Combination burner for treating resin carbonization pyrolysis gas incinerator

Abstract

This invention discloses a combined burner for treating resin carbonization pyrolysis gas incinerators, belonging to the field of industrial waste gas incineration technology. It adopts a coaxial nested structure, with the pyrolysis gas burner positioned inside the center of the natural gas burner, both sharing a common combustion air system. The pyrolysis gas channel remains completely isolated from the combustion air, and its inner wall is covered with a high-temperature resistant, anti-coking coating. An annular preheating chamber is formed between the outer side of the natural gas burner and the pyrolysis gas burner, utilizing the waste heat of the natural gas to preheat the pyrolysis gas burner throughout the process. The combustion air, via circumferential branch pipes, mixes and combusts with the pyrolysis gas and natural gas only downstream of the outlet. This invention, through structural integration, complete isolation preheating, and a minimal persistent flame design, overcomes the shortcomings of existing technologies, such as large footprint, high cost, easy clogging, and high natural gas energy consumption. It achieves long-term non-coking and clogging prevention, a reduction of approximately 30% in natural gas consumption, and a VOCs removal rate of ≥99.9%, while also possessing high safety and high thermal efficiency.

Description

Technical Field

[0001] This invention relates to the field of industrial waste gas incineration technology, and in particular to a combined burner for an incinerator containing high-tar pyrolysis gas generated during the resin carbonization process, which is suitable for the harmless and resource-oriented incineration treatment of pyrolysis gas after anaerobic pyrolysis of porous carbon precursors. Background Technology

[0002] Resin carbonization technology is a key process for preparing porous carbon materials. It typically involves using a rotary kiln to perform anaerobic pyrolysis of the resin-based carbon source material. This pyrolysis process generates a large amount of high-temperature pyrolysis gas. The main components of this pyrolysis gas are moisture, nitrogen, non-condensable gases, and tar, with tar accounting for over 50%. The temperature is usually between 300℃ and 450℃. This gas is characterized by high temperature, high tar content, easy condensation and coking, and high dust content. Direct emission would cause serious environmental pollution, necessitating high-temperature oxidation treatment in an incinerator.

[0003] In existing technologies, for the incineration of pyrolysis gas containing tar, incinerators generally employ two independent burners: one set dedicated to pyrolysis gas and the other dedicated to natural gas. Each set of burners is equipped with its own independent combustion air system. The natural gas burner provides the initial heat source for heating the incinerator and the open flame during operation, thus avoiding the risk of flameout and flash explosion caused by direct contact between the pyrolysis gas and the low-temperature furnace. The pyrolysis gas burner is used to pre-mix the pyrolysis gas with the combustion air before sending it into the furnace for combustion.

[0004] The existing technology has the following significant drawbacks: 1. Large footprint, inconvenient layout, and high equipment cost: Two independent burners and two independent combustion air systems occupy a large space on the end face of the incinerator, resulting in high equipment investment and operation and maintenance costs; 2. Pyrolysis gas burners are prone to clogging: Pyrolysis gas containing high tar is premixed with ambient temperature combustion air before entering the furnace, causing the temperature of the pyrolysis gas to drop sharply, and the tar to condense and coke. Long-term operation can easily cause burner clogging, affecting the stable operation of the system. 3. High operating costs of natural gas: Due to space constraints, the two independent burners cannot be arranged compactly. In order to ensure stable contact between the pyrolysis gas and the outer flame of the natural gas pilot flame, the natural gas burners need to be kept in a high-fire pilot flame state, which increases the natural gas consumption by about 30% compared to the minimum demand, resulting in high operating costs. 4. Poor combustion stability and low VOCs removal rate: Pre-mixing of pyrolysis gas with air can easily lead to incomplete combustion, making it difficult to consistently meet environmental emission requirements for VOCs removal. Summary of the Invention

[0005] The purpose of this invention is to provide a combined burner for treating resin carbonization pyrolysis gas incinerators, aiming to overcome the shortcomings of existing technologies where two independent burners occupy a large area, are costly, are prone to clogging, and have high natural gas energy consumption. This invention achieves integrated structure, low energy consumption during operation, long-term non-clogging, and stable and efficient combustion, thus meeting the requirements for harmless incineration treatment of resin carbonization pyrolysis gas.

