MXPA98010533A - A method for carrying out a control on a burner with a flat nucleo radialmente estratific - Google Patents

Abstract

The present invention relates to a method for controlling a radially stratified flame core burner installed in a burner furnace with fossil fuel, the method characterized in that it comprises the steps of: a) providing a furnace that has been installed with it , a radially stratified flame core burner, b) establish an external area of air flow as a result of the injection of a first portion, of the total amount of air required combustion of fossil fuel, which is burned through the operation core, of radially stratified flame, c) establish an inner zone of air flow and a fossil fuel, as a result of the injection of a second portion, of the total amount of air required to effect the combustion of fossil fuel, which burns through the operation of the radially stratified flame core burner d) establish a plurality of different types e flame, that the radially stratified flame core burner, is capable of producing, with the same predetermined volume of air injected into the interior zone as the second portion of the total amount of air, of flame including controlling the angular momentum of the injected air in the inner zone by mechanical means, which do not vary the predetermined volume of the injected air and control the injection angle of the fossil fuel injected into the inner zone, a first type, of the plurality of different types of flame, is a type of flame that it has a complete injection of the fossil fuel injected into the inner zone, a first type, of the plurality of different types of flame, is a type of flame that has a very short flame length, characterized by a very short flame and well stirred, with high volumetric heat evolution and that works to produce thus, the highest level of NOx of any of the plurality of different types of flames, and still a level of NOx that is still able to satisfy state and federal requirements, a second type, of the plurality of different types of flame, is a type of flame that has a medium flame length, which characterized by a medium flame with a moderate degree of turbulent flow and which works to produce well, low NOx, low CO and low opacity, and a third type, of the plurality of different types of flame, is a type of flame that has a long flame length, which is characterized by a long flame with a lower degree of turbulent flow, than any other of the plurality of different types of flames and which functions to produce low, high NOx, high CO and high opacity; e) set the depth of the furnace having a core burner, of radially stratified flame installed therein, being of a specific depth, selected from a plurality of different depths, the first, of the plurality of depth s different, is a depth that is short in length, a second, of the plurality of different depths, is a depth that is medium in length, and a third, of the plurality of different depths, is a depth that is long and f) selecting, based on the establishment of the depth of the furnace, having the radially stratified flame core burner, installed therein, according to e), one, of the plurality of different types of flame, which has a length corresponding to the depth of the furnace, in such a way that if the depth of the furnace is short, the type of flame selected from the plurality of different types of flame, is the type of flame that has a very short length and if the depth of the furnace is medium, the type of flame selected from the plurality of different types of flame, is the type of flame that has a medium length and if the depth of the furnace is long, the type of flame selected of the plurality of different types of flame, is the type of flame that has a long length with the same predetermined volume of air, which is being injected into the interior zone, independent of one, of the plurality of different types of flame that I was selected

Description

A BACKGROUND OF THE INVENTION This invention relates to radially stratified flame core burners, which are used in the combustion systems of fossil fuel operated furnaces, and more specifically, to a method for effecting control over a "radially flared core burner". stratified Fossil fuels have been "burned successfully in furnaces for a long time. Although recently, more and more emphasis has been placed on the possible reduction of air pollution. This connection, with reference in particular to the matter of NOx control, is known that during the combustion of fossil fuels in furnaces, nitrogen oxides are created. Furthermore, it is also known that these nitrogen oxides are created primarily by two separate mechanisms, which have been identified as thermal NOx and fuel NOx. Continuing, thermal N0X results from the thermal fixation of nitrogen and molecular oxygen in the air, which is used in the course of combustion of the fossil fuel. The rate of thermal N0X formation is extremely sensitive to the local flame temperature and somewhat less than the local oxygen concentration. Virtually, All thermal N0X is formed in the region of the flame that is at the highest temperature. The thermal N0X concentration subsequently "freezes" to the predominant level in the high temperature region by the thermal neutralization of the combustion gases. The thermal N0X concentrations of combustion gases are therefore between the characteristic equilibrium level of the peak flame temperature and the equilibrium level at the temperature of the combustion gases. On the other hand, N0X of the fuel is derived from the oxidation of organic bound nitrogen in certain fossil fuels such as mineral coal and heavy oil. The rate of NOx formation of fuel is strongly affected by the mixing speed of the fossil fuel and the air stream in general and by the local oxygen concentration in particular. However, the NOx concentration of combustion gases due to nitrogen in the fuel, typically only a fraction; for example 20 to 60 percent, of the level that would result from complete oxidation of all the nitrogen in the fossil fuel. In this way, it should now be readily apparent from the foregoing that total NOx formation is a function of both local oxygen levels and peak flame temperatures. Over the years, there have been different approaches that are carried out in the prior art in relation to addressing the need to limit N0X emissions that are created as a consequence of the combustion of fossil fuels in kilns. The focus has been on developing so-called low N0x burn systems for use in furnaces operated with fossil fuels. By way of exemplification and not limitation in this aspect, an example of this low N0X burn system is that which forms the subject of the US patent. No. 5,020,454 titled "Clustered Concentric Tangential Firing System", granted on June 4, 1991 and assigned to the same transferee as the present patent application. In accordance with the teachings of the U.S. patent. No. 5,020,454, there is provided a tangential burner system concentric in battery that includes a wind