Low-heating-value gas burner and waste gas recovery process

Abstract

The invention discloses a low-heating-value gas burner and a waste gas recovery process. The combustor comprises a wet gas box, a combustion-supporting gas box, a dry gas box and a flame tube which are sequentially connected. An inner barrel is installed in the flame barrel, two stages of spinning disks, a plurality of dry gas spraying pipes and a plurality of wet gas spraying pipes are further installed in the combustor, and a plurality of gas spraying holes are formed in the end area of each spraying pipe. According to the disclosed process, wet gas and dry gas are subjected to combustion treatment by adopting a boiler provided with the combustor disclosed by the invention. According to the burner, waste gas can be fully burnt out, and emission of combustible materials such as CO in flue gas is reduced; a first-stage wet gas spray pipe, a second-stage wet gas spray pipe and a dry gas spray pipe in the combustor are sequentially arranged in a flame tube in the axial direction in a staggered mode by a certain distance, and the low-nitrogen combustion effect is achieved while the flame temperature is reduced. According to the invention, clean and efficient utilization of resources is realized, and energy waste is avoided; and meanwhile, the problems that peculiar smell is generated during combustion emission of an original torch, the COD content of condensate is high, and treatment is difficult are solved.

Description

Technical Field

[0001] The present invention relates to industrial waste gas treatment technology, and particularly to a low calorific value gas burner and a waste gas recovery process. Background Art

[0002] In the production devices of coal chemical enterprises, waste gas is discharged, and the calorific value is relatively low (generally 5600 - 11000 KJ / m 3 ), and the combustible components mainly include hydrogen, carbon monoxide, etc. Among them, the expansion gas from the methanol synthesis device, the non-permeate gas from the methanol synthesis device, and the non-condensable gas from the shift device are wet gases; the non-condensable gas from the methanol rectification device is a dry gas.

[0003] In the prior art, the discharged waste gas is collected and transported through a pipeline to a separation tank to separate liquid and solid impurities in the gas. Then the gas enters a water seal tank to further separate the condensate or particulate matter in the waste gas and then passes through a pipeline and enters a flare system for combustion treatment and then discharge.

[0004] In the above treatment method, discharging the waste gas (including dry gas and wet gas) to the flare for combustion causes huge energy waste. At the same time, if the discharged waste gas contains ammonia, hydrogen sulfide, etc., and is discharged through the flare combustion, it will cause peculiar smell and environmental pollution. In addition, the discharged waste gas contains organic substances such as alcohols, resulting in a very high COD content in the condensate of the flare system, and it is difficult to recover and treat the flare condensate. Summary of the Invention

[0005] Aiming at the defects or deficiencies of the prior art, the present invention first provides a low calorific value gas burner.

[0006] To this end, the burner provided by the present invention includes a wet gas tank, an auxiliary combustion gas tank, a dry gas tank, and a flame tube; a wet gas inlet is provided on the wet gas tank, an auxiliary combustion gas inlet is provided on the auxiliary combustion gas tank, and a dry gas inlet is provided on the dry gas tank;

[0007] The wet gas tank, the auxiliary combustion gas tank, the dry gas tank, and the flame tube are arranged in sequence along the axis, and the flame tube passes through the dry gas tube and communicates with the auxiliary combustion gas tank. At the same time, a dry gas cavity is formed between the flame tube and the dry gas tank;

[0008] An inner tube is installed in the flame tube, and the inner tube is coaxial with the flame tube; a plurality of first-stage swirl vanes are installed in the inner tube, and a plurality of second-stage swirl vanes are installed between the inner tube and the flame tube;

[0009] A plurality of through holes are provided on the part of the flame tube located in the dry gas cavity; each through hole is communicated with a dry gas spray pipe, and the dry gas spray pipe extends axially into the flame tube and is located on the outer periphery of the inner tube. One end of the dry gas spray pipe communicates with the dry gas cavity through the corresponding through hole, and a plurality of spray holes A are opened in the other axial end region;

[0010] A plurality of first-stage wet gas nozzles and a plurality of second-stage wet gas nozzles are communicated with the axial end wall of the wet gas chamber. Among them, the plurality of first-stage wet gas nozzles are distributed in the central area of the axial end wall of the wet gas chamber and extend axially into the combustion chamber and pass through the inner cylinder; the plurality of second-stage wet gas nozzles are distributed around the plurality of first-stage wet gas nozzles and extend axially into the combustion chamber and are located on the outer periphery of the inner cylinder; a plurality of spray holes B are provided in the axial end area of each first-stage wet gas nozzle passing through the inner cylinder, and a plurality of spray holes C are provided in the axial end area of each second-stage wet gas nozzle far from the wet gas chamber.

