An ammonia fuel homogeneous fluidized combustion device and method

Abstract

The application provides an ammonia fuel uniform fluidization combustion device and method, and aims at solving the technical problems of low ammonia gas combustion efficiency and difficulty in igniting ammonia gas by electric spark without catalyst in traditional ammonia gas combustion devices. The ammonia fuel uniform fluidization combustion device comprises a combustion cavity, a gas premixing chamber, two bed layer plates, metal small balls and a heating device; the two bed layer plates are arranged on one side close to a gas input port and one side close to a gas output port in the combustion cavity respectively, and the outer side walls of the two bed layer plates are connected with the inner side walls of the combustion cavity; the metal small balls are movably arranged on the bed layer plate on the side close to the gas input port; a plurality of small holes are formed in the two bed layer plates; the heating device comprises a control module, an inductor coil and an alternating current power supply; the inductor coil is wound on the outer side wall of the combustion cavity, and is used for heating the metal small balls to a temperature required for ammonia gas combustion through electromagnetic induction.

Description

Technical Field

[0001] This invention relates to combustion apparatus, and more particularly to an apparatus and method for homogeneous fluidized bed combustion of ammonia fuel. Background Technology

[0002] Ammonia, as a new type of green energy, has advantages such as zero carbon emissions from combustion, high energy density, and ease of storage and transportation. The combustion and utilization of ammonia is conducive to expanding the proportion of new energy consumption and promoting the achievement of dual-carbon goals.

[0003] Currently, the application of ammonia combustion faces certain difficulties, mainly due to the following two reasons: First, the ignition method of combustion devices typically uses electric spark ignition, which utilizes the energy generated by an electric arc discharge to ignite the combustible ammonia mixture for rapid combustion. However, because ammonia requires a high temperature to ignite, a catalyst is usually needed. Without a catalyst, the energy of an electric spark is insufficient to ignite ammonia. Second, ammonia combustion is unstable and suffers from incomplete combustion. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems of the difficulty in igniting ammonia with the energy of an electric spark when there is no catalyst and the low combustion efficiency of ammonia in traditional ammonia combustion devices, and to provide a uniform fluidized bed combustion device and method for ammonia fuel.

[0005] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0006] A uniform fluidized bed combustion device for ammonia fuel includes a combustion chamber and a gas premixing chamber. The combustion chamber has a gas inlet port at its lower end and a gas outlet port at its upper end. The outlet port of the gas premixing chamber is connected to the gas inlet port of the combustion chamber to deliver a uniformly mixed air and ammonia into the combustion chamber. Its special feature is that it also includes two bed plates, multiple metal balls, and a heating device.

[0007] The two bed plates are respectively disposed in the combustion chamber on one side near the gas inlet port and the other side near the gas outlet port, and the outer sidewalls of the two bed plates are connected to the inner sidewall of the combustion chamber.

[0008] The metal spheres are movably mounted on the bed plate near the gas input port.

[0009] Both of the bed plates are provided with a plurality of small holes, the width of the short side or the diameter of the small holes being less than the minimum radial length of the metal ball;

[0010] The heating device includes a control module, an inductor coil, and an AC power supply;

[0011] The inductor coil is wound on the outer wall of the combustion chamber. One end of the inductor coil is connected to the phase line of the AC power supply, and the other end is connected to the neutral line of the AC power supply. This is used to enable the inductor coil to heat the metal ball to the temperature required for ammonia combustion through electromagnetic induction.

[0012] The output of the control module is electrically connected to the AC power supply and is used to control the start and stop of the AC power supply.

[0013] Furthermore, the heating device also includes a temperature sensor;

[0014] The temperature sensor is used to measure the real-time temperature of the metal ball;

[0015] The input terminal of the control module is connected to the output terminal of the temperature sensor, and is used to control the start and stop of the AC power supply according to the real-time temperature of the metal ball, so as to achieve temperature control.

[0016] Furthermore, it also includes a heat insulation layer installed on the outer wall of the combustion chamber;

[0017] The inductor coil is wound on the outer wall of the insulation layer.

