can be applied to a modular burner in which a venturi tube injector is added to enhance the capacity or reduce nitrogen oxides. In this concept, the burner is made up of multiple venturi tubes that can later be added to improve performance, or steam, flue gas or other inert gases can be added to reduce nitrogen oxides. May be. In another form, the invention is not limited to using flue gas as a diluent to reduce nitrogen oxides, but to use any other diluent that adds mass and cools the flame. Is possible. Such diluents range from inert gases such as nitrogen, steam and carbon dioxide to fuels with low BTU value fuels such as purified PSA gas and other fuels containing vapors or gas streams containing any proportion of combustible gas It has spread.
[0062]
In other forms, the present invention is applicable to a variety of process heater type burners that can be attached to the floor or roof rather than to the side walls of the furnace. They form a free upright round or flat flame. They function in a furnace where the walls do not have to be heated by the flame.
[0063]
In yet another form, instead of using fuel as a moving fluid in one or more injectors, steam or other compressed dilution gas having the characteristics described above is used as the moving fluid.
[0064]
A typical copy wall burner uses the power of a single gas spud to entrain atmospheric air. This new concept of using multiple parallel venturi tubes or injectors provides a new dimension to the combustion industry. The advantages of the present invention when applied to burner technology are as follows.
(1) Since the homogeneity of fuel gas and air is good, the flame is shortened.
(2) Large aperture ratio (3: 1 in prior art devices, but 10: 1).
(3) Noise around the burner is reduced.
(4) The tile is not exposed to the hot spot generated by the combustion jet, and the formation of holes is prevented.
(5) Since a 100% premix is used, secondary addition is unnecessary.
(6) The action of the burner becomes very stable.
(7) The burner can operate as calculated without causing flashback.
(8) Both prompt and thermal nitrogen oxides can be reduced by flue gas injection and mixing.
(9) The staged supply of fuel is facilitated by a single internal chip or multiple radial chips.
(10) Since the chip speed is high, flashback due to volatile fuel is reduced.
(11) Larger heat generation than previously thought possible.
[0065]
In accordance with the concepts and principles of the present invention, a burner with a novel combined venturi cluster that is the subject of the foregoing disclosure can be configured to ignite upward, downward, or horizontally. Furthermore, the burner consisting of a plurality of venturi pipes of the present invention is used to burn a combustible liquid such as fuel oil. Therefore, this burner can be applied to the combination ignition mechanism easily and with a few physical changes. It is also noteworthy that the burner of the present invention can be easily modified into various shapes. For example, the burner can be rectangular or any other desired shape rather than the circular flame described above.
[0066]
As is apparent from the foregoing description, the present invention provides a center for supplying a fuel / air premix to a central primary flame nozzle, or for supplying pure fuel to a central nozzle that supplies secondary fuel to a combustion zone. It is intended to use a Venturi cluster combined with a fuel tube.
[0067]
The principles and concepts of the present invention are applicable to providing a large burner mechanism with an inner multiple venturi cluster provided within an outer multiple venturi cluster.
[0068]
The present invention provides a number of novel features that are useful alone or in combination with a burner and / or burner assembly configured to burn fluid fuel. These fluid fuels may be fuel oil or the like, but are preferably gaseous fuels such as natural gas, propane, butane and hydrogen.
[Brief description of the drawings]
FIG. 1 is a front view of a burner assembly with a composite multi-venturi cluster embodying the concepts and principles of the present invention.
FIG. 2 is the same view as FIG. 1 except that the assembly is shown partly in cross section to show the internal parts.
FIG. 3 is a plan view of the burner assembly of FIG. 1;
4 is a cross-sectional view taken along line 4-4 of FIG.
FIG. 5 is a cross-sectional view taken along line 5-5 of FIG.
FIG. 6 is a partial cross-sectional front view showing a portion of another composite multi-venturi cluster that embodies the concepts and principles of the present invention.