[0006] The objective of this invention is achieved through the following technical solution: A combined burner for processing resin carbonization pyrolysis gas incinerator includes a natural gas burner, a pyrolysis gas burner, a combustion air system, and a refractory shell; The natural gas burner and the pyrolysis gas burner adopt a coaxial nested structure. The pyrolysis gas burner is coaxially arranged on the inner side of the center of the natural gas burner, and the natural gas burner is arranged around the outer side of the pyrolysis gas burner. Their center lines coincide and their outlet ends converge in the same combustion zone in the incinerator. The pyrolysis gas burner has a hollow tubular structure with a pyrolysis gas channel inside. The inlet end of the pyrolysis gas channel is connected to a resin carbonized pyrolysis gas delivery pipe, and the outlet end extends to the center of the flame zone of the natural gas burner. The pyrolysis gas channel does not come into contact with the combustion air throughout its entire length. The natural gas burner has a ring-shaped hollow structure and is fitted on the outside of the pyrolysis gas burner. A natural gas channel is formed inside the burner, and a ring-shaped flame zone is formed at its outlet end. An annular preheating chamber is formed between the outer wall of the natural gas burner and the outer wall of the pyrolysis gas burner. The annular preheating chamber uses the waste heat from natural gas combustion to preheat the pyrolysis gas burner throughout the process. The combustion air system is shared by the natural gas burner and the pyrolysis gas burner, and includes a main combustion air inlet, a combustion air jacket, and multiple combustion air branch pipes. The combustion air jacket is an annular cavity located between the outer shell of the natural gas burner and the inner wall of the refractory shell, used to transport combustion air. The combustion air branch pipes are evenly arranged circumferentially at the outlet end of the natural gas burner, with their outlets facing the mixing area of ​​the pyrolysis gas and the natural gas flame. The shared combustion air system is configured such that the combustion air enters the combustion area only downstream of the outlet of the natural gas burner and after the pyrolysis gas is ejected, through the combustion air branch pipes, to achieve ternary mixed combustion of combustion air, pyrolysis gas, and natural gas. The refractory shell tightly covers the natural gas burner and the combustion air jacket.

[0007] As a further improvement of the present invention, the inner wall surface of the pyrolysis gas channel is covered with a high-temperature resistant and anti-coking composite coating.

[0008] As a further improvement of the present invention, the high-temperature resistant anti-coking composite coating uses alumina-silicon carbide as the substrate.

[0009] As a further improvement of the present invention, the pyrolysis gas originates from the resin anaerobic carbonization process, wherein the tar mass ratio is not less than 50%, and the temperature of the pyrolysis gas itself is 300℃~450℃; the designed flow rate of the pyrolysis gas in the pyrolysis gas channel is 8 m / s~12 m / s.

[0010] As a further improvement of the present invention, the annular preheating chamber maintains the preheating temperature of the pyrolysis gas burner at 250°C to 350°C.

[0011] As a further improvement of the present invention, the refractory shell is integrally cast using corundum-mullite refractory castable, and its maximum withstand temperature is not less than 1400℃.

[0012] As a further improvement of the present invention, the method of using the above-mentioned combined burner includes the following steps: Start the natural gas burners to heat the furnace at high flame, raising the temperature inside the incinerator to 850℃±50℃; Switch the natural gas burner to the minimum pilot light position and adjust the air volume of the public combustion air system; Turn on the pyrolysis gas burner and inject tar-containing pyrolysis gas at 300℃~450℃ into the furnace, so that it comes into direct contact with the natural gas pilot flame. Combustion air is injected into the area downstream of the natural gas burner outlet through the combustion air branch pipe, where it mixes and burns with pyrolysis gas and natural gas.