[0018] Furthermore, it also includes an insulating housing;

[0019] The insulating housing is sealed on the outside of the inductor coil, and its upper and lower ends are respectively connected to the outer wall of the combustion chamber.

[0020] Furthermore, the metal spheres are configured as hollow structures;

[0021] The metal spheres are made of silicon steel or iron.

[0022] Furthermore, the metal sphere comprises a core and a metal coating covering the outer side of the core;

[0023] The core is made of quartz glass;

[0024] The metal coating is made of silicon steel or iron.

[0025] Furthermore, the metal sphere is spherical.

[0026] Furthermore, in the two bed plates, the outer wall of the bed plate near the gas output port is fixedly connected to the inner wall of the combustion chamber, while the outer wall of the bed plate near the gas input port is detachably connected to the inner wall of the combustion chamber; or, the outer walls of both bed plates are detachably connected to the inner wall of the combustion chamber.

[0027] Meanwhile, the present invention also provides a method for homogeneous fluidized bed combustion of ammonia fuel, which is characterized by including the following steps:

[0028] 1) Construct the above-mentioned ammonia fuel homogeneous fluidized bed combustion device;

[0029] 2. Connect the AC power supply to allow AC current to flow through the inductor coil, forming an alternating electromagnetic field. This alternating electromagnetic field heats the metal spheres inside the combustion chamber.

[0030] 3】When the metal balls are heated to the ignition temperature of the ammonia fuel, the premixed ammonia fuel is evenly distributed into the combustion chamber through the bed plate. The ammonia fuel entering the combustion chamber will drive the metal balls to move in a fluidized state between the two bed plates, so that the ammonia fuel and the metal balls that have reached the ignition temperature of the ammonia fuel can fully contact each other and exchange heat, thereby igniting the ammonia fuel.

[0031] Furthermore, step 3 specifically involves:

[0032] The temperature of the metal spheres is measured by a temperature sensor. When the metal spheres are heated to the ignition temperature of the ammonia fuel, the premixed ammonia fuel is evenly distributed into the combustion chamber through the bed plates. The ammonia fuel entering the combustion chamber causes the metal spheres to move in a fluidized state between the two bed plates, allowing the ammonia fuel to fully contact the metal spheres that have reached the ignition temperature of the ammonia fuel and exchange heat, thereby igniting the ammonia fuel. After the ammonia fuel is ignited, the temperature sensor measures the temperature of the metal spheres in real time. The control module controls the start and stop of the AC power supply based on the real-time temperature of the metal spheres to keep the temperature of the metal spheres within the set threshold, ensuring that the ammonia fuel is fully combusted in the combustion chamber.

[0033] The advantages of this invention compared to the prior art are as follows:

[0034] 1. This invention provides an ammonia fuel homogeneous fluidized bed combustion device that heats a metal ball to the temperature required for ammonia combustion through electromagnetic induction formed by an inductor coil and an AC power supply. This overcomes the problem of ammonia fuel being difficult to ignite without a catalyst, achieving zero carbon emissions throughout the process. Furthermore, utilizing the electromagnetic induction heating principle, the reaction temperature and process are easily controlled, which is beneficial for controlling thermal NOx. x It is conducive to the formation of pollutants.

[0035] 2. The ammonia fuel uniform fluidized combustion device provided by the present invention exchanges heat between heated metal balls and ammonia fuel. The ammonia fuel entering the combustion chamber will drive the metal balls on the bed plate to fluidize, so that the ammonia fuel and the metal balls are in more complete contact, shortening the heating time of ammonia fuel and increasing the heat exchange area, effectively ensuring the full, continuous and stable combustion of ammonia fuel, and improving energy utilization and combustion thermal efficiency.

[0036] 3. The ammonia fuel uniform fluidized combustion device provided by the present invention has an open structure in the premixing chamber and the bed plate that facilitates the uniform distribution and combustion of gas in the combustion chamber, which helps the ammonia fuel to react completely in the combustion chamber and improves the combustion efficiency of the ammonia fuel.