7 is an enlarged detail view showing an enclosed portion 7 of the composite venturi cluster of FIG. 6. FIG.
FIG. 8 is a perspective view of one embodiment of a burner tip embodying the concepts and principles of the present invention used in combination with a composite venturi cluster of the present invention to form a burner assembly.
FIG. 9 is a plan view of the burner chip of FIG. 8;
FIG. 10 is a perspective view of another embodiment of a burner tip embodying the concepts and principles of the present invention used in combination with a composite venturi cluster of the present invention to form a burner assembly. .
FIG. 11 is a schematic diagram of yet another embodiment of a burner assembly embodying the concepts and principles of the present invention.
FIG. 12 is a schematic diagram of yet another embodiment of a burner assembly embodying the concepts and principles of the present invention.
FIG. 13 is a partial cross-sectional front view showing the downstream portion of yet another embodiment of a burner assembly embodying the concepts and principles of the present invention.
FIG. 14 is an enlarged cross-sectional view showing details of the burner assembly of FIG. 13;
FIG. 15 is a plan view of the burner assembly of FIG. 13;
FIG. 16 is a schematic view of the same burner assembly as that of FIGS. 11 and 17, except that the central venturi bundle is surrounded by the outer venturi bundle.
FIG. 17 is a schematic view of yet another embodiment of the burner assembly of FIG.
[Explanation of symbols]
20 ... Burner assembly
22 ... Cylindrical shell
24 ... Secondary fuel nozzle
26 ... Fuel manifold
28 ... Composite type venturi structure
30 ... Venturi cluster
32 ... Venturi tube
34 ... Entrance
36 ... Throat
38 ... Exit

Claims (85)

A composite venturi structure comprising a venturi cluster, an elongated collector, and an elongated tubular segment:
The venturi cluster includes at least two venturi tubes, each of the venturi tubes comprising an elongate venturi main body portion forming a conduit, a venturi tube inlet, and a venturi tube outlet; Each tube is arranged and configured to cause a flow of induced material by passing the induced fluid, whereby each mixture of induced material and induced fluid is discharged from the venturi tube outlet;
The elongated collector is adapted to receive each of the mixture of induced material and induced fluid discharged from the venturi tube outlet and to provide a single mixture of the induced fluid and the induced material. The collector is arranged and configured to collect and intermix, and the collector has an outer peripheral wall forming an internal mixing chamber, an inlet end, an outlet end, and a longitudinal length extending between the ends. A central axis extending in a direction, wherein the elongated venturi main body portion is arranged substantially parallel to the central axis;
Each of the elongate tubular segments is for each of the venturi tubes, and the tubular segments are arranged and configured to interconnect and communicate the inlet end of the collector and the venturi tube outlet. Each of the tubular segments includes an inlet connected to the outlet of a corresponding venturi tube and an outlet connected to the inlet end of the collector, each tubular segment further with respect to the central axis. Oriented to extend outwardly away from the inlet end of the collector at a predetermined angle so that the inlet of the tubular segment and the inlet of the corresponding venturi tube are radially from the central axis. Arranged at spaced apart positions, the spaced distance from the central axis of the outlet of the tubular segment And it has a longer distance than the distance to the point being connected to the collector; composite venturi structure. The composite venturi structure of claim 1, wherein all of the venturi inlets are substantially coplanar. The composite venturi structure according to claim 1, wherein the venturi cluster includes at least three of the venturi tubes. 4. The composite venturi structure according to claim 3, wherein the venturi cluster comprises at least six of the venturi tubes. The composite venturi structure according to claim 1, 3 or 4, wherein an inlet end of each of the venturi pipes has a bell shape. The composite venturi structure according to claim 1, wherein the induced substance is a fluid. The composite venturi structure according to claim 1, wherein the induced substance is a fluid solid. The composite venturi structure according to claim 1, 3 or 4, wherein the venturi tubes have the same physical capacity. The composite venturi structure according to claim 1, 3 or 4, wherein at least one of the venturi tubes has a physical capacity different from that of the other venturi tubes. The composite venturi structure of claim 1, comprising a central tube passing through the collector along the central axis. The composite venturi structure of claim 10, wherein the composite venturi structure includes a single venturi tube connected to an upstream end of the central tube. The composite venturi structure of claim 10, wherein the composite venturi structure includes a plurality of venturi tubes connected to an upstream end of the central tube. Combined ben including first and second venturi cluster devices A Turley structure, wherein the first and second venturi cluster devices comprise a venturi cluster and a collector:
