Low-nitrogen emission combustion furnace

Abstract

The utility model discloses a low-nitrogen emission combustion furnace, which belongs to the field of boiler combustion and comprises a furnace body, and a main combustion area, a re-combustion area and a burnout area are arranged in the furnace body from bottom to top. Annular pieces are arranged in the main combustion area, the re-combustion area and the burnout area and comprise a lower-layer annular piece, a middle-layer annular piece and an upper-layer annular piece, and the main combustion area, the re-combustion area and the burnout area are connected with the lower-layer annular piece, the middle-layer annular piece and the upper-layer annular piece correspondingly; the rotating spiral slices in the gas inlet pipe enable air and fuel gas to be fully premixed, strong rotating airflow is formed in a main combustion area, a fuel-rich and low-oxygen environment is created, generation of nitric oxide is inhibited, sufficient combustion of the fuel is promoted, a horizontal nozzle of the middle-layer annular piece diffuses extra premixed fuel, nitric oxide is reduced through reducing substances such as hydrocarbons, unburnt substances are consumed, and the combustion efficiency of the fuel is improved. And the upper-layer annular part is provided with inclined downward nozzles with small inclination force, so that supplemented air and residual combustible components are softly mixed and burnt out in a burnout area, and the emission of nitrogen oxides is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of boiler combustion, and in particular relates to a low-nitrogen emission combustion furnace. Background Art

[0002] In industrial production and daily life, combustion furnaces are widely used in various heating, drying, smelting and other processes. Traditional combustion furnaces mainly achieve energy conversion by directly mixing fuel with air and igniting it, but this method has many disadvantages.

[0003] On the one hand, in the combustion process of traditional combustion furnaces, the uneven mixing of fuel and air leads to incomplete combustion, which is a common phenomenon. This not only causes energy waste, reduces energy utilization, and increases production costs, but also produces a large amount of unburned substances, such as carbon monoxide and hydrocarbons. These substances will cause serious environmental pollution when discharged into the atmosphere. On the other hand, when traditional combustion furnaces burn at high temperatures, they will cause nitrogen and oxygen in the air to react and produce a large amount of nitrogen oxides. Nitrogen oxides are an important factor in the formation of environmental problems such as acid rain and photochemical smog, and are extremely harmful to the ecological environment and human health. Utility Model Content

[0004] The purpose of the utility model is to provide a low nitrogen emission combustion furnace to solve the problem of insufficient combustion and the generation of a large amount of nitrogen oxides. problem.

[0005] To achieve the above object, the utility model provides the following technical solutions: a low nitrogen emission combustion furnace, comprising a furnace body, wherein the furnace body is provided with a main combustion zone, a reburning zone and a burnout zone from bottom to top;

[0006] Rings are arranged in the main combustion zone, the reburning zone and the burnout zone, and the rings include a lower ring, a middle ring and an upper ring. The main combustion zone, the reburning zone and the burnout zone are connected to the lower ring, the middle ring and the upper ring respectively. A plurality of nozzles are arranged on the upper ring, the middle ring and the lower ring, and the middle ring and the lower ring are injected with premixed gas.

[0007] A plurality of spiral slices are arranged inside the air intake pipe connected to the annular member.

[0008] Furthermore, the multiple nozzles on the upper ring member are all arranged rotationally symmetrically and obliquely downward, and the extension lines of the multiple nozzles on the upper ring member intersect directly below the center of the upper ring member.

[0009] Furthermore, the multiple nozzles on the middle ring member are arranged horizontally and rotationally symmetrically.

[0010] Furthermore, the multiple nozzles on the lower ring member are all arranged rotationally symmetrically and obliquely upward, and the extension lines of the multiple nozzles on the lower ring member intersect directly above the center of the lower ring member.

[0011] Furthermore, the inclination of the nozzle on the lower ring member is greater than the inclination of the nozzle on the upper ring member.

[0012] Furthermore, the plurality of spiral slices are alternately rotated 90°.

[0013] Furthermore, a variety of sensors are arranged in the furnace body, and the various sensors include oxygen sensors, temperature sensors, calorific value sensors and gas sensors.

[0014] Furthermore, the various sensors are all connected to a control system.

[0015] Furthermore, the nozzle is arranged at the annular opening of the annular member.

[0016] Compared with the prior art, the beneficial effects of the utility model are:

[0017] (1) In this low-nitrogen emission burner, the rotating spiral slices in the air intake pipe allow the air and gas to be fully premixed, forming a strong rotating airflow in the main combustion zone, creating a fuel-rich, low-oxygen environment to inhibit the generation of nitrogen oxides and promote the full combustion of the fuel. The horizontal nozzles of the middle ring diffuse additional premixed fuel, reduce nitrogen oxides through reducing substances such as hydrocarbons, and consume unburned materials. The upper ring has a small downward nozzle with a small inclination force, so that the supplementary air and the remaining combustible components are gently mixed and burned in the burnout zone, thereby reducing the emission of nitrogen oxides.

