Apparatus and method for oxidant formation

Abstract

An apparatus and method for oxidant formation can be configured to facilitate improved mixing for forming oxidant. Embodiments can be configured such that a conduit having a relatively large aspect ratio (e.g., 1.5 to 5 or 1.5 to more than 5) can be used to improve gas mixing, even in cases where the carrier gas is at a relatively low pressure. Embodiments can also facilitate low nitrogen oxides formation combustion. Some embodiments can additionally provide improved carbon capture.

Description

[0001] Cross-references to related applications This application claims priority to U.S. Nonprovisional Patent Application No. 18 / 498,564, filed October 31, 2023, and U.S. Provisional Patent Application No. 63 / 527,810, filed July 19, 2023. Technical Field

[0002] This invention relates to methods and apparatus for forming an oxidant to be fed into a combustion apparatus to promote the combustion of fuel. For example, some embodiments may be configured to form and use synthetic air or oxygen-enriched air as an oxidant for the combustion of fuel. Background Technology

[0003] Combustion processes can be used in a variety of industrial environments. For example, combustion processes can be used for electricity generation, gasification, steam / hydrocarbon reforming, furnace operation to heat or melt materials, boiler operation, or power generation. Examples of combustion processes and examples of fuel and oxidant streams that can be used in combustion processes are disclosed in U.S. Patent Nos. 11,592,178, 8,808,425, 8,715,617, 8,496,908, 7,850,763, 7,303,388, and 4,495,874, and Chinese Patent Application Publication No. CN 110220378. Summary of the Invention

[0004] Rectangular duct geometry can be a challenging conduit size for gas mixing. We have found this to be especially true for conduits with relatively large dimensions (e.g., aspect ratios of 1.5 to 5 or greater than or equal to 3) where a relatively low-pressure carrier gas is present (e.g., a low-pressure carrier gas to be mixed with another gas injected into the carrier gas, where the carrier gas pressure is between 5 inches and 50 inches of water column, or between 1.2442 kPa and 12.442 kPa).

[0005] The aspect ratio of a catheter is the ratio of its height to its width (e.g., a catheter aspect ratio of 4 is a dimension in which the width of the catheter is 4 times greater than the height of the catheter. For example, a catheter with a height of 1 meter and a width of 4 meters has a catheter aspect ratio of 4, etc.).

[0006] This challenge can be exacerbated by common situations, such as when these types of pre-sized conduits may have only a relatively short length for supplying the mixed gas to form the gas fed into the combustion unit as an oxidant. In many cases, only a small section of the conduit may be available for mixing the gas, which can be supplied to form the desired oxidant-gas mixture.

[0007] Furthermore, the ratio of the fluid to be injected into another fluid for mixing to form an oxidant can make good mixing more difficult. For example, when the ratio of the injected fluid's mass flow rate to the carrier fluid's mass flow rate is between 0.1 and 1, the short length and large aspect ratio of the conduit can make it difficult to achieve good mixing. This may be especially true for rectangular conduits.

[0008] We have surprisingly discovered that a novel oxidant mixing device can be provided to promote the formation of oxidant for use in a combustion device, thereby promoting combustion within the combustion chamber of the device. The mixing device can be configured to provide a good mix of oxygen to be injected into the carrier stream. In some embodiments, the carrier stream can be air, flue gas, or a mixture of flue gas and air. Embodiments can be configured to support a wide range of injection fluid to carrier fluid mass flow rates for the formation of the desired oxidant, and such mixing for oxidant formation can be provided over a relatively short conduit length. Furthermore, some embodiments can promote improved mixing that prevents the formation of side portions of the oxidant with a higher oxygen concentration than the central region of the flow. This can help protect the conduit sidewalls and provide improved operation and performance, and can also help improve the lifespan or degradation experienced by the conduit through which the formed oxidant passes.

[0009] We have also found that implementations of our hybrid unit can help provide improved combustion processing for industrial combustion heating applications and other combustion applications that can provide reduced nitrogen oxide formation. Some implementations can also be used to help improve carbon capture, thus providing a significant reduction in carbon dioxide emissions.

[0010] For example, industrial combustion heaters can emit large amounts of nitrogen oxides (also known as NO). x (NOx or NOx). Such heaters may utilize one or more burners that inject fuel and / or oxidizer for combustion in a burner or combustion chamber to generate heat. The resulting combustion typically results in significant and undesirable amounts of NOx, such as NO, NO2, N2O, N2O3, and other nitrogen oxides. Carbon dioxide (CO2) is also formed during the combustion process when hydrocarbon fuels are burned.

[0011] Typically, catalytic reduction, advanced burner configurations, or both are used to attempt and reduce NOx emissions. However, catalytic reduction usually requires the use of ammonia (NH3) or urea (CH4N2O) and may require large scrubber beds, potentially leading to a significant increase in operating costs. Furthermore, the use of ammonia can result in ammonia leakage into flue gas or other fluids, which can cause equipment degradation and other problems. Advanced burners may also require additional investment costs associated with their installation and use. These approaches also reduce operational flexibility and may necessitate more maintenance operations during the combustion process.

[0012] We have determined that by providing an oxidant formed using an embodiment employing our mixing unit, reduced NOx formation from the combustion of hydrocarbon fuels can be achieved without the use of catalytic reduction and advanced burners. While advanced burners can be used due to other design requirements, in some embodiments of our equipment and methods for burning fuels with reduced NOx emissions, NOx reduction is not a primary concern, and these equipment and methods can utilize our oxidant mixing unit embodiments. Furthermore, we have surprisingly found that embodiments can be provided that also provide significant reductions in CO2 emissions by implementing different types of carbon capture devices.

[0013] For example, embodiments of our oxidizer mixing unit have surprisingly been found to form an oxidizer stream that can be fed into the combustion unit in a manner that helps to significantly reduce NOx formation that may occur during combustion and thus also significantly reduce NOx emissions. For instance, we have found that some embodiments of the methods and / or equipment utilizing our oxidizer mixing unit can provide a reduction of 80% to 98% in NOx formation from fuel combustion, or at least a reduction of 75% in NOx formation. We have found that this type of significant NOx reduction can be provided regardless of the type of burner or burner assembly used in the combustion process.

[0014] In a first aspect, an apparatus for oxidant formation may include a mixing device capable of being positioned and configured to receive carrier gas from at least one gas source and / or flue gas recirculated from a combustion unit. The mixing device may also be capable of being positioned and configured to receive oxygen from an oxygen source for injecting oxygen into the carrier gas to form an oxidant for feeding into the combustion unit. The mixing device may include a plurality of injection devices positioned within a conduit of the mixing device. The injection devices may be positioned downstream of at least one flow regulating device such that the carrier gas can pass through at least one flow regulating device before being conveyed along the injection devices. The injection devices may be positioned and configured to inject oxygen into the carrier gas to form an oxidant.

[0015] In some embodiments, the oxidant formed may be oxygen-enriched air. In other embodiments, the oxidant formed may be synthetic air. Some embodiments of the synthetic air formed may include synthetic air having a relatively low nitrogen (N2) content (e.g., N2 content between 25 mol% and 0 mol% N2). Some embodiments of the device may be configured to reduce nitrogen oxide formation during combustion. For example, some embodiments may be configured to form an oxidant for fuel combustion such that nitrogen oxide formation in the flue gas formed by fuel combustion can be below 6.1 mg / Nm³. 3 , where Nm 3 It is a standard cubic meter (e.g., at 6.1 mg / Nm³). 3 and greater than 0 mg / Nm 3 (between). As another example, some implementations can be configured to form an oxidant for the combustion of fuel, such that the formation of nitrogen oxides in the flue gas formed by combustion can be below 2.5 ppm (e.g., between 0 ppm and 2.5 ppm).

[0016] In a second aspect, the injection device may include: a central region of the injection device; a first outer region of the injection device located between the central region of the injection device and a first sidewall of the conduit; and a second outer region of the injection device located between the central region of the injection device and a second sidewall of the conduit. The central region of the injection device may be located between the first outer region of the injection device and the second outer region of the injection device. Multiple injection devices may be arranged in an alternating configuration within the conduit of the mixing device, or may be another type of configuration within the conduit of the mixing device.

[0017] In some embodiments, the first and second sidewalls may be spaced apart from each other by a bottom wall and a top wall opposite the bottom wall. The top and bottom walls may each extend along the width of the conduit of the mixing device between the first and second sidewalls to define a mixing device chamber, for example, for mixing oxygen with a carrier gas to form an oxidant. In such embodiments, the conduit of the mixing device may be rectangular or polygonal in shape.

[0018] In some embodiments, each injection device in the central region of the injection apparatus can be configured to inject oxygen at a certain mass flow rate into the carrier gas via the central region injection rate. Each injection device in the first outer region of the injection apparatus can be configured to inject oxygen at a certain mass flow rate into the carrier gas via the outer region injection rate, and each injection device in the second outer region of the injection apparatus can also be configured to inject oxygen at a certain mass flow rate into the carrier gas via the outer region injection rate. In some implementations, the central region injection rate can be the same as the outer region injection rate. In other embodiments, the central region injection rate can be different from the outer region injection rate. For example, the central region injection rate can be at least 5% larger than the outer region injection rate (e.g., 10% or 15% larger, etc.). As another example, the central region injection rate can be at least 10% larger than the outer region injection rate (e.g., between 10% and 30%, or between 10% and 35%, etc.). As yet another example, the injection rate in the central region can be at least 20% greater than the injection rate in the outer region (e.g., between 20% and 35%, etc.). As yet another example, the injection rate in the central region can be between 5% and 35% greater than the injection rate in the outer region.