The venturi cluster includes at least two venturi tubes, and each of the venturi tubes has an inlet, a slot, and an outlet, and is arranged and configured to cause a flow of the induced substance by passing the induction fluid. Whereby each mixture of induced substance and induced fluid is discharged from the outlet;
The collector has an inlet end connected to and in fluid communication with the outlet of the venturi tube, whereby a mixture of induced fluid and induced material discharged from the outlet Each collected and mixed together to form a single mixed flow of the inducing fluid and the induced material;
The venturi tubes of the first venturi cluster device are spaced apart, the collector is annular to provide a central space, and the second venturi cluster device is arranged in the central space; a composite venturi Structure. A burner assembly comprising a venturi cluster, an elongated collector, an elongated tubular segment and a burner tip:
The venturi cluster includes at least two venturi tubes, each of the venturi tubes comprising an elongate venturi main body portion forming a conduit, a venturi tube inlet, and a venturi tube outlet; Each of the tubes is arranged and configured to cause a flow of the induced fluid by passing the induced fluid, whereby each mixture of the induced fluid and the induced fluid is discharged from the venturi tube outlet;
The collector receives the mixture of induced fluid and induced fluid discharged from the venturi tube outlet, respectively, and provides the mixture to provide a single mixture of the induced fluid and the induced fluid. Arranged and configured for collection and intermixing, the collector comprising an outer peripheral wall forming an internal mixing chamber, an inlet end, an outlet end, and a longitudinal direction extending between the ends An elongated central axis, and the elongated venturi main body portion is arranged substantially parallel to the central axis;
Each of the elongate tubular segments is for each of the venturi tubes, and the tubular segments are arranged and configured to interconnect and communicate the inlet end of the collector and the venturi tube outlet. Each of the tubular segments includes an inlet connected to the outlet of a corresponding venturi tube and an outlet connected to the inlet end of the collector, each tubular segment further with respect to the central axis. Oriented to extend outwardly away from the inlet end of the collector at a predetermined angle so that the inlet of the tubular segment and the inlet of the corresponding venturi tube are radially from the central axis. Arranged at spaced apart positions, the spaced distance from the central axis of the outlet of the tubular segment It has a longer distance distance to a point which is connected to the collector;
The burner tip is attached to and in fluid communication with the outlet end of the collector such that the burner tip receives the single mixed flow of fluid from the collector and directs it toward the combustion zone. In place; burner assembly. The burner assembly of claim 14, wherein all of the venturi inlets are arranged in substantially the same plane. A very thin mixture of the air and the gaseous fuel to induce an air flow by receiving gaseous fuel at the venturi inlet and to allow the gaseous fuel to pass through the conduit; 15. The burner assembly according to claim 14, wherein each of the venturi tubes is arranged and configured to further discharge the very fuel thin mixture from the venturi tube outlet to produce 15. A burner assembly according to claim 14, wherein at least one of the venturi tubes is arranged and configured to operate with gaseous fuel as a guiding fluid. 