box, a first battery of fuel nozzles mounted in the wind box and operative to inject fuel in battery to the furnace in order to create a first zone rich in fuel, a second battery of fuel nozzles mounted in the wind box and operative to inject fuel into battery in the furnace, to create a second fuel-rich zone, a displaced air nozzle that mounts in the windbox and operative to inject air displaced to the furnace, in such a way that the displaced air is directed away from the fuel in battery that is injected into the furnace and towards the walls of the furnace, a secondary air nozzle close coupling, mounted in the windbox and operative to inject combustion overburner air closed to the furnace, and a separate secondary air nozzle is mounted in the windbox and operative to inject secondary air separated to the furnace. Another example of such a low N0X burn system is that which forms the subject matter of US Pat. No. 5,315,939, entitled "Integrated Low N0X Tangential Firing System", granted on May 31, 1994, and "granted to the same transferee" as the present patent application. In accordance with the teachings of the U.S. patent. No. 5,315,939, an integrated low N0X tangential burner system is provided which includes solid pulverized fuel supply assemblies, sprayed solid fuel jet fuel nozzle tips, concentric burner keels, secondary air of close coupling and Secondary multi-stepped secondary air and when used with a solid fuel pulverized firing furnace, is capable of limiting N0X emissions to less than .269 kg / 106 kcal. (0.15 lb./106 BTU) while still maintaining coal-in-fly ash at less than 5% and CO emissions at less than 50 ppm. Yet another example of this low NOx burn system is that which forms the subject matter of the U.S. patent. No. 5,343,820, titled "Advance Overfire Air System for N0x Control "(Advanced Secondary Air System for Control of N0X), granted on September 6, 1994, and which was granted to the same assignee as the present patent application, In accordance with the teachings of US Patent No. 5,343,820 , an advanced secondary air system for N0X control is provided which includes multiple elevations - of secondary air compartment to which secondary air is supplied, such that there is a more favorable predetermined distribution of secondary air between them, so that that the secondary air exiting the separated secondary air compartments establishes a horizontal "spray" or "fan" distribution of secondary air leaving the separated secondary air compartments at speeds significantly higher than the speeds used to date. approach that has been sought in the prior art to address the need to limit N0X emissions that are It has been created as a consequence of the combustion of solid fuels in furnaces, has developed the so-called "low NOx burners that are suitable for integration in the burning systems used in furnaces operated with fossil fuels. By way of exemplification and not limitation in this regard, an example of this low N0X burner is "what forms the subject matter of US Pat. No. 4,422,931 titled "Method Of Combustión Of Pulverized Coal By Pulverized Coal Burner ", awarded on December 27, 1983 and assigned to Kawasaki Jukogyo Kabushiki Kaisha from Kobe, Japan, according to the teachings of the Coal Burner. US Patent No. 4,422,931, a low N0X burner is provided wherein the pulverized coal is supplied together with primary air through a combustion air outlet of the low N0X burner and caused by a turbulent, is injected into the furnace while it flows slowly in a vortex form, secondary air is injected into the furnace with exhaust gas through an inner annular outlet that surrounds the combustion air outlet, the secondary air either slowly circulates in a vortex or does not circulate in a vortex as the case may be, tertiary air is injected into the furnace with exhaust gas through an outer annular outlet that surrounds the inner annular outlet while circulates in a vortex form. Powdered charcoal supplied to the furnace together with primary air is burned to form a primary flame. The primary flame is formed by slow combustion of pulverized coal at low temperature with low 02 and is low in brightness, because the primary air is approximately 20-30% in the amount of air needed to burn all the pulverized coal that is supplied to the oven and it is forbidden to mix secondary and tertiary air. The combustion of a volatile component of pulverized coal is Primarily responsible for the formation of the primary flame, so that the pulverized coal burns slowly at low temperature with a flame of low brightness. In this type of combustion, N0X production is greatly produced and unburned components such as hydrocarbons which are active intermediates responsible for the denaturing reaction, NH3, HCN and CO, are produced in large quantities and exist for a prolonged period of time. time in a non-burned condition. In this way, these unburned components react with N0X in N2.

The char that is produced in large quantities as a 'unburned component of the primary flame, it' burns in the secondary flame. The residual volatile component is burned primarily by secondary air that is expelled through the inner annular outlets to form a secondary flame. Most charring is burned by secondary air and tertiary air to form a tertiary flame range. The secondary flame and the tertiary flame are formed by the combustion at relatively low speed and low temperature with low 02, due to "that the secondary and tertiary air is approximately 55-80% in quantity of the air necessary for the combustion of all the coal pulverized and the air contains exhaust gas in 35-60%. Another example of this low N0X burner is that which forms the subject of the US patent. No. 4,545,307 with title "Apparatus For Coal Combustion" (Apparatus for Combustion of Mineral Coal or Coal), granted on October 8, 1985 and that in its cover was assigned to Babcock-Hitachi Kabushiki Kaisha of Tokyo, Japan. In accordance with the teachings of the U.S. patent. No. 4,545,307, a low Ñ0X burner is provided which includes a pulverized coal-mineral pipe, inserted in a burner throat in the side wall of a combustion furnace and for feeding the coal and air to the furnace, a means for Feed the coal and air coal coal pipeline, a secondary air passage formed between the coal coal pipeline and a secondary air feed pipe that is provided on the outer peripheral side of the coal pipeline coal, a tertiary air passage formed in the outer peripheral side of the secondary air supply pipe, and means for feeding air or a gas containing oxygen in the secondary air passage and the tertiary air passage, and a body not fuselage that has a cross section in the form of letter L that is provided at the tip of the mineral coal pipe. Yet another example of this low NOx burner is that which forms the subject matter of US Pat. No. 4,539,918 entitled "Multiannular Swirl Combustor Providing Particulate Separation" of Multianular Whirlpool Compound that Provides Particle Separation granted on September 10, 1985 and assigned to its title page.

