Variable premixing degree flameless combustion furnace

Abstract

This invention discloses a variable premixed flameless combustion furnace, comprising: a furnace body with an air inlet at the bottom and a flue gas outlet at the top; multiple variable premixed burners arranged at intervals in the lower part of the furnace body; a gas pipeline with its first axial end adjustablely positioned within the air pipeline, and its second axial end extending outside the air pipeline to form a fuel inlet, the gas pipeline slidingly sealing with an end cap; multiple ignition sources, each corresponding to one of the multiple variable premixed burners, for igniting the fuel at the burner outlet; and multiple blunt body assemblies, each corresponding to one of the multiple variable premixed burners, each blunt body assembly positioned between the corresponding variable premixed burner and an ignition source. The flameless combustion furnace provided by this invention is easy to operate and can achieve stable flameless combustion.

Description

Technical Field

[0001] This invention relates to the field of combustion technology, and in particular to a flameless combustion furnace with variable premixing degree. Background Technology

[0002] Energy and the environment are critical issues concerning human survival. The large-scale combustion of fossil fuels generates pollutants that seriously endanger human health; for example, NOx is a major cause of acid rain and photochemical smog. Therefore, developing a clean and efficient combustion technology is of great practical significance.

[0003] Flameless combustion is a novel combustion method conducted under high-temperature, low-oxygen conditions. Its core principle is to alter the reactant concentration and temperature distribution by diluting oxygen with flue gas during combustion, thereby achieving higher combustion efficiency and lower emissions. A key feature of flameless combustion is the formation of a delayed reaction zone. This is due to flue gas recirculation, which dilutes air and fuel, resulting in a lower degree of fuel-oxygen mixing. Within this delayed reaction zone, fuel and oxygen diffusion is relatively slow, leading to a more uniform and stable combustion process. Under high-temperature, low-oxygen conditions, the reduced reactant concentration also increases the reaction area, potentially filling the entire furnace. This makes it difficult for the flame front to remain stable, resulting in a more uniform temperature distribution within the furnace and eliminating the localized high-temperature, high-oxygen zones found in traditional combustion conditions. This reduces NOx emissions. Furthermore, the increased reaction area allows for more complete fuel combustion, further improving combustion efficiency and reducing fuel consumption and related carbon emissions. However, previous studies have shown that achieving flameless combustion typically requires ultra-high-speed nozzle velocities (≥100 m / s), and the cooling effect of fresh reactants leads to uneven temperature distribution within the furnace.

[0004] The present invention was developed to address the aforementioned problems. Summary of the Invention

[0005] The purpose of this invention is to provide a flameless combustion furnace with variable premixing degree, which can achieve flameless combustion at medium jet velocity.

[0006] Based on the above problems, the technical solution provided by the present invention is as follows:

[0007] A flameless combustion furnace with variable premixing degree, comprising:

[0008] The main body of the combustion furnace has an air inlet at the bottom and a flue gas outlet at the top;

[0009] Multiple variable premixed burners are arranged at intervals in the lower part of the combustion furnace body, the variable premixed burners comprising:

[0010] An air duct is fixed to the combustion furnace body. An air inlet pipe is provided on the outer wall of the air duct, and a burner outlet extending into the combustion furnace body is provided at the first axial end away from the air inlet pipe. The second axial end of the air duct extends outside the combustion furnace body and is provided with an end cap.

[0011] A gas pipeline, the first axial end of which is adjustablely positioned is installed in the air pipeline, and the second axial end of the gas pipeline extends to the outside of the air pipeline to form a fuel inlet. The gas pipeline is slidably sealed with the end cap.

[0012] Multiple ignition sources are respectively configured to correspond to the multiple variable premixed combustion sources and are used to ignite the fuel at the burner outlet;

[0013] Multiple blunt body components are respectively configured to correspond to the multiple variable premixed burners, with each blunt body component positioned between the corresponding variable premixed burner and the ignition source.

[0014] In some embodiments, the air duct extends at an angle to the radial direction of the combustion furnace body.

[0015] In some embodiments, the air inlet includes a plurality of air inlet pipes fixed to the main body of the combustion furnace, the plurality of air inlet pipes being installed corresponding to the plurality of variable premixed burners, and the extension direction of the air inlet pipes being arranged at an angle α to the extension direction of the air ducts.

[0016] In some of these embodiments, the number of variable premixed burners and air inlets is n, and the angle α is 180 / n.

[0017] In some embodiments, the air inlet pipe is tangentially connected to the air duct.