[0011] Axially, the inner cylinder, the pipe wall area where the plurality of spray holes B are distributed, the pipe wall area where the plurality of spray holes C are distributed, and the pipe wall area where the plurality of spray holes A are distributed are arranged in sequence.

[0012] An optional solution is that, circumferentially, the dry gas nozzles and the second-stage wet gas nozzles are circumferentially spaced apart.

[0013] An optional solution is that, circumferentially, the dry gas nozzles and the second-stage wet gas nozzles are circumferentially spaced apart, and a single dry gas nozzle is provided between the plurality of second-stage wet gas nozzles.

[0014] An optional solution is that a plurality of spray holes A are evenly distributed on the end side wall of the dry gas nozzle and a spray hole A is provided on the end wall; a plurality of spray holes B are evenly distributed on the end side wall of the first-stage wet gas nozzle and a spray hole B is provided on the end wall, and a plurality of spray holes C are evenly distributed on the end side wall of the second-stage wet gas nozzle and a spray hole C is provided on the end wall. A further optional solution is that a spray hole A is provided on the end wall of the dry gas nozzle; a spray hole B is provided on the end wall of the first-stage wet gas nozzle, and a spray hole C is provided on the end wall of the second-stage wet gas nozzle.

[0015] In a further solution, the burner of the present invention further includes an igniter installation pipe, which axially passes through the wet gas chamber, the combustion-supporting gas chamber, the dry gas chamber and the combustion chamber in sequence and extends into the inner cylinder; the plurality of first-stage swirl vanes are installed on the igniter installation pipe.

[0016] In some further solutions, the burner of the present invention further includes a flame detector installation pipe, which axially passes through the wet gas chamber, the combustion-supporting gas chamber, the dry gas chamber and the combustion chamber in sequence and extends into the inner cylinder beside the igniter installation pipe, and at the same time, an angle of 3° to 5° is formed between the axis of the flame detector installation pipe and the axis of the igniter installation pipe.

[0017] The present invention further provides an exhaust gas recovery process, in which a boiler is used to burn wet gas and dry gas. The above-mentioned burner is installed in the boiler, and the burner is arranged between the secondary air outlet and the lower SOFA air outlet of the boiler. The wet gas enters the liquid separation tank for mixing, and after separating the liquid and solid impurities in the gas, it is sent to the low calorific value gas burner in the boiler for combustion. The dry gas is sent to the low calorific value gas burner in the boiler for combustion. Further, the liquid separated by the liquid separation tank is sent to the separation tank of the flare system.

[0018] The low calorific value gas burner of the present invention can ensure that the exhaust gas is fully burned out, reducing the emissions of combustibles such as CO in the flue gas. The primary and secondary wet gas nozzles and the dry gas nozzle in the burner are arranged axially staggered by a certain distance in the flame tube, which helps to achieve the effect of low nitrogen combustion while reducing the flame temperature.

[0019] In the preferred solution, the head of the exhaust gas nozzle for flare emission of the burner is closed, and a spray hole is provided at the central axial position of the nozzle mouth, and the remaining spray holes are evenly arranged circumferentially along the head of the nozzle. Multiple rows and multiple circumferential spray holes can be set according to the treatment volume of the exhaust gas for flare emission.

[0020] The present invention sends the low calorific value gas (i.e., wet gas and dry gas) in the exhaust gas for flare emission to the boiler for combustion treatment, realizing the clean and efficient utilization of resources and avoiding energy waste. At the same time, it solves the problems of peculiar smell generated by the original flare combustion emission, high COD content of condensate, and difficult treatment; and saves the coal resource consumption of the original boiler, improving the economic benefit of boiler operation. Description of the Drawings

[0021] Figure 1 It is the internal structure drawing of the burner of the present invention.