[0013] As a further improvement of the present invention, it also includes a temperature control step: When the furnace temperature is below 850℃, the flow rate of the natural gas burner is automatically increased; When the furnace temperature exceeds 1100℃, the natural gas flow rate will be automatically reduced and the combustion air volume will be increased. When the pyrolysis gas temperature is below 300℃ or an abnormal supply occurs, the pyrolysis gas valve will be automatically shut off, and the system will switch to natural gas independent combustion mode.

[0014] As a further improvement of the present invention, the pyrolysis gas is high-tar pyrolysis gas, wherein the tar mass ratio is ≥50%; the residence time of the pyrolysis gas in the furnace is controlled to be ≥2s, so as to maintain the furnace temperature at 850℃~1100℃ and achieve a VOCs removal rate of ≥99.9%.

[0015] The above technical solution has the following beneficial effects: 1. High structural integration and reduced cost: The pyrolysis gas burner and the natural gas burner adopt a coaxial nested two-in-one design and share a set of combustion air system. Compared with the split layout, the equipment occupies about 50% less space, which greatly reduces the space occupied on the incinerator end face and reduces equipment investment and operation and maintenance costs.

[0016] 2. Full-process anti-clogging and reliable operation: The pyrolysis gas channel is never in contact with ambient temperature combustion air, eliminating the temperature drop caused by premixing; at the same time, the waste heat of the natural gas burner is used to preheat the pyrolysis gas burner in a ring (250℃~350℃), combined with the high temperature resistant and anti-coking composite coating on the inner wall, ensuring that the high tar (≥50%) pyrolysis gas does not condense and coke during transportation, fundamentally solving the burner clogging problem. Attached Figure Description

[0017] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0018] The structures, proportions, sizes, etc. shown in this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0019] Figure 1 This is a schematic diagram of the structure of the present invention applied to an incinerator.

[0020] Figure 2 This is a schematic diagram of the structure provided by the present invention.

[0021] Figure 3 This is a schematic diagram of the internal structure of the combustion-supporting air interlayer provided by the present invention.

[0022] Figure 4 This is a front view structural diagram provided by the present invention.

[0023] Figure 5 This is a schematic diagram of the model structure provided by the present invention.

[0024] In the picture: 1. Incinerator; 2. Pyrolysis gas burner; 3. Natural gas burner; 4. Combustion air main inlet; 5. Combustion-supporting air branch pipe; 6. Combustion-supporting air interlayer; 7. Refractory shell. Detailed Implementation

[0025] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0026] like Figures 1-5 As shown, a combined burner for processing resin carbonization pyrolysis gas incinerator includes a natural gas burner 3, a pyrolysis gas burner 2, a combustion air system, and a refractory shell 7. The combined burner, consisting of the natural gas burner 3 and the pyrolysis gas burner 2, has a coaxial nested structure. The pyrolysis gas burner 2 is coaxially arranged inside the center of the natural gas burner 3, and the natural gas burner 3 is arranged around the outside of the pyrolysis gas burner 2. The centerlines of the two coincide and converge in the same combustion zone within the incinerator 1. The combustion air system is shared by the natural gas burner 3 and the pyrolysis gas burner 2, eliminating the need for an independent combustion air channel for the pyrolysis gas burner.

[0027] Specifically, the pyrolysis gas burner 2 has a hollow tubular structure with an internal pyrolysis gas channel. The inlet end of the pyrolysis gas channel is connected to a resin-carbonized pyrolysis gas delivery pipe, and the outlet end extends to the center of the flame zone of the natural gas burner 3. The pyrolysis gas channel is completely isolated from ambient temperature combustion air. The inner wall of the pyrolysis gas channel is covered with a high-temperature resistant, anti-coking composite coating based on alumina-silicon carbide to inhibit tar condensation.

