Ultra-low nitrogen combustion system and method

Abstract

The present invention discloses an ultra-low nitrogen combustion system and method, including: a burner, the burner includes a fan, an air supply channel, a main gas system and an auxiliary gas system, and the air supply channel includes an inner air duct and an outer air duct, and the outer air duct is sleeved on the outside of the inner air duct, and the air outlet of the fan is screwed and fixed with a necking interface through a flange; a main gas system, the main gas system includes an air collection bag, multiple branch pipes and multiple nozzles, and the air collection bag and the nozzles are connected through branch pipes. The ultra-low nitrogen combustion system and method use oxygen in the hot flue gas after peripheral lean premixed combustion to complete subsequent combustion. Since the gas is relatively excessive, it is rich gas combustion, and the combustion temperature is low, which is conducive to suppressing NOx generation, and since the hot flue gas participates in its combustion, NOx generation can be further reduced; reduce the factory's NOx processing capacity, and protect the environment at the same time.

Description

Technical Field

[0001] The present invention relates to the field of industrial environmental protection, and in particular to an ultra-low nitrogen combustion system and method. Background Art

[0002] The national environmental protection policy is becoming increasingly stringent, and the requirements for boiler nitrogen oxide emissions are also getting higher and higher. For gas combustion, the generation mechanism of NOx is mainly thermal, that is, when the flame temperature is high enough, it will destroy the N2 covalent bond to obtain free N ions, which combine with oxygen atoms to form NOx. During the boiler combustion process, a large amount of NOx will be generated. The treatment of NOx will increase the cost of the factory, and direct emission into the air will pollute the environment. Summary of the invention

[0003] In order to fill the gap in the market, the present invention provides an ultra-low nitrogen combustion system and method.

[0004] The object of the present invention is to provide an ultra-low nitrogen combustion system and method to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an ultra-low nitrogen combustion system and method;

[0006] A working method of an ultra-low nitrogen combustion system, the working method comprising the following steps: supplying combustion-supporting air, injecting fuel gas, air-fuel mixing, premixed combustion and diffusion combustion:

[0007] Step A. Supplying combustion-supporting air: The fan supplies combustion-supporting air to each air supply channel, and most of the combustion-supporting air enters the main air duct;

[0008] Step B. injecting gas: injecting gas into the main air duct through multiple nozzles of the main gas system;

[0009] Step C. Air and fuel mixing: The combustion-supporting air and fuel gas are mixed in the main air duct, and the excess air coefficient α is greater than 1.2;

[0010] Step D. Premixed combustion: Premixed combustion is completed in the combustion chamber. Due to the relative excess of air, it is lean premixed combustion with low combustion temperature and short combustion range, which is conducive to suppressing NOx generation;

[0011] Step E. Diffusion combustion: A small portion of the combustion-supporting air enters the auxiliary air duct, and after swirling through the swirl disk, it completes diffusion combustion in the combustion chamber with the gas sprayed from the nozzle of the auxiliary gas system, and the gas excess air coefficient α is less than 1.

[0012] An ultra-low nitrogen combustion system, comprising:

[0013] The burner comprises a fan, an air supply channel, a main gas system and an auxiliary gas system, and the air supply channel comprises an inner air duct and an outer air duct, and the outer air duct is sleeved on the outer side of the inner air duct, and the air outlet end of the fan is screwed and fixed to the necking interface through a flange;

[0014] A main gas system, the main gas system comprising a gas collection bag, a plurality of branch pipes and a plurality of nozzles, and the gas collection bag and the nozzles are connected through the branch pipes;

[0015] The auxiliary gas system includes a gas pipe, a nozzle and a swirl disk, wherein the nozzle is arranged at the front end of the inner wind tube, and a swirl disk is arranged outside the nozzle, and a plurality of holes are evenly distributed around the nozzle.

[0016] Furthermore, the channel between the inner air duct and the outer air duct is a main air duct, and the channel in the inner air duct is an auxiliary air duct, and swirl blades and straight blades are respectively arranged on both sides of the main air duct.

[0017] Furthermore, the front end of the outer air cylinder is shorter than the front end of the inner air cylinder, and the cross-section of the front end of the outer air cylinder is a concentric circle structure with that of the inner air cylinder.

[0018] Furthermore, the nozzles are evenly distributed into four groups around the central axis of the burner, and the ends of the nozzles are screwed and fixed to the "L"-shaped branch pipes.

