MX2007005133A - Counterflow fuel injection nozzle in a burner-boiler system - Google Patents

Abstract

A counterflow fuel injection nozzle for injecting fuel is disclosed. The nozzle includes a nozzle wall having an interior surface that defines a nozzle interior, the interior for receiving a fuel therein. The nozzle further has a fuel passageway formed in the nozzle wall for distributing the fuel from the interior to a location exterior of the nozzle, the fuel distributed to the exterior location in a fuel flow injection direction. An airstream is provided in a prevailing air flow direction in the location exterior of the nozzle. At least one vector component of the fuel flow injection direction opposes at least one vector component of the prevailing air flow direction. In this manner, by distributing fuel into an air flow at a counterflow angle, improved control of mixing of the fuel in the air is achieved. The counterflow nozzle may be included as part of a new burner or as a retrofit to existing burners in order to incorporate counterflow mixing. Advantageously, burner turndown rat ios and stability are enhanced through the use of the counterflow fuel injection nozzles with burners that use FGR (i.e., have lower O2 in combustion air supplied to the burner).

Description

FUEL INJECTION NOZZLE OF COUNTERFLOW IN A BURNER-BOILER SYSTEM CROSS REFERENCE WITH RELATED REQUESTS This application is a Continuation in Part of the US Patent Application Series No. 10 / 857,399 filed May 28, 2004, pending, which also claims the benefit of the filing date of the North American Application Series No. 60 / 474,470 filed on May 31, 2003. Field of the Invention The field of the present invention relates generally to fuel injection nozzles, and more particularly, to a counterflow fuel injection nozzle. BACKGROUND OF THE INVENTION Burners are used as boilers, heaters and other applications for the conversion of fuel to heat. Subsequently the heat is transferred to create hot water, steam and / or hot air or to create power, depending on the application. In a burner-boiler system (for example, commercial and industrial water pipe and fire tube boilers) fuel is usually injected through the nozzles to create a flame. The fuel is combined with an air flow around or adjacent to the nozzle.

Finally, the fuel is ignited to create a flame, the goal being to maximize the conversion of the fuel that is burned during this combustion process, in order to achieve a complete combustion. The way in which the fuel is injected (for example, its direction speed and interaction with other fluid streams) in the air stream, affects the profile and shape of the flame and therefore determines to a large extent the completeness of the heat release fuel in the furnace. The injection method affects the general geometric and physical characteristics of the nozzle itself. For example, fuel is usually injected through passages formed in the nozzle, and more particularly, the body of the nozzle. These physical characteristics include the width or diameter, spacing or angle or degree of inclination of the particular passages or channels. It is a continuous design goal to control the mixing (eg, quality, uniformity, range, etc.) of the fuel and air through the burner, so that the air and fuel mix uniformly. Variations in the width, spacing and degree of inclination of the nozzle passages used to distribute the fuel from the nozzle produce mixed results, flame profiles, flame locations and varied general combustion performance factors. It has been found that the angled injection passages that inject the fuel in a counterflow manner contribute positively to the aforementioned factors. By the term "backflow" it is meant that the fuel is injected into an air flow so that at least one fuel vector component flows in opposite manner to at least one vector component of the air flow. Accordingly, it would be desirable, in a burner using a gas fuel (e.g., natural gas) that has the ability to improve the mixing control of the fuel with air, by introducing the fuel into the air in a counterflow mode. BRIEF DESCRIPTION OF THE INVENTION In the present invention there is disclosed a counterflow fuel injection nozzle for fuel injection, wherein the nozzle comprises: a nozzle wall having an interior surface defining the interior of a nozzle. The interior to receive a fuel therein, the nozzle also having a fuel passage formed in the wall of the nozzle to distribute the fuel from the interior to an external part of the nozzle, the fuel being distributed to the exterior location in a direction of fuel flow injection. When an air stream is provided in a prevailing airflow direction at the outer location of the nozzle, at least one fuel vector component flows in the opposite injection direction at least one vector component of the prevailing air flow direction. Other objects, aspects and advantages of the present invention can be appreciated from the full reading of the detailed description that follows, together with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS The embodiments of the present invention are described with reference to the accompanying drawings and are for purposes of illustration only. The present invention is not limited in its application to the details of construction or to the adjustment of the components illustrated in the drawings. The present invention has the capacity of other embodiments or of being practiced or carried out