Apparatus method for natural gas enrichment of a combustion apparatus

Abstract

An apparatus (10) for combusting pulverized fuel is provided that includes a combustion chamber. Air containing the fuel enters the combustion chamber (20) though a first conduit at a first inlet. A second conduit (30) upstream of the combustion chamber is configured to introduce gaseous fuel at an ignition means. The gaseous fuel is combined wit the ais containing the pulverized fuel upstream of the combustion chamber for good ignition and turn down capability.

Description

701001-WO-1 (GTV1020-0445WO) METHOD FOR NATURAL GAS ENRICHMENT OF A COMBUSTION APPARATUS BACKGROUND TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate generally to a combustion system and improvements thereof, more particularly a combustion system for a boiler for power generation having fuel stream distribution means in a burner. The improvements are directed to improving efficiency and reducing emissions. DISCUSSION OF ART

[0002] The present invention relates to a combustion apparatus, for example a coal combustion apparatus, capable of improving combustion efficiency and saving energy by supply and combusting combustion gas to coal.

[0003] Coal and oil-fired boilers are used to generate steam for many industrial purposes, for example to drive electric generating, steam powered turbines for the electric utility industry. The coal or oil occur in a condensed solid or liquid state and must be ground or pulverized, in the case of coal, or atomized, in the case of oil, before being able to be combusted efficiently in the furnace section of the boiler. Either of these finely ground or atomized fuels must then be heated to an extent to volatize a portion of the fuel into the gaseous phase before mixing with air and combustion begins.701001-WO-1 (GTV1020-0445WO)

[0004] Natural gas occurs in the gaseous state and is easier to ignite and burn since there are no preparation or volatilization steps. Once ignited, the gas burns as it mixes with air, within its combustion limits of sufficient air but not too much air.

[0005] Boilers often have combustion systems with furnaces that may be fired with solid fuel, such as coal. Lignite, biomass, or the like. Such combustion systems are typically provided with mills arranged to pulverize the solid fuel and ducting for supplying the pulverized fuel to one or more burners. The pulverized coal and air is supplied into a combustion chamber of the boiler and ignited to create hot flue gases which can be used to create steam for power generation or other application.

[0006] Instead of pulverized fuels, other fuel types, such as gaseous fuels may be used from combustion in a boiler. It is desired to also use fuel gas mixtures obtained from finery gases, for example. Refinery gases are gaseous by-products in petroleum refineries, which are produced during the processing of crude oil. Refinery gases may have low calorific value and may be mixed with natural gas and / or gaseous liquefied petroleum gas (LPG) and fed to a furnace.

[0007] During the combustion process of fossil fuels pollutants, such as nitrogen oxides (NOx), particulate matter (PM), and carbon monoxide (CO), are generated. If exhausted into the atmosphere, these pollutants can pose health hazards to humans and animals and detrimentally impact the environment. Emission standards throughout the world, including EU and US, regulate acceptable emission limits for NOx, CO, and other pollutants. But there is still a need to further reduce the actual emission levels.

[0008] NOx emissions may be reduced by lowering the flame temperature, but reducing the flame temperature may decrease the radiant heat transfer from the flame and thus lower the701001-WO-1 (GTV1020-0445WO) boiler efficiency. Some NOx control technologies used on boilers reduce NOx levels by lowering flame temperatures by modifying air / fuel mixing patterns. The lower flame temperatures and decreased mixing intensities can result in higher CO levels. High flame temperatures, intimate air / fuel mixing and a nearly complete burnout of the fuel are essential for low CO emissions. High levels of CO emissions primarily result from incomplete combustion due to poor burner design or firing condition, for example, an improper air-to-fuel ratio.

[0009] Other issues may arise due to the operating conditions. For example, in a pulverized coal-fired burner the pulverizing mill typically operates with a fairly constant air / gas volume flow over the whole load range. At low load, the air-fuel ratio consequently decreases, and the pulverized coal air / gas mixture becomes lean and difficult to ignite. In addition, it may be difficult to adequately stabilize the flame, causing the flame to blow out or blow back. This may be aggravated by a poor quality and / or distribution pattern of the fuel supplied to the combustion chamber of the boiler.