[0019] In some embodiments, the mass flow rate of oxygen that can be injected into the carrier gas via the central region of the injection device can be between 30% and 60% of the total mass flow rate of oxygen that can be injected into the carrier gas. The mass flow rate of oxygen that can be injected into the carrier gas via the first outer region of the injection device can be between 20% and 40% of the total mass flow rate of oxygen that can be injected into the carrier gas, and the mass flow rate of oxygen that can be injected into the carrier gas via the second outer region of the injection device can be between 20% and 40% of the total mass flow rate of oxygen that can be injected into the carrier gas. In other embodiments, the mass flow rate of oxygen that can be injected into the carrier gas via the second outer region of the injection device can be equal to the mass flow rate of oxygen that can be injected into the carrier gas via the first outer region of the injection device.

[0020] In a third aspect, the conduit of the mixing device may have a conduit aspect ratio. The conduit aspect ratio may, for example, be greater than 3 or between 3.5 and 5. In other embodiments, the conduit aspect ratio may be between 3 and 6, or greater than 3 and less than 5.

[0021] Fourthly, the mixing device may include at least one flow regulating device. For example, perforated plates, deflector blades, baffles, tube bundles, and / or combinations of these flow regulating elements may be included as at least one flow regulating device. The flow regulating device may be configured to provide a uniform velocity profile for the carrier gas (e.g., air, flue gas, or a combination of air and flue gas, etc.) in the cross-section of the duct of the mixing device.

[0022] In some embodiments, at least one flow regulating device may include a perforated plate positioned within a duct upstream of the injection device. The perforated plate may have a thickness and a plurality of holes. Each hole may have a diameter. The ratio of the perforated plate's thickness to the hole diameter may be between 0.3 and 1. In some embodiments, the perforated plate may be positioned downstream of a carrier gas flow device or flow disturbance component (e.g., a deflector, branch, expansion / contraction section, damper, etc.), at a distance between half the height of the duct and three times the height of the duct.

[0023] In the fifth aspect, the device of the first aspect may include one or more features of the second, third, and / or fourth aspects. It should also be understood that other embodiments may utilize other elements or features. Examples of such other elements or features are provided in the exemplary embodiments discussed herein.

[0024] In a sixth aspect, a method for forming an oxidant is provided. The method may include forming the oxidant by mixing a carrier gas from at least one gas source and / or flue gas recirculated from a combustion device with oxygen from at least one oxygen source. The method may further include feeding the formed oxidant into the combustion device as an oxidant for burning fuel in the combustion chamber of the combustion device. The mixing of the carrier gas and oxygen may be carried out via a mixing device. The mixing device may include a plurality of injection devices positioned within a conduit of the mixing device. The injection devices may be positioned and configured to inject oxygen into the carrier gas to form the oxidant. The injection device may include: a central region of the injection device; a first outer region of the injection device positioned between the central region of the injection device and a first sidewall of the conduit; and a second outer region of the injection device positioned between the central region of the injection device and a second sidewall of the conduit. The central region of the injection device may be positioned between the first outer region of the injection device and the second outer region of the injection device.

[0025] Implementations of the apparatus for oxidant formation can be used in this method. The method may also utilize other steps or features. Some implementations of this method can, for example, be used in methods for reducing nitrogen oxide formation during combustion.

[0026] In some embodiments of this method, the oxidant formed may be oxygen-enriched air. In other embodiments, the oxidant formed may be synthetic air. Some embodiments of the synthetic air formed may include synthetic air having a relatively low nitrogen (N2) content (e.g., an N2 content between 25 mol% and 0 mol% N2). Some embodiments of this method can be implemented to reduce the formation of nitrogen oxides during fuel combustion. For example, some embodiments may be configured to form an oxidant for fuel combustion such that the formation of nitrogen oxides in the flue gas formed by fuel combustion can be below 6.1 mg / Nm³. 3 , where Nm 3 It is a standard cubic meter (e.g., at 6.1 mg / Nm³). 3 and greater than 0 mg / Nm 3 (between). As used in this article, Nm 3 It is a standard cubic meter, which is the volume of one cubic meter (m³) of gas in which the gas is absolutely dry, at a temperature of 0°C, and at an absolute pressure of 1 atm. 3 The volume of the gas. As another example, some embodiments can be configured to form an oxidant for the combustion of fuel, such that the formation of nitrogen oxides in the flue gas formed by combustion can be below 2.5 ppm (e.g., between 0 ppm and 2.5 ppm).

[0027] In a seventh aspect, the mixing of the carrier gas and oxygen may include injecting oxygen at a certain mass flow rate into the carrier gas via each injection device in the central region of the injection device at a central region injection rate, injecting oxygen at a certain mass flow rate into the carrier gas via each injection device in the first outer region of the injection device at an outer region injection rate, and injecting oxygen at a certain mass flow rate into the carrier gas via each injection device in the second outer region of the injection device at an outer region injection rate. The central region injection rate may be greater than the outer region injection rate (e.g., at least 5%, 10%, 20%, etc.). In some embodiments, the central region injection rate may, for example, be 5% to 35% greater than the outer region injection rate.

[0028] In the eighth aspect, the mixing of the carrier gas and oxygen may include injecting oxygen at a certain mass flow rate into the carrier gas via a central region of the injection device, injecting oxygen at a certain mass flow rate into the carrier gas via a first outer region of the injection device, and injecting oxygen at a certain mass flow rate into the carrier gas via a second outer region of the injection device. The mass flow rate of oxygen injected via the central region of the injection device may be between 30% and 60% of the total mass flow rate of oxygen injected into the carrier gas, the mass flow rate of oxygen injected via the first outer region of the injection device may be between 20% and 40% of the total mass flow rate of oxygen injected into the carrier gas, and the mass flow rate of oxygen injected via the second outer region of the injection device may be between 20% and 40% of the total mass flow rate of oxygen injected into the carrier gas. In some embodiments, the features of the seventh aspect and the eighth aspect may be performed simultaneously.

[0029] In some embodiments, the mass flow rate of oxygen injected into the carrier gas by each injection device in the second outer region of the injection device may be equal to the mass flow rate of oxygen injected into the carrier gas by each injection device in the first outer region of the injection device. Furthermore (or alternatively), the mass flow rate of oxygen injected through each injection device in the central region of the injection device may be at least 20% higher than the mass flow rate of oxygen injected into the carrier gas by each injection device in the first outer region of the injection device, and the mass flow rate of oxygen injected through each injection device in the central region of the injection device may also be at least 20% higher than the mass flow rate of oxygen injected into the carrier gas by each injection device in the second outer region of the injection device. In other embodiments, the mass flow rate of the injection devices in the central region of the injection device may vary within other ranges.

[0030] In a ninth aspect, the method for forming an oxidant may further include passing a carrier gas through at least one flow regulating device positioned upstream of the injection device. In some embodiments, the at least one flow regulating device may comprise a perforated plate having a thickness and a plurality of holes, wherein each hole has a hole diameter. The carrier gas can pass through the holes in the perforated plate, wherein the ratio of the thickness of the perforated plate to the hole diameter is between 0.3 and 1. The perforated plate may be positioned downstream of a carrier gas flow device or flow disturbance component (e.g., a deflector, branch, expansion / contraction section, damper, etc.) at a distance between half the height of the conduit and three times the height of the conduit. Embodiments may further include positioning the perforated plate in a conduit of a mixing device upstream of the injection device.

[0031] In the tenth aspect, the method of the sixth aspect may include one or more features of the seventh, eighth, and / or ninth aspects. It should also be understood that other embodiments may utilize other elements or features. Examples of such other elements or features are provided in the exemplary embodiments discussed herein.

[0032] Eleventhly, a combustion apparatus is provided. Embodiments of the combustion apparatus can utilize embodiments of apparatus for oxidant formation. Embodiments of the combustion apparatus can also be configured to implement embodiments of methods for forming an oxidant and / or embodiments of apparatus for reducing nitrogen oxide formation during combustion.

[0033] For example, in some embodiments, the combustion apparatus may include a combustion unit and a mixing unit positioned and configured to receive carrier gas from at least one gas source and / or flue gas recirculated from the combustion unit. The mixing unit may also be positioned and configured to receive oxygen from an oxygen source for injecting oxygen into the carrier gas to form an oxidant for feeding into the combustion unit. At least one flow regulating device may be positioned upstream of the mixing unit. The mixing unit may include multiple injection devices positioned within a conduit of the mixing unit. Injection devices may be positioned downstream of at least one flow regulating device such that the carrier gas can pass through at least one flow regulating device before being conveyed along the injection device. At least one flow regulating device may be configured to provide a uniform velocity profile for the carrier gas conveyed along the injection device along the cross-section of the conduit of the mixing unit. The injection device may be positioned and configured to inject oxygen into the carrier gas to form an oxidant. The injection device may include: a central region of the injection device; a first outer region of the injection device positioned between the central region of the injection device and a first sidewall of the conduit; and a second outer region of the injection device positioned between the central region of the injection device and a second sidewall of the conduit. The central region of the injection device can be located between the first outer region and the second outer region of the injection device. Each injection device in the central region of the injection device can be configured to inject oxygen at a certain mass flow rate into the carrier gas via the central region injection rate, each injection device in the first outer region of the injection device can be configured to inject oxygen at a certain mass flow rate into the carrier gas via the outer region injection rate, and each injection device in the second outer region of the injection device can be configured to inject oxygen at a certain mass flow rate into the carrier gas via the outer region injection rate. The central region injection rate can be at least 5% greater than the outer region injection rate. Furthermore, the aspect ratio of the conduit of the mixing device can be between 3 and 5 (e.g., greater than 3 and less than or equal to 4.5, etc.).