in other various forms. Similar reference numbers are used to indicate similar components. In the drawings: Figure 1 is a partially cutaway perspective view of a burner incorporating a counterflow fuel injection nozzle embodiment of the present invention.; Figure 1a is a front view of a burner incorporating a counterflow fuel injection nozzle embodiment of the present invention; Figure 2a is a side sectional view taken along the line 2a-2a of Figure 1a; Figure 2b is a diagram schematically illustrating the concept of counterflow with respect to a representation of the fuel injection nozzles of the counterflow fuel injection nozzles of the present invention; Figure 2c, is a representation of various parameters of holes and distances associated with the counterflow fuel injection nozzle illustrating the parameters affecting the interaction of the fuel jets from adjacent nozzles; Figure 2d is a representation of various fuel penetration depths and general fuel distribution patterns associated with the present invention; Figure 3 is an expanded sectional view taken along line 3-3 of Figure 2a; Figure 4 is a perspective view of an embodiment of the counterflow fuel injection nozzle according to an aspect of the present invention; Figure 5 is a sectional view of the bottom taken along line 5-5 of Figure 3; Figure 6 is a perspective view of another embodiment of the counterflow fuel injection nozzle according to an aspect of the present invention; Figure 7 is a side sectional view of the counterflow fuel injection nozzle of Figure 6; Figure 8 is a sectional view of the bottom taken along line 8-8 of Figure 7 and illustrating exemplary counterflow injection angles; Figure 9 is a perspective view of another embodiment of the counterflow fuel injection nozzle according to an aspect of the present invention; Figure 10 is a side sectional view of the counterflow fuel injection nozzle of Figure 9; Figure 11 is a view of the front section taken along line 11-11 of Figure 10 and illustrating the exemplary angular displacement of the fuel injection holes; Figure 12 is a perspective view of another embodiment of the counterflow fuel injection nozzle according to an aspect of the present invention; Figure 13 is a view of the side section of the counterflow fuel injection nozzle of Figure 12; Figure 14 is a partial view of the side section of another embodiment of the counterflow fuel injection nozzle according to an aspect of the present invention; and Figure 15 is a perspective view of the counterflow fuel injection nozzle of Figure 14. Detailed Description of the Invention In the figures, like numbers are used to designate equal parts through the drawings and various pieces of equipment, such as valves, attachments, pumps and the like are omitted to simplify the description of the present invention. However, those skilled in the art will appreciate that such conventional equipment can be used as needed. In addition, although the present invention can be applied to various burner-fuel equipment, it will be described for purposes of illustration in connection with a steam or hot water burner. Figure 1 is a partially cutaway perspective view of a burner 1 incorporating a counterflow fuel injection nozzle 2 embodiment of the present invention. The burner 1 can receive a gaseous fuel (e.g., propane, natural gas, etc.) from a fuel source (not shown) through a fuel line or pipe (not shown) and supplied within the burner through of the lance 14. The total combustion air flow is indicated by arrow 3, with the primary air 4, secondary air 5 and tertiary air 6 flowing through other paths (such as directed at the inlet of the burner, for example, around a diffuser 7 and between the injection nozzles) to promote complete combustion. Air flows can have, in addition to air, gas products from the flue pipe (FGR). In general, levels 02 are lower in gas products from the flue pipe than in the air. Therefore, more air may be necessary in primary, secondary and tertiary air flows to achieve the necessary oxygen levels required for complete combustion. The oxygen levels may preferably be within the range of 11 to 21%, more preferably within the range of 15 to 21%, and most preferably within the range of 16 to 19%. Figure 1a is a front view of a burner incorporating a counterflow fuel injection nozzle embodiment of the present invention, and Figure 2a is a side elevation view taken along line 2a-2a of Figure 1a. With reference to Figures 1a and 2a, fuel is introduced into the burner 10 at a number of locations through the manifold 11. More specifically, fuel is introduced through a plurality of fuel lines placed in the form of radial or spears 14. In addition, the central injection pipe 13 is used to distribute fuel through the nozzles 15 to create a flame in the center of the burner. The burner 10 further includes a diffuser (also called a "swirl maker"), generally referred to as number 18, having blades 20. The tertiary air is introduced into the burner 10, also indicated with the number 6, and the diffuser 18 in part of a rotational movement to the air to thereby increase the mixing of air and fuel. The radially placed lances 14 end with the injection nozzles 16, also referred to in the present invention simply as "injectors" or nozzles. The distance 19 between the head 17 of the nozzle 16 and the beginning of the flat area of the diffuser 21, is an important factor for the successful application of the nozzle 16 as it will