[0022] Figure 2 It is the structure drawing of some components of the burner of the present invention.

[0023] Figure 3 It is Figure 1 the right view.

[0024] Figure 4 It is the distribution schematic diagram of the spray holes in the end area of each nozzle in Example 1.

[0025] Figure 5 It is the fluent software simulation results of the burners in Comparative Example 1 and Example 1; (a) is the velocity distribution contour map in the burner of Comparative Example 1, (b) is the pressure distribution contour map in the burner of Comparative Example 1, (c) is the velocity distribution contour map in the burner of Example 1, and (d) is the pressure distribution contour map in the burner of Example 1.

[0026] Figure 6 It is the distribution schematic diagram of the small spray holes between the dry gas tank and the flame tube in the comparative example.

[0027] Figure 7 It is the process schematic diagram for using the burner of the present invention to process wet gas and dry gas.

[0028] In the figure: 1 - ignition burner; 2 - ignition air interface; 3 - ignition fuel interface; 4 - flame detector installation pipe; 5 - wet gas tank; 6 - wet gas inlet; 7 - combustion-supporting gas tank; 8 - partition B; 9 - dry gas inlet; 10 - flame tube; 11 - inner cylinder; 12 - secondary wet gas spray pipe; 13 - primary wet gas spray pipe; 14 - dry gas spray pipe; 15 - primary swirl vane; 16 - secondary swirl vane; 17 - installation flange; 18 - combustion-supporting air inlet; 19 - partition A; 20 - protective sleeve; 21 - dry gas tank; 22 - connecting flange; 23 - igniter installation pipe; 24 - small spray holes. Specific embodiments

[0029] Unless otherwise specified, scientific and technical terms in this article are understood according to the knowledge of those of ordinary skill in the relevant fields.

[0030] The axial, circumferential and other directional or azimuthal terms described in the present invention are consistent with the corresponding directions or azimuths in the accompanying drawings of the specification. It should be noted that the accompanying drawings of the specification are intended to explain the present invention, and the solutions obtained by those skilled in the art through rotation, reversal and other transformations are within the scope of the disclosure of the present invention.

[0031] The boiler described in the present invention refers to a pulverized coal boiler, which is a steam boiler that uses pulverized coal as fuel. It grinds coal into fine powder and mixes it with air for combustion, and the heat is transferred to water to generate steam, which is widely used in industries such as chemical engineering, electric power, and metallurgy. The pulverized coal boiler consists of a furnace, a conventional burner, a steam-water system, a tail flue, etc. The furnace is the combustion site, and the inside is covered with water-cooled walls to absorb heat; the conventional burner is responsible for spraying the pulverized coal and air into the furnace; the steam-water system includes a steam drum, downcomers, and risers to complete the water circulation and steam generation; the tail flue is equipped with a superheater, economizer, air preheater, etc.

[0032] Example 1:

[0033] Refer to Figures 1 - 3 As shown, the burner of this embodiment includes a wet gas tank 5, a combustion-supporting gas tank 7, a dry gas tank 21 and a flame tube 10. As shown in the figure, the wet gas tank 5 is provided with a wet gas inlet 6, the combustion-supporting gas tank 7 is provided with a combustion-supporting gas inlet 18, and the dry gas tank 21 is provided with a dry gas inlet 9;

[0034] Axially, the wet gas gas box 5, the combustion-supporting gas gas box 7, the dry gas gas box 21 and the flame tube 10 are assembled in sequence (connected by welding or other means), and the flame tube 10 passes through the dry gas cylinder and communicates with the combustion-supporting gas gas box 7. Meanwhile, a dry gas cavity is formed between the outer wall of the flame tube and the inner wall of the dry gas gas box; the wet gas gas box 5, the combustion-supporting gas gas box 7 and the dry gas gas box 8 are structurally independent of each other and not connected, and each communicates with the flame tube 10 through a corresponding pipeline. Figure 1 In the shown burner, the wet gas gas box and the combustion-supporting gas gas box are separated by a partition A19, and the combustion-supporting gas gas box and the dry gas gas box are separated by a partition B8.

