Pyrolysis equipment flue gas waste heat utilization system

Abstract

The application discloses a pyrolysis equipment flue gas waste heat utilization system and relates to the technical field of pyrolysis equipment. The pyrolysis equipment flue gas waste heat utilization system comprises a pyrolysis furnace, a burner, a flue gas outlet, a flue gas outlet pipeline and a gas uniform distribution device.

Description

Technical Field

[0001] This invention relates to the field of pyrolysis equipment technology, and in particular to a waste heat utilization system for flue gas from pyrolysis equipment. Background Technology

[0002] In existing technologies, burners employ flue gas recirculation technology, primarily to dilute the oxygen content in the combustion air, reduce nitrogen oxide emissions, improve combustion efficiency, and save fuel. However, there is currently no application of using recirculated flue gas to balance furnace temperature distribution, protect the furnace inner wall, or reduce furnace heat loss. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a waste heat recovery system for flue gas from pyrolysis equipment, which can utilize the waste heat from the flue gas during the pyrolysis process of the pyrolysis furnace, thereby improving economic efficiency.

[0004] A waste heat recovery system for flue gas from pyrolysis equipment according to an embodiment of the present invention includes:

[0005] A pyrolysis furnace, wherein the pyrolysis furnace is provided with a combustion chamber, and the combustion chamber is provided with a flue gas outlet;

[0006] A burner for heating the combustion chamber to a specific temperature;

[0007] A flue pipe, wherein the flue pipe is connected to the flue gas outlet;

[0008] A gas distribution device is provided in the combustion chamber. The gas distribution device has an outlet surface. The gas discharged from the outlet surface can form a gas film, which covers the inner wall surface of the combustion chamber.

[0009] The first flue gas return pipeline is connected to the gas distribution device through the first flue gas return pipeline.

[0010] The waste heat recovery system for pyrolysis equipment according to embodiments of the present invention has at least the following beneficial effects: the burner heats the combustion chamber to a temperature sufficient for the pyrolysis reaction. High-temperature flue gas generated during pyrolysis is discharged from the flue gas outlet, and a portion of this high-temperature flue gas is fed into a gas distribution device via a first flue gas return pipe, which uniformly introduces the high-temperature flue gas into the combustion chamber. First, the introduction of high-temperature flue gas into the combustion chamber reduces fuel consumption. Second, the temperature of the high-temperature flue gas is much lower than the furnace temperature. Discharged from the outlet surface, the high-temperature flue gas forms a "gas film" on the inner wall surface of the combustion chamber. This "gas film" isolates the direct heating of the combustion chamber wall by the burner, thereby reducing the temperature of the combustion chamber wall and protecting it. It significantly reduces the final exhaust volume, decreasing emissions of carbon dioxide, dust, etc. Flue gas recirculation effectively reduces the oxygen content and nitrogen oxide generation in the exhaust.

[0011] According to some embodiments of the present invention, the flue gas outlet pipeline includes an air heat exchanger, the air heat exchanger includes a flue gas inlet, a cold air inlet, a flue gas outlet and a hot air outlet, the flue gas inlet and the flue gas outlet are connected, the cold air inlet is connected to a heat exchange fan, and the first flue gas return pipeline is connected to the flue gas outlet and the hot air outlet.

[0012] According to some embodiments of the present invention, the combustion chamber is provided with a high-temperature section and a low-temperature section in sequence from the burner to the flue gas outlet. The first flue gas return pipeline includes a low-temperature flue gas return pipeline and a high-temperature flue gas return pipeline. The flue gas outlet is connected to the low-temperature section of the combustion chamber through the high-temperature flue gas return pipeline. The exhaust port and the hot air outlet are connected to the high-temperature section of the combustion chamber through the low-temperature flue gas return pipeline.

[0013] According to some embodiments of the present invention, a second flue gas return pipeline is further included, wherein the furnace wall of the pyrolysis furnace is provided with an air jacket, and at least one of the hot air outlet and the flue gas outlet is connected to the air jacket through the second flue gas return pipeline.

[0014] According to some embodiments of the present invention, the gas distribution device includes a plurality of air distribution ducts arranged in the combustion chamber from the burner to the flue gas outlet, the air distribution ducts being embedded in the furnace wall of the combustion chamber, and the air distribution ducts having air distribution openings facing the combustion chamber.

[0015] According to some embodiments of the present invention, the air outlet is connected to an air distribution cap.

[0016] According to some embodiments of the present invention, the air jacket is arched and extends from one end of the pyrolysis furnace to the other end.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0019] Figure 1 This is a schematic diagram of the structure of a waste heat recovery system for flue gas from a pyrolysis equipment according to an embodiment of the present invention.

