Mulching film combustion tail gas treatment device

Abstract

The utility model discloses a mulching film combustion tail gas treatment device which comprises multiple stages of reactors connected in series, a gas inlet of the first-stage reactor communicates with an outlet of an air heater and an outlet of a combustion fan through a three-way valve, and a gas outlet of the last-stage reactor is provided with an exhaust pipe. A first waste gas discharge pipe and a second waste gas discharge pipe are arranged on the exhaust pipe, the reactor is provided with a gas mixing chamber, a catalyst layer and a temperature measuring unit, and a tail gas injection pipe used for injecting mulching film combustion tail gas into the gas mixing chamber is inserted into the gas mixing chamber. The mulching film combustion tail gas treatment method adopts the device and comprises the steps of preheating the mulching film combustion tail gas treatment device, starting the reactor step by step and discharging waste gas. The mulching film combustion tail gas treatment device can reduce the harm of mulching film combustion tail gas treatment to the environment, effectively avoids the damage to the service life of a catalyst due to overhigh local temperature, and ensures the operation stability and the service life of the mulching film combustion tail gas treatment device.

Description

TECHNICAL FIELD

[0001] The utility model relates to agricultural waste treatment technical field, especially relate to a mulching film combustion tail gas treatment device. BACKGROUND

[0002] The mulching film covering planting technology is often used in agriculture to improve the temperature and moisture retention capacity of soil, but the mulching film left in the soil needs hundreds of years to decompose, and if the mulching film is not treated, the residual film will be mixed with the soil to form a hardening layer in the 30cm soil layer of the ploughed surface, which restricts the reproduction capacity of the soil and is not conducive to the normal growth and development of crops, and even pollutes the underground water. In order to treat the waste mulching film, the waste agricultural mulching film is usually treated by incineration, but the tail gas after the mulching film is burned contains harmful substances, and direct discharge of the mulching film combustion tail gas will cause harm to the environment. SUMMARY

[0003] In view of the defects in the prior art, the mulching film combustion tail gas treatment device is provided to solve the technical problems of unstable catalyst in the mulching film combustion tail gas treatment process in the prior art.

[0004] In order to achieve the above-mentioned purpose of the utility model, the technical scheme provided by the utility model is as follows:

[0005] A mulching film combustion tail gas treatment device, comprising a reactor connected in multiple stages in series, one end of the reactor is provided with a gas inlet, the other end of the reactor is provided with a gas outlet, the gas inlet of a first-stage reactor is connected with a three-way valve, the other two inlets of the three-way valve are communicated with the outlet of a hot air fan and the outlet of a combustion air fan respectively, an exhaust pipe is arranged on the gas outlet of the last-stage reactor, a first waste gas discharge pipe and a second waste gas discharge pipe are arranged on the exhaust pipe, and the port of the first waste gas discharge pipe is arranged in an upward open manner;

[0006] The reactor is provided with a mixing chamber and a catalytic layer along the direction of gas flow, the mixing chamber is used for mixing mulch combustion tail gas and air, the mixing chamber is provided with a tail gas injection pipe used for injecting mulch combustion tail gas into the mixing chamber, the catalytic layer is provided with a catalyst used for catalytically oxidizing the mixed gas, the gas inlet is arranged at one end of the mixing chamber, the other end of the mixing chamber is communicated with the catalytic layer, the catalytic layer is communicated with the gas outlet, the temperature measuring unit used for measuring the temperature of the catalyst is arranged above the catalytic layer, the tail gas injection pipe is communicated with the second waste gas discharge pipe, the gas inlet valve is arranged on the tail gas injection pipe, the gas inlet valve is electrically connected with the control system, and the control system adjusts the opening degree of the gas inlet valve according to the temperature monitored by the temperature measuring unit.

[0007] In an embodiment, the mixing chamber is provided with a steel wire mat.

[0008] In an embodiment, the reactor is in the shape of a barrel, the catalyst is in the shape of a honeycomb, and the distance between the inner wall of the reactor and the outer surface of the catalyst is less than 0.3 mm.

[0009] In an embodiment, the reactor is provided with a heat preservation layer outside.

[0010] In an embodiment, the nozzle end of the tail gas injection pipe is arranged opposite to the gas inlet, and the nozzle end of the tail gas injection pipe is provided with a nozzle.

[0011] In an embodiment, the mulch combustion tail gas treatment device is in the shape of a door, three reactors are arranged on the left side and the right side of the mulch combustion tail gas treatment device respectively, and the reactors are communicated through connecting pipes.