Westinghouse Electric Corp. According to the teachings of the U.S. patent. No. 4,529,918, a low N0X burner is provided which includes a plurality of tubular members having different axial lengths and arranged to form a basket of burners of sufficient axial size and length to contain rich and poor combustion zones, axially spaced, medium for holding the tubular members substantially coaxially and telescopically to each other to provide a generally annular path for gaseous reactants at inlet pressure or pressurized air flowing in the low N0x burner, with predetermined axial velocity between each tubular member and the next tubular member arranged radially outward, means for imparting a tangential velocity to the gaseous reactant "entering the" low N0X burner through each annular flow path, with the tangential velocity of at least the flows entering the rich combustion zone that it increases with increased radius of flow, nozzle means for supplying fuel to the low N0X burner at least at a predetermined location, the tubular members have respective axial sections and are arranged such that the axial location of the outlet ends of the tubular member generally have increased radii and respectively they are located in successive downstream sites, the means that impart tangential velocity and the radial and axial geometry of at least two of the tubular members, are coordinated under conditions of axial gas velocity and inlet gas pressure operative to: a) define the rich combustion zone in a portion upstream of the low N0X burner, where deficient combustion of oxygen at high temperature occurs, with recirculation flow of flame stabilizer and substantially without formation of net N0X and b) produce a toroidal vortex in the rich combustion zone, with recirculating combustion air that is recuperatively supplied in a substantial manner by vortex inlet air flow, after "which has cooled the inner wall surfaces of the tubular members with respect to the rich combustion zone and c) provide sufficient residence time of fuel particles in the rich combustion zone" , to allow «burning of particles before centrifugal separation of the particles towards the super The wall of the low NOx burner, the means imparting tangential velocities and the radial and axial geometry of at least two of the tubular members located outwardly from the tubular members with respect to the rich combustion zone, are coordinated under operating conditions. of axial gas velocity and inlet gas pressure to define the poor combustion zone and to produce a toroidal vortex in the poor combustion zone, the tubular members are arranged to provide a throat section in which the rich combustion zone converges and from which the poor combustion zone diverges, and means for collecting and removing the combustion particles separated from the flow as it passes through the throat section. Yet another example of this low N0X burner is that which forms the subject matter of US Pat. No. 4,845,940, with the title "Low NOx Rich-Lean Specially Useful Combustor In Gas Turbines", granted on July 11, 1989, and which will be assigned to Westinghouse Electric Corp. According to the teachings of the US patent No. 4,845,940, a low NOx burner is provided which includes tubular wall means having at least three successive tubular wall portions, disposed in successive downstream locations and having respectively increased dimensions in the radial direction, to provide an enclosure of divergent combustor outwardly generally on the axial direction defining the diverging combustion zones outwardly for low N0X combustion, means for supporting the tubular wall portions together, to provide a rigid structure for the "low N0X burner, means of nozzle to supply fuel to the low N0X burner at least at a predetermined location, each successive pair of adjacent tubular wall portions is structured to defining a generally annular inlet flow path extending in the radial direction between the outer surface of the upstream wall portion radially inward of the pair and the inner surface of the downstream wall portion radially outward of the pair and further extends downward in the axial direction on the inner surface of the downstream wall portion radially outwardly of the pair, such that successive annular flow paths overlap axially to allow the annular flows to combine at least partially to form Whirlwind of flow radially inward in the combustion zone, the wall portions are further dimensioned and structurally coordinated, such that "the total annular air flow substantially includes all the inlet air flow under pressure" intended to complete burned fuel in the combustion zone unlike any other Nozzle atomization air or other special air flow "that can be provided and in such a manner that the combustion air flows inward at a rate required to support rich combustion over the axial region of the combustion zone, allowing this way poorer combustion radially outwardly and axially downwardly within the combustion zone, first whirling means for imparting a tangential velocity to the inflow of air through the first annular flow path radially innermost, second vortex means for imparting a tangential velocity to the inflow of air through the second annular flow path located radially outwardly and axially downwardly of the first annular flow path, the first and second means of whirlwind are inter-related to produce a negative radial gradient in the tangential velocities of the incoming air flows through the first and second annular trajectories, and the tangential velocities decrease with increasing radius and are operative within the divergent envelope of the combustion zone, under operating conditions of axial gas velocity and inlet air pressure, to produce a depression of the axial velocity in the combustor shaft substantially with all the combustion air "which is supplied in a recuperative form by the flows of vortex vortex entry, after cooling the interior surfaces of the wall portions that define the combustion zone. A still further example of this low N0X burner is that which forms the subject matter of US Pat. No. 5,411,394 titled "Combustion System for Reduction of Nitrogen Oxides" (Combustion System for Reduction of Nitrogen Oxides), granted on May 2, 1995 and assigned to the Massachusetts Institute of Technology on its cover. In accordance with the teachings of the U.S. patent. Do not. ,411,394, a low N0X burner is provided for the combustion of gaseous, liquid and solid fuels, characterized by the fact that the fluid dynamic principle of the radial stratification by the combustion of vortex flow and a strong radial gradient of the gas density in the direction transverse to the axis of flow rotation is used to dampen turbulence near the burner and therefore to increase the residence time of the fuel-rich pyrolyzing mixture, before mixing with the remainder of the combustion air to effect complete combustion. Despite the fact that over the years there have been different approaches sought in the prior art in regard to addressing the need to limit NOx emissions that is created as a result of the combustion of fossil fuels in furnaces, there is still a need in the prior art to improve on what has been achieved to date following these different approaches. More specifically, low NOx burn systems constructed in accordance with the teachings of the three US patents. Issues relating to low NOx burn systems to which reference has been previously made, have been shown to be operative for the purpose for which they were designed. Similarly, low N0X