[0034] Other embodiments of the combustion device may have other features. For example, an oxidant feed duct may be positioned between the mixing unit and the combustion chamber of the combustion device to feed oxidant into the combustion chamber (e.g., via at least one burner and / or via at least one oxidant inlet of the combustion chamber). The combustion device may be configured for steam reforming, may be configured as a furnace, may be configured as a boiler, or may be configured as another type of device that can utilize the combustion of fuels (e.g., at least one hydrocarbon, methane, pulverized coal, petroleum, refinery exhaust gas, etc.).

[0035] It should be understood that implementations of this method and apparatus can utilize a variety of conduit arrangements and process control elements. These implementations can utilize sensors (e.g., pressure sensors, temperature sensors, flow rate sensors, concentration sensors, etc.), controllers, valves, piping, and other process control elements. Some implementations, for example, can utilize automated process control systems and / or distributed control systems (DCS). A wide variety of conduit arrangements and process control systems can be used to meet a specific set of design criteria.

[0036] Further details, objectives, and advantages of our apparatus for oxidant formation, methods for oxidant formation, combustion apparatus, and methods of manufacture and use thereof will become apparent from the following description of certain exemplary embodiments. Attached Figure Description

[0037] Exemplary embodiments of our apparatus for oxidant formation, methods for oxidant formation, methods for reducing nitrogen oxide formation during combustion, apparatus for reducing nitrogen oxide formation during combustion, and methods of manufacture and use thereof are illustrated in the accompanying drawings contained herein. It should be understood that the same reference numerals used in the drawings may identify the same parts.

[0038] Figure 1 This is a block diagram of a first exemplary embodiment of a device for reducing the formation of nitrogen oxides during combustion, which may include our first exemplary embodiment of a device for oxidant formation.

[0039] Figure 2 This is a schematic diagram of a first exemplary embodiment of an apparatus for oxidant formation, wherein the top wall of the apparatus's conduit has been removed to help illustrate the positioning of an injection device 7i (e.g., a diffuser, etc.) that can be positioned within the apparatus's conduit for injecting oxygen into the conduit for mixing with a carrier gas.

[0040] Figure 3 This is a schematic block diagram of a first exemplary embodiment of an apparatus for oxidant formation.

[0041] Figure 4This is a graph illustrating the results of computational fluid dynamics (CFD) modeling, which illustrates the peak oxygen concentration ("peak O2 mole fraction") at the duct surface for different oxygen / carrier gas mass flow ratios ("O2 / carrier gas mass flow ratio").

[0042] Figure 5 This is a graph illustrating the results of a CFD modeling study, which shows the overall peak oxygen concentration ("peak O2 mole fraction at the duct wall") at the outlet 7° of the device used for oxidant formation for different aspect ratios ("O2 / carrier gas mass flow rate ratio").

[0043] Figure 6 This is a graph illustrating the results of a CFD modeling study, which shows the peak oxygen concentration ("peak O2 mole fraction") at the catheter surface for different catheter aspect ratios ("catheter aspect ratio").

[0044] Figure 7 This is a graph illustrating the results of a CFD modeling study, which shows the overall peak oxygen concentration (“downstream peak O2 concentration”) at the outlet 7° of the equipment used for oxidant formation for different aspect ratios (“O2 / carrier gas mass flow ratio”).

[0045] Figure 8 These are a series of oxygen concentration diagrams illustrating the oxygen concentration profile at the bottom wall of the conduit downstream of the location where oxygen is injected into the carrier gas to form the oxidant. Top diagram GrA illustrates the mole fraction of oxygen (O2 or O2) in a first exemplary embodiment for oxidant formation under the condition that oxygen is injected at the same rate for all injection devices 7i. Bottom diagram GrB illustrates the mole fraction of oxygen (O2 or O2) in a first exemplary embodiment for oxidant formation under the condition that oxygen is injected at a higher rate into the central region of the injection device 7i and at a lower rate into the injection devices 7i adjacent to the sidewall 7sw (e.g., the opposite side of the central region, which can also be considered as the relatively outer region of the injection device 7i located opposite the central region of the injection device 7i, thus each outer region lies between the central region and the sidewall 7sw of the mixing device conduit).

[0046] Figure 9 This is a flowchart illustrating a first exemplary embodiment of a method for oxidant formation, which can be used in exemplary embodiments of a method for reducing nitrogen oxide formation during combustion. A first exemplary embodiment of a device for reducing nitrogen oxide formation during combustion and / or a first exemplary embodiment of a device for oxidant formation can be implemented. Figure 9 The first exemplary implementation of the method shown is described. Detailed Implementation

[0047] refer to Figures 1-3 The combustion device 1 may include a combustion apparatus 3, which may have one or more burners 3b; and may also include an oxidant formation device 2 for feeding the formed oxidant into the combustion apparatus 3. Each burner in the burners 3b may inject fuel into the combustion chamber for combustion within the combustion apparatus 3. The fuel may include hydrocarbon fuels (e.g., pulverized coal, petroleum, natural gas, etc.) and / or other fuels (e.g., hydrogen) that may be supplied by pipelines, industrial process elements, fuel storage units, and / or other fuel sources. The burners and / or other inlets may also feed the oxidant formed via the oxidant formation device 2 into the combustion apparatus for fuel combustion.

[0048] For example, each burner 3b, or at least one burner in burner 3b, may also receive an oxidant stream (oxidant) for feeding into the combustion chamber along with the fuel. Alternatively (or additionally), at least one oxidant stream may be fed into a combustion chamber upstream or downstream of one or more burners 3b to promote combustion of the fuel therein. Combustion of the fuel can generate heat and form flue gas containing combustion products of the burned fuel. The combustion products contained in the flue gas may include water, carbon dioxide, and a small amount of carbon monoxide. The flue gas may also include nitrogen oxides (NOx).

[0049] In some embodiments, the combustion device 3 may be configured to heat a feed that can be fed into the combustion device 3. The feed may be, for example, water for generating steam. As another example, the feed may be material to be heated by combustion to produce a reaction to form one or more desired products. In yet another embodiment, the combustion device 3 may be a boiler for generating steam or a furnace configured to provide heat for melting glass, metal, or other materials. Embodiments of the combustion device 3 may be configured to facilitate power generation, electricity generation, facilitate a steam / hydrocarbon reforming process, or may be used in another method in which combustion is required. For example, the combustion device 3 may be or may include a gas turbine, furnace, boiler, or steam reformer (e.g., a steam-methane reformer). The combustion device 3 may also be other types of burners or devices used in combustion-based methods that use oxidants to burn fuel.

[0050] Each burner 3b of the combustion device 3 can be any type of suitable burner or arrangement of burners. Some embodiments of the combustion device 3 may have a single burner. Other embodiments may utilize multiple burners. Each burner 3b may include a nozzle device for feeding fuel or a mixture of fuel and oxidant into the combustion chamber for combustion therein. Different types of burners 3b may be used. For example, a staged, non-premixed oxidant burner may be used, or an oxidant premixed burner may be used.

[0051] At least one oxidant stream can be supplied to the combustion device 3 to promote the combustion of fuel and / or feed therein. The oxidant can be an oxygen-enriched air stream or a synthesis air stream. In embodiments utilizing oxygen-enriched air, the air can be a gas source 4 (GS), which can be fed to the mixing device as feed gas FG. Oxygen from an oxygen source 5 can be fed to the mixing device 7 for injection into the carrier gas FG to form an oxidant, which can be oxygen-enriched air. In some embodiments, the oxygen-enriched air can be between 22 mol% and 35 mol% oxygen. In such embodiments, nitrogen can constitute the bulk remainder of the oxidant (e.g., between 78 mol% and 70 mol% nitrogen (N2)). Trace amounts of carbon dioxide (CO2), carbon monoxide (CO), water (H2O), and argon (Ar) and other trace elements (e.g., helium) may also be present in such oxygen-enriched oxidants. The oxygen-enriched oxidant can be formed by an air feed as a carrier gas FG, which has oxygen injected into it for mixing therein to form the oxidant.

[0052] In other embodiments, oxygen-enriched air may be provided, wherein the carrier gas comprises air from gas source 4 (GS) and recirculated flue gas RFG, which is mixed with air to form carrier gas FG before being fed into mixing unit 7. In such embodiments, oxygen-enriched air may include significantly higher concentrations of CO2 and water compared to oxygen-enriched air formed by injecting oxygen into a carrier gas containing only air.