[0035] Meanwhile, an inner cylinder 11 is installed inside the flame tube, and the inner cylinder is coaxial with the flame tube; a plurality of first-stage swirl vanes 15 are installed inside the inner cylinder, and a plurality of second-stage swirl vanes 16 are installed between the inner cylinder and the flame tube.

[0036] A plurality of through holes are circumferentially formed in the part of the flame tube 10 located in the dry gas cavity; each through hole is communicated with a dry gas nozzle 14, and each dry gas nozzle extends axially into the flame tube 10 and is located outside the inner cylinder. One end of the dry gas nozzle communicates with the dry gas cavity through the corresponding through hole, and a plurality of spray holes A are formed in the other axial end region.

[0037] A plurality of first-stage wet gas nozzles 13 and a plurality of second-stage wet gas nozzles 12 are communicated with the axial end wall of the wet gas gas box 5. Among them, the plurality of first-stage wet gas nozzles are distributed in the central region of the axial end wall of the wet gas gas box and extend axially into the flame tube and pass through the inner cylinder; the plurality of second-stage wet gas nozzles are distributed around the plurality of first-stage wet gas nozzles and extend axially into the flame tube and are located outside the inner cylinder; a plurality of spray holes B are formed in the axial end region where each first-stage wet gas nozzle passes through the inner cylinder, and a plurality of spray holes C are formed in the axial end region of each second-stage wet gas nozzle far from the wet gas gas box.

[0038] Axially, the inner cylinder, the tube wall region where a plurality of spray holes B are distributed, the tube wall region where a plurality of spray holes C are distributed, and the tube wall region where a plurality of spray holes A are distributed are arranged in sequence.

[0039] Furthermore, the burner further includes an igniter installation pipe 23. An ignition burner 1 is installed in the igniter installation pipe, and an ignition air interface 2 and an ignition fuel gas interface 3 are provided thereon. When the burner is in use, the ignition burner is installed in the igniter installation pipe and extends into the inner cylinder 11. The used ignition burner 1 adopts a premixed structure, and ignition air and ignition fuel gas enter and mix respectively from the inner pipe and the outer pipe of the ignition burner and then are ejected. The igniter is installed at the center position of the ignition burner through the igniter installation pipe, and a pneumatic plugging and unplugging mechanism is used to control the entry and exit of the ignition burner.

[0040] After the ignition burner operates stably, wet gas and dry gas are started to be introduced, and corresponding combustion-supporting air (secondary air) is introduced. By adjusting the air-fuel ratio, the waste gas discharged from the torch is completely burned in the boiler.

[0041] Among them, after the moisture enters the moisture gas box through the moisture inlet 6, it enters the first-stage moisture spray pipe 13 and the second-stage moisture spray pipe 12 that are communicated with the moisture gas box respectively, and then is sprayed into the combustion chamber 10 through the spray holes at the ends of the first-stage moisture spray pipe 13 and the second-stage moisture spray pipe 12;

[0042] After the dry gas enters the dry gas cavity through the dry gas inlet 9, it enters the dry gas spray pipe 14 that is communicated with the dry gas cavity, and then is sprayed into the combustion chamber 10 through the spray holes at the end of the dry gas spray pipe 14;

[0043] The combustion-supporting gas (such as air or oxygen-containing gas) enters the combustion chamber 10 through the combustion-supporting air inlet 18. After flowing to the inner cylinder 11, part of the air enters the inner cylinder 11 and generates a primary swirling gas under the action of the primary swirl vane 15, which is mainly used for the combustion of the waste gas sprayed by the first-stage moisture spray pipe 13. Another part of the air generates a secondary swirling gas after the action of the secondary swirl vane 16 in the combustion chamber, which is mainly used for the combustion of the waste gas sprayed by the second-stage moisture spray pipe 12 and the dry gas spray pipe 14.