burners constructed in disagreement with the teachings of the five U.S. patents. issued concerning low N0X burners to which reference has been made with prior, they have proven to be operative for the purpose for which they were designed. In particular, although low N0X burners of the type forming the subject matter of US Pat. No. 5,411,394, ie the so-called core burners with radially stratified flame, have been shown to be operative for the purpose for which they were designed, however there has been a need for further improvements regarding said core burners with radially stratified flame. . More specifically, there has been evidence in the prior art of necessity to be able to control a radially stratified flame core burner. For this purpose, furnaces where the combustion of fossil fuels is carried out, not all incorporate the same depth. Thus, although radial stratification can be achieved provided that the furnace in which the radially stratified flame core burner is employed incorporates a predetermined depth, if the furnace where it is desired to employ a radially stratified flame core burner, however incorporates a depth compared to the predetermined depth previously referred, then there is a need to be able to control the burner with a radially stratified flame core, in such a way that the reduction in N0X emissions that is sought through the use of the Burner with radially stratified flame core can nevertheless still be achieved. To summarize up to this point, a need has been demonstrated in the prior art for a new and improved method to control a core burner with a radially stratified flame, such that "regardless of the depth a furnace may incorporate, the burner of core with radially stratified flame will still be effective to allow reduction in emissions of NOx, which is sought to achieve. Furthermore, it should not only be possible when this new and improved method is used to control a core burner with a radially stratified flame, to achieve this reduction in NOx emissions regardless of the depth the furnace incorporates, but this reduction in NOx emissions should also be achievable while still at the same time the following benefits, which serve to characterize a radially stratified flame core burner, are still capable of being derived through the use of the radially stratified flame core burner. A benefit such as a radially stratified flame core burner, which is controlled by said new and improved method to effect control over a radially stratified flame core burner, is still capable, without the use of flue gas recirculation or secondary air for reduce N0X emissions to a level that allows that the state and federal limits of N0X are met. A second benefit is that a radially stratified flame core burner, which is controlled by said new and improved method to effect control over a radially stratified flame core burner, is capable of achieving N0X values of less than 0.448 kg / MM kilocalories (0.25 l / MM BTU) while burning fuel oil No. 6. A third benefit is that a radially stratified flame core burner, which is controlled by this new and improved method to control a radially stratified flame core burner, incorporates the ability to adjust the angular momentum and derive the air flow there. A fourth benefit is that a radially stratified flame core burner, which is controlled by this new and improved method for controlling a radially stratified flame core burner, is characterized by the fact that its operating mechanisms are positioned in such a way that protect from the radiated heat of the oven. A fifth benefit is that a radially stratified flame core burner, which is controlled by means of this new and improved method to control a radially stratified flame core burner, possesses multi-fuel capabilities, i.e. coal, natural gas and coal mineral A sixth benefit is that a radially stratified flame core burner, which is controlled by this new and improved method for effecting control over a radially stratified flame core burner, is capable of being integrated into virtually any new or existing combustion burner system. A seventh benefit is that a radially stratified flame core burner, "which is controlled by a new and improved method to control a radially stratified flame core burner, is capable of being modified in series production to virtually any boiler design. . An eighth benefit is that a radially stratified flame core burner, which is controlled by this new and improved method to control a radially stratified flame core burner, has a nominal burner thermal rating from .253 MM kilocalories per hour (1 MM BTU per hour). A ninth benefit is a radially stratified flame core burner, which is controlled by said new and improved method to effect control over a radially stratified flame core burner, which allows high grade materials to be selected for use in this way resolve the thermal and / or corrosion aspects. Therefore, an object of the present invention is to provide a new and improved method for effecting control over a radically stratified flame core burner. A further objective of the present invention is to provide said new and improved method for effecting control over a radially stratified flame core burner, in such a way that regardless of the depth that an oven can incorporate, the radially stratified flame core burner will still be effective to allow the reduction in N0X emissions to be achieved. Another object of the present invention is to provide this new and improved method for effecting control over a radially stratified flame core burner, wherein the radially stratified core burner is still capable without the use of recirculation of combustion gases or secondary air, to reduce emissions to a level that allows compliance with state and federal limits for N0X. Still another object of the present invention is to provide this new and improved method for effecting control over a radially stratified flame core burner, wherein the radially stratified flame core burner is capable of achieving N0X values of less than 0.448 kg / MM kilocalories (0.25). Ib./MM BTU) while burning fuel oil No. 6. Another objective of the present invention is to provide said new and improved method for effecting control over a radially stratified flame core burner incorporating the capabilities of adjusting its angular momentum and with he derive the air flow.

A still further objective of the present invention is to provide this new and improved method for effecting control over a radially stratified flame core burner wherein the "radially stratified flame core burner is characterized by the fact that its operating mechanisms are positioned to protect itself. of heat radiated from the furnace. A further objective of the present invention is to provide said new and improved method for effecting control over a radially stratified flame core burner wherein the radially stratified flame core burner possesses capabilities for multiple fuels, ie oil, natural gas and coal. A still further object of the present invention is to provide this new and improved method for effecting control over a radially stratified flame core burner, wherein the radially stratified flame core burner is capable of being integrated into virtually any new combustion burning system or existing. The present invention has as an additional objective to provide this new and improved method to effect control over a radially stratified flame core burner, wherein the radially stratified flame core burner is capable of being modified in series production to virtually any boiler design. .