[0053] In other embodiments, the oxidant formed may be synthetic air, thereby avoiding or minimizing the use of ambient air or oxygen-enriched air. For example, although the initial combustion of fuel in the combustion chamber of the combustion device 3 may be provided via oxygen-enriched air during initial startup, after initial startup has taken place, the oxidant used for combustion may be changed or switched to synthetic air, so that the use of air or oxygen-enriched air can be stopped and no longer used to provide oxidant for combustion. Instead, after switching to synthetic air, only the synthetic air formed may be provided to the combustion device 3 as an oxidant for fuel combustion.

[0054] In other embodiments, even the start-up of the combustion device 3 can be provided by using syngas, thus eliminating the need for air or oxygen-enriched air. For example, the gas source 4 (GS) for forming the syngas can be a CO2 source (e.g., a CO2 pipeline, a CO2 storage tank, etc.), and / or another apparatus method for providing flue gas for mixing with oxygen to form an oxidant, and the flue gas can be sufficiently present at the start-up of the combustion device 3 (e.g., via storage in a tank and / or via the method element), thus eliminating the need for any air or oxygen-enriched air.

[0055] The oxidant used to form synthetic air can be formed via a mixing device 7 of the apparatus 2 for oxidant formation. The mixing device 7 can receive a carrier gas FG and / or a recirculated stream of flue gas from at least one flue gas source, which can be recirculated from flue gas formed by combustion in the combustion unit 3, and can be discharged from the combustion unit 3 via a flue gas duct 3e. For example, the gas source 4 may include flue gas from an industrial equipment component or industrial equipment processing unit, which may generate flue gas via combustion or other methods and be connected to the mixing device 7 for feeding the flue gas into the mixing device 7. The flue gas may also, or alternatively, include flue gas formed in the combustion unit 3, which is subsequently fed into the mixing device 7 as recirculated flue gas RFG via a flue gas recirculation duct 3r connected between the mixing device 7 and the flue gas outlet duct 3e of the combustion unit 3.

[0056] The exact composition of flue gas can vary based on the type of industrial process used to generate it and / or the type of fuel burned to form it. In many embodiments, the flue gas may include carbon dioxide and water, as well as other components (e.g., carbon monoxide, argon, nitrogen, etc.). Carbon dioxide may be a significant component of the flue gas (e.g., between 40 mol% and 70 mol%). The flue gas may also contain water between 5 mol% and 60 mol% and nitrogen between 0 mol% and 30 mol%.

[0057] The flue gas may also include argon, helium, carbon monoxide, or other components. For example, the flue gas may have 0 mol% argon to 5 mol% argon, 0 mol% carbon monoxide to 0.5 mol% carbon monoxide, and 0 mol% helium to 1 mol% helium.

[0058] The mixing unit 7 can also receive oxygen (O2) from at least one oxygen source 5 (O2) for mixing with the flue gas to form syngas as an oxidant to be fed into the combustion unit 3. The oxygen can be 100 mol% oxygen, or it can be from 100 mol% oxygen to 98 mol% oxygen, or it can be from 85 mol% oxygen to 100 mol% oxygen. In other embodiments, the oxygen from the oxygen source 5 can also have another suitable oxygen concentration.

[0059] The oxygen source 5 may include, for example, liquid oxygen stored in a cryogenic oxygen tank, which may be vaporized and subsequently fed into a buffer tank for feeding into the mixing unit 7; oxygen stored in an oxygen tank; oxygen output from an air separation unit (ASU); oxygen formed by a vacuum pressure swing adsorption (VSA) method; or other suitable oxygen sources.

[0060] The synthesized air formed, used as an oxidant, can have a significant amount of carbon dioxide (CO2) and 20 mol% to 30 mol% O2. For example, the CO2 content of the synthesized air formed can be between 30 mol% and 80 mol% or between 30 mol% and 60 mol%. Water (H2O) may also be included in the synthesized air to help suppress the formation of NOx due to combustion in the combustion chamber of the combustion device 3. In some embodiments, water can be between 2 mol% and 40 mol% of the synthesized air. In other embodiments, water may be absent or may be present only in relatively trace amounts (e.g., water may be between 0 mol% and 5 mol% of the synthesized air).

[0061] In some embodiments, synthetic air can be formed such that a preselected ratio of water to CO2 (water / CO2) is present. In some embodiments, this preselected ratio may be 0.8, between 0 and 1.1, or between 0.7 and 0.9. Other embodiments may also utilize another suitable ratio, which can be configured to meet a specific set of design criteria.

[0062] The water contained in the synthetic air may include water from the flue gas. In some embodiments, water may also be provided by injecting water from a water source into the flue gas via the mixing device 7 or a water injection mechanism located upstream of the mixing device 7.

[0063] The resulting syngas may contain trace amounts of nitrogen, far less than that found in air or oxygen-enriched air. For example, the resulting syngas may include 20 mol% oxygen (O2) to 40 mol% O2, 0 mol% argon (Ar) to 2 mol% Ar, 2 mol% nitrogen (N2) to 20 mol% N2, 5 mol% water to 40 mol% water, and 30 mol% carbon dioxide (CO2) to 60 mol% CO2. The resulting syngas may also contain other components, such as small or trace amounts of carbon monoxide (CO) and helium (he).

[0064] For example, mixing device 7 can be configured to use oxygen and flue gas to form syngas, which may contain 30 mol% to 60 mol% CO2, 23 mol% to 28 mol% O2, 1 mol% to 2 mol% Ar, 5 mol% to 15 mol% N2, and 5 mol% to 40 mol% water. As another example, mixing device 7 can be configured to use oxygen and flue gas to form syngas, which may contain 30 mol% to 70 mol% CO2, 20 mol% to 35 mol% O2, 1 mol% to 2 mol% Ar, 5 mol% to 20 mol% N2, and 2 mol% to 40 mol% water.

[0065] As yet another example, the mixing device 7 can be configured to form syngas, which may contain less than 15 mol% or less than 10 mol% N2. Preferably, the N2 concentration in the formed syngas is minimized or otherwise kept relatively low (e.g., less than 20 mol% or less than 15 mol%). However, N2 may enter the combustion chamber due to imperfect seals and / or, over time, due to other imperfect sealing conditions, exposure of the combustion chamber to atmospheric air. This can be particularly problematic when the flue gas FG used to form the syngas is formed by combustion in the combustion chamber and is recirculated as recirculated flue gas RF to provide the flue gas source for the syngas FG used to form the syngas. In such cases, although the N2 concentration of the synthesized air may initially be about 0 mol%, or between 10 mol% and 0 mol%, or between 5 mol% and 0 mol%, the N2 concentration in the synthesized air may increase to a higher concentration over time (e.g., between 5 mol% and 15 mol%, or between 5 mol% and 20 mol%).

[0066] In other cases (e.g., newer combustion apparatus facilities), seals and other potential locations for ambient air ingress may not be significant issues. In such cases, the resulting synthesis air can be maintained such that the N2 concentration is below 20 mol%, preferably below 12 mol%, and most preferably between 10 mol% and 0 mol%. In some embodiments, the resulting synthesis air is expected to have 0 mol% N2 or only trace amounts of N2 (e.g., 0 mol% N2 to 1 mol% N2).

[0067] We have found that using synthetic air as an oxidant in the combustion chamber of combustion device 3 can promote low NOx formation during fuel combustion. Using synthetic air with a low N2 concentration helps avoid the presence of nitrogen, which contributes to NOx formation. Furthermore, the synthetic air can include relatively high concentrations of CO2 and water, which can further help suppress NOx formation. We have surprisingly found that embodiments of combustion device 1 utilizing synthetic air with such low N2 concentrations and relatively high concentrations of water and CO2 can provide a significant reduction in NOx formation (e.g., a 75% to 95% reduction in NOx formation compared to using air as an oxidant or using oxygen-enriched air as an oxidant; e.g., in some embodiments, the oxidant stream has 70 mol% to 79 mol% N2 and 20 mol% to 28 mol% O2).

[0068] Synthetic air can be fed into the combustion unit 3 after being formed by injecting oxygen into the flue gas in various ways via the mixing device 7. For example, synthetic air can be fed into the combustion unit via an annular duct of at least one burner 3b, which is fluidly connected to the mixing device 7 via a burner feed duct between the mixing device 7 and the burner 3b. As another example, synthetic air can be fed into the combustion unit 3 via one or more combustion chamber inlets, which are fluidly connected to the mixing device 7 via at least one oxidizer feed duct 6 (shown in dashed lines) connecting the mixing device 7 and the combustion unit 3.

[0069] We have also found that using synthetic air with a high CO2 concentration can be beneficial for carbon capture to avoid CO2 emissions and / or to form at least one CO2 product stream from the operation of the combustion unit 3. For example, flue gas output from the combustion unit 3 via flue gas output duct 3e can be fed to the carbon capture device 11 for processing the flue gas to form at least one CO2 product stream 11p. In some embodiments, a first portion of the output flue gas can be fed to the carbon capture device 11, and a second portion of the output flue gas can be fed to the mixing unit 7 as a gas source via a flue gas recirculation duct 3r connected between the mixing unit 7 and the combustion unit 3. The first portion of the flue gas fed to the carbon capture device 11 can be 30% to 70% of the flue gas output from the combustion unit, and the second portion of the flue gas recirculated back to the mixing unit 7 can be the remainder of the flue gas (e.g., 70% to 30% of the flue gas output from the combustion unit 3). For example, during operation, the proportion of the output flue gas recirculated back to the mixing unit 7 can vary from a large portion (e.g., close to 70%) to a small portion (e.g., 30% or 35%), and the portion of the output flue gas fed into the carbon capture device 11 can also vary accordingly (e.g., close to 30% of the output flue gas when the large portion is recirculated, and close to or at 70% of the output flue gas when the small portion of the flue gas is recirculated back to the mixing unit 7).