[0019] Furthermore, the swirl blades are arranged obliquely inside the main air duct, and a plurality of groups of swirl blades are evenly arranged at circumferential positions outside the inner air cylinder, and the swirl blades are arranged downstream of the nozzle.

[0020] Furthermore, the fan provides the combustion-supporting air required for combustion, and the combustion-supporting air enters the main air duct and mixes with the fuel gas ejected from the nozzle. At the same time, the mixed gas flows out from the main air duct and completes premixed combustion in the combustion chamber. A small portion of the combustion-supporting air enters the auxiliary air duct, and after swirling through the swirl disk, it completes diffuse combustion in the combustion chamber with the fuel gas ejected from the nozzle of the auxiliary fuel gas system.

[0021] Compared with the prior art, the beneficial effects of the present invention are: utilizing the oxygen in the hot flue gas after the peripheral lean-burn premixed combustion to complete the subsequent combustion; since the fuel gas is relatively excessive, it is rich fuel gas combustion, and the combustion temperature is low, which is beneficial to suppressing the formation of NOx; and since the hot flue gas participates in its combustion, the formation of NOx can be further reduced; reducing the factory's NOx processing volume and protecting the environment at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a cross-sectional view of the present invention;

[0023] Figure 2 This is a schematic diagram of the combustion head of this embodiment;

[0024] Figure 3 For the present invention Figure 1 Schematic diagram of the local structure in;

[0025] Figure 4 For the present invention Figure 1 Schematic diagram of gas flow field in ;

[0026] Figure 5 For the present invention Figure 4 A magnified schematic diagram of the local structure.

[0027] In the figure: 100, burner; 101, fan; 102, necking interface; 110, air supply channel; 111, swirl plate; 112, outer air duct; 113, inner air duct; 114, blade; 120, main gas system; 121, gas collecting bag; 122, branch pipe; 123, nozzle; 130, auxiliary gas system; 131, gas pipe; 132, nozzle; 133, swirl disk; 200, combustion chamber. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Specific implementation method 1: Please refer to Figure 1-5 , the present invention provides a technical solution: an ultra-low nitrogen combustion system and method;

[0030] A working method of an ultra-low nitrogen combustion system, the working method comprising the following steps: supplying combustion-supporting air, injecting fuel gas, air-fuel mixing, premixed combustion and diffusion combustion:

[0031] Step A. Supplying combustion-supporting air: The fan 101 supplies combustion-supporting air to each air supply channel 110, and most of the combustion-supporting air enters the main air duct;

[0032] Step B. Injecting gas: injecting gas into the main air duct through the multiple nozzles 123 of the main gas system 120;

[0033] Step C. Air and fuel mixing: The combustion-supporting air and fuel gas are mixed in the main air duct, and the excess air coefficient α is greater than 1.2;

[0034] Step D. Premixed combustion: Premixed combustion is completed in the combustion chamber 200. Due to the relative excess of air, it is lean premixed combustion with low combustion temperature and short combustion range, which is conducive to suppressing NOx generation;

[0035] Step E. Diffusion combustion: A small portion of the combustion-supporting air enters the auxiliary air duct, and after swirling through the swirl disk 133, it completes diffusion combustion with the gas sprayed from the nozzle 132 of the auxiliary gas system 130 in the combustion chamber 200, and the gas excess air coefficient α is less than 1.

[0036] An ultra-low nitrogen combustion system includes: a burner 100, a main gas system 120 and an auxiliary gas system 130;

[0037] The burner 100 includes a fan 101, an air supply channel 110, a main gas system 120 and an auxiliary gas system 130, and the air supply channel 110 includes an inner air cylinder 113 and an outer air cylinder 112, and the outer air cylinder 112 is sleeved on the outer side of the inner air cylinder 113, and the air outlet end of the fan 101 is screwed and fixed to the neck interface 102 through a flange;

[0038] The main gas system 120 includes a gas collection bag 121, a plurality of branch pipes 122 and a plurality of nozzles 123, and the gas collection bag 121 and the nozzles 123 are connected through the branch pipes 122;

[0039] The auxiliary gas system 130 includes a gas pipe 131, a nozzle 132 and a swirl disk 133. The nozzle 132 is arranged at the front end of the inner wind tube 113. The swirl disk 133 is arranged outside the nozzle 132, and the nozzle 132 has multiple holes evenly distributed around the circumference.