[0044] After the ignition burner ignites successfully, first open the combustion-supporting air inlet 13, then open the moisture inlet 6 and the dry gas inlet 9, and adjust the air and torch waste gas flow rates to meet the flow design requirements.

[0045] In a specific solution, the flow rate of the combustion-supporting air can be distributed by reasonably optimizing the size of the inner cylinder 11 (in this embodiment, the air flow rate outside the inner cylinder is 4.6 times that inside). In addition, in order to make the air in the central area of the combustion chamber less than the air required for the fuel, a negative oxygen combustion area is formed to reduce the generation of nitrogen oxides, and the nitrogen oxides are decomposed by the reduction products such as CO generated by the negative oxygen combustion. In the outer area of the combustion chamber, the fuel (torch waste gas) is burned by mixing with the excess air with a normal ratio to form an oxygen-rich combustion area, so that the fuel (torch waste gas) is fully burned out, ensuring the combustion efficiency and reducing the emission of combustibles such as CO in the flue gas. In the burner of the present invention, on the one hand, the inner cylinder and the primary and secondary swirl vanes are designed to realize the distribution of air to form a negative oxygen combustion area in the central area of the combustion chamber 10 and an oxygen-rich combustion area in the outer area.

[0046] In some other solutions, the distribution mode of the spray holes at the ends of the dry gas spray pipe and the moisture spray pipe can be optimized. In a preferred solution, a plurality of spray holes A are evenly distributed on the side wall of the end of the dry gas spray pipe, and a spray hole A is provided on the end wall; a plurality of spray holes B are evenly distributed on the side wall of the end of the first-stage moisture spray pipe, and a spray hole B is provided on the end wall; a plurality of spray holes C are evenly distributed on the side wall of the end of the second-stage moisture spray pipe, and a spray hole C is provided on the end wall. In addition, in a further preferred solution, the distribution of the spray holes in this embodiment is as Figure 4 shown. The ends of each spray pipe are closed, and a spray hole is provided at the central axial position of the end, and the remaining spray holes are evenly arranged along the side wall of the corresponding spray pipe end.

[0047] In a specific solution, the number of nozzles with reasonable data is set according to the wet gas and dry gas flow rates, and they are distributed as evenly as possible in the circumferential direction of the combustion chamber 10. As Figure 2 shown in the burner, the primary wet gas nozzle 13, the secondary wet gas nozzle 12, and the dry gas nozzle 14 are axially staggered and arranged in sequence within the combustion chamber 10, that is, along the direction from the gas inlet to the outlet. Among them, the end of the dry gas nozzle 14 where the spray holes are located is the farthest from the gas inlet end, followed by the end of the secondary wet gas nozzle 12 where the spray holes are located, and the end of the primary wet gas nozzle 13 where the spray holes are located is relatively close to the gas inlet end, realizing the partitioned injection of fuel gas, avoiding local high temperatures caused by concentrated combustion, effectively reducing the flame temperature, and contributing to achieving a low-nitrogen combustion effect.

[0048] In some other solutions, the burner further includes a flame detector installation pipe 4, which is installed beside the ignition burner. The central axis of the flame detector channel forms an angle of 3° to 5° with the central axis of the ignition burner assembly. The flame detector device is installed inside the flame detector installation pipe 4 to facilitate observing the flame conditions of the ignition burner and the low-calorific value gas burner. The specific angle of this embodiment is: 3.8°.

[0049] Comparative Example 1:

[0050] The difference between this comparative example and Embodiment 1 is that along the axial direction, the wet gas tank 5, the dry gas tank 21, and the combustion chamber 10 are connected and assembled in sequence, and the combustion chamber 10 passes through the dry gas tank and is connected to the partition plate 19. The combustion-supporting gas tank is arranged between the wet gas tank and the dry gas tank and surrounds the outer circumference of the combustion chamber. A plurality of air distribution holes are provided on the combustion chamber and communicate with the inside of the combustion-supporting gas tank, and the plurality of air distribution holes are evenly distributed around the circumference. Air enters the combustion chamber through the air inlet and the air distribution holes.