[0028] The design flow velocity of the pyrolysis gas in the channel is controlled between 8 m / s and 12 m / s, preferably 10 m / s, to maintain turbulence and prevent dust settling and pipeline blockage. The pyrolysis gas originates from the resin anaerobic carbonization process, the tar content in the medium is not less than 50%, and its own temperature is 300℃~450℃.

[0029] The natural gas burner 3 has a ring-shaped hollow structure and is fitted outside the pyrolysis gas burner 2, forming a natural gas channel inside. The outlet end of the natural gas burner 3 is flush with or slightly shorter than the outlet end of the pyrolysis gas burner 2, forming a ring-shaped flame zone at the outlet. During operation, the natural gas burner maintains a minimum consumption continuous flame state, with the flame directly contacting the pyrolysis gas ejected from the center. A ring-shaped preheating chamber is formed between the outer wall of the natural gas burner 3 and the outer wall of the pyrolysis gas burner 2, utilizing the waste heat from natural gas combustion to preheat the pyrolysis gas burner throughout the process. The preheating temperature is maintained at 250℃~350℃ to prevent the pyrolysis gas from precooling and coking.

[0030] The shared combustion air system includes a main combustion air inlet 4, a combustion air jacket 6, and multiple combustion air branch pipes 5 (three branch pipes are shown in the diagram; the actual number can be adjusted according to requirements). The combustion air jacket 6 is an annular cavity located between the outer shell of the natural gas burner 3 and the inner wall of the refractory shell 7, used to transport ambient temperature combustion air. The combustion air branch pipes 5 are evenly arranged circumferentially at the outlet end of the natural gas burner 3, with the outlet facing the mixing area of ​​pyrolysis gas and natural gas flame. The system is configured such that the combustion air enters the combustion zone only downstream of the outlet of the natural gas burner 3, and after the pyrolysis gas is ejected, it enters the combustion zone through the combustion air branch pipes 5, achieving ternary mixing and combustion with pyrolysis gas and natural gas. During the transportation process, the combustion air jacket 6 can utilize the radiant heat of the furnace body to preheat the combustion air, thereby improving thermal efficiency.

[0031] The refractory shell 7 is integrally cast using refractory castable with excellent high temperature resistance and thermal shock resistance, such as corundum-mullite composite material, which can withstand a maximum temperature of not less than 1400℃. It tightly encapsulates the natural gas burner 3 and the combustion air jacket 6 to ensure the long-term thermal stability of the burner structure.

[0032] The combined burner usage method and control logic provided by this invention are as follows: First, the ignition and heating procedure is executed, starting the natural gas burner 3 and operating it in high-fire mode. Utilizing the heat storage of the refractory shell 7, the furnace temperature of the incinerator 1 is raised to the set range of 850℃±50℃. Subsequently, the natural gas is switched to the minimum load per-flame state, and the reference air volume of the public combustion air system is adjusted through the main combustion air inlet 4.

[0033] Next, the pyrolysis gas burner 2 is turned on, and the pyrolysis gas, which is 300℃ to 450℃ and rich in tar, is injected through an independent channel and directly enters the high-temperature zone of the outer flame of the natural gas pilot flame. At the same time, the combustion air is injected into the mixing area through the circumferentially arranged combustion air branch pipes 5, forming a flame diffusion combustion.

[0034] The system is equipped with a closed-loop temperature control strategy: when the furnace temperature is below 850℃, the controller automatically increases the natural gas flow to supplement heat; when the temperature exceeds 1100℃, it automatically reduces the natural gas load and correspondingly increases the combustion air volume. If abnormal pyrolysis gas parameters are detected (such as temperature <300℃ or pressure fluctuations), the system will immediately shut off the pyrolysis gas valve and force a switch to independent natural gas combustion mode to prevent low-temperature coking and blockage. Through the above control, the furnace temperature is ensured to be stable between 850℃ and 1100℃, and the effective residence time of the pyrolysis gas is not less than 2 seconds, ultimately achieving a purification index of VOCs removal rate ≥99.9%.