[0018] In some of these embodiments, the blunt body assembly includes:

[0019] A blunt slide is fixed to the main body of the combustion furnace. The blunt slide has an axial first end opening inside the main body of the combustion furnace and an axial second end covered.

[0020] A support member that slides and seals with the cover, a blunt body is fixed at the first end of the support member in the length direction, and a handle portion is formed at the second end of the support member in the length direction outside the slide of the blunt body.

[0021] In some embodiments, the inner wall of the blunt body slide is provided with a sliding support portion, and the support member is provided with a guide sleeve that matches the sliding support portion. When the guide sleeve slides along the sliding support portion to the sealing position, the blunt body is received into the blunt body slide.

[0022] In some embodiments, the combustion furnace body includes a cylindrical furnace body, a bottom plate disposed at the lower end of the furnace body, and a top cover disposed at the upper end of the furnace body.

[0023] In some embodiments, the furnace body is provided with multiple sets of measuring ports, each set of measuring ports including multiple measuring ports spaced apart along the height direction of the furnace body, and the outer end of the measuring port is provided with a detachable sealing cap.

[0024] In some embodiments, the top cover is provided with the smoke outlet, the top cover is provided with an observation window, and the outer side of the top cover is provided with a heat insulation layer.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] 1. A variable premixed burner is adopted, and the gas pipeline can slide inside the air pipeline to change the premixing of fuel and air. The outlet is equipped with a blunt body to achieve stable combustion under high-speed jet conditions.

[0027] 2. Coaxial jet combustion and partially premixed combustion can be achieved in a variable premixed burner, and rotary non-premixed combustion can also be achieved through a flameless combustion air inlet, and flameless combustion can be achieved in all three cases;

[0028] 3. The combustion furnace has a simple structure, is easy to operate, and has a stable flameless combustion state. It can still maintain stable combustion when the power and other operating conditions are changed. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. The accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is one of the structural schematic diagrams of a flameless combustion furnace with variable premixing degree according to the present invention;

[0031] Figure 2 for Figure 1 Schematic diagram of the AA section;

[0032] Figure 3 for Figure 1 Schematic diagram of the BB cross section;

[0033] Figure 4 This is a schematic diagram of the structure of the variable premixed burner in an embodiment of the present invention;

[0034] Figure 5 for Figure 4 Schematic diagram of the CC section;

[0035] Figure 6 This is a schematic diagram of the structure of the blunt body component in an embodiment of the present invention;

[0036] in:

[0037] 1. Combustion furnace body; 1-1. Furnace body; 1-2. Bottom plate; 1-3. Top cover; 1-3a. Smoke outlet; 1-3b. Observation window;

[0038] 2. Variable premixed burner; 2-1. Air duct; 2-2. Air inlet duct; 2-3. Gas duct; 2-3a. Fuel inlet; 2-4. End cap;

[0039] 3. Ignition source; 3-1. Sensing needle; 3-2. Ignition needle;

[0040] 4. Blunt body assembly; 4-1. Blunt body slide; 4-2. Support component; 4-3. Blunt body; 4-4. Sliding support part; 4-5. Guide sleeve; 4-6. Cover; 4-7. Sealing plate; 4-8. Handle part;

[0041] 5. Air inlet pipe;

[0042] 6. Measuring port; 6-1. Sealing cap. Detailed Implementation

[0043] The above-described solution will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. The implementation conditions used in the embodiments may be further adjusted according to the conditions of specific manufacturers, and the implementation conditions not specified are generally those in routine experiments.

[0044] See Figures 1 to 3 The diagram below is a structural schematic of an embodiment of the present invention. A flameless combustion furnace with variable premixing is provided, including a combustion furnace body 1, multiple variable premixing burners 2, multiple ignition sources 3, and multiple blunt body components 4.

[0045] The number of ignition sources 3 and blunt body components 4 corresponds to the number of variable premixed burners 2. In this example, the number of variable premixed burners 2 is set to two. It should be understood that in other embodiments, other numbers of variable premixed burners 2 can be set as needed, and the present invention does not impose any limitations.

[0046] The main body 1 of the combustion furnace includes a cylindrical furnace body 1-1, a bottom plate 1-2 located at the lower end of the furnace body 1-1, and a top cover 1-3 located at the upper end of the furnace body 1-1. The top cover 1-3 has a flue gas outlet 1-3a for exhausting flue gas, and an observation window 1-3b for observing the combustion process inside the furnace. The diameter of the observation window 1-3b is 40mm to 200mm, and the diameter of the flue gas outlet 1-3a is 1 / 10 to 1 / 5 of the diameter of the furnace body 1-1. The top cover 1-3 is hinged to the furnace body 1-1 for easy opening. A heat insulation layer is provided on the outer sides of the top cover 1-3, the furnace body 1-1, and the bottom plate 1-2 to provide heat insulation and improve safety.