[0040] The working principle of the device is as follows: the fan 101 supplies combustion-supporting air to each air supply channel 110, most of the combustion-supporting air enters the main air duct, and the combustion gas is sprayed into the main air duct through multiple nozzles 123 of the main gas system 120, and the combustion-supporting air and the combustion gas are mixed in the main air duct; its excess air coefficient α is greater than 1.2, and the premixed combustion is completed in the combustion chamber 200. Due to the relative excess of air, it is lean premixed combustion, the combustion temperature is low, the combustion process is short, and it is conducive to suppressing the generation of NOx;

[0041] A small portion of the combustion-supporting air enters the auxiliary air duct, and after swirling through the swirl disk, it completes diffusion combustion with the gas sprayed from the nozzle 132 of the auxiliary gas system 130 in the combustion chamber 200, and the gas excess air coefficient α is less than 1; in the central rich-burning zone, the unfinished fuel is burned, and the subsequent combustion is completed by using the oxygen in the hot flue gas after the peripheral lean-burning premixed combustion. Since the gas is relatively excessive, it is rich-gas combustion with a low combustion temperature, which is beneficial to suppressing the formation of NOx, and since the hot flue gas participates in its combustion, the formation of NOx can be further reduced, thereby reducing the factory's NOx processing capacity and protecting the environment at the same time.

[0042] Specific implementation method three: This implementation method is a further limitation of specific implementation method two. The channel between the inner air duct 113 and the outer air duct 112 is the main air duct, and the channel inside the inner air duct 113 is the auxiliary air duct. At the same time, swirl plates 111 and straight blades 114 are respectively provided on both sides of the main air duct.

[0043] like Figure 1 As shown: a swirl blade 111 is set on one side of the nozzle 123 in the main air duct to enhance the mixing of the combustion-supporting air and the fuel gas in the main air duct; a straight blade 114 is set on the other side of the main air duct to convert the mixed gas in the main air duct from a rotating flow to a direct flow before it flows out of the main air duct, thereby facilitating the formation of a flue gas circulation inside the combustion chamber 200.

[0044] Specific implementation method 4: This implementation method is a further limitation of specific implementation method 2. The front end of the outer air cylinder 112 is shorter than the front end of the inner air cylinder 113 , and the front end of the outer air cylinder 112 is a concentric circle structure with the cross section of the inner air cylinder 113 .

[0045] like Figure 1 As shown: the front end of the outer wind tube 112 is shorter than the inner wind tube 113, which is beneficial to separate the central diffusion combustion flame from the peripheral premixed combustion flame.

[0046] Specific implementation method five: This implementation method is a further limitation of specific implementation method two. The nozzles 123 are evenly distributed in four groups around the central axis of the burner 100 , and the ends of the nozzles 123 are screwed and fixed to the “L”-shaped branch pipe 122 .

[0047] like Figure 1 As shown: the fan 101 supplies combustion-supporting air to each air supply channel 110 , most of the combustion-supporting air enters the main air duct, and sprays gas into the main air duct through multiple nozzles 123 of the main gas system 120 .

[0048] Specific implementation method six: This implementation method is a further limitation of specific implementation method three. The swirl blades 111 are arranged obliquely inside the main air duct, and multiple groups of swirl blades 111 are evenly arranged at the outer circumferential position of the inner air cylinder 113. At the same time, the swirl blades 111 are arranged downstream of the nozzle 123.

[0049] like Figure 4-5 As shown: Figure 4-5 Schematic diagram of the flow direction of various gases in the invention:

[0050] Meaning: combustion air; Meaning: fuel;

[0051] Indicates: mixed gas; Meaning: smoke;

[0052] Specific embodiment seven: This embodiment is a further limitation of specific embodiment two, the fan 101 provides the combustion-supporting air required for combustion, and the combustion-supporting air enters the main air duct and mixes with the fuel gas ejected from the nozzle 123, and at the same time, the mixed gas flows out from the main air duct and completes premixed combustion in the combustion chamber 200, and a small portion of the combustion-supporting air enters the auxiliary air duct, and after swirl through the swirl disk 133, it completes diffusion combustion with the fuel gas ejected from the nozzle 132 of the auxiliary fuel gas system 130 in the combustion chamber 200.