[0010] It is an object of the present invention to remove or reduce the deficiencies of the prior art combustion systems and methods. In particular, it is an object of the present invention to provide a combustion system which can increase efficiency and low load stability, as well as reduce emissions. BRIEF DESCRIPTION

[0011] Certain embodiments commensurate in scope with the originally claimed subject matter are summarized below. These embodiments are not intended to limit the scope of the claimed subject matter, but rather these embodiments are intended only to provide a brief summary of the possible embodiments. Indeed, the disclosure may encompass a variety of forms that may be similar to or different from the embodiments set forth below.701001-WO-1 (GTV1020-0445WO)

[0012] The present invention relates to gas enrichment for coal fired steam generation units. The system can be easily adapted to existing units. The gas enrichment improves low load stability of the system and reduces emissions. The gas enrichment may address both with a flexible, low-cost solution. A small amount of gas, for example natural gas, maybe used to enhance the volatile material (VM) of the fuel mixture. Enhancing the VM content stabilizes the existing coal stream ignition point, which improves turndown capability and reduces emissions. The gas may be injected into a secondary air stream outside a primary stream, where the primary stream includes the primary fuel source, for example coal. The secondary air stream may be introduced adjacent to or parallel with the primary stream to improve and stability the ignition point.

[0013] When the gas is introduced via the secondary air stream, the natural gas and the primary stream may mix via diffusion mixing. This may stabilize the ignition point closer to the coal compartment assembly.

[0014] According to an aspect of the invention, an apparatus for combusting fuel is provided. The apparatus includes a combustion chamber, an ignition means, and one or more secondary conduits. The combustion chamber includes a first inlet in communication with a first fluid stream containing a first fuel source. The ignition means is in fluid communication with the combustion chamber and the first fluid stream. The secondary conduits are upstream of the combustion chamber and are configured to introduce one or more second fluid streams containing an additive component at the ignition means. The second fluid streams are configured to combine with the first fluid stream upstream of the combustion chamber.

[0015] In one embodiment, a system for combusting a fuel source is provided. The apparatus includes a combustion chamber, an ignition point, a first conduit, and one or more701001-WO-1 (GTV1020-0445WO) secondary conduits. The combustion chamber includes a first inlet. The first conduit is configured to transport a fuel source through the first inlet. The ignition point is positioned upstream of the first inlet and configured to ignite the fuel source. The secondary conduits are upstream of the first inlet. The secondary conduits are configured to introduce one or more second fluid streams at the ignition point. The second fluid streams are configured to combine with the first fluid stream.

[0016] In one embodiment, a method for improving combustion of a fuel source is provided. The method includes directing a primary fuel stream into a combustion chamber and igniting the primary fuel stream using an ignition point upstream of the combustion chamber. The method includes stabilizing the ignition point by directing a secondary stream to the ignition point to combine the secondary stream with the primary fuel stream. BRIEF DESCRIPTION OF THE FIGURES

[0017] The present invention will be better understood from reading the following description of non-limiting embodiments, with reference to the attached drawings, wherein below:

[0018] Fig.1 is a cross-sectional view of a portion of a combustion apparatus, according to one example.

[0019] Fig.2 is a cross-sectional view of a portion of a combustion apparatus, according to one example.

[0020] Fig.3a is a perspective view of a portion of a combustion apparatus including a coal compartment, according to one example.

[0021] Fig.3b is a top view of a portion of a combustion apparatus including a coal compartment with gas injection locations, according to one example.701001-WO-1 (GTV1020-0445WO)

[0022] Fig.4 is a top view of a portion of a combustion apparatus including a coal compartment and a secondary conduit, according to one example.

[0023] Fig.5a is a secondary conduit of a combustion apparatus, according to one example.

[0024] Fig.5b is a secondary conduit of a combustion apparatus, according to another example.

[0025] Fig.6 is a secondary conduit of a combustion apparatus, shown distributing a fluid, according to one example. DETAILED DESCRIPTION

[0026] Reference will be made below in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference characters used throughout the drawings refer to the same or like parts.