[0047] To facilitate monitoring of combustion within the furnace, multiple sets of measuring ports 6 are provided on the furnace body 1-1. In this example, two sets of measuring ports 6 are provided, arranged at ninety degrees on the furnace body 1-1. Each set of measuring ports 6 includes multiple measuring ports 6 spaced apart along the height direction of the furnace body 1-1. The spacing between two adjacent measuring ports 6 can be 10mm-200mm. A sealing cover 6-1 can be detachably installed at the outer end of the measuring port 6 for sealing. During measurement, the sealing cover 6-1 is removed to monitor parameters such as temperature and combustion components inside the furnace. When not measuring, the measuring port 6 is sealed.

[0048] Two variable premixed burners 2 are arranged at intervals in the lower part of the furnace body 1-1, such as... Figure 4 As shown, the variable premixed burner 2 includes an air duct 2-1 fixed to the furnace body 1-1 and a gas duct 2-3 passing through the air duct 2-1. An air inlet duct 2-2 is provided on the outer wall of the air duct 2-1. At the first axial end of the air duct 2-1 away from the air inlet duct 2-2, a burner outlet extending into the furnace body 1 is provided. The burner outlet is tangent to the inner wall of the furnace body 1-1 to prevent overheating and burnout of the duct. The second axial end of the air duct 2-1 extends outside the furnace body 1 and is provided with an end cap 2-4. Wherein, as... Figure 5 As shown, the air inlet pipe 2-2 is tangentially connected to the air pipe 2-1 so that air can enter tangentially from the air pipe 2-1, forming an air vortex, increasing the mixing degree of air and fuel, and enabling stable combustion during the preheating stage.

[0049] The gas pipeline 2-3 and the end cap 2-4 are slidably sealed together. The first axial end of the gas pipeline 2-4 is adjustablely positioned in the air pipeline 2-1. The second axial end of the gas pipeline 2-3 extends to the outside of the air pipeline 2-1 to form a fuel inlet 2-3a.

[0050] In this example, the extension direction of the air duct 2-1 is arranged at an angle to the radial direction of the furnace body 1-1. This angle can be set from 0° to 80° depending on the construction conditions.

[0051] To ensure more uniform and dispersed air entering the furnace body 1-1 and to slow down the reaction time, the air inlet includes multiple air inlet pipes 5 fixed to the furnace body 1-1. Each air inlet pipe 5 is installed corresponding to a variable premixed burner 2, and the extension direction of the air inlet pipe 5 forms an angle α with the extension direction of the air duct 2-1. If the number of variable premixed burners 2 and air inlet pipes 5 is n, then the angle α is 180 / n. In this example, n is 2, so the angle α is 90 degrees. An internally threaded mounting head is provided at the head of the air inlet pipe 5 near the interior of the furnace body 1-1. Different nozzles can be detached and fixed on the internally threaded mounting head to obtain different air inlet velocities.

[0052] Two ignition sources 3 are respectively arranged with two variable premixed burners 2 to ignite the fuel at the burner outlet. The ignition source 3 adopts the structure in the prior art, including a sensing needle 3-1 and an ignition needle 3-2. When the sensing needle 3-1 senses the fuel, the ignition needle 3-2 ignites and burns it.

[0053] like Figure 6 As shown, the blunt body assembly 4 is disposed between the corresponding variable premixed burner 2 and the ignition source 3 for stable combustion. The blunt body assembly 4 includes a blunt body slide 4-1 fixed on the furnace body 1-1, a support member 4-2 passing through the blunt body slide 4-1, and a blunt body 4-3 fixed on the support member 4-2. The blunt body slide 4-1 has an axial first end opening located inside the combustion furnace body 1, and a cover 4-6 is provided at the axial second end. The support member 4-2 and the cover 4-6 are slidably sealed together. A sealing piece 4-7 can also be provided at the outer end of the cover 4-6 to achieve a sealing effect. The blunt body 4-3 is fixed at the first end of the support member 4-2 in the length direction and is 5mm to 100mm away from the outlet of the variable premixed burner. The second end of the support member 4-2 in the length direction extends to the outside of the blunt body slide 4-1 to form a handle part 4-8. By pulling the support member 4-2 through the handle part 4-8, the blunt body 4-3 can be accommodated in the blunt body slide 4-1.