A still further object of the present invention is to provide this new and improved method for effecting control over a radially stratified flame core burner, wherein the radially stratified flame core burner has a nominal burner thermal rating from .253 MM kilocalories per hour (1 MM BTU per hour). Yet another object of the present invention is to provide this new and improved method for effecting control over a radially stratified flame core burner, wherein the radially stratified flame core burner allows high grade materials to be chosen so as to be employed in this way solve with it aspects of heat and / or corrosion. COMPENDIUM OF THE PRESENT INVENTION In accordance with the present invention, there is provided a method for effecting control over a radially stratified flame core burner, which is particularly suitable for use in a burning system of a fossil fuel burning furnace, for to reduce N0X emissions from the furnace burned with fossil fuel. Furthermore, the present method for controlling a radially stratified flame core burner allows the above to be achieved while at the same time minimizing CO emissions and the opacity of the exhaust from the furnace chimney burned with fossil fuel without extending the envelope of the flame produced by the core burner with radially stratified flame. The current method to control a radially stratified flame core burner where the radially stratified flame core burner is to be installed in a furnace burned by fossil fuel and when installed is operational for purposes of reducing N0X emissions from the furnace burned with fossil fuel, comprising the steps of: determining the depth of the furnace in which the radially stratified flame core burner is to be installed, establishing the permissible length of the flame that the radially stratified flame core burner is capable of producing with a function of the depth of the furnace «burned with fossil fuel, where the radially stratified furnace is to be installed, establishing an outer area of coaxial air flow but spaced from the central line of the core burner with radially stratified flame as a consequence of the injection of 60 to 80% of the total air required for effect the combustion of the fossil fuel "burned through the operation of the radially stratified flame core burner, establishing an interior zone of air flow and fossil fuel flow coaxial with the center line of the radially stratified flame core burner as a consequence of the injection of the rest of the total air required to effect the combustion of the burning fossil fuel through the operation of the core burner with radially stratified flame and as a consequence of the injection of the fossil fuel that is burned through the operation of the radially stratified flame core burner, and virtual control over the length of the flame produced by the burner radially stratified flame core, by controlling the angular momentum of the air injected into the interior zone and controlling the injection angle of the injected fossil fuel to the interior zone in such a way that the length of the flame produced by the flame core burner radially stratified is not greater than the permissible length of the flame that has been established by the furnace burned with fossil fuel in which the radially stratified flame core burner is to be installed. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic illustration of a first type of flame that is capable of being produced with the method for effecting control over a radially stratified flame core burner of the present invention; Figure 2 is a schematic illustration of a second type of flame that is capable of being produced with the method for effecting control over a radially layered flame core burner of the present invention; Figure 3 is a schematic illustration of a third type of flame that is capable of being produced with the method to effect control over a radially stratified flame core burner of the present invention; Figure 4 is a graph of gas stoichiometry versus residence time for each of the types of flames illustrated in Figures 1, 2 and 3, respectively. Figure 5 is a perspective view of a first embodiment of a radially stratified flame core burner that is capable of being controlled by the method for effecting control over a radially layered flame core burner of the present invention, - Figure 6 is a side elevational view partly in section of the first radially stratified flame core burner embodiment illustrated in Figure 5; and Figure 7 is a side elevational view of a second embodiment of a radially stratified flame core burner that is capable of being controlled by the method of effecting control over a radially laminated flame core burner of the present invention. DESCRIPTION OF THE PREFERRED MODALITY Now with reference to the drawing, and more particularly to Figures 1, 2 and 3 thereof, various types of flames are schematically illustrated, "which are capable of being produced with the method to effect control over a core burner of radially stratified flame according to the present invention.

That is, in Figure 1 of the drawing, a first type of flame, generally denoted by the reference number 10, is schematically illustrated. In Figure 2 of the drawing, a second type of flame, generally denoted by the number of the flame, is illustrated schematically. reference 12. In Figure 3 of the drawing, a third type of flame, generally denoted by the reference number 14, is schematically illustrated. For purposes of facilitating a better understanding of the types of flame illustrated, it is "chemically in each of Figures 1, 2 and 3 of the drawing, the air, which as will be described more fully below, is injected into the outer zone to which greater reference will be made next, is generally denoted in each of Figures 1, 2 and 3 by the same reference number, ie the reference number 16. Likewise, the rest of the air, which as will be described more fully below, is injected into the interior area to which ref Further in the following, it is generally denoted in each of Figures 1, 2 and 3 by the same reference number, ie the reference number 18. Finally, the fossil fuel, which as will be more fully described below, is injected into the inner area to which further reference will be made below, is generally denoted in each of Figures 1, 2 and 3 by the same reference number, ie the reference number 20.

Reference will now be made to Figure 4 of the drawing, which is a graph of the gas stoichiometry against the residence time associated with each of the types of flame "which are illustrated schematically in Figures 1, 2 and 3 of the drawing. . For purposes of your discussion, a type of flame is considered to have a short flame length or a long flame length or average flame length, based on the amount of residence time it takes for a leveling to occur. the gas stoichiometry. That is, the faster a leveling of the gas stoichiometry occurs, the shorter the flame length. Thus, in accordance with the foregoing, as best understood with reference to Figure 4, wherein each of the types of flames illustrated schematically in each of Figs. 1, 2 and 3 are illustrated, the type of flame 14 will be considered here representative of a type of flame having a short flame length, in comparison with the flame length of the types of flames 10 and 12. Likewise, the flame type 10 will be considered representative here of a type of flame having a long flame length, compared to the flame length of flame types 12 and 14, while flame type 12 will be considered here representative of a type of flame "having a average flame length compared to the flame length of flame types 10 and 14.