[0027] As used herein, the terms “approximately” and “about,” as applied to one or more values of interest, refer to a value that is similar to a stated reference value. In some embodiments, the term “approximately” or “about” refers to a range of values that fall within, for example, 25%, 20%, 10%, 5%, 4%, 3%, 2%, 1%, or less in either direction (greater than or less than) of the stated reference value unless otherwise stated or otherwise evident from the context (except where such number would exceed 100% of a possible value).

[0028] A small quantity of an additive material, for example a natural gas, may be introduced at an ignition point. The introduction of the additive material improves flame stability, which results in extended turndown range. Additionally, the small quantity of the additive material results in a significant reduction in emissions, for example NOx, sulfur oxides (SOx), or CO emissions. By generating products of combustion readily available for diffusion701001-WO-1 (GTV1020-0445WO) mixing directly into the ignition point / flame root, the system may effectively dilute or reduce the available oxygen present at the flame, which results in lower NOx emissions.

[0029] The addition of the additive material may be applicable for any transverse fired boiler arrangement or coal compartment assembly for coal fired steam generators. Addition of a small natural gas port lance(s) may be made at each coal compartment assembly along with associated natural gas valve train at each compartment assembly for local natural gas control.

[0030] The present subject matter is advantageous because there is a minimal impact to the design of the existing system and allows a flexibility in operation. No additional ignitors are required and no changes are required to existing flame scanners.

[0031] Fig.1 illustrates a cross-section view of a portion of a combustion apparatus, according to one embodiment. The combustion apparatus 10 may be provided in a conventional heating or steam boiler or a thermal power generator. The combustion apparatus 10 includes a fuel supply means for supplying a fuel 14. Combustion systems for boilers may use a variety of different types and qualities of fuels, including pulverized fuels, such as coal, petroleum coke, bituminous coal, lignite, biomass, etc., and a broad range of mixed gas fuels, such as refinery and other waste gases, while assuring safe ignition and combustion of the fuel, adequate stabilization of the flame and highly efficient performance with reduced NOx and CO emissions over the entire operating range, for full and part-load operations. As discussed further below, a second fluid stream including an additive material may be added to improve stabilization and efficiency, while reducing emissions. The fuel supply means may include a hopper 16 or another container.

[0032] The fuel 14 is conveyed and injected along a first fluid stream 22, through a fuel nozzle 25, and into a combustion chamber 20. The first fluid stream 22 may include the fuel and an air stream. As illustrated in Fig.1, there may be more than one first fluid stream 22 in the701001-WO-1 (GTV1020-0445WO) combustion apparatus 10. The first fluid streams may be positioned parallel to each other, or at an angle relative to each other.

[0033] The combustion chamber 20 may include an inlet 24 in fluid communication with the fuel nozzle 25 and the first fluid stream 22. The fuel 14 is typically conveyed in a stream of primary air into the combustion apparatus via one or more inlets 24.

[0034] Prior to entering the combustion chamber 20, the fuel 14 of the first fluid stream 22 is provided to an ignition means 26. In one example, the ignition means 26 is positioned adjacent the fuel nozzle 25. The ignition means 26 is in fluid communication with the combustion chamber 20 and the first fluid stream 22. The ignition means 26 ignites and combusts the fuel 14 provided by the first fluid stream 22. The ignition means 26 includes an igniter 28. The igniter 28 ignites the fuel 14 and creates combustion.

[0035] The combustion apparatus 10 further includes one or more secondary conduits 30 upstream of the combustion chamber 20. The secondary conduits are configured to carry a fluid stream containing an additive material and an air stream. The secondary conduits 30 are configured to introduce one or more second fluid streams 32 via an air outlet 27 at the ignition means 26. The second fluid streams 32 include the additive component or material, for example natural gas, propane, butane, liquefied petroleum gas (LPG), a volatile hydrocarbon, or the like.