[0012] Compared with the prior art, the present application has at least the following beneficial effects:

[0013] The mulch combustion tail gas treatment device in the present application comprises a plurality of reactors connected in series, each reactor is provided with a tail gas injection pipe used for conveying mulch combustion tail gas, so that the input amount of mulch combustion tail gas of each reactor can be controlled individually, the gas inlet of the first reactor can be communicated with the outlet of the hot air fan and the outlet of the combustion air fan, so that the entire mulch combustion tail gas treatment device can be preheated before the reactor is started, the gas circulation process of the internal process is optimized, and the heat dissipation effect is improved.

[0014] The exhaust pipe is not only provided with the first waste gas discharge pipe used for discharging CO2, but also provided with the second waste gas discharge pipe used for introducing the mulch combustion tail gas not participating in the reaction into the reactor again, so that the harm of the mulch combustion tail gas treatment to the environment is reduced.

[0015] The mulch film combustion exhaust gas treatment device in this application can achieve temperature control of each stage of the reactor by activating the high-temperature combustion exhaust gas inlet valve of the mulch film in stages and appropriately controlling the air intake of each valve. This ensures that the reaction temperature of each reactor is stable between 430°C and 450°C, ensuring that the reaction proceeds in an orderly manner. It effectively avoids damage to the catalyst life due to excessively high local temperatures, thus guaranteeing the stable operation and lifespan of the mulch film combustion exhaust gas treatment device. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the mulch film combustion exhaust gas treatment device in the embodiments of this application;

[0017] Figure 2 This is a schematic diagram of the reactor structure in an embodiment of this application;

[0018] Figure 3 This is a schematic diagram of the catalyst structure in the embodiments of this application.

[0019] Reference numerals: 1. Reactor; 101. Tail gas injection pipe; 102. Mixing chamber; 103. Air inlet; 104. Catalyst layer; 105. Catalyst; 106. Temperature measuring unit; 107. Air outlet; 108. Steel wire pad; 2. Connecting pipe; 3. Exhaust pipe; 301. First exhaust gas discharge pipe; 302. Second exhaust gas discharge pipe; 4. Hot air blower; 5. Combustion fan. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the present utility model. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the present utility model.

[0021] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0022] It should be understood that, although the terms first, second, third, etc. can be employed in this disclosure to describe various information, these information should not be limited to these terms, and cannot be understood as indicating or implying relative importance. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of the disclosure, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information. Depending on the context, the word "if" as used herein can be interpreted as "when" or "upon" or "in response to determining".

[0023] In the description of the utility model, unless otherwise specified and limited, it needs to be explained that the terms "mounting", "connection", "connection" should be understood in a broad sense, for example, it can be mechanical connection, it can be the communication inside two elements, it can be direct connection, or it can be indirect connection through intermediate medium, for those skilled in the art, the specific meaning of the above terms can be understood according to specific circumstances.

[0024] In order to better understand the technical scheme of the utility model, the utility model will be described in detail below in combination with the drawings.

[0025] As shown in Figure 1 The embodiment provides a mulch combustion tail gas treatment device, which comprises a reactor connected in multiple stages in series, one end of the reactor 1 is provided with an air inlet 103, the other end of the reactor 1 is provided with an air outlet 107, the air inlet 103 of the first reactor 1 is connected with a three-way valve, the other two inlets of the three-way valve are communicated with the outlet of the hot air fan 4 and the outlet of the combustion air fan 5 respectively, the air outlet 107 of the last reactor is provided with an exhaust pipe 3, the exhaust pipe 3 is provided with a first waste gas discharge pipe 301 and a second waste gas discharge pipe 302, and the port of the first waste gas discharge pipe 301 is provided in an upward open mode.

[0026] As shown in Figure 2 The reactor 1 is sequentially provided with a gas mixing chamber 102 and a catalytic layer 104 along the direction of gas flow, the gas mixing chamber 102 is used to mix mulch combustion tail gas and air, the tail gas injection pipe 101 for injecting mulch combustion tail gas into the gas mixing chamber 102 is arranged in the gas mixing chamber 102, the catalyst 105 for catalytically oxidizing mixed gas is arranged in the catalytic layer 104, the air inlet 103 is arranged at one end of the gas mixing chamber 102, the other end of the gas mixing chamber 102 is communicated with the catalytic layer 104, the catalytic layer 104 is communicated with the air outlet 107, the temperature measuring unit 106 for measuring the temperature of the catalyst is arranged above the catalytic layer 104, the tail gas injection pipe 101 is communicated with the second waste gas discharge pipe 302, the air inlet valve is arranged on the tail gas injection pipe 101, the air inlet valve is electrically connected with the control system, and the control system adjusts the opening degree of the air inlet valve according to the temperature monitored by the temperature measuring unit 106.