18. A burner according to claim 17, wherein at least one of said venturi tubes is arranged and configured to be actuated by air as an induced fluid, whereby said single mixed flow is composed of fluid fuel and air. assembly. The at least one of the venturi tubes is arranged and configured to operate with recirculating flue gas as an induced fluid, whereby the single mixed flow is composed of fluid fuel and recirculating flue gas; The burner assembly according to claim 17. The other one of the Venturi tubes is arranged and configured to operate with gaseous fuel as the guiding fluid and recirculating flue gas as the induced fluid, so that the single mixed stream is fluid fuel and air 19. A burner assembly according to claim 18, comprising a recirculating flue gas. At least one of the venturi tubes is arranged and configured to operate with a combustion inert diluent as an induced fluid, whereby the single mixed stream is composed of a fluid fuel and the combustion inert diluent. The burner assembly according to claim 17. The burner assembly of claim 21, wherein the combustion inert diluent is steam. The burner assembly of claim 21, wherein the combustion inert diluent is nitrogen. 15. The venturi is arranged and configured to operate with gaseous fuel as a guiding fluid and with air as a guided fluid, respectively, whereby the single mixed flow is composed of gaseous fuel and air. Burner assembly as described in 15. A burner assembly according to claim 14, wherein the induction fluid is a gaseous fuel. 15. A burner assembly according to claim 14, wherein the induction fluid is fuel oil. 27. A burner assembly according to claim 14, 15 or 26, wherein the induced fluid comprises air. The combustion inert diluent is CO ₂ The burner assembly according to claim 21, wherein A burner assembly comprising a Venturi cluster, a collector and a burner tip:
The venturi cluster includes at least two venturi tubes, each of the venturi tubes including an elongated venturi main body portion forming a burner conduit, a venturi tube inlet, and a venturi tube outlet ( 1) In order to induce air flow when gaseous fuel is introduced into the venturi inlet and to pass the gaseous fuel through the conduit, (2) a very thin mixture of the air and the gaseous fuel is used. And (3) each venturi tube is arranged and configured to further discharge the very thin fuel mixture from the venturi tube outlet;
The collector has an inlet end connected and arranged in fluid communication with the outlet of the venturi tube, so that each very thin fuel and fuel mixture discharged from the venturi outlet is each Collected and intermixed to provide a very thin single mixed flow of air and fuel;
The burner tip is connected and arranged in fluid communication with the outlet end of the collector and receives the single thin mixed stream of air and fuel from the collector and introduces it into the combustion zone;
Burner assembly. 30. The burner assembly according to claim 29, including a second fuel nozzle for supplying auxiliary fuel to the combustion zone. The Venturi tube allows the very thin mixture of fuel to burn 31. A burner assembly according to claim 30, wherein the burner assembly is arranged and configured to include all of the air necessary to promote combustion of fuel supplied to the zone. 30. A burner assembly according to claim 29, wherein the venturi cluster comprises at least three of the venturi tubes. The burner assembly according to claim 32, wherein the venturi cluster comprises at least six of the venturi tubes. 34. A burner assembly according to claim 29, 32 or 33, wherein the inlet end of each of the venturi tubes is bell-shaped. 35. The burner assembly of claim 34, wherein each of the venturi tubes includes straight portions that are arranged substantially parallel to each other. 34. A burner assembly according to claim 29, 32 or 33, wherein the venturi tubes have the same physical capacity. 34. A burner assembly according to claim 29, 32 or 33, wherein at least one of the venturi tubes has a different physical capacity than the other venturi tubes. 34. A burner assembly according to claim 29, 32 or 33, wherein the collector is elongated and the collector includes a central axis extending between the ends. 39. A burner assembly according to claim 38, comprising a central fuel tube passing through the collector along the central axis. The collector inlet end includes an open segment for each venturi tube, and the venturi tube outlets are each in fluid communication with a corresponding segment, the open segment in a row around the central fuel tube. 40. The burner assembly according to claim 39, arranged in a row. 40. A burner assembly according to claim 39, wherein the upstream end of the central fuel tube is configured to be connected to a fuel source. 40. The burner assembly according to claim 39, wherein the upstream end of the central fuel tube is configured to be connected to an air / fuel premix source. 