[0054] To improve the stability of the movement of the blunt body 4-3, a sliding support part 4-4 is provided on the inner wall of the blunt body slide 4-1. A guide sleeve 4-5 matching the sliding support part 4-4 is provided on the support member 4-2. Through the sliding engagement of the guide sleeve 4-5 and the sliding support part 4-4, the extension length of the blunt body 4-3 can be adjusted to meet the requirements of stable combustion. When the guide sleeve 4-5 slides along the sliding support part 4-4 to the capping position 4-6, the blunt body 4-3 can be accommodated in the blunt body slide 4-1.

[0055] The working principle described above is as follows:

[0056] The combustion process in the combustion furnace is divided into two stages: conventional combustion and flameless combustion. In the conventional combustion stage, air and fuel gas are premixed in the variable premixed burner 2 and injected at a speed of 10-100 m / s. After passing through the blunt body 4-3, they are ignited for conventional combustion, heating the furnace. Depending on the fuel, when the furnace is heated to 600℃-1200℃, flameless combustion can be achieved in two ways: First, the blunt body 4-3 is removed, so that there is no deceleration at the outlet of the variable premixed burner 2, and the flame cannot exist stably, thus achieving flameless combustion; Second, the air in the variable premixed burner 2 is shut off, and air is supplied by the air inlet pipe 5, thereby achieving flameless combustion.

[0057] In summary, this combustion furnace can achieve coaxial jet combustion and partially premixed combustion in a variable premixed burner, and can also achieve rotary non-premixed combustion through an air inlet pipe. It has a simple structure and stable flameless combustion state.

[0058] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A flameless combustion furnace with variable premixing degree, characterized in that, include: The main body of the combustion furnace has an air inlet at the bottom and a flue gas outlet at the top; Multiple variable premixed burners are arranged at intervals in the lower part of the combustion furnace body, the variable premixed burners comprising: An air duct is fixed to the main body of the combustion furnace. An air inlet pipe is provided on the outer wall of the air duct, and a burner outlet extending into the main body of the combustion furnace is provided at the first axial end away from the air inlet pipe. The second axial end of the air duct extends out of the main body of the combustion furnace and is provided with an end cap. A gas pipeline, the first axial end of which is adjustablely positioned is installed in the air pipeline, and the second axial end of the gas pipeline extends to the outside of the air pipeline to form a fuel inlet. The gas pipeline is slidably sealed with the end cap. Multiple ignition sources are respectively configured to correspond to the multiple variable premixed combustion sources and are used to ignite the fuel at the burner outlet; Multiple blunt body components are respectively disposed corresponding to the multiple variable premixed burners, and each blunt body component is disposed between the corresponding variable premixed burner and the ignition source; The blunt body assembly includes: A blunt slide is fixed to the main body of the combustion furnace. The blunt slide has an axial first end opening inside the main body of the combustion furnace and an axial second end covered. A support member that slides and seals with the cover, a blunt body is fixed at the first end of the support member in the length direction, and a handle portion is formed at the second end of the support member in the length direction outside the slide of the blunt body. The inner wall of the blunt body slide is provided with a sliding support part, and the support member is provided with a guide sleeve that matches the sliding support part. When the guide sleeve slides along the sliding support part to the sealing position, the blunt body is received into the blunt body slide.

2. The variable premixed degree flameless combustion furnace according to claim 1, characterized in that: The air duct extends at an angle to the radial direction of the combustion furnace body.

3. The variable premixed degree flameless combustion furnace according to claim 2, characterized in that: The air inlet includes multiple air inlet pipes fixed on the main body of the combustion furnace. The multiple air inlet pipes are installed corresponding to the multiple variable premixed burners, and the extension direction of the air inlet pipes is arranged at an angle α with the extension direction of the air duct.

4. The variable premixed degree flameless combustion furnace according to claim 3, characterized in that: The number of variable premixed burners and air inlets is n, and the angle α is 180 / n.

5. The variable premixed degree flameless combustion furnace according to claim 1, characterized in that: The air inlet pipe is tangentially connected to the air duct.

6. The variable premixed degree flameless combustion furnace according to claim 1, characterized in that: The main body of the combustion furnace includes a cylindrical furnace body, a bottom plate disposed at the lower end of the furnace body, and a top cover disposed at the upper end of the furnace body.

7. The variable premixed degree flameless combustion furnace according to claim 6, characterized in that: The furnace body is provided with multiple sets of measuring ports, each set of measuring ports including multiple measuring ports arranged at intervals along the height direction of the furnace body, and the outer end of the measuring port is provided with a sealing cap.

8. The variable premixed degree flameless combustion furnace according to claim 6, characterized in that: The top cover is provided with the smoke outlet and an observation window. The outer side of the combustion furnace body is provided with a heat insulation layer.

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