affect the fuel and air mixing capacities. The gap between the nozzle 16 and the outer ring 25, as indicated by the arrow 27, is also important for the mixing capabilities. The primary, secondary and tertiary air is introduced into the burner 10 as shown. In the embodiment shown, the "prevailing air flow direction" corresponds to an air flow direction in which the air travels from a generally upstream location of the fuel injectors to a location generally in the downstream of the air inlets. fuel injectors. The flow of air can be influenced by the structures or "body that simulates resources that it lacks" inside the burner itself (for example, diffuser, manifolds, fuel lines, etc). As will be described in more detail below, and as shown in Figure 1, at least a part of whether air flow is directed or distributed to pass through the diffuser and generally along or through the nozzles 16. Figure 2b is a diagram illustrating in schematic form the concept of counterflow with respect to a representation of the counterflow fuel extension nozzle of the present invention. As shown, the fuel flows into the nozzle 510 in an initial fuel flow direction 518 and flows into the interior 514 of the nozzle. The fuel is distributed from the interior of the nozzle 514 along an injection of fuel flow 520 (Fuel). The fuel is usually injected at a preferred pressure of up to 20 psig. "The fuel flow injection angle" is the angle at which the fuel is injected out of the counterflow fuel injection nozzle, and more specifically, the interior of the nozzle, through openings, holes or holes 516a-b to the outer location of the nozzle. The fuel flow injection direction is determined by the fuel flow injection angle T in which fuel is distributed from the interior of the nozzle. The trajectory is determined by the angle, as well as the fuel and the velocity of the air. As shown, the angle is shown from a plane that is normal or perpendicular to the surface of the nozzle. The fuel flowing along the fuel flow injection direction 520 includes a vector component 522 ^ ">; ^ and a counterflow vector component 524 ((, >).) Through the term "perpendicular" it is meant that the vector component is perpendicular to the prevailing air flow direction, and by the term "counterflow", it is it understands that the vector component is opposite to the prevailing air flow direction.To promote the mixing of fuel and air, the fuel is injected along the fuel injection direction 520 in the air flowing in the direction of prevailing air flow 526 (air) Mixing normally occurs at an exterior location of the nozzle.It should be noted that the fuel flow injection direction vector is shown in a schematic mode, to illustrate the flow injection angle of fuel more clearly, although the trajectory of the fuel flow takes a more complex trajectory (for example, its curves or eddies) due to fuel injection in the prevailing air flow increases as the fuel travels the distance from the nozzle. This more complex trajectory is indicated by the arrow 525. The fuel flows in the direction of fuel flow injection so that it is generally angled with respect to the prevailing airflow direction, resulting in a counterflow angle? which is measured with respect to the direction of prevailing air flow. The "counterflow angle" exists when at least one vector component (e.g., a fuel vector and counterflow component) of the fuel flow direction is opposed to at least one vector component of the flow direction of the fuel. prevailing air (ie, a counterflow air vector component). As shown schematically, the counterflow fuel vector component 524 opposes or is in opposite (and therefore counterflow to) at least one backflow air vector component of the flow direction of prevailing air 526. An important purpose for distributing the fuel in an air flow to create a counterflow angle is to achieve, or substantially achieve, complete mixing of the fuel in the air. Preferably, the spectrum of the fuel flow injection angles T, ranges from about 15 ° to about 90 ° (for example, where 90 ° means a complete counterflow). In a preferred embodiment, the counterflow angle is approximately 30 °. Figure 3 is an expanded sectional view taken along line 3-3 of Figure 2a, in particular, illustrating a sectioned view of the nozzle 16 according to an aspect of the present invention, in greater detail. Figure 4 is a perspective listing in a counterflow fuel injection nozzle embodiment according to an aspect of the present invention. The injection nozzle 16 includes a nozzle body 28. And Figure 5 is a sectional view from the bottom taken along line 5-5 of Figure 3. Referring now to Figures 3 to 5 , the nozzle body 28 has a nozzle wall 30, and the nozzle wall 30 defines the interior of a nozzle 32. As shown, the nozzle 16 generally has a "T" shape. It is the interior of the nozzle 32 that receives the fuel that will be distributed and finally injected into the air stream to produce a flame. Since the interior of the nozzle 32 acts as a fuel conduit, the shape of the hole, the diameters of the hole, the distribution of the hole and the injection angles all contribute to how the fuel is distributed along the interior of the nozzle 32. The modality shown is only representative, and it is contemplated that other forms, geometric characteristics and indications of the body can be used appropriately. That is, the nozzle can have other curves, tapers, angles and the interior surface and interior geometries, and