[0051] After using the fluent software for simulation analysis, the simulation results of the burner in this comparative example are shown in Figure 5 , after using the combustion-supporting air distributor, the air distribution is uniform but the air flow resistance is 7.6 kPa (the process requirement is not more than 4.7 kPa), while the air resistance of the burner in Embodiment 1 is: 1.9 kPa.

[0052] Comparative Example 2:

[0053] The difference between this comparative example and the embodiment is that the ends of each nozzle are closed, and no central spray holes are provided on the end walls. Compared with the burner in Embodiment 1, there is a flow stagnation area at the ends of the nozzles, which is prone to blockage.

[0054] Comparative Example 3:

[0055] The difference between this comparative example and Example 1 is that there is no dry gas nozzle, the dry gas tank is located inside the combustion chamber, and an annular dry gas cavity is formed between the outer wall of the dry gas tank and the inner wall of the combustion chamber. A circle of small spray holes 24 (about 90) are evenly arranged along the circumference on the closing plate at the outlet end of the annular dry gas cavity. See Figure 6 as shown. After use, compared with the burner in Example 1, the dry gas nozzle of the burner in this comparative example is in the furnace, and it is prone to ablation damage when the dry gas flow fluctuates.

[0056] Example 2:

[0057] Using the boiler equipped with the above example to treat wet gas and dry gas, see Figure 7 as shown. The process method is as follows: The wet gas generated by the production device of the coal chemical enterprise enters the separation tank for mixing. After separating the liquid and solid impurities in the gas, it is sent to the low calorific value gas burner of the present invention in the boiler and enters the furnace for combustion. The condensate generated by the separation tank is sent to the flare system separation tank using a condensate pump; after being purified again, it can be used as process cooling water or equipment flushing water, etc.;

[0058] The generated dry gas is directly sent to the burner of the present invention in the boiler through an independent pipeline and enters the furnace for combustion.

[0059] To avoid adverse effects on the original combustion flow field of the boiler, the burner of the present invention newly added in the boiler is arranged between the upper secondary air inlet and the lower SOFA air inlet of the boiler. Specifically, it is installed in the boiler through a protective sleeve assembly, where the protective sleeve assembly consists of a protective sleeve 20 and a connecting flange 22. The protective sleeve assembly is installed at the position between the upper secondary air inlet and the lower SOFA air inlet of the boiler. The burner of the present invention is installed on the protective sleeve assembly and fixed with bolts and nuts through the installation flange 17 and the connecting flange 22, which facilitates the disassembly and maintenance of the low calorific value gas burner.

[0060] Specifically, using the process of this example to treat the discharged waste gas wet gas (including the expansion gas of the methanol synthesis unit, the non-permeating gas of the methanol synthesis unit, and the non-condensable gas of the conversion unit, the wet gas discharge volume is about 5814 Nm 3 / h) and dry gas (the non-condensable gas from the methanol rectification unit, the dry gas discharge volume is about 900 Nm 3 / h) of a certain chemical enterprise. The average calorific value of the above discharged waste gas is about 8857 KJ / Nm 3 .

[0061] In the process, the excess air coefficient of the air flow in the central area of the flame tube of the burner of the present invention is 0.7 (negative oxygen), and the excess air coefficient of the air flow in the peripheral area is 1.25 (oxygen-rich). The central area and the peripheral area are provided with a first-stage swirl vane group and a second-stage swirl vane group, and the swirl intensity is 0.9.

[0062] After detection, the NOx generated in the process is < 300 mg / Nm 3 , and it is estimated that the annual reduction of flare waste gas emissions can be about 4538.4×10 4 m 3 , and the annual reduction of raw coal consumption by the boiler is about 17176 t.