As far as low N0X burners are concerned, it has been found that an internal air staggering requires the formation of a fuel-rich high-temperature pyrolysis zone near the low N0X burner outlet, followed subsequently by a poor flame region where the pyrolysis fuel products are burned by mixing with residual combustion air. With respect to radially stratified flame core burners in particular, the radial stratification extends the residence time within the fuel-rich high temperature pyrolysis zone and thus has the effect of increasing the conversion of the total bound nitrogen to N2. Moreover, it has been recognized that prompt ignition and rapid temperature rise within the pyrolysis zone with high temperature rich in fuel, are important to achieve low N0X emissions. Relating the foregoing to the types of flame 10, 12 and 14 that are schematically illustrated in Figures 1, 2 and 3 of the drawing, a type of flame having a very short flame length such as flame type 14 incorporates the following characteristics. A type of flame such as the type of flame 14 consists of a very short flame, well stirred with high volumetric heat release. Furthermore, a type of flame such as the type of flame 14 has a very high degree of turbulent flow since the air injected into the interior zone at the which will be further referred to below, and a simple strong internal recirculation zone within the aforementioned inner zone, without penetration of this simple strong internal recirculation zone by the air injected into the aforementioned inner zone, nor by the fossil fuel injected into the aforementioned inner zone. Ninety-nine percent of the burning of the fossil fuel injected into the aforementioned inner zone is able to be achieved with the type of flame 14. Of the three types of flames, that is flame types 10, 12 and 14, the type Flame 14 has the highest level of NOx emissions, because the area of high temperature pyrolysis, rich in coiribustibie is very small, that is to say it has the shortest residence time, and in this way by virtue of being very For example, the type of flame 14 is still capable of allowing N0X emissions to be reduced to a level that allows the state and federal N0X limits to be met. On the other hand, a type of flame such as the type of flame 10 having a long flame length, is characterized by the following. That is, a type of flame such as the type of flame 10, has a lower degree of turbulent flow as long as it is related to the air injected in the inner zone previously referred to with respect to the type of flame 14. Even more, a type of flame such as the type of flame 10 that has A long flame length is additionally characterized in that it incorporates two internal recirculation zones. One of these two internal recirculation zones, that is to say the first internal recirculation zone, is located on the axis of the flame that is produced by the radially stratified flame core burner and is a creation of the air that is injected into the area of the flame. above mentioned interior. In addition, this first internal recirculation zone is completely penetrated by the fossil fuel that is injected into the aforementioned inner zone. The internal recirculation zone, ie the second recirculation zone, is located downstream of the first recirculation zone and is displaced radially from the axis of the flame that is produced by the core burner with radially stratified flame. The second internal recirculation zone is a creation of the air that is injected into the outside area to which additional mention will be made below. Due to the integral penetration of the first internal recirculation zone by the fossil fuel that is injected in the aforementioned inner zone, the type of flame 10 produces a flame of low NO, but high CO and high opacity. Next, consideration will be given to a type of flame such as the type of flame 12"having an average flame length." A type of flame such as the type of flame 12 having an average flame length is also characterized by the The fact that it has a turbulent flow degree, provided that the air injected in the inner zone referred to above similar to that possessed by the type of flame 10 and a lower degree of turbulent flow than that possessed by the type of flame 14. In addition, a type of flame such as the type of flame 12, is characterized in that, like the type of flame 10, it also incorporates two internal recirculation zones, ie a first internal recirculation zone and a second recirculation zone internal The first internal recirculation zone and the second internal recirculation zone of the flame type 12, are placed between each other and with respect to the axis of the flame produced by the radially stratified flame core burner as well as the first internal recirculation zone and the second internal recirculation zone of the flame type 10, and are created in the same manner as the first internal recirculation zone and the second internal recirculation zone of the flame type 10. However, unlike the case of flame type 10 , which is the subject of previous discussion, the air that is injected into the aforementioned inner zone as well as the fossil fuel that is injected in the aforementioned inner zone, only penetrates partially into the second internal recirculation zone before the air and fossil fuel are diverted to circulate on the outer border of the second internal recirculation zone. While the type of flame 14 as previously described is characterized by the fact that the N0X emissions are reduced, at least as far as flame types 10, 12 and 14 are concerned, and while the type of flame 10 as previously described is characterized due to the fact that it produces a flame of low NO, but high CO and high opacity, the type of flame 12 achieves the optimum, that is, under N0X, low CO and low opacity. Reference will now be made to Figures 5 and 6 of the drawing for purposes of establishing here a description of the outer zone and the interior zone to which considerable prior mention has been made. For this purpose, only those components of a radially stratified flame core burner, such as the radially stratified flame core burner which is generally denoted by the reference number 22 in Figures 5 and 6 of the drawing, will be described in detail here. Reference may be made to the prior art for a description of the other components of a radially stratified flame core burner that is not described in detail here. Continuing, as is better understood with reference to Figure 6 of the drawing, the outer area to which considerable mention has been previously made, comprises the area whose diameter is denoted by the reference number 24. On the other hand, the inner zone A which considerable mention is previously made, it comprises the area whose diameter is denoted in the Figure by the reference number 26. Reference will next be made to the internal flow path of the radially stratified flame core burner 22 through which the air circulates before being injected into the outer zone 24, and of the internal flow paths of the radially stratified flame core burner 22, through which air and fossil fuel flow before being injected into the interior zone '26. For this purpose again reference will be made to both Figures 5 and 6 of the drawing. As will be understood with reference to Figure 5 of the drawing, the radially stratified flame core burner 22 is designed to be mounted in a supported relationship at a pre-established site in a wall of a fossil fuel burned furnace (not shown). For this purpose, the furnace wall «burned by fossil fuel (not shown) is provided for this purpose with a convenient opening. In accordance with the radially stratified flame core burner embodiment 22 illustrated in FIG. 5 of the drawing, it is a radially stratified flame core burner assembly 22 in relation to the burned furnace wall burned with fossil fuel in the aforementioned opening ( not shown), can be achieved by mounting means denoted in Figure 5 by the reference number 28. When so mounted on the wall of the furnace burned with fossil fuel (not shown), the portion, identified in Figure 5 by the reference number 30 of the radially stratified flame core burner 22, is projected into the opening provided for this purpose in the furnace wall burned with fossil fuel (not shown). Continuing, the air circulating through the radially stratified flame core burner 22, before being injected into the outer zone 24, enters the radially stratified flame core burner 22 through a plurality of inlet openings, denoted in Figure 5 by reference 30. For the purpose of maintaining illustration clarity in the drawing, only two of this plurality of inlet openings 30 are visible in Figure 5. After entering the radially laminated flame core burner 22 through the plurality of inlet openings 30 with which the radially stratified flame core burner 22 is provided for this purpose, the air as best understood with reference to Figure 6 of the drawing, circulates through means denoted by the reference number 32 in the Figure 6, suitable for use for purposes of imparting a predetermined angular momentum to the air before the air is injected into the area outer 24. As seen with reference to Figure 6 of the drawing, "means 30 are conveniently located at a predetermined distance inside the radially stratified flame core burner 22.