[0027] A steel wire pad 108 is installed inside the mixing chamber 102. When exhaust gas and combustion air pass through the steel wire pad 108, the porous structure of the steel wire pad 108 breaks the laminar flow state of the airflow and generates turbulence, allowing the two to mix more thoroughly. This helps to improve the efficiency of the combustion reaction and ensures that the combustible components (such as CO and VOCs) in the exhaust gas react fully with oxygen. On the other hand, the steel wire pad 108 has good thermal conductivity, and the heat generated by the reaction in the catalyst layer 104 can be used to preheat the mixed gas through the steel wire pad 108.

[0028] like Figure 3 As shown, reactor 1 is cylindrical, and catalyst 105 is honeycomb-shaped. The honeycomb catalyst has a large surface area, which increases the contact between the gas and the catalyst. Furthermore, the cylindrical shape of the honeycomb reduces gas flow resistance, lowering the energy consumption of the entire mulch film combustion exhaust gas treatment device. In this embodiment, the distance between the inner wall of reactor 1 and the outer surface of catalyst 105 is less than 0.3 mm, thereby maximizing the contact between the exhaust gas and the catalyst for reaction.

[0029] To reduce heat loss, an insulation layer is installed on the outside of reactor 1 to minimize heat loss and improve energy utilization efficiency. The exhaust gas from the plastic film combustion is delivered sequentially to the reactors according to their stages. To prevent overheating and catalyst burnout during operation of the plastic film combustion exhaust gas treatment device, the control system adjusts the opening of the inlet valve based on the temperature monitored by the temperature measuring unit to maintain the operating temperature of reactor 1 between 200℃ and 600℃.

[0030] The outlet of the tail gas injection pipe 101 in reactor 1 is positioned opposite the inlet 103, which allows air to disperse the tail gas, facilitating the air to carry the high-temperature film combustion tail gas into the catalytic layer 104, thereby improving combustion efficiency. A nozzle is provided at the end of the outlet of the tail gas injection pipe 101 to promote mixing of the tail gas and air, further enhancing reaction efficiency.

[0031] In this embodiment, the mulch film combustion exhaust gas treatment device includes six reactors. In order to reduce the footprint of the mulch film combustion exhaust gas treatment device, the mulch film combustion exhaust gas treatment device is in the shape of a gate, with three reactors on each of the left and right sides, and the reactors are connected to each other through connecting pipe 2.

[0032] This embodiment also provides a method for treating exhaust gas from plastic film combustion, using the above-mentioned plastic film combustion exhaust gas treatment device, including the following steps:

[0033] S1, preheating the mulch combustion tail gas treatment device: start the hot air blower 4, and deliver hot air with a temperature of 185-195℃ to the mulch combustion tail gas treatment device. The hot air is sent to each reactor 1 in turn, and the hot air is continuously delivered for a period of time until the temperature of the catalyst 105 in each reactor 1 reaches above 170℃, so as to prepare for the subsequent catalytic oxidation reaction of the mulch combustion tail gas. Then, the hot air blower is turned off, and the combustion air blower 5 is started to continuously deliver air to the mulch combustion tail gas treatment device;

[0034] S2, starting the reactors step by step:

[0035] S201, open the valve on the tail gas injection pipe in the first reactor, and deliver the mulch combustion tail gas to the first reactor. The mulch combustion tail gas undergoes chemical reaction in the first reactor. Adjust the opening degree of the valve on the tail gas injection pipe in the first reactor to maintain the temperature of the first reactor at 430-450℃. The mulch combustion tail gas after combustion and the mulch combustion not participating in the reaction in the first reactor enter the next reactor, and also bring part of the heat to the next reactor.