[0035] This invention, based on the three elements of combustion (temperature, fuel, and oxygen), addresses the specific operating conditions of resin carbonization pyrolysis gas where tar content is ≥50%, temperature is between 300℃ and 450℃, and coking is prone to occur. It employs a holistic, collaborative design scheme of "coaxial nested structure + shared combustion air + full-process preheating + outlet post-mixing + minimal persistent flame." Specifically, the natural gas burner 3 provides full-process thermal radiation preheating to the centrally located pyrolysis gas burner 2, ensuring that the pyrolysis gas does not experience temperature drop and coking during transport. The pyrolysis gas is physically isolated from the ambient temperature combustion air before entering the furnace, only coming into contact with and mixing with the combustion air downstream of the natural gas burner 3 outlet, thus ensuring combustion stability. Simultaneously, the natural gas burner 3 maintains only a minimum load persistent flame, directly contacting and igniting the pyrolysis gas, reducing overall energy consumption, and avoiding the risk of flash explosion from premixed high-concentration combustible gases, ultimately achieving a comprehensive effect of anti-clogging, energy saving, and efficient combustion.

[0036] In summary, the embodiments of the present invention achieve the following technical effects: 1. High structural integration and reduced cost: The pyrolysis gas burner and the natural gas burner adopt a coaxial nested two-in-one design and share a set of combustion air system. Compared with the split layout, the equipment occupies about 50% less space, which greatly reduces the space occupied on the incinerator end face and reduces equipment investment and operation and maintenance costs.

[0037] 2. Full-process anti-clogging and reliable operation: The pyrolysis gas channel is never in contact with ambient temperature combustion air, eliminating the temperature drop caused by premixing; at the same time, the waste heat of the natural gas burner is used to preheat the pyrolysis gas burner in a ring (250℃~350℃), combined with the high temperature resistant and anti-coking composite coating on the inner wall, ensuring that the high tar (≥50%) pyrolysis gas does not condense and coke during transportation, fundamentally solving the burner clogging problem.

[0038] 3. Low energy consumption and low operating costs: The natural gas burner only needs to maintain a very low load of continuous flame (reducing natural gas consumption by about 30% compared to existing technologies). It uses the annular flame to directly ignite the pyrolysis gas ejected from the center, without the need to maintain a large flame to ensure mixing, which significantly saves operating costs.

[0039] 4. High efficiency and environmental compliance: The pyrolysis gas is mixed with the combustion air only after it is injected, avoiding the phenomenon of incomplete combustion due to premixing; with furnace temperature control of 850℃~1100℃ and an effective residence time of ≥2 seconds, the VOCs removal rate can reach more than 99.9%, stably meeting the environmental emission standards.

[0040] 5. Eliminating flash explosion risk and improving thermal efficiency: Pyrolysis gas and combustion air are completely physically isolated before entering the furnace, contacting only in the high-temperature flame zone. This avoids the flash explosion hazard caused by premixing high-concentration combustible gases. Furthermore, automatic shut-off protection under abnormal operating conditions ensures high safety. The shared combustion air jacket utilizes the furnace's radiant heat to preheat the combustion air, while the annular preheating chamber recovers waste heat from natural gas combustion, significantly improving overall thermal efficiency.