[0070] For example, when the CO2 content of the synthesis air is high, the proportion of flue gas fed into the carbon capture device 11 can be relatively high (e.g., 50% to 70% of the output flue gas) to promote more efficient capture of carbon dioxide from the flue gas. Conversely, when the flue gas concentration can have a lower CO2 content, the proportion of flue gas fed into the carbon capture device 11 can be relatively low (e.g., close to 30% of the output flue gas).

[0071] The proportion of flue gas generated by combustion in the combustion device, diverted through flue gas outlet duct 3e for carbon capture and recirculation to the mixing unit 7, can be adjusted to other proportions. For example, each portion can be 50%, or the first portion fed to the carbon capture device 11 can be 40% to 60% of the flue gas output from the combustion device 3 via flue gas outlet duct 3e, and the remaining portion of the flue gas can be recirculated back to the mixing unit 7 as recirculated flue gas RFG. In yet another embodiment, some of the flue gas can be sent along different routes (e.g., another portion of the flue gas can be provided for flue gas emission, or the first portion of the flue gas can be emitted instead of being fed to the carbon capture device 11, and the second portion can be recirculated back to the mixing unit 7).

[0072] We have found that obtaining a high CO2 content in the flue gas formed by combustion in the combustion device 3 allows for more efficient separation of CO2 from the flue gas and enables greater CO2 recovery. For example, some embodiments can facilitate the capture and recovery of 95% or more of the CO2 in the flue gas formed by combustion in the combustion chamber of the combustion device 3. Moreover, the CO2 concentration in the CO2 product stream 11p generated and output from the carbon capture device 11 can be high (e.g., 95 mol% CO2, 95 mol% to 100 mol% CO2, greater than or equal to 90 mol% CO2 but less than 100 mol% CO2, etc.).

[0073] As from Figure 2 and Figure 3 As best understood, embodiments of the apparatus 2 for oxidant formation may include a mixing device 7, which may be configured to form the oxidant as oxygen-enriched air or synthetic air (examples of oxidants that can be formed via the mixing device 7 are discussed herein). Oxygen from an oxygen source 5 may be fed into a plurality of injection devices 7i positioned within a conduit 8 of the mixing device 7. In some embodiments, the conduit 8 of the mixing device 7 may be a rectangular conduit having an aspect ratio between 1.5 and 5 or between 2 and 4. Other embodiments may utilize different aspect ratios (e.g., ratios greater than 5, etc.). The conduit 8 of the mixing device 7 may also receive a carrier gas FG for forming the oxidant by injecting oxygen into the carrier gas FG via a carrier gas inlet 7f of the conduit 8 of the mixing device 7. The carrier gas inlet 7f may be located at an end of the conduit 8 of the mixing device 7, opposite to an outlet 7o of the conduit 8 of the mixing device 7.

[0074] The injection device 7i may be, for example, a diffuser or other type of injector. Each injection device 7i may have multiple oxygen injection holes along the periphery or circumference of its body. The body of the injection device 7i may be a tube (e.g., a cylindrical tube with peripheral holes for oxygen injection, a polygonal tube with peripheral holes for oxygen injection, etc.). The body of each injection device 7i may be positioned such that its length extends along the height H of the conduit, and the diameter of the injection device body extends along the width W and / or length L of the conduit perpendicular to the height H of the conduit. The injection device 7i may have an inlet fluidly connected to the oxygen source 5 for receiving oxygen, for discharging the oxygen as an oxygen jet O2i within the conduit 8 of the mixing device 7 from the holes of the injection device 7i for mixing with the carrier gas conveyed along the injection device 7i.

[0075] The injection device 7i can be positioned and configured to inject oxygen at a pre-selected injection pressure into a carrier gas conveyed along the injection device 7i. The pre-selected injection pressure can be a suitable pressure within a pre-selected oxygen injection pressure range that meets a pre-selected set of design criteria. In some embodiments, the pre-selected oxygen injection pressure range may be between 137 kPa and 276 kPa, or between 150 kPa and 240 kPa (e.g., 207 kPa, between 205 kPa and 215 kPa, etc.).

[0076] Oxygen injection holes defined in each injection device of the injection device 7i can be vertically spaced apart from each other, and multiple rows of differently spaced holes are formed at different positions along the height of the main body of the injection device 7i. These holes can be positioned in the conduit 8 of the mixing device 7 and extend along the height H of the conduit. Oxygen from the oxygen source 5 can be injected as an oxygen jet O2i, which can flow out from the holes of the injection device 7i and be injected into the carrier gas FG, which passes through the conduit 8 of the mixing device 7 along the length L of the conduit, so that the carrier gas passes along the injection device 7i to receive the oxygen jet O2i for mixing the oxygen in the carrier gas FG to form an oxidant. The oxidant can be formed downstream of the injection device 7i and before the oxidant is discharged from the outlet 7o of the conduit 8 of the mixing device 7.

[0077] The injection device 7i can be positioned in a staggered arrangement. An example of a staggered arrangement can be found in... Figure 2 and Figure 3 This is best seen in the diagram. For example, the injection devices 7i can be arranged in the conduit in rows R of spaced-apart injection devices 7i and columns C of spaced-apart injection devices 7e. Rows R can extend along a portion of the length L of the conduit 8 of the mixing device 7. Columns C can extend along the width W of the conduit 8 of the mixing device 7.

[0078] Each injection device 7i can be located within a corresponding column C of injection devices, and spaced apart by a column distance dc from the immediate adjacent injection device in that column C. Each injection device 7i can also be located in a corresponding row of row R of injection devices 7i. Each injection device 7i can be spaced apart by a row distance dr from the immediate adjacent injection device 7i in its row R. The row distance dr and column distance dc can be selected to meet a pre-selected set of design criteria to facilitate the mixing of the oxygen jet O2i with the carrier gas, so that the oxidant is formed before exiting from the outlet 7o of the conduit 7.

[0079] The staggered injection devices 7i can also be spaced apart from other adjacent injection devices in adjacent columns or rows by column and row distances dcr. The row and column staggering can be selected such that the column and row distances dcr are the distances between injection devices 7i in a specific row R and column C (e.g., the first row and first column) and another adjacent injection device 7i in another row R and another column C (e.g., the second row and second column). The spacing of the row distance dr, column distance dc, and column and row distance dcr can be selected to define a pre-selected staggered pattern to meet a pre-selected set of design criteria for mixing oxygen injected into the carrier gas FG before the oxidant is output from the outlet 7o of the conduit 8 of the mixing device 7 to form the oxidant.

[0080] The columns C of injection devices 7i can be arranged such that the first injection device 7i in each column is positioned adjacent to the first sidewall 7sw of the conduit 8 of the mixing device 7 and is the first end injection device of column C of injection devices 7i. The second injection device 7i in each column can be positioned adjacent to the second sidewall 7sw of the conduit 8 of the mixing device 7 and can be the second end injection device of column C of injection devices 7i. Multiple other injection devices can be present in each column between the first and second injection devices. Some of these third injection devices 7i can define a central region of the injection device 7i.

[0081] The first outer region 1OR of the injection device 7i may include the injection device 7i closest to the first sidewall 7sw, and the second outer region 2OR of the injection device 7i may include the injection device closest to the second sidewall 7sw. The central region CR of the injection device may be located between the first outer region 1OR and the second outer region 2OR of the injection device 7i.

[0082] For example, the central region CR may include one or more rows of injection devices 7i positioned between at least a first outer row of injection devices 7i positioned adjacent to a first sidewall 7sw and at least a second outer row of injection devices 7i positioned adjacent to a second sidewall 7sw. In some embodiments, each outer region may include only a single row, at least two outer rows, or at least three outer rows. In such embodiments, the central region CR may include at least two rows of injection devices 7i or at least three rows of injection devices 7i.

[0083] In some embodiments, the mixing device 7 can be arranged and configured such that the flow rate of oxygen injected via the injection device 7i differs from that of the central region CR injection device and the external region injection devices of the first outer region 1OR and the second outer region 2OR. For example, in some configurations or embodiments, the central region of the injection device can inject 50%-60% of the total mass of injected oxygen, and the external region injection device 7i of each outer region can inject 25% to 20% of the total mass of injected oxygen. In other embodiments, the central region CR injection device 7i can inject 40% to 55% of the total mass of oxygen into the carrier gas FG, and each external region injection device 7i can inject 30% to 22.5% of the total mass of oxygen into the carrier gas FG. In some embodiments, the external region injection devices of the first outer region 1OR and the second outer region 2OR can provide a net oxygen injection of 5% to 30% less into the conduit than the oxygen injected via the central region CR injection device 7i.

[0084] Furthermore, the oxygen flow rate injected by each injection device in each external region may differ from the oxygen flow rate injected by each injection device in the central region CR by at least 10% or at least 20% (e.g., the injection rate is between 10% and 35% higher than the injection rate of the injection devices used for external regions 1OR or 2OR, etc.). For example, each injection device in the central region CR injection device 7i may inject oxygen at a mass flow rate at least 20% higher than the mass flow rate of each injection device 7i in the first external region 1OR. Similarly, each injection device in the central region CR injection device 7i may inject oxygen at a mass flow rate at least 20% higher than the mass flow rate of each injection device 7i in the second external region 2OR.