[0037] 4. The ammonia fuel uniform fluidized combustion device provided by the present invention, when the ammonia fuel is ignited, will drive the metal balls to roll up and down between the upper and lower bed plates, which will further increase the heat exchange area and improve the combustion efficiency.

[0038] 5. The ammonia fuel uniform fluidized bed combustion device provided by this invention allows the temperature of the metal spheres to be controlled via electromagnetic induction heating power, which is beneficial for controlling the combustion temperature of ammonia and reducing thermal NO. x Pollutant emissions.

[0039] 6. The ammonia fuel uniform fluidized combustion device provided by the present invention can obtain the real-time temperature of the metal ball through a temperature sensor, so as to achieve precise temperature control and ignition.

[0040] 7. The ammonia fuel uniform fluidized combustion device provided by the present invention has an insulation layer on the outer wall of the combustion chamber, which can effectively keep the metal ball in the combustion chamber warm, and an insulation layer is arranged on the outer side of the coil to ensure that the induction heating is carried out normally.

[0041] 8. The present invention provides a method for uniform fluidized combustion of ammonia fuel, which can ignite ammonia fuel without the use of a catalyst, and the steps are particularly simple and the operation is very convenient. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of an embodiment of an ammonia fuel homogeneous fluidized combustion device according to the present invention;

[0043] Figure 2 for Figure 1 A sectional view;

[0044] Figure 3 This is a schematic diagram of the bed plate structure in an embodiment of an ammonia fuel homogeneous fluidized combustion device of the present invention.

[0045] The specific labeling in the attached diagram is as follows:

[0046] 1-Gas premixing chamber, 101-Air inlet, 102-Ammonia inlet; 2-Combustion chamber, 201-Gas output port; 3-Bed plate, 301-Small hole; 4-Metal ball; 5-Insulation layer; 6-Inductor coil; 7-AC power supply; 8-Insulating shell. Detailed Implementation

[0047] To make the advantages and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] A homogeneous fluidized bed combustion device for ammonia fuel, such as Figure 1 , Figure 2 As shown, it includes a combustion chamber 2, a gas premixing chamber 1, two bed plates 3, multiple metal balls 4, and a heating device.

[0049] The lower end of the gas premixing chamber 1 has an air inlet 101 and an ammonia inlet 102 for respectively introducing air and ammonia, and for uniformly mixing the introduced air and ammonia. In actual production, ammonia is usually stored in a high-pressure storage device. Because the gas pressure inside the gas premixing chamber 1 is relatively low, after opening the pressure relief valve of the high-pressure storage device, ammonia can spontaneously enter the gas premixing chamber 1 through the delivery pipeline; the ammonia flow rate is determined according to the actual engineering application scale and is controlled by a flow meter. Air is usually delivered into the gas premixing chamber 1 by a fan, and the air flow rate is determined according to the equivalence ratio and is adjusted by the fan's operating frequency.

[0050] The lower end of the combustion chamber 2 has a gas inlet port, and the outlet port of the gas premixing chamber 1 is connected to the gas inlet port of the combustion chamber 2 to introduce a uniformly mixed air and ammonia into the combustion chamber 2. The upper end of the combustion chamber 2 has a gas outlet port 201 to discharge the high-temperature flue gas generated by combustion into subsequent processes, such as in the application of steam turbines. The high-temperature flue gas generated by combustion is passed into the steam turbine to perform work, driving the generator to work and converting thermal and kinetic energy into electrical energy.

[0051] Two bed plates 3 are respectively disposed within the combustion chamber 2 on one side near the gas inlet port and the other side near the gas outlet port 201, and the outer walls of both bed plates 3 are connected to the inner wall of the combustion chamber 2. In this embodiment, the outer wall of the bed plate 3 near the gas outlet port 201 is fixedly connected to the inner wall of the combustion chamber 2, while the outer wall of the bed plate 3 near the gas inlet port is detachably connected to the inner wall of the combustion chamber 2, for example, by a threaded connection. In other embodiments of the present invention, the outer walls of both bed plates 3 can be detachably connected to the inner wall of the combustion chamber 2.