[0053] like Figure 1 As shown: the fan 101 is connected to the outer wind tube 112 through the neck interface 102 to provide the combustion-supporting air required for combustion. Most of the combustion-supporting air enters the main air duct and mixes with the fuel gas ejected from the nozzle 123. The mixed gas flows out of the main air duct and completes premixed combustion in the combustion chamber 200; the center of this system is rich combustion, and the outer circle is frequent premixed combustion, which can reduce the combustion temperature and inhibit the formation of NOx without changing the overall chemical equivalence ratio; combustion is completed in the main combustion chamber, the flame is short and uniform, and the heat exchange efficiency can be greatly improved.

[0054] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A working method of an ultra-low nitrogen combustion system, the ultra-low nitrogen combustion system comprising: A burner (100), the burner (100) comprising a fan (101), an air supply channel (110), a main gas system (120) and an auxiliary gas system (130), wherein the air supply channel (110) comprises an inner air cylinder (113) and an outer air cylinder (112), wherein the outer air cylinder (112) is sleeved on the outside of the inner air cylinder (113), and an air outlet end of the fan (101) is screwed and fixed to the necking interface (102) via a flange; A main gas system (120), the main gas system (120) comprising a gas collection bag (121), a plurality of branch pipes (122), and a plurality of nozzles (123), wherein the gas collection bag (121) and the nozzles (123) are connected via the branch pipes (122); An auxiliary gas system (130), the auxiliary gas system (130) comprising a gas pipe (131), a nozzle (132) and a swirl disk (133), wherein the nozzle (132) is arranged at the front end of the inner wind tube (113), and the swirl disk (133) is arranged outside the nozzle (132), and the nozzle (132) has a plurality of holes evenly distributed in the circumferential direction; The passage between the inner air duct (113) and the outer air duct (112) is a main air duct, and the passage inside the inner air duct (113) is an auxiliary air duct, and swirl blades (111) and straight blades (114) are respectively arranged on both sides of the main air duct; The front end of the outer air cylinder (112) is shorter than the front end of the inner air cylinder (113), and the cross-section of the front end of the outer air cylinder (112) and the inner air cylinder (113) is a concentric circle structure; The working method includes the following steps: supplying combustion-supporting air, injecting fuel gas, air-fuel mixing, premixed combustion and diffusion combustion, and is characterized in that: Step A. supplying combustion-supporting air: the fan (101) supplies combustion-supporting air into each air supply channel (110), and most of the combustion-supporting air enters the main air duct; Step B. injecting gas: injecting gas into the main air duct through a plurality of nozzles (123) of the main gas system (120); Step C. Air and fuel mixing: The combustion-supporting air and fuel gas are mixed in the main air duct, and the excess air coefficient α is greater than 1.2; Step D. Premixed combustion: Premixed combustion is completed in the combustion chamber (200). Since the air is relatively excessive, it is lean premixed combustion, with low combustion temperature and short combustion range, which is conducive to suppressing NOx generation; Step E: Diffusion combustion: A small portion of the combustion-supporting air enters the auxiliary air duct, and after being swirled by the swirl disk (133), it completes diffusion combustion in the combustion chamber (200) with the gas sprayed from the nozzle (132) of the auxiliary gas system (130), and the gas excess air coefficient α is less than 1.

2. The working method of an ultra-low nitrogen combustion system according to claim 1, characterized in that: The nozzles (123) are evenly distributed in four groups around the central axis of the burner (100), and the ends of the nozzles (123) are screwed and fixed to the "L"-shaped branch pipe (122).

3. The working method of an ultra-low nitrogen combustion system according to claim 1, characterized in that: The swirl blades (111) are arranged at an angle inside the main air duct, and multiple groups of swirl blades (111) are evenly arranged at circumferential positions outside the inner air cylinder (113), and the swirl blades (111) are arranged downstream of the nozzle (123).

4. The working method of an ultra-low nitrogen combustion system according to claim 1, characterized in that: The fan (101) provides combustion-supporting air required for combustion, and the combustion-supporting air enters the main air duct and mixes with the fuel gas ejected from the nozzle (123). At the same time, the mixed gas flows out from the main air duct and completes premixed combustion in the combustion chamber (200). A small portion of the combustion-supporting air enters the auxiliary air duct, and after swirling through the swirl disk (133), it completes diffusion combustion in the combustion chamber (200) with the fuel gas ejected from the nozzle (132) of the auxiliary fuel gas system (130).

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