[0018] (2) In this low-nitrogen emission combustion furnace, the nozzles on the lower ring member that rotate upward obliquely make the fuel gas and oxygen spray upward from the bottom in the main combustion zone, forming a strong rotating airflow that quickly fills the entire main combustion zone space, greatly increasing the contact area and mixing probability between the two; the horizontal rotationally symmetrical nozzles on the middle ring member diffuse the additional fuel gas horizontally to the reburning zone, where it is in full contact and mixed with the gas with different oxygen contents rising from the main combustion zone and the air introduced by the middle nozzle, further expanding the mixing range; the nozzles on the upper ring member that rotate downward obliquely and symmetrically with a smaller inclination force make the fuel gas and supplementary air blend softly from top to bottom in the burnout zone, ensuring that oxygen and fuel gas can be fully and efficiently mixed in different combustion stages. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of a low nitrogen emission burner;

[0020] Figure 2 for Figure 1 Schematic diagram of cross section of middle reburning zone;

[0021] Figure 3 It is a schematic diagram of a three-layer ring member;

[0022] Figure 4 A cross-sectional view of the intake pipe.

[0023] In the figure: 10, furnace body; 210, lower ring member; 220, middle ring member; 230, upper ring member; 240, nozzle; 250, air inlet pipe; 251, spiral slice; 20A, upper nozzle extension line is located at the middle ring member; 20B, lower nozzle extension line is located inside the middle ring member. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the embodiments.

[0025] The following examples are used to illustrate the present invention, but cannot be used to limit the scope of protection of the present invention. The conditions in the examples can be further adjusted according to specific conditions, and simple improvements to the method of the present invention under the premise of the concept of the present invention are all within the scope of protection claimed by the present invention.

[0026] See also Figure 1-4 The utility model provides a low nitrogen emission combustion furnace, comprising a furnace body 10, wherein the furnace body 10 is provided with a main combustion zone, a reburning zone and a burnout zone from bottom to top;

[0027] The excess air coefficient of the main combustion zone is α=0.85-0.95, and the gas supplementary combustion nozzle is arranged;

[0028] The reburning zone is located at 25%-35% of the furnace height and is equipped with a gas injection device with an injection speed of ≥60m / s. and Molar ratio 1.2-1.5;

[0029] In the burnout zone, three-stage secondary air nozzles are configured, and the oxygen concentration gradient is controlled to be 19%→22%→24%;

[0030] Annular members are arranged in the main combustion zone, the reburning zone and the burnout zone, and the annular members include a lower annular member 210 , a middle annular member 220 and an upper annular member 230 .

[0031] The main combustion zone, the reburning zone and the burnout zone are respectively connected to the lower ring member 210, the middle ring member 220 and the upper ring member 230. Sixteen nozzles 240 are arranged on the upper ring member 230, the middle ring member 220 and the lower ring member 210. The sixteen nozzles on the upper ring member 230 are all arranged obliquely downward and rotationally symmetrically, and the extension lines of the sixteen nozzles on the upper ring member 230 intersect directly below the center of the upper ring member 230; the sixteen nozzles on the middle ring member 220 are arranged horizontally and rotationally symmetrically; the sixteen nozzles on the lower ring member 210 are all arranged obliquely upward and rotationally symmetrically, and the extension lines of the sixteen nozzles on the lower ring member 210 intersect directly above the center of the lower ring member 210.

[0032] The outer walls of the lower ring member 210 , the middle ring member 220 and the upper ring member 230 are all connected to the inner wall of the furnace body 10 , and the nozzles are arranged at the annular openings of the ring members.

[0033] In the main combustion zone, the nozzles on the lower ring member 210 are symmetrically arranged in an oblique upward rotation, so that the fuel and air are sprayed upward from the bottom to quickly fill the main combustion zone space, promote full mixing of the fuel and air, make the combustion more intense, and improve the combustion efficiency.

[0034] The horizontal rotationally symmetrical nozzles of the middle ring 220 can diffuse the extra fuel horizontally, expand the combustion range, further consume the unburned materials, and reduce the loss of incomplete combustion. The nozzles of the upper ring in the burnout zone are arranged rotationally symmetrically downward, so that the fuel and air can be rotated and covered from top to bottom, ensuring that the remaining combustible components are completely burned and improving energy utilization.

[0035] The tilting force of the sixteen nozzles on the lower ring 210 is greater than the tilting force of the sixteen nozzles on the upper ring 230, so that the circle 20B formed by the extension line of the upper nozzle in the middle ring is larger than the circle 20A formed by the extension line of the lower nozzle in the middle ring; the lower ring 210 is located in the main combustion zone, and its action range is wider and more dispersed than the airflow ejected from the nozzle of the upper ring 230. This dispersion is conducive to fully mixing the fuel and air in the main combustion zone, increasing the combustion area, and at the same time playing a stronger supporting role for the flame root, so as to better stabilize the flame, improve the combustion efficiency, and make the fuel burn as fully as possible in the main combustion zone; the upper ring 230 is in the burnout zone, and the smaller tilting force makes the fuel and air spray more concentratedly and softly, mainly to further burn out the remaining combustible components.