[0052] Both bed plates 3 have multiple small holes 301 to ensure that the airflow is evenly distributed into the combustion chamber. The specific structure is as follows: Figure 3As shown. The metal ball 4 is movably mounted on the bed plate 3 near the gas inlet port. To ensure that the bed plate 3 can properly support the metal ball 4, the short side width or diameter of the small hole 301 should be less than the minimum radial length of the metal ball 4. When ammonia fuel enters the combustion chamber 2 and drives the metal ball to fluidize, the bed plate 3 near the gas outlet port 201 will restrict the metal ball between the two bed plates 3 to prevent the metal ball 4 from flowing out of the combustion chamber 2 with the gas flow.

[0053] To reduce the mass of the metal sphere 4 and improve its fluidization with ammonia fuel, the metal sphere 4 is preferably designed as a hollow structure. Simultaneously, the metal sphere 4 should be made of a material with good magnetic and thermal conductivity, such as silicon steel or iron, to achieve superior fluidization characteristics and gas-solid heat exchange. In other embodiments of the invention, the metal sphere 4 can also be configured as a two-layer structure, consisting of a core and a metal coating covering the outside of the core. The core is made of a material with low density and certain heat resistance to reduce the sphere's mass, such as quartz glass, while the metal coating on the outside of the core is made of a material with good magnetic and thermal conductivity, such as silicon steel or iron.

[0054] The metal sphere 4 can be of any shape, but in this embodiment, it is preferably circular. The size range of the metal sphere 4 is determined based on the design gas velocity of the combustion device, the diameter of the combustion chamber, and the density of the sphere in the actual application.

[0055] The heating device includes a control module, an inductor coil 6, an AC power supply 7, and an insulating housing 8.

[0056] Preferably, in this embodiment, a heat insulation layer 5 is provided on the outer wall of the combustion chamber 2, and an inductor coil 6 is wound on the outer wall of the heat insulation layer 5. At the same time, one end of the inductor coil 6 is connected to the phase line of the AC power supply 7, and the other end is connected to the neutral line of the AC power supply 7, so as to provide AC power to the inductor coil 6 through the AC power supply 7, generate electromagnetic induction eddy current effect to form an alternating electromagnetic field, and then heat the metal ball 4 in the combustion chamber 2 to the temperature required for ammonia combustion through the alternating electromagnetic field.

[0057] Meanwhile, since ammonia fuel is difficult to sustain combustion, the control module needs to control the heating device to continuously heat the metal ball 4 so that the temperature of the metal ball 4 is always maintained at the ignition temperature of the ammonia fuel.

[0058] This embodiment also includes a temperature sensor for measuring the real-time temperature of the metal ball 4. The input terminal of the control module is connected to the output terminal of the temperature sensor, and its output terminal is electrically connected to the AC power supply 7. The control module controls the start and stop of the AC power supply 7 based on the real-time temperature of the metal ball 4, thereby achieving temperature control.

[0059] The insulating housing 8 is sealed on the outside of the inductor coil 6, and its upper and lower ends are respectively connected to the outer wall of the combustion chamber 2 to provide insulation protection for the inductor coil 6.

[0060] The working principle of the ammonia fuel uniform fluidized bed combustion device of the present invention is as follows: When the AC power supply 7 is turned on, AC current is passed through the inductor coil 6 to form an alternating electromagnetic field. This alternating electromagnetic field heats the metal balls in the combustion chamber 2. When the temperature inside the chamber reaches the ignition temperature of the ammonia fuel, air and ammonia are sent into the gas premixing chamber 1 for thorough mixing. The uniformly mixed ammonia fuel then flows upward through the bed plate 3 and is evenly distributed into the combustion chamber 2. The ammonia fuel entering the combustion chamber 2 causes the metal balls on the bed plate 3 to move in a fluidized state between the two bed plates 3, allowing the ammonia fuel to fully contact and exchange heat with the metal balls that have reached the ignition temperature of the ammonia fuel, thereby igniting the ammonia fuel. When the ammonia fuel is ignited, it causes the metal balls 4 to tumble up and down between adjacent upper and lower bed plates 3, further increasing the heat exchange area and allowing more ammonia fuel to be ignited, achieving complete combustion and effectively improving combustion efficiency.