even with this achieve the objectives of the injection nozzle 16. Likewise, any of the suitable materials can be used in the construction of the injection nozzle 16, although the steel Stainless is a preferred material, among others. The interior surface 34 of the wall of the nozzle 30 defines the interior of the nozzle 32 in which the fuel is received from the fuel line 14. Various connection meanings are possible between the fuel line 14 and the injection nozzle 16 The nozzle body 28 further includes a series of fuel passages 40 ending in holes or holes 42 formed in the wall of the nozzle to distribute the fuel from the inside. Accordingly, fuel flows from the interior of the nozzle 32 through the passages 40 and fiera of the nozzle 16 through the holes 42 in the air flow (see figures 1-2). It is contemplated that the size, shape and placement of the holes and passages can be varied to achieve the desired mixing effect (for example, by mixing between the air flow and the fuel injected into the air). The size of the nozzle holes is important, because if the holes are too small, the problem of contamination or other similar problems may arise. One factor in determining the size, shape, and placement of suitable holes and passages is the position of the nozzle relative to the air flow. Another factor is the geometry of the mouthpiece itself. The placement of holes can be selected to promote mixing by distributing fuel in the prevailing air flow. And the result is that air enters (carried in a stream) into the fuel to achieve better quality mixing. Finally, the goal is to achieve uniform mixing, and it has been found that more uniform mixing results from a wide dispersion of fuel in the air flow. In a modality that is illustrated in figures from 3 to 5, the passages and placement of holes are shown in a representative nozzle. The fuel is injected along the fuel injection direction 40. Representative fuel injection paths are illustrated through arrows 44. More specifically, in one embodiment, the passages may be cylindrical and the holes may be round. Although any hole size is contemplated, in one embodiment the holes can be designed to have a diameter in the range of from about 0.0625 inches to about 0.141 inches (0.1587 to 0.35814 cm). In one embodiment, the holes can be spaced, as measured from their respective centers from about 0.325 to about .75 inches (0.8255 to 1.905 cm) with an example hole distance of 0.5 inches (1.27 cm) apart. In a design goal, select the size, shape and placement of the holes in the nozzle to minimize, substantially eliminate the interference between the holes (e.g., a junction fuel injection direction, in whole or in part, with another fuel injection direction). As shown in Figure 2c, for a given nozzle N, the distance between the holes of an example nozzle is L and the diameter of the holes is D. The L / D ratio will define the ratio between the adjacent holes. The diameter of the holes will determine the depth of fuel penetration (gas) and the general patterns of fuel distribution. L determines whether the adjacent fuel jets result in or combine the fuel streams. As shown in Figure 2d, the fuel penetration depth of the fuel example and the fuel distribution patterns x1 and x2 are illustrated for two holes y and z of different hole diameters. It is contemplated that the size variations, shape and placement of the holes can be from nozzle to nozzle (for example, for a given nozzle the holes and spacings are identical) or the size, shape or placement can vary from hole to hole. In a preferred embodiment, the ratio of L to D is approximately 5. The interaction between the adjacent nozzles (in addition to the staggering of the holes) can be an effective means to carry out the interaction of the fuel jet. In general, it can be said that the counterflow angle (i.e., the angle created by the fuel flow injection direction with respect to the prevailing air flow direction) effects the downstream mixing of the holes. It has been found that ideal mixing conditions occur when the counterflow angle is such that the direction of the fuel flow is not completely opposite to the prevailing air flow direction. The counterflow angle also effects the air / fuel mixing location and allows to control whether or not mixing occurs more or less in a downstream of the nozzles. This can be convenient for a variety of reasons. For example, to keep mixing air and fuel beyond the downstream of the nozzles, the flame can be created beyond the downstream, and the nozzle can be protected from exposure to high levels of heat. This can be used to prevent the nozzles from burning prematurely. Likewise, the size, number and placement of passages and holes in the nozzle body allows the flame to be sculptured (also referred to as flame formation or flame configuration) to achieve optical mixing with regard to the geometry of the furnace. In general, it has been found that when conditions reach a "full counterflow" (ie, when the fuel and air paths are completely opposite each other) a better level mixing can occur, although less control of mixing could be achieved , since the trajectories of the routes will be unpredictable. Likewise, the selection of the backflow angle depends on conditions such as the distribution, direction and speed of the burner air flow. Figure 6 is a perspective view of another embodiment of a counterflow fuel injection nozzle according to an aspect of the present