[0036] The second fluid streams 32 are configured to combine with the first fluid stream 22 upstream of the combustion chamber 20. The second fluid streams 32 including the additive material are added to the first fluid stream 22 including the fuel 14 in order to increase the volatile material (VM) of the fuel to stabilize the coal stream ignition point and improve the turndown limits. Turndown of a combustion apparatus or boiler is a ratio between the apparatus’ maximum and minimum output. The turndown is improved by allowing the apparatus to function701001-WO-1 (GTV1020-0445WO) at lower load outputs, thus increasing the functionality of the apparatus by operating with less energy expended. Further, the addition of the additive material to the fuel reduces emissions in both low load and high load outputs. The emissions are reduced because the additive material mixed with the fuel creates a product that is more combustion ready at the flame root than the fuel alone. This mixture effectively dilutes and reduces the available O2present at the flame, resulting in lower emissions, for example NOx emissions.

[0037] In one embodiment, the second fluid streams 32 combines with the first fluid stream via diffusion mixing. The second fluid stream 32 may contain a minimal volume relative to the first fluid stream, for example 10% or less of a volume of the first fluid stream, more specifically 2% or less of a volume of the first fluid stream.

[0038] The secondary conduits 30 may be movable. For example, the secondary conduits 30 may include a tilt drive component 31. The tilt drive component allows the secondary conduits 30 to move relative to the first fluid stream 22 and / or the ignition means 26. In one example, the entire secondary conduit 30 is moved by the tilt drive component 31, however, in other embodiments only a portion of the secondary conduit 30, for example the air outlet 27 is moveable by the tilt drive component 31. Moving the secondary conduits may allow for more customizable flow of the second fluid streams to adjust the mixing, based on desired mixing characteristics. Further, adjusting the flow rate, velocity, pattern, point of injection relative to the igniter may be important factors in customizing the mixing of the second fluid streams. As further discussed below, outlets of the secondary conduits may be adjusted or modified based on a desired spray pattern or mixing characteristic.

[0039] The additive material is introduced at the ignition point or igniter 28 to enrich the fuel stream to increase the VM content of the fuel stream. The additive material stabilizes the701001-WO-1 (GTV1020-0445WO) fuel stream at the igniter 28, which results in improved existing turndown limits of the combustion apparatus. The additive material further improves flame stability.

[0040] The additive material additionally results in significant reductions in emissions at all loads by generating products of combustion readily available for diffusion mixing directly into the flame root.

[0041] In an embodiment, the secondary conduits may be a small port or lance added at or adjacent to each fuel compartment assembly. This allows for introduction of the additive material at each fuel compartment. In other examples, there may be a different number of ports or lances per fuel compartment assembly, for example one port or lance for every two fuel compartment assemblies. Additionally, a valve may be added at each compartment to allow for local control of the additive material. The valve may be a flow rate control valve configured to modify a flow rate of the second fluid streams. The valve may be manually controlled, electrically controlled, autonomously controlled, or the like.

[0042] The combustion apparatus may include a controller that may control the flow of the first fluid stream, the flow of the second fluid streams, the valve, or another component of the apparatus. The controller may include microcontrollers, processors, microprocessors, or other logic devices that operate based on instructions stored on a tangible and non-transitory computer readable storage medium, such as software applications stored on a memory.

[0043] Introducing the additive material directly into the first fluid stream directly or into a mixing chamber along with the first fluid stream, did not produce improved stability and reduction of emission. However, introducing the additive material to the second fluid streams and introducing the second fluid streams at the ignition means was found to significantly improve and stabilize the ignition point. Introduction of the streams at the ignition means results701001-WO-1 (GTV1020-0445WO) in effective diffusion mixing of the additive material and associated products of combustion directly into the fuel stream at the ignition means. In one example, the second fluid streams are adjacent to or parallel with the first fluid stream.