[0085] As another example, each injection device in the injection device 7i of the central region CR can inject oxygen at a mass flow rate at least 10% higher than that of each injection device 7i in the first outer region 1OR (e.g., between 10% and 35%, more than 30%, more than 20%, etc.). Each injection device 7i in the central region CR can also inject oxygen at a mass flow rate at least 10% higher than that of each injection device 7i in the second outer region 2OR (e.g., between 10% and 35%, etc.).

[0086] In some other embodiments, each injection device in the injection device 7i of the central region CR can inject oxygen at a mass flow rate at least 5% higher (e.g., between 5% and 35%, more than 10%, more than 20%, etc.) than the mass flow rate of each injection device 7i of the first outer region 1OR. Each injection device in the injection device 7i of the central region CR can also inject oxygen at a mass flow rate at least 5% higher (e.g., between 5% and 35%, etc.) than the mass flow rate of each injection device 7i of the second outer region 2OR.

[0087] In some implementations, each injection device in the first outer region 1OR and the second outer region 2OR can inject oxygen at an outer region flow rate, and each injection device in the central region CR can inject oxygen at a central region flow rate. The central region flow rate used via the central region injection device can be at least 20% higher (e.g., between 20% and 35%) than the outer region flow rate used by the injection devices in the first outer region 1OR and the second outer region 2OR. In other embodiments, the central region flow rate used via the central region injection device can be between 5% and 35% higher than the outer region flow rate used by the injection devices in the first outer region 1OR and the second outer region 2OR. As yet another example, the central region flow rate used via the central region injection device can be at least 10% higher (e.g., between 10% and 35%) than the outer region flow rate used by the injection devices in the first outer region 1OR and the second outer region 2OR.

[0088] We have found that making the flow rate of each injection device 7i in the central region CR greater than the flow rate of oxygen injected through each injection device in the first outer region 1OR and the second outer region 2OR can surprisingly provide improved fluid mixing to provide a more desirable oxygen concentration profile in the formed oxidant. This can help avoid higher peak oxygen concentrations adjacent to the conduit wall, thus helping to avoid potential degradation due to such walls being exposed to excessively high oxygen concentrations (e.g., oxygen concentrations exceeding 40 mol% O2).

[0089] The injection device 7i and conduit 8 of the mixing device 7 can be arranged and configured such that a preselected pressure drop occurs when the carrier gas FG passes through the conduit to mix with the injected oxygen jet O2i and form an oxidant. In some embodiments, this preselected pressure drop can be between 24 Pa and 250 Pa (e.g., it can be 50 Pa or other values ​​within the range of 24 Pa and 250 Pa). Other embodiments can utilize another suitable pressure drop to accommodate a different set of criteria.

[0090] The mixing device 7 may also include at least one flow regulating device 7p, which may be positioned upstream of the injection device 7i to regulate the carrier gas FG fed into the mixing device 7 for the formation of the oxidant. For example, the flow regulating device 7p may include, for example, a perforated plate, a deflector blade, a baffle, a tube bundle, and / or a combination of these flow regulating elements. In some embodiments, the flow regulating device 7p may be positioned downstream of a carrier gas flow device that helps drive the carrier gas flow through the mixing device 7 (e.g., a fan, booster, blower, compressor, etc.); or downstream of a flow disturbance component (e.g., a deflector, branch, expansion / contraction section, damper, etc.), at a distance between half the height H of the duct 8 of the mixing device 7 and twice the height H of the duct (e.g., the flow regulating device 7p may be positioned at a distance between 0.5 times and 2 times the height H of the duct, or between a distance equal to or 1.5 times the height H of the duct, etc.).

[0091] Other embodiments may utilize other types of spacing. For example, some embodiments may be configured such that the flow regulating device 7p can be positioned downstream of the carrier gas flow device, which helps drive the carrier gas flow through the mixing device 7 (e.g., fan, booster, blower, compressor, etc.); or positioned downstream of the flow disturbance component (e.g., deflector, branch, expansion / contraction section, damper, etc.), at a distance between half the height H of the duct 8 of the mixing device 7 and three times the height H of the duct (e.g., the flow regulating device 7p may be positioned at a distance between 0.5 times and 3 times the height H of the duct, or between a distance equal to or 2.5 times the height H of the duct, etc.).

[0092] The flow regulating device 7p can be positioned and configured to provide a uniform velocity profile for the carrier gas FG (e.g., air, flue gas, or a combination of air and flue gas as discussed above) in the cross-section of the duct 8 of the mixing device 7. For example, when the duct is a rectangular duct, the flow regulating device 7p can be positioned and configured such that the carrier gas has a uniform velocity profile along the cross-section of the rectangular duct (e.g., along the width W and height H of the duct).

[0093] In some embodiments, the flow regulating device 7p may include a perforated plate having a plurality of holes extending through the thickness of the plate. Each hole may have a hole diameter, which may also be considered as a hole width. The perforated plate may be positioned such that the length of the plate extends along the width W of the conduit 8 of the mixing device. For example, the length of the perforated plate may extend between a first sidewall 7sw and a second sidewall 7sw of the mixing device conduit (e.g., having opposite ends that contact or are integrally attached to the opposite sidewall 7sw). The perforated plate may also have a height extending along the height H of the conduit between the bottom 7b and the top of the conduit. The bottom 7b of the conduit 8 of the mixing device 7 may extend along the length L of the conduit between the sidewalls 7sw, and the top of the conduit may be opposite to the bottom 7b and also extend along the length L of the conduit between the sidewalls 7sw. The bottom of the perforated plate may extend along the bottom of the conduit between its sidewalls 7sw and be integrally attached to or contact the bottom 7b of the conduit. The top of the perforated plate may extend along the top of the conduit between its sidewalls 7sw and be integrally attached to or in contact with the top of the conduit.

[0094] The perforated plate may have a thickness extending along the length L of the duct, such that it extends in the flow direction of the carrier gas FG. The perforated plate may have a thickness-to-diameter ratio of 0.8 and higher (e.g., greater than 0.8, greater than 1.0, etc.). Preferably, the thickness-to-diameter ratio of the plate is at least 0.3 or higher, such that the perforated plate can provide a uniform velocity profile for the carrier gas FG passing through the orifices of the plate.

[0095] We have found that the mixing device 7 can significantly improve oxygen mixing in the conduit 8 of the mixing device 7. We have found this to be particularly true for cases where the conduit 8 of the mixing device is a rectangular conduit and the carrier gas FG is a low-pressure gas flow (e.g., pressures less than 12.442 kPa or less than 13 kPa, between 13 kPa and 1.0 kPa, between 13 kPa and 1.2 kPa, etc.). Surprisingly, we have found that the mixing device 7 can provide excellent mixing capabilities for large aspect ratios between 1.5 and greater than 5, and between 1.5 and 5 (e.g., between 2.0 and 4.5, or between 2.0 and 4.0, etc.). We have found that even for relatively short conduits 8 of the mixing device 7 with lengths between 12 meters and 30.5 meters, or between 15 meters and 21.5 meters, good mixing for oxidant formation is provided. Furthermore, our evaluation has revealed that a well-mixed oxidant can be formed within the conduit 8 of the mixing device 7 between 3 meters and 7 meters downstream of the injection device 7i, allowing the length L of the conduit 8 to be configured to be even shorter than such a short length L.

[0096] Such shorter-length mixing device ducts, which can have a relatively large duct aspect ratio, allow for the conversion of the mixing device 7 into different systems that can have pre-existing duct layouts without requiring extensive duct replacements. This can help reduce the costs and downtime associated with the installation of the mixing device 7, and also facilitates its integration into combustion processes or systems. This may be especially true for rectangular-shaped ducts 8.

[0097] Achieving good mixing of low-pressure carrier gas with a large amount of oxygen from oxygen source 5 in a relatively large conduit 8 of mixing device 7 (e.g., a rectangular conduit of relatively large size with an aspect ratio between 1.5 and 5 or between 2 and 4, etc.) can help allow implementations of mixing device 7 to be used in a variety of different types of combustion equipment 1 configurations (e.g., steam reformers, steam-methane reformers, boilers, furnaces, etc.). This can be particularly advantageous in cases where the mass flow rate of oxygen to be mixed into carrier gas FG to form oxidant is relatively high (e.g., more than 20% of the total flow rate of oxidant to be formed, between 20% and 30% of the total flow rate of oxidant to be formed, between 15% and 35% of the total flow rate of oxidant to be formed, etc.). For example, in cases where the oxygen to be injected is generated using flue gas as a carrier gas (FG) to form syngas as an oxidant, the amount of oxygen required to form the oxidant can be significantly higher than the amount of oxygen required for enriching ambient air, which may have the same desired oxygen concentration level. This is because the air already contains approximately 21 mol% oxygen, while the flue gas may contain only 0-2 mol% oxygen or trace amounts of oxygen before oxygen is injected from oxygen source 5. During syngas formation, the mass of oxygen required to form an oxidant with 20 to 40 mol% oxygen, 20 to 35 mol% oxygen, or 21 to 28 mol% oxygen is significantly greater. This may necessitate that the mixing device 7 be able to efficiently mix a considerable mass flow rate of oxygen into the flue gas over a short duct length, thereby providing a properly mixed oxidant for the combustion operation of the combustion device 3. It is also desirable to provide good mixing within short sections of the mixing device duct while maintaining peak oxygen concentrations at the duct walls (e.g., bottom 7b, top, sidewalls 7sw) at low values ​​or below a pre-selected maximum oxygen content level, as we have found this helps prevent damage or wear to the mixing device 7 and downstream ducts. We have found that embodiments of our mixing device 7 can surprisingly allow mass flow ratios of multiple primary fluids (e.g., oxygen injection) to carrier fluids (e.g., air or flue gas) in the range of 0.1 to 1.0. For example, we have found that embodiments of our mixing device 7 can facilitate mixing with flue gas or air mixed with flue gas carrier gas applications, where the oxygen to carrier gas mass ratio is high (e.g., at least 0.4, between 0.3 and 0.5, between 0.3 and 1.0, etc.).