invention. Figure 7 is a side sectional view of the counterflow fuel injection nozzle of Figure 6 and Figure 8 is a sectional view from the bottom taken along line 8-8 of Figure 7. Figures 6 through 8 also illustrate example counterflow injection angles. Referring to Figures 6 through 8, the body of 128 has a nozzle wall 130, and the nozzle wall 130 defines the interior of a nozzle body 132. As shown, the nozzle 116 has generally "truncated T-shape" in that it is truncated when compared to the modality of figures from 3 to 5. It is the interior of the body of the nozzle 132 that receives the fuel and that will be distributed and finally injected into the current of air to produce a flame. Since the interior of the body of the nozzle 132 acts as a fuel conduit, the hole shapes, as with the other embodiments, the hole diameters, the hole distribution and the injection angles, all contribute to how the fuel is distributed. fuel along the inside of the nozzle. The modality shown is representative only, and it is contemplated that other forms, geometric features and body designs could be used appropriately. Likewise, any of the suitable materials can be used in the construction of the injection nozzle 116, although stainless steel is a preferred material, among others. The interior surface 134 of the nozzle wall 130 defines the interior of the nozzle 132 in which the fuel is received from the fuel line 114. The fuel line 114 includes an optional threaded portion 134., for thread insertion into a corresponding thread portion 138 of the inner surface 116 if a threaded connection is desired. Although a threaded socket is preferred, it is contemplated that other means of connection between the fuel line 114 and the injection nozzle 116 are possible. The nozzle body 128 further includes a series of fuel passages 140 ending in holes. or holes 142 formed in the wall of the nozzle to distribute the fuel from the inside. Accordingly, fuel flows from the interior of the nozzle 132 through the passages 140 and out of the nozzle 116 through the holes 142 in an air flow (again see Figures 1 and 2). It is contemplated that the size, shape and placement of the holes and passages can be achieved to vary the desired mixing effect (the mixing between the air and the fuel injected into the air.) Again, the placement of the hole will be selected to promote mixing by distributing the fuel in the prevailing air flow In the illustrated embodiment of Figures 6 through 8, the passages and placement of representative holes are shown in a representative nozzle .The fuel is injected along the directions of representative fuel injections 144. The size and placement of the different passages and holes are similar to those described below in greater detail above with respect to Figures 3 through 5. Figure 9 is a perspective view of another embodiment of the counterflow fuel injection nozzle according to one aspect of the present invention. Figure 9 is the limited footprint shown, so that the nozzle shown could be incorporated into smaller burners, particularly where the insertion of a larger T area or other nozzle formed, may not fit properly in the space provided. Fig. 10 is a side sectional view of the counterflow fuel injection nozzle of Fig. 9. Fig. 11 is a front sectional view taken along line 11-11 of Fig. 10. 9 to 11 illustrate fuel flow injection angles and example angular hole spacing. Referring to figures 9 through 11, the nozzle body 228 has a nozzle wall 230, and the nozzle wall 230 defines the interior of a nozzle body 232. As shown, the nozzle 216 includes various contours defining a groove or groove placed in a primary centralized circumferential shape 233 defining a surface 235. The shape of the nozzle is generally referred to in the present invention as "in the form of mushrooms". It is the interior of the body of the nozzle 232 that receives the fuel that will be distributed and finally injected into the air stream to produce a flame. Since the interior of the body of the nozzle 232 acts as a fuel conduit, the curves, angled tapers and particular surface and interior geometry of the injection nozzle 216, will dictate how fuel is distributed throughout the interior of the body of the nozzle 232. The modality shown is only representative, and it is contemplated that other forms, geometric characteristics and body designs may be used appropriately. Likewise, any suitable materials can be used in the construction of the injection nozzle 216, although steel is a preferred material, among others. The interior surface 234 of the nozzle wall 230 defines the interior of the nozzle 232 in which the fuel is received from the fuel line 214. The fuel line 214 includes a threaded portion 236 for the threaded insert in the with thread 238 of the interior surface 234. Although a thread socket is shown and is preferred, it is contemplated that other means of connection between the fuel line 214 and the injection nozzle 216 are possible. The nozzle body 228 further includes a series of passages 240 ending in holes or holes formed in the nozzle wall. distribute the fuel and more particularly, the holes are formed in the surface 235 of the notch or groove placed in primary centered circumferential shape 233. Accordingly, fuel flows from the interior of the nozzle 232 through the passages 240 and out of the nozzle 216 through the holes 242 in an air flow (again see figures 1 and 2). It is contemplated that the size, shape and placement