[0044] This arrangement can be implemented on existing coal fired steam generation units with minimal impact to the design. Besides the additional secondary conduits, no additional components are needed. As such, this improvement is cost and labor effective. This system allows the units to operate at lower loads without support fuels for extended periods of time. This reduces the cost of support fuel, as well as reduces the maintenance costs for support fuel systems. Further, with the improved flame stability provided by the secondary conduits, the system can operate at lower loads, as low as 10% maximum continuous rating (MCR) for units without selective catalytic reduction (SCR), and 25% to 30% for units with SCR’s and no gas by-pass system. The MCR is the maximum output which the combustion apparatus or boiler can deliver when operated at a specified set of conditions. MCR can also be understood to be the minimum assured production of steam in a boiler. The enrichment with the second fluid steams may also support up to a 6% reduction in NOxemissions at boiler maximum continuous rating (BMCR). The BMCR is the maximum steam output the steam boiler can deliver continuously at rated parameters. Larger emission reductions are possible at lower loads.

[0045] Fig.2 illustrates a cross-sectional view of a combustion apparatus according to an embodiment. The combustion apparatus includes a coal compartment 21 with gas injection locations 52. The coal compartment 21 runs along the first fluid stream 22 and ends at the fuel nozzle 25. As shown, the coal compartment may include an elbow joint 50. In other embodiments, the coal compartment may be straight and may not have an elbow joint, or may have a different shape or orientation. The second fluid stream 32 is configured to dispense an701001-WO-1 (GTV1020-0445WO) additive material, for example a natural gas, to mix with the first fluid stream. As illustrated, the natural gas may be injected at one or more locations 52. In one example, gas is injected at the elbow 50 and at the fuel nozzle 52.

[0046] Fig.3a illustrates a perspective view of a combustion apparatus including a coal compartment 21, according to an embodiment. The system includes a secondary conduit 30 or side lance that runs adjacent to the coal compartment 21. The secondary conduit may run parallel to the coal compartment. In one embodiment, there are one or more secondary conduits. For example, there may be a left side secondary conduit on the left side of the coal compartment and a right side secondary conduit on the right side of the coal compartment, as shown and describe further with respect to Fig.3b. In another example, there may be a top side secondary conduit and a bottom side secondary conduit.

[0047] Fig.3b illustrates a top view of a combustion apparatus fuel including a coal compartment 21 with gas injection locations, according to an embodiment. The system includes secondary conduits 30 running adjacent to the coal compartment 21. The coal compartment includes a first fluid stream 22, as described above, carrying a first fluid flow, for example a fuel and an air stream. The secondary conduits include a second fluid stream 32, as described above, for example natural gas. In one example, the secondary conduits run substantially parallel to the coal compartment. The secondary conduits 30 are configured to extend to an air nozzle 27 that is adjacent to the fuel nozzle 25 of the coal compartment. The air nozzle 27 and the fuel nozzle 25 are positioned to be adjacent an ignition point. The contents exiting the air nozzle 27 (e.g., natural gas) are configured to combine with the contents exiting the fuel nozzle 25 (e.g., fuel and the air stream) via diffusion mixing.701001-WO-1 (GTV1020-0445WO)

[0048] Fig.4 depicts a top view of a combustion apparatus including a coal compartment 21 with a secondary conduit 30 including a second fluid stream 32. While shown with one second fluid stream, it is understood that in other embodiments, the system may include more than one second fluid streams. In embodiments with multiple second fluid streams, the second fluid streams may be equally spaced around the coal compartment or may be spaced with varying distances spacing the second fluid streams around the coal compartment.

[0049] Referring now to Fig.5a, a secondary conduit 30 of a combustion apparatus, according to an embodiment, is illustrated. Fig.5b illustrates a secondary conduit 30 according to another embodiment. The embodiment shown in Fig.5a includes an outlet 60 at a distal end of the secondary conduit 30. The additive material, for example natural gas, exits the outlet 60. The embodiment shown in Fig.5b includes one or more outlets 61. The outlets 61 may be spaced around a cylindrical portion of the secondary conduit 30. The outlets 61 facilitate a greater spray pattern than the outlet illustrated in Fig.5a. In some examples, the greater spray pattern may result in greater mixing of the natural gas with the first fluid stream. The size of the outlets 61 may be modified based on desired output and distribution of the natural gas. While the outlets 61 are shown as being generally linear, the outlets may be different shapes in other embodiments. For example, the outlets may have a spiral shape, a zig-zag shape, or the like.