[0020] Figure 2 This is a cross-sectional view of a pyrolysis furnace according to the first embodiment of the present invention;

[0021] Figure 3 This is a cross-sectional view of a pyrolysis furnace according to a second embodiment of the present invention.

[0022] Icon labels:

[0023] Pyrolysis furnace 100; Combustion chamber 101; Flue gas outlet 102; Air jacket 103; High-temperature section of combustion chamber 104; Low-temperature section of combustion chamber 105;

[0024] Burner 200;

[0025] Gas distribution device 300; air distribution duct 310; air distribution cap 320;

[0026] First flue gas return pipe 400; Low temperature flue gas return pipe 410; High temperature flue gas return pipe 420.

[0027] Second flue gas return pipeline 500;

[0028] Smoke outlet duct 600; air heat exchanger 610; heat exchange fan 620. Detailed Implementation

[0029] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0030] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0031] In the description of this invention, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features or their sequential relationship.

[0032] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0033] Reference Figure 1 and Figure 2 As shown, this invention discloses a waste heat recovery system for flue gas from pyrolysis equipment, comprising:

[0034] The pyrolysis furnace 100 is provided with a combustion chamber 101 and a flue gas outlet 102.

[0035] Burner 200 is used to heat the combustion chamber 101 to a certain temperature;

[0036] Smoke outlet pipe 600 is connected to smoke outlet 102;

[0037] A gas distribution device 300 is installed inside the combustion chamber 101. The gas distribution device 300 has an outlet surface. The gas discharged from the outlet surface can form a gas film, which covers the inner wall surface of the combustion chamber 101.

[0038] The first flue gas return pipe 400 and the flue gas outlet pipe 600 are connected to the gas distribution device 300 through the first flue gas return pipe 400.

[0039] In this embodiment, the burner 200 heats the combustion chamber 101 to a temperature that allows the combustion chamber 101 to undergo a pyrolysis reaction. The burner 200 specifically includes a gas supply device and a gas nozzle. The gas nozzle is disposed in the combustion chamber 101, and combustion heating is achieved by igniting the gas ejected from the gas nozzle.

[0040] The high-temperature flue gas generated during pyrolysis is discharged from the flue gas outlet 102. A portion of the high-temperature flue gas is sent to the gas distribution device 300 through the first flue gas return pipe 400, and the gas distribution device 300 evenly introduces the high-temperature flue gas into the combustion chamber 101. Firstly, introducing the high-temperature flue gas into the combustion chamber 101 can reduce the amount of fuel required for the heating process.

[0041] Secondly, although the temperature of the high-temperature flue gas is higher than that of room temperature, it is still much lower than that of the furnace. After the high-temperature flue gas is discharged from the outlet, it can form a "gas film" on the inner wall surface of the combustion chamber 101. The "gas film" covering the inner wall surface of the combustion chamber 101 can isolate the direct heating of the inner wall of the combustion chamber 101 by the burner 200, thereby reducing the temperature of the inner wall of the combustion chamber 101 and achieving the purpose of protecting the inner wall of the combustion chamber 101.

[0042] Reference Figure 1 and Figure 2 As shown, in some embodiments of the present invention, the flue gas duct 600 includes an air heat exchanger 610, which includes a flue gas inlet, a cold air inlet, a flue gas outlet, and a hot air outlet. The flue gas inlet and the flue gas outlet 102 are connected. The cold air inlet is connected to a heat exchange fan 620. The first flue gas return duct 400 is connected to the flue gas outlet and the hot air outlet.

[0043] In this embodiment, the high-temperature flue gas discharged from the flue gas outlet 102 is sent into the air heat exchanger 610, while the outside cold air enters the air heat exchanger 610 through the cold air inlet. In the air heat exchanger 610, the high-temperature flue gas (approximately 350°C) and the cold air exchange heat, causing the high-temperature flue gas to cool down to form low-temperature flue gas (approximately 110°C), while the cold air is heated to become hot air (approximately 160°C). The low-temperature flue gas is discharged from the flue gas outlet, and the hot air is discharged from the hot air outlet. The generated hot air can have numerous uses, such as for heating, achieving the purpose of waste heat utilization.

[0044] In this embodiment, some low-temperature flue gas and hot air are sent into the combustion chamber 101 by the first flue gas return pipe 400. While reducing fuel consumption and forming a "gas film", the supplemented air also serves to provide combustion-supporting air, making the fuel burn more completely.