of the holes and passages may be varied to achieve the desired mixing effect. Here again the placement of the hole will be selected to move the mixing, distributing the mixing in the prevailing air flow. In the modality illustrated in figures 9 to 11, passages and the placement of representative holes are shown in a representative nozzle. The fuel is injected along the fuel injection direction 244. The representative flow injection paths are illustrated with arrows 244. The size and placement of the different passages and holes are similar to those described in detail. above with respect to Fig. 3 to 5. Fig. 12 is a perspective listing of another embodiment of the counterflow fuel injection nozzle 416 according to one aspect of the present invention. Figure 13 is a side sectional view of the counterflow fuel injection nozzle 416 of Figure 12. Figures 12 and 13 also illustrate the fuel injection and counterflow fuel injection paths. Referring to Figures 12 and 13 the nozzle body 428 has a nozzle wall 430, and the nozzle wall 430 defines an interior of the nozzle 432. It is the interior of the nozzle body that receives the fuel that will be distributed and finally injected into the air stream to produce a flame. And that the interior of the body of the nozzle 432 acts as a fuel conduit, the curves, angled tapers and particularized interior surface and geometry of the injection nozzle 416 will dictate how fuel is distributed throughout the interior of the nozzle body 432 Here again, the modality shown is only representative, and it is contemplated that other forms, geometric characteristics and body designs can be used appropriately. Again, any of the suitable materials can be used in the construction of the injection nozzle 416, although stainless steel is a preferred material, among others. The inner surface of the wall 434 of the nozzle wall 430 defines the interior of the nozzle 432 in which the fuel is received from the fuel line 414. The fuel line 414 includes the threaded portion 436 for the insertion with threaded into a corresponding threaded portion 438 of the inner surface 434. Although a threaded socket is shown and preferred, it is contemplated that other means of connection between the fuel line 414 and the injection nozzle 416 are possible. The body of the nozzle 428 further includes a series of fuel passages 440 terminating in holes or holes 442 formed in the wall of the nozzle 430, and more specifically, the slot 433 distributing the fuel. The slot 433 prevents air from cutting off the gas leaving the holes and allows the gas to develop in a jet stream, resulting in more consistent mixing. Fuel flows from the interior of the nozzle 432 through the passages 440 and out of the nozzle 416 through the holes 442 in an air flow (again see Figures 1 and 2). It is contemplated that the sizeThe shape and placement of the holes and passages can be varied to achieve the desired mixing effect. Again, the placement of the hole can be selected to promote mixing, distributing the fuel in prevailing air flow. In the embodiment illustrated in Figures 12 and 13, passages and placement of representative holes in a representative nozzle are shown. Fuel is injected along the fuel injection direction 444. In one embodiment of the counterflow fuel injection nozzles illustrated in Figures 12 and 13, the passages may be cylindrical and the holes may be round. Although any hole size is contemplated in one embodiment, the holes may be designed to have a diameter in the range of from about 0.0625 inches to about 0.141 inches (0.15875 to 0.35814 cm). The angular spacing of the hole ranges of one embodiment is from about 45 degrees to about 60 degrees. It is contemplated that variations in size, shape and placement may be on a base of hole by hole and / or nozzle by nozzle. However, it will be understood that it is a design goal selected from the size, shape and placement of the holes to minimize or eliminate interference between the fuel flow paths of the holes (eg, a fuel injection direction junction, totally or in part, with another direction of fuel injection). The pattern of holes (for example, the number and position of the holes) as well as the size of the hole (for example, as determined by the hole diameter) can be varied. In this form, mixing of air and fuel can be achieved to control and thereby achieve a substantially complete complete combustion, a characteristic seal of the present invention. Referring now to Figures 14 and 15, another embodiment of the counterflow fuel injection nozzle 500 is shown in accordance with an aspect of the present invention. In this embodiment, the nozzle 500 includes an external threaded surface 502 with a retention nut 504 threaded therein to secure the nozzle 500 against the burner receiving portion 506, such as by fitting the groove 507 in a suitable manner. and the rotation nozzle 500. The nozzle 500 includes a perforated external portion, channel or passage 508 (shown in phantom line) terminating in the nozzle orifice 509. Fuel enters the fuel passage 508 in a direction indicated by the arrow 512 and proceeds through passage 508, where it flows out of the nozzle in an air flow through nozzle orifice 509. The fuel is injected in the injection direction of the fuel flow (Fcombus, bie) and in a prevailing air direction (Faire) - Again, the fuel is injected through the orifice of the nozzle 509, so that at least one Fusible component is opposite to Faire.