[0050] Fig.6 illustrates the secondary conduit 30 and outlets 61 shown in Fig.5b, where the outlets 61 are dispensing a liquid. This figure is illustrative of a potential spray pattern of the outlets 61. As discussed, in embodiments, the number, shape, size, and orientation of the outlets may be modified based on desired mixing characteristics.701001-WO-1 (GTV1020-0445WO)

[0051] In one embodiment, the secondary conduit 30 may include an outlet at the distal end, as shown in Fig.5a, as well as outlets spaced around the cylindrical portion of the secondary conduit, as shown in Fig.5b.

[0052] In one embodiment, an apparatus for combusting fuel is provided. The apparatus includes a combustion chamber, an ignition means, and one or more secondary conduits. The combustion chamber includes a first inlet in communication with a first fluid stream containing a first fuel source. The ignition means is in fluid communication with the combustion chamber and the first fluid stream. The secondary conduits are upstream of the combustion chamber and are configured to introduce one or more second fluid streams containing an additive component at the ignition means. The second fluid streams are configured to combine with the first fluid stream upstream of the combustion chamber.

[0053] In one example, the fuel source includes one or more of coal, biomaterials, or petroleum coke. The one or more second fluid streams are movable, for example pivotable. The second fluid streams are configured to increase a turndown ratio of the apparatus. A volume of the one or more second fluid streams is 2% or less of a volume of the first fluid stream. The second fluid streams may run parallel to the first fluid stream. The one or more second fluid streams are configured to combine with the first fluid stream via diffusion mixing.

[0054] The one or more secondary conduits may be in fluid communication with a flow rate control valve configured to modify a flow rate of the one or more second fluid streams. The additive component may include one or more of propane, butane, natural gas, liquefied petroleum gas (LPH), or a volatile hydrocarbon. In one example, at least one of the one or more secondary conduits are located at a coal compartment of a transverse boiler.701001-WO-1 (GTV1020-0445WO)

[0055] In an embodiment, a system for combusting a fuel source is provided. The apparatus includes a combustion chamber, an ignition point, a first conduit, and one or more secondary conduits. The combustion chamber includes a first inlet. The first conduit is configured to transport a fuel source through the first inlet. The ignition point is positioned upstream of the first inlet and configured to ignite the fuel source. The secondary conduits are upstream of the first inlet. The secondary conduits are configured to introduce one or more second fluid streams at the ignition point. The second fluid streams are configured to combine with the first fluid stream.

[0056] In one example, each of the one or more secondary conduits includes one or more outlets for egress of the second fluid streams. The one or more second fluid streams are movable, for example pivotable. The one or more second fluid streams are configured to increase a turndown ratio of the system. A volume of the one or more second fluid streams is 2% or less of a volume of the first fluid stream. The one or more second fluid streams are configured to run parallel to the first fluid stream. The one or more second fluid streams may be configured to combine with the first fluid stream via diffusion mixing. In one example, at least one of the one or more secondary conduits are located at a coal compartment of a transverse boiler.

[0057] In one embodiment, a method is provided for producing a composition that includes a nanoparticle with at least one nucleic acid and at least one ionizable lipid, the method may include the steps of: introducing a first composition that includes the at least one nucleic acid and a second composition that includes the at least one ionizable lipid into at least one reactor, filtering the nanoparticle from the reaction mixture via a single-pass tangential flow filter, and filtering retentate through a sterile filtration membrane to produce the composition.701001-WO-1 (GTV1020-0445WO)

[0058] In one example, at least a portion of the primary fuel stream and the secondary stream are parallel.

[0059] It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and / or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the inventive subject matter without departing from its scope. While the embodiments described herein are intended to define the parameters of the inventive subject matter, they are by no means limiting and are example embodiments. Many other embodiments will be apparent to one of ordinary skill in the art upon reviewing the above description. The scope of the inventive subject matter should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112(f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.