43. The burner assembly according to claim 42, wherein the burner assembly comprises a venturi tube connected to an upstream end of the central fuel tube. 43. The burner assembly according to claim 42, wherein the burner assembly comprises a plurality of venturi clusters connected to an upstream end of the central fuel tube. 41. A method according to any one of claims 40, wherein the central fuel tube has a downstream end portion extending through the burner tip and protruding through an opening located in the center of the downstream end of the burner tip. Burner assembly. 46. A burner assembly according to claim 45, comprising a fuel nozzle at a downstream end portion of the central fuel tube. The tip is elongate and is configured and arranged to direct the single fuel mixture from the tip with very thin fuel toward the combustion zone in a substantially radial direction relative to the longitudinal axis of the tip; 46. A burner assembly according to claim 29 or 45. 48. A burner assembly according to claim 47, wherein the tip is constructed and arranged to form a round flat flame surrounding the tip. The tip is elongate and is configured and arranged to direct the single fuel mixture from the tip, which is very thin, to the combustion zone substantially axially with respect to the longitudinal axis of the tip; 46. A burner assembly according to claim 29 or 45. 50. A burner assembly according to claim 49, wherein the tip is configured and arranged to form a cylindrical flame extending along the axis. 49. The burner assembly according to claim 48, wherein the fuel nozzle is configured and arranged to provide secondary fuel to the combustion zone. The Venturi tube is arranged so that the very thin mixture of fuel contains all the air necessary to promote combustion of the fuel supplied to the combustion zone. 52. A burner assembly according to claim 29 or 51, wherein the burner assembly is constructed. 51. The burner assembly according to claim 50, wherein the fuel nozzle is constructed and arranged to provide a continuous flame at a location in a combustion zone axially spaced from the downstream end of the tip. 54. The position of claim 53, wherein the position is sufficiently away from the downstream end of the combustion zone so that the velocity of a single mixed flow from the tip toward the vicinity of the fuel nozzle does not become greater than the flame maintenance rate. Burner assembly. A burner assembly comprising a burner tube structure, a burner tip, an elongated central fuel tube and a fuel nozzle:
The burner tube structure includes an elongated burner conduit having an inlet end and an outlet end spaced apart from each other such that the conduit directs a gaseous mixture containing fluid fuel and oxygen from the inlet to the outlet. Configured and arranged;
The burner tip is at the outlet end of the conduit, the burner tip having a central axis and a downstream end spaced from the outlet end of the conduit, the tip receiving the mixture from the conduit and removing it. Arranged and configured to be directed to the combustion zone in a direction along the central axis through one or more holes in the downstream end;
The elongate central fuel tube extends through the tip along the central axis, the fuel tube protrudes axially from the tip through the downstream end, and the fuel tube is downstream of the burner tip. Having a downstream end portion located in the combustion zone in a spaced relationship with respect to the end, the one or more holes being disposed around the fuel tube and thereby through the one or more holes toward the combustion zone The mixture has a generally cylindrical shape surrounding the fuel tube and exits from the downstream end of the tip along the axis toward the downstream end portion of the fuel tube;
The fuel nozzle is above the downstream end portion of the fuel tube, the fuel nozzle is provided at a position in the combustion zone sufficiently separated from the downstream end of the burner tip, and the mixture is disposed at the downstream end of the tip. Expands after leaving, allowing it to reach the vicinity of the fuel nozzle by decelerating to a speed lower than the flame speed;
But the burner assembly. The mixture is a mixture of gaseous fuel and air, and the burner tube structure comprises a venturi tube that induces an air flow utilizing the flow of the gaseous fuel, thereby forming the mixture. 56. A burner assembly according to item 55. The mixture is a mixture of gaseous fuel and air, and the burner tube structure is composed of a plurality of venturi tubes arranged to form a parallel flow, and each of the venturi tubes carries the flow of the gaseous fuel. 56. The burner assembly according to claim 55, wherein the burner assembly is configured and arranged to utilize an air flow to thereby produce the mixture as a very thin fuel / air mixture. 56. A burner assembly according to claim 55, wherein the burner tip comprises an end wall at the downstream end thereof, the end wall comprising a plurality of the holes and a central opening for the fuel tube. A generally domed burner tip having a base portion and a plurality of ribs:
Its base part is substantially ring-shaped and has a central axis;
The plurality of ribs are spaced elongate laterally as well as circumferentially spaced and curved longitudinally, extend in a direction along the central axis, and have a first end mounted on the base portion and the A second end remote from the base portion, wherein the second end is located closer to the central axis than the first end, and the base portion and the rib are air and fluid fuel inside the tip. Forming a region configured to receive a flow of the mixture, wherein the ribs form a plurality of curved slots therebetween, and the mixture is radially directed from the region to a combustion region outside the burner tip. And in a direction that includes a vector extending along the axis;
However, the burner tip is almost domed. 60. A burner tip according to claim 59, comprising a crown-shaped portion connected to the second end of the rib. The crown-shaped portion includes a plurality of discontinuous portions extending in an axial direction and a radial direction, and the discontinuous portion is an air / fuel mixture in which an air / fluid fuel mixture flowing through the discontinuous portion flows through a slot. 61. The burner tip of claim 60, wherein the burner tip is aligned with each slot to have a more significant axial flow relative to. 62. The burner tip of claim 61, wherein the discontinuous portion is arranged to allow air / fluid fuel mixture to pass therethrough and forms a pre-stage mixing region outside the combustion zone. 61. A burner tip according to claim 60, wherein the crown-shaped portion has an axially aligned gas nozzle receiving opening therein. 60. A burner assembly comprising a composite venturi structure and a burner tip according to claim 59 provided at a downstream end of the composite venturi structure, wherein the composite venturi structure is a venturi cluster. With collectors:
The venturi cluster comprises at least two venturi tubes, each venturi tube having an inlet, a throat, and an outlet, each arranged to induce a flow of induced fluid by passing the guiding fluid through it. Configured so that each mixture of induced and induced fluid is discharged from the outlet;
The collector has an upstream end connected to and in fluid communication with the outlet of the venturi tube so that each of the mixture of induced and induced fluid discharged from the outlet is collected and mutually Mixed to form a single mixed flow of fluid, the burner tip being attached and fluidly connected to the outlet end of the collector and receiving the single mixed flow of fluid from the collector And arranged to distribute it to the combustion zone;
But the burner assembly. The composite venturi cluster according to claim 64, wherein the single mixed flow of fluid is composed of fuel and air. 66. The composite venturi cluster of claim 65, wherein the single mixed stream of fluid is comprised of a very thin fuel fluid fuel and air mixture. In a Venturi device capacity increase method for introducing a flow of induced material into a guide fluid when a flow of the induction fluid passes through the device, the Venturi device capacity increase method includes:
Separating the first fluid into at least two diverted portions;
Each of the diverted portions of the first fluid is individually guided through each venturi tube and the flow of the induced material is introduced into each of the diverted portions, whereby the diverted mixture of the induced material and the induced fluid. Forming each one;
Each diverted mixture is mixed to form a mixture with an induced material having a concentration higher than that of the induced material that would be obtained by passing the entire amount of the induced fluid through a single Venturi tube. Stages;
Venturi device capacity increasing method comprising: 68. A method according to claim 67, wherein the induction fluid is diverted into at least three of the diversion portions. 68. A method according to claim 67, wherein said guiding fluid is diverted into at least six said diverted portions. 68. The method of increasing venturi device capacity of claim 67, wherein the inductive fluid is a gaseous fuel. The method for increasing the capacity of a venturi device according to claim 70, wherein the induced substance is air. When the flow of the induction fluid passes through the device, the induced substance is introduced into the induction fluid. In a venturi device length reduction method configured to be introduced, a venturi device length reduction method includes:
Separating the induction fluid into at least two diverted portions;