More localized mixing may occur in each counterflow injection nozzle, and more specifically, through the holes through which it is distributed or dispersed from each nozzle within the prevailing air flow. In this mode the amount or level of mixing, as well as the location (s) in which mixing takes place, can be adjusted or varied for convenience, and by varying the size and location of the holes. It is contemplated that each of the above-described embodiments of the counterflow fuel injection nozzles of the present invention may include a plurality of passages, each having a fuel injection direction without unique interference. By the term "without interference" is meant that, at the point at which the fuel leaves the nozzles (through the orifices of the nozzle) the fuel coming from a passage having a directional tendency that does not cross the direction of the passage of fuel from the other passage. The holes can also be directed at various angles to achieve the desired mixing qualities. In another aspect of the present invention, the method for mixing a fuel and air in a burner-boiler system is described. The system comprises a nozzle having a nozzle wall defining the interior of a nozzle that receives the fuel, and the nozzle further includes a fuel passage formed in the wall of the nozzle. The method comprises passing air in an air current direction prevalent along the exterior of the nozzle wall. The method further includes distributing the fuel in a direction of fuel flow injection from the interior through the fuel passage in the air passage in the direction of air flow prevailing along the exterior of the nozzle wall. The method further includes mixing counterflow the fuel distributed in the direction of fuel flow injection with the air passing in the prevailing air current direction. Significantly, at least one vector component of the fuel injection and flow direction is opposed to at least one vector component of the prevailing air flow direction. Likewise, the use of the counterflow nozzle provides stability of the additional burner with increased ranges of chimney-gas smoke re-circulation (FGR) (when using FGR) to achieve lower NOx levels. As known to those skilled in the art, the return ratio is the ratio of the maximum fuel input range to the minimum fuel range of a variable input burner, and depends on the size of the burner and control methodology. Typical NOx-level burners have limited turns, but the present invention, conveniently, with the low-NOx low-level operation a larger turn-up ratio, and a turn of about 7 to 1 to about 10 is possible. a 1 has been achieved using the counterflow injection nozzles of the present invention. It should be noted that it contemplates a retro-adjustment of the gas mixing nozzle for a burner used with a fire tube boiler, commercial water pipe boiler or larger industrial water pipe boiler. The retro-adjustment can be part of a team that includes a counterflow fuel injection nozzle that is used to replace a fuel injection no-backflow nozzle. A fuel injection no-counterflow nozzle may not provide at least one vector component of a fuel flow injection direction that is set to at least one vector component of a prevailing air flow direction when a stream of air is supplied. air in a direction of prevailing air flow at an outside location of the nozzle. According to another aspect, the present invention provides a counterflow fuel injection nozzle for injecting a gaseous fuel. The nozzle comprises a wall of the nozzle having an interior surface defining the interior of a nozzle and the interior receiving a fuel therein. The nozzle further includes a plurality of fuel passages formed in the wall of the nozzle to distribute the fuel from the interior to an exterior location of the nozzle, and the fuel is distributed to the outside location in a direction of fuel flow injection . Subsequently, an air stream is provided in a prevailing air flow direction at the outer location of the nozzle, at least one vector component of the fuel flow injection direction in opposite manner to at least one vector component of the direction of prevailing air flow. In at least some embodiments (e.g., "T-shaped" or "head-type" modes), the counterflow fuel injection nozzle may have at least one of the fuel passages ending in an orifice that have a diameter within a range from approximately .063 inches to approximately .189 inches (0.16 to 0.48 cm). In at least some embodiments (e.g., in the "T-Shape" or "Hammerhead type" embodiments), the counterflow fuel injection nozzle may have a hole having a diameter of approximately 0.1875 inches (0.47625 cm). ). In other embodiments, the counterflow fuel injection nozzle is used to generate steam and / or hot water. In still other embodiments, the counterflow fuel injection nozzle is used in a combustion apparatus. According to yet another aspect of the present invention, a combustion apparatus is described. The combustion apparatus includes a plurality of radially placed lances, each of the lances connected to at least one of the plurality of counterflow fuel