[0045] It should be noted that in this embodiment, not all low-temperature flue gas and hot air are sent into the combustion chamber 101. Only some low-temperature flue gas and some unused hot air are sent into the combustion chamber 101, and the remaining hot air can be used for other purposes.

[0046] Reference Figure 1 and Figure 2 As shown, in some embodiments of the present invention, the combustion chamber 101 is provided with a high-temperature section 104 and a low-temperature section 105 in sequence from the burner 200 to the flue gas outlet 102. The first flue gas return pipeline 400 includes a low-temperature flue gas return pipeline 410 and a high-temperature flue gas return pipeline 420. The flue gas outlet 102 is connected to the low-temperature section 105 of the combustion chamber through the high-temperature flue gas return pipeline 420. The exhaust port and the hot air outlet are connected to the high-temperature section 104 of the combustion chamber through the low-temperature flue gas return pipeline 410.

[0047] Understandably, within combustion chamber 101, the high-temperature section 104, closer to burner 200, has a higher temperature, while the low-temperature section 105, farther from burner 200, has a lower temperature. The flue gas discharged from flue gas outlet 102 has a higher temperature; the flue gas discharged from exhaust port and the air discharged from hot air outlet have relatively lower temperatures.

[0048] In this embodiment, the flue gas discharged from the flue gas outlet 102 is directly introduced into the low-temperature section 105 of the combustion chamber through the high-temperature flue gas return pipe 420. The flue gas discharged from the exhaust port and the air discharged from the hot air outlet are introduced into the high-temperature section 104 of the combustion chamber through the low-temperature flue gas return pipe 410. By introducing gases of different temperatures into the high-temperature section 104 and the low-temperature section 105 of the combustion chamber 101, a multi-loop, multi-inlet stepped recirculation is formed, making the temperature distribution within the combustion chamber 101 more balanced. Furthermore, the recirculation flow rates of the low-temperature flue gas return pipe 410, the high-temperature flue gas return pipe 420, and the second flue gas return pipe 500 can be automatically adjusted according to the load and temperature requirements of the combustion chamber 101.

[0049] Reference Figure 1 and Figure 2 As shown, in some embodiments of the present invention, a second flue gas return pipe 500 is also included. The furnace wall of the pyrolysis furnace 100 is provided with an air jacket 103. At least one of the hot air outlet and the flue gas outlet is connected to the air jacket 103 through the second flue gas return pipe 500.

[0050] In this embodiment, hot air discharged from the hot air outlet and flue gas discharged from the exhaust port are introduced into the air jacket 103 through the second flue gas return pipe 500, forming an airflow jacket in the air jacket 103. The airflow jacket acts as an insulation layer, reducing heat loss from the combustion chamber 101. During operation, flue gas and hot air are continuously fed into the air jacket 103 to maintain its temperature and prevent it from dropping.

[0051] Because the hot air in the air jacket 103 is at a high temperature, it can heat the pyrolysis furnace 100, reducing heat loss due to heat conduction. Secondly, the air jacket 103, relative to the solid furnace wall, has good thermal insulation properties, further reducing heat loss. Specifically, the hot air is primarily obtained through heat exchange and heat recovery from the flue gas generated during the pyrolysis reaction in the pyrolysis furnace 100, thus avoiding additional heat loss.

[0052] It should be noted that in this embodiment, the flue gas generated in the pyrolysis furnace combustion chamber is not directly introduced into the air jacket 103. Instead, heated air is introduced into the air jacket 103 after passing through the air heat exchanger 610. The purpose is that, in addition to using natural gas as the main fuel, the pyrolysis furnace combustion chamber also utilizes pyrolysis gas generated from the pyrolysis reaction within the pyrolysis cylinder as auxiliary fuel. The flue gas produced after the combustion of the pyrolysis gas has a complex composition, containing numerous soot particles, tar gases, etc. If the high-temperature flue gas is directly introduced into the air jacket 103, soot particles, tar, and other components will adhere to the inner wall of the air jacket 103, causing contamination. Furthermore, removing the soot particles and tar adhering to the inner wall of the air jacket 103 is very difficult. Heated air, on the other hand, is relatively clean and does not present the aforementioned problems.

[0053] Reference Figure 1 and Figure 2 As shown, in some embodiments of the present invention, the gas distribution device 300 includes a plurality of air distribution pipes 310. The air distribution pipes 310 are arranged in the combustion chamber 101 from the burner 200 to the flue gas outlet 102. The air distribution pipes 310 are U-shaped and are embedded in the furnace wall of the combustion chamber 101. The air distribution pipes 310 are provided with air distribution ports facing the combustion chamber 101.