[0041] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0042] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0043] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A combined burner for processing resin carbonization pyrolysis gas incinerators, characterized in that: Includes natural gas burner (3), pyrolysis gas burner (2), combustion air system and refractory shell (7); The natural gas burner (3) and the pyrolysis gas burner (2) adopt a coaxial nested structure. The pyrolysis gas burner (2) is coaxially arranged on the inner side of the center of the natural gas burner (3). The natural gas burner (3) is arranged around the outer side of the pyrolysis gas burner (2). The center lines of the two coincide and their outlet ends converge in the same combustion area in the incinerator (1). The pyrolysis gas burner (2) is a hollow tubular structure with a pyrolysis gas channel inside. The inlet end of the pyrolysis gas channel is connected to a resin carbonized pyrolysis gas delivery pipe, and the outlet end extends to the center of the flame zone of the natural gas burner (3). The pyrolysis gas channel does not come into contact with the combustion air throughout its entire length. The natural gas burner (3) has an annular hollow structure and is fitted on the outside of the pyrolysis gas burner (2). A natural gas channel is formed inside and an annular flame zone is formed at its outlet end. An annular preheating cavity is formed between the outer wall of the natural gas burner (3) and the outer wall of the pyrolysis gas burner (2). The annular preheating cavity uses the residual heat from natural gas combustion to preheat the pyrolysis gas burner (2) throughout the process. The combustion air system is shared by the natural gas burner (3) and the pyrolysis gas burner (2), and includes a main combustion air inlet (4), a combustion air jacket (6), and multiple combustion air branch pipes (5); the combustion air jacket (6) is an annular cavity located between the outer shell of the natural gas burner (3) and the inner wall of the refractory shell (7), used to transport combustion air; the combustion air branch pipes (5) are evenly arranged circumferentially at the outlet end of the natural gas burner (3), and their outlets face the mixing area of ​​the pyrolysis gas and the natural gas flame; the shared combustion air system is configured such that the combustion air only enters the combustion area through the combustion air branch pipes (5) in the downstream area of ​​the outlet of the natural gas burner (3) and after the pyrolysis gas is ejected, so as to realize the ternary mixed combustion of combustion air, pyrolysis gas and natural gas; The refractory shell (7) tightly covers the natural gas burner (3) and the combustion air jacket (6).

2. The combined burner according to claim 1, characterized in that, The inner wall of the pyrolysis gas channel is covered with a high-temperature resistant and anti-coking composite coating.

3. The combined burner according to claim 2, characterized in that, The high-temperature resistant and anti-coking composite coating uses alumina-silicon carbide as the substrate.

4. The combined burner according to claim 1, characterized in that, The pyrolysis gas originates from the anaerobic carbonization process of the resin, wherein the tar content is not less than 50%, and the temperature of the pyrolysis gas itself is 300℃~450℃; the designed flow rate of the pyrolysis gas in the pyrolysis gas channel is 8 m / s~12 m / s.

5. The combined burner according to claim 1, characterized in that, The annular preheating chamber maintains the preheating temperature of the pyrolysis gas burner (2) at 250℃~350℃.

6. The combined burner according to claim 1, characterized in that, The refractory shell (7) is integrally cast using corundum-mullite refractory castable, and its maximum temperature resistance is not less than 1400℃.

7. The method of using the combined burner according to any one of claims 1 to 6, characterized in that, Includes the following steps: Start the natural gas burner (3) to heat the furnace at high temperature, and heat the temperature inside the incinerator (1) to 850℃±50℃; Switch the natural gas burner (3) to the minimum flame state and adjust the air volume of the public combustion air system; Turn on the pyrolysis gas burner (2) and inject tar-containing pyrolysis gas at 300℃~450℃ into the furnace, so that it comes into direct contact with the natural gas live flame; Combustion air is injected into the area downstream of the natural gas burner (3) through the combustion air branch pipe (5) and mixed with pyrolysis gas and natural gas for combustion.

8. The method of use according to claim 7, characterized in that, It also includes temperature control steps: When the furnace temperature is below 850℃, the flow rate of the natural gas burner (3) is automatically increased; When the furnace temperature exceeds 1100℃, the natural gas flow rate will be automatically reduced and the combustion air volume will be increased. When the pyrolysis gas temperature is below 300℃ or an abnormal supply occurs, the pyrolysis gas valve will be automatically shut off, and the system will switch to natural gas independent combustion mode.

9. The method of use according to claim 7, characterized in that, The pyrolysis gas is high-tar pyrolysis gas, in which the tar content is ≥50% by mass; the residence time of the pyrolysis gas in the furnace is controlled to be ≥2s to maintain the furnace temperature at 850℃~1100℃, so as to achieve a VOCs removal rate of ≥99.9%.

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