[0098] Computational flow analysis was performed on different implementation schemes of the equipment used for oxidant formation. Figure 4 and Figure 5 The results from the evaluation are illustrated, in which the conduit 8 of the mixing device 7 is a rectangular conduit with a width W, a length L, and a height H. (As shown from...) Figure 4 and Figure 5 It can be seen that uniform feeding of oxygen into the carrier gas via all injection devices 7i providing the same oxygen injection rate provides mixing, resulting in peak oxygen concentrations at the conduit wall (e.g., the conduit wall, which may include the top, bottom 7b, and sidewall 7sw) and at the outlet 7o of the mixing device 7. However, biased injection provides improved results by providing better mixing and a lower peak oxygen fraction at the outlet 7o and at the conduit wall (e.g., bottom 7b, top, and sidewall 7sw), in which 20% more oxygen is injected via the injection device 7i in the central region CR compared to the injection devices in the outer regions 1OR and 2OR (which utilize the same oxygen injection rate).

[0099] Figure 6 and Figure 7 The accompanying diagram illustrates the process of generating... Figure 4 and Figure 5 The CFD results obtained from the modeling of the implementation scheme of the data mixing device 7. Figure 6 and 7 It was also shown that, compared to the outer regions (1OR and 2OR), biased injection, which provides higher oxygen injection at the central region CR, can provide superior mixing for relatively large catheter aspect ratios. For example, Figure 6 As shown, this was found to be particularly suitable for large catheter aspect ratios of 3 or greater (e.g., 3-4, 3-4.5, 3-5, 3.5-5, etc.), where each injection device in the central region CR injects oxygen at a flow rate 20% higher than that in the outer regions of the injection device. CFD results showed that biased injection, providing higher oxygen injection at the central region CR, could provide substantially better mixing results for catheter aspect ratios, for example, greater than 3.5, compared to the outer regions (1OR and 2OR). Both a high catheter aspect ratio and biased injection providing a higher oxygen injection rate at the central region CR can be used to obtain these superior mixing results compared to the outer regions (1OR and 2OR).

[0100] We also evaluated the use of a central region injection rate for an infusion device used for central region CR, where the catheter aspect ratio is greater than 3, with the oxygen flow rate for central region CR being 10% higher than the oxygen flow rate set for the external region injection rate of the infusion device used for external regions (e.g., the first external region 1OR and the second external region 2OR). Our analysis found that a substantial improvement in peak O2 content reduction can be achieved by using a 10% higher central region injection rate. Compared to a uniform injection flow rate, using a 10% higher central region injection rate for the infusion device for central region CR provided a reduction of approximately 7 mol% in peak O2 content compared to using a uniform injection flow rate for all regions (e.g., with a 10% higher central region injection rate, the peak O2 content was found to be approximately 40 mol% at a uniform flow rate, and approximately 33 mol% at a peak O2 content). Based on the evaluation conducted, we believe that center-biased oxygen injection can also provide significant improvement for catheter aspect ratios greater than 3 (e.g., catheter aspect ratios greater than 3 and up to 5, etc.), in which the central region injection rate is 5% higher than that for external region injection devices (e.g., injection devices for a first external region 1OR and a second external region 2OR).

[0101] In any case, significant and substantial improvements can be achieved by using injection rates with a center offset greater than 10%, and even greater improvements are provided for injection rates with such center offsets greater than 20%. This was found, for example, in cases where there are high catheter aspect ratios (e.g., catheter aspect ratios greater than 3 to 5 or 3.5 to 5, etc.).

[0102] The surprising result of biased injection, with at least 20% more oxygen injected into the carrier gas FG via the injection device 7i through the central region CR compared to the outer regions located on opposite sides of the central region (e.g., the first outer region 1OR and the second outer region 2OR), is further demonstrated by, as... Figure 8 The computational flow analysis shown is used to confirm this. For example, from... Figure 8 As can be seen, compared to the uniform oxygen injection flow rate shown in the top figure GrA, the biased flow of oxygen injection at the bottom 7b of the 4:1 duct aspect ratio provides excellent mixing as shown in the bottom figure of GrB, where the oxygen injection mass flow rate of the injection device 7i in the central region CR is higher than the oxygen injection mass flow rate via the side region or outer region injection devices 7i (e.g., injection devices in the first outer region 1OR and the second outer region 2OR). Figure 8As can be seen, compared to the equal flow rate scenario in the top plot GrA, the centrally biased injection scenario shown in the bottom plot GrB results in a lower peak oxygen concentration and a more uniform distribution in the oxidant. For example, the high O2 region is only present in the top plot GrA, which helps highlight this surprising difference found in the CFD analysis.

[0103] These results of improved mixing provided by biased oxygen injection in the central region CR are surprising, since a larger injection in the central region CR would have resulted in a higher O2 region in the center of catheter 8. Instead, this was not the case, and surprisingly, better mixing was found by having a higher injection rate in the central region CR.

[0104] The implementation scheme of combustion device 1 can include a method for forming an oxidant or a method for combustion using the formed oxidant. From Figure 9 Examples of implementations of such methods can be understood in the following. In the first step S1, an oxidant can be formed by mixing carrier gas FG from at least one gas source 4 and / or flue gas RGF recirculated from the combustion device 3 with oxygen from at least one oxygen source 5. The formed oxidant can be, for example, oxygen-enriched air or synthetic air as discussed above. The formed oxidant can be formed, for example, by mixing carrier gas FG from at least one gas source 4 and / or flue gas recirculated from the combustion device 3 with oxygen from at least one oxygen source via a mixing device 7. Such formation can occur via the mixing device 7, which uses biased oxygen injection to inject oxygen for mixing with the flue gas, wherein at least 20% more oxygen is injected into the central region CR of the injection device 7i compared to the outer region of the injection device on the opposite side of the central region CR (e.g., between the central region and the sidewall 7sw of the duct 8 of the mixing device). The injection can occur downstream of at least one flow regulating device 7p (e.g., a perforated plate as discussed above), and the oxidant is formed before it is discharged from the outlet 7o of the mixing device 7.

[0105] In the second step S2, the formed oxidant can be fed into the combustion chamber of the combustion device 3 as an oxidant for burning fuel in the combustion chamber to form combustion products. In the case where synthetic air is used as the oxidant, using synthetic air as the oxidant can also allow for a reduction in the formation of nitrogen oxides via combustion (e.g., as discussed above and below). Implementations of this method may also include other steps. For example, some implementations may include a third step S3 (shown in dashed lines), in which a portion of the formed flue gas (which includes combustion products formed from combustion promoted by the feed of the formed oxidant) may be discharged from the combustion device 3 for capturing carbon dioxide from the flue gas via at least one carbon capture device (e.g., carbon capture device 11). This type of carbon capture can be provided while a portion of the flue gas is also recycled back to the mixing device 7 as a recirculated flue gas stream RFG for forming synthesis air as an oxidant, as discussed above for implementations in which synthesis air is formed as an oxidant. The ratio of the flue gas fed to the carbon capture device 11 and recycled to the mixing device 7 for forming synthesis air or other oxidants can be adjusted to suit various operating conditions, which may include, for example, the CO2 content in the flue gas as discussed above. Proportional splitting may also include forming other portions of the flue gas for routed delivery to other locations (e.g., forming a third portion for emission, forming another portion for feeding into another method apparatus or industrial equipment element, etc.).

[0106] As discussed above, it was surprisingly found that the implementation of method and apparatus 1 can provide a significant reduction in NOx formation. Furthermore, the implementation can provide an improved ability to capture CO2 for providing at least one CO2 product stream 11p, which can have a high CO2 concentration (e.g., greater than 90 mol% CO2, etc., as discussed above).

[0107] Confidential testing was conducted to evaluate the implementation of our device 1 and method for reducing nitrogen oxide formation during combustion. The testing demonstrated that the implementation of our device 1 and method can provide significant NOx reduction and improved carbon capture.

[0108] In the tests conducted, an industrial air-staged non-premixed downcombustion burner with a load of 1.1 MW was used to burn a blend of two fuels: natural gas and pressure swing adsorption (PSA) exhaust gas (e.g., hydrogen). Table 1 below shows the composition of the feedstock used in this experiment: Table 1 Fuel composition used for the first set of tests natural gas 22.0 Hydrogen (H2) 25.2 CO2 50.8 N2 2.0 The fuel composition has a molecular weight of 27.25, a low calorific value (LHV) of 9,107 kJ / kg, and a theoretical air requirement of 2.8243 on a volume-to-volume (vol / vol) basis for complete combustion.