Each of the diverted portions of the induced fluid is individually guided through each venturi tube and introduced into the diverted portion by separately guiding the flow of the induced material, thereby each of the diverted mixtures of the induced material and the induced fluid. Forming a step;
Mixing each diverted mixture with an induced substance having a concentration higher than that of the induced substance that would be obtained by passing the entire amount of said guiding fluid through a single venturi tube of the same length. Forming a mixture;
Venturi device length shortening method including. Venturi device operation method:
Providing at least two venturi tubes, each venturi tube having an inlet, a throat, and an outlet, each of which induces a flow of the induced material as the induced fluid passes through it, Forming a mixture of the substance and the induction fluid, respectively, and operating to discharge the mixture from its outlet;
Passing a first induction fluid through the first tube of the venturi tube, thereby inducing a flow of the first induced material to form a first mixture of the first induced fluid and the first induced material; And discharging the first mixture from the outlet of the first venturi tube;
Passing a second induction fluid through the second tube of the Venturi tube, thereby inducing a flow of the second induced material, and a second mixture comprising the second induced fluid and the second induced material Forming and discharging the second mixture from an outlet of the second venturi tube;
Collecting and mixing the first and second mixtures together to form a single mixed flow of the fluid and material;
Venturi operation method including. 74. A venturi operating method according to claim 62, 72 or 73, wherein the substance is a fluid. 74. A venturi operating method according to claim 62, 72 or 73, wherein the substance is a flowable solid. In a burner operating method comprising a venturi device for supplying a combustible mixture to a burner nozzle, the burner operating method includes:
Providing at least two venturi tubes, each venturi tube having an inlet, a throat and an outlet, each of which induces a flow of the induced fluid as it passes through it, Forming a mixture of each of the gas and the inductive fluid and operating to discharge the mixture from its outlet;
Passing a first induced fluid through the first tube of the venturi tube, thereby guiding a flow of the first induced fluid to form a first mixture of the first induced fluid and the first induced fluid; And discharging the first mixture from the outlet of the first venturi tube;
Passing a second induced fluid through the second tube of the venturi tube, thereby guiding a flow of the second induced fluid to form a second mixture of the second induced fluid and the second induced fluid. And discharging the second mixture from the outlet of the second venturi tube;
Collecting and mixing the first and second mixtures together to form a single combustible mixed stream of the fluids;
Including burner operation method. 77. The burner operating method according to claim 76, wherein each of the first and second induction fluids is a gaseous fuel. 78. A burner operating method according to claim 77, wherein the first and second induced fluids are each air. 78. A burner operating method according to claim 77, wherein the first induced fluid is air and the second induced fluid is recirculated flue gas. 77. A burner according to claim 76, wherein one of the induced fluids is a diluent. Method of operation. The burner operating method according to claim 80, wherein the diluent is steam. The burner operating method according to claim 80, wherein the diluent is nitrogen. The fluid single combustible mixture stream is thin of fuel and is fed to the combustion zone at a rate exceeding the flame rate of the mixture;
Allowing the mixture to expand and thereby decelerate to a speed not greater than the flame speed; igniting the mixture for the first time after obtaining the speed not greater than the flame speed; Contains;
The burner operating method according to claim 78. Burner operation method is:
Supplying a combustible mixture of fuel and air from the nozzle to the combustion zone with a composition such that the flame speed of the mixture is slower than the speed of the mixture as it exits the nozzle;
Allowing the mixture to expand and thereby decelerate to a speed not greater than the flame speed;
Igniting the mixture for the first time after obtaining the speed not greater than the flame speed;
Including burner operation method. 85. A burner operating method according to claim 84, wherein the mixture is very thin in fuel.

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