[0061] The present invention provides a uniform fluidized bed combustion device for ammonia fuel. On the one hand, the device heats the metal balls to the temperature required for ammonia combustion through electromagnetic induction formed by the inductor coil 6 and the AC power supply 7, overcoming the problem that ammonia fuel is difficult to ignite in the absence of a catalyst. On the other hand, the upper and lower bed plates 3 restrict the fluidized movement of the metal balls in the combustion chamber 2, effectively ensuring the full, continuous and stable combustion of ammonia fuel, reflecting the uniformity of the fluidized bed burner, and improving energy utilization and combustion thermal efficiency.

[0062] The present invention also provides a method for homogeneous fluidized bed combustion of ammonia fuel, specifically including the following steps:

[0063] 1. Construct the above-mentioned ammonia fuel homogeneous fluidized combustion device.

[0064] 2】Connect the AC power supply 7 to allow AC power to flow into the inductor coil 6 to form an alternating electromagnetic field, which heats the metal ball 4 in the combustion chamber 2.

[0065] 3. When the metal ball 4 is heated to the ignition temperature of the ammonia fuel, the premixed ammonia fuel is evenly distributed into the combustion chamber 2 via the bed plate 3. In this embodiment, the temperature of the metal ball 4 is used as feedback from the temperature sensor to determine whether it has been heated to the ignition temperature of the ammonia fuel. In other embodiments of the present invention, the time for the metal ball 4 to be heated to the ignition temperature can also be calculated based on the electromagnetic induction heating power. When the preset time is reached, the metal ball 4 is considered to have been heated to the ignition temperature of the ammonia fuel.

[0066] At this time, the ammonia fuel entering the combustion chamber 2 will cause the metal balls to move in a fluidized state between the two bed plates 3, so that the ammonia fuel and the metal balls 4 that have reached the ignition temperature of ammonia fuel can fully contact each other and exchange heat, thereby igniting the ammonia fuel.

[0067] After the ammonia fuel is ignited, the temperature sensor measures the temperature of the metal ball 4 in real time and transmits it to the control module. The control module uses a PID controller to control the start and stop of the AC power supply 7 based on the real-time temperature of the metal ball 4, ensuring that the temperature of the metal ball 4 remains within a set threshold and that the ammonia fuel is fully combusted in the combustion chamber 2. Specifically, when the temperature of the metal ball 4 exceeds the highest value of the set threshold, the control module controls the AC power supply 7 to turn off, stopping the heating of the metal ball 4 in the combustion chamber 2 via the alternating electromagnetic field. When the temperature of the metal ball 4 falls below the lowest value of the set threshold, the control module controls the AC power supply 7 to turn on, heating the metal ball 4 in the combustion chamber 2 via the alternating electromagnetic field.

[0068] The above description is only used to illustrate the technical solutions of the present invention, and is not intended to limit them. For those skilled in the art, modifications can be made to the specific technical solutions described in the above embodiments, or equivalent substitutions can be made to some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions protected by the present invention.