[0036] S202, when the temperature of the first reactor is stabilized at 430-450℃ for a period of time, while maintaining the temperature of the first reactor, open the valve on the tail gas injection pipe in the second reactor, and deliver the mulch combustion tail gas to the second reactor. The mulch combustion tail gas undergoes chemical reaction in the second reactor. Adjust the opening degree of the valve on the tail gas injection pipe in the second reactor to maintain the temperature of the second reactor at 430-450℃, which is slightly higher than the temperature of the first reactor. The mulch combustion tail gas after combustion and the mulch combustion not participating in the reaction in the second reactor enter the next reactor, and also bring part of the heat to the next reactor. The temperature of the subsequent reactors is increased after the second reactor is started.

[0037] S203, when the temperature of the first and second reactors is stabilized, fix the opening degree of the valve on the tail gas injection pipe in the first and second reactors, open the valve on the tail gas injection pipe in the third reactor, and deliver the mulch combustion tail gas to the third reactor. The mulch combustion tail gas undergoes chemical reaction in the third reactor. Adjust the opening degree of the valve on the tail gas injection pipe in the third reactor to maintain the temperature of the third reactor at 430-450℃. The temperature of the third reactor is close to the temperature of the second reactor and higher than the temperature of the first reactor. The mulch combustion tail gas after combustion and the mulch combustion not participating in the reaction in the third reactor enter the next reactor, and also bring part of the heat to the next reactor.

[0038] S204, when the temperature of the first to third reactors is stable, the valve opening degree of the tail gas injection pipe in the first to third reactors is fixed, the valve of the tail gas injection pipe in the fourth reactor is opened, the mulch combustion tail gas is transported to the fourth reactor, the mulch combustion tail gas reacts in the fourth reactor, the valve opening degree of the tail gas injection pipe in the fourth reactor is adjusted, the temperature of the fourth reactor is maintained at 430-450 DEG C, the temperature of the fourth reactor is close to the temperature of the third reactor and higher than the temperature of the first and second reactors, the mulch combustion tail gas after combustion and the mulch combustion tail gas not participating in the reaction in the fourth reactor enter the next two reactors, and part of the heat is also brought into the next two reactors;

[0039] S205, when the temperature of the first to fourth reactors is stable, the valve opening degree of the tail gas injection pipe in the first to fourth reactors is fixed, the valve of the tail gas injection pipe in the fifth reactor is opened, the mulch combustion tail gas is transported to the fifth reactor, the mulch combustion tail gas reacts in the fifth reactor, the valve opening degree of the tail gas injection pipe in the fifth reactor is adjusted, the temperature of the fifth reactor is maintained at 430-450 DEG C, the temperature of the fifth reactor is close to the temperature of the second to fourth reactors, the mulch combustion tail gas after combustion and the mulch combustion tail gas not participating in the reaction in the fifth reactor enter the sixth reactor, and part of the heat is also brought into the sixth reactor;

[0040] S206, when the temperature of the first to fifth reactors is stable, the valve opening degree of the tail gas injection pipe in the first to fifth reactors is fixed, the valve of the tail gas injection pipe in the sixth reactor is opened, the mulch combustion tail gas is transported to the sixth reactor, the mulch combustion tail gas reacts in the sixth reactor, the valve opening degree of the tail gas injection pipe in the sixth reactor is adjusted, and the temperature of the sixth reactor is maintained at 430-450 DEG C;

[0041] S3, the exhaust gas is discharged: when each reactor is started to work, the CO2 after the mulch combustion tail gas is burned is discharged to the air through the first exhaust gas discharge pipe 301 due to the small density, and the mulch combustion tail gas not participating in the reaction enters the reactor again through the first exhaust gas discharge pipe 301 and the tail gas injection pipe 101 to participate in the reaction.

[0042] By gradually starting the mulch high-temperature combustion tail gas inlet valve and appropriately controlling the inlet amount of each valve, the temperature control of each reactor can be realized, the reaction temperature of each reactor is stable at 430 DEG C to 450 DEG C, the reaction is ensured to be orderly, and the damage to the catalyst life caused by the local temperature being too high is effectively avoided. The test results show that the ignition temperature can be controlled at about 190 DEG C, the temperature of each reactor can be stably controlled at 430 DEG C to 450 DEG C, the combustion process is stable, the mulch high-temperature combustion tail gas and the combustion air inlet speed are controllable, and the long-term harmless treatment of the mulch high-temperature combustion tail gas can be realized.