Claims

1. A low calorific value gas burner, characterized in that: It comprises a wet gas box (5), a combustion-supporting gas box (7), a dry gas box (21) and a flame tube (10); the wet gas box is provided with a wet gas inlet (6), the combustion-supporting gas box is provided with a combustion-supporting gas inlet (18), and the dry gas box is provided with a dry gas inlet (9); The wet gas box, combustion-supporting gas box, dry gas box and flame tube are arranged in sequence along the axial direction, and the flame tube passes through the dry gas tube and is connected with the combustion-supporting gas box, and a dry gas cavity is formed between the flame tube and the dry gas box; An inner cylinder (11) is installed in the flame cylinder, and the inner cylinder and the flame cylinder are coaxial; a plurality of primary swirl sheets (15) are installed in the inner cylinder, and a plurality of secondary swirl sheets (16) are installed between the inner cylinder and the flame cylinder; The flame tube is provided with a plurality of through holes at a location located in the dry gas cavity; each through hole is connected to a dry gas nozzle (14), and the dry gas nozzle extends into the flame tube along the axial direction and is located at the outer periphery of the inner tube; one end of the dry gas nozzle is connected to the dry gas cavity through the corresponding through hole, and a plurality of injection holes A are opened in the other axial end area; The axial end wall of the wet gas box is connected with a plurality of primary wet gas nozzles (13) and a plurality of secondary wet gas nozzles (12), wherein the plurality of primary wet gas nozzles are distributed in the central area of ​​the axial end wall of the wet gas box, and extend axially into the flame tube and pass through the inner tube; the plurality of secondary wet gas nozzles are distributed around the plurality of primary wet gas nozzles, and extend axially into the flame tube and are located at the outer periphery of the inner tube; the axial end area of ​​each primary wet gas nozzle passing through the inner tube is provided with a plurality of jet holes B, and the axial end area of ​​each secondary wet gas nozzle away from the wet gas box is provided with a plurality of jet holes C; Along the axial direction, the inner tube, the tube wall area where the jet holes B are distributed, the tube wall area where the jet holes C are distributed, and the tube wall area where the jet holes A are distributed are arranged in sequence.

2. The low calorific value gas burner according to claim 1, characterized in that: Along the circumferential direction, the dry gas nozzle and the secondary wet gas nozzle are distributed at intervals along the circumferential direction.

3. The low calorific value gas burner according to claim 1, characterized in that: Along the circumferential direction, the dry gas nozzle and the secondary wet gas nozzle are distributed at intervals along the circumferential direction, and a single dry gas nozzle is arranged between the multiple secondary wet gas nozzles.

4. The low calorific value gas burner according to claim 1, characterized in that: The end side wall of the dry gas nozzle is evenly distributed with a plurality of jet holes A, and the end wall is provided with jet holes A; the end side wall of the first-stage wet gas nozzle is evenly distributed with a plurality of jet holes B, and the end wall is provided with jet holes B; the end side wall of the second-stage wet gas nozzle is evenly distributed with a plurality of jet holes C, and the end wall is provided with jet holes C.

5. The low calorific value gas burner according to claim 1, characterized in that: The end wall of the dry gas nozzle is provided with an injection hole A; the end wall of the first-stage wet gas nozzle is provided with an injection hole B; and the end wall of the second-stage wet gas nozzle is provided with an injection hole C.

6. The low calorific value gas burner according to claim 1, characterized in that: It also includes an igniter installation tube, which passes through the wet gas box, the combustion-supporting gas box, the dry gas box and the flame tube in sequence along the axial direction and extends into the inner tube; the multiple primary swirl sheets (15) are installed on the igniter installation tube.

7. The low calorific value gas burner according to claim 6, characterized in that: It also includes a fire detection installation tube, which passes through the wet gas box, the combustion-supporting gas box, the dry gas box and the flame tube in axial order, and extends into the inner tube and is located beside the igniter installation tube. At the same time, the axis of the fire detection installation tube and the axis of the igniter installation tube form an angle of 3° to 5°.

8. A waste gas recovery process, using a boiler to burn wet gas and dry gas, characterized in that: The boiler is installed with the burner described in claim 1, and the burner is arranged between the secondary air inlet and the lower SOFA air inlet of the boiler; the wet gas enters the liquid separator tank for mixing, and the liquid and solid impurities in the gas are separated and then sent to the low calorific value gas burner in the boiler for combustion; the dry gas is sent to the low calorific value gas burner in the boiler for combustion.

9. The waste gas recovery process according to claim 8, characterized in that: The liquid separated from the liquid separator is sent to the separator of the flare system.

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