For ease of understanding, this predetermined distance is denoted in Figure 6 by the arrows that are identified in Figure 6 through use of the reference number 34. By virtue of being located inside the radially stratified flame core burner 22, the media is not susceptible to being exposed to the heat that is radiated from the furnace burned with fossil fuel (not shown). Next, description will be made of the flow paths through the radially stratified flame core burner 22 of the air and the fossil fuel that is injected into the interior zone 26. For this purpose, reference will again be made to Figures 5 and 6 of the drawing. For this purpose, the fossil fuel as best understood with reference to Figure 5 of the drawing, enters the radially stratified flame core burner 22 through the fuel inlet opening, denoted in Figure 5 with the reference number 36 After entering the radially stratified flame core burner 22 through the fuel inlet opening 36, the fossil fuel flows essentially over the center line of the radially stratified flame core burner 22 before being injected into the inner zone 26. another part, the air that is injected into the inner zone 26 circulates in relation surrounding the flow path that the fossil fuel continues to circulate through the radially stratified flame core burner. 22. For this purpose, after entering the radially stratified flame core burner 22, through suitable inlet openings with which the radially stratified flame core burner 22 is provided for this purpose, the air circulates through means, identified in FIG. Figure 6 of the drawing by reference number 38, convenient to use for the purpose of imparting an angular momentum to the air before the air is injected into the interior zone 26. As previously stated, 60 to 80% of the total of air required for the combustion of fossil fuel that is injected into the inner zone 26, is injected into the outer zone 24, while the rest of the total air required for the combustion of fossil fuel "which is injected into the indoor air 26, is injected together with the fossil fuel to the inner zone 26. Furthermore, as previously stated, according to the present invention, when controlling the moment or angular of the air that is injected into the interior zone 26 and by controlling the injection angle in which the fossil fuel is injected into the interior zone 26, it is possible to control over, that is to say cause the screen to be produced by the burner radially stratified flame core 22 as a consequence of the combustion of the fossil fuel that is injected into the inner zone 26 having a predetermined length wherein the predetermined flame length is established as a function of the depth of the furnace burned with fossil fuel where the radially stratified fame core burner 22 will be installed. Reference will now be made to Figure 7 of the drawing where a second embodiment of a radially stratified flame core burner, generally denoted, is illustrated. by the reference number 22 ', with which the method for controlling a radially stratified flame core burner of the present invention can be employed. The only major difference between the nature of the construction of the radially stratified flame core burner 22 which is illustrated in Figures 5 and 6 of the drawing and the radially laminated flame core burner 22 'which is illustrated in Figure 7 of the drawing, resides in the nature of the construction of the inlet openings through which the air that is injected into the outer zone 24 enters the radially stratified flame core burners 22 and 22 d For this purpose, in the case of the core burner of radially stratified flame 22, a transition piece denoted by the reference numeral 40 in Figure 5 of the drawing, is interposed between the inlet opening 30 and the interior of the radially stratified flame core burner 22. On the other hand, in the case of the radially stratified flame core burner 22 the transition piece 40 associated with each of the inlet openings 30 in the case of the radially stratified flame core burner 22 has been removed such that in the case of the radially stratified flame core burner 22 ', the air that is injected into the outer zone 26 after entry to the radially laminated flame core burner 22' through the inlet openings 30, it flows directly from there into the radially stratified flame core burner 22 '. Thus, in accordance with the present invention, a new and improved method for controlling a radially stratified flame core burner is provided. Likewise, this new and improved method for controlling a radially stratified flame core burner is provided in accordance with the present invention, so that regardless of the depth that a furnace may incorporate, the radially stratified flame core burner still Will it be effective to allow the desired reduction to be achieved? NOx emissions. Still further, in accordance with the present invention, this new and improved method is provided for effecting control over a radially stratified flame core burner wherein the radially stratified flame core burner is still capable, without the use of recirculation of flue gas or secondary air, to reduce N0X emissions to a level that allows compliance with the state limits and. of N0X. Also, it is provided in accordance with the present invention, this new and improved method to control a radially stratified flame core burner that is capable of achieving N0X values of less than 0.448 kg / MM kilocalories (0.25 Ib. / MM BTU) while combustion fuel No. 6 is burned. Also, according to the present invention, this new and improved method for controlling a radially stratified flame core burner incorporating the ability to adjust its angular momentum and derive the air flow is provided. In addition, this new and improved method for effecting control in a radially stratified flame core burner is characterized in that the operating mechanisms are placed to protect against heat radiated from the furnace. Further, there is provided in accordance with the present invention, this new and improved method for effecting control over a radially stratified flame core burner wherein the radially stratified core burner has capabilities for multiple fuels, ie oil, natural gas and mineral coal. Further, in accordance with the present invention, this new and improved method is provided for effecting control over a radially stratified flame core burner, wherein the radially stratified flame core burner is capable of being integrated "into virtually any new or existing systems. burned by combustion.In addition, it is provided in accordance with this invention, this new and improved method for effecting control over a radially stratified flame core burner, wherein the radially stratified flame core burner is capable of being modified in series production in virtually any boiler design. In penultimate place, according to the present invention, this new and improved method for controlling a radially stratified flame core burner is provided, wherein the radially stratified flame core burner has a nominal burner heat supply rate from .253 MM kilocalories per hour (1 MM BTU per hour). Finally, there is provided in accordance with the present invention, this new and improved method for effecting control over a radially stratified flame core burner, wherein the radially stratified flame core burner allows high grade materials to be selected for use in order to This way attend the aspects of heat and / or corrosion. While a modality of our invention has been shown, it will be appreciated that its modifications, some of which have been alluded to hereinbefore, can still be easily accomplished by "those with skill in the specialty. Therefore, we intend that the appended claims cover the aforementioned modifications as well as all other modifications that fall within the spirit and real scope of our invention.