[0043] In this embodiment, the temperature of the primary reactor in S201 is finally controlled at 433 DEG C, the temperatures of the secondary and tertiary burners are increased, the temperature of the secondary reactor is increased to 353 DEG C, the temperature of the tertiary reactor is increased to 266 DEG C, and the temperatures of the other subsequent reactors are all above 200 DEG C, which indicates that the heat released by the primary reactor can be effectively transferred to the rear. When the temperature displayed by the temperature measuring unit 106 in the primary reactor exceeds 430 DEG C, the opening of the valve on the tail gas injection pipe is reduced to reduce the amount of ground film combustion tail gas entering the primary reactor, so as to ensure that the temperature in the primary reactor does not exceed 450 DEG C.

[0044] In S202, the temperature of the secondary reactor is finally controlled at 440 DEG C. After the secondary reactor is started, the temperature of the tertiary reactor is increased to 353 DEG C, the temperature of the fourth reactor is increased to 273 DEG C, and the temperatures of the fifth and sixth reactors are not obviously increased, which indicates that the heat transfer effect between the secondary reactor and the tertiary reactor is obvious.

[0045] In S203, the temperature of the tertiary reactor is finally controlled at 443 DEG C. When the first to third reactors are stably working, the temperature of the fourth reactor is increased to 357 DEG C, the temperature of the fifth reactor is increased to 289 DEG C, and the temperature of the sixth reactor is increased to above 230 DEG C, so that the temperature distribution difference of the whole reaction system is small, which is conducive to more effective utilization of the generated heat.

[0046] In S204, the temperature of the fourth reactor is finally controlled at 447 DEG C. When the first to fourth reactors are stably working, the temperature of the fifth reactor is increased to 356 DEG C, and the temperature of the sixth reactor is increased to 300 DEG C.

[0047] In S205, the temperature of the fifth reactor is finally controlled at 445 DEG C. The temperatures of the second to fourth reactors are all 445 DEG C, the temperature of the first reactor is 439 DEG C, and the temperature of the sixth reactor is increased to 359 DEG C.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit them. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or some technical features can be replaced by equivalent ones without departing from the spirit of the present application, and all of them should be covered in the technical solution range of the present application.

Claims

1. A mulch combustion off-gas treatment device characterized by comprising: The reactor comprises multiple reactors connected in series, one end of the reactor is provided with an air inlet, the other end of the reactor is provided with an air outlet, the air inlet of the first reactor is connected with a three-way valve, the other two inlets of the three-way valve are communicated with the outlet of the hot air fan and the outlet of the combustion fan respectively, the air outlet of the last reactor is provided with an exhaust pipe, the exhaust pipe is provided with a first waste gas discharge pipe and a second waste gas discharge pipe, the port of the first waste gas discharge pipe is provided with an upward opening; The reactor is provided with a mixing chamber and a catalyst layer along the direction of gas flow in sequence, the mixing chamber is used to mix mulch combustion tail gas and air, the mixing chamber is provided with a tail gas injection pipe used to inject mulch combustion tail gas into the mixing chamber, the catalyst layer is provided with a catalyst used to catalytically oxidize the mixed gas, the air inlet is arranged at one end of the mixing chamber, the other end of the mixing chamber is communicated with the catalyst layer, the catalyst layer is communicated with the air outlet, the temperature measuring unit used to measure the temperature of the catalyst is arranged above the catalyst layer, the tail gas injection pipe is communicated with the second waste gas discharge pipe, the air inlet valve is arranged on the tail gas injection pipe, the air inlet valve is electrically connected with the control system, the control system adjusts the opening degree of the air inlet valve according to the temperature monitored by the temperature measuring unit.

2. The mulch film burning off gas treatment apparatus according to claim 1, wherein The mixing chamber is provided with a steel wire mat.

3. The mulch film burning off gas treatment apparatus according to claim 1, wherein The reactor is in the shape of a barrel, the catalyst is in the shape of a honeycomb, and the distance between the inner wall of the reactor and the outer surface of the catalyst is less than 0.3 mm.

4. The mulch film burning off gas treatment apparatus according to claim 1, wherein The reactor is provided with an external heat preservation layer.

5. The mulch film burning off gas treatment apparatus according to claim 1, wherein The pipe opening of the tail gas injection pipe in the reactor is arranged opposite to the air inlet, and the end of the pipe opening of the tail gas injection pipe is provided with a nozzle.

6. The mulch film burning off gas treatment apparatus according to claim 1, wherein The mulch combustion tail gas treatment device is in the shape of a door, and three reactors are arranged on the left side and the right side of the mulch combustion tail gas treatment device respectively, and the reactors are communicated through connecting pipes.

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