Claims

1. A uniform fluidized bed combustion device for ammonia fuel, comprising a combustion chamber (2) and a gas premixing chamber (1); a gas input port is provided at the lower end of the combustion chamber (2), and a gas output port (201) is provided at the upper end of the combustion chamber (2); the output port of the gas premixing chamber (1) is connected to the gas input port of the combustion chamber (2) for sending uniformly mixed air and ammonia into the combustion chamber (2). Its features are: It also includes two bed plates (3), multiple metal balls (4), a heating device, an insulating shell (8), and a heat insulation layer (5) set on the outer wall of the combustion chamber (2); The two bed plates (3) are respectively disposed in the combustion chamber (2) on the side near the gas input port and the side near the gas output port (201), and the outer sidewalls of the two bed plates (3) are connected to the inner sidewall of the combustion chamber (2); The metal ball (4) is movably disposed on the bed plate (3) on the side near the gas input port; Multiple small holes (301) are provided on both bed plates (3), and the short side width or diameter of the small holes (301) is smaller than the minimum radial length of the metal ball (4); The heating device includes a control module, an inductor coil (6), an AC power supply (7), and a temperature sensor; The inductor coil (6) is wound on the outer wall of the insulation layer (5). One end of the inductor coil (6) is connected to the phase line of the AC power supply (7), and the other end is connected to the neutral line of the AC power supply (7). The inductor coil (6) is used to heat the metal ball (4) to the temperature required for ammonia combustion through electromagnetic induction. The temperature sensor is used to measure the real-time temperature of the metal ball (4); The input terminal of the control module is connected to the output terminal of the temperature sensor, and the output terminal of the control module is electrically connected to the AC power supply (7) to control the start and stop of the AC power supply (7) according to the real-time temperature of the metal ball (4). The insulating shell (8) is sealed on the outside of the inductor coil (6), and its upper and lower ends are respectively connected to the outer wall of the combustion chamber (2).

2. The ammonia fuel homogeneous fluidized bed combustion device according to claim 1, characterized in that: The metal sphere (4) is configured as a hollow structure; The metal ball (4) is made of silicon steel or iron.

3. The ammonia fuel homogeneous fluidized bed combustion device according to claim 1 or 2, characterized in that: The metal sphere (4) includes a core and a metal coating covering the outside of the core; The core is made of quartz glass; The metal coating is made of silicon steel or iron.

4. The ammonia fuel homogeneous fluidized bed combustion device according to claim 1, characterized in that: The metal sphere (4) is circular.

5. The ammonia fuel homogeneous fluidized bed combustion device according to claim 1, characterized in that: In the two bed plates (3), the outer wall of the bed plate (3) near the gas output port (201) is fixedly connected to the inner wall of the combustion chamber (2), and the outer wall of the bed plate (3) near the gas input port is detachably connected to the inner wall of the combustion chamber (2); or, the outer walls of both bed plates (3) are detachably connected to the inner wall of the combustion chamber (2).

6. A method for homogeneous fluidized bed combustion of ammonia fuel, characterized in that, Includes the following steps: 1) Construct a uniform fluidized bed combustion device for ammonia fuel as described in any one of claims 1-5; 2】Connect the AC power supply (7) to allow AC power to flow into the inductor coil (6) to form an alternating electromagnetic field, which heats the metal ball (4) in the combustion chamber (2). 3】When the metal ball (4) is heated to the ignition temperature of the ammonia fuel, the premixed ammonia fuel is evenly distributed into the combustion chamber (2) through the bed plate (3). The ammonia fuel entering the combustion chamber (2) will cause the metal ball to move in a fluidized state between the two bed plates (3), so that the ammonia fuel and the metal ball (4) that has reached the ignition temperature of the ammonia fuel can fully contact each other and exchange heat, thereby igniting the ammonia fuel.

7. The method for homogeneous fluidized bed combustion of ammonia fuel according to claim 6, characterized in that, Step 3: Specifically, it is as follows: The temperature of the metal ball (4) is measured by a temperature sensor. When the metal ball (4) is heated to the ignition temperature of the ammonia fuel, the premixed ammonia fuel is evenly distributed into the combustion chamber (2) through the bed plate (3). The ammonia fuel entering the combustion chamber (2) will cause the metal ball to move fluidized between the two bed plates (3), so that the ammonia fuel and the metal ball (4) that has reached the ignition temperature of the ammonia fuel can fully contact each other and exchange heat, thereby igniting the ammonia fuel. After the ammonia fuel is ignited, the temperature sensor measures the temperature of the metal ball (4) in real time and transmits it to the control module. The control module controls the start and stop of the AC power supply (7) through the real-time temperature of the metal ball (4) so ​​that the temperature of the metal ball (4) is within the set threshold, ensuring that the ammonia fuel is fully burned in the combustion chamber (2).

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