[0060] This written description uses examples to disclose several embodiments of the inventive subject matter, including the best mode, and also to enable one of ordinary skill in the art to practice the embodiments of inventive subject matter, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the inventive subject matter is defined by the claims, and may include other examples that occur to701001-WO-1 (GTV1020-0445WO) one of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

[0061] As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural of said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising,” “comprises,” “including,” “includes,” “having,” or “has” an element or a plurality of elements having a particular property may include additional such elements not having that property.

[0062] This written description uses examples to disclose several embodiments of the invention, including the best mode, and also to enable one of ordinary skill in the art to practice the embodiments of invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to one of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

701001-WO-1 (GTV1020-0445WO) CLAIMS:

1. An apparatus for combusting fuel, the apparatus comprising: a combustion chamber, the combustion chamber having a first inlet in communication with a first fluid stream containing a fuel source; an ignition means in fluid communication with the combustion chamber and the first fluid stream; and one or more secondary conduits upstream of the combustion chamber, the one or more secondary conduits configured to introduce one or more second fluid streams containing an additive component at the ignition means, wherein the one or more second fluid streams are configured to combine with the first fluid stream upstream of the combustion chamber.

2. The apparatus of claim 1, wherein the fuel source includes one or more of coal, biomaterials, or petroleum coke.

3. The apparatus of claim 1, wherein the one or more second fluid streams are movable.

4. The apparatus of claim 1, wherein the one or more second fluid streams are configured to increase a turndown ratio of the apparatus.

5. The apparatus of claim 1, wherein a volume of the one or more second fluid streams is 2% or less of a volume of the first fluid stream.

6. The apparatus of claim 1, wherein the one or more second fluid streams are configured to run parallel to the first fluid stream.

7. The apparatus of claim 1, wherein the one or more second fluid streams are configured to combine with the first fluid stream via diffusion mixing.701001-WO-1 (GTV1020-0445WO) 8. The apparatus of claim 1, wherein the one or more secondary conduits are in fluid communication with a flow rate control valve configured to modify a flow rate of the one or more second fluid streams.

9. The apparatus of claim 1, wherein the additive component includes one or more of propane, butane, natural gas, liquefied petroleum gas (LPG), or a volatile hydrocarbon.

10. The apparatus of claim 1, wherein at least one of the one or more secondary conduits are located at a coal compartment of a transverse boiler.

11. The apparatus of claim 1, wherein the one or more second fluid streams include an air stream and the additive component.

12. The apparatus of claim 1, wherein the first fluid stream includes an air stream and the fuel source.

13. A system for combustion of a fuel source comprising: a combustion chamber, the combustion chamber having a first inlet; a first conduit configured to transport a first fluid stream including a fuel source through the first inlet; an ignition point positioned upstream of the first inlet and configured to ignite the fuel source; and one or more secondary conduits upstream of the first inlet, the one or more secondary conduits configured to introduce one or more second fluid streams at the ignition point, the one or more second fluid streams configured to combine with the first fluid stream.701001-WO-1 (GTV1020-0445WO) 14. The system of claim 13, wherein each of the one or more secondary conduits includes one or more outlets for egress of the one or more second fluid streams.

15. The system of claim 13, wherein the one or more second fluid streams are movable.

16. The system of claim 13, wherein the one or more second fluid streams are configured to increase a turndown ratio of the system.

17. The system of claim 13, wherein a volume of the one or more second fluid streams is 2% or less of a volume of the first fluid stream.

18. The system of claim 13, wherein the one or more second fluid streams are configured to run parallel to the first fluid stream.

19. The system of claim 13, wherein the one or more second fluid streams are configured to combine with the first fluid stream via diffusion mixing.

20. The system of claim 13, wherein at least one of the one or more secondary conduits are located at a coal compartment of a transverse boiler.

21. A method for improving combustion of a fuel source comprising: directing a primary fuel stream into a combustion chamber; igniting the primary fuel stream using an ignition point upstream of the combustion chamber; and stabilizing the ignition point by directing a secondary stream to the ignition point to combine the secondary stream with the primary fuel stream.

22. The method of claim 21, wherein at least a portion of the primary fuel stream and the secondary stream are parallel.

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