injection nozzles for injecting a gaseous fuel. In at least some embodiments, each injection nozzle includes a nozzle wall having an interior surface defining the interior of a nozzle, and the interior residing all of the fuel therein. In at least some embodiments, each nozzle further includes a plurality of passages formed in the wall of the nozzle to distribute fuel from the interior to a location on the outside of the nozzle, and the fuel is distributed to the outside location in an injection direction of fuel flow. Conveniently, when an air stream is provided in a prevailing air flow direction at the outer location of the nozzle, at least one vector component of the fuel flow injection direction is opposite to at least one Vector component of the prevailing airflow direction. Although the methods are indicated in a step-by-step sequence, the completion of the actions or steps in a particular chronological order is not mandatory. In addition, modifications, readjustments, combinations, rearrangements and the like of the actions or steps are contemplated and considered within the scope of the description and appended claims. Although the present invention has been described in terms of a modality (s), it is recognized that equivalents, alternatives and modifications are possible and are within the scope of the appended claims, in addition to those expressly stated in the present invention.

Claims (6)

R E I V I N D I C A C I O N S

1. A fuel injection nozzle of the backflow for injecting a gaseous fuel, characterized in that the nozzle comprises: a nozzle wall having an interior surface defining the interior of a nozzle, the interior receiving a fuel therein, wherein the The nozzle further has a plurality of fuel passages formed in the wall of the nozzle to distribute the fuel from the interior to an exterior location of the nozzle, wherein the fuel is distributed to the outside location in a direction of fuel flow injection; wherein when an air stream is provided in the prevailing airflow direction at the outer location of the nozzle, at least one vector component of the flow injection direction is in opposite manner to at least one vector component of the flow vector. the direction of prevailing air flow.

The counterflow fuel injection nozzle as described in claim 1, characterized in that at least one of the fuel passages terminates in an orifice having a diameter in the range of between about .063 inches and about. 189 inches (0.16 to 0.48 cm).

3. The counterflow fuel injection nozzle as described in claim 2, characterized in that the orifice has a diameter of approximately 0.1875 inches (0.47625 cm).

4. The counterflow fuel injection nozzle as described in claim 3, characterized in that the nozzle is used to generate steam and / or hot water.

5. The counterflow fuel injection nozzle as described in claim 4, characterized in that the nozzle is used in a combustion apparatus.

6. A combustion apparatus comprising: a plurality of radially placed lances wherein each of the lances is connected to at least one of a plurality of counterflow fuel injection nozzles for injecting a gaseous fuel; wherein each of the injection nozzles includes: a nozzle wall having an interior surface defining the interior of a nozzle, wherein the interior is for receiving fuel therein, and each of the nozzles further includes a plurality of fuel passages formed in the wall of the nozzle to distribute the fuel from the interior to an exterior location of each nozzle, wherein the fuel is distributed to the exterior location in a fuel flow injection direction; and wherein, when an air stream is provided in a prevailing air flow direction at the outer location of each of the nozzles, at least one vector component of the fuel flow injection direction is opposite to the less to a vector component of the prevailing air flow direction. R E S U M E N A counterflow fuel injection nozzle is described for injecting fuel. The nozzle includes a nozzle wall having an interior surface defining the interior of a nozzle, wherein the interior receives fuel therein. The nozzle further has a fuel passage formed in the wall of the nozzle to distribute the fuel from the interior to an exterior location of the nozzle, wherein the fuel is distributed to the outside location in a direction of fuel flow injection. An air stream is provided in a prevailing air flow direction at the outer location of the nozzle. At least one vector component of the fuel flow injection direction is opposite to at least one vector component of the prevailing air flow direction. In this way, by distributing the fuel in an air flow at a counterflow angle, improved control of the mixing of the fuel in the air is achieved. The backflow nozzle can be included as part of a new burner or as a retro-adjustment for the exit of the burners in order to incorporate backflow mixing. Conveniently, the burner turns proportions and stability are improved through the use of counterflow fuel injection nozzles with burners that use FGR (for example, having low 02 level in the combustion air supplied to the burner).