[0054] In this embodiment, the gas distribution device 300 consists of several air distribution pipes 310. The air distribution pipes 310 are U-shaped and embedded in the furnace wall of the combustion chamber 101. The air outlet surfaces of the air distribution pipes 310 include those on the two side walls of the combustion chamber 101 and the bottom surface of the combustion chamber 101. The gas discharged from each outlet surface can evenly distribute throughout the entire combustion chamber 101, ensuring temperature uniformity in all areas within the combustion chamber 101. The gas discharged from each outlet surface can form a "gas film," which separates the combustion chamber wall of the combustion chamber 101 from the combustion flame inside the furnace. This makes the temperature of the combustion chamber wall of the combustion chamber 101 close to the temperature of the "gas film," while the temperature of the "gas film" is much lower than the temperature of the combustion flame in the combustion chamber 101. Therefore, the temperature of the combustion chamber wall of the combustion chamber 101 is relatively low, achieving the purpose of protecting the pyrolysis furnace 100.

[0055] Reference Figure 1 and Figure 2 As shown, in some embodiments of the present invention, the air outlet surface of the air distribution duct 310 is flush with the furnace wall of the combustion chamber 101. This allows the "air film" to fit as closely as possible to the furnace wall of the combustion chamber 101, ensuring a protective effect on the furnace wall of the combustion chamber 101.

[0056] In particular, the air vent is connected to an air distribution cap 320, which makes the gas discharged from the air vent fill the combustion chamber 101 more evenly.

[0057] Reference Figure 1 and Figure 2 As shown, in some embodiments of the present invention, the air jacket 103 is arched and extends from one end of the pyrolysis furnace 100 to the other. The arched shape of the air jacket 103 can protect the side walls of the combustion chamber 101 and the furnace roof.

[0058] The waste heat recovery system for pyrolysis equipment of this invention can significantly reduce the final flue gas volume, thereby reducing emissions of carbon dioxide, dust, and other pollutants. Flue gas recirculation can effectively reduce the oxygen content and nitrogen oxide generation in the flue gas.

[0059] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A waste heat recovery system for flue gas from pyrolysis equipment, characterized in that, include: A pyrolysis furnace, wherein the pyrolysis furnace is provided with a combustion chamber, and the combustion chamber is provided with a flue gas outlet; A burner for heating the combustion chamber to a specific temperature; A flue pipe, wherein the flue pipe is connected to the flue gas outlet; A gas distribution device is provided in the combustion chamber. The gas distribution device has an outlet surface. The gas discharged from the outlet surface can form a gas film, which covers the inner wall surface of the combustion chamber. The first flue gas return pipeline, wherein the flue gas outlet pipeline is connected to the gas distribution device through the first flue gas return pipeline; The gas distribution device includes several air distribution pipes, which are arranged in the combustion chamber from the burner to the flue gas outlet. The air distribution pipes are embedded in the furnace wall of the combustion chamber and have air distribution openings facing the combustion chamber.

2. The waste heat recovery system for pyrolysis equipment flue gas according to claim 1, characterized in that: The flue gas outlet pipeline includes an air heat exchanger, which includes a flue gas inlet, a cold air inlet, a flue gas outlet, and a hot air outlet. The flue gas inlet and the flue gas outlet are connected together. The cold air inlet is connected to a heat exchange fan. The first flue gas return pipeline is connected to the flue gas outlet and the hot air outlet.

3. The waste heat recovery system for pyrolysis equipment flue gas according to claim 2, characterized in that: The combustion chamber is provided with a high-temperature section and a low-temperature section in sequence from the burner to the flue gas outlet. The first flue gas return pipeline includes a low-temperature flue gas return pipeline and a high-temperature flue gas return pipeline. The flue gas outlet is connected to the low-temperature section of the combustion chamber through the high-temperature flue gas return pipeline. The exhaust port and the hot air outlet are connected to the high-temperature section of the combustion chamber through the low-temperature flue gas return pipeline.

4. The waste heat recovery system for pyrolysis equipment flue gas according to claim 2, characterized in that: It also includes a second flue gas return pipeline, the furnace wall of the pyrolysis furnace is provided with an air jacket, and at least one of the hot air outlet and the flue gas outlet is connected to the air jacket through the second flue gas return pipeline.

5. The waste heat recovery system for pyrolysis equipment flue gas according to claim 1, characterized in that: The air distribution outlet is connected to an air distribution cap.

6. The waste heat recovery system for pyrolysis equipment flue gas according to claim 4, characterized in that: The air interlayer is arched and extends from one end of the pyrolysis furnace to the other.

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