[0109] Ambient air was used as the oxidant for comparison with an implementation using synthetic air. Ambient air had typical air concentrations (e.g., 20-21 mol% oxygen, 78-79 mol% nitrogen, trace amounts of CO2, water, and Ar, etc.). The composition of the synthetic air used in the tests is shown in Table 2 below: Table 2 The composition of synthetic air used in the first set of tests CO2 35.27 Ar 1.8 O2 26.01 N2 8.32 Water (H2O) 28.60 In the experiments conducted, using air as the oxidant resulted in NOx emissions of 25 parts per million (ppm). In contrast, using synthetic air provided a 95% reduction in NOx emissions (e.g., producing 2.5 ppm of NOx).

[0110] Additional tests were conducted to evaluate the use of different fuel compositions and varying oxygen compositions in synthetic air to assess how these could affect NOx formation. With oxygen contents adjusted to 22 mol% and 28 mol%, NOx emissions from fuel combustion were found to be 2.8 mg / Nm³. 3 and 2.6 mg / Nm 3 In contrast, using air and the same fuel resulted in 65.7 mg / Nm³ of combustion from the fuel. 3 The formation of NOx. This further demonstrates that using synthetic air in the implementation of our methods and equipment can provide a NOx reduction of more than 95%.

[0111] Tests were also conducted to assess the potential impact of burner load on NOx emissions when using synthetic air as the oxidant. Our tests found that at 40% burner load, only 6.1 mg / Nm³ of NOx was generated. 3 This provides approximately 80% NOx reduction compared to ambient air used as an oxidant. For other, higher loads, NOx formation was found to be below 3 mg / Nm³. 3 For example, at 60% load, the use of synthetic air resulted in 2.6 mg / Nm³. 3 NOx formation was observed, and at 80% and 120% loads, using synthetic air as the oxidant resulted in 0.8 mg / Nm³. 3NOx formation is significantly reduced compared to ambient air (e.g., a reduction of more than 80% to more than 95% in NOx). The tests conducted also showed that using synthetic air helps provide approximately a 10% reduction in flame length compared to using ambient air as the oxidant. Our tests also showed that changing the oxygen content in the synthetic air from 22 mol% to 28 mol% had no meaningful effect on the adiabatic flame temperature or flame length and emissions.

[0112] These experimental results are quite surprising. In an oxygen-rich atmosphere with a relatively large amount of nitrogen, higher NOx emissions are expected near the flame, where temperatures may rise, compared to atmospheric combustion. Furthermore, even though the N2 in the synthesis air may be much lower than in ambient air, it is still sufficient for an O2-rich atmosphere to predict high NOx emissions near the flame, where temperatures may rise compared to atmospheric combustion. While the thermal and chemical effects of water are known to help suppress NOx formation, the results of the tests conducted indicate that NOx emissions are significantly and surprisingly reduced using synthesis air, and such significant reductions can be provided across a wide range of N2, CO2, and water compositions within the synthesis air. In fact, NOx emissions can be significantly reduced even in the absence of water or without steam injection.

[0113] Over time, the operation of the combustion unit 3 can lead to the ingress of air into the combustion unit. This may be due to wear of seals and other factors. As a result of this condition, the implementation of our equipment and method may result in a higher N2 content in the synthesis air over time, where the gas source for the synthesis air is recirculated flue gas RF from the combustion unit 3. While this may occur, it is still surprising to find that even after long periods of use, the N2 concentration of the synthesis air can be below 20 mol% after a substantially continuous period of operation, and still provides a reduction in NOx formation between 95% and 75% over the duration of operation. And as discussed above, such reduction in NOx can also provide improved carbon capture. Furthermore, NOx reduction and improved CO2 recovery can be provided without incurring the additional costs or operational risks associated with catalytic reduction (e.g., the risk of ammonia leakage, etc., as discussed above). Improved NOx reduction can be provided regardless of whether an advanced burner is used in the combustion unit 3.

[0114] Our methods, equipment, and system implementations can be adapted to different design standards. For example, it should be understood that other implementations may utilize different types of conduit arrangements, fuel storage tanks or fuel pipelines, oxygen storage tanks or oxygen production method units, combustion unit arrangements, and / or fuel types (e.g., natural gas, oil, diesel, coal, hydrogen, etc.).

[0115] It should also be understood that other modifications can be made to meet a specific set of criteria for different implementations of the equipment or method. For example, the arrangement of valves, pipes, and other conduit elements (e.g., conduit connection mechanisms, tubing, seals, valves, etc.) used to interconnect different units of the equipment for fluid communication between different components (e.g., compressors, fans, valves, conduits, etc.) can be arranged to meet a specific equipment layout design that takes into account the available area of ​​the equipment, the equipment's set dimensions, and other design factors. As another example, the flow rate, pressure, and temperature of the fluid passing through various equipment or system components can vary to accommodate different design configurations and other design criteria. As yet another example, the length L, width W, or height H of the mixing device conduit 8 can be configured for a specific application or installation. In some implementations, the conduit shape can be rectangular. However, it is anticipated that other implementations can utilize conduits of other shapes.

[0116] As yet another example, embodiments of the apparatus and method may each be configured to include process control elements located and configured to monitor and control operations (e.g., temperature and pressure sensors, flow sensors, automated process control systems having at least one workstation including a processor, non-transitory memory, and at least one transceiver for communicating with the sensor elements, valves, and controllers for providing a user interface to the automated process control system, which may operate on the workstation and / or another computer device of the apparatus, etc.). It should be understood that embodiments may utilize a distributed control system (DCS) to implement one or more processes and / or also control the operation of the apparatus or method.

[0117] As another example, specific features described individually or as part of an embodiment may be combined with other individually described features or as part of other embodiments. Therefore, elements and actions of the various embodiments described herein may be combined to provide additional embodiments. Thus, while certain exemplary embodiments of methods, apparatus, systems, and methods of manufacture and use thereof have been shown and described above, it should be clearly understood that the invention is not limited thereto, but may be embodied and practiced differently in other ways within the scope of the appended claims.

Claims

1. An apparatus for forming an oxidant, the apparatus comprising: A mixing device capable of being positioned and configured to receive a carrier gas from at least one gas source and / or flue gas recirculated from a combustion device, the mixing device also capable of being positioned and configured to receive oxygen from an oxygen source for feeding the oxygen into the carrier gas to form an oxidant for feeding into the combustion device. The mixing device includes a plurality of injection devices positioned within a conduit of the mixing device. Each injection device is positioned downstream of at least one flow regulating device, allowing the carrier gas to pass through the at least one flow regulating device before being conveyed along the injection device. The injection device is positioned and configured to inject the oxygen into the carrier gas to form the oxidant; The injection device includes a central region of the injection device; A first outer region of the injection device, located between the central region of the injection device and the first sidewall of the conduit; and a second outer region of the injection device, located between the central region of the injection device and the second sidewall of the conduit; The central region of the injection device is located between the first outer region of the injection device and the second outer region of the injection device; Each of the injection devices in the central region of the injection device is configured to inject oxygen at a certain mass flow rate into the carrier gas via the central region injection rate. Each of the injection devices in the first outer region of the injection device is configured to inject oxygen at a certain mass flow rate into the carrier gas via the outer region injection rate. Each of the injection devices in the second outer region of the injection device is configured to inject oxygen at a certain mass flow rate into the carrier gas via the injection rate of the outer region, and The injection rate in the central region is at least 10% greater than the injection rate in the outer region.

2. The apparatus of claim 1, wherein the mass flow rate of oxygen capable of being injected into the carrier gas via the central region of the injection device is between 30% and 60% of the total mass flow rate of oxygen capable of being injected into the carrier gas, the mass flow rate of oxygen capable of being injected into the carrier gas via the first outer region of the injection device is between 20% and 40% of the total mass flow rate of oxygen capable of being injected into the carrier gas, and the mass flow rate of oxygen capable of being injected into the carrier gas via the second outer region of the injection device is between 20% and 40% of the total mass flow rate of oxygen capable of being injected into the carrier gas.

3. The apparatus of claim 2, wherein the mass flow rate of oxygen that can be injected into the carrier gas from the second outer region of the injection device is equal to the mass flow rate of oxygen that can be injected into the carrier gas from the first outer region of the injection device.

4. The device according to claim 1, wherein the catheter has a catheter aspect ratio between 3.5 and 5.

5. The device according to claim 1, wherein the conduit has an aspect ratio greater than 3.

6. The device according to claim 1, wherein the device includes the at least one flow regulating device.

7. The device of claim 6, wherein the at least one flow regulating device comprises a perforated plate positioned within the conduit upstream of the injection device, the perforated plate having a thickness and a plurality of holes, each of the holes having a hole diameter; The ratio of the thickness of the perforated plate to the diameter of the hole is between 0.3 and 1.

8. The device of claim 7, wherein the perforated plate is positioned downstream of the carrier gas flow device or flow disturbance component at a distance between half the height of the conduit and three times the height of the conduit.

9. The device of claim 1, wherein the plurality of injection devices are arranged in an alternating manner within the conduit.

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