Claims (10)

1. CLAIMS 1. A method for effecting control over a radially stratified flame core burner of the type installed in a furnace burned with fossil fuel, characterized in that it comprises the steps of: a) determining the depth of the furnace in which the core burner is installed. radially stratified flame; b) establish the permissible length of the flame that. the radially stratified flame core burner is capable of producing as a function of the furnace depth burned with fossil fuel where the radially stratified furnace is installed; c) establishing an outer air flow zone as a consequence of the injection of a first portion of the total amount of air required to effect combustion of the fossil fuel that is burned through operation of the radially stratified flame core burner; d) establishing an internal zone of air flow and fossil fuel as a consequence of the injection of a second portion of the total amount of air required to effect the combustion of the fossil fuel that is burned through the operation of the radially stratified flame core burner and as a consequence of the injection of the fossil fuel that is burned through the operation of the radially stratified flame core burner; and control the length of the flame produced by the radially stratified flame core burner, by controlling the angular momentum of the air injected into the interior zone and controlling the injection angle of the injected fossil fuel to the interior zone in such a way that the length of the flame produced by the radially stratified flame core burner is not greater than the permissible length of the the flame that has been established by the furnace burned with fossil fuel, where the radially stratified flame core burner is installed.
2. 2. The method for effecting control over a radially stratified flame core burner as described in claim 1, characterized in that the first portion of the total air injected into the outer zone comprises 60 to 80% of the total amount of air required to effect the combustion of fossil fuel that is burned through the operation of the radially stratified flame core burner.
3. 3. The method for controlling a radially stratified flame core burner as described in claim 2, characterized in that it further comprises the step of imparting an angular moment to the first portion of the total air injected into the outer zone before it is injected. the first portion of the total air.
4. 4. The method for effecting control over a radially stratified flame core burner as described in claim 3, characterized in that the outer air flow area is coaxial but spaced from the central line of the radially stratified flame core burner.
5. 5. The method for effecting control over a radially stratified flame core burner as described in claim 2, characterized in that the second portion of the total air injected into the interior zone comprises the remainder of the total air required to effect combustion of the fossil fuel. it is burned through the operation of the radially stratified flame core burner.
6. 6. The method for effecting control over a radially stratified flame core burner as described in claim 5, characterized in that the inner air flow area and the fossil fuel are located on the center line of the radially stratified flame core burner.
7. 7. The method for effecting control over a radially stratified flame core burner as described in claim 6, characterized in that it further comprises the step of imparting an angular momentum to the second portion of the total air that is injected into the inner zone before that the second portion of the total air is injected.
8. 8. The method for effecting control over a radially stratified flame core burner as described in claim 1, characterized in that all the fuel Fossil is burned through operation of the radially stratified flame core burner is injected to the inner zone.
9. 9. The method for effecting control over a radially stratified flame core burner as described in claim 8, characterized in that the fossil fuel is injected into the inner zone on the center line of the radially stratified flame core burner.
10. 10. The method according to claim 1, characterized in that the radially stratified flame core burner has a nominal thermal feed rate to the burner from .253MM kilocalories (1MM BTU). SUMMARY OF THE INVENTION A method for effecting control over a radially stratified flame core burner (22) of the type installed in a furnace burned with fossil fuel, comprising the steps of: a) determining the depth of the furnace where the core burner radially stratified flame is installed; b) establishing the permissible length of the flame that the radially stratified flame core burner is capable of producing, as a function of the depth of the furnace burned with fossil fuel in which the radially stratified furnace is installed; c) establishing an outer air flow zone (24) as a consequence of the injection of a first portion of the total amount of air required to effect combustion of the burned fossil fuel through operation of the radially stratified flame core burner; d) establishing an interior zone (26) of air flow and fossil fuel as a consequence of the injection of a second portion of the total amount of air required to effect combustion of the fossil fuel that is burned through the operation of the core burner. radially stratified flame and as a consequence of the injection of fossil fuel that is burned through the operation of the radially stratified flame core burner and e) control the length of the flame produced by the radially stratified flame core burner and controlling the angular momentum of the air injected into the interior zone and controlling the injection angle of the injected fossil fuel to the lower zone such that the length of the flame produced by the radially stratified flame core burner is not greater than the permissible length from the flame that has been established with the furnace burned with fossil fuel where the radially stratified flame core burner is installed.