[0036] The air inlet pipe 250 connected to the lower ring 210, the middle ring 220 and the upper ring 230 is provided with a plurality of spiral slices 251, which are arranged to rotate 90 degrees alternately; when the air inlet pipe 250 injects air and gas at the same time, the air and gas will constantly change the flow direction and speed in the pipe through the alternating rotation structure of the plurality of spiral slices 251, forming a complex turbulent state, greatly increasing the contact area and mixing degree of the air and gas, so that the two can be fully premixed before entering the nozzle of the ring. When the premixed gas is ejected from the nozzles on each ring, more efficient and stable combustion can be achieved in the main combustion zone, reburning zone and burnout zone of the combustion furnace, further improving the combustion efficiency.

[0037] A plurality of sensors may be provided in the furnace body 10, and the plurality of sensors are used to collect data such as oxygen concentration inside the furnace body 10, furnace temperature field distribution, fuel calorific value, nitrogen oxides, nitric oxide, etc., and the combustion of the combustion furnace is systematically controlled through systematic data result analysis to realize automated system control.

[0038] The working principle and use process of the utility model are as follows: when the low-nitrogen emission combustion furnace is working, air and fuel gas simultaneously flow into the intake pipe connecting the lower ring member 210, the middle ring member 220 and the upper ring member 230. Special structures such as the spiral slices 251 arranged in an alternating 90-degree rotation in the intake pipe promote the formation of complex turbulence between the two, thereby achieving full premixing; the lower ring member 210 is located in the main combustion zone, and its sixteen nozzles with strong upward rotational symmetry and strong inclination force strongly eject the premixed gas, forming a strong rotating airflow upward at the bottom of the main combustion zone. The main combustion zone is relatively fuel-rich and the oxygen supply is insufficient, which inhibits the generation of thermal nitrogen oxides. After part of the fuel is fully burned, unburned substances are generated. The generation of thermal nitrogen oxides is closely related to high temperature and oxygen concentration. In this environment, the oxygen content in the high-temperature area is low, which inhibits the process of nitrogen in the air reacting with oxygen at high temperature to generate nitrogen oxides;

[0039] The gas with unburned matter rises to the reburning zone, and the sixteen horizontally rotationally symmetrically arranged nozzles on the middle ring member 220 diffuse the additional premixed fuel horizontally, and the reducing substances such as hydrocarbons in the fuel react with the nitrogen oxides produced by the previous combustion, while continuing to burn the unburned matter;

[0040] The remaining unburned materials enter the burnout zone, and the sixteen downwardly slanted, rotationally symmetrical and lightly tilted nozzles on the upper ring member 230 allow the supplementary air to be gently and fully mixed with the remaining combustible components from top to bottom, completely burning them and avoiding the generation of a large amount of nitrogen oxides at high temperatures, ultimately achieving low nitrogen emissions and efficient combustion.

[0041] 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 low nitrogen emission combustion furnace, comprising a furnace body (10), characterized in that: The furnace body (10) is provided with a main combustion zone, a reburning zone and a burnout zone from bottom to top; Annular parts are arranged in the main combustion zone, the reburning zone and the burnout zone, and the annular parts include a lower annular part (210), a middle annular part (220) and an upper annular part (230); the main combustion zone, the reburning zone and the burnout zone are respectively connected to the lower annular part (210), the middle annular part (220) and the upper annular part (230); and the upper annular part (230), the middle annular part (220) and the lower annular part (210) are all provided with a plurality of nozzles; A plurality of spiral slices (251) are arranged inside the air intake pipe (250) connected to the annular member.

2. A low nitrogen emission combustion furnace according to claim 1, characterized in that: The multiple nozzles on the upper annular member (230) are all arranged rotationally symmetrically and obliquely downward, and the extension lines of the multiple nozzles on the upper annular member (230) intersect directly below the center of the upper annular member (230).

3. A low nitrogen emission combustion furnace according to claim 1, characterized in that: The multiple nozzles on the middle-layer annular member (220) are arranged horizontally and rotationally symmetrically.

4. A low nitrogen emission combustion furnace according to claim 1, characterized in that: The multiple nozzles on the lower ring member (210) are all arranged rotationally symmetrically and obliquely upward, and the extension lines of the multiple nozzles on the lower ring member (210) intersect directly above the center of the lower ring member (210).

5. A low nitrogen emission combustion furnace according to claim 1, characterized in that: The inclination of the nozzle on the lower annular member (210) is greater than the inclination of the nozzle on the upper annular member (230).

6. A low nitrogen emission combustion furnace according to claim 1, characterized in that: The plurality of spiral slices (251) are arranged to be rotated 90° alternately.

7. A low nitrogen emission combustion furnace according to claim 1, characterized in that: A plurality of sensors are arranged in the furnace body (10), and the plurality of sensors include an oxygen sensor, a temperature sensor, a calorific value sensor and a gas sensor.

8. A low nitrogen emission combustion furnace according to claim 1, characterized in that: The nozzle is arranged at the annular opening of the annular member.

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